h a l f b a k e r yIt might be better to just get another gerbil.
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A compressor fridge works by pumping the heat out of it's inside to the outside, which makes the back of the fridge (condenser) hot. Especially in summer we have to get rid of the heat from the room by air conditioning which is another expense. Why not have a fridge with the condenser, that is separated
from the fridge and connected with long pipes (just like the split-type air coolers). Then the condenser could be placed outside - for outside air cooling or, maybe even better, dug into the ground so that it has a constant temperature. Or another version - a combination of split-type air cooler and fridge in one unit - the outside part of the unit would be just one so this thing could be even cheaper than two separate units (an air-cooler and a fridge).
I expect this fridge to consume only a fraction of energy compared to today's "modern" fridges.
Efficiency
http://hyperphysics...mo/heatpump.html#c3
Efficiency of a thermal pump [slovakmartin, Sep 02 2005]
Coolant Plumbing
Similar [Worldgineer, Sep 02 2005]
refrigerator-fish-tank combi
Also relevant [Worldgineer, Sep 02 2005]
[link]
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This would be best in a hot climate, in the temperate UK you would want a system which talked to the aircon/heating and decided whether the excess heat should be dumped outside or inside. I'm sure your idea is already baked in commercial refridgeration systems, but I haven't seen it implemented domestically. |
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// I expect this fridge to consume only a fraction of energy compared to today's "modern" fridges.// - Why? Please explain. |
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Is the condenser wrapped around plumbing for your wash basin? More rapid wash water warming. |
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It might cut a few % off, but not a large amount. Seems like we've done this one before somewhere. |
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This seems like a great idea to me. When it's cold outside, air has
to be heated for the home and then cooled back down for the
refrigerator, which seems like a big waste of energy. |
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If the
compressor had a thermostat built in, it could just switch to an air
pump when the temperature was sufficiently low. |
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wagster,
the the theoretical coefficient of performance of a fridge can be calculated as Tc/(Th-Tc), where Tc is the temperature of the cold side and Th is the temperature of the hot side (the condenser of a fridge). If we move the hot side to a colder place - outside the building or better - dig it into the ground, the (Th-Tc) part of the formula will rise min. 2 times! That means that one unit of electrical energy would pump twice as much heat in this setup. Doubling the efficiency is a huge improvement in my book... |
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That sounds eminently reasonable. Unless of course you live in Delhi. |
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slovak, Your estimates are way off. Doubling the efficiency is not even theoretically possible due to the working temperatures involved. Remember that your formula is dependent upon using an absolute scale of temperature (Kelvin). If you drop the surrounding temperature of the environment by 15 degrees, you might improve the effective condenser heat transfer rate by maybe 5 degrees. So if you add 5 degrees to your Th-Tc difference and then divide that by 273 result by 273 K, you've only improved by 1.8% in thermal efficiency. |
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If it cost you less than $100 to run a refrigerator, and you could save half of the energy usage in the winter, that would be twelve or thirteen dollars. The cost of installing a condenser outside, and the extra Freon, etc., would be $500 minimum. For a payback of 38 years. Taking into account the cost of money, there would be no payback at all. Another factor: the unit would have to be larger to pump against outside temperatures during the summer.
[RayfordSteele] Slovak is right. The maximum (Carnot) COP of a heat pump is the hot temp divided by the difference between the hot temp and the cold temp. You don't divide by 273--the hot temp in kelvins is in the numerator. Doubling the efficiency is not even possible, you say? Sure it is. If there is no difference between the hot and cold side, the ideal COP is infinite. If the hot side is colder than the cold side, you could even use it to produce energy. |
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//maintain a tank full of tropical fish (in a temperate climate, that is)//
Or temperate fish in a tropical climate? |
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Yeah, we did this one before, including all the points in all the annos, including |
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We definately did something similar to this idea (I posted one myself, but was MFD'd redundant), but it appears to be gone. |
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