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Just as horsepower and candlepower were intuitive units of measure for people living through the transition from horse to steam power [3] and from flame-based to electric lighting, so was the ton of refrigeration an intuitive unit of measure during a technological change, as the ice trade gradually included growing percentages of artificial ice ...
Less work is required to move heat than for conversion into heat, and because of this, heat pumps, air conditioners and refrigeration systems can have a coefficient of performance greater than one. The COP is highly dependent on operating conditions, especially absolute temperature and relative temperature between sink and system, and is often ...
horsepower-hour: hph hp⋅h 1.0 hp⋅h (0.75 kWh) British thermal unit: British thermal unit: Btu Btu The International Steam Table British thermal unit is used. For others, see the full list. 1.0 Btu (1.1 kJ) BTU BTU TNT-based units: gigatonne of TNT: GtTNT (none) 1.0 gigatonne of TNT (4.2 EJ) gigaton of TNT: GtonTNT (none) megatonne of TNT ...
The hourly ventilation rate divided by the volume of a space. For perfectly mixed air or laminar flow spaces, this is equal to the number of times per hour that the volume the space is exchanged by mechanical and natural ventilation. Also called air change rate or air exchange rate. Abbreviated ACH or ac/hr. air conditioner
Clean air delivery rate (CADR) is the amount of clean air an air cleaner provides to a room or space. When determining CADR, the amount of airflow in a space is taken into account. For example, an air cleaner with a flow rate of 30 cubic metres (1,000 cu ft) per minute and an efficiency of 50% has a CADR of 15 cubic metres (500 cu ft) per minute.
It is the rate of heat transfer needed to freeze 1 short ton (907 kg) of water into ice in 24 hours. In the United States and Canada, the R-value that describes the performance of thermal insulation is typically quoted in square foot degree Fahrenheit hours per British thermal unit (ft 2 ⋅°F⋅h/Btu). For one square foot of the insulation ...
In the United States, the efficiency of air conditioners is often rated by the seasonal energy efficiency ratio (SEER) which is defined by the Air Conditioning, Heating, and Refrigeration Institute, a trade association, in its 2008 standard AHRI 210/240, Performance Rating of Unitary Air-Conditioning and Air-Source Heat Pump Equipment. [1]
A representative pressure–volume diagram for a refrigeration cycle. Vapour-compression refrigeration or vapor-compression refrigeration system (VCRS), [1] in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for air conditioning of buildings and automobiles.