18 May 2017

O.1.4.1 Prototype air-source integrated heat pump field evaluation results

This paper presents results from a field evaluation of a prototype air-source integrated heat pump (AS-IHP) system. The system consists of a high-efficiency, variable-speed (VS) air-source heat pump (ASHP) coupled with a prototype water heating/dehumidification (WH/DH) module. Major operating modes for the AS-IHP system include space cooling (SC), space heating (SH), water heating (WH), and combined SH+WH and SC+WH. In addition the WH/DH module provides dedicated year round dehumidification (DH) and whole house ventilation capability. The AS-IHP design is particularly amenable to home HVAC/WH retrofit applications as well as to new construction. Design of the prototype was completed in spring 2015 and it was installed in an unoccupied single-family research home in June-July 2015. Field monitoring began in August 2015 and continued through September 2016. Analyses described in this paper indicate measured, average, system coefficient of performances (COPs) of 4.7 for cooling, 2.24 for heating, and average monthly WH COPs of ~2.3-2.5 and ~1.9-2.3 in summer and winter, respectively. Total energy savings relative to a minimum efficiency ASHP and electric water heater are estimated at 29% for the 2015-2016 test year. In addition, on-demand DH maintained the indoor space relative humidity (RH) level at =55% throughout the evaluation period. This feature will be critical to ensuring occupant comfort in low-load, high performance homes located in humid climates.