Open AccessHow to heat and cool a home with 400 CFM supply air and keep the ducts in the conditioned space
Author(s) -
J.W. Andrews
Publication year - 1999
Language(s) - English
Resource type - Reports
DOI - 10.2172/354896
Subject(s) - duct (anatomy) , air conditioning , air space , constant air volume , envelope (radar) , room air distribution , building envelope , ventilation (architecture) , environmental science , cooling load , natural ventilation , fan coil unit , engineering , air change , mechanical engineering , meteorology , thermal , physics , aerospace engineering , medicine , radar , pathology
A design strategy is presented that can enable a typical new home to be heated, cooled, and ventilated with less than 400 cfm of delivered air. The strategy has three major elements. First, peak cooling loads are minimized by using good available technologies for the envelope, with emphasis on minimizing heat gains through the windows. Second, the envelope is designed to have very low natural air leakage rates, such that all the ventilation air can be drawn in at one point and passed over the cooling coil before it is mixed with the house air. This permits a significant portion of the cooling load to be met at an air flow rate of {approximately} 200 cubic feet per minute (cfm) per ton, compared with the typical 400 cfm per ton in standard air-conditioning systems. Third, by reducing the amount of supply air needed to meet the envelope loads, the required size of ductwork is reduced, making it easier to locate the ducts within the conditioned space. This reduces duct loads to zero, completing the three-part energy conserving strategy