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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.
If the mean daily temperature is above 65 °F, the mean degrees Fahrenheit above 65 °F are counted as the cooling degree day. The heating and cooling degree days are tallied separately to calculate monthly, seasonal, and yearly total heating and cooling degree days. Heating and cooling degree days closely correlate with heating and cooling demand.
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.
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.
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:
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.
Hot summer days in the United States have only been getting hotter. In the 25 largest US cities, days with highs breaking the 100-degree Fahrenheit barrier have become more common over the past 75 ...
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.