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Pentafluoroethane is a common replacement for various chlorofluorocarbons (i.e Freon) in new refrigerant systems, especially for air-conditioning. The zeotropic mix of difluoromethane with pentafluoroethane ( R-125 ) and tetrafluoroethane ( R-134a ) is known as R-407A through R-407F depending on the composition.
Air changes per hour, abbreviated ACPH or ACH, or air change rate is the number of times that the total air volume in a room or space is completely removed and replaced in an hour. If the air in the space is either uniform or perfectly mixed, air changes per hour is a measure of how many times the air within a defined space is replaced each hour.
R-12 was used in most refrigeration and vehicle air conditioning applications prior to 1994 before being replaced by 1,1,1,2-tetrafluoroethane (R-134a), which has an insignificant ozone depletion potential. Automobile manufacturers began phasing in R-134a around 1993 [citation needed].
= air pollutant concentration, in parts per million by volume mg/m 3 = milligrams of pollutant per cubic meter of air = atmospheric temperature in kelvins = 273.15 + °C 0.08205 = Universal Gas Law constant in atm·l/(mol·K) = molecular weight of the air pollutant (dimensionless)
The coefficient of performance or COP (sometimes CP or CoP) of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work (energy) required. [1] [2] Higher COPs equate to higher efficiency, lower energy (power) consumption and thus lower operating costs. The COP is used in thermodynamics.
Dichlorodifluoromethane (R-12 or CFC-12), the most commonly used Freon brand refrigerant prior to its ban in many countries in 1996 and total ban in 2010. 1,1,1,2-Tetrafluoroethane (R-134a or HFC-134a), one of the main replacements for the formerly widespread R-12. Opteon halogenated olefins now replacing Freons in many applications.
Cooling capacity is the measure of a cooling system's ability to remove heat. [1] It is equivalent to the heat supplied to the evaporator/boiler part of the refrigeration cycle and may be called the "rate of refrigeration" or "refrigeration capacity".
Observed concentrations have been in the range of 0.1–4.8 parts per billion in rural air, 4–10.5 ppb in urban air, and 7–260 ppb in industrial air samples. [ 9 ] In the United States and some European countries a threshold limit value of 500 parts per million ( ppm ) was established for occupational (8-hour time-weighted average ) exposure.