ACR Journal

December 2020 | January 2021 COMPRESSORS 26 Volume 7 No.1 Work is going on, at pace, within the refrigeration sector to bring compressor technology up-to-speed with both the new global regulatory environment and the demands of increasingly eco- friendly consumers. Much of this work however, is the subject of NDAs or being undertaken by large international organisations who have little incentive to divulge any details of their research and development, but it is possible to discern the key drivers. The environmental issues driving change in refrigeration are already well- documented with the sector already under heightened scrutiny for its contribution to global energy consumption – roughly 15% of peak electricity demand according to the IEA. Not unrelated are the tightening regulatory pressures, including the Compressors on frontline in climate battle The refrigeration sector is being disrupted like never before and the compressor technology used is front and centre in the drive for change, says Nicol Low, Chief Operating Officer at Edinburgh-based manufacturer Vert Technologies. Montreal Protocol that outlawed the use of chlorofluorocarbons, and the resulting Kigali Amendment that tightened restrictions further, specifically the use of hydrofluorocarbons (HFCs), which entered into force in January 2019. On a local level, UK businesses must also ensure compliance with the F-Gas regulations. In all cases, the expectation that is that restrictions will only tighten further. Higher pressure demands The issues of energy consumption and environmental impact are not unrelated, in that high pressures are needed to get the best out of the new refrigerants that are replacing those on the banned list. Some of the easy to compress refrigerants, such as R404A, R410A and R134A, also tend to be those with some of the highest global warming potential (GWP) values. Those with a lower GWP, such as natural refrigerants including ammonia or CO 2 , are understandably better for the environment, but also have much higher pressure demands. The central issue for the refrigeration OEMs is that their products require a variable load and variable temperatures, what we would describe as a “big operating window”. With normal compressor technology there is a sweet spot in terms of flow and rpm that oœers the best energy ežciency, but often standard sized compressors are operating outside that sweet spot, which negatively impacts on performance. Traditional compressor technology uses rotating screws placed side-by-side to generate the compression eœect, but Vert believes the company has discovered a better way. We’ve developed what we term a Conical Rotary Compressor (CRC) that uses rotors turning in the same direction at diœerent speeds to compress the fluid as it travels down the conical screw. compressprs.indd 26 03/12/2020 11:55