Packaged Residential Active-Solar Space-Conditioning System. Appendix A. Calmac Ground-Coupled Heat Pump System. Final Subcontract Report

摘要

This report documents Calmac's final design and design development process for a ground-coupled heat pump that provided year-round heating and cooling with no back-up system. Calmac's design uses the ground as a solar collector, large storage mass, and heat sink. Their system consists of a water-to-air reversible heat pump in which energy flows through a closed-loop, ground-coupled heat exchanger. Calmac engineers designed the pump to be more cost-effective when compared to other heat pumps. Their innovations included: (1) surrounding the system's tubing with concrete, which minimizes shrinking of soil and improves heat transfer to the soil, and reduces trenching requirements; (2) developing a low-cost, high-efficiency refrigerant-to-liquid heat exchanger, which functions equally well as an evaporator and a condenser; and (3) using a two-speed compressor, which can meet peak needs as well as standard needs. The system was tested at two locations in Englewood, New Jersey from October 1983 through September 1984, demonstrating yearly coefficients of performance (COPs) of 2.75 (heating) and 2.67 (cooling) at site one and 2.62 (heating) and 2.63 (cooling) at the second site. (ERA citation 11:050364)