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Convert your old fridge into a heat pump

einstein59

I Just joined this forum in the hope of getting some advice about my ideas for reducing my energy costs at home, since my landlord refuses to install central heating and I cannot afford to pay for anything more efficient I'm stuck with expensive to operate electric panel heaters in a cold damp ground floor flat.

However, my low income over the years has forced me to become more resourceful making use of other peoples scrap furniture, electrical appliances and materials for my home d.i.y projects, which has led to the development of a few interesting ideas including a heat recovery method from electric water heater tank.

The recent increase in energy costs has made me even more aware of my own situation, and to this end I have been researching Heat Pump technology as a potential solution to my heating problems at home. Unfortunately it woiuld seem that this type of heating is just as expensive to buy and way beyond my means, so having studied the principle of the heat pump I realised that it is nothing more that a big fridge in reverse.

I would therefore like to discuss the possibilities of using an old (recycled) fridge as a heat pump, in conjunction with a small solar heat collector fitted to my ground floor windows and other sources of potential heat such as waste hot water from bath, washing machine etc. The general idea would be to convert the inside of the fridge as a heat store using heat bricks (old electric storage heater bricks) to build up heat during the day, which can then be pumped out at night when needed using the built in heat pump of the fridge to provide at least background heat for a well insulated room to help reduce conventional electric heating costs.

As soon as I can find suitable electronic components I will be experimenting with a secondhand fridge I picked up for a few quid, a car water radiator, flat plate collector (CH radiator) and an idea I came across on the web for using aluminium drinks cans as a window air source heat collector.

Any ideas, advice and comments welcome, although my internet access is limited to a few hours a week at a friends house or the local library, so my replies may be delayed for a day or so.

 

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Submitted by einstein59 on Tue, 10/07/2008 - 13:27.

skyeman
Re: Convert your old fridge into a heat pump

Hi

This is an interesting article as I have just come into possession of  some APV Hall 6kw industrial freezer units which I am hoping to do the same with, the compressors are 3phase, but I was considering to power the units direct of a wind mill, rather than change the energy.

I live on the West Coast of Scotland and wind is not a problem.

I  am building a new house and have installed underfloor heating pipes

 

cheers

 


Fri, 10/17/2008 - 02:05

athena
Re: Convert your old fridge into a heat pump

If your hot water is included in the rent that will be your easiest way to heat your place using a rad that steals energy from the existing system.  Don't think you'll get away with that for long. 

A pop can collector works great and if you can take air from the floor below and route it back into an upstairs window you will be able to heat totally if the sun can shine onto the device.  Landlord might go for that fix.

To recover solar heat already entering a window does not make sense.  A passive brick will store energy and release when the temp drops.

But a fridge?  You will need an external solar water heater that can heat water ( or working fluid) which could be stored in fridge and released later - Rube Goldberg  would be proud.

Stick with it.  When you have learned more than the rest of us know, you can tell us how to do it.


Wed, 10/08/2008 - 07:11

ctyankee
Re: Convert your old fridge into a heat pump

Congrats on recognizing the fridge-as-heat-pump paradigm.   At almost any outdoor temperature above the freezer setpoint the unit should give you a COP > 1.0, which is exactly what you get from an electric resistance heater.

If you've got the mechanical skills to perform the modification you should do just fine.  If you can handle the noise. :^)


Tue, 10/07/2008 - 14:15

athena
Re: Convert your old fridge into a heat pump

ct, 

If this system is set up like a heat pump that moves heat from outside to inside we should expect a 5:1 return on energy input when the weather is mild, but when the temp drops the efficiency goes down and he'll need a solar heater on his outside hardware to keep his return on energy usage above 1:1.  At that point it is a solar system.


Mon, 10/13/2008 - 15:04

ctyankee
Re: Convert your old fridge into a heat pump

That's true, and there lies the rub.  When the weather is mild he needs less heat... When the weather is *cold* the performance falls off :^(  But you know what they say; make hay when the sun shines.

All I was saying was that even if the outside temp goes polar you'l still do as well as an electric resistance heater.  That's not really a goog reason to use a HP with a price premium.  But the the avg temp is mild then it makes sense.


Tue, 10/14/2008 - 06:07