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Running a refridgerator on Solar PV


By gotwind2, Section Remote Living
Posted on Sat Sep 20th, 2008 at 02:50:14 PM MST
Most efficient make/model?

Hello all.

I am looking to buy a refidgerator to cool beers outdoors for a friends party :)
I intend to use it in my house afterwards.

I will use solar panels, and a battery but not sure whether to go the 12/24v route or use an inverter and run a mains powered refridgerator (fridge).

I have google searched the board, and it appears most fridges consume 10 times the normal running power in the first minute, suggesting a big inverter required?

Here in the U.K all white goods have to display an energy efficiency label, from A-G ('A' being the most efficient). most fridges are now Rated A, some B.

Has anyone got any advice on a specific make and model that is most efficient, or any general advice on making such a purchase.

Thanks in advance.
Ben.
Running a refridgerator on Solar PV | 13 comments (13 topical, 0 editorial)

Re: Running a refridgerator on Solar PV (3.00 / 0) (#1)
by DamonHD (d@hd.org) on Sat Sep 20th, 2008 at 08:54:21 AM MST
(User Info) http://www.earth.org.uk/

Hi Ben,

My investigations suggest that even a small 12V 'efficient' fridge can easily use as much as a big (as tall as me) fridge/freezer.  Our is rated at 0.75kWh/day though actually uses 1.1kWh/day, but that's still less than the 12V ones I've looked at.  So I suggest that you consider an A/A+ mains fridge plus good inverter.

FWIW here's my review of ours: http://www.earth.org.uk/note-on-Siemens-KG34NA10GB-upright-fridge-freezer-REVIEW.html

Go and look at http://www.sust-it.net/ and the Energy Savings Trust appliance info.

Rgds

Damon



Re: Running a refridgerator on Solar PV (3.00 / 0) (#2)
by jonas302 on Sat Sep 20th, 2008 at 02:52:46 PM MST
(User Info)

Maybe a chest freezer would work good the door will probly be open a lot that might help keep some cool air in
But maybe its not what you want a home for later



Re: Running a refridgerator on Solar PV (3.00 / 0) (#3)
by gotwind2 (ben[at]gotwind.org) on Sat Sep 20th, 2008 at 03:21:38 PM MST
(User Info) http://www.gotwind.org/index.htm

Thank you Damon and jonas302, Great advice.

I also posted the question on my own forum, with an interesting idea from a contributor today.

Running with the chest freezer/fridge idea, here's the reply.

"Hi Ben.
You might find this interesting and involves using a chest fridge that uses 0.1 KWH.

Please follow the link below"
http://mtbest.net/chest_fridge.html

Be sure to read the PDF file, a bit lengthy, 7 pages.
http://mtbest.net/chest_fridge.pdf

Comments welcomed.

www.gotwind.org


[ Parent ]


Re: Running a refridgerator on Solar PV (3.00 / 0) (#4)
by scottsAI (user name at eml dot cc) on Sat Sep 20th, 2008 at 11:27:19 PM MST
(User Info)

gotwind2,

Above would be my first recommendation. With a caution:
Have not seen ANY collaboration of that project, everybody references it.
Checking the math suggest it's not right. Freezer insulation is a little over twice as thick, heat loss should only be cut to 1/2, 0.1Kwhr/day is better than a 5:1 improvement.
Did not consider the size of it in my comments above. Someday.

If this is a one day party then buy lots of ice and many coolers.
MUCH, MUCH ... MUCH cheaper.
Or a quiet generator with a long cord to keep noise away and/or a big muffler.

If solar fridge is a requirement then:
Buy the best fridge of size you need. Often times the best is not cost effective.
Study it, see if you can add several inches of foam insulation all over.
If fridge is in the sun, cover it with reflective mylar or something like it.
Make sure it has good air flow around the heat exchanger.
Most have the heat exchanger on the bottom leaving the sides/front/top/back free to add foam.
Make it look nice!-)

For Power use two inverters.
Inverter sized to start motor has large quiescent running currents. (7X should do it.)
Split the wiring between control and motor, small inverter on control, large inverter turns on only when the motor needs to run. Many inverters have on/off switch, connect to this. Ask for help...
The large inverter quiescent currents can equal the motor running currents in one day.
Pick out the equipment I will show you the math. (if somebody doesn't beat me to it:-)

Calculated the energy cost to open a 24 cuft fridge/freezer with 15 cuft fridge area is 2.4 watts at 34F in 72F room. Door open 30 sec to 1 minute.

Let us know what you did!

Have fun,
Scott.



Re: Running a refridgerator on Solar PV (3.00 / 0) (#5)
by Norm (peppysue@suite224.net) on Sun Sep 21st, 2008 at 07:10:07 AM MST
(User Info)

If this is a one day party then buy lots of ice and many coolers.
MUCH, MUCH ... MUCH cheaper.
many coolers not too much ice and done a couple
of hours before the party....its a waste to get
beer too cold.....numbs the taste buds and you
can't really enjoy the true flavor of beer and if
you're drinking the stuff just to get inebriated
wouldn't matter if its luke warm or ice cold.
  (hik)

( :>) Norm
[ Parent ]


Re: Running a refridgerator on Solar PV (3.00 / 0) (#8)
by ruddycrazy on Mon Sep 22nd, 2008 at 03:21:06 AM MST
(User Info)

Norm over here in Oz if ya hands dont stick to the beer can then it aint cool enough.

Sheesh don't tell me the yanks are just like the poms warm beer YUK

Cheers Bryan
( About to crack a beer thats been in the freezer for 3 hours)


[ Parent ]



Re: Running a refridgerator on Solar PV (3.00 / 0) (#9)
by scottsAI (user name at eml dot cc) on Mon Sep 22nd, 2008 at 01:33:18 PM MST
(User Info)

Oh yes, the Europeans fascination for warm beer!
Missing my friend's in Ireland this year, they make fun of Americans and their beer COLD. And poring the beer without a head...

I like ruddycrazy's idea, just after opening the bottle if the beer doesn't have some ice in it's not cold enough. Difficult to get just the right temperature to get the ICE without freezing the whole bottle then exploding in the freezer! Yuck what a mess. Frozen mugs helps. Have not done this in a while, sounds good for tonight!!

Have fun,
Scott.


[ Parent ]



Re: Running a refridgerator on Solar PV (3.00 / 0) (#6)
by Jeff (ruralmcguyver at yahoo dot com) on Sun Sep 21st, 2008 at 11:29:39 AM MST
(User Info)

There's a bunch of 12v fridges and freezers out there, all you have to do is a google search, or search this board! Most of them ARE much more efficient than the 110v models, but they come at a cost. $$$-wise, expect at least double the price. You may luck out and find used ones on EBay, but all you have to do is search!

Here's a couple links just in this board:

Reducing fridge motor start current:
http://www.fieldlines.com/story/2008/5/23/115041/076

Stirling Cycle Refrigeration:
http://www.fieldlines.com/story/2008/4/30/151834/419

Try clicking on "Search the Board" on the top-right menu of the main page here, then type "refridgeration" or "refridgerator". It turns up so many, you'll be reading and following links for hours. Even at $500 more than a 110v model, the cost savings of $500/$30per year savings pays back in 17 months. Not to mention, it could be run with even the smallest of RE systems like 1 HF panel set @ 45watts, and 1 - 100-120Ah battery.

I just wish I could afford even $30 for some magnets to make a small genny!
Rural McG



Re: Running a refridgerator on Solar PV (3.00 / 0) (#13)
by wooferhound (tim((NoSpamAt))wooferhound.com) on Tue Sep 23rd, 2008 at 06:08:39 PM MST
(User Info) http://wooferhound.com

If you do a search of the board it may be better to spell "refrigerator" correctly
it is NOT spelled "refridgerator".

W o o f -={(

[ Parent ]


Re: Running a refridgerator on Solar PV (3.00 / 0) (#7)
by DanG on Sun Sep 21st, 2008 at 12:32:31 PM MST
(User Info)

la7qz, a contributor to these forums on occasion, is living aboard the Yacht 'Magic' sailboat down in the Caribbean and needed the best cooler/freezer using the least power, to run off his small wind turbines and solar panels. He chose the Coleman 'Stirling Cycle' chest cooler - found it here in the states and shipped it back home. It has been discontinued for a year or so but there are units around to be had. Good luck with whatever you chose...

http://tinyurl.com/3nwf8t  <-- cooler description



Re: Running a refridgerator on Solar PV (3.00 / 0) (#11)
by la7qz on Tue Sep 23rd, 2008 at 12:55:44 PM MST
(User Info) http://home.no.net/naomij

Hi

The Stirling Cooler has been running fine for a couple of months now. Power consumption is around 600mA most of the time. I intend to improve ventilation around the box which will hopefully lower the consumption even more.

It has five temperature settings from 10 deg C (too warm) to deep freeze. I use the second fridge setting. I'm thinking of buying a second one to use as a freezer.

PS. The first generation of these were apparently rather noisy. Mine is audible, but no problem and I'm a noise sensitive person.

Owen

If you're not living on the edge, you're taking up too much space.
[ Parent ]



Re: Running a refridgerator on Solar PV (3.00 / 0) (#12)
by la7qz on Tue Sep 23rd, 2008 at 12:59:46 PM MST
(User Info) http://home.no.net/naomij

Hi again

I forgot to say, mine was bought on clearance at a Coleman outlet near Detroit.

Owen
If you're not living on the edge, you're taking up too much space.
[ Parent ]



Re: Running a refridgerator on Solar PV (3.00 / 0) (#10)
by SparWeb (sparweb at ANTISPAM_hotmail_com) on Mon Sep 22nd, 2008 at 03:02:32 PM MST
(User Info)

Something I noticed the other day, about refrigerators:

http://www.thebackshed.com/Windmill/FORUM1/forum_posts.asp?TID=1280&PN=1

Thought you might find it interesting.
Steven Fahey



Running a refridgerator on Solar PV | 13 comments (13 topical, 0 editorial)
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