Why Low GWP and Natural Refrigerants | Pure Thermal

Why Low GWP and

Natural Refrigerants

It is now becoming accepted best practice to apply Refrigerants within Cooling & Heating Plant that have a Global Warming Potential (GWP) at the lowest practical level to meet the needs of the application.

Ozone-depleting refrigerants (high ODP refrigerants) have in the past been increasingly replaced by HFC refrigerants. Although these refrigerants have an ODP of zero, they still have a high global warming potential (GWP) of over 700 to 2000 and above. Whereas synthetic HFO refrigerants such as R1234ze are now available with a much lower GWP level of 1 (AR5). Alongside these Low GWP synthetic refrigerants Natural Refrigerants such as Hydrocarbons and CO2 are also being increasingly applied which have GWP levels of 3 &1 respectively. This means that it is now not at all impractical to utilise either Natural Refrigerant or Low GWP F-Gas refrigerant and deliver a system that is not only low carbon in operation but is also low carbon in terms of the working fluid/refrigerant utilised within the Heat Pump or Chiller.

Concept Review – Design Support – System/Equipment Supply – Service/Maintenance Support

The GWP level of refrigerants is becoming much more relevant as it is now recognised that the lifetime carbon emissions of a Heat Pump or Chiller installation are directly related to the refrigerant selection within the unit. This is where best practice advice should always point towards the use of a refrigerant with sub 700 GWP regardless of the application and sub 10 GWP where practical to do so.

Alongside the increasingly important focus on carbon emissions, F-Gas legislation is also driving down the use of High Global Warming Refrigerants.

As early as 2014, a revision or sharper tightening of the F-Gas Regulation took place, with the result that HFC refrigerants with a GWP> 2500 were banned in new plants from 01.01.2020. As of 01.01.2022, this prohibition also became applicable to refrigerants with a GWP> 1500, as far as they are used in commercial refrigeration systems with an output of more than 40 kW. In order to achieve the set climate protection targets, further tightening or revisions of the F-gas regulation are to be implemented over the coming years.

In October 2023 European legislation was introduced that stipulates Chillers will be required to operate with 750 GWP and below from 2027 with commercial Heat Pumps operating with 150 GWP or 750GWP and below where necessary from 2030. Since Brexit the UK has its own F-Gas legislation which will provide the same Low GWP focus as the European legislation.

Of course, in addition to direct emissions, indirect emissions also play a key role in the environmental performance of a refrigeration system and the efficiency of a Heat Pump or Chiller is more influenced by system design than by the mere choice of refrigerant. As such Heating & Cooling plants operating with Natural or Low GWP (SUB 700) refrigerants function efficiently whilst practically addressing the need to move to lower Global Warming Potential refrigerants.

An application requirements will dictate the refrigerant options available and this will always be the design/specification driver but with the choice of plant now available it is not impractical at all to achieve a project specification to include either Natural Refrigerant or Low GWP F-Gas refrigerant and deliver a system that is not only low carbon in operation but is also low carbon in terms of the working fluid/refrigerant utilised within the Heat Pump or Chiller.

  • Refrigerant environmental impact is classified by GWP
  • Global warming potential (GWP) quantifies the impact of a refrigerant as a factor of carbon dioxide
  • GWP compares each refrigerant to an equivalent mass of C02.

Refrigerant selection is key to ensuring an application is both F-Gas future proof and also delivering the lowest carbon impact.

The illustration below shows a range of refrigerants with their respective Global Warming Potential.

Global Warming Potential Graph

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