The requirement for refrigerants that very quickly dissipate

anon_ymous

This is a fairly old article but realistically the points still stand

https://theecologist.org/2010/oct/08/why-eco-friendly-heat-pumps-increase-not-reduce-your-carbon-footprint

Heat pumps are touted as the more environmentally friendly alternative to gas or to condenser tumble dryers 

The biggy however, like with AC, is the refrigerant. Realistically the refrigerant WILL eventually leak so the issue is mostly regarding how long it stays in the atmosphere after leaking. If the gas stays in the atmosphere for just a few days, we're golden. If even a few years we're not so golden given that the GWP of these refrigerants are often several times higher than fossil fuels 

QrizB

waqasahmed said:

If the gas stays in the atmosphere for just a few days, we're golden. If even a few years we're not so golden given that the GWP of these refrigerants are often several times higher than fossil fuels 

That article was somewhat alarmist, even in in 2010.

It states:

However, both of these regulations omit the inconvenient truth that heat pumps use, and emit, hydrofluorocarbon (HFC) gases that are as much as 2,000 times more potent in heating the atmosphere than garden variety carbon dioxide.

The Kigali Amendment to the Montraql Protocol has seen R-410A phased out and replaced, mainly with R-32. Most heat pumps installed in the recent years have used R-32 (eg. Mitsubishi Ecodan, Daikin Altherma).

And that's still transitional; longer term, it seems likely that R-744 (carbon dioxide, GWP=1) will replace R-32 in relatively short order. See for example the Ecodan QUHZ.

QrizB

Replying to myself is an awful habit, but I wanted to add that this typical Mitsubishi Ecodan heat pump contains 2.2kg of R-32 with CO2 equivalence of 1490kg of CO2. That's roughly the amount of CO2 released by burning 7500kWh of natural gas; less than one year's heat demand for a typical UK home.

DougMLancs

A lot of manufacturers rolling out R290 (propane) in their new domestic units this year too which has a GWP of just 3.

Grandad2b

R600a (iso-butane) has a similar GWP of just 3.3. I was pleasantly surprised to find it's in the fridge freezer we inherited from my late mother in law 8 years ago.

QrizB

R-290 and R-600a are good for small systems (fridges, freezers single room splits) but flammability is a concern with large ones.

anon_ymous

QrizB said:

R-290 and R-600a are good for small systems (fridges, freezers single room splits) but flammability is a concern with large ones.

What are they using for larger appliances? 

anon_ymous

QrizB said:

waqasahmed said:

If the gas stays in the atmosphere for just a few days, we're golden. If even a few years we're not so golden given that the GWP of these refrigerants are often several times higher than fossil fuels 

That article was somewhat alarmist, even in in 2010.

It states:

However, both of these regulations omit the inconvenient truth that heat pumps use, and emit, hydrofluorocarbon (HFC) gases that are as much as 2,000 times more potent in heating the atmosphere than garden variety carbon dioxide.

The Kigali Amendment to the Montraql Protocol has seen R-410A phased out and replaced, mainly with R-32. Most heat pumps installed in the recent years have used R-32 (eg. Mitsubishi Ecodan, Daikin Altherma).

And that's still transitional; longer term, it seems likely that R-744 (carbon dioxide, GWP=1) will replace R-32 in relatively short order. See for example the Ecodan QUHZ.

I did notice that we we moving to CO2 based refrigerants tbf.

Could we have something that has a GWP of else than 1 too?