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10-20-12, 03:15 PM | #1 |
Supreme EcoRenovator
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cheap window reverse cycle ac build
Hello all, this will be my first thread on the site. I've been lurking for awhile, gleaning information and experimenting in the shadows. I've noticed that lots of people are asking the same questions I am regarding details in building simple, cheap units that actually work. So I'll be asking for input from you more experienced builders to try and sort out answers while building something that works like it should. Mind you, I'm not rich... in fact, I'm usually broke. So custom data acquisition loggers / computerized controllers / postage stamp solid state phasers are pretty much beyond the scope of this build. Not that this unit won't have controls, just not complicated expensive controls.
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10-20-12, 03:58 PM | #2 |
Supreme EcoRenovator
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The unit I have chosen to modify is a vintage GE window air conditioner. It was donated to me by my wife's grandma when she upgraded to something newer. Beige box with a brown grille, 110v, 12k btu. I'll post pics of it when I have enough posts, but I bet you've all seen one. Made in USA, built to last a long time, cheap and commonly available. Not much to look at, perfect for a hot rod project.
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10-21-12, 07:49 AM | #3 |
Helper EcoRenovator
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im sure i wont be much of help, but you have my attention.
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10-21-12, 09:07 AM | #4 | |
Lex Parsimoniae
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Quote:
It was able to heat up a small bedroom. But it wasn't really very cold outdoors.. I took the rig down to my basement and setup to heat a very small laundry room. http://i46.photobucket.com/albums/f1...heatOutput.jpg Sat the unit in the doorway and blocked the top with a blanket. It was cool in the basement (60-62F) and it heated the 8'x8' room up, over 10deg F.. My guess is, a good 12,000 BTUh window AC plugged in backwards, will give you around 12,000 BTUh of heat, when outdoor temps are in the 60s (or higher). But, as the outdoor temp drops, so will the BTUhs of heating.. It will stay on longer, so it will use more power to 'pump' the same amount of BTUhs indoors. Window type ASHP heater/coolers are selling now, but 40F outdoors is their limit. (On all of the ones I've inquired about). I think you will still get some heat pumped in, but when it gets really chilly outdoors, you might do better with a $20 1500w ceramic space heater or two.. In order to make this experiment work, I had to insulate the thermostat sensor that's normally found mounted in the center outside of the indoor HX coil (Evap). If I wanted to build a control for this hack, I would place a heater resistor on the AC thermostat sensor tube (wrapped with insulating tape) and apply heat to the thermostat tube, so the cold outdoors wouldn't keep turning off the compressor.
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My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less.. Last edited by Xringer; 10-21-12 at 09:18 AM.. |
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The Following User Says Thank You to Xringer For This Useful Post: | IamIan (10-26-12) |
10-21-12, 08:11 AM | #5 |
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Sounds very interesting Jeff. I can't wait to see more.
What major modifications do you have planned in order to make this thing work efficiently as a heater?
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10-21-12, 12:46 PM | #6 |
Supreme EcoRenovator
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xringer,
I did the same thing with my other vintage window rattler! It's a 9000 btu kenmore, pretty much a clone of the one in this project. It's proving its right to live in the sunroom window as we speak. I basically just reversed the connections to the compressor (the pipes fit inside each other when spliced), brazed a service valve to the factory crimp jobbie (bullet piercing valves are ok to suck out the cfc refrigerant but that's about it), and left the rest alone. Vacuum, purge, vacuum, purge, vacuum, refill w/ propane, run. As for the control, it has a bulb thermostat which has both no/nc contacts. So now the factory thermostat heats! Thanks Sears... they must have made 25 models out of this one frame... I did have to move the sensor bulb off the coil so it cycled less often. I imagine the original model had a strip heater someplace when equipped |
10-21-12, 01:08 PM | #7 |
Supreme EcoRenovator
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well... that pic didn't post. Lemme try another way.
When I had this one running backwards, err, like it was built, the evap coil froze up pretty fast when it got down around 45-50*f outdoors. Now that it has been reversed, it goes pretty strong until it actually frosts outside. Last night, it got down to 39 at like 95%rh. The unit was weeping but didn't freeze up. |
10-21-12, 04:50 PM | #8 |
Lex Parsimoniae
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Kenmores Rule!
I have an old 18,000 BTUh Kenmore (got used for $200) and it worked pretty well.
Might be a good candidate for the old SwitcheRoo on the compressor lines. But, since we already have some good performing Sanyo mini-splits, that brazing fun isn't going to happen. http://i46.photobucket.com/albums/f1...10breakman.jpg http://i46.photobucket.com/albums/f1.../10goofing.jpg
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My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less.. Last edited by Xringer; 10-21-12 at 06:07 PM.. |
10-21-12, 11:15 PM | #9 |
Supreme EcoRenovator
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Wow, I wish I had a nice shiny new unit like that to dissect! The warranty police would be pissed! I'd have that baby heating and cooling my house, making me hot water, and putting money in the bank every month! I'd have to build a cage around it so it wouldn't get kidnapped! Nice.
Ok, so I went to the barn today and dismantled the patient. It seems it has had prior surgery.Take a look: |
10-22-12, 08:55 AM | #10 | |
Lex Parsimoniae
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Quote:
This model Sanyo has bad programing (IMHO) and my first unit lost it's R410A. If you aren't watching them closely, these things will over-load/over-pressure and pop an artery. Sanyo sent me a new outdoor unit (on warranty) and didn't want the broken one back. I was able to repair it (no warranty) and ordered a new indoor unit for it. So, it was a pretty good deal for a second 24k cooling / 36k heating system. I considered using the 'spare' for hot water too, but now that I've got the AirTap A7 ASHP hot water heater, I'm glad I didn't mess with a Sanyo. The AirTap uses very little power and I can get hot water, even when I don't need cooling or heating running.. (like today). Since I was burning oil for hotwater before, I might be at breakeven by next fall. (Depending on fuel oil prices).. Good Luck with your surgery doctor!
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My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less.. |
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