Temperature adjustment system

Abstract

A temperature adjustment system includes a first unit. The first unit includes a refrigerant circuit through which a highly flammable refrigerant circulates, a second water pipe, and a first heat exchanger. The second water pipe is a heat source-side water pipe connected to the first water pipe. The first heat exchanger exchanges heat between the water and the refrigerant. The first unit further includes an automatic on-off valve that automatically releases the water in the first heat exchanger at a low temperature.

1 . A temperature adjustment system configured to send temperature-adjusted water to a first water pipe that is a utilization-side water pipe, the temperature adjustment system comprising a first unit, the first unit including:
 a refrigerant circuit through which a refrigerant that is highly flammable is circulatable;   a second water pipe that is a heat source-side water pipe connected to the first water pipe;   a first heat exchanger configured to exchange heat between the water and the refrigerant; and   an automatic on-off valve that is configured to automatically release water from the first heat exchanger at a temperature below a threshold temperature.   
     
     
         2 . The temperature adjustment system according to  claim 1 , wherein the automatic on-off valve:
 is configured to automatically open as a temperature of water flowing through the first heat exchanger falls below a first threshold value, and   is configured to automatically close as the temperature of water flowing through the first heat exchanger exceeds a second threshold value higher than the first threshold value.   
     
     
         3 . The temperature adjustment system according to  claim 1 , wherein the automatic on-off valve is a mechanical on-off valve whose opening degree is configured to change in accordance with a temperature of water flowing through the first heat exchanger. 
     
     
         4 . The temperature adjustment system according to  claim 2 , wherein the automatic on-off valve is a mechanical on-off valve whose opening degree is configured to change in accordance with a temperature of water flowing through the first heat exchanger. 
     
     
         5 . The temperature adjustment system according to  claim 1 , wherein the first unit further includes a casing that accommodates the refrigerant circuit, the second water pipe, the first heat exchanger, and the automatic on-off valve. 
     
     
         6 . The temperature adjustment system according to  claim 2 , wherein the first unit further includes a casing that accommodates the refrigerant circuit, the second water pipe, the first heat exchanger, and the automatic on-off valve. 
     
     
         7 . The temperature adjustment system according to  claim 3 , wherein the first unit further includes a casing that accommodates the refrigerant circuit, the second water pipe, the first heat exchanger, and the automatic on-off valve. 
     
     
         8 . The temperature adjustment system according to  claim 1 , further comprising a control computer that is configured to control a reverse cycle defrost operation of melting frost adhering to the second heat exchanger,
 wherein:   the first unit further includes a second heat exchanger that is configured to exchange heat between the refrigerant and outdoor air, and   the control computer is configured to stop the reverse cycle defrost operation as the temperature of water flowing through the first heat exchanger falls below a third threshold value during the reverse cycle defrost operation.   
     
     
         9 . The temperature adjustment system according to  claim 2 , further comprising a control computer that is configured to control a reverse cycle defrost operation of melting frost adhering to the second heat exchanger,
 wherein:   the first unit further includes a second heat exchanger that is configured to exchange heat between the refrigerant and outdoor air, and   the control computer is configured to stop the reverse cycle defrost operation as the temperature of water flowing through the first heat exchanger falls below a third threshold value during the reverse cycle defrost operation.   
     
     
         10 . The temperature adjustment system according to  claim 3 , further comprising a control computer that is configured to control a reverse cycle defrost operation of melting frost adhering to the second heat exchanger,
 wherein:   the first unit further includes a second heat exchanger that is configured to exchange heat between the refrigerant and outdoor air, and   the control computer is configured to stop the reverse cycle defrost operation as the temperature of water flowing through the first heat exchanger falls below a third threshold value during the reverse cycle defrost operation.   
     
     
         11 . The temperature adjustment system according to  claim 5 , further comprising a control computer that is configured to control a reverse cycle defrost operation of melting frost adhering to the second heat exchanger,
 wherein:   the first unit further includes a second heat exchanger that is configured to exchange heat between the refrigerant and outdoor air, and   the control computer is configured to stop the reverse cycle defrost operation as the temperature of water flowing through the first heat exchanger falls below a third threshold value during the reverse cycle defrost operation.   
     
     
         12 . The temperature adjustment system according to  claim 5 , wherein:
 the casing has a bottom plate,   the bottom plate has an opening in communication with an outside of the casing, and   the water in the first heat exchanger released from the automatic on-off valve drains to the outside of the casing through the opening.   
     
     
         13 . The temperature adjustment system according to  claim 12 , wherein:
 the first unit further includes a second heat exchanger that is configured to exchange heat between the refrigerant and outdoor air, and   drain water from the second heat exchanger drains from the opening to the outside of the casing.   
     
     
         14 . A temperature adjustment system configured to send temperature-adjusted water to a first water pipe that is a utilization-side water pipe, the temperature adjustment system comprising:
 a refrigerant circuit through which a refrigerant that is highly flammable is circulatable;   a second water pipe that is a heat source-side water pipe connected to the first water pipe;   a first heat exchanger configured to exchange heat between the water and the refrigerant; and   an automatic on-off valve that is configured to automatically release water from the first heat exchanger at a temperature below a threshold temperature.   
     
     
         15 . The temperature adjustment system according to  claim 14 , wherein the automatic on-off valve:
 is configured to automatically open as a temperature of water flowing through the first heat exchanger falls below a first threshold value, and   is configured to automatically close as the temperature of water flowing through the first heat exchanger exceeds a second threshold value higher than the first threshold value.   
     
     
         16 . The temperature adjustment system according to  claim 14 , wherein the automatic on-off valve is a mechanical on-off valve whose opening degree is configured to change in accordance with a temperature of water flowing through the first heat exchanger. 
     
     
         17 . The temperature adjustment system according to  claim 14 , further comprising a casing that accommodates the refrigerant circuit, the second water pipe, the first heat exchanger, and the automatic on-off valve. 
     
     
         18 . The temperature adjustment system according to  claim 17 , wherein:
 the casing has a bottom plate,   the bottom plate has an opening in communication with an outside of the casing, and   the water in the first heat exchanger released from the automatic on-off valve drains to the outside of the casing through the opening.   
     
     
         19 . The temperature adjustment system according to  claim 14 , further comprising:
 a control computer that is configured to control a reverse cycle defrost operation of melting frost adhering to the second heat exchanger; and   a second heat exchanger that is configured to exchange heat between the refrigerant and outdoor air,   wherein the control computer is configured to stop the reverse cycle defrost operation as the temperature of water flowing through the first heat exchanger falls below a third threshold value during the reverse cycle defrost operation.   
     
     
         20 . A heat pump air conditioner comprising the temperature adjustment system according to  claim 14 .