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United States Heating Degree Day map, 1961–1990 United States Cooling Degree Day map, 1961–1990. Heating degree day (HDD) is a measurement designed to quantify the demand for energy needed to heat a building. HDD is derived from measurements of outside air temperature.
Degree days are a useful metric for estimating energy consumption required for household heating and cooling, and in this context are formally referred to as heating degree days. Since the escape or ingress of heat due to conduction is proportional to the difference between the indoor and outdoor temperature, the amount of energy needed to ...
The building balance point temperature is the outdoor air temperature when the heat gains of the building are equal to the heat losses. [1] Internal heat sources due to electric lighting, mechanical equipment, body heat, and solar radiation may offset the need for additional heating although the outdoor temperature may be below the thermostat set-point temperature.
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.
It is commonly applied to the calculation of heat transfer in heat exchangers, but can be applied equally well to other problems. For the case of a heat exchanger, U {\displaystyle U} can be used to determine the total heat transfer between the two streams in the heat exchanger by the following relationship:
Sol-air temperature (T sol-air) is a variable used to calculate cooling load of a building and determine the total heat gain through exterior surfaces. It is an improvement over: It is an improvement over:
Classical pinch-analysis primarily calculates the energy costs for the heating and cooling utility. At the pinch point, where the hot and cold streams are the most constrained, large heat exchangers are required to transfer heat between the hot and cold streams. Large heat exchangers entail high investment costs.