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kingc66l
24-09-2012, 05:46 AM
Hey all,

NZ first year apprentise question ..

In what way would use a Zeotropic from an Azeotropic refrigerant ?

Teuria
24-09-2012, 03:07 PM
Hi

Azeotrope
- A mixture made up of two or more refrigerants with similar boiling
points that act as a single fluid. The components of azeotropic mixtures will
not separate under normal operating conditions and can be charged as a vapor or
liquid.

Zeotrope - A mixture made up of two or more
refrigerants with different boiling points. Zeotropic mixtures are similar to
near-azeotropic mixtures with the exception of having a temperature glide
greater than 10° F. Zeotropic mixtures should be charged in the liquid
state.

from http://www.refrigerants.com/terminology.htm

Hopefully this was what you asked.

kingc66l
25-09-2012, 12:49 AM
Thanks Teuria,

WOULD azeotrope refrigerants that can be charge vapour or liquid and must have better stability to act as a single fluid , be better than a zeotropic which has differing boilings points can only be charged by liquid ( what about when system has leak this alters the component % mix.

If azeotrope is better why dont we use more R507 here in NZ instead of R 404A.


If it is not why is zeotrope better ??

mad fridgie
25-09-2012, 02:14 AM
Thanks Teuria,

WOULD azeotrope refrigerants that can be charge vapour or liquid and must have better stability to act as a single fluid , be better than a zeotropic which has differing boilings points can only be charged by liquid ( what about when system has leak this alters the component % mix.

If azeotrope is better why dont we use more R507 here in NZ instead of R 404A.


If it is not why is zeotrope better ??

R507/R404a, is more to do with patents and commercial politics than engineering.

If you look at engineer data, these 2 refrigerants are normally placed together.

However that is not to say that there is not a slight difference.

kingc66l
25-09-2012, 04:57 AM
Hi mad fridgie

134a the slight difference.. how would you answer the below question my friend?


so the question they are asking ( which I think doesn't make sense)

" in what way would use a zeotropic from an azeotropic refrigerant?"

mad fridgie
25-09-2012, 06:36 AM
Hi mad fridgie

134a the slight difference.. how would you answer the below question my friend?


so the question they are asking ( which I think doesn't make sense)

" in what way would use a zeotropic from an azeotropic refrigerant?"

R134a, is not a mixture, as the other 2 are.

I think the question is based upon charging, so Zeotropic liquid charging only!

Rob White
25-09-2012, 05:35 PM
.

One of the components of 404 is 134a, 507 does not have 134a inside.

As for why you would use one over the other.

Azotropes have no or negligible glide so will not seperate out.

At 2 bar the enthalpy for both is very similar so no real energy
advantage for either of them.

Zeotropes should be charged in liquid form to prevent seperation.

The only one advantage of a zeotrope over the azeotrope is in water
chillers. The glide during the evap process actualy gives a better transfer
of heat.

So for all normal aplications I don't know of any real advantage except
in water chillers.

Regards

Rob

.

kingc66l
27-09-2012, 07:58 AM
cheers guys

thanks for input