A comparative study of ground source heat pump and conventional natural gas furnace systems

The results are reported of a thermodynamic, environmental and economic study of two heating and cooling systems for a house in Ontario, Canada. By replacing the natural gas furnace (NGF) and air conditioner (AC) with a new ground source heat pump (GSHP), annual CO₂ emissions decrease by 70%. The GSHP has lower operating and higher initial costs, with a payback period of 11.5 years. The exergy efficiency for the GSHP (70%) is significantly greater than for the NGF (8%). The sustainability indexes are observed to be 3.333 and 1.087 for GSHP and NGF, respectively, implying the GSHP uses resources more efficiently. (author)