Apparently your fridge is a big part of your power energy bill because it runs 24/7. I wonder if you could rig a system that would run your fridge then mains take over when there's not enough solar juice?

Even if you had a couple of batteries to carry you overnight.

fridge motor is in the 100W range. Nasty bit is it may run all day in summer, 2.4kWh then.

1kW solar panel may do 5kWh a day.

Only if it's a teeny tiny fridge. A large frost-free can pull 800W (about 1HP).

However, it will not run 24 hours a day unless you have an extraordinarily adverse environment.

Note also that current draw will peak even higher whenever the compressor starts, something to bear in mind when considering alternative power sources.

you won't run it on its own on PV. The PV would just offset it.

Am at 4-5kWH a day. Except recently when I had to torch the old paint off.... Includes 2 person fridge in an adverse environment, lucky this summer is not as hot as the last one.

This post has been edited by Morbo: Jan 30 2010, 10:48 PM

Cheers for that

suppose its up to you to do your bit, will get more brown coal fired power stations soon.

How many batteries would a fridge need for 24/7 power supply if a 1kw solar system is installed?

6 x 2v deep cycle acid @ 36kw/h?

1kW PV would more than offset it.

Here is an interesting question. Could you use a solar array to drive an absorption cycle refrigerator?

A 30 tube evacuated tube hot water system has an energy output of around 16kWhr during summer and 5kWh in winter. Technically it would be feasible to run a standard sized fridge with one. The only catch is that you need a cooling tower to allow the cycle to continue.

Or what if you increase COP by immersing the radiant coil in liquid cooling? Send it underground and back up. Fridge turns on, so does a tiny pump.

Works for computers and mainframe servers. Cheaper than running an air conditioner just to keep the server room cold. Google uses 40 foot containers full of servers all modular liquid cooled using absorption cycle. Takes a day to move what would normally be a small office building to a new location with lower running costs. Stack them up, plug them in...

I guess with a fridge, if its liquid cooled you are already gaining COP. If it had both?

This post has been edited by Red: Mar 25 2010, 12:54 PM

Have you heard of Mount Best Solar House? The fellow there has designed a great solar fridge from an old chest heater. It's supposed to b U-beaut!

Link is here - http://mtbest.net/chest_fridge.html

And here's another one by Stecca - http://www.stecasolar.com/index.php?Gefriertruhe_en

simple, you would have to bend over to get into a chest fridge. Next: its all thrown into there, how to stack things? My milk would be buried under cheese and sausages and vegies, I would have to dig up the whole lot.

Bit the same as why has the driest country on earth washing machines with highest ever water consumption (and on top of that toilets with 20L cistern), some people claim its easier to get into a top loader.

This post has been edited by Morbo: Apr 4 2010, 11:45 PM

Or convert one of these:

Haeir Drawer Frezzer

whats the conversion, change setting to +5° instead -18?

lets get a serviette:
assume 1m wide, 0.5 deep and 0.5 wide. Is 2.5m². R1.5, generous, since its only 30mm of insulation. 5° inside, 25° outside.
2.5x20/1.5=33.3W. COP 3,
266Wh per day? And I did not even put 2L milk in that was at 10°and needs to be cooled to 5°, whopping 41kJ, 7min at 100W to cool them down.

The author used a high efficiency well-insulated freezer - a Vestfrost.

The efficiency mainly comes from the orientation of the opening. With a standard vertical freezer, cold air quickly spills out the open door. In the chest freezer warmer air stratifies to the top.

The concept is similar to open supermarket freezers.

This post has been edited by dymonite69: Apr 5 2010, 03:05 AM

I know, but still you would have heat losses through your walls and 100Wh a day somehow fails to convince me. Unless its size of an esky.

For the stars: no idea what the test regime is, does it include opening the door and putting in warm product or is it just the closed fridge running over a period of time.

This post has been edited by Morbo: Apr 5 2010, 03:23 AM

Vestfrost quote 0.7 kWH/day for standard use.

If you compare external vs internal dimensions of the product, wall thickness is estimated to be 230mm.

Perhaps R 6.3?

This is several times what you estimated and brings it around the figure quoted by the author.

that one
http://www.naturaltechnology.com.au/vestfr...tfrost-Info.pdf

does not look like 250 mm walls, not even 2x125 to get 250 mm. should check R-value of styrofoam tonight, won't be aerocell....

there you have it:

http://www.foamsales.com.au/information/polystyrenervalues/

average fridge may have 30 mm, so I was pretty gracious?

This post has been edited by Morbo: Apr 5 2010, 09:20 AM

next one up: footprint. Conventional fridge goes nicely into a kitchen, chest with door on top wastes plenty of space. Would have to live in the laundry or so. Kitchen may be conditioned, even insulated walls, makes live easier for the fridge. Laundry rather not?

Maybe something like in a morgue, several drawers in a cupboard? Makes it easier to shift trough things, too.

I really like commercial kitchen fridges where in a home the lower cupboards are replaced with a fridge and freezer. You can then have more insulation and as each door is smaller the amount of cold escaping is reduced. It also streamlines the cooking process. Each section can be stacked with separate items and the space left in the kitchen is used for dry goods.