Best refrigerator..R404a or R507a

[AndrOvr]

What would u pick for a R134a based compressor - danfoss NL11F for the lowest temp possible w a heat load around 180w.

[Gary]

Helium.

[herefishy]

ROFLMAO !!!!!!!!

[AndrOvr]

Originally posted by Gary
Helium.

LOL!
Ok.. seriusly.. what's the best, r404a or r507a?

[herefishy]

Hi AndrOvr,

I presume you're voiding the warranty on your Prommie. I have good experiences with putting R-404A 'em. Never tried R-507A.

[AndrOvr]

R404a as a boiling point of -46.6c and R507a as -47.1 I think... Now, as far as thermal conductivity, dont know whitch one is the best :P

[DaBit]

According to a AC/R engineer who has tried both in a Prommie, R507 gives you slightly lower temps than R404a.

[superheat]

Long time ago, I put 502 into a R12 compressor. It did not last the night.

They must be making those 134a compressors tough these days.

[AndrOvr]

R22 in a r12 compressor... it will last?
LOL
or the compressor will fail?

[Gary]

When you put a high pressure refrigerant in a compressor that is designed for low pressure refrigerant, you take your chances. Maybe it will last, and maybe it won't.

[ice_cool]

R404a is more commonly used. so it is better in most cases.

[camerond]

I've used both R404A and R507A and have done a bit of reading up on them in the past since they're of such similar composition. From what i've heard some company just wanted a piece of the money that R507A sales was making, so they added a little R134a to the mix to get around the copyright. R507A performs better though and it has been tested and proven that you can even put R507A into a R404A system without any problems. R507A also has the advantage of being an azeotrophic blend. In my opinion R507A is better, but at the end of the day it's still just my opinion. I do however use R404A for things like ice machines so the charge can still be weighed in.

[PVA]

...R507A also has the advantage of being an azeotrophic blend...

Azeotrophic.
I agry with camerond.

Ok, at first some information about tehnical data:
R404a - near azeotropic blend of of 52 wt.% R-143a, 44 wt.% R-125, and 4 wt.% R-134a.
R507a - azeotropic blend of of 50 wt.% R-143a and 50 wt.% R-125.
Azeotropes are mixture of two or more liquids in which the liquid and vapor have the same composition at equilibrium and display mono-substance behaviour at various temperatures and concentrations. In non-azeotropic mixture the vapour is rich in the lower-boiling or more volatile component.

So, the boiling point of the R507 blend components R125 and R134 are very close to each other and the vapour pressure curves are similar. Therefor, no significant composition shift are observed for R507 during use and handling. The effect of composition shift after a leak of the blend R404a followed by balancing the leak with original R404a will be small. For this near-azeotropic blend the temperature glide is small (0.6 K). The impact of such a composition shift on the performance of the installation will be negligible.

In practice, if a leak is more than 20-30% you will have to completely change all refrigarant R404a, but if you have R507a - you can only fill up the missing volume.

Price.
The price of R507a is more expensive than the price of R404a.