Conventional air conditioning systems in houses respond to thermal loads by means of controlling dry-bulb temperature through the thermostat. As part of the process of conditioning the air, dehumidification is also provided. However, as houses are becoming more efficient, supplemental dehumidification is often necessary in homes located in hot and humid climates to control relative humidity intentionally. This study compared the dehumidification performance of three residential air conditioning systems: a system with a variable speed mode (VSPD), a system with an enhanced dehumidification mode activated (Enhanced Dehum), and a system without enhanced dehumidification capabilities (Normal Cooling). The research facility was equipped with a Data Acquisition (DAQ) system to record the indoor and outdoor conditions at 15-second intervals. Two types of days were of interest in the study, hot and humid days (summer season) and mild and humid days (shoulder seasons). The dehumidification performance was assessed, and the VSPD mode was able to maintain relative humidity between 50% to 52% on summer days and between 55% to 58% in the fall shoulder season. Enhanced Dehum controlled the relative humidity between 53% to 55% and between 50 to 55% respectively in the summer and fall shoulder seasons. Normal Cooling maintained the relative humidity above 55% in both types of days with levels above 60% in some instances in the fall shoulder season. In terms of efficiency, the VSPD removed more water condensate per kilowatt-hour than Enhanced Dehum and Normal Cooling respectively.

Date of publication

Spring 5-2-2020

Document Type




Persistent identifier


Committee members

Nelson Fumo, Mohammad Abu Rafe Biswas, Shih-Feng Chou


Master of Science in Mechanical Engineering