May 2021

26 | Plant & Works Engineering www.pwemag.co.uk May 2021 Energy & Environmental Management Focus on: HVAC Type Refrigerant ODP GWP* Synthetic CFC R-12 1 Very High 10,910 HCFC R-123 0.012 Low HFO R-1234ze 0 Ultra-Low 1 HFC R-134a 0 High 1,430 HCFC R-22 0.05 High 1,810 HFC R-32 0 Medium 675 HCFC R-401a 0.027 Medium HFC R-404a 0 Very High HFC R-407a 0 High HFC R-407c 0 High HCFC R-408a 0.016 Very High HCFC R-409a 0.039 High HFC R-410a 0 High 2,090 HFO R-454b 0 Low 466 HCFC R-502 0.18 Very High HFC R-507 0 Very High HFO R-513a 0 Medium 631 Natural Isobutane HC R-600a 0 Ultra-Low Ethane R-170 0 Ultra-Low Propane R-290 0 Ultra-Low CO 2 R-744 0 Ultra-Low 1 Ammonia R-717 0 None Water R-718 0 None *Source; Values for 100-year global warming potential (GWP) from IPCC Fourth Assessment Report however is an easier refrigerant to handle and offers similar properties to R-410a, making it a cost-effective & easy to use solution in new equipment without major modifications being necessary, ideal for industrial process applications. R-454b also has a lower GWP of 466 compared to R-32 at 675 and has an ozone depletion potential (ODP) of zero. Operating pressure requirement of new refrigerants While the next generation of refrigerants balance the needs of safety and reduction in carbon footprint, the new trade off is the development and cost of the equipment to cope with the increased pressures required for these refrigerants to work. As a direct replacement for R-410A, R-454B operates at a slightly lower pressure where as R-32 requires a slightly higher pressure. chlorine content, so their ODP is essentially zero. Global Warming Potential (GWP) is the heat absorbed by any greenhouse gas in the atmosphere, as a multiple of the heat that would be absorbed by the same mass of carbon dioxide (CO2). GWP is a measure of how environmentally detrimental refrigerants can be relative to C02 which has a GWP of 1.0 New low GWP refrigerants While the EU market was 71% R-410a for new equipment sold in 2020, HFC HFO Blend HFC/HFO Natural R-410a R-407c R-134a Others R-1234 ze Others R-513a Others 0% 71% 1% 10% 12% 3% 0% 1% 2% 1 (No Flame Propagation) 2 (Lower Flammability) 3 (Higher Flammability) A (lower toxicity <400ppm) A1 – inc. CFC’s R-718 (Water) R-744 (CO2) R-22 R-410a R-407c R-513a R-1234zd A2L - inc. HFO’s R-32 R-454b R-1234yf R-1234ze A2 - inc. HFC/ HCFC’s R152a A3 R-290 (Propane) R600a (Isobutane B (higher toxicity) B1 R-123 B2L R-717 (Ammonia) B2 B3 R-1140 Source; Eurovent 2020 total Europe Next generation refrigerants deliver improvements in the coefficient of performance (COP), the ratio of useful heating or cooling provided to work required or energy usage of the compressor. This comes with a slight flammability trade-off having some implications on chiller placement and maximum charge (hence capacity). It also means components need to be compatible with flammable refrigerants, to ensure they can’t be considered an ignition source. Evap42 ˚ F (5.5 ˚ C) ˚ F (24 ˚ C) Cond97 ˚ F (36 ˚ C) new lower GWP refrigerants such as R-454b are poised to take over from 2021.R-454b is an HFO (Hydro Olefin) refrigerant made by blending the single component R-32 refrigerant with R-1234yf giving some unique advantages. R-32 on its own has a high discharge temperature which can limit its operating envelope without some type of injection. R-454b Ozone Depletion Potential (ODP) and Global Warming Potential (GWP) All refrigerants have an Ozone Depletion Potential (ODP) and Global Warming Potential (GWP) rating. The Ozone Depletion Potential (ODP) is the relative amount of degradation to the ozone relative to R-11 (or CFC-11) being fixed at an ODP of 1.0. It is the ratio of global loss of ozone to the global loss of ozone from CFC-11 of the same mass. Hydrochlorofluorocarbons have ODPs mostly in range 0.005 - 0.2 due to the presence of the hydrogen which causes them to react readily in the troposphere, therefore reducing their chance to reach the stratosphere where the ozone layer is present. Hydrofluorocarbons (HFC) have no *Richard Payne is marketing director at ICS Cool Energy Group