Overclock.net banner

1 - 3 of 3 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
Hi all,
For the last 6 years, I've had most my computers cooled using portable ac units since I found water/phase/ and tecs to much of a pain in the arse.

Your number one concern is humidity when using this setup. Make sure you have a reliable Dew point meter and one dual type j/k/e thermocouple attached to pcbs of mobo and gfx cool spots.

I basicaly took the intake thermistor out of the rear of my ac unit and placed it inside my case. I then ducted my case so that the air is close looped thru it. Now there is less air volume which needs to be constantly dehumidified as it passes over the evaparator.

I run an older i7 965EE at 4ghz with 2x 480gtx at 851/4050hmz
My avg idle humidity is 46% ; but while the ac unit cycles on and off, the humidity can reach up to 60-70% with out any issues.
Under load my cpu/and chipsets never exceed 50-60C and my gpus never exceed 65C ( fan @ 90%)

Im using a 1400 btu ac unit which is full evap and can remove 101 pints of moisture. Ive set it to 23C and never messed with that since I dont have all my pcbs conformal coated yet.

Its a crude but effective simple solution comparable to wc if you take some precations.

1. Set a max temp in the bios for the pc to auto shut off incase you forget to start the ac unit in atleast fan mode.

2. Keep an eye on the dew point meter/ thermocouple readings during the first few ac cycles as humidity is removed from ambient air.

3. You could protect against humidity by conformal coating your pcbs with an aresol and check its coverage with a black light. And put dielectric grease on all connectors/sockets.

Any one tried the portable ac in a closed loop setup?
 

·
Registered
Joined
·
154 Posts
Hello there hellisloose, Welcome to OCN!

Nice info and results... thanks for sharing your experience with us. It's good to see others using this type of cooling. Case a/c is really sweet as you can greatly exceed wc performance without all the cost. You can even operate close to 0c if setup properly. Of course the power consumption can be an issue if you run it 24/7.

I have a small 5k btu window unit with a couple 6" x 12ft flex ducts taped on with foil tape. I jumpered the thermostat to allow for constant run. That way there are no temp spikes to cause instability. More importantly, that allows the unit to provide a constant positive pressure of cool air inside the pc case to prevent condensation. I use mine mainly during benching or gaming to cool the mobo and gpu's. I usually have cascade, ss phase or chiller on the cpu's.

These a/c's will drop temps well below 0c in closed loop with constant run. The problem with that is the evap will eventually ice up.. well unless in an airtight chillbox, that's a whole other topic. I just run the flex ducts to whatever I'm cooling with no return. That provides a constant 9c air on low speed and dehumidifies the whole room. I have the unit sitting on a beer cooler and it drains right into it. I've never had any issues with condensation.

What's happening with your unit is that the moisture never fully drains from the evap fins and condensate pan. It just keeps getting evaporated back into the air when the compressor cycles off. An air temp of 23c @ 60-70%rh has a dew point of approx 16-18c. Humid but plenty safe for that temp range.

Sounds like you have everything setup very nicely for the most efficient and safe use. Not sure if you can avoid that small amount of moisture with the compressor cycling. If you could reduce that moisture then you could operate at a lower temp. You might be able to mod the condensate system to allow that to drain better. Not sure if your unit has a condensate pump or drain or both. Maybe lower the float switch or add a drain with a trap in the bottom of the pan.

I hope you don't mind but I have some questions.

1) What is the temp differential setting on the t-stat? If you have it set to cycle off at 23c.. what temp does it kick back in at with no or low load? Is there a time delay and if so how much delay?

2) When the compressor cycles off with the pc under full load, does the temp exceed the temp differential? If so by how much and how quickly?

I'd be very interested in seeing some pics of your setup.

Regards,
Drew
 

·
Registered
Joined
·
2 Posts
Discussion Starter · #3 ·
Quote:
Originally Posted by Drewmeister;15210020
I hope you don't mind but I have some questions.

1) What is the temp differential setting on the t-stat? If you have it set to cycle off at 23c.. what temp does it kick back in at with no or low load? Is there a time delay and if so how much delay?

2) When the compressor cycles off with the pc under full load, does the temp exceed the temp differential? If so by how much and how quickly?

I'd be very interested in seeing some pics of your setup.

Regards,
Drew
I'm currently away and will have to verify question 1 and 2. I wish I had a DAQ book to log all the data in real time. Ill be home for a week on the 25th. At that time I'll see if i can find a program to dump tab delimited or coma seprated data so I can plot it vs time in excel for you with loads and no loads.
I bought a crappy non data logging type K thermometer and dew point meter. Ill see if there is a cheap one for logging temp/humidity data.

My ac unit exhaust hose is about 20 feet long 8" Dia. It may be recondensating back to the unit since there is a 6ft vertical run on the back of the unit. I'll take your advice for using the rear drain after I elevate the unit off the floor a bit. I may need to also check the blowers head pressure and vent some off externaly to my closed loop. Sometimes the foil tap blows off lol. But my setup was quick and dirty. Ill also take a few pics once my setup is proper.
 
1 - 3 of 3 Posts
Top