Common Refrigerants: An Overview for Energy Audits

A refrigerant is the working fluid that transfers heat through a refrigeration cycle. Identifying the correct refrigerant is an important part of evaluating cooling equipment, performance and maintenance needs.

This historical list is not exhaustive. Before purchasing refrigerants, confirm current restrictions and phase-out requirements for the intended application.

Ammonia — NH₃, R717

Ammonia has long been used in industrial refrigeration, including large cold stores and ice production. It can provide effective thermal performance, but toxicity, flammability characteristics and material compatibility require specialized system design and operation. It is not interchangeable with refrigerants used in typical domestic air-conditioning equipment.

R12 — CFC refrigerant

R12, with the formula CCl₂F₂, was widely used in older refrigerators and other equipment. Its ozone-depleting characteristics are central to the restrictions on this refrigerant. Existing equipment and recovered refrigerant require handling under applicable rules.

R22 — HCFC refrigerant

R22, CHClF₂, was extensively used in air conditioning and medium-capacity refrigeration. It has ozone-depleting potential. Check applicable phase-out schedules and restrictions for new equipment, imports, production and servicing.

R134a — HFC refrigerant

R134a, CF₃CH₂F, has been used in refrigeration and automotive air conditioning as an alternative to R12 in suitable designs. It does not contain chlorine, but its global-warming impact is relevant to refrigerant selection and regulatory controls.

R143a — HFC blend component

R143a, CF₃CH₃, is used in refrigerant blends including R404A and R507A. The hazards and handling requirements of a blend must be assessed from its own safety data sheet, rather than inferred from one component.

R410A — refrigerant blend

R410A is a blend of R32 and R125 in equal mass proportions, widely used in compatible air-conditioning designs. It operates at higher pressure than R22 in comparable applications and is not a direct replacement for an R22 system.

Absence of ozone-depleting chlorine does not mean absence of climate impact or handling hazards. Components, tools and procedures must be rated for the refrigerant and operating conditions.

What to check during an energy audit

• Equipment nameplate and specified refrigerant.
• System condition, leakage history and maintenance records.
• Operating temperatures, pressures and energy performance.
• Compatibility of any proposed replacement or retrofit.
• Applicable environmental rules, recovery arrangements and competent servicing support.

Use the manufacturer’s technical information and the refrigerant safety data sheet. See the Danfoss refrigerant resource centre for further technical context. Refrigerants should not be mixed or substituted without an approved engineering assessment.