IntermediateTopic 37 of 105Thermodynamics & Fluids
Refrigerants
Working fluids chosen for thermodynamic properties and environmental impact.
In depth
Desirable properties: suitable pressures at operating temperatures, high latent heat, chemical stability, non-toxicity and low global warming potential (GWP) and ODP. Examples: R134a, R410A, R32, R290 (propane), R744 (CO₂), ammonia. Regulations phase down high-GWP gases.
Key points
- Safety classes A1–B3 for toxicity and flammability
- Glide in zeotropes
- Lubricant compatibility
ExampleR-600a replaced R-134a in many fridges for lower GWP.
What is Refrigerants?
Working fluids chosen for thermodynamic properties and environmental impact.
Why is it important to understand refrigerants?
Refrigerants must boil and condense at useful pressures while having low environmental impact, so their choice is a balance of performance and regulation.
What properties matter for a refrigerant?
Suitable saturation pressures, high latent heat, good stability, safety in terms of toxicity and flammability, and low environmental impact.
Why are some refrigerants being phased out?
Many older refrigerants have high global warming potential or harm the ozone layer, so international agreements limit their use.
How is Refrigerants used in practice?
Typical applications include choosing a low global warming potential refrigerant for a new heat pump, selecting a refrigerant with safe pressure for a domestic appliance and understanding why older refrigerants are being phased out.
What should I learn before Refrigerants?
Study "Vapour compression refrigeration" first (topic 36 of 105 in Thermodynamics & Fluids). It covers the groundwork this topic builds on.
What are the key points of Refrigerants?
Safety classes A1–B3 for toxicity and flammability. Glide in zeotropes. Lubricant compatibility.
Can you give an example of Refrigerants?
R-600a replaced R-134a in many fridges for lower GWP.
What comes after Refrigerants?
The next topic is "Air conditioning and psychrometrics", which builds directly on this one.
How difficult is Refrigerants?
It is classed as Intermediate in Thermodynamics & Fluids (topic 37 of 105). It is an intermediate topic. Work through the beginner topics in Thermodynamics & Fluids first.