Gas / Liquid ratio in Condenser

[stesmith1981]

Does anyone know if it is possible to calculate the ratio of gas to liquid in a condenser within an air conditioning system within a military vehicle.

[frank]

I suppose the easiest way would be to use the Mollier chart.

[stesmith1981]

Just had a scan over the internet looking at the mollier chart. Not entirely sure how they work. I am using R134a for my system in an ambient temperature of 35 degree, is it possible to use such a chart for this process.

[frank]

Yes it is. It may also be known as a p/h chart.

[NoNickName]

Coolpack by NIST will help you.
It is free to download and will simulate the gas/liquid percentages upon custom coil design.

[Peter_1]

I know Coolpack from the Danish Technical University.
Is this another Coolpack package?

[NoNickName]

Sorry, I stand corrected. I meant EVAP-COND by NIST, the national institute for standards of USA

[frank]

You could also determine the liquid level in a DX evaporator using a temp probe. Measure the temps up the coil bends and note the temps. As you approach the outlet the temp will increase significantly indicating the phase change area.

All you have to do then is calculate the proportion of coil with the lower temps against the proportion with higher temps.

[US Iceman]

Franks method is very straightforward and an easy way to check.

As an estimate for an air cooled condenser (with no head pressure controls, and you will not have these on a vehicle) is to use about 85-90% of the condenser volume for the vapor volume. About 10-15% will be the liquid volume.

[frank]

I've got to ask the quesion though? - why do you want to calculate the liquid/vapour ratio?