PDA

View Full Version : Using Old Fridge compressor with LPG







Simeon
15-07-2014, 11:23 AM
Im making a little project at home and i would like to use LPG with an old sealed black dome compressor from a small fridge ?

Just checking is that any sparks or anything inside these sealed comps is it safe to charge the system up with lpg .

Brian_UK
15-07-2014, 11:27 AM
As long as you have evacuated the system properly then there won't be an air/gas mixture to catch fire.

Ensure that your external electrics are safe also.

Simeon
15-07-2014, 11:37 AM
Yes remove all the oxygen then it cant burn . Got it . I was using 134a but annoying reclaiming everytime i wanted to add or remove something on the system .

I have found the regulator on the lpg bottle to be set to low so going to use the compressor to suck in the gas .

Brian_UK
15-07-2014, 10:31 PM
Haven't done it myself but I believe BBQ gas is poor quality for refrigeration but would be pleased to be proved wrong.

Would have thought that the vacuum should pull in the charge.

frank
16-07-2014, 08:49 AM
Would have thought that the vacuum should pull in the charge.
Or the higher pressure from the cylinder ;)

frank
16-07-2014, 08:50 AM
I have found the regulator on the lpg bottle to be set to low so going to use the compressor to suck in the gas .
How are you measuring your charge?

xxargs
16-07-2014, 05:51 PM
LPG/BBQ-gas is very different in different country, in scandinavia I live, is always >95% propane and other part in blend is mostly butane (blend of isopbutane and n-butane) and if pass filter dryer some turn (drying and take away some of ethymercaptane as odor agent) is not so bad at home made replacement of R290 and almost fit specifikation for R290 in Danfoss litterature (little to high part of butane-blend compare to specification, but in this case is not a problem).

So, first check yor blend in your BBQ/LPG pressure and temperature compare to HC blend chart and calculate butane part in your blend is a 2/3-part N-butane and 1/3-part is Isobutane...

Or buy small package with know inside content and blend itself if you want for example 60% propane and 40% isobutane for replace R134a (but this blend have not so small glide) or buy already blended comercial kit at envirosafe/duracool (still big glide)

Is hard to find low glide blend or single non HCF-refrigerant to replace R134a - closest match single component refrigerant i know so far is DME (Dimethylether) with exellent termodynamic properties close to R600a in term of theroetic COP, flamability LEL is 50% higher (~3%) than propane/butane in air (2%) and close to R134a/R12 pressure range!!, but problem is to get it in pure form and need check how works with oil in compressor (i think solve (to?) easy in POE-oil but hard to solve in mineral oil) and wearing and tear over long time running etc.

The MG Pony
20-07-2014, 02:06 AM
bbq grade R-290 works fine, just dry it good let it run for a good while then dump and replace the oil, the oil will take most the contaminants out with it leaving you pretty clean gas.

for a small air con of my own I even used it to recharge, it lasted a good long time and drew much less power then on r22.

Naturaly be very cuatious to ensure all things are sound on the compressor and the coils.