GIZ study finds minimal cost difference between use of hydrocarbons and F-gases in split ACs
November 17, 2022
A study published by the Gesellschaft für Internationale Zusammenarbeit (GIZ), the German government agency for implementing international cooperation projects, has found that there are minimal technical and cost issues related to the switch from HFCs to low-GWP refrigerants such as hydrocarbons in split air conditioners (ACs).
The study – “Can refrigerants with a GWP below 150 be used for split air conditioners in Europe?” by Dr. Daniel Colbourne, co-owner of Re-phridge, a U.K.-based consultancy – based its analysis on models available on the Eurovent and Keymark databases. It also uses the updated global safety standard IEC 60335-2-40:2022, approved in May; the standard allows greater charges of flammable refrigerants once risk mitigation measures are considered. The study focuses on split ACs below 12kW (3.4TR).
Some of the study’s key findings related to cost for reversible air-conditioning systems (RACS) for domestic use employing low-GWP refrigerants are:
- A switch from R410A to propane (R290) is likely to be cost-neutral.
- A switch from R32 to R290 would likely incur a small incremental material cost (less than €10/US$10.05).
- A switch from R410A to propylene (R1270) is likely to result in a cost benefit.
- A switch from R32 to R1270 would likely incur a negligible incremental material cost (less than €5/US$5.03).
“In all cases, the variation would be less than 1% of the RACS retail price,” the study says. “These also neglect the lifetime costs associated with re-charging or to[p]ping-up of systems, which if accounted for, would yield further cost advantages for R290 and R1270 RACS.”
The report, available in the publication section of the Green Cooling Initiative, focuses on the use of low-GWP refrigerants, especially considering R1270 and R290, among others.
Split ACs are transitioning away from high-GWP refrigerants, such as R410A, and mid-GWP options, such as R32, going for an increased use of natural alternatives. The global adoption of R290 instead of R32 in split systems would avoid up to 0.12°C (0.22°F) of global warming.
Table 1: GWPs, safety classification and LFL of refrigerants under consideration.
| GWP | R410A | R32 | R1270 | R290 | R1234yf | R152a |
|---|---|---|---|---|---|---|
| GWP(100y)1* | 2088 | 675 | [not listed] | [not listed] | 0.5 | 124 |
| GWP(20y)1 | 4340 | 2330 | [not listed] | [not listed] | 2 | 591 |
| GWP(100y)2 | 2256 | 771 | <0.1 | <0.1 | 0.1 | 164 |
| GWP(20y)2 | 4715 | 2690 | <0.1 | <0.1 | 0.5 | 591 |
| Safety class | A1 | A2L | A3 | A3 | A2L | A2 |
| LFL [kg/m3] | - | 0.307 | 0.046 | 0.038 | 0.297 | 0.130 |
1—IPCC 4th Assessment report, AR4 (Chapter 2; Forster et al., 2007); * Regulatory values
2—IPCC 6th Assessment report, AR6 (Chapter 7; Forster et al., 2021)
R1270 and R290 viable alternatives
In addition, the report highlights that:
- All alternative refrigerants can be used, within the charge limits of the revised IEC standard, for the entire RACS capacity range and all seasonal energy efficiency ratios (SEER) up to 12, as well as average, high- and extreme-space thermal loads. Both R1270 and R290 are viable alternatives, the former being preferred for capacities higher than 10kW (2.8TR) due to its higher LFL (lower flammability level).
- Compared to R32, additional material is required for R1270 and R290. The cost implication is relatively small, in the order of a few euros. The cost implication for additional safety features for R1270 and R290 is also only a few euros, especially when considering higher efficiency products.
- Emissions associated with use of the additional materials are negligible, especially when compared with those associated with the lifetime emissions from refrigerants with GWP greater than 150.
- Due to its much greater material mass and high price, the overall cost of R1234yf, especially relative to R32, is high – above that of the European Carbon Trading Scheme – suggesting questionable viability.
These results expand on the European Commission’s analysis of alternatives to fluorinated gases in split ACs, which found national building codes as obstructive to the deployment of low-GWP natural alternatives in the sector. “R290 units provide good energy efficiency and are available at a very modest price increase that would likely disappear if mass produced and marketed at large scale,” concluded the Commission’s analysis.
Haier announced at Chillventa 2022 its air-to-air R290-based system, which will be marketed in Europe as of 2023. The system will compete with both Midea and Clivet, companies that are already marketing this technology in Europe. In addition, the Germany-based Fraunhofer Institute for Solar Energy Systems ISE is developing a heat pump system that can deliver up to 12.8kW of heating with only 124 grams of propane.