This invention relates to a heat-transfer liquid medium for indoor air heat transfer. The heat-transfer liquid medium is composed of liquids A, B and C. Liquid A is composed of isopentane 40-60 wt.% and dichloromethane 40-60 wt.%. Liquid B is composed of diphenyl oxide 7-10 wt.%, biphenyls 12-15 wt.%, anhydrous methanol 34-38 wt.%, anhydrous ethanol 34-38 wt.%, acetone 1-3 wt.% and toluene 3-5 wt.%. Liquid C is solely composed of Triton. The contents of liquids B and C are 0.039 wt.% and 0.0535 wt.% of liquid A, respectively. The heat-transfer liquid medium solves the problems of environmental pollution caused by Freon, and has such advantages as rapid heat transfer, low energy consumption and high safety. |