the Otherpower.com Discussion Board || refrigeration ?

Front Page - [Homebrewed Electricity-- (wind) (solar) (hydro) (steam) (controls) (storage) (mechanical)] - Classifieds - Site News
Everything - Newbies - [Remote Living-- (housing) (heat) (light) (water)] - Rants & Opinion - Diaries - Our Products

refrigeration ?
By bob g, Section Remote Living Posted on Wed Nov 17th, 2004 at 10:18:49 PM MST
what happened to whomever that tried freezers as fridges?

still working on the offgrid plan, and am back on the refridgeration kick, which i have
concluded that my direction is towards using a small chest freezer with a fridge thermostat, to get the thing to operate in the 38-42F parameter.
found a source for small and fairly efficient freezers, that average about 770 watt/hrs per day consumption as a freezer, and was thinking that by changing the thermostat perhaps i can trim it a bit more.
i remember following someone on the board that was working on this plan,
how did it work out?
bob g

refrigeration ? | 12 comments (12 topical, 0 editorial)

Re: refrigeration ? (3.00 / 0) (#1)
by Mentally Moribund on Wed Nov 17th, 2004 at 11:42:44 PM MST
(User Info)

have you considered using a thermoelectric fridge? They are efficient, especially if combined with geothermal(depending on where you are located). Generally thermoelectric fridges can only reach 10 to 15 degrees farenheit below the tempurature outside of them. In the midwest the average ground temp in 52 (approx 4' below surface) 52 subtract 10 to 15 degrees and your good to go. http://www.smu.edu/geothermal/2004NAMap/Geothermal_MapNA_7x10in.gif this site will show you the temp of your ground

Re: refrigeration ? (3.00 / 0) (#2)
by Chagrin on Thu Nov 18th, 2004 at 04:28:58 AM MST
(User Info)

Are you sure about the efficiency of thermoelectric refrigerators? I believe that with current technology, standard compressor models are still much more efficient.

I do wish it were possible to easily route the coils of my refrigerator outside in the winter though. This, like solar water heating, should be a required feature of all homes.

[ Parent ]

Re: refrigeration ? (3.00 / 0) (#5)
by RatOmeter on Thu Nov 18th, 2004 at 09:31:04 AM MST
(User Info) http://www.rato.us

Thermoelectric (peltier) devices are not very efficient compared to alternatives. Good for spot cooling (for CPUs) but for refrigeration, they're more novel than viable.

[ Parent ]

Re: refrigeration ? (3.00 / 0) (#3)
by John II (jjones2(at)inetvisions.net) on Thu Nov 18th, 2004 at 07:54:16 AM MST
(User Info)

Just to go on record. I'm also interested in doing the same thing. Sounds like to me it should work. And yes.. I haven't had the nerve to hack into ours!

One word of caution, The evaporator and condenser lines are run on the inside walls of most modern freezers, so if you attempt to drill a hole for either an external thermostat or electrical wires, you run a high chance of ruining your deep freeze. I have tore into several, and I'm not certain, but I think the box over the compressor may be safe to go through ? Doe's anyone have any input on the safest place to drill, or a method of determining this ?

John II

Re: refrigeration ? (3.00 / 0) (#4)
by Volvo farmer on Thu Nov 18th, 2004 at 08:34:33 AM MST
(User Info)

All the chest freezers I've seen have a hollow tube that runs from the ouside of the box near the compressor and is adjacent to an evaporater line inside the box. The thermostat capillary tube is fed into this tube to read the temperature. Most of the adjustable controls I've seen have a bulb at the end of the capillary tube that's too big to fit into this tube though. Check out this Danfoss universal. It's what I would get if I were doing such a project. For this type of experiment, you want an adjustable set point AND an adjustable differential.
http://www.rparts.com/Catalog/Major_Components/controls/controls.asp

Instead of drilling a hole, why not just put the skinny part of the cap tube under the door gasket and dangle the bulb in the box? If you wanted to make it perfect, you could file a little groove in the top of the box so that the tube would not distort the gasket at all.

It's a shame you can't find chest freezers with the separate condenser coils anymore. It would make it easy to super-insulate the box. If I had more time for projects, I'd make a super-insulated chest type box, about 8-10CF with 6-8" of insulation on all six sides, then I'd put the guts from one of those dorm-sized friges in it. If a person was careful, he wouldn't even have to break the sealed system, just a little rearranging of the lines would do it.

Volvo Farmer

May you always have success in your quest to irritate those who you despise. -Ben Goode
[ Parent ]

Re: refrigeration ? (3.00 / 0) (#6)
by whatsnext on Thu Nov 18th, 2004 at 10:44:10 AM MST
(User Info)

I'm pretty sure that you can still find freezers with seperate condenser coils. Just look at the bigger ones. The problem with the seperate coils is that no one ever cleans them and sooner or later your compressor runs full time.
John........

[ Parent ]

Re: refrigeration ? (3.00 / 0) (#9)
by Volvo farmer on Thu Nov 18th, 2004 at 06:29:09 PM MST
(User Info)

Next time you're in Home Depot or Sears, try and find one. I repair appliances for a living and haven't seen one made with external coils in about 15 years. I haven't seen everything out there but I'm pretty sure you can't buy one new. If the coils are cooled by convection and sit on the back of the unit, dirt and dust are a non-issue. It's the fan-cooled coils that live under refigerators that get full of stuff and need to be periodically cleaned.

Volvo Farmer

May you always have success in your quest to irritate those who you despise. -Ben Goode
[ Parent ]

Re: refrigeration ? (3.00 / 0) (#10)
by nack on Thu Nov 18th, 2004 at 07:01:15 PM MST
(User Info)

Why drill? A spring clip will hold the sensor-bulb just fine - hell, a lump of sticky tar will hold it OK. I would even go so far as to guess that a modern refrigeration device probably has a bunch of insulation around the cold box, you could just wedge the bulb under the insulation.

[ Parent ]

Re: refrigeration ? (3.00 / 0) (#7)
by nothing to lose (nothingtolose175 at yahoo.com) on Thu Nov 18th, 2004 at 12:28:30 PM MST
(User Info)

Can't you just turn down/up the thermostat on the freezer as it is?
Maybe mine was an older model or maybe not working as cold as it should have been, but I did this before. I kept everything just above freezing, like about 40. I don't like my stuff frozen, but the closer it is the longer it lasts.
My reason for doing it wasn't power though, I had no money and no fridge at the time, but got a cheap freezer for a couple bucks at a yard sale. It seemed to work like a new one, just looked rough, a little rusty on the top from sitting in a garage.

I'll be experimenting with low power fridges also soon myself. My plan is to run cold water from the well through a heat exchanger to cool the water in a barrel which the coils will sit in. And I plan to also burry the barrel to get ground temps when the well hasn't been running. Part of my preheater for the hot water tank and solar system. I don't expect to do much for heating water this way and a 55gal barrel, but it should keep those coils cold!

If you try water cooling, remeber they still use lead in some solders, maybe the coils, so keep it seperate.
.
nothing to lose

Spelin and tpying are my strong points, not electronics.

Re: refrigeration ? (3.00 / 0) (#8)
by Volvo farmer on Thu Nov 18th, 2004 at 06:15:18 PM MST
(User Info)

I don't know if water cooling the coils is such a good idea in a cap tube system. The length and diameter of the cap tube are designed to work with air cooled coils. If you water cool the coils, the high side pressure drops and the refrigerant turns into a high pressure liquid further up the condenser coil than it normally would. I'm not exactly sure what the effect on the system would be but my guess would be reduced efficiency.

Volvo Farmer

May you always have success in your quest to irritate those who you despise. -Ben Goode
[ Parent ]

Re: refrigeration ? (3.00 / 0) (#11)
by SDO on Fri Nov 19th, 2004 at 12:50:27 AM MST
(User Info) http://alternativepower.dyndns.org:8080/

Do you have a FAQ location, URL for me to read on this low
power consumption for cooling food? I have thought about
going with a root-cellar (but I have sandstone at about
10" below ground) with a solar/ammonia driven ice maker.
However, if there was a way to keep food cool INSIDE the cabin
I'm building instead of in a root cellar, and I could do
away with the 15-20 foot long ice maker that ran to the cellar,
I would be happier. Any information is welcomed.

SDO-aka-Todd
---
Super Dave Osbourne, Man of a Million Shunts
"Not that I expect the current administration to do anything about it."
[ Parent ]

Re: refrigeration ? (3.00 / 0) (#12)
by TrampArt on Fri Nov 19th, 2004 at 07:16:38 AM MST
(User Info)

After 20+ years of living in the sub-tropics (Florida), without conventional electricity, nor solar, nor hydro, nor wind, nor generator, I am of the opinion that the only refrigerator or freezer worthy of consideration is a propane powered one. Period!

refrigeration ? | 12 comments (12 topical, 0 editorial)

Menu

� create account
� How to use the board
� FAQs
� search the board
� Google search the board
� Old Otherpower Board

Login

Make a new account

Username:

Password:

Total Views

��81 Scoop users have viewed this posting.

Related Links

� Also by bob g

You must be a registered user to post here. It's easy and free, and the link is on the upper right side of your page.
All trademarks and copyrights on this page are owned by their respective companies. Postings are owned by the poster, but may be deleted or moved at the ADMIN's sole discretion. The Rest � 2003 Forcefield.
You can Email the board ADMIN here. PLEASE include the username you signed up with!