# Solar freezer?



## ||Downhome|| (Jan 12, 2009)

well Ive been kicking this idea around awhile, nothing new by any means.
I know there are commercial cooling units that use solar and the absorbtion cycle for air conditioning. My ultimate goal is to be independent of the grid.
the one pitfall I keep runing across is a full time freezer, fridge is easy enough.
Im sure some of you have seen the modified chest freezers being used as a fridge.
Yes I could do as the oldtimers did and store Ice from the winter through the summer. either cut it or freeze it like big ice cubes but want to avoid the labor factor there.
My Idea is something like a root cellar Insulated very well and for the cooling 
please see the first link. I was also thinking of including a wall of 55 gal plastic
drums partialy filled with water (to allow for expansion) let them freeze in the 
winter. I would also have a double door to help conserve the precious cold.
(outside door and a inside door creating a static area) 

heres the link
http://www.scribd.com/doc/6599651/How-to-Build-a-Solar-Icemaker


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## ||Downhome|| (Jan 12, 2009)

no replys common some one has to have some ideas on this??


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## ET1 SS (Oct 22, 2005)

The solar freezer that I have seen is fairly small.

But it is a neat idea.


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## ||Downhome|| (Jan 12, 2009)

can you point me toward it or describe it. Im going to pay havoc trying to build this as the ammonia is a top ingredient in a certain illegal substance and its no secret to most folk what that is. but this was something cool I came across theres plenty of stuff on the web on the process and I found the little propane tank absorbtion fridge Ice maker. but anything shared will be most appreciated.


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## artificer (Feb 26, 2007)

Here's a link to the Sundanzer solar freezer/refrigerator.

As a refrigerator, it takes about 100whrs per day. As a freezer, its more.

How much volume do you want for a freezer?

Ammonia is controlled, but not hard to get. Its a standard fertilizer, so its cheap as well. You mostly have to prove that you have a legitimate use for it, and a SAFE container to store/transport it in.

I like the solar freezer more than the icemaker, since the freezer will cool to lower temps. Hmm... I guess you could make some super ice that melts at less than 32degF...

Michael


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## silosounds (Nov 13, 2004)

have you checked into any refrigerants that aren't so hard to get or maybe salvage some ammonia out of old refrigerators and store it in propane tanks. if you could find salvaged trailer refrigerators somewhere. in the a/c trade we reclaim refrigerant all the time. all you need is a gauge set and tank. although I've never tried ammonia its pretty toxic.
We tried freezing barrels in our area 4-5 and couldn't get them to freeze all the way , we had to fill them half way to get them solid. and as they thawed, they ran all over the floor because the seems split on the bottom from freezing. but there's got to be a way to do this i,m going to ponder this.


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## ET1 SS (Oct 22, 2005)

http://www.homepower.com/article/?file=HP53_pg20_Vanek


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## ||Downhome|| (Jan 12, 2009)

Silo Im thinking your problem happened from to slow of a freeze. I could be wrong.
up here in the middle to the end of january I could freeze a whole cow no problem 
this year has been very frigid! but I thank everyone keep those thoughts comeing.
artificer that wasnt the solar I was thinking did you happen to check out the link I posted. Thats what I was thinking about with the sun provideing the heat to power the 
freezer. as far as volume Id love to be able to hang whole carcass's in there. I know Im 
reaching a bit but I think I can work something out. but still appreciate all the help I can get!


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## artificer (Feb 26, 2007)

I didn't check out the first link, sorry. The system shown makes 10lbs of ice. Thats 144btu/lb x 10lbs = 1,440btus/day

That is not a lot of cooling. For example, lets build a 6x8 room with 7' ceiling. Use 6" of extruded polystyrene foam insulation. You get R-30 and 292square ft of surface. (ignore door for now) That means that to get to 0degF with an outside temp of 55 (buried like a root cellar) you need 535btu/hr. The 1440btu's only have enough cooling for 2.7 hrs, and thats only at freezing.

You need 10 times the cooling power for this freezer. A smaller size will need less cooling, all the way down to the electric one I mentioned.

I guess the question to ask is: how much do you want/can spend on this thing? I've seen 10ton commercial solar cooling systems, but I can't afford to pay for them.

4000 gallons of ice can supply 1 years worth of cooling for the above system. If you're talking about atmospheric freezing, you'll need less than that. How much less? How fast can you cool/freeze this water?

Here in Wisconsin, I could freeze the water in winter. If I had a radiator that could cool a 50hp engine (assume 50hp of cooling, it would actually be more) that would give me about 125,000 btu/hr. The required 4.7mbtu would only take less than a few days with the recent sub zero temps. Thats assuming ideal cooling/heat transfer. Even with inefficiencies, it would be more than easy to do over the length of winter.

I think you will be far better off making an ice house with a massive ice block. I wouldn't use barrels, since they don't hold much. The 4000 gallons needed will be 534cubic feet. At 6' x 8', that is 11 foot tall. That means it doesn't fit into the above freezer. You need a bigger room, which means more ice, and an even bigger room...

As for solar power to cool it... 535btu/hr x 24hrs/day = 12,840btu/day needed. Thats 3,775 watt hrs/day. At 1,000watts/meter (850w/yrd), you need 4.4square yards of collector at 100% efficiency. 20% efficiency means 22 yards, or 200square feet of area.

Its an interesting problem. Not to dissuade you, just putting the project in perspective. I'm also interested in something like this.


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## DMD Farms (Jun 8, 2008)

Don't know if this helps, but here is a link to some smaller units

http://www.backwoodshome.com/articles2/yago102.html

I would also like to build a root cellar sized unit, maybe out of tires earthship style.


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