Exergy According to the laws of thermodynamics we know that energy is always conserved, that 'heat' is 'energy' is 'work', and that no system can convert a potential energy in 100% useful work. It is a theoretical maximum amount of work which can never be fully achieved due to the inefficiencies in all systems (both natural and man-made). However, while 100% conversion from energy to work is not possible, the efficiency of the system can be controlled. More efficient systems convert more energy to work and are more desirable. Exergy loss minimisation is one approach that can be implemented to manage and improve a system's efficiency. 2 Laws of Thermodynamics Energy is always conserved during transformation from one form to another. energy can neither be created nor destroyed during a conversion process, what goes in must come out. Nor in fact can anyone 'create' energy - it can merely be converted from one form to another. No system can convert 100% of the energy input into work in converting energy from one form to another there will always be some loss. No system is perfectly efficient, and the often the greatest source of loss is heat (which is energy).
Efficiency is a measure of how well a device transfers energy into the form we want. efficiency (%) = (useful energy out ÷ total energy in) x 100. or efficiency (%) = (useful power out ÷ total power in) x 100. Efficiency www.wolfatthedoor.org.uk
Kinetic Energy Recovery System (KERS) KERS recovers the kinetic energy that is present in the waste heat created by the car’s braking process. It stores that energy and converts it into power that can be called upon to boost acceleration. Unlike production vehicle hybrids that convert kinetic energy to electrical energy and store it in a battery, the KERS is far more compact and lighter, adding only about 55lbs to the car. The amount of energy that can be stored is limited but for this type of application it is actually useful since the cars are constantly accelerating and decelerating from corner to corner. Source: http://www.gizmag.com/go/7396/
Wasted Energy By HANNAH FAIRFIELD- New York TimesIt's gone before you even knew it was there: As energy is unlocked from fuels at power plants, two-thirds of the energy consumed to create electricity is lost.The laws of thermodynamics dictate that conversion efficiency will never be 100 percent, because heat is lost at every step of the conversion process. But new technologies may be able to greatly increase conversion efficiency, moving from an overall rate of 36 percent to closer to 50 percent.At present, coal — in all its carbon-belching inefficiency — is king because it's cheap. Still, the use of natural gas to create electricity has been rising rapidly, in part because of more-efficient gas turbines."High fossil fuel prices will drive technology and innovation, because they respond to price signals," said Frank A. Wolak, an economist at Stanford. "Technology can improve efficiency by working the margin, gaining 10 to 15 percent. That's money."Adding a carbon tax or regulating carbon trading could also change price incentives, increasing demand for nuclear and renewable energy sources."Once the cost of burning fossil fuels doubles, the renewable energy options begin to look really good," said Jon G. McGowan, a mechanical engineer at the University of Massachusetts. http://www.nytimes.com
Greenhouse gas emissions The primary greenhouse gases in the Earth's atmosphere are water vapour, carbon dioxide, methane, nitrous oxide, and ozone. Greenhouse gas emissions By Countries http://www.carbonplanet.com/country_emissions
Low Energy Building A Low-energy house is any type of house that from design, technologies, and building products and uses less energy, from any source, than a traditional or average contemporary house. The term could also refer to any dwelling whose energy use is below the standards demanded by current building codes. Because national standards vary considerably around the world, 'low energy' developments in one country may not meet 'normal practice' ones in another. Net Zero Energy Building Energy Autarkic House: A building concept where the balance of the own energy consumption and production can be made on an hourly or even smaller basis. - Able to produce enough/more energy than required at any given time. A zero energy building (ZEB) or net zero energy building is a general term applied to a building's use with zero net energy consumption and zero carbon emissions annually. Plus Energy Building An energy-plus-house produces more energy from renewable energy sources, on average over the course of a year, than it imports from external sources.
Net Zero Energy Building Definitions Summary P. Torcellini, S. Pless, and M. Deru National Renewable Energy Laboratory