22 May 2008

OPTIMIZATION OF HYBRID GEOTHERMAL HEAT PUMP SYSTEMS


Hybrid ground-coupled heat pump systems (HyGCHPs) couple conventional groundcoupled
heat pump (GCHP) equipment with supplemental heat rejection or extraction systems.
In unbalanced climates, the use of a supplemental heat rejection/generation device has been shown to significantly improve the economics of the system. However, the design and operation of HyGCHPs are more complex than GCHPs, and there is relatively little information available in this regard that is accessible to the practicing engineer. This paper describes the development of a simulation tool that integrates physics-based models of the HyGCHP
components using the TRNSYS simulation program. The simulation model was used to complete a parametric study of optimal HyGCHP designs over a range of scenarios varying in climate, building type, and economic and physical assumptions. The results of the parametric
study suggest a set of general design guidelines that can be used to select an equipment configuration, size equipment, and control the equipment for a typical HyGCHP system.