Cooling system

A system comprising:

• a flash tank configured to store a refrigerant;
• a first load configured to use the refrigerant from the flash tank to cool a first space proximate the first load;
• a second load configured to use the refrigerant from the flash tank to cool a second space proximate the second load;
• a first compressor configured to:
• compress the refrigerant from the first load during a first mode of operation;
• and
• compress the refrigerant from the second load during a second mode of operation;
• a second compressor configured to compress a mixture of the refrigerant from the first compressor and the refrigerant from the second load during the first mode of operation;
• a first valve disposed between the second load and the first compressor, configured to:
• close during the first mode of operation;
• and
• direct the refrigerant from the second load to the first compressor during the second mode of operation;
• and
• a second valve configured to:
• close during the first mode of operation;
• and
• direct the compressed refrigerant from the first compressor to the first load during the second mode of operation to defrost the first load.

A method comprising:

• storing, by a flash tank, a refrigerant;
• during a first mode of operation:
• using, by a first load, the refrigerant from the flash tank to cool a first space proximate the first load;
• using, by a second load, the refrigerant from the flash tank to cool a second space proximate the second load;
• compressing, by a first compressor, the refrigerant from the first load;
• and
• compressing, by a second compressor, a mixture of the refrigerant from the first compressor and the refrigerant from the second load;
• and
• during a second mode of operation:
• using, by the second load, the refrigerant from the flash tank to cool the second space proximate the second load;
• directing, by a first valve disposed between the second load and the first compressor, a flash gas from the flash tank to the first compressor;
• compressing, by the first compressor, the flash gas from the flash tank before the flash gas returns to the flash tank;
• and
• directing, by a second valve, the compressed flash gas from the first compressor to the first load to defrost the first load.