the most efficient refrigerant

[joe magee]

What is the most efficient hfc refrigerant? The lowest gwp?

[nike123]

what is the most efficient hfc refrigerant?

r410a.............

[NoNickName]

It depends on the conditions. There is no such an answer. The lowest gwp is for R744

[Tony]

Hi NoNickName,

The lowest gwp is for R744

First, to be clear R744 in not a HFC and

Secondly if you are including R744 - R717 is the lowest (and most efficient).

[NoNickName]

R717 is not the most efficient. Is the one that carries more heat per mass, not necessarily the most efficient. That's why I asked for the conditions.

[james10]

Condition's aside, R718 has the lowest gwp.

[NoNickName]

not true, water vapour has a considerable global warming effect

[desA]

Lowest gwp should be R-728 at 78.084% / R-732 at 20.947%

[james10]

not true, water vapour has a considerable global warming effect

The official gwp is Zero, unless i am misinformed further reading on this subject would be interesting if you happen to know any good references.

[NoNickName]

The official GWP of water is unknown because it is dependent on temperature and phase. When condensed, it is opaque to sun radiation and its GWP is negative and is called albedo.
When not condensed, it is transparent to infrared radiation at high frequency (from sun) and opaque at infrared radiation at low frequency (from earth).
GWP of water is therefore undetermined, but very high at uncondensed phase.

desA got it right. Air has the least GWP.

[Quality]

Air does have the lowest GWP by numbers but water evaporated by the sun has no GWP as it "GWP" is only calculated by non natural processes - don`t try and argue as most folk do that there used to be no sun

I live around many farms with lots of cattle sure methane has a specified GWP but not from naturally produced methane

It Is measured ONLY on man made contribution

Facts are facts

regulations and the real world differ

NEXT!!!

[NoNickName]

You are taking it too seriously

[Quality]

No I am taking the facts and to be fair they are not my facts but those of the Kyoto protocol

I must stress that is a fairly light comment from yourself

[joe magee]

Yikes! sorry I asked that question.
Reason was the company I work for built it's second CO2 rack.(subcritical).
The top cycle is 134A.
Was wondering if there was a more efficient refrigerant they could have used in that application.

[Peter_1]

What is the most efficient hfc refrigerant? The lowest gwp?

R134a, lowest GWP for commercial appl.

[NoNickName]

Was wondering if there was a more efficient refrigerant they could have used in that application.

Considering a middle temperature of -10°C, yes, there is a more efficient refrigerant.

I must stress that is a fairly light comment from yourself

[Peter_1]

Yikes! sorry I asked that question.
Reason was the company I work for built it's second CO2 rack.(subcritical).
The top cycle is 134A.
Was wondering if there was a more efficient refrigerant they could have used in that application.

CO2 and NH3 is the best solution then

[coolkid]

Peter_1

R134a, lowest GWP for commercial appl.

Until of course HFO1234yf starts to be used!!

[NoNickName]

Until of course HFO1234yf starts to be used!!

Unlikely for fixed installations.

[joe magee]

Interesting. I have never seen 134A used in a Rack application or in a condensing unit. Only self contains.

[desA]

desA got it right. Air has the least GWP.

Thanks for that. Smart fellow, you are.