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For example, a typical combined cycle power plant burning methane may have an energy efficiency of 55%, while its exergy efficiency will be 57%. A 100% exergy efficient methane fired power station would correspond to an energy efficiency of 98%. This means that for many of the fuels we use, the maximum efficiency that can be achieved is >90% ...
An energy efficiency or first law efficiency will determine the most efficient process based on wasting as little energy as possible relative to energy inputs. An exergy efficiency or second-law efficiency will determine the most efficient process based on wasting and destroying as little available work as possible from a given input of ...
Energy performance certificates (EPCs) are a rating scheme to summarise the energy efficiency of buildings. [4] [5] The building is given a rating between A (Very efficient) - G (Inefficient). The EPC will also include tips about the most cost-effective ways to improve the home energy rating. Energy performance certificates are used in many ...
A new energy label, introduced in 2010, is based on the energy efficiency index (EEI), and has energy classes in the range A+++ to D. [11] The EEI is a measure of the annual electricity consumption, and includes energy consumed during power-off and standby modes, and the energy consumed in 220 washing cycles. For the washing cycles, a weighted ...
Energy quality is a measure of the ease with which a form of energy can be converted to useful work or to another form of energy: i.e. its content of thermodynamic free energy. A high quality form of energy has a high content of thermodynamic free energy, and therefore a high proportion of it can be converted to work; whereas with low quality ...
The House Energy Rating (HER) or House Energy Rating Scheme (HERS) are worldwide standard measures of comparison by which one can evaluate the energy efficiency of a new or an existing building. The comparison is generally done for energy requirements for heating and cooling of indoor space. The energy is the main criterion considered by any ...
MEPS and energy rating labels help improve the energy efficiency of our [who?] products, and enable consumers to choose products that use less energy. Products covered by MEPS must meet or exceed set levels for energy performance before they can be sold to consumers. MEPS have been updated over the years (2002, 2003, 2004, 2008, 2011) to cover ...
A premium efficiency electric motor: more than 90% (see Main Article: Premium efficiency). A large power transformer used in the electrical grid may have efficiency of more than 99%. Early 19th century transformers were much less efficient, wasting up to a third of the energy passing through them. [citation needed]