Half a croissant, on a plate, with a sign in front of it saying '50c'
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Refrigerator Cold Air Vent

A simple temperature activated venting system
  [vote for,

I don't know if this already exists....it might in more expensive applications. Make a simple vent (an optional add-on for those in cold climates) to allow cold outside air to circulate into a refrigerator. 2 temperature sensors, a fan, and ducting is involved. The adaptation to freezer units could make freezing storage more attractive (during cold months of course). I used to have a refrigerator and freezer unit in the garage for this reason, but each got crapped up over time....and still didn't benefit from the coldest outside air.

A more complicated version would be to seal off the refrigerator unit of the refrigerator and pipe out hot air to the outside when indoor temperatures necessitated cooling....and pump in outside air if the outside is colder than indoor temperatures. This would still improve the efficiency of the refrigeration unit. I have not seen anything like this in my travels...a 15 minutes of net search revealed nothing.

Bob Wade, May 09 2002

climate_20controlled at least partially redundant with this older idea by [bobk] [blind_frog, Jun 03 2002, last modified Oct 17 2004]


       Are humidity levels you might let in of concern? It would be a great addition in our office fridge to let out that funky smell everyone is afraid to investigate.
spartanica, May 09 2002

       I think a heat exchanger with the cold outside air would be better than letting in actual air. Not only is humidity an issue, but odours going in and out, pollution/fumes, and insects might all pose problems. I wonder if the sealed environment a refrigerator provides helps in food preservation over and above the coldness.
pottedstu, May 09 2002

       I'll have to think a bit more about this...but my first take is that the humidity level of indoor vs. outdoor is not going to effect the "efficiency" of the concept significantly. We all know humidity affects the "sensation" of hot and cold in humans... of course cold air inherently holds less humidity....but if cold air is pumped in at 20 degrees....the food, and the refrigerator...should be all the more happy.
Bob Wade, May 10 2002

       What's the advantage of this? Surely it's not energy savings. Refrigerators and freezers these days are very energy efficient. Any advantage would be minimal at best, and certainly not worthy of the effort.   

       I am, however, a proponent of the beer-in-the-snowbank method of beverage chilling.
waugsqueke, May 10 2002

       Energy efficiency, true, but I still pay an electric bill, which I estimate could be $100 or more per year less even if it saves half the cost. When I moved the fridge to the garage, I hardly heard it come on in the winter. After years of passing off this and that...I'm finally starting to believe in savings that add up over time. Most don't believe the new energy saver lights are worth it....but when they went down to $5 at walmart, I bought 15 of em and my electric is signficantly down. Not for those in warm climates. In cold, the large sized freezer becomes much more attractive....something I found hard to justify for the amount extra I was paying for electric.
Bob Wade, May 10 2002

       A refridgerator which draws X amount of electricity will add at least X amount of heat to the room, and in some cases more. If a home is electrically heated, a refrigerator may in many cases be more efficient than a straight electric heater. Since electric heat is generally more expensive than gas, the refrigerator may not be superior to a gas furnace. Nonetheless, it's important to recognize that during the winter, the energy used by the fridge is not "lost".   

       During the summer, however, the situation is very different; any heat given off by the fridge must be pumped out of the house by the A/C. In this case, having the fridge coils vented to the outside might make the fridge itself use more energy, but would reduce the energy requirements of the building's A/C.
supercat, May 10 2002

       Yes Supercat....I do sometimes relish that little burst of warm air blowing on my cold feet on certain winter mornings. But a frig which must maintain a 25 cubic ft cold box to keep running isn't a very efficient heater. If not for my feet one foot in front of the frig...I doubt the "heating bill" would notice.   

       My estimate is that during the winter here in New Jersey, I could save $100 or so total by pumping in outside cold air. In colder climates...even more. I did literally prove the concept by having a frig and freezer in the garage....but as I pointed out....this is an inconvience (dear....could you see if there are vegetables in the other frig.....no thanks).   

       But you've made me reconsider the advantage of "sealing off the refrigeration unit"...and pumping out hot air to the outside....for the possible advantages in supermarkets or other large applications. When the application is large...there must be a significant amount of heat which is thrown off...and this would definitely help the establishment's ability to efficiently cool in the summer.   

       For the homeowner, with one frig....it's probably a wash.
Bob Wade, May 12 2002

       What you need to do is make a new outside doorway in the kitchen, and set the frig in it. Frame it in like that so the door is accessible to the kitchen, and cover it up on the outside so that it's not unattractive, nor in the open sun. Your wife probably hates me now, but oh well...   

       Some more ways to cut down on the frig electric bill...   

       1. Keep the coils clean. Get all that dust, hair, rat's nests, etc, out of there. 2. Replace the door seals if necessary. 3. Make sure the coil heat has somewhere to go and isn't just trapped in a 'fridge cubbyhole. 4. Dip the coils in cool tapwater for more efficient heat transfer. Be sure to replace the water every so often.
RayfordSteele, May 13 2002

       Not terribly convenient or practical for the average home but if you want to really pump the heat outside just build a split system with the condensing unit outside the living space (perhaps even in your swimming pool).
half, May 13 2002

       Several comments have jarred a brain cell. The concept can be made even more effective by designing a "cold air reservoir" ....which could consist of a decorative box constructed on the side of the house...and filled with flexible tubes simply immersed (in the shape of a U) in an open container of water.   

       In cold weather, the water freezes....but expands upward around the tubes in the container. On one side the tubes are collected and become the "input" to the refrigerator.   

       This way....during winter months...even if the air temperature rises to 40 degrees or even higher...the ice becomes a reservoir for cold air.
Bob Wade, May 13 2002

       someone seems to have fallen off its lily pad or something
po, Jun 03 2002

       I do this at my datacenter building, in the name of efficiency since our electricity is $0.16/kwh.   

       Temperature sensing controllers change vents from recirculate to "pump in cold air and don't run the compressors" when outside temperuture is sufficient to cool the computer equipment. The whole building is basically a 68f fridge year round either by AC or by fresh air.   

       A note of caution. if you run the compressor at the same time as bringing in fresh air, you will accumulate condensation and things will ice up. Easy enough to prevent though.
jp498, Dec 31 2004

       BTW, if a building is heated with electricity at $0.10/kwH, putting a gallon of water in the freezer and freezing it will generate about $0.02 worth of "free" heat (if you then dispose of the ice without melting it first).   

       I've sometimes thought that it might be worthwhile to construct a building with a large insulated underwater tank that would be frozen during the winter (by pumping heat out) and melted during the summer (by pumping heat in). I don't think such a system would pay for itself very quickly, but the savings in energy costs could be quite significant.
supercat, Jan 03 2005

       Cool idea...
Monty6, Feb 25 2009

       It's only a cool idea literally, not figuratively. Bob is too focused on moving cold outside air into the fridge to cool it, when the superior solution is to use refrigerant to move the coldness around.   

       If one doesn't mind the capital cost, the most energy efficient solution is to have two freezers, one inside the building, and one outside the building (or in the uninsulated garage).   

       Each would have it's condensor coils in the opposite location of where it is -- the freezer outside would have it's condensors in the building, the freezer inside would have it's condensors outside the building.   

       The inside freezer (with the outside condensors) would be used in summer -- not only would it chill itself, but the heat that leaks through it's insulation would chill the building.   

       The outside freezer (with the inside condensors) would be used in winter. When heat leaks *out* through it's insulation, this acts to chill the freezer, which does no harm. When heat leaks *in* through it's insulation, the compressor turns on, pumping heat from the freezer to the condensor coils, which are inside the house, thus warming the house.
goldbb, May 19 2009


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