DIY super efficient fridge.

[GasSavers_Brock]

You can still get them, they are pretty common in large boats. You can get them seperate or sort of pre assembled with a "cooling plate" you just mount inside a box of your choise. As Jim said if you can move the comperssor side outside or cool it with outside air it makes it much more effecient.

Last winter I had our chest freezer in our garage becasue of construction in the pantry area. It used 9.5kw for an entire month! In summer it uses about 1kw a day. I tried and tried to convince my wife to leave it out there, but no go

[WisJim]

A potential problem with having a refrigerator or freezer in an unheated space is that the oil in the compressor may get cold and stiff, causing the motor/compressor unit to wear out quicker than it would if the unit was in a heated space. Commercial equipment often has a compressor crankcase heater to prevent this problem. Older equipment seems to take cold temps better, but uses more energy when operating.

[GasSavers_Ryland]

SunFrost's web page has a great little write up on how their passive refridgerator assist works, when I talked to the owner of the compeny last, he said that the design worked really well, and that there is no reason that it couldn't be done, it's just a single tube filled with refridgerent, and a heat sink on either end of it, all you need to do then is drill a 1/2" hole thru your fridge, and a simaler 1/2" hole thru your house wall, maybe make it larger if you want to insulate around the heat pipe.

[GasSavers_DaX]

Originally Posted by Ryland

SunFrost's web page has a great little write up on how their passive refridgerator assist works, when I talked to the owner of the compeny last, he said that the design worked really well, and that there is no reason that it couldn't be done, it's just a single tube filled with refridgerent, and a heat sink on either end of it, all you need to do then is drill a 1/2" hole thru your fridge, and a simaler 1/2" hole thru your house wall, maybe make it larger if you want to insulate around the heat pipe.

I read the Wikipedia article on the heat pipe...neat stuff. This wouldn't work year round though, would it? You'd need some way to deactivate it, correct?

[GasSavers_Ryland]

you are correct that it wouldn't work year round, unless it got cold enough at night, but no, you wouldn't have to deactivate it if you had just a simple heat pipe tha relies on gravity to move the refridgerent back to the end that is trying to be cooled, some of the fancy heat pipes have what is almost a wick, so your refridgerent can move up hill, but if you just have a slight slope so your refridgerent can drip back to the bottom to be boiled, and start the cycle again, then it should work fine, and just cool your fridge when it's colder out side then it is in your fridge, and with a device like this insted of doing something like putting your fridge next to an outdoor wall, and cutting a large hole in the wall, you just drill a small hole, and run this tube thru, adjust the presure and refridgerant so that it will evaporate and cool down to 34 degrees, or whatever, then as long as it's cooler outside then it is in the fridge, the cycle will start.

[GasSavers_Randy]

I went ahead and tried this. I built a thermostat, mostly out of surplus parts I had sitting around. It's an all-analog design, similar to the one in the first article, and it was just intended to be a one-off thing. Then I bought a 9 cubic foot Whirlpool chest freezer for $300. It's bigger than what I was planning on, but it fit in the space very well and came with two baskets. Under one of the baskets, I zip-tied the temp sensor and fan (set to turn on when the fridge does). So I could return the freezer to stock in seconds.

It's certainly efficient. I had it set to turn on at 36 F, with a two degree drop, and it runs for about 6 minutes every hour. The killawatt says about 0.25 kwh/day, or 20 times less than my old fridge. The 13 cu ft freezer uses about 0.62, but I haven't tested this in the summer, or with the increased opening as my main freezer.

I've only been using it a week or so, but so far it's been easy to use. I need to work on shelving... it's not like a freezer where you can just stack stuff. It's got plenty of space as-is though. Condensation is a big deal: I'm going to put down some rubber shelf liner stuff in the bottom to help keep the things out of the water. I think the constant humidity would cause mold and mildew if turned up into the 40's. I'll know more about it as I use it longer-term.

[omgwtfbyobbq]

That's at least $200 per year in savings!

[GasSavers_Randy]

Originally Posted by omgwtfbyobbq

That's at least $200 per year in savings!

It's about $0.085 per kwh here, or $150 per year. Very good payback though. It also pushes me down to the 1.5 cent cheaper marginal rate.

These things aren't SUPER efficient: a sunfrost would beat this combo by at least 10%... for $3000. The DIY fridge delivers amazing bang for the buck.

[Telco]

Wow, the things some people come up with. I like this idea, but my wife hates chest style freezers because it's hard to get at everything. Not an issue for me being as I'm 6ft 4, but she's 5ft 3 and can't reach over to get to the bottom. If she gets a foot stool to get high enough, she runs the risk of falling in .

So... if I were to do something like this, I think I'd have to build a shelving system to go inside. I envision 3 shelving units that divide the fridge into thirds, with each shelving unit having its own standalone support structure. The shelving would be on sliders to allow the shelves to come up, with a spring assist to help lift the shelves up and down, one handed. Would need a counterweighted system that provides more assistance when heavy and less when light for this to work well. With this, you could reach in and lift a shelf and get anything on it, top to bottom, then slide it back down, without having to root around moving stuff to see what's squashed on the bottom.

I'll have to give this some thought...

[tulsa_97sr5]

Saw this a while back and love the idea. Very cool to see people here using it too. Ever since I first saw it I've had this crazy idea that I could build something like this around our bed and cut way back on AC usage.