HEAT MEDIUM CIRCULATION SYSTEM

[Object] The present disclosure provides a heat medium circulation system which safely disperses leaked refrigerant to outside atmosphere and which further enhances safety.[Solving Means] A heat medium circulation system 100 in the present disclosure includes: a refrigerant circuit 110 which is formed by annularly connecting a compressor 111, a use-side heat exchanger 112, an expander 113 and a heat source-side heat exchanger 114 to one another; a heat medium circuit 120 through which heat medium cooled or heated by the use-side heat exchanger 112 by means of refrigerant discharged from the compressor 111 circulates; and a control device 130, in which the heat medium circuit 120 is provided therein at least with a circulation device through which the heat medium circulates, a heating device 127 for electrically heating the heat medium, and a deaerating device 128 which discharges the circulating gas in the heat medium circuit 120 to outside the heat medium circuit 120. The heat medium circulation system 100 uses flammable refrigerant. The heating device 127 is placed downstream of the circulation device and on a side higher than the circulation device, and the deaerating device 128 is placed downstream of the heating device 127 and on a side higher than the heating device 127.