A compressor fridge that takes only 0.1 kWh a day?

scotjimland

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I've been thinking on replacing the RV fridge with a small domestic compressor one and run it off the inverter, while looking for an energy efficient one I came across this very interesting article which basically uses a domestic chest freezer as a fridge which uses only 0.1kwh per day, or about 8ah per day, this would save a lot of LPG.. and be a lot cheaper to run.

Read more here http://www.treehugger.com/files/2005/07/man_retrofits_f.php

and download the pdf.

http://www.builditsolar.com/Projects/Conservation/chest_fridge.pdf

Comments, pitfalls .. ??
 

American Dream

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Sounds like a good idea Jim in one respect.

Have you considered the noise aspect of a compressor based unit or won't it really affect you?

Won't there be a "switch-on" surge every time the compressor kicks in?How will the inverter handle that unless it's rated approx twice the running rating of the unit?

I guess you've probably already taken these things into consideration.
 
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scotjimland

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Sounds like a good idea Jim in one respect.

Have you considered the noise aspect of a compressor based unit or won't it really affect you?

Won't there be a "switch-on" surge every time the compressor kicks in?How will the inverter handle that unless it's rated approx twice the running rating of the unit?

I guess you've probably already taken these things into consideration.
Hi Steve
From what I read the noise will be minimal also and the cooling cycle is aprox 90 sec every hour..
Power won't be a problem, I have a Victron 70A/ 1600 watt inverter fitted.

I'm really looking to the future when, not if, the yank fridge goes belly up, I would like to pre empt that event and either fit a small domestic compressor fridge or convert a chest freezer to a fridge..
Benefits are it's cheaper than a yank replacement unit and less use of LPG and dependance on EHU..

Downside to the chest fridge idea is access to contents, but that can be overcome, downside to domestic cabinet fridge is higher watts per day.

The only compressor chest fridges I have seen are relative small units made by Waebco and are little more than cool boxes.
 

Enodreven

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Nov 28, 2007
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Hi,

These appear to be able to supply a chest type fridge and while you can't accurately compare front opening with top opening as there dosen't appear to be an exact size for size, none the less the chest fridge when compared to its nearest size for size front opener does seem to be a lot more efficient.

http://www.rpc.com.au/products/appliances/fridges/fridge_spec.html

I did have a link to a site where someone had carried our comparison tests and costings on using a purpose made 12/24 volt compressor fridge against a 240 volt unit powered through a inverter, and from what i can remember the inverter had to be quiet a lot larger to handle the compressor starting load, and i think the outcome was that it really wasn't that competitive, However it was an old artical and some of the prices quoted were very high against the costs now. If i find the web site i will post it,

I would be very interested in the results of using a inverter ??

very interesting subject

hope that helps

Brian
 

kijana

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Certainly agree with the amount of LPG consumed by the fridge, Jim.

A very interesting article, supported by sound physics. We've never bought a vertical freezer because it was obvious you have to re-freeze its entire volume of air every time you open the door.

I guess the problems of a CFAF are ergonomical: since kitchen floor areas are often small (especially in an RV!) we tend to build upwards, like Staten Island.

The second problem is that chest freezers tend to have stuff thrown in at, and retreived from, the top. Thus over a period of time, one forgets what those shapeless filmwrapped items lurking deep at the bottom are (hence the term UFO, for 'unidentified frozen objects').

So I think the key to making a fridge practical in a chest format is racks. Tom Chalko alludes to this in his piece. Maybe you could devise vertical stacking racks that could be withdrawn upwards (rope & pulley?) so that everything in them could be accessed from the front. In this way, the body of chilled air is undisturbed and the efficiency maintained. It would also raise the bottom layer of goods off the fridge floor by an inch keeping it clear of liquid residues - and make cleaning much easier.

I look forward to hearing how you get on if you go with this.

Bruce
 
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scotjimland

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Hi Bruce .. and thanks for the link Brian

One step ahead, now found a thermostat (kit) that will do the job..

http://www.esr.co.uk/velleman/k2649.htm

Small chest freezers are relatively cheap to buy at around £100, for example this Norfrost which has a top basket where everyday stuff could be stored, milk, butter, cheese etc with plenty of storage underneath for vegetables, cold drinks etc. It would sit in place of the present fridge/freezer.

Downside is having no freezer but to be honest, we fill ours because we have one.. it's not a 'must have'

This idea is becoming very attractive..
 
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