Refrigeration apparatus

Abstract

A refrigeration apparatus includes: a first refrigerant circuit including a first heat exchanger configured to release heat from carbon dioxide serving as a first refrigerant; a second refrigerant circuit including a second heat exchanger configured to release heat from a second refrigerant having combustibility or toxicity or a second refrigerant having a global warming potential equal to four or more, and a decompressor configured to decompress the second refrigerant; and a third heat exchanger configured to cause heat exchange between the first refrigerant having radiated heat in the first heat exchanger and the second refrigerant having radiated heat in the second heat exchanger and then decompressed in the decompressor; in which the second heat exchanger includes a plurality of flat multi-hole tubes.

What is claimed is: 
     
         1 . A refrigeration apparatus comprising:
 a first refrigerant circuit including a first heat exchanger configured to release heat from carbon dioxide serving as a first refrigerant;   a second refrigerant circuit including a second heat exchanger configured to release heat from a second refrigerant having combustibility or toxicity or a second refrigerant having a global warming potential equal to four or more, and a decompressor configured to decompress the second refrigerant; and   a third heat exchanger configured to cause heat exchange between the first refrigerant having radiated heat in the first heat exchanger and the second refrigerant having radiated heat in the second heat exchanger and then decompressed in the decompressor; wherein   the second heat exchanger includes a plurality of flat multi-hole tubes.   
     
     
         2 . The refrigeration apparatus according to  claim 1 , further comprising
 a control device configured to control operation of the first refrigerant circuit and the second refrigerant circuit, and a fan configured to generate an air flow to be supplied to the first heat exchanger and the second heat exchanger, wherein   the first heat exchanger and the second heat exchanger are aligned in a direction of the air flow generated by the fan, and   the control device executes a first mode of operating both the first refrigerant circuit and the second refrigerant circuit to cause the first heat exchanger to release heat from the first refrigerant and cause the second heat exchanger to release heat from the second refrigerant, and a second mode of solely operating the first refrigerant circuit to cause the first heat exchanger to evaporate the first refrigerant.   
     
     
         3 . The refrigeration apparatus according to  claim 1 , wherein
 the second heat exchanger includes the plurality of flat multi-hole tubes, and a fin meanderingly disposed between the flat multi-hole tubes adjacent to each other.   
     
     
         4 . The refrigeration apparatus according to  claim 1 , wherein the second refrigerant circuit uses the second refrigerant in a quantity of 1000 g or less. 
     
     
         5 . The refrigeration apparatus according to  claim 4 , wherein the second refrigerant circuit uses the second refrigerant in a quantity of 150 g or less.