COMPRESSORS


HFCs with a global warming potential (GWP) of 2500 or above. Consequently, UK businesses are legally required to make their operations more sustainable, or risk a fine of up to £200,000 or more. With the regulations likely to tighten further, the refrigeration sector needs to innovate if it is to keep ahead of the curve.


The F-Gas ban


Aspects of the F-Gas ban include the phasing out of high-GWP refrigerants such as R134A, R410A and R404A, which are easier to compress than other mediums. This is part of a larger effort to curb HFC use by 79 per cent before 2030. Though undoubtedly welcome news from an environmental perspective, this phase-out does raise concerns and challenges for the refrigeration sector.


Specifically, removing high-GWP refrigerants from widespread use means companies will have to use low-GWP alternatives like ammonia and carbon dioxide. Though undoubtedly greener than refrigerants like R134A, R410A and R404A, these media require high absolute pressure requirements and high- pressure ratios to effectively compress them. For organisations using traditional compressor technologies, this can present a number of operational issues. Because media like ammonia and carbon dioxide need to run at higher pressure, companies may need to daisy-chain compressor units in order to reach the levels required for effective use. This, in turn, can lead to further Capex spending expanding existing systems, and additional OpEx costs keeping these units running. Such a situation is not ideal, especially in a business landscape where budgets may have been significantly constricted by the pandemic. Consequently, OEMs and design engineers are developing new approaches to compression to help the adoption of low-GWP refrigerants at scale – an ambition previously obstructed by these costs and logistical issues.


Quiet and efficient


A key priority for refrigeration OEMs is ensuring their products are compatible with varying loads and temperatures. Yet with traditional compressor technology, energy efficiency can be impaired by the fact is has to work within such a large operating window. Flexibility in operation is important to get the best from these low global warming refrigerants.


Acoustic performance represents a further area of concern for traditional compressor


www.acr-news.com


technology, alongside energy efficiency and sustainability. Because of the high pressures required, often the only compressor choice is piston-based. Yet these are often bulky, and can be loud during operation. While not physically harmful for customers, this side- effect can make products seem less attractive.


Conical rotary compressor technology One innovation that can solve these issues is the Conical Rotary Compressor (CRC) from Vert Technologies. Using one rotor placed inside another, and with both turning in the same direction to compress the refrigerant as it travels down the conical screw, the CRC can deliver high pressures, alongside low-vibration and low-noise performance. This is in contrast to traditional screw compressor solutions, which generate compressed air by placing rotating screws side-by-side. Crucially for refrigeration OEMs, the rotor geometry of the CRC can be optimised to suit both the required medium and application. As such, the compression ratio can be changed to suit the specific and exceptionally high pressure requirements required in the sector. Optimisation like this allows the CRC to achieve a compression ratio of 25:1, meaning it ideal for use with low-GWP refrigerants, and well-placed to help the sector adhere to increasingly rigorous environmental legislation.


Acoustic performance and scalability Furthermore, because this technology is scalable, the compressor can be sized for the requirements of the application without worry of a performance penalty. The reason for this scalability is Vert’s patented proprietary software, which enables the alteration of the air compressor’s geometry to suit factors such as flow rate, pressure, power requirements and size. To that end, air compressor trials have been performed from 40mm long 80W compressors, up to 500mm long industrial units with a 13kW capability. Because of the rotary kinematics, acoustic performance is also best in class, with the CRC enjoying lower noise levels than traditional reciprocating compressor models, all while generating higher pressures than scroll systems. For example, a 1.5kW air compressor can deliver 15 bar(g) pressure and an air flow of 200 lpm but with only 62 dB(A) noise before any sound dampening materials are added. With the refrigeration sector currently in a period of regulatory change, and with that only set to get ever tighter, it is key that


companies take account of the trends behind this. Eco-conscious consumers increasingly expect sustainable and energy-efficient units, and with stringent environmental legislation increasingly making such concerns a necessity, innovative solutions must be identified and implemented. Technologies such as the CRC offer a way to help the sector adapt to these looming priorities, and enable solutions fit for the future.


May 2021 35


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48