Daikin Industries, Ltd.

Takenori Mezaki

Akitoshi Ueno

Satoru Sakae

Isao Kondo

Takahito Nakayama

Yuji Fujimoto

Yasutoshi Mizutani

Yoshihiro Nishioka

Provided is a refrigeration apparatus with improved safety. A refrigeration apparatus includes: a compressor; a heat source-side expansion valve to be controlled to have a minimum opening degree and brought into a closed state in which the heat source-side expansion valve maximizes prevention of a flow of a refrigerant toward a usage-side refrigerant circuit; a fusible plug; a controller; and a refrigerant leak detector configured to detect a refrigerant leak at the usage-side refrigerant circuit. The fusible plug is disposed in a refrigerant circuit, and is brought into an open state to allow the refrigerant circuit to communicate with an external space. When the refrigerant leak detector detects a refrigerant leak at the usage-side refrigerant circuit, the controller performs refrigerant leak first control to bring the heat source-side expansion valve into the closed state, and performs refrigerant leak second control to bring the fusible plug into the open state.

Refrigeration apparatus with leak detection on the usage side and a refrigerant release mechanism

Provided is a refrigeration apparatus that secures safety while suppressing an increase in cost. A refrigeration apparatus performs a refrigeration cycle in a refrigerant circuit including a compressor, a heat source-side heat exchanger, and a usage-side heat exchanger. The refrigeration apparatus comprises a usage-side fan providing an air flow, and a controller. The usage-side fan is disposed in a target space where inside air is cooled. The controller performs a refrigerant leak determination process to determine whether a refrigerant leak occurs, based on a state of a refrigerant in the refrigerant circuit. When the controller performs the refrigerant leak determination process to determine that a refrigerant leak occurs, then the controller performs leakage refrigerant agitation control to operate the usage-side fan so as to suppress local emergence of a region where the refrigerant leaks at a high concentration in the target space.

Refrigeration apparatus

It includes a heat source side refrigerant circuit ( ) having a plurality of refrigerant heat exchangers ( ), and a plurality of user-side refrigerant circuits ( ). A high pressure gas pipe (LG-H) is connected to the discharge side of outdoor compressors ( ) of the heat source side refrigerant circuit ( ), a low pressure gas pipe (LG-L) to the suction side of the outdoor compressors ( ), and a liquid pipe (LL) to the liquid side of outdoor heat source side heat exchangers ( ). The liquid pipe (LL) is connected to one end side of each refrigerant heat exchanger ( ). The other end side of the respective refrigerant heat exchangers ( ) can be switched by three-way valves ( ) between a state where it is communicated to the high pressure gas pipe (LG-H) and another state where it is communicated to the low pressure gas pipe (LG-L). The liquid pipe (LL) is connected to one end side of a user-side heat exchanger ( ) of the heat source side refrigerant circuit ( ). The other end side of the user-side heat exchanger ( ) can be switched by a three-way valve ( ) between a state where it is communicated to the high pressure gas pipe (LG-H) and another state where it is communicated to the low pressure gas pipe (LG-L).

Refrigeration system

A first refrigeration circuit for a refrigerating apparatus which is formed into a two-stage cascade refrigerating cycle by establishing connection between a high temperature-side refrigerant circuit and a low temperature-side refrigerant circuit through a refrigerant heat exchanger, and a second refrigeration circuit which is formed into a refrigerating cycle different from that of the first refrigeration circuit are provided. A liquid piping line of the high temperature-side refrigerant circuit and a liquid piping line of the second refrigeration circuit are connected together through a first connection piping line and a suction-side gas piping line of the high temperature-side refrigerant circuit and a suction-side gal line of the second refrigeration circuit are connected together through a second connection piping line. Switching members are disposed for selective circulation of a refrigerant of the second refrigeration circuit to the refrigerant heat exchanger of the first refrigeration circuit through each of the connection piping lines, whereby, even when a heat source equipment stops operating in a two-stage cascade refrigerating cycle refrigeration system applied to a showcase or the like, it becomes possible to achieve continuation of refrigeration operation.

Refrigerating device

A first refrigeration circuit (,) for a refrigerating apparatus (,) which is formed into a two-stage cascade refrigerating cycle by establishing connection between a high temperature-side refrigerant circuit (,) and a low temperature-side refrigerant circuit (,) through a first refrigerant heat exchanger (,A), a second refrigeration circuit (,) which is formed into a refrigerating cycle different from that of the first refrigeration circuit (,), and a second refrigerant heat exchanger (,B) connected to the low temperature-side refrigerant circuit (,) are provided. The second refrigerant heat exchanger (,B) is connected, through connection piping lines (,), to a liquid piping line (,) and a suction-side gas piping line (,) of the second refrigeration circuit (,). First switching means (,) are disposed for selective circulation of a refrigerant of the second refrigeration circuit (,) to the second refrigerant heat exchanger (,B) through the connection piping lines (,), whereby, even when a heat source equipment (,) stops operating in a two-stage cascade refrigerating-cycle refrigeration system applied to a showcase or the like, it becomes possible to achieve continuation of refrigeration operation.

An outdoor unit (,), a parent unit (,), a plurality of child freezers, and a plurality of child refrigerators are provided. The child freezers are disposed in individual frozen display cases, while the child refrigerators are disposed in individual refrigerated display cases. A refrigerant heat exchanger (,) is disposed in only the parent unit (,). The outdoor unit (,) and the refrigerant heat exchanger (,) form a primary refrigerant circuit. A secondary refrigerant circuit is provided in the parent unit (,). Refrigerant circulates through the secondary refrigerant circuit, passing through the refrigerant heat exchanger (,). Each child freezer is provided with a refrigeration utilization side heat exchanger (,) and the heat exchanger (,) and the refrigerant heat exchanger (,) form a secondary refrigerant circuit through which refrigerant circulates. Together with the outdoor unit (,), a heat exchanger which is disposed in each of the child refrigerators forms a secondary refrigerant circuit of a unary refrigeration cycle.

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Osaka, Japan

Takenori Mezaki