A study of the characteristics of closed, water-loop heat pump systems has been conducted. The study included an analysis of the existing and potential market for this approach to the space conditioning of medium and large commercial structures. Opportunities for optimising overall system performance relative to loop water operating temperatures, loop water flow rates, and additional thermal storage were investigated. Comparisons were also developed relative to alternative space-conditioning systems on both an operating cost basis and an installed cost. Additional topics include the impacts of ground coupling and domestic water heating on system performance. The significant findings of the study are included.

KEYWORDS: heat pumps, water heat pumps, calculating, air conditioning, commercial, buildings, performance, energy storage, comparing, operations, costs, installing, ground water, domestic, water heating.