CHILLERS
T his is unlikely to be the case with basement / built in chillers, Multi splits (including VRF / VRV) nor Close Control systems.
R407C
With no new design or manufacture of such e quipment for several years there is little
i ncentive for refrigerant manufacturers to develop y et more blends using low GWP base components f or a diminishing market which is repair only. For smaller systems then replacement is the likely solution, but many chillers with decent physical service life do exist and for these short term service repairs will become increasing non supportable.
R etrofit to R134a and its characteristic HFO / low GWP blends is a real possibility, although the engineering needs to closely look at not only Risk Assessment safety factors, but also how the capacity of the equipment will be maintained.
R134a
Already widely used in many larger chillers R134a is one of few refrigerants offering both Low GWP and some with Low / No flammability solutions. R134a is also notably lower operating pressure than R407C and particularly that of R410A.
This has secondary advantages for use in older equipment where it can reduce operating pressure stresses.
R 134a also has the crucial advantage that a lready several well established replacement r efrigerants offering similar operating characteristics are available.
R407C systems can be retrofitted to R134a wit h either a loss of capacity or provision or this can b e substantially reduced by increasing compressor c apacity, and this can be achieved not only by l arger compressors, but also by assigning Inverter d rives to existing (screw or scroll) compressors to get more capacity.
Use of R134a on such systems also provides a substantial element of payback because the energy savings achieved can be enormous, indeed will pay for the entire cost of upgrade most within fi ve years and some in as few as two years.
Flammability
The new edition of EN378 will include the US established A2L Low flammability category, but what will this actually mean ?
I t will be important to closely study EN378 w hen deciding to use any flammable refrigerant, and those who do not should be aware that if
there is an incident, any subsequent investigation will be looking at design responsibility and with it culpability. If you are the customer service m anager offering a retrofit of an existing system to some fancy blend of HFO intended for use in new design equipment only, but to an existing system then make sure you have a full understanding of what you are doing and the risks you may otherwise unwittingly be taking. In summary it is clear that the new range o f refrigerants being provided will pose some important technical and safety considerations, and the requirement to act is closer than many may realise.
Our Industry is still providing an immense volume of new equipment using refrigerants that w ill not be available, and the reducing pool will not be large enough for us all to swim in in a remarkably short period of time.
This article has stretched beyond chillers into Split and Multi split equipment all drawing from t he same reducing pool of refrigerant. The choice for new equipment will soon likely be dictated b y what refrigerant is available, and this might not be the preferred choice. Service users may also face a critical issue of simple non availability when they need it most.
Daikin Applied
29
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