The Effect Of Residential Equipment Capacity On Energy Use, Demand, And Run-Time
Sonne, Jeffrey; Vieira, Robin; Klongerbo, Jon
Installed central air conditioning system capacities in 368 recently-built Florida homes were compared with Manual J load values calculated from house audit data. Over 50% of the homes had installed systems with a cooling capacity greater than 120% of the calculated Manual J value. Thirty-one percent of the 78 heat pump homes in this study had installed heating capacity greater than 120% of the calculated Manual J value. Using submetered data from the air conditioning system, a definite increase in peak energy use was observed for systems sized over 120% of Manual J calculations. The effect of system sizing on the system run-time fractions of units is shown. The homes that had units sized smaller than the calculated Manual J value tended to have higher percentages of maximum hourly run-time fractions. There was little difference in binned percentages of large runtime fractions between homes with installed-to-calculated ratios of 1.0 to 1.2 and those with installed-to-calculated ratios greater than 1.2.
Florida Solar Energy Center and Cummings, Jo Ellen, "The Effect Of Residential Equipment Capacity On Energy Use, Demand, And Run-Time" (1997). FSEC Energy Research Center®. 747.