Full Title: Feasibility of Foundation Heat Exchangers for Residential Ground Source Heat Pump Systems in the United States
Author(s): James R. Cullin, Lu Xing, Edwin Lee, Jeffrey D. Spitler and Daniel E. Fisher
Publisher(s): Building and Environmental Thermal Systems Research Group at Oklahoma State University
Publication Date: 1/2012



Foundation heat exchangers (FHXs) used in residential  ground source heat pump systems represent a potential cost  savings due to their lesser first cost over other types of heat  exchangers. By simulating a foundation heat exchanger system  for two low-energy house constructions in seventeen United  States locations, a preliminary map detailing the feasibility of  FHX systems in the United States has been developed, with  most of the country showing at least marginal feasibility for the  technology. The FHX simulation process uses decoupled  models of house and basement; the coupling between the two  zones creates a difference of around 1.0°C (1.8°F) in the simulated maximum or minimum heat pump entering fluid temperature. Additionally, the operation of an FHX in the soil around  a house was found to have a negligible impact on soil freezing  near the house foundation. The FHX simulation needs a fully  coupled house/basement model, as well as the capacity to  handle snow cover, to be even more robust.