SPLIT-SYSTEM RESIDENTIAL HEAT PUMP WITH SEPARATE DEHUMIDIFICATION OPERATING MODE
Residential air conditioners and heat pumps operate when the room thermostat senses a temperature above the control set point temperature. Systems are designed to provide dehumidification simultaneously with cooling operation and split-system components can be selected to bias performance toward greater dehumidification. Even so, there are times when the incidental moisture removal capacity of the system is not sufficient to keep indoor humidity within desired limits. This situation is common during the spring and autumn, when the sensible cooling load is low and, in humid climates, can occur throughout the cooling season. This paper reviews the background and development of a split-type heat pump system with three operating modes: heating, cooling, and dehumidifying. An analytical method was developed to assess the effectiveness and operating cost of active dehumidification options. Several technologies were compared and contrasted using this evaluation tool. A split-system heat pump that flexibly controls both indoor temperature and humidity was built and tested. Laboratory and field performance results are presented.