Avoiding Killer Chemical Refrigerants In Heat Pumps

A recent LinkedIn post of ours generated a lot of interesting discussion. The subject was killer chemical refrigerants, and why they currently dominate the market.

So we thought we’d do a post about what killer chemical refrigerants are, why they’re currently popular, and what the preferred alternatives should be.

What are killer chemical refrigerants?

When we discuss killer chemical refrigerants, we generally mean HFO (hydrofluoro-olefins) & HFC (hydrofluorocarbons). They are the most widely used refrigerants in heat pump installs right now – because they’re relatively easy to work with, and have a long history in cooling where they perform well. .

But, if you’re installing a heat pump as part of a green initiative, they present massive problems.

If we were to install 600,000 heat pumps per year (which is the Government’s target) using HFO or HFC refrigerants, it could generate the same emissions as running a 500KW boiler flat out continuously for 656 years.

We’ve run the numbers. Of course, there would be differences in practice depending on specific refrigerants used and their size, but the legacy of installing HFO and HFC heat pumps is terrifying:

Assuming 600,000 quantity of heat pumps per year:

1774 GWP of typical refrigerant r407c
5.5 kg – typical charge
10% unintentional loss of refrigerant in use or in recovery
585,420,000 equivalent emissions kg of CO2 from lost refrigerant
0.20374 Fossil gas Kg CO2 /KWh

Plus, any company that installs one of these heat pumps would have to add to their carbon footprint. As part of an organisation’s carbon footprint disclosure it must account for all F-gas fugitive emissions. That is the quantity of HFC, HFO and HC lost from their systems each year due to leaks or service work. High-GWP working fluids will result in a higher disclosure, affecting organisational carbon reduction plans and public disclosure.

What’s more, F-gas regulations have been steadily reducing the quantity of high GWP gasses available and some of the worst are now completely banned. This trend is expected to continue in order to reduce the impact on the environment, currently F-gases are 3% of global emissions. Not only are they being regulated out but there have been significant price rises, in some cases by over 300 %, as supplies become restricted.

So by installing a killer chemical refrigerant heat pump, you’re storing up problems for yourself and the plant down the line.

What Heat Pump Refrigerants Should We Be Using Instead?

The best approach would be to use natural refrigerants, of which propane and CO2 are the most common.

Natural refrigerants:

-Perform well, better in many cases
-Are cheaper to buy
-Have low global warming impact

Using CO2 As A Natural Refrigerant For Heat Pumps

CO2’s thermodynamic properties, and low GWP, make it an ideal natural refrigerant of choice. It’s high performing, safe, and the total cost of ownership of a CO2 heat pump is low. We’ve written about the case for using CO2 in heat pumps here in detail.

Using Propane As A Natural Refrigerant For Heat Pumps

Propane, in terms of performance when used in a heat pump, is similar to CO2 in many ways. The largest difference is that it is flammable – but safety procedures and good engineering mean it is exceptionally safe to use as a refrigerant. Read here about why propane is a good option for a heat pump refrigerant.