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Thread: discharge superheat????????
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07-07-2010, 07:13 PM #1
discharge superheat????????
hi guys we had a techie from a "certain" manufacture come to our site the other day to look over a DX condenser, he did the usual Superheat + sub cool ect, but he also checked discharge superheat ?
not sure how he worked it out or why? what help is this in diagnosing a system and how did he work it out? discharge temp against what saturation temp?????, its new to me?
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07-07-2010, 08:36 PM #2
Re: discharge superheat????????
The discharge superheat is calculated the same way as any other superheat/ subcool on a system. By measuring the discharge superheat you can subtract the suction superheat and that then leaves you with a figure of how much superheat the compressor has given through compression and mechanical /electrical inefficiencies.
So if you have the operational envelope data for the compressor you can use the reading to diagnose faults that may not be apparent through other means.Quidvis Recte Factum Quamvis Humile Praeclarum.
Latine dictum, sit altum videtur.
Si hoc comprehendere potes, gratias age magistro Latinae.
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07-07-2010, 09:21 PM #3
Re: discharge superheat????????
Discharge superheat gives you an idea of what's happening inside the compressor.
Checking also this way for non-condensables or a cross check or security check for other measurements.It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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07-07-2010, 09:21 PM #4
Re: discharge superheat????????
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07-07-2010, 09:32 PM #5
Re: discharge superheat????????
Hi SyWalker, to measure discharge superheat,
1)take the discharge pressure and convert to temp using comparator then
2) take the discharge temperature
subtract 1 from 2 and that will gve you your discharge superheat.The difference between genius and stupidity is that genius has its limits.
Marc
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07-07-2010, 09:49 PM #6
Re: discharge superheat????????
The discharge superheat is usually the total super heat of the system or more accurately the superheat reading taken at the place when no more energy is gained or lost.
This is still measured as refrigerant temp - saturated condensing temp for the measured pressure (all measured from same test point) this can be subtracted from (or added to) and shows enthalpy gains or losses to the refrigerant caused by the system.
The above assumes that the system is balanced and mass flow is steady at the times of readings.
I hope that explains it.
So Yes you can add and subtract superheat readings if the system is balanced.
And No we wouldn't take discharge temp. and subtract suction superheat.Quidvis Recte Factum Quamvis Humile Praeclarum.
Latine dictum, sit altum videtur.
Si hoc comprehendere potes, gratias age magistro Latinae.
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08-07-2010, 08:40 PM #7
Re: discharge superheat????????
thanks Marc and trash, trash your answer is a bit on the technical side but I understand the basics of what your saying, I presume you have studied refrigeration at university?
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08-07-2010, 10:33 PM #8
Re: discharge superheat????????
trash your answer is a bit on the technical side but I understand the basics of what your saying, I presume you have studied refrigeration at university?
CheersQuidvis Recte Factum Quamvis Humile Praeclarum.
Latine dictum, sit altum videtur.
Si hoc comprehendere potes, gratias age magistro Latinae.
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11-07-2010, 07:25 AM #9
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11-07-2010, 07:28 AM #10
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11-07-2010, 08:02 AM #11
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Re: discharge superheat????????
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11-07-2010, 08:59 PM #12
Re: discharge superheat????????
its good comment Nike, just wondered on the first link were the picture has gone?(LOL)
Ice
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