Overview
The EU F-Gas Regulation 517/2014 phase-down is driving a rapid transition away from high-GWP HFC refrigerants. Technicians must understand the alternatives available, their benefits, limitations, and safety implications. EU Implementing Regulation 2015/2067 requires candidates to demonstrate knowledge of natural refrigerants, low-GWP synthetic options, and heat pump technology as part of their certification.
Natural Refrigerants
Natural refrigerants have zero or near-zero GWP and have been used in refrigeration for over a century.
- CO₂ (R-744) — GWP of 1. Non-flammable, non-toxic. Operates at very high pressures (up to 120 bar on the high side in transcritical systems). Widely used in supermarket refrigeration and heat pump water heaters. Requires components rated for high pressure.
- Ammonia (R-717) — GWP of 0. Excellent thermodynamic properties and high energy efficiency. Toxic (B2L safety classification) and mildly flammable. Predominantly used in large industrial systems with dedicated plant rooms and safety systems.
- Hydrocarbons (R-290 propane, R-600a isobutane) — GWP of 3 (R-290) and 3 (R-600a). Excellent efficiency. Highly flammable (A3 safety classification). Charge limits apply under EN 378 — typically limited to small commercial and domestic systems. Strict requirements for electrical components, ventilation, and signage.
Low-GWP Synthetic Refrigerants
- HFOs (hydrofluoroolefins) such as R-1234yf (GWP 1) and R-1234ze(E) (GWP < 1) are mildly flammable (A2L) synthetic alternatives now used in automotive AC, chillers, and some commercial systems.
- HFO/HFC blends such as R-454B (GWP 466), R-454C (GWP 148), and R-513A (GWP 573) offer lower GWP than traditional HFCs while retaining familiar operating characteristics and reduced flammability risk.
- Technicians must check that existing equipment is compatible before retrofit — lubricants, seals, and pressure ratings may differ.
Heat Pumps
Heat pumps use the same vapour-compression cycle as refrigeration but are designed to deliver heat rather than cooling. They are a key technology for decarbonising building heating.
- Air-source heat pumps (ASHP) extract heat from outdoor air. Performance decreases in very cold ambient conditions.
- Ground-source heat pumps (GSHP) extract heat from the ground via buried loops. More stable performance year-round but higher installation cost.
- The Coefficient of Performance (COP) measures efficiency: a COP of 3 means 3 kW of heat delivered for every 1 kW of electrical input.
- Reversible heat pumps can provide both heating and cooling by reversing the cycle via a four-way reversing valve.
Safety Classifications
Refrigerant safety is classified under ISO 817 using a letter-number system:
- A = lower toxicity; B = higher toxicity.
- 1 = no flame propagation; 2L = lower flammability; 2 = flammable; 3 = higher flammability.
Exam Tip: Know the GWP, safety classification, and typical application for each major alternative refrigerant. Questions often ask you to select the most appropriate refrigerant for a given scenario based on charge size, location, and safety requirements. Understand why the EU phase-down is driving the shift and which regulations restrict high-GWP options.
