CHILLERS
Cooling challenges
Andy Legg, head of cooling at Swegon Group UK, shares his opinion on how the future of chillers will unfold.
For the past decade the two most widely used HFC refrigerants for HVAC and process cooling chillers have been R410a for scroll and R134a for screw and centrifugal compressors. These have GWP’s of 2088 and 1430 respectively. Assuming there is no growth in the chiller market between now and 2030, we need to hit an average GWP of less than 500. However, we expect to see demand increase, which means that 150 is more likely to be the end destination.
W
hat a great time to be a chiller manufacturer. Having been involved in the chiller industry for over 30
years, Swegon has seen the market and products evolve significantly during this time. With recent legislation, a whole new set of challenges is heading our way, shaking up the industry and driving new innovations – not dissimilar to the car industry having emission targets to achieve. The first is the widely known F-Gas regulations, which aim to phase down the amount of HFC refrigerants used across Europe. R22 was banned in 2000 as part of the reduction in ozone depleting substances, so we are familiar with the harmful effects refrigerants can have on our environment and the need to legislate them out of use. The emphasis now is to target those refrigerants that contribute to global warming when released into the atmosphere. Unlike the R22 ban, F-Gas is imposing a tapered phased down across Europe. Whilst not targeting any specific gas, it is looking holistically at the total CO2
Swegon believes that demand for chillers will increase as water will become more favourable as the heat transfer medium of choice over DX refrigeration systems, as the lower the GWP, the higher the flammability of the refrigerant becomes. With greater emphasis on fire safety, piping a mildly flammable refrigerant around a building or even into a plant room will become less attractive. The beauty of chillers is that they are packaged units containing a lot less refrigerant than a DX or hybrid system and can be located outdoors in the open.
Development of new refrigerants is at an all-time high, with every manufacturer looking for that elusive low GWP, low flammability combination. Currently, screw and centrifugal compressors can now use HFO R1234ze and R513a with 0.9 and 631 GWP respectively, with the latter being non-flammable. This means, for cooling capacities above 250kW, there is now a market-ready solution. Swegon had the benefit of producing R1234ze chillers for the Swiss market back in 2014, and so has proved that the refrigerant is fit for purpose and able to manage the mild flammability risk.
equivalent as the benchmark. The first big drop of 37% came into force at the beginning of the 2018 and has already resulted in shortages and big price hikes.
24 August 2018
With less refrigerant on the market, manufacturers are also having to adopt new technologies such as micro-bore copper and micro-channel aluminium condenser coils and spray-flooded evaporators.
An area expected to see growth is commercial
heat pumps. Their adoption in the residential market has been gaining traction for several years, but now attention is turning to the commercial market where, for years, chillers and separate boilers have been the default choice. Typically, a reverse cycle heat pump only costs 20% more than its chiller counterpart. But for that you get an asset you can use all year, not just for our short summers. If you consider also that the latest four-pipe chiller heat pumps can offer cooling and heating together, or independently, it takes away the need for separate boilers.
Another piece of EU legislation that was enacted at the beginning of 2018 was the ErP EcoDesign Directive 2016/2281 Tier 1, with the purpose of driving up the part load efficiency of chillers and heat pumps used for comfort and process cooling. Practically speaking, it means that to comply most manufacturers have had to drop or modify some of their products – hence the introduction of larger condenser coils, EC fan motors, multiple and inverter driven compressors.
By the time Tier 2 comes along in 2021 with even higher thresholds, it is likely that all compressors will need to be inverter driven. The days of on-off scroll and standard screw compressors are numbered.
The convergence of F-Gas and EcoDesign creates other challenges too, such as footprint. The market for retrofits is huge, with thousands of old chillers coming to the end of their working life. But will the new chillers fit the available space? It is possible that with increased coil sizes and new refrigerants, they might not. So, demand for water cooled units with bespoke remote dry coolers could be another alternative.
The good news is that these regulations are good for the environment and our clients’ energy bills. We just need to make sure we present all the facts to our clients to help them make the right decision for them.
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