simple request for fridge that can be hooked up to solar power and how to do it

[soleil_01]

i am in great need of a new fridge- freezer, ive been looking online for energy efficient ones here http://www.greenconsumerguide.com/fridge_freezers.php but have reached the conclusion that they ar rubbish. instead i am going to buy an ordinary one and hook it up to the solar panels on my roof. i like the look of the miele ones here http://www.twenga.co.uk/dir-Appliances,Fridges-and-freezers,Fridge-freezer-431 but beyond picking the pretty one i dont really know how to go about this little diy thing! dont know how feasible it even is really.
has anyone done this with anything at all? we have our panels hooked up to our heating and out lighting but it was the solar panel man who came and did it and i didnt even try to ask any questions, it all looked far too complex for me! can anyone advise? or do i just need to get the man in again?

[Dyslexicbloke]

You could probably have long and involved discussions about fridge motor types and general efficiency but at the same time I doubt that any manufacturer is going to state that their unit will work on anything other than mains power ….

However I live in a caravan and there is a standard under counter fridge in it …. It’s a Lec and almost certainly nothing special.

I only have circa 300W of panels and a 12v 600W modified sine wave inverter, just a cheep thing.
During the summer I run the fridge, on the inverter, whenever there is enough power and it works just fine. The inverter grunts a bit when it starts up, it only 1000W peak, but nothing has blown up yet.

I actually use it as a dump load to reduce the battery voltage when there is too much sun.

It would probably work better if I had a pure sine unit but I cant afford one.

My advice … pick a fridge that is as low a power as you can find, so starting isn’t a problem, and plug it in to a circuit you can switch from inverter to mains depending on the power you have available.
Switch it on and don’t worry about it.

The only mod I have made is to fill the icebox with freezer packs so it runs for long periods, when its connected, and then stays cold for long periods when its off.  If it needs cooling down when there isn’t an execs of power from the PV’sthen I switch to a circuit that is generator fed and run when I am charging the batteries. …

Alistair

[billi]

Hi Soleil

Are you off grid ? Or how are your PV (solar) panels connected to the house ?

Like Alistair said   , if you like to run it totally intendant , you need a Inverter ( about 1000 watt) , battery and a charge controller , but i have my doubts that this is economical ( if you are grid connected )

But you can as well connect a small Grid tie inverter to your house and feed parts of your daily needs in the house from the PV to balance the consumption of the fridge -freezer 

Billi

You can get direct PV driven fridges   or freezer from Stecasolar

[guydewdney]

as an owner of a motorhome with a BIG (for a mh) 24v fridge, which retails at 1500 quid  (I paid a hundred, as new, complete with scratches....) - the wildcamping (ie offgrid) lot reckon that the above advice is generally good - buy an OK small fridge, and run it off a decent inverter.

[tz0c0s]

I was asked to repair, many many years ago, an old fridge.
My opinion was why bother, what can I fix? compressor u/s, gas gone....

To my utter supprise, the only thing electrical, other than the light was a small wire wound heater. This was o/c & I managed to obtain a replacement.
I guess camping fridges that work on leccy or gas must work on a similar principal.

Not sure if you can get a large version or one that has has enough guts to operate a freezer also? These would be low power things, more able to work with solar if you are currently having a problem?

Andy

[soleil_01]

thank you for such sound an thoughtful advice. i will look into these inverters and see what the deal is, maybe get to a shop and have a little poke about to see what these things look like from the back... really appreciate, il be back after my exploratory trip!

[Dyslexicbloke]

My inverter ......
http://www.maplin.co.uk/Module.aspx?ModuleNo=48724

I use it for everything Lappy, CF bulbs, Cooker cooling fans, TV / Satbox / DVD recorder, ....  and Fridge.

Some fussy electronic devices will not like it and others may hum a bit indicating that they are not too happy with the waveform and are probably going to run hot and die reasonably soon.
CF bulbs for example are a bit hit and miss, some work just fine others not at all or only for a short period before packing up.

A pure sine wave inverter would be better in all cases, kinder to the equipment and possibly more efficient but then it is likely to cost at least 3 times as much in the first place.

If you look at heat based fridge’s, usually optional gas / elec for travelling, take note of the cool down time and efficiency, some are appalling.

Lastly don’t be tempted by low voltage electronic coolers, Peltier devices, even the best of these seldom achieve much better than 5% efficiency. Great if it stops your lappy frying but a
very power hungry way to chill your beer.

Alistair

[biff]

hello soleil,
         there might be another way,or another inverter.
    have a look on fleabay for a" back-ups" apc. ups... they usually go for around £25.00. a 650va one,which is 400watt. this is the old model smart ups and is easy started using a toggle switch and another switch to knock out the alarm. pull out the 12 volt battery and use an anderson connector to connect to a 12 volt battery bank. do a neat job and this little baby will outlive a dozen modern type inverters.it is also high quality sine wave and actually trickle charges as well. i have never known one of these to let me down.
                                                  biff

[Simes123]

hello soleil,
         there might be another way,or another inverter.
    have a look on fleabay for a" back-ups" apc. ups... they usually go for around £25.00. a 650va one,which is 400watt. this is the old model smart ups and is easy started using a toggle switch and another switch to knock out the alarm. pull out the 12 volt battery and use an anderson connector to connect to a 12 volt battery bank. do a neat job and this little baby will outlive a dozen modern type inverters.it is also high quality sine wave and actually trickle charges as well. i have never known one of these to let me down.
                                                  biff

Ooh - like this idea.  I have a fairly hefty APC UPS that will soon become redundant.  I wonder if this might be a basis for powering a Solar Voltaic charged, whole house LED lighting circuit.....  Free lighting appeals to me.  Thinking about it, I'd actually be better making the lighting circuit low voltage due to the conversion losses, but suspect I'll have trouble finding LED GU10 format bulbs that aren't expecting mains voltage.

[JohnS]

Go for MR16s.

GU10s are mains voltage but MR16s are 12 volt.

John

[dimogga]

http://en.wikipedia.org/wiki/Pot-in-pot_refrigerator


Or if you're on a north facing window hang your milk outside in a bag. People used to do this at uni halls. Although it was much easier to just drink black coffee.

[Heinz]

The big problem with fridges is the fact that all the carefully cooled air falls out of the front as soon as you open the door, this is going to be more of a problem if you're trying to run it off a small and intermittent suppy, like solar.
 Have a Google for freezer to fridge conversion or chest fridge ....

Heinz

[Ivan]

I think there's a link to a chest freezer to fridge conversion in the download area of the Navitron website.  I use a Sorel controller as a thermostat (expensive way to do it, but dead easy as I happened to have a spare one) to turn a freezer into a fridge. It works very well (has been running for several years) - and uses half of the electricity used by the equivalent fridge model (same manufacturer same size, same age). I also use a Sorel controller to provide a much better temperature control for a fridge I need to run at 10C +/- 1C.

I've used the bag-out-of-the-window trick at University. In fact, in single-glazed properties, between the window and the curtain is pretty good too.

[wookey]

12V GU10 LEDs do exist http://www.alibaba.com/showroom/12v-gu10-led.html
but yes it's much easier to find 12V MR16s.

Plenty of other LED shapes (strips, downlighter units) also exist in 12V form.

[eabadger]

i have a 12v compresor fridge freezer which may be for sale, is old, was on a big boat, then used by us for two years off grid.
has auto switch over to mains when present, then reverts to 12v when shore power is off.

maybe they still sell them new?

steve