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Protecting your fridge + super frugal fridges

Posted: 24 Jun 2008, 23:20
by Adam1
At the last Powerswitch social here in London, Adam2 had some good tips about fridges, which I forgot to note down and which may be of interest to others on the forum.

One was a device for protecting fridges from the effects of brownouts (when the grid voltage drops significantly). Brownouts can damage fridge compressors. I don't know if modern fridges are better protected in this respect or if all fridges and freezers are vulnerable.

The other was a recommendation for a super frugal fridge.

Can you help Adam2?

Posted: 25 Jun 2008, 07:27
by Pip Tiddlepip
I know your question was to Adam2 - but have a look at this; non-electric doom fridge! I'm going to be making the pot-in-pot system myself as soon as I can find suitable pots:

http://www.selfsufficientish.com/fridge.htm

Posted: 25 Jun 2008, 09:29
by adam2
The article in question was previosly sold by RS components and presumably also available elswhere.
May still be available, but I cant find it on the website.

Low mains voltage is apt to destroy compressors in fridges, feeezers, air conditioners, de-humidifiers, ice makers, beer coolers and similar appliances. This is because the compressor "tries" to maintain the same output, which at the lower voltage means a higher current.

Very brief power failures are also liable to destroy compressors in the above types of appliances. This is because when the motor restarts it is heavily loaded due to the high pressure on the discharge side of the compressor (if the power is off for longer, the pressures on the suction and discharge sides of the comprssor equalize, and the motor starts unloaded)

The compressor protector refrered to above, turns the power off in case of supply failure or low voltage, and does not restore the power to the compressor until some minutes have passed.

I will atempt to find a source of these articles.

Posted: 25 Jun 2008, 10:02
by adam2
As regards very high efficiency fridges and freezers, the most well known brand are sunfrost
http://www.sunfrost.com/refrigerators_main.html

These are made in the USA but available worldwide, they use very little power and are said to be more durable.

For off grid use I would suggest the DC models in order to avoid invertor losses, and reduce reliance on the invertor.

Posted: 25 Jun 2008, 10:50
by adam2
Pip Tiddlepip wrote:I know your question was to Adam2 - but have a look at this; non-electric doom fridge! I'm going to be making the pot-in-pot system myself as soon as I can find suitable pots:

http://www.selfsufficientish.com/fridge.htm
In UK conditions you will probably be dissapointed with the performance of any cooling device that relies on evaporation.
Even in ideal conditions, evaporation produces only a modest cooling, in the humid conditions common in the UK, evaporation and therefore cooling will be very limited.

Posted: 25 Jun 2008, 10:54
by MacG
adam2 wrote:As regards very high efficiency fridges and freezers, the most well known brand are sunfrost
http://www.sunfrost.com/refrigerators_main.html

These are made in the USA but available worldwide, they use very little power and are said to be more durable.

For off grid use I would suggest the DC models in order to avoid invertor losses, and reduce reliance on the invertor.
Last time I looked at SunFrost they were not specially energy efficient at all. They consume very little electricity when running, but that is easily eaten up by a higher purchasing price. By running a SunFrost, you merely shift the energy expenditure to the early part of the lifecycle of the thing. A high purchasing price indicate high energy expenditures when manufacturing and distributing the thing.

Re: Protecting your fridge + super frugal fridges

Posted: 25 Jun 2008, 11:03
by murpen
Adam1 wrote: The other was a recommendation for a super frugal fridge.
Was it anything to do with: Man Retrofits Freezer to Make an Ultra-Efficient Fridge

Re: Protecting your fridge + super frugal fridges

Posted: 25 Jun 2008, 11:53
by adam2
murpen wrote:
Adam1 wrote: The other was a recommendation for a super frugal fridge.
Was it anything to do with: Man Retrofits Freezer to Make an Ultra-Efficient Fridge
It was not, though the conversion of a chest freezer into a fridge can produce very substantial energy savings as detailed in the link.

Re: Protecting your fridge + super frugal fridges

Posted: 25 Jun 2008, 15:37
by JohnB
murpen wrote:Was it anything to do with: Man Retrofits Freezer to Make an Ultra-Efficient Fridge
B*&&?r. I got rid of my freezer and kept the fridge :(