different refrigerants, Why?

[Das71]

Can someone please explain to me the reason we use different refrigerants in diffent applications? What makes a refrigerant suitable for some applications and not others.

[Sturt]

Pressures and temperatures.

[desA]

Das71,

The use of a particular refrigerant will depend on a number of things, for the application at hand - some being:

- Latent heat [kJ/kg] (energy transport);
- Critical temperature (top of vapour bell);
- Working pressures (low/medium/high);
- Environmental impact;
- Cost;
- Availability
- Toxicity
- Fitness for purpose

[taz24]

Can someone please explain to me the reason we use different refrigerants in diffent applications? What makes a refrigerant suitable for some applications and not others.

20 years ago there were 4 refrigerants

there was

R502
R22
R12
and
Ammonia. R717

Forget ammonia for the moment because that is as popular as ever.

The other three easily fell into 3 temp brackets

R502 was about -25 degC
R12 was about 0 degC
R22 was about +20 degC

This is a very general statement because the refrigerants would cross over into other temp bands
but it makes it easy to explain.

So three refrigerants and three temp brackets.

Then the powers to be found that those refrigerants were damaging the ozone layer, so they were banned and others were brought in to replace them.

Now there are many many refrigerants on the market because there are many many producers selling refrigerant. As a new product was developed and marketed it was competeing against other refigerants and the companies producing them were selling them as the best thing since sliced bread.

Some worked with mineral oil and some with synthetic.
Some were ozone friendly and some are global warming friendly.
Some work well at low temp and some work well at high temp.

Its like comparing car manufacturers. They all produce cars but they each claim that there car is better than the competitions car.

Market forces you see.

Bring back 502, 12 and 22 I say

Chhers taz.

[Quality]

20 years ago there were 4 refrigerants

there was

R502
R22
R12

Chhers taz.

Sorry to quote you Taz but you did forget the very best R500

But yes life was easier back in the day

[lowcool]

not a bad gas either quality well done i keep forgetting this too,the good old days when you could spot a ****tail (a roosters rear end then) or otherwise known as a mixture of different refrigerants a mile away.good grief censoring to the max i feel a state of lubricity coming on.
cheers...

[taz24]

Sorry to quote you Taz but you did forget the very best R500

But yes life was easier back in the day

Yes R500.

But it is an azeotropic blend that is mostly R12

Bring em back I say bring em back.

taz.

[frank]

good grief censoring to the max i feel a state of lubricity coming on.
cheers...

Not something personal of course

just the software doing it's job.

[US Iceman]

The earlier refrigerants (except for ammonia) were an attempt to create a unique refrigerant for specific applications like Taz said. R502 was used for low temp systems because it had a low specific heat ratio. That translates into low discharge temperatures at high compression ratios.

R12 and R134a have been around almost as long as each other. They were developed sometime around WWII. R22 was attempt to get more capacity our of the refrigerant, while R12 was a decent low pressure refrigerant for many applications.

All of these new refrigerants are a way to make money as the patents went out of date on the old stuff. Global warming and greenhouse gases is how they sold it.

[Darren Cassin]

Thanks Iceman this sounds like the sort of info I am after. I guess to be more specific and simplify the question using the original refrigerants as an example what specifically made R12 more suitable to its medium temp (cool room) applications than R22? I realise that today’s refrigerants are so varied due to corporate, economic and environmental factors but I am after a more technical or scientific explanation as to why we didn’t use say, R22 for example, for everything back when the major factor influencing refrigerant choice was based on what worked best.

[subramanyam]

refrigrant is selected based on their thermodynamic properties, and the temp you would like to acheive, availability, cost, environmental impact etc

[subramanyam]

The earlier refrigerants (except for ammonia) were an attempt to create a unique refrigerant for specific applications like Taz said. R502 was used for low temp systems because it had a low specific heat ratio. That translates into low discharge temperatures at high compression ratios.

R12 and R134a have been around almost as long as each other. They were developed sometime around WWII. R22 was attempt to get more capacity our of the refrigerant, while R12 was a decent low pressure refrigerant for many applications.

All of these new refrigerants are a way to make money as the patents went out of date on the old stuff. Global warming and greenhouse gases is how they sold it.

Dear Ice Man,
Does the refrigerant has any impact interms of heat transfer