Energy and greenhouse gases

Common Refrigerants and Selection Considerations

2014-12-31 10:58:10 | Lượt xem: 3534 | Energy and greenhouse gases

An overview of NH₃, R12, R22, R134a, R143a and R410A, with considerations for efficiency, environmental impacts and selecting a refrigerant appropriate to the system.

A refrigerant is the working fluid in a refrigeration cycle. It absorbs heat where cooling is required and releases heat elsewhere. In a vapour-compression system, it circulates through the compressor, condenser, expansion device and evaporator.

Knowing the refrigerant in use helps a business assess performance, maintenance needs, safety and retrofit options during an energy audit.

Refrigerant cylinders and system-inspection equipment — Refrigerants and refrigeration-system inspection equipment

Commonly discussed refrigerants

Refrigerant	Characteristics and considerations
NH₃ — ammonia (R717)	Used in many industrial refrigeration systems. Toxicity, leakage and material compatibility require control; design and operation must be handled by competent personnel.
R12 — CFC	An older refrigerant that depletes the ozone layer. When servicing legacy equipment, identify the refrigerant and follow applicable recovery and maintenance requirements.
R22 — HCFC	Formerly widespread in air-conditioning and refrigeration. HCFCs are subject to phase-out arrangements; check current requirements and the manufacturer’s retrofit guidance.
R134a — HFC	Chemical formula CF₃CH₂F. Used in refrigeration and air-conditioning applications designed for it. It does not deplete ozone but still has climate impacts.
R143a — HFC	A component of certain refrigerant blends. The name of an individual component does not mean it can directly replace a blend in equipment.
R410A — HFC blend	Used in equipment specifically designed for it. Its operating pressure is substantially higher than R22, and it is not a drop-in replacement for an R22 system.

Environmental impacts and safety are different considerations

Ozone-depletion potential and global-warming potential are different indicators. A refrigerant that does not damage ozone can still affect the climate when released. UNEP distinguishes the HCFC phase-out from the HFC phase-down under the Montreal Protocol and Kigali Amendment.

Descriptions such as ‘non-toxic’ or ‘non-flammable’ should not be treated as absolute guarantees for every operating condition. Consult the safety data sheet, equipment documentation and installation requirements.

What should be checked when selecting or changing a refrigerant?

The specified refrigerant, charge quantity and lubricant.
Compressor and material compatibility, operating pressures and protective devices.
Ventilation, leak detection, refrigerant recovery and maintenance personnel’s competence.
Operating efficiency, required temperatures, life-cycle costs and availability.
Current Vietnamese requirements for refrigerant management, import, use and recovery.

Do not mix or change refrigerants merely because another product costs less. Evaluate conversion options for the particular system using the technical documentation and safety requirements.