HFC 134a

[barathrao]

Hi all

Recently I read that R134a has more capcity to absorb water than traditional !! around 20-25 times than R 12 at 32 F temperature!! Because of which the moisture levels might go to dangerous levels!!
What could be the effects of these higher moisture levels!! (other than corrosion)?

Could anyone enlighten me!!

Barath.

[Brian_UK]

The higher moisture levels can cause several problems one of which is that the moisture will freeze creating a blockage at any small orifice within the system; generally the flow regulating expansion device. This of course will stop the refrigerating effect.

Other problems are the contamination of the lubricating oil which forms acids within the system. These then attack the motor windings of the compressor and destroy the motor.

As you can see the LAST thing a refrigeration system wants is moisture.

Good luck with your Masters

[superheat]

If the ***** absorbs miosture, it is less of a problem. The easier it absorbs miosture, the harder it holds the miosture. What you have to worry about is the interior dew piont. When the ***** temp drops to the dew piont, water starts to condense out of the *****. Free water is the problem. No matter what type of ***** you are using, you must maintain a dewpiont at least 10 degrees below the lowest possible temp in the system.
Now the POE oil might be a different story. It is possible for the oil to draw miosture out of the *****. POE oil has a high affinity for miosture. If the oil has a higher affinity than the ***** you have a problem.
Is this part of your master's thesis?

[barathrao]

Thanks for the insightful information!!

My masters thesis is on Thermodynamic modeling of mixtures containing hydrogen fluoride..its hard core chemical engineering thesis.. I was working on predicting and correlating the phase equlibrium properties of binary mixtures containing HF,the second component will be like R12, R113, R134a ,water, propane etc..which are used in refrigerant or foam blwing agent industries
I was dealing with immisciblity of mixtures ...rather phase instablity!!! formation of two phases of liquid!! I wanted to know more abt how it goes industrially...btw I graduated a cpl of months before and looking for job opportunities!!! What are u working on ?

[Prof Sporlan]

Recently I read that R134a has more capcity to absorb water than traditional !! around 20-25 times than R 12 at 32 F temperature!!

This is true in the liquid phase of R-134a. This type of data is available in chapter 6 of the ASHRAE Refrigeration Handbook.

[abcdefg1675]

How much does R-134a cost per pound? ive seen in a few catalougs that use have these things that you can blast dust out of things, or use to to cool things by spraying it. the can contains 3lbs of R-134a and it was ~16$ for the thing (this book is a few years old)

[superheat]

The refrigerants ability to hold water is not that important to a service tech. The important parameter is the dew point. This is relative humidity not absolute humidity.