Cooling system

A method comprising:

• removing, by a high side heat exchanger, heat from a refrigerant;
• storing, by a flash tank, the refrigerant from the high side heat exchanger;
• receiving, by a subcooler heat exchanger, the refrigerant from the flash tank;
• during a first mode of operation:
• directing, by the subcooler heat exchanger, refrigerant from the flash tank to an input of a first load;
• using, by the first load, the refrigerant from the subcooler heat exchanger to cool a first space proximate the first load;
• and
• compressing, by a first compressor, the refrigerant from the first load;
• during a second mode of operation:
• directing, by the subcooler heat exchanger, the refrigerant from the flash tank to an input of an expansion valve;
• generating, by the subcooler heat exchanger, a heated refrigerant by transferring heat from the refrigerant from the flash tank to the refrigerant from the expansion valve;
• directing, by the subcooler heat exchanger, a first portion of the heated refrigerant to the input of the first load;
• directing, by the subcooler heat exchanger, a second portion of the heated refrigerant to the first compressor;
• compressing, by the first compressor, the heated refrigerant from the subcooler heat exchanger;
• and
• directing, by the first compressor, the compressed refrigerant from the subcooler heat exchanger to the first load to defrost the first load.

A system comprising:

• a high side heat exchanger configured to remove heat from a refrigerant;
• a flash tank configured to store the refrigerant from the high side heat exchanger;
• an expansion valve;
• a first load;
• a second load;
• a first compressor;
• a second compressor;
• and
• a subcooler heat exchanger configured to receive the refrigerant from the flash tank, wherein:
• the subcooler heat exchanger is coupled to an input of the first load;
• and
• the subcooler heat exchanger is coupled to an input of the expansion valve;
• during a first mode of operation:
• the subcooler heat exchanger is configured to direct the refrigerant from the flash tank to the input of the first load;
• the first load configured to use the refrigerant from the subcooler heat exchanger to cool a first space proximate the first load;
• the second load configured to use the refrigerant from the subcooler heat exchanger to cool a second space proximate the second load;
• the first compressor configured to compress the refrigerant from the first load;
• and
• the second compressor configured to compress a mixture of the refrigerant from the first compressor and the refrigerant from the second load;
• and
• during a second mode of operation:
• the subcooler heat exchanger configured to:
• direct the refrigerant from the flash tank to the input of the expansion valve;
• generate a heated refrigerant by transferring heat from the refrigerant from the flash tank to the refrigerant from the expansion valve;
• direct a first portion of the heated refrigerant to the input of the first load;
• and
• direct a second portion of the heated refrigerant to the first compressor;
• the first compressor configured to:
• compress the heated refrigerant from the subcooler heat exchanger;
• and
• direct the compressed refrigerant from the subcooler heat exchanger to the first load to defrost the first load.