How Much Gas?

[walden]

I am not a refrigeration engineer. I design and build the electrical control panels which sit next to the compressor packs in the plant room. One thing has always fascinated me. How do you know how much gas to buy in for a system? Do you add up the volume of the evaporators, condenser, pipe-work? And, how do you know when the system is full or full enough?

[Josip]

Hi, walden :)

By simple and sometime bored calculation of volume if you have complete info about lenght and diameter of pipes, evaporator...:)

Of coures all equipment must be sized before installation:D

Or you just add some quantity and then start up machinery checking superheat on suction. Systems with refrigerant receiver you can just fill up to 3/4 (25% gas phase) or 4/5 (20% gas phase this one is better becuse you can charge more gas :) ;) ) of receiver volume what must be enough, if not than add some more checking system again;)

When you have design papers then you have that figure, if not, than you must some have experience.

Finally you can do it by trying/missing (there must be some other expresion in english but I do not know, sorry;) )

Believe that other guys will say something more...

Best regards, Josip :)

[slingblade]

At the design stage a total charge of gas for a plant will be calculated. on site an engineer most of the time will find a plate on the machine with a charge in weight, scales can be used to charge exactly. if a system does not have this or is partly full following a leak for example, then we use pressure gauges to view and asses system performance and charge as necessary.



Finally you can do it by trying/missing (there must be some other expresion in english but I do not know, sorry )



Trial and error?

try a google search for babelfish, a language translation site and see what your expression gives directly for english.;)

[Josip]

Hi, slingblade :)





Trial and error?

try a google search for babelfish, a language translation site and see what your expression gives directly for english.;)

You must be jokeing :) I try and I miss with babefish:confused:

Found this in Merriam-Webster's Collegiate Dictionary

try•ing \"tri-ing\ adjective (1718)
: severely straining the powers of endurance
try•ing•ly \-ing-le\ adverb


1try \"tri\ verb tried try•ing [ME trien, fr. AF trier, fr. OF, to pick out, sift, prob. fr. LL tritare to grind, freq. of L terere to rub — more at throw] (14c)
verb transitive
1 a : to examine or investigate judicially
b (1) : to conduct the trial of
(2) : to participate as counsel in the judicial examination of
2 a : to put to test or trial <try one's luck> — often used with out
b : to subject to something (as undue strain or excessive hardship or provocation) that tests the powers of endurance
c : demonstrate, prove
3 a obs : purify, refine
b : to melt down and procure in a pure state : render <try out whale oil from blubber>
4 : to fit or finish with accuracy
5 : to make an attempt at — often used with an infinitive
verb intransitive
: to make an attempt syn see afflict, attempt
try one's hand : to attempt something for the first time

miss•ing \"mi-sing\ adjective (ca. 1530)
: absent; also : lost <missing in action>

Yes, word MISS is much better but....

Anyhow you get my point :) ;)

If you want to help me it is much better to explain that in plain english instead to push me around to look for translations. :D

Best regards, Josip :)

[xavierdomine]

Hi, walden :)

By simple and sometime bored calculation of volume if you have complete info about lenght and diameter of pipes, evaporator...:)

Of coures all equipment must be sized before installation:D

Or you just add some quantity and then start up machinery checking superheat on suction. Systems with refrigerant receiver you can just fill up to 3/4 (25% gas phase) or 4/5 (20% gas phase this one is better becuse you can charge more gas :) ;) ) of receiver volume what must be enough, if not than add some more checking system again;)

When you have design papers then you have that figure, if not, than you must some have experience.

Finally you can do it by trying/missing (there must be some other expresion in english but I do not know, sorry;) )

Believe that other guys will say something more...

Best regards, Josip :)

trying/missing in english. trial and error!