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The first of the cooling load factors used in this method is the CLTD, or the Cooling Load Temperature Difference. This factor is used to represent the temperature difference between indoor and outdoor air with the inclusion of the heating effects of solar radiation. [1] [5] The second factor is the CLF, or the cooling load factor.
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.
When the two temperature differences are equal, this formula does not directly resolve, so the LMTD is conventionally taken to equal its limit value, which is in this case trivially equal to the two differences. With this definition, the LMTD can be used to find the exchanged heat in a heat exchanger:
A liquid (glycol based) chiller with an air cooled condenser on the rooftop of a medium size commercial building. In air conditioning systems, chilled coolant, usually chilled water mixed with ethylene glycol, from a chiller in an air conditioning or cooling plant is typically distributed to heat exchangers, or coils, in air handlers or other types of terminal devices which cool the air in ...
In the United Kingdom, a Seasonal Energy Efficiency ratio (SEER) for refrigeration and air conditioning products, similar to the ESEER but with different load profile weighting factors, is used for part of the Building Regulations Part L calculations within the Simplified Building Energy Model (SBEM) software, and are used in the production of Energy Performance Certificates (EPC) for new ...
The SEER rating of a unit is the cooling output during a typical cooling-season divided by the total electric energy input during the same period. The higher the unit's SEER rating the more energy efficient it is. In the U.S., the SEER is the ratio of cooling in British thermal units (BTUs) to the energy consumed in watt-hours.
An example two-stage process is shown at right. (Bottom on mobile) The cascade cycle is often employed for devices such as ULT freezers. [1] In a cascade refrigeration system, two or more vapor-compression cycles with different refrigerants are used.
The law holds well for forced air and pumped liquid cooling, where the fluid velocity does not rise with increasing temperature difference. Newton's law is most closely obeyed in purely conduction-type cooling. However, the heat transfer coefficient is a function of the temperature difference in natural convective (buoyancy driven) heat transfer.