After electricity was first introduced commercially in the 1880s in the United States and Europe, its use expanded dramatically throughout the world, transforming almost every aspect of daily life. It is now essential to the operation of most modern technological systems and, for this reason, has attained the status of a ‘metatechnology’ (Schon cited in Zimmerman 1992). The inner logic of this metatechnology has shaped contemporary development patterns – grid expansion and urbanization are nearly synonymous; national and local politics – pro-growth and pro-electrification coalitions significantly overlap; social values, culture and identity – to be modern is to be electrified; and community life – our connection to one another (in industrial countries especially) is often electrical (telephone, television, e-mail). It is not surprising; therefore, that electricity supply is often viewed as an essential public good in contemporary society.
Bangladesh's energy infrastructure is quite small, insufficient and poorly managed. The per capital energy consumption in Bangladesh is one of the lowest in the world. Currently, electricity generation per capita in Bangladesh is the lowest in the world, about 154 kWh/per year. Noncommercial energy sources, such as wood, animal wastes and crop residues, are estimated to account for over half of the country's energy consumption. Bangladesh has small reserves of oil and coal, but very large natural gas resources. Commercial energy consumption is mostly natural gas (around 66%), followed by oil, hydropower and coal.
Electricity is the major source of power for country's most of the economic activities. Bangladesh's installed electric generation capacity was 4.7 GW in 2009; only three-fourth of which is considered to be ‘available’. Only 40% of the population has access to electricity. Problems in the Bangladesh's electric power sector include corruption in administration, high system losses, delay in completion of new plants, low plant efficiencies, erratic power supply, electricity theft, blackouts and shortages of funds for power plant maintenance. Overall, the country's generation plants have been unable to meet system demand over the past decade.
In generating and distributing electricity, the failure to adequately manage the load leads to extensive load shedding which results in severe disruption in the industrial production and other economic activities. A recent survey reveals that power outages result in a loss of industrial output worth $1 billion a year which reduces the GDP growth by about half a percentage point in Bangladesh. A major hurdle in efficiently delivering power is caused by the inefficient distribution system. It is estimated that the total transmission and distribution losses in Bangladesh amount to one-third of the total generation, the value of which is equal to US $247 million per year. That is why it is high time for us to rethink the power consumption habits and take the measures to replace the existing loads with energy efficient electrical loads.
1.2 Energy Efficiency
Energy efficiency is defined as the ratio of energy required to perform a specific service to the amount of primary energy used for the process. Improving energy efficiency increases the productivity of basic energy sources by providing given services with less energy resources. For example, space conditioning, lighting or mechanical power can be provided with less input of coal, solar, wind, or uranium in a more energy efficient system. If energy efficiency improvement and energy conservation in the United States were pursued vigorously and consistently with realistic energy price signals, the total cumulative total energy savings from higher energy efficiency standards for residential and commercial equipment that would be effective in the years 2010–2030 amounts to just under 26 quads (quad is a measure of energy used by US department of energy where 1 quad = 1.055*10^18 joules and 3.6*10^6 = 1 kWh). Annual savings amounting to one and a half and three quads in 2025 have been estimated by Lawrence Berkeley National Laboratory (LBNL) and American Council of Energy Efficiency (ACEE) respectively for improved appliances. An additional savings potential from improved building technologies amounting to 4 quads per year has been estimated to be possible for 2025 by the Commission on Energy Policy. Large energy savings are associated with standards for residential electronics products followed by higher efficiency standards for commercial refrigeration, lighting and air conditioning. The next largest savings in the residential sectors could come from higher standards for electric water heaters and lighting . Achieving this savings potential could increase national energy security and help improve the nation’s international balance of payments. Hence improving energy efficiency across all sectors of the economy is an important national objective. It should be noted, however, that free market price signals may not always be sufficient to effect energy efficiency. Hence, legislation on the state and/or national level for energy efficiency standards for equipment in the residential and commercial sector may be necessary.
There is considerable debate whether incentives or mandates are the preferred way to improved energy efficiency. Such measures may be necessary because national surveys indicate that consumers consistently rank energy use and operating costs quite low on the lists of attributes they consider when purchasing an appliance or construct a building. Incentives may be the preferred option provided they induce decision makers to take appropriate action. Unfortunately, in the case of buildings and appliances, the long-term economical benefits of conservation do not rank as high as the initial investment costs. Hence, to achieve increased energy efficiency, mandates may be necessary. Mandates are politically acceptable when the required actions are inexpensive, noncontroversial and simple to perform. When properly enforced, mandates have predictable results and may be the preferred method of achieving energy efficiency.
Every energy conservation measure requires an upfront capital investment and given usual economic constraints, the initial costs of an energy conservation measure is very important. U.S. industry consumes approximately 37% of the nation’s energy to produce 24% of the nation’s GDP. Increasingly, society is confronted with the challenge of moving toward a cleaner, more sustainable path of production and consumption, while increasing global competitiveness. Technology is essential in achieving these challenges. We report on a recent analysis of emerging energy-efficient technologies for industry, focusing on over 50 selected technologies. The technologies are characterized with respect to energy efficiency, economics and environmental performance. This paper provides an overview of the results, demonstrating that we are not running out of technologies to improve energy efficiency, economic and environmental performance and neither will we in the future. The study shows that many of the technologies have important non-energy benefits, ranging from reduced environmental impact to improved productivity and reduced capital costs. For some industries, the costs of complying with environmental regulation can be an important driver for decisions to invest in particular technologies, especially in the nonattainment areas. Of the 54 technologies profiled, 20 had environmental benefits that were either compelling or significant, e.g. reduction criteria pollutant emissions. The benefits mainly fall in the area of reduction of wastes and emissions of criteria air-pollutants. The use of environmentally friendly emerging technologies is often most compelling when it enables the expansion of incremental production capacity while not requiring additional environmental permitting. In selected cases, the use of environmental selection-criteria to invest in these technologies is part of a larger, long-term business strategy towards sustainable development and to stay ahead of the regulatory curve. Many new technologies follow a traditional “S” curve adoption path whereby a small segment of the industry known as early adopters, embraces a new and unproven technology despite high costs and potential risks. As the technology become more common, the perceived risks decrease and the cost of the technology declines. The period needed to achieve a significant market share may vary and depends on the technology characteristics, as well as characteristics of the market and the particular sector. Among the factors that tend to increase rates of market penetration, but that are not typically captured in standard models, are transmissions of more complete information about technology attributes, a growing consumer and business familiarity with the technologies and the awareness of environmental impacts associated with the technologies.
1.3 Advance Technology
Technologically advanced societies have become increasingly dependent on external energy sources for transportation, the production of many manufactured goods and the delivery of energy services. This energy allows people who can afford the cost to live under otherwise unfavorable climatic conditions through the use of heating, ventilation and/or air conditioning. Level of use of external energy sources differs across societies, as do the climate, convenience, levels of traffic congestion, pollution and availability of domestic energy sources. Under the circumstances new technologies for reduced and controlled power consumption must be introduced in our country.
1.3.1 Zero Energy Home
A home which can generate its own energy with no carbon emission is called zero energy home (ZEH). A zero energy home can be implemented by using low power consumption technique, energy efficient equipments, efficient constructional design, renewable energy and smart metering. It can contribute on power generation by supplying power to grid. So; ZEH is very important factor to be introduced.
1.3.2 Lighting Load
Electricity crisis is a common phenomenon in our country. It’s a regular suffering for the people of different locations of the country. In this suffering lighting loads play a vital role because it is the only load which is used all along the day in the whole year. As a result a big portion of power consumption is covered by lighting loads. A statistics is given bellow [1-Energy pack ][2-newspaper- the prothom alo 15 october,2011 ]
4896 MW National Consumption
30% of 4896 MW = 1469 MW Lighting Consumption
Figure 1.1 Energy consumption of lighting loads versus other loads.
From this, it becomes very easy to say that how much electrical power is required only for lighting loads. So lighting load is our main concern in this thesis work.
1.3.3 Smart Metering
Smart metering is without any doubt a topic that recently has attracted much attention. Many countries within the Europe, USA and outside are already involved in projects with smart metering on a demonstration scale or larger. Smart metering generally involves the installation of an intelligent meter at residential customers and the regular reading, processing and feed back of consumption data to the customer. A "smart" meter has the following capabilities:
Real-time or near-time registration of electricity use and possibly electricity generated locally e.g., in case of photovoltaic cells;
Offering the possibility to read the meter both locally and remotely (on demand);
Remote limitation of the throughput through the meter (in the extreme case cutting of the electricity to the customer)
Interconnection to premise-based networks and devices (e.g. distributed generation)
Energy management is one of the major problems in Bangladesh because there is a big in equilibrium between demand and generation. Our main objective is to make awareness about the fact and let people know how many countries in the world have made best use of their little resources to alleviate the scarcity of electrical power and we also aim to introduce people to the new advanced technologies that are being used all over the world. One of our basic aims is rethinking of power consumption and load management.
Our thesis was based on the rethinking of existing loads where we focused on replacing the existing lighting loads with energy efficient lighting fixtures. We also tried to introduce the new the technologies that can be implemented to mitigate the huge distance between demand and generation and new ways of consumption behavior to maximize the utilization of produced electrical power.
The thesis is organized in five chapters. Chapter one represents introductory portion of the thesis. Chapter two discusses the Zero Energy Home Technology. Chapter three discusses the advance lighting loads technology. Chapter four discusses smart metering technology. Chapter five represents the conclusive proposals for the existing load consumption criterion.
A net Zero Energy Home (ZEH) is a home with greatly reduced energy needs through efficiency gains such that the balance of the energy needs can be supplied by renewable technologies. A ZEH typically uses traditional energy sources such as the electric and natural gas utilities when on-site generation does not meet the loads. When the on-site generation is greater than the home’s loads, excess electricity is exported to the utility grid.
So we can say that nearly zero-energy home means a home that has very good energy performance. The nearly zero or very low amount of energy required should be supplied to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby.
The basic approach at the individual home level is always a two-step concept, consisting of-
Reducing the energy demand
Exporting energy optimally into external grids.
2.1.1 Purpose of ZEH
Energy can be harvested on-site—usually through a combination of energy producing technologies like Solar and Wind—while reducing the overall use of energy with extremely efficient high voltage alternative current (HVAC) and Lighting technologies. The zero-energy design principle is becoming more practical to adopt due to the increasing costs of traditional fossil fuels and their negative impact on the planet's climate and ecological balance. The main purposes of zero energy home are-
To reduce peak demand load
To increase the stability of national grid
Save energy for future use
Through energy saving individual can be a source for grid
Now days, Zero Energy Home is becoming more important technology for those countries where energy supply is a big problem and energy consumption is huge. The Zero Net Energy approach has potential to reduce emissions and reduce dependence on fuels. Some important features of ZEH are listed bellow-
Isolation for home owners from future energy price increases.
Increased comfort due to more-uniform interior temperatures.
Reduced requirement for energy austerity.
Reduced total cost of ownership due to improved energy efficiency.
Reduced total net monthly cost of living.
Improved reliability – photovoltaic systems have 25-year warranties – seldom fail during weather problems.
Extra cost is minimized for new construction compared to an afterthought retrofit.
Higher resale value as potential owners demand more ZEHs than available supply.
The value of a ZEH home relative to similar conventional home should increase every time energy costs increase.
Though ZEH has a lot of advantages but it has some disadvantages too. These are-
Initial costs can be higher – effort required to understand, apply and qualify for ZEH subsidies.
Very few designers or builders have the necessary skills or experience to build ZEHs.
Possible declines in future utility company renewable energy costs may lessen the value of capital invested in energy efficiency.
New photovoltaic solar cell equipment technology price has been falling at roughly 17% per year – It will lessen the value of capital invested in a solar electric generating system – Current subsidies will be phased out as photovoltaic mass production lowers future price.
While the individual house may use an average of net zero energy over a year, it may demand energy at the time when peak demand for the grid occurs. In such a case, the capacity of the grid must still provide electricity to all loads. Therefore, a ZEH may not reduce the required power plant capacity.
Without an optimized thermal envelope the embodied energy, heating and cooling energy and resource usage is higher than needed. ZEH by definition do not mandate a minimum heating and cooling performance level thus allowing oversized renewable energy systems to fill the energy gap.
Solar energy capture using the house envelope only works in locations unobstructed from the South. The solar energy capture cannot be optimized in South facing shade or wooded surroundings.
2.1.2 Modern Technology and ZEH
The development of modern Zero Net Energy (ZNE) homes became possible not only through the progress made in new construction technologies and techniques but it has also been significantly improved by academic research on traditional and experimental homes, which collected precise energy performance data. Today's advanced computer models can show the efficacy of engineering design decisions. Energy use can be measured in different ways (relating to cost, energy, or carbon emissions) and, irrespective of the definition used, different views are taken on the relative importance of energy harvest and energy conservation to achieve a net energy balance. Although zero energy homes remain uncommon in developed countries, they are gaining importance and popularity. A home approaching Zero Net Energy use may be called a near-zero energy home or ultra-low energy house. Homes that produce a surplus of energy during a portion of the year may be known as homes. If the home is located in an area that requires heating or cooling throughout parts of the year, it is easier to achieve Zero Net Energy consumption when the available living space is kept small.
To establish a ZEH, it can be divided into four major parts:
Low power consumption
Efficient home constructional design
Energy management and control system
2.2 Low Power Consumption
Using ZEH design goals helps us of designing low-energy homes with a percent energy savings from general loads and all appliances used in ZEH are low power consuming loads.
Today all the appliances used in ZEH are of alternative kind from normal loads. Some of these are briefly discussed in this report:
2.2.1 ZEH Lighting Appliances
In general household the types of loads used for lighting are incandescent which a huge loss in terms of output to has given input. In ZEH the loads used for lighting are basically solid state DC lighting which includes Compact Fluorescent Lamp (CFL), Light Emitting Diodes (LED).
2.2.2 Cooling without Air Conditioning
One energy efficient alternative to traditional air conditioning is an evaporative cooling system, often called a "swamp cooler". Evaporative coolers are an excellent option for interior cooling in dry climates.
A swamp cooler works by drawing air in through a vented surface of the cooler box, where it flows through water saturated pad and is blown into the household or RV ventilation system. The heat in the air is used to evaporate water in the cooling pad, leaving the air much cooler and slightly more humid than when it entered the cooler. Swamp coolers are so much more efficient than traditional air conditioning because the only electrical draw in the cooling system is the circulating fan and a small circulating pump. They also avoid the environmental hazards of freon.
Figure 2.1 Evaporative Cooler
2.2.3 Alternatives to Electric Water Heating
The most efficient method of hot water heating for household use is a propane tankless heater . These water heaters consist of a coiled copper pipe, with a propane burner at the bottom of the unit. They are usually wall mounted and no larger than a suitcase, making them very space efficient as well. Water is heated on demand, so propane is only used when hot water is actually in use. There is no need to keep a tank full of water heated 24 hours a day. Also, since the burner is only heating the small volume of water present in the copper pipe, the water is heated very quickly. One of the most appealing advantages to tankless heaters is that the hot water supply never runs out, unless the propane runs out or the water supply dries up.
2.2.4 Energy Efficient Refrigerator
For energy efficient refrigeration system in zero energy homes refrigerator with the condenser and compressor mounted on the top of the unit is much more preferable. Not only is the surface area between the cooling system and the refrigerator reduced, leading to less heat absorption by the refrigeration area, but it is far easier to insulate the top freezer compartment from the heat than it would be to effectively insulate the entire back of the unit.
2.2.5 Gas Heated Clothing Dryers
Though electric clothing dryers are not used commonly in Bangladesh, the amount of power they consume during use is tremendous. There is currently no way to completely eliminate electric use by a dryer because the drum motors are electric powered, but electricity consumption can be greatly reduced by switching to a gas heated model. Using gas heat eliminates the majority of the power draw. A high-efficiency washer with an effective extraction spin cycle can also greatly decrease the power use (whether electric or propane) of a clothing dryer.
2.3 Efficient Home Constructional Design
The construction of Zero Energy Home needs specific designs to be implemented.
2.3.1 Passive Solar Home Design
The windows, walls and floors of a home can be designed to collect, store and distribute solar energy in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design  or climatic design. Unlike active solar heating systems, passive solar design does not involve the use of mechanical and electrical devices, such as pumps, fans, or electrical controls to move the solar heat. Passive solar homes range from those heated almost entirely by the sun to those with south-facing windows that provide some fraction of the heating load. The difference between a passive solar home and a conventional is the constructional design. The key is designing a passive solar home to best take advantage of the local climate.
Passive solar design techniques can be applied most easily when designing a new home. However, existing homes can be adapted or "retrofitted" to passively collect and store solar heat. It minimizes energy losses, energy recovery.
As a fundamental law, heat moves from warmer materials to cooler ones until there is no longer a temperature difference between the two. To distribute heat throughout the living space, a passive solar home design makes use of this law through the following heat-movement and heat-storage mechanisms:
Conduction: Conduction is the way heat moves through materials, traveling from molecule to molecule. Heat causes molecules close to the heat source to vibrate vigorously and these vibrations spread to neighboring molecules; thus transferring heat energy.
Convection: Convection is the way heat circulates through liquids and gases. Lighter, warmer fluid rises and cooler, denser fluid sinks. For instance, warm air rises because it is lighter than cold air, which sinks. This is why warmer air accumulates on the second floor of a house, while the basement stays cool. Some passive solar homes use air convection to carry solar heat from a south wall into the home's interior.
Radiation: Radiant heat moves through the air from warmer objects to cooler ones. There are two types of radiation important to passive solar design: solar radiation and infrared radiation. When radiation strikes an object, it is absorbed, reflected, or transmitted, depending on certain properties of that object. Opaque objects absorb 40%–95% of incoming solar radiation from the sun, depending on their color. Darker colors typically absorb a greater percentage than lighter colors. This is why solar-absorber surfaces tend to be dark colored. Bright-white materials or objects reflect 80%–98% of incoming solar energy. Inside a home, infrared radiation occurs when warmed surfaces radiate heat towards cooler surfaces .
These surfaces can include walls, windows, or ceilings in the home. Clear glass transmits 80%–90% of solar radiation, absorbing or reflecting only 10%–20%. After solar radiation is transmitted through the glass and absorbed by the home, it is radiated again from the interior surfaces as infrared radiation. Although glass allows solar radiation to pass through, it absorbs the infrared radiation. The glass then radiates part of that heat back to the home's interior. In this way, glass traps solar heat entering the home.
Thermal Capacitance: Thermal capacitance refers to the ability of materials to store heat. Thermal mass refers to the materials that store heat. Thermal mass stores heat by changing its temperature, which can be done by storing heat from a warm room or by converting direct solar radiation into heat. The more thermal mass, the more heat can be stored for each degree rise in temperature. Masonry materials, like concrete, stones, brick and tile, are commonly used as thermal mass in passive solar homes. Water also has been successfully used.
Elements of Solar Home Design: The following five elements constitute a complete passive solar home design. Each performs a separate function, but all five must work together for the design to be successful:
Aperture (Collector): Aperture is the large glass (window) area through which sunlight enters the home. Typically, the aperture(s) should face within 30 degrees of true south and should not be shaded by other homes or trees from 9 a.m. to 3 p.m. each day during the heating season.
Absorber: Absorber is the hard, darkened surface of the storage element. This surface which could be that of a masonry wall, floor or partition (phase change material), or that of a water container sits in the direct path of sunlight. Sunlight hits the surface and is absorbed as heat.
Figure 2.2 Five elements of passive solar home design
Thermal Mass: Thermal mass is the materials that retain or store the heat produced by sunlight. The difference between the absorber and thermal mass, although they often form the same wall or floor, is that the absorber is an exposed surface whereas thermal mass is the material below or behind that surface.
Distribution: The method by which solar heat circulates from the collection and storage points to different areas of the house is called as distribution. A strictly passive design will use the three natural heat transfer modes—conduction, convection and radiation—exclusively. In some applications, however, fans, ducts and blowers may help with the distribution of heat through the house.
Control: Roof overhangs can be used to shade the aperture area during summer months. Other elements that control under and/or overheating include electronic sensing devices, such as a differential thermostat that signals a fan to turn on; operable vents and dampers that allow or restrict heat flow; low-emissivity blinds and awnings.
2.3.2 Window Location and Glazing Type
In cooling climates, particularly effective strategies include preferential use of north-facing windows and generously shaded south-facing windows. The following types of glazing help reduce solar heat gain, lowering a window's solar heat gain coefficient (SHGC). The SHGC represents the fractional amount of the solar energy that strikes the window that ends up warming the house:
Low-Emissivity Window Glazing or Glass: Low-emissivity (Low-E) coatings on glazing or glass control heat transfer through windows with insulated glazing. Windows manufactured with Low-E coatings typically are more costly than regular windows, but they are by far energy efficient than those.
A Low-E coating is a microscopically thin, virtually invisible, metal or metallic oxide layer deposited directly on the surface of one or more of the panes of glass. The Low-E coating reduces the infrared radiation from a warm pane of glass to a cooler pane. Different types of Low-E coatings have been designed to allow for high solar gain, moderate solar gain, or low solar gain. A Low-E coating can also reduce a window's visible transmittance unless you use one that's spectrally selective.
To keep the sun's heat out of the house (for hot climates, east and west-facing windows and unshaded south-facing windows), the Low-E coating should be applied to the outside pane of glass. If the windows are designed to provide heat energy in the winter and keep heat inside the house (typical of cold climates), the Low-E coating should be applied to the inside pane of glass.
Window manufacturers apply Low-E coatings in either soft or hard coats. Soft Low-E coatings degrade when exposed to air and moisture, are easily damaged and have a limited shelf life. Therefore, manufacturers carefully apply them in insulated multiple-pane windows. Hard Low-E coatings, on the other hand, are more durable and can be used in add-on (retrofit) applications. The energy performance of hard-coat, Low-E films is slightly poorer than that of soft-coat films.
Tinted: Heat-Absorbing, tinted Window Glazing or Glass Heat-absorbing window glazing contains special tints that change the color of the glass. Tinted glass absorbs a large fraction of the incoming solar radiation through a window. This reduces the solar heat gain coefficient, visible transmittance and glare. Some heat, however, continues to pass through tinted windows by conduction and re-radiation. Therefore, the tint doesn't lower a window's U-factor. However, inner layers of clear glass or spectrally selective coatings can be applied on insulated glazing to help reduce these types of heat transfer.
Gray- and bronze-tinted windows—the most common—reduce the penetration of both light and heat into homes in equal amounts (i.e. not spectrally selective). Blue- and green-tinted windows offer greater penetration of visible light and slightly reduced heat transfer compared with other colors of tinted glass. In hot climates, black-tinted glass should be avoided because it absorbs more light than heat. Tinted heat-absorbing glass reflects only a small percentage of light, so it does not have the mirror-like appearance of reflective glass.
Reflective Window Glazing or Glass: Reflective coatings on window glazing or glass reduce the transmission of solar radiation, blocking more light than heat. Therefore, they greatly reduce a window's visible transmittance (VT) and glare, but they also reduce a window's solar heat gain coefficient (SHGC).
Reflective coatings usually consist of thin, metallic layers. They come in a variety of metallic colors, including silver, gold and bronze.
Reflective window glazing is commonly used in hot climates where solar heat gain control is critical. However, the reduced cooling energy demands they achieve can be offset by the resulting need for additional electrical lighting, so reflective glass is mostly used just for special applications.
2.3.3 Air Sealing
Air sealing is another type of constructional design where it is used to seal cracks and openings properly in home which can significantly reduce heating and cooling costs, improve home durability and create a healthier indoor environment.
During cold or windy weather, too much air may enter the house and warmer and less windy, not enough air may enter. In case of cold and warm weather air sealing is the best use of maximizing the comfort of the house through controlling the air flow. It also improves the indoor health condition by sealing the moldy and dusty air flow in the house.
Insulation is a constructional design which is used to provide the resistance to heat flow. The more heat flow resistance the insulation provides, the lower heating and cooling costs.
To maintain comfort, the heat lost in the winter must be replaced by heating system and the heat gained in the summer must be removed by cooling system. Properly insulating the home will decrease this heat flow by providing an effective resistance to the flow of heat.
For energy efficiency, insulation should be provided from the roof down to its foundation. This includes the following areas:
Attic access doors to unfinished attics
Knee walls in finished attics
Ducts in unconditioned spaces
Floors above unheated garages
2.3.5 Moisture Control
Moisture control contributes to a home's overall energy efficiency by assisting air sealing and insulation efforts. The best strategy for controlling moisture in home depends on climate and how home is constructed and how moisture moves through home. Moisture control strategies typically include the following areas of a home:
o Crawl space
o Slab-on-grade floors
Ventilation is important consideration for a healthy, energy-efficient home which is needed to exchange of indoor air with outdoor air—to reduce indoor pollutants, moisture and odors.
Contaminants such as formaldehyde, volatile organic compounds and radon can accumulate in poorly ventilated homes, causing health problems. Excess moisture in a home can generate high humidity levels. High humidity levels can lead to mold growth and structural damage to the home. There are three basic ventilation strategies:
Natural Ventilation: Natural ventilation used to be the most common ventilation method of allowing fresh outdoor air to replace indoor air in a home. It is suitable where uncontrolled air movement into a home through cracks, small holes and vents, such as windows and doors and not recommended for tightly sealed homes.
Whole-house Ventilation: Whole-house ventilation systems provide controlled, uniform ventilation throughout a house. These systems use one or more fans and duct systems to exhaust stale air and/or supply fresh air to the house.
There are four types of systems:
Exhaust Ventilation Systems : Force inside air out of a home.
Supply Ventilation Systems: Force outside air into the home.
Balanced Ventilation Systems: Force equal amounts quantities of air into and out of the home.
Energy Recovery Ventilation Systems: Transfer heat from incoming or outgoing air to minimize energy loss.
Spot Ventilation: Spot ventilation improves the effectiveness of other ventilation strategies—natural and whole house—by removing indoor air pollutants and/or moisture at their source. Spot ventilation includes the use of localized exhaust fans, such as those used above kitchen ranges and in bathrooms.
2.4 Electricity Harvest
ZEHs harvest available energy to meet their electricity and heating or cooling needs. In the case of individual houses, various micro generation technologies may be used to provide heat and electricity to the home, using solar system or wind turbines for electricity and biofuels or solar collectors Energy harvesting is most often more effective (in cost and resource utilization) when done on a local but combined scale, for example, a group of houses, co-housing, local district, village, etc. rather than an individual basis.
2.4.1 Small Solar Electric Systems
Solar electric systems, also known as photovoltaic (PV) systems, convert sunlight into electricity. A small solar electric or photovoltaic (PV) system can be a reliable and pollution-free producer of electricity for home or office. Small PV systems also provide a cost-effective power supply in locations where it is expensive or impossible to send electricity through conventional power lines. The amount of power generated by a solar system at a particular site depends on how much of the sun's energy reaches it .
Working Principle: Solar cells—the basic home blocks of a PV system—consist of semiconductor materials. When sunlight is absorbed by these materials, the solar energy knocks electrons loose from their atoms. This phenomenon is called the "photoelectric effect." These free electrons then travel into a circuit built into the solar cell to form electrical current. Only sunlight of certain wavelengths will work efficiently to create electricity. PV systems can still produce electricity on cloudy days, but not as much as on a sunny day.
PV arrays can be mounted at a fixed angle facing south, or they can be mounted on a tracking device that follows the sun, allowing them to capture the most sunlight over the course of a day. Because of their modularity, PV systems can be designed to meet any electrical requirement, no matter how large or how small. It also can be connected to an electric distribution system (grid-connected), or they can stand alone (off-grid).
Small Solar Electric System Components: A typical small solar electric or photovoltaic (PV), system consists of these components:
Modules or panels (which consist of solar cells)
Arrays (which consist of modules)
The balance-of-system equipment required depends which of the following systems is being used:
A typical small solar electric system usually includes the following balance-of-system components:
Mounting racks and hardware for the panels
Wiring for electrical connections
Power conditioning equipment, such as an inverter
Batteries for electricity storage (optional).
Stand-by gasoline electric generator
2.4.2 Small Wind Electric Systems
Small wind electric systems are one of the most cost-effective home-based renewable energy systems. These systems are also nonpolluting. Small wind electric systems can also be used for a variety of other applications, including water pumping on farms and ranches. Small wind turbines range in size from 400 watts to 20 kilowatts.
Working Principle: Wind is created by the unequal heating of the Earth's surface by the sun. Wind turbines convert the kinetic energy in wind into clean electricity. When the wind spins the wind turbines blades; a rotor captures the kinetic energy of the wind and converts it into rotary motion to drive the generator. The manufacturer can provide information on the maximum wind speed at which the turbine is designed to operate safely. Most turbines have automatic over speed-governing systems to keep the rotor from spinning out of control in very high winds.
Components: To capture and convert the wind's kinetic energy into electricity, a home wind energy system generally comprises the following:
A wind turbine consisting of blades attached to a rotor, generator/alternator mounted on a frame and usually a tail
A tower Balance-of-system components, such as controllers, inverters and/or batteries.
Facts that must be considered before establishing a wind turbine is good wind resource, requirement of land and suitable height for turbine tower.
2.4.3 Micro Hydropower Systems
Micro hydropower systems usually generate up to 100 kilowatts (kW) of electricity . A 10-kilowatt micro hydropower system generally can provide enough power for a large home, a small resort, or a hobby farm. Bangladesh is a river enriched country. So Bangladesh has high potential for small hydro turbine.
Working Principle: Hydropower systems use the energy in flowing water to produce electricity or mechanical energy. Although there are several ways to harness the moving water to produce energy, run-of-the-river systems, which do not require large storage reservoirs, are often used for micro hydropower systems.
For run-of-the-river micro hydropower systems, a portion of a river's water is diverted to a water conveyance channel, pipeline, or pressurized pipeline (penstock)—that delivers it to a turbine or waterwheel. The moving water rotates the wheel or turbine, which spins a shaft. The motion of the shaft can be used for mechanical processes, such as pumping water, or it can be used to power an alternator or generator to generate electricity.
Components: Run-of-the-river micro hydropower systems consist of these basic components:
Water conveyance—channel, pipeline, or pressurized pipeline (penstock) that delivers the water
Turbine, pump, or waterwheel—transforms the energy of flowing water into rotational energy
Alternator or generator—transforms the rotational energy into electricity
Regulator—controls the generator
Wiring—delivers the electricity.
2.4.4 Small Hybrid Solar and Wind Electric System
A small hybrid electric system combines wind and solar (photovoltaic) technologies offer several advantages over either single system. In Bangladesh, wind speeds are low in the summer when the sun shines brightest and longest.
The wind is strong in the winter when less sunlight is available. Because the peak operating times for wind and solar systems occur at different times of the day and year, hybrid systems are more likely to produce power when you need it. It uses battery banks typically sized to supply the electric load for 2 or 3 days.
Figure 2.3 A hybrid power system
2.5 Energy Management and Load Control in ZEH
To achieve the purpose of ZEH energy using behavior of general consumer is needed to be changed. Technology is a (relatively) new factor that can greatly assist in achieving changes in energy-using behavior. Two types of technology can be used to achieve behavior change:
Advanced metering Load control technology
Advanced metering is a metering system that records customer consumption (and possibly other parameters) hourly or more frequently and that provides for daily or more frequent transmittal of measurements over a communication network to a central collection point.
Figure 2.4 A residential home connected to grid through smart metering
Advanced metering refers to the full measurement and collection system and includes customer meters (usually smart meters) , communication networks and data management systems. This full measurement and data collection system is commonly referred to as advanced metering infrastructure (AMI).
Smart meter typically include one-way or two-way communications between the energy supplier and the meter. Smart meters are used for load control and management in ZEH.
Load control comprises a system or program that enables end-use loads to be changed in response to particular events, e.g. high electricity prices or problems on the electricity network.
Lighting is one of the most heavily used loads in the current load system but the light loads are not used energy efficiently. The bulbs used are not energy efficient. Hence we are losing huge amount of power due to lack of energy efficient lighting.
Lighting or illumination is the deliberate application of light to achieve some aesthetic or practical effect. Lighting includes use of both artificial light source such as lamps and natural illumination of interiors from daylight. Day lighting (through windows, skylights, etc.) is often used as the main source of light during daytime in buildings given its high quality and low cost. Artificial lighting represents a major component of energy consumption, accounting for a significant part of all energy consumed worldwide. Artificial lighting is most commonly provided today by electronic lights, but gas lighting, candles, or oil lamps were used in the past and still are used in certain situations. Proper lighting can enhance task performance or aesthetics, while there can be energy wastage and adverse health effect of poorly designed lighting. Indoor lighting is a form of fixture or furnishing and a key part of interior design. Lighting can also be an intrinsic component of landscaping.
3.2 Lighting Equipments
Commonly called 'light bulbs', lamps are the removable and replaceable part of a light fixture, which converts electrical energy into electromagnetic radiation. While lamps are often rated in terms of how much power they use in watts, the power does not necessarily correspond to the amount of light produced. For example, a 60 W incandescent light bulb produces about the same amount of light as a 13 W compact fluorescent lamp. Each of these technologies has a different efficacy in converting electrical energy to visible light. Visible light output is typically measured in lumens. This unit only quantifies the visible radiation and excludes invisible infrared and ultraviolet light.
It is important to be able to differentiate types of lamps and lamp technologies. These include:
Ballast: Ballast is an auxiliary piece of equipment designed to start and properly control the flow of power to discharge light sources such as fluorescent and high intensity discharge (HID) lamps. Some lamps require the ballast to have thermal protection.
Fluorescent Light: A long straight tube coated with phosphor containing low pressure mercury vapor that produces white light.
Halogen: High pressure incandescent lamps containing halogen gases such as iodine or bromine, allowing filaments to be operated at higher temperatures.
Neon: A low pressure gas contained within a glass tube; the color emitted depends on the gas.
Light Emitting Diodes: Light emitting diodes (LED) are solid state lamps without the filaments that would burn out on ordinary light bulbs. LEDs emit light produced from the movement of electrons in a semiconductor material.
Compact Fluorescent Lamps: CFLs are designed to replace incandescent lamps in existing and new installations.
3.3 Energy Efficient Lighting Technology
There is great potential for saving electricity, reducing the emission of greenhouse gases associated with Electricity production and reducing consumer energy costs through the use of more efficient lighting technologies as well as advanced lighting design practices and control strategies. Modern efficient technologies that are introduced into the world in the future can further reduce energy use and increase financial savings.
Form the Energy –Efficient Lighting Technology, we came to know that-
An overview of both conventional and newer, more efficient lighting technologies. The discussion includes:
Design of energy-efficient lighting systems.
Descriptions, applications and efficacies of various lighting technologies (including lamps, ballasts, fixtures and controls).
Operation of energy-efficient lighting systems.
Current lighting markets and trends.
Lighting efficiency standards and incentive programs and Cost-effectiveness of efficient lighting technologies.
3.4 Design of Energy-Efficient Lighting Systems
Energy efficiency is an important component of lighting system design; however, lighting designers must also consider economics, productivity, aesthetics and consumer preference.
Efficient, high-quality lighting design includes,
Attention to task and ambient lighting,
Effective use of day lighting,
Effective use of lighting controls and
Use of the most cost-effective and efficacious technologies.
For visual comfort and ease of visual transition between task and ambient spaces, the ambient lighting in a room should be at least one-third as bright as the lighting of the task areas.
Effective use of day lighting is also an important component of lighting system design. To make good use of natural light, however, requires more than the simple addition of multiple windows. The use of window glazes can limit heat transmission while permitting visible light to pass through a window or skylight.
3.5 Properties of Light Sources
The common properties of the light sources are listed bellow-
A lamp is rated in terms of its efficacy, which is the ratio of the amount of light emitted (lumens) to the power (watts) drawn by the lamp. The unit used to express efficacy is lumens per watt (LPW). The theoretical limit of efficacy is 683 LPW and would be produced by an ideal light source emitting monochromatic radiation with a wavelength of 555 nm. The most efficient white light source in the laboratory provides 275–310 LPW. Of lamps presently in the market, the most efficient practical light source, the T5 fluorescent lamp with electronic ballast, produces about 100 LPW. High-pressure sodium (not a white light source) can produce as high as 130 LPW.
Lamps also differ in terms of their cost, size, color, lifetime, optical controllability, damnability, lumen maintenance, reliability, convenience in use, maintenance requirements, disposal, environmental impacts (mercury, lead)and electromagnetic and other emissions (e.g. radio interference, ultraviolet (UV) light and noise).
3.5.2 Lumen Maintenance
The lumen maintenance of a lamp refers to the extent to which the lamp sustains its lumen output and therefore efficacy, over time. Initial lumens are measured at the beginning of the lamp’s life, while mean lumens are measured after a lamp has been used for a percentage of its rated life.
3.5.3 Color Properties
There are two types of color properties. These are
Color Rendering index
Color Temperature: The color of a lamp’s light expressed in degrees Kelvin (K). The color temperature of a lamp is the temperature at which an ideal blackbody radiator would emit light that is the same color as the light of the lamp.
Color Rendering Index (CRI): A measure of how surface colors appear when illuminated by a lamp compared to how they appear when illuminated by a reference source of the same color temperature.
3.5.4 Optical Controllability
The optical controllability of a lamp describes the extent to which a user can direct the light of the lamp to the area where it is desired. The optical controllability depends on the size of the light-emitting area, which determines the beam spread of the light emitted. In addition, controllability depends on the fixture in which the lamp is used. Incandescent lamps emit light from a small filament area: they are almost point sources of light and their optical controllability is excellent. In contrast, fluorescent lamps emit light from their entire phosphorous bulb wall area; their light is extremely diffuse and their controllability is poor i.e. area increases controllability decreases and area decreases controllability increases.
3.6 Lighting Technologies
Lighting technology includes lighting description, efficacy and its application. Lighting system components fall into four basic categories:
An electric lamp is a device that converts electric energy into light. Following is a description of common lamp types with discussion on their efficacy and applications.
Different types of lamps-
High-Intensity Discharge lamps
Low pressure Sodium lamps
Light Emitting Diodes
220.127.116.11 Incandescent Lamps
The incandescent light bulb, incandescent lamp or incandescent light globe makes light by heating a metal filament wire to a high temperature until it glows. The hot filament is protected from air by a glass bulb that is filled with inert gas or evacuated. In a halogen lamp, a chemical process that returns metal to the filament prevents its evaporation. The light bulb is supplied with electrical current by feed-through terminals or wires embedded in the glass. Most bulbs are used in a socket (a housing giving mechanical support to the bulb, keeping its terminals in contact with the supply current terminals).
Incandescent light bulbs are gradually being replaced in many applications by other types of electric lights, such as fluorescent lamps, compact fluorescent lamps, cold cathode fluorescent lamps (CCFL), high-intensity discharge lamps and light-emitting diodes (LED). These newer technologies improve the ratio of visible light to heat generation.
Figure 3.1 Xenon Halogen incandescent Lamp (105 W) with an E27 base, intended for direct replacement of a non-halogen bulb.
Luminous efficacy of a light source is a ratio of the visible light energy emitted (the luminous flux) to the total power input to the lamp . Visible light is measured in lumens, a unit which is defined in part by the differing sensitivity of the human eye to different wavelengths of light. Not all wavelengths of visible electromagnetic energy are equally effective at stimulating the human eye; the luminous efficacy of radiant energy is a measure of how well the distribution of energy matches the perception of the eye. The maximum efficacy possible is 683 lm/W for monochromatic green light at 555 nanometers wavelength, the peak sensitivity of the human eye. For white light, the maximum luminous efficacy is around 240 lumens per watt, but the exact value is not unique because the human eye can perceive many different mixtures of visible light as "white".
The disadvantages of Halogen general service lamps are available but still relatively rare.
The main advantages of the incandescent lamps make no annoying noises. Provide no electro-magnetic interference and contain no toxic chemicals essentially. Incandescent lamps have relatively simple installation, maintenance and disposal.
18.104.22.168 Fluorescent Lamps
Fluorescent lamps came into general use in the 1950s. In a fluorescent lamp, gaseous mercury atoms within a phosphor-coated lamp tube are excited by an electric discharge. As the mercury atoms return to their ground state, ultraviolet radiation is emitted. This UV radiation excites the phosphor coating on the lamp tube and causes it to fluoresce, thus producing visible light.
The Advantages of Fluorescent lamps are far more efficacious than incandescent lamps. Fluorescent lamps have long lives and fairly good lumen maintenance. Provide higher initial light output, better lumen maintenance, longer life and improved ballast efficiency.
The Disadvantages of Standard and compact fluorescent lamps can be dimmed, but require special dimming ballasts that cost more than the dimming controls used for incandescent lamps. It is harder to control optically. It emits more UV light. Electronic ballasts may interfere with security equipment, such as that used in libraries and with specialized hospital devices. It contains trace amounts of mercury, a toxic metal and large users are required to either recycle them or dispose of them as hazardous waste.
Types: There are different types of Fluorescent lamps. These are –
T5- Lamp tubes with a diameter of 5/8 in. (16 mm) are called T5s.
T8- Lamp tubes with a diameter of 1 in. (26 mm) are called T8s.
T12- Lamp tubes with a diameter of 1.5 in. (38 mm) are called T12s.
22.214.171.124 Induction Lamps
An induction lamp is a fluorescent lamp where the electric discharge is induced by a magnetic field, rather than an electric field as in a fluorescent lamp and therefore does not have any electrodes
The advantages of Induction lamps are rated at 100,000 h of life. Good colour rendition, induction technology is coming into use for areas.
The disadvantage of IL Maintenance to change the lamp is expensive. It generates electromagnetic interference (EMI).
126.96.36.199 High-Intensity Discharge Lamps
High-intensity discharge (HID) lamps produce light by discharging an electrical arc through a mixture of gases. Compared to a fluorescent lamp, the arc tube in an HID lamp is small enough to permit compact reflector designs with good light control.
188.8.131.52 Low-Pressure Sodium Lamps
Low-pressure sodium (LPS) lamps are discharge lamps that operate at lower arc tube loading pressure than do HID lamps.
184.108.40.206 Light Emitting Diode (LED)
Light emitting diode (LED) lamps have been advocated as the newest and best environmental lighting method. According to the Energy Saving Trust, LED lamps use only 10% power compared to a standard incandescent bulb, where fluorescent lamps use compact 20% and energy saving halogen lamps 70%. A downside is still the initial cost, which is higher than that of compact fluorescent lamps. General Electric expects to begin producing organic LEDs for architectural use by 2010 .
Efficient lighting is needed for sustainable architecture. A 13 watt LED lamp emits 450 to 650 lumens which is equivalent to a standard 40 watt incandescent bulb . A standard 40 W incandescent bulb has an expected lifespan of 1,000 hours while an LED can continue to operate with reduced efficiency for more than 50,000 hours, 50 times longer than the incandescent bulb.
Figure 3.2 Structural construction of a LED light.
The Advantages of LED are listed bellow-
Efficiency: LEDs emit more light per watt than incandescent light bulbs . Their efficiency is not affected by shape and size, unlike fluorescent light bulbs or tubes.
Color: LEDs can emit light of an intended color without using any color filters as traditional lighting methods need. This is more efficient and can lower initial costs.
On/Off Time: LEDs light up very quickly. A typical red indicator LED will achieve full brightness in under a microsecond . LEDs used in communications devices can have even faster response times.
Dimming: LEDs can very easily be dimmed either by pulse-width modulation or lowering the forward current.
Cool Light: In contrast to most light sources, LEDs radiate very little heat in the form of IR that can cause damage to sensitive objects or fabrics. Wasted energy is dispersed as heat through the base of the LED.
Slow Failure: LEDs mostly fail by dimming over time, rather than the abrupt failure of incandescent bulbs.
Lifetime: LEDs can have a relatively long useful life. One report estimates 35,000 to 50,000 hours of useful life, though time to complete failure may be longer . Fluorescent tubes typically are rated at about 10,000 to 15,000 hours, depending partly on the conditions of use and incandescent light bulbs at 1,000–2,000 hours.
The Disadvantages of LED are given bellow-
High Initial Price: LEDs are currently more expensive, price per lumen, on an initial capital cost basis, than most conventional lighting technologies.
Temperature Dependence: LED performance largely depends on the ambient temperature of the operating environment.
Light Quality: Most cool-white LEDs have spectra that differ significantly from a black body radiator like the sun or an incandescent light. The spike at 460 nm and dip at 500 nm can cause the color of objects to be perceived differently under cool-white LED illumination than sunlight or incandescent sources, due to mesmerism red surfaces being rendered particularly badly by typical phosphor based cool-white LEDs.
Blue Hazard: There is a concern that blue LEDs and cool-white LEDs are now capable of exceeding safe limits of the so-called blue-light hazard as defined in eye safety specifications such as ANSI/IESNA RP-27.1–05: Recommended Practice for Photo biological Safety for Lamp and Lamp Systems.
Electrical Polarity: Unlike incandescent light bulbs, which illuminate regardless of the electrical polarity, LEDs will only light with correct electrical polarity.
Droop: The efficiency of LEDs tends to decrease as one increases current .
Lamp ballast is an electrical device used to control the current provided to the lamp. In most discharge lamps, ballast also provides the high voltage necessary to start the lamp.
Types: The types of ballasts are
Magnetic core-coil ballast
Electronic high frequency Ballast
Rapid start ballast
Instant start Ballast
Programmed start Ballast
Cathode cut out Ballast
Electronic ballasts eliminate flicker, weigh less than magnetic ballast sand operate more quietly.
Ballast Factor: Ballast factor indicates the light output of a lamp when operated with specific ballast relative to the light output of the same lamp when operated with reference ballast.
3.6.3 Lighting Fixture
A lighting fixture is housing for securing lamp(s) and ballast(s) and for controlling light distribution to a specific area. The function of the fixture is to distribute light to the desired area without causing glare or discomfort.
Luminaries: Luminaries refers to a complete lighting system including a fixture, lamp(s) and ballast(s).
Luminaries Efficacy Rating (LER): Luminaire Efficacy Rating is a single metric that expresses luminaire efficacy, the luminaire’s light output divided by the input power. The formula is-
3.6.4 Lighting Controls
Lighting controls include a wide range of technologies that electronically and/or mechanically control the use of lights in a building.
Lighting control systems include programmable timers, occupancy sensors, photo sensors, dimmers, switchable or dimmable ballasts and communications and control systems. In the commercial sector, controls are used to save energy, curtail demand, or tailor the lighting environment to changes in lighting requirements.
Occupancy Sensors: Occupancy sensors, which sense people’s presence in the room by means of infrared or ultrasound signals that detect movement and turn lights off a short time after people leave the space, can save from 20 to 40% of lighting energy in the spaces they control.
Dimmable Systems: Dimmable systems can be set to turn on at different levels in response to changes in occupancy or work demands. Transitional areas from outdoors to indoors (such as tunnel entrances and lobbies) can use dimming or switching systems to provide high light levels during bright day time conditions and lower levels at night.
Integrated Workstation Sensor: An integrated workstation sensor allows users to control not just lighting, but heating and cooling (space temperature)and other electrical equipment (such as plug loads) for individual workstations or spaces
Efficient Lighting Operation: In addition to high quality design and the use of efficient lighting technologies, commissioning and maintenance of lighting system plays important roles in maximizing energy saving.
The commissioning process is necessary because lighting system often do not perform exactly as they were designed to perform. The presence of dirt on a luminary can significantly reduce light output. Group relamping is another process for maintaining high efficiency fluorescent and HID lighting system.
3.6.5 Compact Fluorescent Lamp (CFL)
Compact fluorescent lamps (CFL) use less power to supply the same amount of light as an incandescent lamp. Due to the ability to reduce electric consumption, many organizations have undertaken measures to encourage the adoption of CFLs. Some electric utilities and local governments have subsidized CFLs or provided them free to customers as a means of reducing electric demand. For a given light output, CFLs use between one fifth and one quarter of the power of an equivalent incandescent lamp. One of the simplest and quickest ways for a household or business to become more energy efficient is to adopt CFLs as the main lamp source.
Components of a common compact fluorescent lamp are given bellow
An electronic ballast
Fluorescent lights make their energy in a three-step process:
Electrodes take electrical energy from the power supply and generate moving electrons.
The moving electrons collide with mercury atoms in the tubes to make ultraviolet light.
The white phosphor coating of the tubes converts the ultraviolet light into visible light
Flicker: The first compact fluorescent bulbs flickered when they were turned on because it took a few seconds for the ballast to produce enough electricity to excite the gas inside the bulb.
Harmonic Generation: CFL lights are non-linear electronic load. So it distorts current waveform drawn by it. Thus it generates harmonics.
Design and Application: The primary objectives of CFL design are high electrical efficiency and durability. However, there are some other areas of CFL design and operation that are problematic:
End of Life: In addition to the wear-out failure modes common to all fluorescent lamps, the electronic ballast may fail, since it has a number of component parts. Ballast failures may be accompanied by discoloration or distortion of the ballast enclosure, odors, smoke or flames. The lamps are internally protected and are meant to fail safely at the end of their lives..
Dimming: Only some CF lamps are labeled for dimming control. Using regular CFLs with a dimmer is ineffective at dimming, can shorten bulb life and will void the warranty of certain manufacturers. Dimmable CFLs are available. There is a need for the dimmer switch used in conjunction with a dimmable CFL to be matched to its power consumption range, many dimmers installed for use with incandescent bulbs do not yield acceptable results below 40W, whereas CFL applications commonly draw power in the range 7-20W. The dimming range of CFLs is usually between 20% and 90%.However, in many modern CFLs the dimmable range has been improved to be from 2% to 100%, more akin to regular lights. There are two types of dimmable CFL marketed: Regular dimmable CFL sand "switch-dimmable" CFLs.
Heat: Some CFLs are labeled not to be run base up, since heat will shorten the ballast's life. Such CFLs are unsuitable for use in pendant lamps and especially unsuitable for recessed light fixtures. CFLs for use in such fixtures are available. A CFL will thrive in areas that have good airflow, such as in a table lamp.
Power Quality: The introduction of CFLs may affect power quality appreciably, particularly in large-scale installations. The input stage of a CFL is a rectifier, which presents a non-linear load to the power supply and introduces harmonic distortion on the current drawn from the supply. In such cases, CFLs with low (below 30 percent) total harmonic distortion (THD) and power factors greater than 0.9 should be used.
Infra-red Signals: Electronic devices operated by infra-red remote control can interpret the infra-red light emitted by CFLs as a signal; this limits the use of CFLs near televisions, radios, remote controls, or mobile phones. Fortunately, this only happens when light is produced at the same wavelength as the electronic device signals, which is rare
Iridescence: Fluorescent lamps can cause window film to exhibit iridescence. This phenomenon usually occurs at night. The amount of iridescence may vary from almost imperceptible, to very visible and most frequently occurs when the film is constructed using one or more layers of sputtered metal. It can however occur in non-reflective films as well. When iridescence does occur in window film, the only way to stop it is to prevent the fluorescent light from illuminating the film. Some electronic (but not mechanical) timers can interfere with the electronic ballast in CFLs and can shorten their lifespan .
Lifetime Brightness: Fluorescent lamps get dimmer over their lifetime, so what starts out as an adequate luminosity may become inadequate. In one test by the U.S. Department of Energy of "Energy Star" products in 2003–04, one quarter of tested CFLs no longer met their rated output after 40% of their rated service life.
Ultraviolet Emissions: Fluorescent bulbs can damage paintings and textiles which have light-sensitive dyes and pigments. Strong colors will tend to fade on exposure to UV light. Ultraviolet light can also cause polymer degradation with a loss in mechanical strength and yellowing of colorless products.
Following factors should be kept in mind for achieving higher efficiency of CFL:
CFLs should not be used in the place where lighting is to be used for a very limited duration like in closets and here incandescent bulbs can be considered. It is owing to the fact that frequent on/off cycling affects CFLs and as a result their life span of 10000 hours gets affected.
CFLs should not be used in dimmer switches as it affects the life span of the CFLs.
If the CFLs are to be used with a timer, it is imperative that timer package or manufacturer be consulted before using CFL with a timer as incompatible timer can shorten the life span of the CFLs. CFLs should not be deployed for outdoor usage, if they have to be, then they should be protected or shaded from the external environment. During the nights the outdoor temperatures are less as compared to those inside the rooms, so it can have effect on the longevity of the CFLs. Better would be to check the package and find out whether it can perform in the outdoor conditions as efficiently, before installing them outdoors.
CFLs should not be used as source of lighting in retail areas as they do not provide a focused environment but have a defused ambience. CFLs therefore are better.
220.127.116.11 Comparison with Incandescent Lamps
CFLs are compared with incandescent lamps on the basis of lifespan, heating, cooling and starting time.
Lifespan: The average rated life of a CFL is between 8 and 15 times that of incandescent. CFLs typically have a rated lifespan of between 6,000 and 15,000 hours, whereas incandescent lamps are usually manufactured to have a lifespan of 750 hours or 1,000 hours.
The lifetime of any lamp depends on many factors including operating voltage, manufacturing defects, exposure to voltage spikes, mechanical shock, frequency of cycling on and off, lamp orientation and ambient operating temperature, among other factors. The life of a CFL is significantly shorter if it is turned on and off frequently. In the case of a 5-minute on/off cycle the lifespan of a CFL can be reduced to "close to that of incandescent light bulbs.
CFLs produce less light later in their lives than when they are new. The light output decay is exponential; with the fastest losses being soon after the lamp is first used. By the end of their lives, CFLs can be expected to produce 70–80% of their original light output.
Energy Efficiency: The chart shows the energy usage for different types of light bulbs operating at different light outputs. Points lower on the graph correspond to lower energy use.
For a given light output, CFLs use 20 to 33 percent of the power of equivalent incandescent lam. Since lighting accounted for approximately 9% of household electricity usage in the United States in 2001, widespread use of CFLs could save as much as 7% of total U.S. household usage.
Table 3.1 Electrical power consumption vs. light output CFL and incandescent lamps
|Electrical Power Consumption (W)||Minimum Light Output Lumens (lm)|
Heating and Cooling: If a building's indoor incandescent lamps are replaced by CFLs, the heat produced due to lighting is significantly reduced. In warm climates or in office or industrial buildings where air conditioning is often required, CFLs would reduce the load on the cooling system when compared to the use of incandescent lamps, resulting in savings in electricity, in addition to the energy efficiency savings of using CFLs instead of incandescent lamps. However, in cooler climates in which buildings require heating, the heating system will need to replace the inadvertently generated heat. While the CFLs are still saving electricity, total greenhouse gas emissions may increase in certain scenarios, such as the operation of a natural gas furnace to replace the unintended heating from CFLs running on low-GHG electricity. In Winnipeg, Canada, it is estimated that CFLs will only generate 17% savings in energy when switching from incandescent bulbs, as opposed to the 75% savings that can be expected if there were no heating or cooling considerations .
CFL however has some disadvantages as stated below
Starting Time: Incandescent reach full brightness a fraction of a second after being switched on, although some models take several seconds to reach their rated luminance. As of 2009, CFLs turn on within a second, but many still take time to warm up to full brightness. The light color may be slightly different immediately after being turned on. Some CFLs are marketed as "instant on" and have no noticeable warm-up period but others can take up to a minute to reach full brightness  or longer in very cold temperatures. Some that use a mercury amalgam can take up to three minutes to reach full output .This and the shorter life of CFLs when turned on and off for short periods may make CFLs less suitable for applications such as motion-activated lighting.
Hybrid CFL: From November 2010 a Hybrid CFL as a solution for instant warm up time and brightness is commercially available. A second company announced a similar product to be available during 2011. These products combine a halogen lamp with a CFL. The halogen lights immediately and once the CFL has warmed up the halogen lamp goes out.
Health Issues: According to the European Commission Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) in 2008, the only property of compact fluorescent lamps that could pose an added health risk is the ultraviolet and blue light emitted by such devices. The worst that can happen is that this radiation could aggravate symptoms in people who already suffer rare skin conditions that make them exceptionally sensitive to light. They also stated that more research is needed to establish whether compact fluorescent lamps constitute any higher risk than incandescent lamps .
If individuals are exposed to the light produced by some single-envelope compact fluorescent lamps for long periods of time at distances of less than 20 cm, it could lead to ultraviolet exposures approaching the current workplace limit set to protect workers from skin and retinal damage .
The UV radiation received from CFLs is too small to contribute to skin cancer and the use of double-envelope CFLs "largely or entirely" mitigates any other risks.
18.104.22.168 Efficacy and Efficiency
Because the eye's sensitivity changes with the wavelength, the output of lamps is commonly measured in lumens, a measure of the power of light perceived by the human eye. The luminous efficacy of lamps refers to the number of lumens produced for each watt of electrical power used. A theoretically 100% efficient electric light source producing light only at the wavelength the human eye is most sensitive to would produce 680 lumens per watt.
The typical luminous efficacy of CFLs is 60 to 72 lumens per watt  and that of normal domestic incandescent lamps is 13 to 18 lm/W . Compared to a theoretical 100% efficient lamp (680 lm/W), these figures are equivalent to lighting efficiency ranges of 9 to 11% for CFLs (60/680 to 72/680) and 1.9 to 2.6% for incandescent (13/680 to 18/680).
While CFLs require more energy in manufacturing than incandescent lamps, this embodied energy is offset by their longer life and lower energy use than equivalent incandescent lamps .
The chart below lists values of overall luminous efficacy and efficiency for several types of general service, 120-volt, 1000-hour lifespan incandescent bulb and several idealized light sources. A similar chart in the article on luminous efficacy compares a broader array of light sources to one another.
Table 3.2 Luminous efficacy and efficiency of several types of lighting
|Type||Overall Luminous Efficiency||Overall Luminous Efficacy (lm/W)|
|40 W tungsten incandescent||1.9%||12.6|
|60 W tungsten incandescent||2.1%||14.5|
|100 W tungsten incandescent||2.6%||17.5|
|Ideal black-body radiator at 4000 K||7.0%||46.5|
|Ideal black-body radiator at 7000 K||14%||95|
|Ideal monochromatic 555 nm (green) source||100%||683|
3.7 Effective Use of CFL and Electronics Ballast in Tube Light
If Incandescent Lights are converted with CFL and existing Tube lights having Magnetic ballasts with electronic ballast, then our Lighting bill will reduce by at least 60% or more. Domestic consumption is around 40%. Assuming overall minimum 20% saving for lighting, reduce peak demand or Load shedding by at least 400 MW.
Figure 3.3 Compact fluorescent lamps
Normal incandescent lamps consume more than 90% electricity for heating and 10% for illumination, so avoid it. For lights used more than 4 hours a day, use Fluorescent or Compact Fluorescent lamps (CFL) or Energy Saving Lamps. It will save more than 66% electricity cost. Again incandescent lamps have 1000-hour life and CFL have 6,000-15,000 hours life. Slim tube lights give better light and save electricity.
The following measures if adopted by the Government will save at least 400 MW of electricity at Consumer point, which is at least US$ 533 million from “Generation-transmission-distribution cost”.
CFL Warranty Increase to 2 years: The CFL suppliers claim 6,000-10,000 hours life. Considering 8 hours a day use, it will last for 2-4 years. So it should have at least 2 years warranty.
Poor Power Factor and More Harmonic Distortion in Cheap CFL: Most of the CFL available in country have poor Power factor around 60-70% and more Total Harmonic Distortion (THD). This is harmful when it is used in bulk. As a result savings in electricity is not wholly effective and it has adverse effect on electricity quality and generation. CFL with Poor Power Factor and more total harmonic distortion are discouraged worldwide. The Government should allow only CFL with minimum 90% power factor and THD below 30%.
Disposal of CFL after Full Use: Fluorescent lamps contain mercury, a toxic heavy metal, which may require special disposal, separate from general and household wastes. Mercury poses the greatest hazard to pregnant women, infants and children. Safe disposal required to store the bulb unbroken. A broken fluorescent lamp is more hazardous than a broken conventional incandescent bulb due to the mercury content. Government should ask CFL manufacturer and supplier to arrange safe Recycling facilities for CFL. Consumers should return it to the store from where it is purchased.
Tube Lights-Electronic Ballast vs. Ordinary Ballast: Electronic ballast saves at least 14 watts with same illumination. Only problem voltage fluctuation might damage the electronic ballast. So change all Magnetic ballasts to Electronic ballast
Restriction of Magnetic Ballast: Its import should be banned or discouraged imposing high taxes. But remember, Utilities are to provide better quality electricity (no low of fluctuating voltage)
Garments one of largest consumer of Tube Lights. All Ballasts be replaced by Electronic ballast. They may be given loan for the same.
3.8 Environmental Impact
Lighting loads such as CFLs, incandescent bulbs have some environmental impact. These are
Mercury Content: Compact fluorescent lamps, like all fluorescent lamps, contain small amounts of mercury as vapor inside the glass tubing. Most CFLs contain 3–5 mg per bulb, with the eco-friendly bulbs containing as little as 1 mg . Because mercury is poisonous, even these small amounts are a concern for landfills and waste incinerators where the mercury from lamps may be released and contribute to air and water pollution. In the U.S., lighting manufacturer members of the National Electrical Manufacturers Association (NEMA) have voluntarily capped the amount of mercury used in CFLs. In the EU the same cap is required by the ROHS law.
In areas with coal-fired power stations, the use of CFLs saves on mercury emissions when compared to the use of incandescent bulbs. This is due to the reduced electrical power demand, reducing in turn the amount of mercury released by coal as it is burned. In July 2008 the U.S. EPA published a data sheet stating that the net system emission of mercury for CFL lighting was lower than for incandescent lighting of comparable lumen output. This was based on the average rate of mercury emission for U.S. electricity production and average estimated escape of mercury from a CFL put into a landfill .Coal-fired plants also emit other heavy metals, sulphur and carbon dioxide.
Figure 3.4 Mercury content comparison between CFL and incandescent
Net mercury emissions for CFL and incandescent lamps, based on EPA FAQ sheet, assuming average U.S. emission of 0.012 mg of mercury per kilowatt-hour and 14% of CFL mercury contents escapes to environment after land fill disposal.
In the United States, the U.S. Environmental Protection Agency estimated that if all 270 million compact fluorescent lamps sold in 2007 were sent to landfill sites that this would represent around 0.13 metric tons, or 0.1% of all U.S. emissions of mercury (around 104 metric tons that year) .
3.9 Comparison between Different Lamp Types
Some experiments were done to find out the Luminaire Efficacy Rating (LER) of the lighting loads that are used in the normal lighting fixtures in Bangladesh. Luminaire Efﬁcacy Rating is a singlemetric that expresses luminaire efﬁcacy, the luminaire’s light output divided by the input power. The formula is:
Lighting loads (Incandescent, Fluorescent, CFL)
Variable Voltage controller (Variac)
Magnetic and electronics ballast
Table3.3 Luminaire Efficacy Rating (LER) for incandescent lighting loads
|Lighting Load||Watt(rated)||Watt(actual)||Voltage(V)||Current (A)||Lumen||LER (lm/W)|
|Lighting Load||Watt(rated)||Watt(actual)||Voltage(V)||Current (A)||Lumen||LER(lm/W)|
|Lighting Load||Watt(rated)||Watt(actual)||Voltage(V)||Current (A)||Lumen||LER (lm/W)|
Again a 23 W CFL provides LER of 45.33 lm/W which is 31.83% better than 100 W incandescent lamp. So it is clear that a 23W CFL provides almost same amount of LER as compared to 36 W fluorescent lamp as replacement of a 100 W incandescent lamp.
Figure 3.5 Experimental setup to observe LER of incandescent lights
Figure 3.6 Experimental setup to observe LER of the CFL
Here some observations have been done related to the lighting loads.
3.10.1 Lighting Loads in an Apartment’s Total Load
Let us consider a flat in an apartment building in Dhaka with the following loads
Florescent light – 8
Incandescent light – 5
AC – 2
Freezer – 1
Washing machine – 1
IPS – 1
TV – 1
PC – 1
Other normal day to day equipments
Table 3.6 Power consumption of different loads
|Equipments||Numbers||Power Consumption (W)
||Total Power (W)|
|Desktop Computer and 17" CRT monitor||01||340||340
Power consumed by lighting is 840 watts out of total 8930 watts which is 9.41% of total consumption.
Table 3.7 Compact Fluorescent light (CFL) vs. Incandescent vs. LED Wattages
|Incandescent Lamps (W)||Compact Fluorescent lamps (W)||Light Emitting Diode (W)|
If LED is used instead of Compact Fluorescent light then the total power consumption is 136 watts out of 8226 watts which is 1.65%.
Table 3.8 Percentage of power consumption of different lights
|Lighting Loads||Power Consumption (W)||Percentage of Total Consumption (W)|
|Normal lighting loads||840||9.41|
It is clear from this observation if normal lighting is replaced with CFL percentage of total consumption of lights reduces to 2.88% from 9.41%. Using LED it further reduces to 1.65%. 3.10.2 Power Consumption of a Housing Complex
Normal type of lighting loads can be replaced with CFL and LED to reduce load consumption to a good amount. A housing complex with four buildings each having 40 buildings was observed to analyze the load consumption.
A housing complex = 4 buildings
1 building = 12 storied (12 storied each where ground and 1st floor are for car perking)
Number of flats = 40 (each).So Total number of flats = 4*40 = 160
Table 3.9 Calculation of single flat’s lighting load consumption
|No. of light||Fluorescent||Incandescent||CFL||LED|
|Watt||Total watt||Watt||Total watt||Watt||Total watt||Watt||Total watt|
|1 living room||02||35||70||–||–||16||32||08||16|
|Total power (W)||210||420||196||82|
|Location||No. of lights||Fluorescent||Incandescent||CFL||LED|
||Total watt||Watt||Total watt||Watt||Total watt||Watt||Total watt|
|Stair and lobby||30||35||1050||–||–||16||480||08||240|
|Total power (kW)||17.850||17.040||12.220||5.460|
|Lighting loads||Number of Buildings||Total Lighting Load Power Consumption (kW)||Saving Power Consumption (kW)|
|Fluorescent and Incandescent||4||4*(17.850+17.040) = 139.56||–|
|CFL||4||4*12.22 = 48.88||90.86|
|LED||4||4*5.46 = 21.84||117.72|
3.10.3 Power Consumption of Common Space
In this case we are considering the common place of the housing complex. Common place consists of garage and lobby.
Observation time: from 6:30 pm to 6:30 am.
Total time: 12 hour
Table 3.12 Calculation of lighting loads consumption (in 12 hours, full brightness) of common space
|Place||Fluorescent (200)||Incandescent (50)||CFL (250)||LED (250)|
|Stair and lobby||35||1050||–||–||16||480||08||240|
|Total Consumpt-ion (kW)||13.05||3.68||1.84|
Table 3.13 Comparison of these lighting loads
|Lighting load||Power Consumption (kW)||Power Saving (kW)||Percentage of Saving (%)|
|Fluorescent and Incandescent||13.05|
Another way to reduce the lighting loads power consumption in common place that is hourly basis load distribution. It is observed that from 6-30 pm to 6-30 am in total 12 hours, It does not need to turn on all the lights or if we turn on all the lights then it does not need the same amount of brightness light during this 12 hours. In this case, it indicates that:
Table 3.14 Calculation of power consumption in hourly basis
|Time in hours||No. of hours||Brightness||Fluorescent and Incandescent (kWh)||CFL (kWh)||LED (kWh)|
Table 3.15 Comparison between 12 hours and hourly basis consumption
|Lighting Load||In 12 Hours Energy (kWh)||Hourly Basis Energy (kWh)|
|Fluorescent and Incandescent||156.6||99.18|
The data represents that using CFL saves (156.6 – 44.16) = 112.44 kWh in 12 hours and (99.18 – 27.968) = 71.21 kWh in hourly basis and using LED saves (156.6 – 22.08) = 134.52 kWh in 12 hours and (99.18 – 13.984) = 85.196 kWh in hourly basis than using fluorescent and incandescent
3.10.4 Power Consumption of MIST Tower Building
Another observation was done on MIST tower building to analyze the reduction of consumption replacing fluorescent and incandescent by CFL and LED.
Total floor = 11
Department and Teacher’s room = 7th, 8th, 9th
Class room = 3rd, 4th, 5th, 6th
Lab= ground, 1st, 4th, 6th
Conference room = 2nd, 9th
Multipurpose hall = 10th
Common space = Lobby, stair, wash rooms
Table 3.16 Calculation of power consumption of Tower building
|Floor and space||No. of load||Normal lighting loads (W)||CFL (24W each)||LED
|Fluorescent (35)||Incandescent (100)|
|10||304||268*35 = 9380||36*100 = 3600||7296||2432|
|7,8, 9||120||90*3*35 =9450||30*3*100= 9000||8640||2880|
|3,4,5,6||100||80*4*35= 11200||20*4*100 = 8000||9600||3200|
|1,2||150||130*2*35 = 9100||20*2*100 = 4000||7200||2400|
|Ground||120||100*35 = 3500||20* 100 = 2000||2880||960|
|Common space||320||–||320*100 = 32000||7680||2560|
Figure 3.7 MIST tower building
Table 3.17 Comparison among Normal lighting loads, CFL and LED
|Lighting loads||Power Consumption (kW )||Power Saving (kW)|
|Fluorescent and Incandescent||101.23||–|
The data represents that using CFL saves 57.23% and using LED saves 85.74% power than using fluorescent and incandescent.
A smart meter is usually an electric meter that records consumption of electrical energy in intervals of an hour or less and communicates that information at least daily back to the utility for monitoring and billing purposes .Smart meters enable two-way communication between the meter and the central system. Unlike home energy monitors, smart meters can gather data for remote reporting.
The significant thing about the smart meter is that it removes the cumbersome task of collecting data from utility and from the consumer; and at the same time it makes both parties focus on analyzing data – from the utility’s viewpoint for a more efficient grid operation and from the consumers’ viewpoint for a more energy efficient consumption pattern.
Communication: If the meter is integrated in an automated meter reading system, it must of course be able to communicate with the data management system which is placed on a server either at the utility or at the system provider. In case the utility uses two different providers for meters and system, the meters must be interoperable, in other words they must speak the same language as the system.
The utility can opt for a one-way communication where consumption data are transmitted directly to the utility’s central system; or they can choose two-way communication which gives the utility a comprehensive control of the meter with the possibility of enhanced customer services like the smart disconnect and remote upgrade of software.
The meter itself consists of two hardware parts: a certified and sealed metering construction and a separate module area. The module area gives the meter a flexibility in regard to the various communication media and which system software to interact with.
It is therefore not possible to give a full description of the smart meter because it is customized according to the needs and wishes of the energy distributor. Instead we will on this site list some of the main functions in order to give at least an idea of, what a smart meter can do and how the utility as well as the private energy consumer may benefit from the intelligent residential electricity meter.
Smart disconnect/reconnect: The disconnect/reconnect relay of the smart meter allows the utility to switch off the power remotely and to switch the power back on.
Voltage quality: Voltage levels are measured and recorded providing the energy distributor with valuable information to perform an efficient grid operation.
Tariffing: Using different tariffs is another way of leveling out the power demand and reducing peaks during the day. Cheaper tariffs at other times than peak loads in the morning and in the afternoon will help the utilities in shortening the so called ‘spinning reserve’ (the spinning reserve is the extra capacity needed in case of an immediately occurring load demand; of course the spinning reserve is wasted energy).
Energy awareness: One of the great achievements about the smart meter is that it makes it a lot easier for the consumer to follow his energy consumption. By means of data logging functionalities the consumer can get access to stored data and compare the consumption from day to day or month to month. One can even watch live the consumption curve declining as he switches off the electrically heated towel rack.
Figure 4.1 Display of the smart meter showing the power consumption
On one side the physical presence of the utility at the customer’s residence almost totally vanishes with the introduction of the smart meter; on the other side the smart meter effectively brings energy awareness to the consumer giving the utility an even stronger presence in the mind of the consumer as a customer of the utility’s services.
Smart metering generally involves the installation of an intelligent meter at residential customers and the regular reading, processing and feed back of consumption data to the customer. A smart meter has the following capabilities:
Real-time or near-time registration of electricity use and possibly electricity generated locally e.g. in case of photovoltaic cells;
Offering the possibility to read the meter both locally and remotely (on demand);
Remote limitation of the throughput through the meter (in the extreme case cutting of the electricity to the customer)
Interconnection to premise-based networks and devices (e.g. distributed generation)
Ability to read other, on-premise or nearby commodity meters (e.g. gas, water)
4.2 Consumer Engagement and Energy Saving
Smart meters could lead to an eventual revolution in information about individual energy use, offering scope for new tariffs and new ways to provide feedback to householders, including billing, displays and other methods. It may be many years before the full extent of this data-revolution becomes apparent, but in the meantime smart meters will be central in improving consumer engagement with their energy use.
Smart meters are a tool, helping to enable behavior change and demand reduction. If the potential benefits of smart meters are to be fully realized, it is absolutely essential that there is a well-resourced body providing independent consumer information, advice and education on how to use the information households are given and a powerful campaign designed to encourage those with wasteful energy use to use it more wisely. It is important that any consumer information and campaign is ongoing and well targeted using social marketing to help change behavior and encourage demand reduction. Messages should be tailored and targeted to different consumer segments maximizing the likelihood of success.
If the potential benefits of smart meters are to be fully realized, consumer information, advice and education are essential.
4.3 Data Protection, Security and Interface with Home Networks
Smart meters may not transmit the customer’s name or address, but it will involve transmitting personal data probably through the use of a meter point number (similar to an IP address), which can be associated with a person. The information that smart meters will transmit from the customer to the supplier includes:
Payment details for prepayment meter customers
From the energy supplier to the consumer they will transmit:
Data – such as change of tariff;
A change in functionality – such as credit to prepayment
Information – such as energy saving messages, notice of service disruptions and marketing messages
Interference with Home Wireless Networks: The potential for communications between the smart meter and display (and gas and electricity meters in linked solutions) to interfere with an existing home wireless network. This may mean a lot of work with such households to reassure them that they won’t have problems. This may be easier to address in the competitive rather than franchise model.
Apart from the home networks issue noted above, the model adopted for roll-out of smart meters will make no difference to data protection and security – the law will apply equally and systems to protect data will be similar. Under a franchise model, data will be accessed by franchisee and the supplier. Under a competitive model, although in theory it could all stay with the energy supplier, in practice some, if not all energy suppliers, will contract out so there will also be two organizations involved.
4.4 Remote Switching and Disconnection by Smart Meter
Remote switching and disconnection is one of very significant applications smart meters. Following the signature of load current curve, smart meter can operate itself to disconnect the supply if the demand exceeds the allotted load. The sensitivity of smart meters must be set such that it does not operate for a little instance signature of high current as it can be caused by commencement of motors used for household works. Depending on the agreed specification, smart meters should enable energy suppliers to remotely:
Switch between credit and prepayment
Disconnect supply without visiting premises
Reduce the load (load limiting) so the customer could just use lights and the fridge (for example) as an alternative to disconnection.
The University of Hong Kong has commenced research in load signature for some years . Smart metering is a new extension of the study.
A Smart Meter System works as the mediator between power system and final loads. It dialogues with the home manager to recommend control and management of load operation in respect of system condition. Through contractual terms for “forward operation” and quotation for “spot operation”, the smart meter may initiate the voluntary participation of consumers in power quality. The operation may include
Hybrid changeover and
The smart meter can also be developed as a data-link to convey messages in a bidirectional manner. The consumer sends connected-load signatures information to the supplier, and the supplier studies similar and relevant signatures for artificial-intelligence, then gives advices to the consumer.
4.4.1 Load Signature
Knowledge of electric load signatures is the foundation of practical technologies for load monitoring, which involves the identification of an electric appliance and the determination of its operating state. Such knowledge can provide benefits to utilities, customers, appliance manufacturers and other stakeholders.
This system focuses on the two core components of these approaches:
Methods to measure and represent load characteristics
The development of signal processing techniques and estimation algorithms for signal filtering, signal disaggregation and load recognition.
Many approaches may be useful to understanding load signatures, including (a) non-intrusive load monitoring (NILM); (b) echo-resonance load monitoring (ERLM) ; (c) sign-up load registration (SULR) . In a NILM system, it is not necessary to install sensors in individual load. A past example of NILM system (MIT 1980s) measured aggregate current and voltage at the metering panels and processed these signals to differentiate and identify individual loads.
4.4.2 Main Factors for Load Signature Characterization
In this study the input current of each load provides load signature information. The 50Hz voltage and current waveforms were captured at a high sampling rate of 50 kHz per channel which allows us to analyze appliances through raw waveforms in addition to the traditional electrical measurements. The voltage of the ac mains is not purely sinusoidal; in this study it has a (maximum) THD of 2.83% and a maximum voltage amplitude deviation of ~8.1V, limiting the maximum error to 3.68%.
The following factors of the load current are important to characterize each type of electronic/electric loads commonly used for office and domestic applications: Current is measured during start-up transient and steady state; this waveform and its envelope are analyzed, as is the voltage-current trajectory under start-up and steady-state conditions
Start-up current and its envelope
Steady-state current waveform
The voltage-current trajectory under start-up and steady-state conditions
Classification: The complexity of the classification cannot be fully explained in a digest. But some brief examples of load signature classification are given here as examples.
Type 1: Passive and Active resistive loads: These loads behave like resistors. Examples of passive resistive loads are heating equipment such as hair dryers, kettles and heaters. Examples of active resistive loads are systems with front-end PFC circuits that operate at near-unity power factors. In general, the steady-state V-I trajectory (Table 2) of passive resistive load is a straight line, whilst that of an active resistive load is a “zig-zag” curve along a straight line. The “zig-zag” is due to the switching ripple of the PFC.
Type 2: Rectifier Loads: This group of loads usually draws current pulses in steady state. The front-end circuits are usually diode-rectifier loaded with an output capacitor or a valley-fill circuit.
Type 3: Motor Loads: This group of loads is commonly used in office/domestic applications. Examples are electric motor loads such as refrigerators and fans. They are inductive loads and tend to have a characteristic start-up process (due to the accelerating speed of the motors).
Type 4: General Inductive loads: Unlike Type 3, Type 4 loads do not necessarily have repeatable start-up behavior. Examples are magnetic ballasts for lighting devices. The igniter of the ballast consists of a bimetallic switch(s) which operates differently at different times, depending on the initial voltage and thermal conditions.
The current and voltage waveforms in their steady states are observed on the oscilloscope Figure 4 shows some examples of waveform of the tested appliances. From the observation, the voltage waveform, as shown in Figure 4.2 (a), is unchanged for different appliances; the disturbance by the loads is insignificant. However, the current waveforms, Figures 4.2 (b)-(g), are distinctive for different appliances, and represent the load signatures. The current waveforms of different kinds of lights are shown in Figure 4.2 (b) – (d). Figure 4.2 (e) and (f) show the current waveforms of a laser printer when in stand-by and printing modes. The printer is another nonlinear appliance. Clearly, the same appliance has different current waveforms in different operation states: when the laser printer changes to printing mode, its current waveform shape changes – a good example of the characteristic operational patterns in the current waveform of some appliances. Figure 4.2 (f) shows a portion of the current waveform when the printer is printing.
The current of the above appliances operating at the same time are also measured, and the current waveform is shown in Figure 4.2 (g). The combined waveform is the superposition of the waveforms of individual appliances from Figure 4.2 (b) to (e) .
Figure 4.2 (a) Voltage
Figure 4.2 (b) Current of energy saving light bulb
Figure 4.2 (c) Current of fluorescent lamps with conventional ballast
Figure4.2 (d) Current of fluorescent lamps with electronic ballast
Figure 4.2 (e) Current of laser printer when in standby mode
Figure 4.2 (f) Current of laser printer when printing
Figure 4.2 (g) Aggregate current of the appliances from (b) to (e)
Figure 4.2 Examples of waveforms of some appliances. (a) Voltage waveform of all appliances, the scale is 200V/Division. (b) – (g) Individual appliance current waveforms and aggregate current waveform, the scale is 2A/Division
Rectifier loads: Examples- energy-saving light bulb, computer
Figure 4.3 Rectifier loads signature
Motor loads: Examples: fan, vacuum cleaner, refrigerator
Figure 4.4 Motor load signature
4.5 New Technologies of Smart Metering
Together with new tariffs, smart meters will enable a range of new services. Some may be available relatively quickly, some in the longer term as energy suppliers seek to extend and differentiate their service offerings. Some likely developments are as follows:
Electricity and gas sold in combination with other services: Such as broadband or cable packages, perhaps for communications, entertainment and fuel – or with banking, insurance or home-security services. New combined packages, many of which may be e-account based, could be a growth marketing area.
Smarter appliances and smarter homes: Together with smart meters, a variety of in-home wireless controls and sensors may be installed to create smarter homes. This includes individual appliance switching, load-control and thermostat-control . Consumers want better understanding of, and control over, the consumption of individual appliances. In home networks with micro-processor controls could enable this.
Automated and demand-side control: New tariffs facilitated by smart meters, together with new developments in automated control of certain household appliances, (for example, gas boiler controls and thermostats and water heaters) are likely to become available. For the future, time of use tariffs facilitated by smart meters could also be important in helping to manage any major increase in electrical load which may result from a radical increase in electric vehicle use.
Additional safety features: Every year there are a small number of electrical fatalities. Smart meters could facilitate additional safety features. For example, a switch with micro-processor controls could provide a very sensitive residual current device facility helping to detect earth leakage.
Energy services packages: Energy services packages could combine smart meters and energy-saving tariffs with for example, load-management devices, installation of energy efficiency and insulation measures and perhaps heat-pumps or other micro-generation.
Metering for micro-generation: Import and export capability is likely to become a standard functionality of all electricity smart meters without material incremental cost, and could enable householders to benefit from the electricity they export. Micro-generation metering will also provide better information to the network operators about distributed generation activity in their area.
Smart water metering: Smart energy meters will mean that an external communications interface is installed in most homes in effect a smart-hub probably the electricity meter. This would make it feasible to transmit data from an electronic water meter (where installed) by in-home radio-link to the electricity meter and route it onward to the water company.
4.6 Zigbee Protocol in Smart Metering
Advanced Metering Infrastructure (AMI) which holds the concept of smart metering includes the cost savings and environmental benefits it can provide. It then looks at how ZigBee fits into this picture, and the ways in which ZigBee (together with its Smart Energy application profile) is ideally suited for the development, delivery and on-going support of AMI.
AMI encompasses many services and appliances within the home and workplace, all of which need to be able to communicate with one another. Therefore, open standards architecture is essential.
Open standards provide true interoperability between systems, flexible communications choices, and competition and innovation from third-party technology providers for applications not currently envisioned.
In countries where consumers are able to switch between energy a provider, having a common infrastructure helps to avoid waste, create efficiencies, lower consumer costs, and ensure competition.
Having open standards also ensures that utilities can choose the best-in-class vendor for all types of AMI components from the meter itself, to software, smart appliances, and in-home displays and have all components work together. Open standards also help to future proof investments made by both utilities and consumers. If communication network pricing or technology change, the AMI components can easily switch to a new network, as long as it supports the open standards used for communications.
Using an open protocol typically reduces costs in implementing: there are no interoperability problems to solve, and manufacture costs tend to be lower.
It would be in the best interest of promoting energy efficiency if there was just one common protocol. A single standard to communicate with devices in a home area network is advisable and in such case non-proprietary ZigBee protocol is suggested.
ZigBee was developed by the ZigBee Alliance, a world-wide industry working group that developed standardized application software on top of the IEEE 802.15.4 wireless standard. ZigBee is designed specifically for monitoring and control of appliances and applications that exist in our daily lives. The monitoring devices need to be able to communicate with each other quickly and needs little maintenance. Its low power usage makes ZigBee ideal for AMI. Batteries in devices will last for years rather than just the days or hours achieved using some other standards-based technologies. ZigBee is designed to be easy to incorporate into a wide range of devices, which makes it ideal for a system that includes smart meters, and potentially other components into the future.
ZigBee-enabled meters form a complete mesh network so they can communicate with each other and route data reliably. And the ZigBee network can be easily expanded as new homes are built or new services need to be added.
The ZigBee Alliance has recently announced its “Smart Energy” public application profile (January 2008). ZigBee Smart Energy offers utility companies a global open standard for implementing secure, easy-to-use wireless home area networks for managing energy. The profile also offers product manufacturers access to a burgeoning green marketplace by establishing a standards-based technology for new products designed to enhance energy management and efficiency by consumers everywhere.
ZigBee application profiles are designed to provide seamless integration within the network, so that the Smart Energy profile can be used with ZigBee’s other public application profiles, which include Home Automation, Commercial Building Automation and Industrial Automation. This provides a single integrated solution for controlling energy demand and supply both at home and in the workplace.
4.7 Smart Grid Interaction with Smart Meter
An electrical grid is not a single entity but an aggregate of multiple networks and multiple power generation companies with multiple operators employing varying levels of communication and coordination, most of which is manually controlled. Smart grids increase the connectivity, automation and coordination between these suppliers, consumers and networks that perform either long distance transmission or local distribution tasks.
A smart grid is a means for consumers to change their behavior around variable electric rates or participate in pricing programs designed to ensure reliable electrical service during high-demand conditions. Historically, the intelligence of the grid in North America has been demonstrated by the utilities operating it in the spirit of public service and shared responsibility, ensuring constant availability of electricity at a constant price, day in and day out, in the face of any and all hazards and changing conditions. A smart grid incorporates consumer equipment and behavior in grid design, operation, and communication. This enables consumers to better control “smart appliances” and “intelligent equipment” in homes and businesses, interconnecting energy management systems in “smart buildings” and enabling consumers to better manage energy use and reduce energy costs. Advanced communications capabilities equip customers with tools to take advantage of real-time electricity pricing, incentive-based load reduction signals, or emergency load reduction signals.
There is marketing evidence of consumer demand for greater choice. A survey conducted in the summer of 2007 interviewed almost 100 utility executives and sought the opinions of 1,900 households and small businesses from the U.S., Germany, Netherlands, England, Japan and Australia . And as already noted, in the UK where the experiment has been running longest, 80% have not changed their utility provider when given the choice.
Proponents assert that the real-time, two-way communications available in a smart grid will enable consumers to be compensated for their efforts to save energy and to sell energy back to the grid through net metering. By enabling distributed generation resources like residential solar panels, small wind proponents assert that the smart grid will spark a revolution in the energy industry by allowing small players like individual homes and small businesses to sell power to their neighbors or back to the grid. Many utilities currently promote small independent distributed generation and successfully integrate it with no impact.
In spite of huge inequilibrium in generation and demand we still certainly have a huge opportunity to get rid of this electrical power crisis through implementation of new advanced technologies and some behavior change in consumption of our mass people.
In the year 2004 about 32% households have electricity connection and approximately 4% households have natural gas supply. The Rural Electrification Board (REB) network covers approximately 40% of rural Bangladesh, but within the grid covered area only 40% households have electricity connection about 32 percent population has access to electricity.
Even though at present Bangladesh is in an early stage of real state housing development. The industrial base will be fairly large in 15 to 20 years time because growth rate of this sector is fairly high. This implies that a lot of residential infrastructure will be built in the next two decades. Therefore, it may be more effective to target those buildings that will be built in the next two decades to make them energy efficient and inefficient buildings can easily be forced to change using regulatory measures.
Lighting constitutes 70 percent of the evening peak of electrical load. The evening peak of electricity demand constitutes mainly lighting load in garment industries and residential sectors. Energy efficiency can be achieved in these industries by introducing energy efficient devices (electronic starter) and efficient fluorescent lamps.
From this study we conclude that the following proposals will contribute towards an energy efficient technically sound society-
(1) Lighting being the heaviest load there should be huge awareness created for using energy efficient lighting loads like LED, CFL. People should be more aware of using this national wealth for the betterment of future generation.
(2) Smart metering should be implemented to ensure proper use of electrical power.
(3) From the present instance every building should be built with its own generation ability for certain amount and smart metering should be implemented changing the consumption behavior.
(4) In case of implementing the idea of zero energy home the architectural design has to be very specific and design should ensure the natural ventilation so that the home gets natural lighting and cooling which can reduce the consumption of electricity to a great extent.
(5) Trough smart metering the different billing criterion can be implemented. Peak and off peak hour billing can have a different price. Through the high peak hour billing rate the consumer can be discouraged to use heavy and unnecessary loads during the peak hours when there is huge difference between generation and demand.
(6) Trough smart metering each consumer can have a fixed load sanction during peak and off peak hour. Through sanctioning load consumption behavior can be greatly changed such as if the consumer exceeds load sanctioned for he can be out service for a certain period of time.
(7) Day light saving can be a very relevant option of saving electrical energy.
(8) A general practice in our country now-a- days is using instant power supply (IPS) during load shedding which gives apparently 40% output; using smart meter if we can restrict power consumption then we will be able to discourage this huge wastage of power through IPS.
(9) Renewable energy can be highly encouraged for the future power plants and for individual generation system.
(10) The interaction with grid through smart meter can bring about a huge change in the consumption behavior, generation and reserve.
5.2 Further Work
To ensure the efficient utilization of the electrical energy in existing residential and commercial zone an Energy audit can be taken as a further goal. An audit can help assess how much energy a home uses and evaluate what measures that can be taken to improve efficiency.
An energy audit of a home may involve recording various characteristics of the building envelope including the walls, ceilings, floors, doors, windows and skylights. For each of these components the area and resistance to heat flow is measured or estimated. The leakage rate or infiltration of air through the building envelope is of concern, both of which are strongly affected by window construction and quality of door seals such as weather stripping. The goal of this exercise would be to quantify the building's overall thermal performance.
Some of the greatest effects on energy use are user behavior, climate and age of the home. An energy audit may therefore include an interview of the homeowners to understand their patterns of use over time. The energy billing history from the local utility company can be calibrated using heating degree day and cooling degree day data obtained from recent, local weather data in combination with the thermal energy model of the building. Advances in computer-based thermal modeling can take into account many variables affecting energy use.
Now with energy audit implementation, the existing industrial and residential zone can be modified to ensure power consumption in an efficient way.
 EIU, 2005, Bangladesh: country profile, The Economist Intelligence Unit (EIU), London
 Islam, 2003 M. Islam, Energy efficiency potentials in the power sector of Bangladesh. 2003 Renewable Energy Information Network (REIN), Local Government Engineering Department (LGED), Bangladesh (2003).
 CRC Handbook of Mechanical Engineering, 2nd Ed., 2005, Chapter 9: Air Conditioning and
Refrigeration, Herbert A. Ingley and Shan K Wang
 Handbook of Heating and Air Conditioning, 2002, ASHRAE Handbook: Refrigeration by Robert Parson, American Society of Heating, Refrigeration and Airconditioning.
 Handbook of Heating, Ventilation and Air Conditioning, Jan F. Kreider, ed., 2001, CRC Press, Boca Raton, FL.
"Definition of a Zero Net Energy Community".NREL:Technical report NREL/TP-7A2-46065
 "A swamp cooler cools air by evaporation", WonderQuest Weekly Q and A science column.
 "How A Tankless Gas Water Heater Works".www.rinnai.us. http://www.rinnai.us/tankless-water-heater/learn-about- tankless/how-tankless-works/. Retrieved 2010-03-29.
 "Passive Solar Design for the Home".EERE:Technical report DOE/GO- 102001-1105 F5121
 "The Complete Guide to Green Building and Remodeling Your Home" by Martha Maeda;Atlantic publishing company.
 "U-factor, SHGC, CR, VT, Air Infiltration – What does this stuff mean?" by David Paulus, PhD., P.E.
 Hill, Russ (1999). Coated Glass Applications and Markets. Fairfield, CA: BOC Coating Technology. pp. 1–4.
 Carmody, John, Stephen Selkowitz, Lisa Heschong (1996). Residential windows : a guide to new technologies and energy performance (1st. ed. ed.). New York: Norton.
 "Introduction to Solar Electricity and Residential Solar Panels-Alte".Altestore.com.Retrieved september 3,2010.
 Ashden Awards. "Micro-hydro". http://www.ashdenawards.org/micro- hydro. Retrieved 2009-06-29.
 Lam H.Y., Fung G.S.K., and Lee W.K., "A Novel Methodto Construct Taxonomy of Electrical Appliances Based on Load Signatures" IEEE Transactions on Consumer Electronics, May 2007
 Fung Kwok Bong, “Simulation of a Proposed Architecture in Smart Electricity Metering”, 2007, research project of Department of Electrical and Electronic Engineering of The University of Hong Kong.
 Leading luminaries. Cabinet Maker [serial online]. December 17, 2004;(5419):21-22. Available from: Business Source Premier, Ipswich, MA.
 Khan N, Abas N. Comparative study of energy saving light sources. Renewable and Sustainable Energy Reviews [serial online].
 How to power an ENERGY-EFFICIENT LIGHT. Machine Design [serial online]. June 19, 2008;80(12):51-53. Available from: Academic Search Premier, Ipswich, MA.
1. ASHRAE. 1999. ASHRAE/IESNA Standard 90.1-1999, Energy Standard for Buildings Except
Low-Rise Residential Buildings, I-P Edition, American Society of Heating, Refrigerating and
Air-Conditioning Engineers, Inc., approved by the ASHRAE Standards Committee June 19, 1999 and by the ASHRAE Board of Directors June 24, 1999, Atlanta, GA.
2- National Lighting Product Information Program, Lighting Research Center, Troy, New York. http://www. lrc.rpi.edu/programs/NLPIP/index.asp
 "Why does my compact fluorescent light bulb flicker or appear dim when I first turn it on?". Compact Fluorescent Light Bulb (CFL) FAQs. GE Lighting. Retrieved 2009-06-15.
 Performance Standard and Inspection Methods of CFL
 Charles P. Halsted (March 1993). "Brightness, Luminance, and Confusion". Information Display. Naval Air Warfare Center Warminster, PA. Retrieved 2007-10-07.
 (PDF) DOE Solid-State Lighting CALiPER Program Summary of Results: Round 7 of Product Testing.. U.S. Department of Energy. February 2009.
 "GE lighting catalog".
 "Solid-State Lighting: Comparing LEDs to Traditional Light Sources".
 "Data Sheet – HLMP-1301, T-1 (3 mm) Diffused LED Lamps". Avago Technologies, Inc.. Retrieved 2010-05-30.
 "Solid-State Lighting: Lifetime of White LEDs".
 Department of Energy
 The Led Museum
 James A. Worthey. "How White Light Works". LRO Lighting Research Symposium, Light and Color. Retrieved 2007-10-06.
 E. Hecht (2002). Optics (4 ed.). Addison Wesley. p. 591. ISBN 0195108183.
 "Blue LEDs: A health hazard?". texyt.com. January 15, 2007. Retrieved 2007-09-03.
 "Light Impacts: Science News". Sciencenews.org. May 27, 2006.
 (PDF) Visibility, Environmental, and Astronomical Issues Associated with Blue-Rich White Outdoor Lighting.. International Dark-Sky Association. May 4, 2010.
 A. A. Efremov, N. I. Bochkareva, R. I. Gorbunov, D. A. Larinovich, Yu. T. Rebane, D. V. Tarkhin, and Yu. G. Shreter, (2006). "Effect of the joule heating on the quantum efficiency and choice of thermal conditions for high-power blue InGaN/GaN LEDs". Semiconductors 40 (5): 605. doi:10.1134/S1063782606050162.
 FAQs: Compact Fluorescent: GE Commercial Lighting Products
 "U.S. Household Electricity Report". U.S. Energy Information Administration. 2005.
 "Efficient lighting equals higher heat bills: study". CBC News. 2009-03-04.
 "Why does my compact fluorescent light bulb flicker or appear dim when I first turn it on?". Compact Fluorescent Light Bulb (CFL) FAQs. GE Lighting. Retrieved 2009-06-15.
 "GE Lighting Frequently Asked Questions – Compact Fluorescent (CFL): 4. Can I use a CFL in applications where I will be turning the lights on/off frequently?". Retrieved 2007-04-13.
 "I've noticed some CFLs need a few minutes to warm up, or reach full brightness…". Customer Help FAQ. Energy Star. Retrieved 2009-06-15.
 "Why does it take time for CFL bulbs to come up to full brightness?". Efficient Lighting FAQs. City of Fort Collins. Retrieved 2009-06-15.
 "Energy-Saving Lamps and Health". GreenFacts site. Retrieved 2009-06-10.
 Keefe, T. J. (2007). "The Nature of Light". Community College of Rhode Island. Retrieved 18 September 2010.
 "Conventional CFLs". Energy Federation Incorporated. Retrieved 18 September 2010.
 Compact Fluorescent Light Bulbs – A Tale From Dust to Dust retrieved June 15, 2008.
 http://americanhistory.si.edu/lighting/20thcent/invent20.htm#in4 Inventing 9 Modern Electric Lamps, retrieved 2010 April 30
 "Mercury Content Information Available for Lamps on the 2003 New Jersey Contract T-0192". Archived from the original on 2005-12-30. http://web.archive.org/web/20051230010537/http://www.informinc.org/fact_P3NJlampcontract.php. Retrieved 2007-05-15.
 "Canada-Wide Standard for Mercury-Containing Lamps" (PDF). 2001. http://www.ccme.ca/assets/pdf/merc_lamp_standard_e.pdf. Retrieved 2007-03-23.
 "Frequently Asked Questions Information on Compact Fluorescent Light Bulbs (CFLs) and MercuryJune2008".2008.http://www.energystar.gov/ia/partners/promotions/change_light/downloads/Fact_Sheet_Mercury.pdf. Retrieved 2008-08-31.
 "Mercury in Fluorescent Lamps". FAQ. Energy Federation Incorporated. http://www.efi.org/factoids/mercury.html. Retrieved 2009-07-02.
 "NEMA Lamp Companies Announce Commitment to Cap CFL Mercury Content". http://www.nema.org/media/pr/20070313a.cfm. Retrieved 2007-03-23.
 Compact Fluorescent Bulbs and Mercury: Reality Check. Popular Mechanics, 11 June 2007.
 "Frequently Asked Questions, Information on Proper Disposal of Compact Fluorescent LightBulbs(CFLs)"(PDF).http://www.energystar.gov/ia/partners/promotions/change_light/downloads/Fact_Sheet_Mercury.pdf. Retrieved 2007-03-19.
http://www.energystar.gov/ia/partners/promotions/change_light/downloads/Fact_Sheet_Mercury.pdf Frequently Asked Questions Information on Compact Fluorescent Light Bulbs (CFLs) and Mercury July 2008, accessed 2009 Dec 22
 What are the mercury emissions caused by humans? Do CFLS that wind up in a landfill contribute to these emissions? retrieved January 5, 2009
http://www.csa.ca/cm/ca/en/news/article/new-household-light-standard-addresses-consumer-concerns New household lamp standards, discusses co-ordinated U.S., Mexico and Canada standard UL 1993, retrieved 2009 Dec 3
 Lam H.Y., Fung G.S.K., and Lee W.K., "A Novel Methodto Construct Taxonomy of Electrical Appliances Basedon Load Signatures" IEEE Transactions on Consumer Electronics, May 2007.
 Fung Kwok Bong, “Simulation of a Proposed Architecture in Smart Electricity Metering”, 2007, research project of Department of Electrical and Engineering of The University of Hong Kong.
 C.M. Ho, W.K. Lee, and Y.S. Hung, “Signature Representation of Underground Cables and its Applications to Cable Fault Diagnosis,” Proc. of IEE Int. Conf. on Advances in Power System Control, Operation and Management, Dec, 1993, pp.861-865
 G.P. Hanke, and D. Very, “Electric Load Monitoring and Control in the Domestic Environment,” Proc. of IEEE Conf. on Instrumentation and Measurement Technology, vol.2, May 10-12, 1994, pp.560-562 .
 2005 IEEE PESC (Power Electronics Specialist Conference), 12-18 Jun 2005, Brazil.
 Energy and Utilities, 2007 IBM Global Residential/Small Business Consumer Survey.