Passive Fridge, cooling your fridge in the winter.

Ryland · 03-08-10, 12:25 PM

A few people have done things like put their fridge so the coils on the back side are next to a cold wall, or a small opening in the wall to allow them to cool better in the winter, some have even gone as far as to have ducting and a flap that opens with a fan that comes on to bring cold air from the outside in to your fridge in the winter, all of that is well and good but they all require a decent sized hole in the wall and some weird modifications to the fridge, or for the outer coils of the fridge to be cooler then they are designed to operate at thus causing the refrigerant to stay liquid rather then evaporate like it needs to to function like it's designed.
This is where a heat pipe should work really well, at least for those of us who are heating their houses for 6 months out of the year, a good run down of the design is found on the Sun Frost web site, the makers of some impressive fridges, my parents have one of the very early Sun Frost fridges that they bought in 1988, still working, still in use.
Here is a page on their web site on the topic.
Now it sounds like it would work best if your fridge didn't have a freezer, that is pretty much what I have as it's a single door fridge with a small freezer inside, in the top, we keep it full of ice and forget about using it, if I replace it (the Kill-a-watt says it's cheaper to run then most new fridge we can buy, but it's old and is not going to last forever) I plan to replace it with a fridge without a freezer as well, it's next to the north wall of the outside of my house so it seems ideal, not having the fridge run for 6 months at a time seems like it would be nice as well.
I did write to Sunfrost to ask about a price to make a heat pipe for me, but for the most part its a cooper pipe with refrigerant in it so if I knew the specs I could have someone locally make it.

Piwoslaw · 03-08-10, 01:27 PM

A refrigerator which doesn't use electricity for half of the year sounds nice, but I think this comes at a price. When you put something into a normal fridge, its cooling system "sucks" the heat out of that something, heating the room (kitchen). Then, as heat seeps into the fridge through the insulation or open door, the compressor uses energy to pump that heat back out. The working compressor adds heat to the room (more than just the pumped heat, b/c of efficiency losses). So a normal fridge actually heats the room (using electricity).

The heatpipe would only be used during heating season, so it would be pumping the house's heat (the heat that somehow made its way into the refrigerator) out through the wall and into the cold.

Ryland · 03-08-10, 02:46 PM

That is very true, that is why my kitchen tends to be 4-5 degrees warmer in the winter, it also has a range/oven that creates heat.
The heat that is created by the fridge is heat that is being produced by electricity, electric heat is expensive, so I think I would come out ahead using natural gas to keep my kitchen warmer and let nature keep the fridge cold.

Ryland · 03-08-10, 08:18 PM

I got an Email back from sun frost it is as fallows:

We are starting to work on this idea
again and may have a unit available this summer. We are trying to ensure
that the refrigerator compartment will not become too cold when the outside
temperature is below the temperature that is needed inside the refrigerator.

====

I've often wondered if you could use water as the working fluid, or something else that would stop working when it got to cold.

03-08-10, 12:25 PM	#1
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	Passive Fridge, cooling your fridge in the winter. A few people have done things like put their fridge so the coils on the back side are next to a cold wall, or a small opening in the wall to allow them to cool better in the winter, some have even gone as far as to have ducting and a flap that opens with a fan that comes on to bring cold air from the outside in to your fridge in the winter, all of that is well and good but they all require a decent sized hole in the wall and some weird modifications to the fridge, or for the outer coils of the fridge to be cooler then they are designed to operate at thus causing the refrigerant to stay liquid rather then evaporate like it needs to to function like it's designed. This is where a heat pipe should work really well, at least for those of us who are heating their houses for 6 months out of the year, a good run down of the design is found on the Sun Frost web site, the makers of some impressive fridges, my parents have one of the very early Sun Frost fridges that they bought in 1988, still working, still in use. Here is a page on their web site on the topic. Now it sounds like it would work best if your fridge didn't have a freezer, that is pretty much what I have as it's a single door fridge with a small freezer inside, in the top, we keep it full of ice and forget about using it, if I replace it (the Kill-a-watt says it's cheaper to run then most new fridge we can buy, but it's old and is not going to last forever) I plan to replace it with a fridge without a freezer as well, it's next to the north wall of the outside of my house so it seems ideal, not having the fridge run for 6 months at a time seems like it would be nice as well. I did write to Sunfrost to ask about a price to make a heat pipe for me, but for the most part its a cooper pipe with refrigerant in it so if I knew the specs I could have someone locally make it.

03-08-10, 01:27 PM	#2
Piwoslaw Super Moderator Join Date: May 2009 Location: Warsaw, Poland Posts: 961 Thanks: 188 Thanked 110 Times in 86 Posts	A refrigerator which doesn't use electricity for half of the year sounds nice, but I think this comes at a price. When you put something into a normal fridge, its cooling system "sucks" the heat out of that something, heating the room (kitchen). Then, as heat seeps into the fridge through the insulation or open door, the compressor uses energy to pump that heat back out. The working compressor adds heat to the room (more than just the pumped heat, b/c of efficiency losses). So a normal fridge actually heats the room (using electricity). The heatpipe would only be used during heating season, so it would be pumping the house's heat (the heat that somehow made its way into the refrigerator) out through the wall and into the cold.

03-08-10, 02:46 PM	#3
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	That is very true, that is why my kitchen tends to be 4-5 degrees warmer in the winter, it also has a range/oven that creates heat. The heat that is created by the fridge is heat that is being produced by electricity, electric heat is expensive, so I think I would come out ahead using natural gas to keep my kitchen warmer and let nature keep the fridge cold.

03-08-10, 08:18 PM	#4
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	I got an Email back from sun frost it is as fallows: We are starting to work on this idea again and may have a unit available this summer. We are trying to ensure that the refrigerator compartment will not become too cold when the outside temperature is below the temperature that is needed inside the refrigerator. ==== I've often wondered if you could use water as the working fluid, or something else that would stop working when it got to cold.