CO₂ transcritical refrigeration monitoring for supermarkets.
More grocers are installing transcritical CO₂ (R-744) racks as lower-GWP refrigerant rules tighten. CO₂ systems run at much higher pressures than HFC racks and behave differently in hot weather and during power loss. Kalder watches them around the clock, with the same staffed alarm desk, KalderIQ analytics and remote access we provide for every rack.
Why CO₂ racks need closer watching.
CO₂ has a critical point of about 87.8°F (31°C). On warm days a transcritical rack rejects heat above that point, pressures on the high side run well over 1,000 psi, and small control problems show up quickly as lost capacity. When the rack stops, the charge warms and standstill pressure rises. If pressure is not held, relief valves can vent refrigerant, and the rack has to be recharged before it can recover.
None of that waits for business hours. A power interruption, a tripped compressor or a controller that stops communicating at 2 a.m. needs a person to see it and call someone who can act.
What Kalder watches on a CO₂ rack.
- Critical rack alarms around the clock, answered by our staffed alarm desk
- High-pressure, standstill and power-loss alarms, escalated to your team and contractor
- Compressor distress against the expected operating envelope
- Loss of charge and the pattern of repeat alarms behind it
- Case and walk-in temperatures on the rack’s circuits
- Controller connectivity, so a rack that stops reporting is treated as an alarm
Leaks still matter on CO₂.
CO₂ has a global warming potential of 1, so it falls outside the EPA leak-repair rules written for HFC systems. A leaking CO₂ rack still loses capacity, runs harder and needs recharging, and a large release into an enclosed space is a safety concern. KalderIQ trends the rack’s operating data so a slow loss is found before it becomes a service call. Room-level CO₂ detectors remain the right tool for occupant safety in machine rooms and walk-ins.
Mixed estates on one screen.
Most grocers run CO₂ racks alongside older HFC systems. Kalder monitors both on the same platform, so your team sees every store and every rack in one ranked view, whatever refrigerant it runs.
The proof.
All case studiesCompressor replacements: eleven in two years, then none.
A pattern of repeated compressor replacements became a series of routine service corrections. The same sites reported no replacements in the first year of monitoring.
The controller went silent. KalderIQ noticed.
When the controller stopped reporting, the missing data became the alarm. KalderIQ raised it before the store’s morning started.
The Kalder products behind it.
Common questions
Does Kalder monitor transcritical CO₂ refrigeration systems?
Yes. Kalder provides 24/7 staffed alarm monitoring, KalderIQ analytics and remote controller access for supermarket transcritical CO₂ racks, alongside HFC systems in the same estate.
Why is a power loss more serious on a CO₂ rack?
When a CO₂ rack stops, the refrigerant warms and standstill pressure rises. If pressure is not held, relief valves can release refrigerant and the rack must be recharged before it recovers. Getting a person to respond quickly limits the damage.
Do EPA leak-repair rules apply to CO₂ systems?
EPA’s AIM Act leak-repair rules apply to HFCs and other refrigerants with a global warming potential above 53. CO₂ has a GWP of 1, so those rules do not apply, but finding a slow loss of charge still protects capacity and avoids recharges.
Can you monitor CO₂ and HFC racks together?
Yes. Both are monitored on the same platform and ranked in one view across all your stores.
Further reading.
See your stores the way our alarm desk does.
A 30-minute walkthrough with someone who knows refrigeration. Bring your store list and controller types; we’ll tell you what connects and where we’d start.