Quick answer
A structured method for choosing between NH₃, CO₂ transcritical, CO₂/NH₃ cascade and HFC/HFO systems on total cost of ownership, safety, regulation and operational fit — not on what a preferred supplier happens to offer. Run a total cost of ownership model on at least two architectures against the same load profile, tariff and lifecycle. Include: capex; annual electricity at design load and part load; refrigerant purchase and eventual retrofit; maintenance and skills market; insurance premium; regulatory transition cost over the design life; and residual value at…
Key takeaways
- How to actually decide Run a total cost of ownership model on at least two architectures against the same load profile, tariff and lifecycle.
- Common mis-selections Choosing HFC because the plant is small — even when the site is committed to a 25-year lifecycle inside a jurisdiction phasing the refrigerant out.
Reviewed: Feb 2026 · ColdMatch Group
Refrigerant selection is the single design decision that most shapes the next 20 years of a cold storage facility — energy bill, refrigerant risk, retrofit exposure, insurance, staffing and eventual decommissioning cost. It is also the decision most often made by default, because it is easier to accept a supplier's recommendation than to model alternatives. the pillar guide on planning before equipment argues that the correct answer depends on requirements, not on preference. This article gives the framework.
The four viable architectures
- Ammonia (NH₃, R717) — low-charge, flooded or pumped. Excellent efficiency, zero GWP, restricted by safety zoning.
- CO₂ (R744) transcritical — strong in cold climates and multi-zone DCs; needs adiabatic gas coolers, ejectors or parallel compression in hot climates.
- NH₃/CO₂ cascade — combines high-side efficiency of NH₃ with the safety profile of CO₂ on the load side.
- HFC / HFO DX — appropriate for small chilled rooms and retrofits, but exposed to F-gas / HFC phase-down over a 15–20 year horizon.
How to actually decide
Run a total cost of ownership model on at least two architectures against the same load profile, tariff and lifecycle. Include: capex; annual electricity at design load and part load; refrigerant purchase and eventual retrofit; maintenance and skills market; insurance premium; regulatory transition cost over the design life; and residual value at decommissioning. The winner is the architecture that wins on lifecycle cost after adjustment for operational risk — not the one with the lowest quoted capex.
Common mis-selections
Choosing HFC because the plant is small — even when the site is committed to a 25-year lifecycle inside a jurisdiction phasing the refrigerant out. Choosing CO₂ transcritical in a hot climate without pricing the parallel compression or ejector work required to remain efficient. Choosing NH₃ on a site with no trained refrigeration workforce within 300 km. Each is a governance mistake, not a technology mistake.
Related planning resources
- the pillar guide on planning before equipment — why the requirements determine the refrigerant, not vice versa.
- Cold storage energy strategy — how each refrigerant choice interacts with envelope, controls and tariff.
- Cold storage total cost of ownership — the number the refrigerant decision should be judged on.
- Explore the Refrigerant Decision Checklist and the Refrigerant TCO Calculator.
Run the numbers
Calculators for this project type
Indicative planning figures only — final sizing belongs to the supplier's or consultant's detailed design.
Refrigeration load calculator
Indicative cooling load in kW from room volume, temperature class, insulation and design ambient.
Energy & backup powerEnergy & backup power cost calculator
Annual energy spend from load and running hours, plus the cost of generator hours during outages.
Frequently asked questions
Plan the numbers before you send an RFQ
The reference pages buyers use most before requesting quotes.