ACR Journal

CMYK / .ai CMYK / .ai CMYK / .ai acrjournal.uk 19 REFRIGERANTS a refrigerant we realise there are many advantages. Let’s see few of them. 1) Compressor gas discharge temperature R290 and especially R600a (isobutane) have a lower discharge temperature than other refrigerants. The benefit of a low discharge temperature has a positive effect on compressor materials, components and stability of the oil. If the discharge gas temperature is too high, decomposition of lubrification oil occurs. 2) Higher heat transfer, low-pressure ratio Thanks to the excellent thermodynamic properties of propane, such as the higher heat transfer and low-pressure ratio (condensation to evaporation pressure) it is possible to design appliances with smaller heat exchangers , this could lead to a reduction in physical space requirements, making planning and installation easier. 3) Lower density The density of propane is much lower than of fluorocarbons (less than half than of R134a and R410a), and this, combined with higher heat transfer, gives a much lower refrigerant charge as a result. A number of analysis tests have been carried out in this regard using reciprocating compressors; this showed a potential half R290 charge compared with R32 and almost one third compared with R134a. 4) Efficiency comparison Comparisons to R410A EERs for R290 and R600a are between 5% and 12% higher . This simplistic comparison of EERs is indicative of the strong potential for energy efficient operation of HC systems. 5) Compressors envelope comparison for different refrigerants In this case we can see how propane is an efficient and flexible refrigerant in different operating conditions. It can go from very low evaporating temperature to high condensing temperatures. This makes possible to design a wide range of products from chillers (high, mid and low temperature) to heat pumps. Euroklimat started using propane in 2006 on a wide range of R290 process and comfort cooling units up to 500kW cooling capacity, and later in 2018 extending to the R290 ASHP range up to 200kW heating capacity. However, time waits for no one and Euroklimat launched a 700kW heating capacity unit in early 2022. Overall, these comparisons can demonstrate that smaller sizes of compressors can be used with propane, as well as heat exchangers. Even considering medium GWP refrigerants such as R513a and low GWP options such as R1234ze and R1234yf, the comparison is in favour of R290, even considering the same reciprocating compressor model. Early in July of this year I was in Milano MCE and I met with a number of scroll compressor manufacturers. They all declared: “Sure, we’re ready with R290”. Appreciating the massive effort required, this is not an easy process and in fact only the smallest compressors have been released. In many cases they are used for residential or small commercial HP projects. Effort and of course investment is required to develop a widely available commercial HP range, 20-30-50HP, tandem and trio configurations, high temperature versions for DHW production, and these are not yet available. But the demand to reach net zero and the obvious climate changes we have all experienced over the last few years mean we need it and we need it now. In the meantime, we enjoy the good old reciprocating compressor , so reliable, so efficient, full Inverter. In conclusion, one of the ways for the HVAC industry to contribute to saving our planet is to promote an increasingly consistent use of natural refrigerant fluids such as propane R290 (GWP=0.02) and isobutane R600a (GWP=0.006). The direction is well marked, the industry is definitely on the way and excellent results are expected soon from all major players in the market. https://www.euroklimat.it/ Euroklimat VHERA R290 heat pump