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CO2 gas coolers for supermarket and transcritical refrigeration.
CO2 is the low-GWP answer for supermarket refrigeration, and it runs at pressures far above HFC systems. The gas cooler on the roof is where the system rejects its heat, and its approach temperature sets how efficient the whole rack runs on a hot day.
A transcritical CO2 refrigeration system rejects heat through a gas cooler instead of a condenser. Above about 88°F the CO2 does not condense, so the gas cooler cools supercritical gas at high pressure. Coil design and approach temperature drive system efficiency.
What makes it hard.
The problems we size against.
Pressure is high.
Transcritical CO2 gas coolers see far higher pressures than HFC condensers, so tubes and headers are built for it.
Hot days cut efficiency.
When ambient climbs, the gas cooler approach decides how hard the compressors work. Adiabatic options help in hot climates.
The refrigerant rules are changing.
The AIM Act phase-down pushes new stores toward natural refrigerants like CO2.
How the system works.
From the load to the air, in four steps.
- Cases and walk-ins absorb heat.
Display cases and storage rooms cool product and load the CO2 system.
- Compressors raise the pressure.
The rack compresses CO2 to high pressure and temperature.
- The gas cooler rejects heat.
On the roof, fans pull air across the gas cooler coil.
- CO2 returns to the store.
Cooled CO2 expands and returns to the cases.
The equipment.
What goes into a supermarket CO2 system.
Air-Cooled Heat Exchangers
Industrial Unit Coolers
CondensersQuestions about supermarket CO2
What is a CO2 gas cooler?
It is the heat rejection coil of a transcritical CO2 system. It does the job a condenser does in an HFC system, but cools supercritical CO2 gas at high pressure instead of condensing it.
Why are supermarkets moving to CO2?
CO2 has a global warming potential of 1, and the AIM Act is phasing down high-GWP HFCs. CO2 is non-flammable and widely used in new supermarket systems.
How is a gas cooler rated?
The published rating is gas at 235°F in and 1,363 psi, leaving at 93°F, with 90°F ambient air. Each selection is run at your conditions.
Send the heat load.
Loop temperatures, flow and site. A sized selection comes back.