DE-2554 -- The Degradation Coefficient of a Field-Tested Self-Contained 3-Ton Air Conditioner PDF

The previous ratings of A/C units required by ARI used only steady state testing at one set of conditions; 35°C (95°F) outdoor temperature and 27°C - 19°C (80°F - 67°F) indoor dry bulb and wet bulb, respectively. This ARI point defined the conditions for nameplate cooling capacities of all small residential units. In order to evaluate an average capacity or efficiency of an installed unit, the unit's performance must be known at conditions other than the ARI point. Since units are installed which have more capacity than the cooling load usually requires, the cyclic behavior of the A/C must also be known. The seasonal performance then takes into account the cycling behavior over a wide range of temperatures, such as would be encountered during a summer period.