English project on energy efficiency

ENERGY EFFICIENCY

There can be economy only

where there is efficiency.

Slide Name Slide No

1 ENERGY? 3

2 HISTORY OF ENERGY 4

3 FORMS OF ENERGY 6

4 ENERGY EFFICIENCY 7

5 EFFICIENT ENERGY USE 9

6 THANK YOU 18

Table of Contents

ENERGY?

What is Energy?

Energy and work occupy an important part of our ordinary life and areamong the most important topics in physics. Energy in physics is definedas the ability to do work.

However, it is clear that energy is always an indispensable prerequisitefor performing mechanical work, and the concept has great importancein natural science. The natural basic units in which energy is measuredare those used for mechanical work; they always are equivalent to a unitof force multiplied by a unit of length. Other equivalent units for energyare mass units multiplied by velocity units squared.

HISTORY OF ENERGY

The word energy derives from the Greek word energeia, which possibly appears for thefirst time in the work of Aristotle in the 4th century BCE.The concept of energy emerged out of the idea of vis viva (living force), which GottfriedLeibniz defined as the product of the mass of an object and its velocity squared; he believedthat total vis viva was conserved. To account for slowing due to friction, Leibniz theorizedthat thermal energy consisted of the random motion of the constituent parts of matter, aview shared by Isaac Newton, although it would be more than a century until this wasgenerally accepted.

In 1807, Thomas Young was possibly the first to use the term "energy" instead of vis viva, inits modern sense. Gustave-Gaspard Coriolis described "kinetic energy" in 1829 in itsmodern sense, and in 1853, William Rankine coined the term "potential energy".The law of conservation of energy, was first postulated in the early 19th century, and appliesto any isolated system.

According to Noether's theorem, the conservation of energy is a consequence of the factthat the laws of physics do not change over time. Since 1918 it has been known that the lawof conservation of energy is the direct mathematical consequence of the translationalsymmetry of the quantity conjugate to energy, namely time.

It was argued for some years whether energy was a substance (the caloric) or merely aphysical quantity, such as momentum. In 1845 James Prescott Joule discovered the linkbetween mechanical work and the generation of heat. This led to the theory of conservationof energy, and development of the first law of thermodynamics.

Finally, William Thomson (Lord Kelvin) amalgamated these many discoveries into the lawsof thermodynamics, which aided the rapid development of explanations of chemicalprocesses by Rudolf Clausius, Josiah Willard Gibbs, and Walther Nernst. It also led to amathematical formulation of the concept of entropy by Clausius and to the introduction oflaws of radiant energy by Jožef Stefan.

FORMS OF ENERGY

KINETIC ENERGYPOTENTIAL ENERGYRADIANT ENERGYMASS ENERGYELECTRIC ENERGYGRAVITATIONAL ENERGYHEAT ENERGYMAGNETIC ENERGYMECHANICAL ENERGYNUCLEAR ENERGY

ENERGY EFFICIENCY

Energy efficiency is "using less energy to provide the same service".There are other definitions, but this is a good operational one.The best way to understand this idea is through examples:When you replace a single pane window in your house with an energy-efficient one, the new window prevents heat from escaping in the winter, so you save energy by using your furnace or electric heater less while still staying comfortable. In the summer, efficient windows keep the heat out, so the air conditioner does not run as often and you save electricity.When you replace an appliance, such as a refrigerator or clothes washer, or office equipment, such as a computer or printer, with a more energy-efficient model, the new equipment provides the same service, but uses less energy. This saves you money on your energy bill, and reduces the amount of greenhouse gases going into the atmosphere.Energy efficiency is not energy conservation.Energy conservation is reducing or going without a service to save energy.

For example: Turning off a light is energy conservation. Replacing an incandescent lamp with a compact fluorescent lamp (which uses much less energy to produce the same amount of light) is energy efficiency.

Both efficiency and conservation can reduce greenhouse gas emissions.

EFFICIENT ENERGY USE

Efficient energy use, sometimes simply called energy efficiency,is the goal to reduce the amount of energy required to provideproducts and services. For example, insulating a home allows abuilding to use less heating and cooling energy to achieve andmaintain a comfortable temperature. Installing fluorescentlights or natural skylights reduces the amount of energy requiredto attain the same level of illumination compared with usingtraditional incandescent light bulbs. Compact fluorescentlights use one-third the energy of incandescent lights and maylast 6 to 10 times longer. Improvements in energy efficiency aremost often achieved by adopting a more efficient technology orproduction process.

There are various motivations to improve energy efficiency.Reducing energy use reduces energy costs and may result in afinancial cost saving to consumers if the energy savings offsetany additional costs of implementing an energy efficienttechnology. Reducing energy use is also seen as a solution to theproblem of reducing emissions.

According to the International Energy Agency, improvedenergy efficiency in buildings, industrial processesand transportation could reduce the world's energyneeds in 2050 by one third, and help control globalemissions of greenhouse gases.

Energy efficiency and renewable energy are said to bethe twin pillars of sustainable energy policy and are highpriorities in the sustainable energy hierarchy. In manycountries energy efficiency is also seen to have a nationalsecurity benefit because it can be used to reduce the levelof energy imports from foreign countries and may slowdown the rate at which domestic energy resources aredepleted.

Energy efficiency has proved to be a cost-effectivestrategy for building economies without necessarilyincreasing energy consumption. For example, the stateof California began implementing energy-efficiencymeasures in the mid-1970s, including building code andappliance standards with strict efficiency requirements.During the following years, California's energyconsumption has remained approximately flat on a percapita basis while national U.S. consumption doubled. Aspart of its strategy,

California implemented a "loading order" for new energy resources that puts energyefficiency first, renewable electricity supplies second, and new fossil-fired power plantslast.

Lovins' Rocky Mountain Institute points out that in industrial settings, "there areabundant opportunities to save 70% to 90% of the energy and cost for lighting, fan, andpump systems; 50% for electric motors; and 60% in areas such as heating, cooling, officeequipment, and appliances. In general, up to 75% of the electricity used in the U.S. todaycould be saved with efficiency measures that cost less than the electricity itself. The sameholds true for home-owners, leaky ducts have remained an invisible energy culprit foryears. In fact, researchers at the US Department of Energy and their consortium,Residential Energy Efficient Distribution Systems (REEDS) have found that ductefficiency may be as low as 50-70%. The US Department of Energy has stated that there ispotential for energy saving in the magnitude of 90 Billion kWh by increasing home energyefficiency.

Other studies have emphasized this. A report published in 2006 by the McKinsey GlobalInstitute, asserted that "there are sufficient economically viable opportunities for energy-productivity improvements that could keep global energy-demand growth at less than 1percent per annum"—less than half of the 2.2 percent average growth anticipated through2020 in a business-as-usual scenario.

Energy productivity, which measures the output and quality of goods and services per unitof energy input, can come from either reducing the amount of energy required to producesomething, or from increasing the quantity or quality of goods and services from the sameamount of energy.

The Vienna Climate Change Talks 2007 Report, under the auspices of the United NationsFramework Convention on Climate Change (UNFCCC), clearly shows "that energyefficiency can achieve real emission reductions at low cost.

Modern appliances, suchas refrigerators, freezers, ovens, stoves, dishwashers, and clotheswashers and dryers, use significantly less energy than olderappliances. Installing a clothesline will significantly reduce yourenergy consumption as your dryer will be used less. Current energyefficient refrigerators, for example, use 40 percent less energy thanconventional models did in 2001. Following this, if all households inEurope changed their more than ten year old appliances into newones, 20 billion kWh of electricity would be saved annually, hencereducing CO2 emissions by almost 18 billion kg. In the US, thecorresponding figures would be 17 billion kWh of electricity and27,000,000,000 lb (1.2×1010 kg) CO2. According to a 2009 studyfrom McKinsey & Company the replacement of old appliances is oneof the most efficient global measures to reduce emissions ofgreenhouse gases. Modern power management systems also reduceenergy usage by idle appliances by turning them off or putting theminto a low-energy mode after a certain time. Many countries identifyenergy-efficient appliances using energy input labeling.

The impact of energy efficiency on peak demand depends on whenthe appliance is used. For example, an air conditioner uses moreenergy during the afternoon when it is hot. Therefore, an energyefficient air conditioner will have a larger impact on peak demandthan off-peak demand. An energy efficient dishwasher, on the otherhand, uses more energy during the late evening when people dotheir dishes. This appliance may have little to no impact on peakdemand.

A building’s location and surroundings play a key rolein regulating its temperature and illumination. Forexample, trees, landscaping, and hills can provideshade and block wind. In cooler climates, designingnorthern hemisphere buildings with south facingwindows and southern hemisphere buildings withnorth facing windows increases the amount of sun(ultimately heat energy) entering the building,minimizing energy use, by maximizing passive solarheating. Tight building design, including energy-efficient windows, well-sealed doors, and additionalthermal insulation of walls, basement slabs, andfoundations can reduce heat loss by 25 to 50 percent.

Dark roofs may become up to 39 C° (70 F°) hotterthan the most reflective white surfaces, and theytransmit some of this additional heat inside thebuilding. US Studies have shown that lightly coloredroofs use 40 percent less energy for cooling thanbuildings with darker roofs. White roof systems savemore energy in sunnier climates. Advanced electronicheating and cooling systems can moderate energyconsumption and improve the comfort of people inthe building.

Proper placement of windows and skylights as well as the useof architectural features that reflect light into a building canreduce the need for artificial lighting. Increased use of naturaland task lighting has been shown by one study to increaseproductivity in schools and offices. Compact fluorescentlights use two-thirds less energy and may last 6 to 10 timeslonger than incandescent light bulbs. Newer fluorescent lightsproduce a natural light, and in most applications they are costeffective, despite their higher initial cost, with paybackperiods as low as a few months.

Effective energy-efficient building design can include the useof low cost Passive Infra Reds (PIRs) to switch-off lightingwhen areas are unnoccupied such as toilets, corridors or evenoffice areas out-of-hours. In addition, lux levels can bemonitored using daylight sensors linked to the building'slighting scheme to switch on/off or dim the lighting to pre-defined levels to take into account the natural light and thusreduce consumption. Building Management Systems (BMS)link all of this together in one centralised computer to controlthe whole building's lighting and power requirements. Thechoice of which space heating or cooling technology to use inbuildings can have a significant impact on energy use andefficiency. For example, replacing an older 50%efficient natural gas furnace with a new 95% efficient one willdramatically reduce energy use, carbon emissions, and winternatural gas bills.

Ground source heat pumps can be even more energyefficient and cost effective. These systems use pumps andcompressors to move refrigerant fluid around athermodynamic cycle in order to "pump" heat against itsnatural flow from hot to cold, for the purpose of transferringheat into a building from the large thermal reservoircontained within the nearby ground. The end result is thatheat pumps typically use four times less electrical energy todeliver an equivalent amount of heat than a direct electricalheater does. Another advantage of a ground source heatpump is that it can be reversed in summertime and operateto cool the air by transferring heat from the building to theground. The disadvantage of ground source heat pumps istheir high initial capital cost, but this is typically recoupedwithin five to ten years as a result of lower energy use.

Smart meters are slowly being adopted by the commercialsector to highlight to staff and for internal monitoringpurposes the building's energy usage in a dynamicpresentable format. The use of Power Quality Analysers canbe introduced into an existing building to assess usage,harmonic distortion, peaks, swells and interruptionsamongst others to ultimately make the building moreenergy-efficient. Often such meters communicate by usingwireless sensor networks.

Green Building XML (GBXML) is an emerging schema, a subset of the BuildingInformation Modeling efforts, focused on green building design and operation. gbXMaL isused as input in several energy simulation engines. But with the development of moderncomputer technology, a large number of building energy simulation tools are available onthe market. When choosing which simulation tool to use in a project, the user mustconsider the tool's accuracy and reliability, considering the building information they haveat hand, which will serve as input for the tool. Yezioro, Dong and Leite developed anartificial intelligence approach towards assessing building performance simulation resultsand found that more detailed simulation tools have the best simulation performance interms of heating and cooling electricity consumption within 3% of mean absolute error.

A deep energy retrofit is a whole-building analysis and construction process that uses toachieve much larger energy savings than conventional energy retrofits. Deep energyretrofits can be applied to both residential and non-residential (“commercial”) buildings.A deep energy retrofit typically results in energy savings of 30 percent or more, perhapsspread over several years, and may significantly improve the building value. The EmpireState Building is undergoing a deep energy retrofit process that is projected to becompleted in 2013. Upon completion, the project team, consisting of representativesfrom Johnson Controls, Rocky Mountain Institute, Clinton Climate Initiative, and JonesLang LaSalle will have achieved an annual energy use reduction of 38% and $4.4million. The Indianapolis City-County Building recently underwent a deep energy retrofitprocess, which has achieved an annual energy reduction of 46% and $750,000 annualenergy savings.

A presentation by-

DIVYANSH KHARE