As F-Gas and HFC phasedowns come into force, compressor manufacturers are busy testing and qualifying for alternative refrigerants. RAC reports
Tecumseh investigates low-GWP options
Tecumseh has announced its position on the testing of low-GWP refrigerants, with the aim of replacing the high-GWP R404A and R134A.
The firm says that “the effect that HFO refrigerants have on compressor reliability is of extreme importance to Tecumseh.
As previously reported, some HFO blends have been ruled out due to the higher discharge temperatures and negative impact on compressor reliability and life”.
It has released recommendations according to compressor size, and for the under-0.5 HP range of self-contained commercial refrigeration equipment, Tecumseh continues to support R290 (propane).
The manufacturer says that R290 delivers anywhere from a 10 per cent to a 45 per cent improvement in efficiency when compared to R134a.
However, because R290 is classified as an A3 (highly flammable) refrigerant, charge limitations and safety requirements must be taken into consideration, it says.
Typical applications for R290 include beverage coolers, reach-ins, vending equipment and commercial refrigerators and freezers.
Tecumseh says that it continues to support R134a for medium-temperature applications with capacities up to 30 HP as a “mid-term solution”.
But since the US EPA is looking at early phase-out of R134a, it recommends an HFO option. It says that R1234yf is a viable alternative for R134a, but notes that “the trade-off comes in the form of reduced capacity (approx. -5 per cent) and lower efficiencies (approx. -10 per cent) in comparison to R134a. With lower condensing temperatures, R1234yf does exhibit better performance than R134a”.
But the manufacturer also notes that R1234yf is classified as an “A2L” refrigerant, meaning that it is mildly flammable and therefore subject to charge limitations.
Meanwhile, to replace R404A for medium- and low-temperature applications ranging in capacity from 0.5 HP to 30 HP, Tecumseh sees the HFO R452A (which has a GWP of 2140) as an interim solution for R404A.
The manufacturer notes: “R452A offers a 45 per cent reduction in GWP versus R404A; it is classified as an A1 refrigerant (so is not flammable and no charge limitations) and uses the same lubricating oil as R404A.”
The results have been good too, the firm says: “Testing has confirmed that R452A provides nearly the same capacity and efficiency as R404A across an evaporating temperature range of -25 deg C to -10 deg C.
However, for evaporating temperatures below -25 deg C, R452A exhibits a slight reduction in capacity (up to 9 per cent capacity drop at -35 deg C). At a high evaporating temperature (-10 deg C), R452A shows an efficiency increase of up to 5 per cent in comparison to R404A.”
Given the results, together with low discharge temperature, Tecumseh recommends the use of R452A as a mid-term solution in medium and low temperature commercial refrigeration applications.
It adds that “the low discharge temperatures exhibited by R452A are extremely important to Tecumseh, mainly due to our experience with hermetic compressor reliability”.
The manufacturer says that OEM customers interested in obtaining R452A compatible compressors for performance and/or field test samples should contact their Tecumseh sales representative.
In parallel, Tecumseh is evaluating the availability of R452A compatible compressors and condensing units via its network of authorised wholesaler distributors, with a tentative launch date of early 2016.
The manufacturer says it is continuing to devote resources in evaluating its products for use with low-GWP refrigerants, including the determination of a sustainable long-term solution. “We are also continuing to evaluate other interim solutions for R404A where there are opportunities to deliver higher compressor efficiencies without sacrificing product reliability,” it says.
Tecumseh”s recently launched AE and AJ series commercial refrigeration compressors are optimised for use with R290 (propane), while some AE models and the new AJ range are optimised for use with R1234yf. The entire range of Tecumseh fractional HP compressors is compatible with R134a.
Meanwhile, it notes that “all next-generation Tecumseh commercial refrigeration compressors, including the AEX, TC and AK2 series, are being designed for use with the best available eco-friendly refrigerants”.
The manufacturer says that alongside its aim to give customers eco-friendly options, one of its key objective is to limit the number of medium-term refrigerants that can work across the product range and within commercial refrigeration operating temperatures.
In addition, Tecumseh continues to work in conjunction with industry associations AHRI and ASERCOM and affiliated member companies in further evaluation and testing of low-GWP refrigerants.
Danfoss qualifies models for R407A and R407F
Compressor giant Danfoss Commercial Compressors has announced the qualification of its scroll and Maneurop reciprocating compressors for refrigeration for the transitional refrigerants R407A and R407F.
Danfoss says that to support customers in the phasedown of HFCs, it has validated the use of its Maneurop reciprocating MTZ and Danfoss scrolls MLZ models with R407A and R407F refrigerants. The qualification plan encompasses Optyma Plus new generation and Optyma Slim Pack ranges.
In food retail and commercial refrigeration applications, the main refrigerants currently used are R404A and R134a.
However, with a GWP equivalent of 3.8 tons of CO2, R404A will be banned in the future for new equipment, the firm notes, with its availability reduced by at least 30 per cent between now and 2017 due to the implementation of the quota system.
Alternative solutions such as R407A and R407F have a lower carbon footprint and are expected to increase in usage alongside existing refrigerants such as CO2 or hydrocarbons and R134a.
The F-Gas phasedown will apply to commercial refrigerators and freezers, hermetically sealed, stationary refrigeration equipment for temperatures above -50 deg C and multipack centralised refrigerated systems for commercial use with a capacity above 40 kW.
Danfoss says that with partner wholesalers, it will help installers and OEMs in the selection and retrofit when switching to the new refrigerants.
Application guidelines and instructions for the MLZ and MTZ compressors are available at cc.danfoss.com