Assesses the risks of using six different fluids (methanol, ethanol, aqueous potassium acetate, propylene glycol, aqueous calcium magnesium acetate and aqueous urea) as antifreezes in ground-source heat pump systems. Areas assessed include fire hazard, corrosion and leakage, health hazard, environmental, detailed heat pump system analysis, resulting in predictions of annual energy use, life cycle cost and power plant emissions plus regulatory risk to future use. Propylene glycol had low risk in all areas, potassium acetate, calcium magnesium acetate and urea had low to medium risk in all areas except leakage, which was high for all three, and corrosion, which was high for urea. Ethanol and methanol had high fire risk in their pure forms (but low risk in diluted form) and corrosion problems with iron compounds. In addition, methanol had high environmental and health risks.

Units: SI

KEYWORDS: year 1997, Heat pumps, soil heat pumps, antifreeze, hazards, fire, corrosion, health, environment, energy consumption, costs, fluids, risk assessment