Author Topic: DIY water chiller - reading suggestions?  (Read 3232 times)

BruceM

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Re: DIY water chiller - reading suggestions?
« Reply #180 on: September 18, 2021, 11:35:00 PM »
Ha!  Bad headache today but maybe tomorrow I'll evacuate then charge and give the Emmerson a go.

BruceM

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Re: DIY water chiller - reading suggestions?
« Reply #181 on: September 25, 2021, 11:38:05 PM »
I took out the TXV that can't be adjusted without evacuating the system, and put in a needle valve plus the cap tube.
That let me restrict flow as temperatures climb to keep a constant 4.6 amps.

I tried wood then a metal cover for the condenser coil to restrict airflow so I could simulate a hotter day. The leaky stack of lumber gave better results; the metal cover seemed to cause greatly elevated current for the same temperature. Something about too much of the coil not being cooled at all.  The metal cover is shown in the picture.

As liquid line temperature got above about 95F, the BTU perfomance starts to fall off rapidly.  I'm able to get 13.6K BTU's at 90F,  13.0K at 94F, 10K BTUs at 102F.   Then it falls on it's face, and there's no chance of it not being adjusted properly, since I was doing it manually while watching compressor current, every so slowly.

So evaporative precooling is a must; my former LG window unit doesn't have the advertised 12000 BTUs, EER of 11.3 at 95F ambient at my elevation, at least.  (95F would be 110F liquid line temp at 15F approach).  I'm not getting anywhere near this performance at 95F equivalent liquid line temps.  More like 4000 BTUs.

I can likely live with the needle valve/cap tube combo, but could get the best cooling performance with an electronic expansion valve and custom microcontroller programmed to adjust for max rated amps.  They are cheap, but no one but me could maintain it or appreciate it. 


« Last Edit: September 26, 2021, 04:03:03 PM by BruceM »

BruceM

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Re: DIY water chiller - reading suggestions?
« Reply #182 on: September 27, 2021, 12:58:33 AM »
This afternoon I picked up the bargain bigger brother of my 12K BTU LG; the 18K BTU model from a nearby seller on Craigslist.

It has a bum evaporator side blower wheel, that is making some slight noise, and was pretty dirty, thus the new bargain price of $150.  I'd been watching it for a few weeks.

I ran it before taking it apart for a good cleaning and inspection; it draws 1600 watts while running the blower on high.  The compressor sounds good and the air was cool.  The total unit and the condenser seem huge compared to my 12K unit.  The fan motor on the 18K unit  is 276W instead of only 80W for the 12K unit.  One option is to use the 12K compressor on this chassis, with it's much larger fan and condenser coil.  The fan will have extra power for the evap cooling without a supplemental fan.

The question in my mind is if I reduce the power via cap tube/needle valve combo, can I still get good BTU levels.  Even more interesting would be if I can get acceptable performance at higher temperatures without adding an evaporative pre-cooler. 

I was surprised that this unit has an LG compressor, made in Korea. 

I just couldn't resist it for $150.