Calculating pressure drop for metering device

[knkreb]

Going to be doing a heat pump experiment in basement with some used parts/compressors, etc.... Thinking of using 3/16" tubing as the metering device... but I can't find any kind of calculators, formulas, etc online to compute with a given head pressure and suction etc, to get how long of a piece of tubing do I need to get x-amount of pressure drop....

Thoughts anyone?

[Tesla]

Start with calculating refrigerant flow rate required, then friction of 3/16 per metre, use a formulae to convert to pressure drop. Or you could just use a cappillary tube and ring tube manufacturer for rattings/usually provided on ctube packet in a table.

[nike123]

Why are you fixed at 3/16" tubing?
Capillary tubes are cheap and easily available.

[knkreb]

I have some 3/16" right now... the thing I'm not real crazy about with cap tubes is that they clog. With a larger diameter tubing, it would be less apt to clog... I heard of a story that years ago Lennox used such a method for their systems...

Tesla, thanks for the direction... any idea what the friction of 3/16 tubing is?

[Toosh]

I have some 3/16" right now... the thing I'm not real crazy about with cap tubes is that they clog. With a larger diameter tubing, it would be less apt to clog... I heard of a story that years ago Lennox used such a method for their systems...

Tesla, thanks for the direction... any idea what the friction of 3/16 tubing is?

Hi Kn, Have a look at this there is a free download

http://www.pipeflow.co.uk/public/control.php?gclid=CPSthIr3jpgCFY0wpAodtme74Q

Regards Norm

[jose regueiro]

You have DIRECTCALC from DANFOSS
xxx://xxx.danfoss.com/BusinessAreas/RefrigerationAndAirConditioning/Product+Selection+Tools+Details/DIRcalc.htm
or
coolpack