347 kwh per year

[ukjohn]

that is what my fridge freezer eats ( hotpoint ff187e )per year

so what size solar panels would i need to run it ?

i have sorted out my upstairs lights and want to expand a bit over the next few years and just think the fridge would be a good place to start .

any help would be good as i have learn t all i know so far from reading this site.

thanks.

john  

[DamonHD]

Hi,

We have to know where you are in the world, and which way your roof faces for roof-mounted, or else if you have ground space, for starters!

Rgds

Damon

[ukjohn]

a bit of a clue in my name

UK and a lot of south facing roof .

john

[dnix71]

1 kh a day, roughly is consumption. If you are running an inverter there will be some losses. Maybe 1.5 kw hours would be a safer number, esp. in the summer when the fridge has to work harder.

What percent drawdown on batteries are you willing to take? If you don't want food to spoil and cannot go back to the grid, you'll need maybe 3 days battery backup for inclement weather.

How many hours a day of direct sun do you get during the least sunny time of year?

Hours of sun x panels watts must = at least 1.5 kwh per day average.

4 hours x 350 watts or 5 hours x 300 watts is enough

A safe drawdown assuming a full recharge might be 1/2 of the battery's ratings

Three days at 1.5 kwh is 4.5 kwh storage needed times 2 for safe drawdown (no sulfation)

Nine kwh of storage with 3hundred or 3hundred fifty watts of panels.

12.5volts times 720 amp-hours = 9000 watt-hours

[ukjohn]

wow thanks for that

I would stick with 4 hours of sun ( or less ) and would still have mains power.

so if we say 350 watt of panel and 7 x 105aph battery`s would do it .

i know it would take about 40 years to payback but to me it is more about self reliance  

but i think it has given more to think about

thanks .

i love this site.

john

[DamonHD]

Slightly depends where in the UK!

Have you seen this wonderful free tool?

http://re.jrc.ec.europa.eu/pvgis/apps3/pvest.php#

I used it to work out what I needed and it was slightly conservative but pretty damn close.

Rgds

Damon

[DamonHD]

BTW: Remember to size for winter (Dec) worst-case performance and include >=5 days' battery to ensure that your milk doesn't curdle at Christmas...

Rgds

Damon

[Jeff]

I think Dnix's figures look pretty good! Even on the conservative side! 1KwH/day for the fridge is even conservative, so the 1.5KwH he worked with is great for start-up surges on the fridge, plus conversion loss.

Across the pond here, those 700+ Ah of batteries would run around $450-500 even for the better Trojan-clones.

The real kicker would be the 350-400 watts of solar panels. That's why some (on Otherpower) go with smaller solar panels, and add a wind gennie.

That's a pretty good yearly efficiency # for the fridge by the way, a smaller-full size one.

[ukjohn]

thanks for that .

i am still working things out as i go .

the fridge is ok for the price .

http://www.reevoo.com/reviews/mpn/hotpoint/ff_187_e#additionalReviews

that is the fist thing that bust so the first thing that got replaced with an

A rating .

more to come , save it, make it, its all the same.

john

[DamonHD]

We did a Siemens A+ though I had the engineer out since I'm convinced it's using 50% too much power (and they couldn't do anything better than send him out when I called the help line).

http://www.earth.org.uk/note-on-Siemens-KG34NA10GB-upright-fridge-freezer-REVIEW.html

Nominally 750Wh/day, though I've been seeing 900 to 1300.  I think that the auto-defrost cycle may need tweaking.

Rgds

Damon

[dnix71]

It's cheaper to buy a 12 volt fridge than to buy batteries and panels to run a full sized fridge, IF you can get by with a smaller fridge.

I got item 22 from BigFrogMountain, the newer Engel 43.

http://www.amazon.com/b?ie=UTF8&marketplaceID=ATVPDKIKX0DER&me=A21D8415B0SCJI&isPopup=

The Engel can run with a supplied ac adapter or directly from one 12volt battery.

Conservation works and pays better than conversion.

[ukjohn]

thanks Damon that site is good .

bookmarked in my ever growing file .

john

[ukjohn]

I have been looking at 12v stuff more and more.

so far all i have done is all the lighting upstairs , fitted extra fittings and pull switch`s in all the bedrooms , bathroom and landing as it was easy to do from the loft

all the bulbs are 12v cfl except the bathroom , that has 5x 20watt 12v halogen.

i have fitted 100watt of panel and a few 105 amp hour battery`s and it seems to be doing well .

i had to beef up the wiring  to the bathroom as it was getting a bit warm but for now all looks good .

all the 240v bulbs are now cfl

I do think the 12v thing is a good one .

thanks.

john

this was meant as back up power but is now used all the time .

[Norm]

Think it's worth mentioning that....unless you

are already doing that...to have the refrigerator

out on a cold enclosed porch...practically free

refrigeration in the winter time?

[DamonHD]

...though some domestic fridge/freezers may not enjoy being in a cold/damp environment themselves (my handbook warned against it) so YMMV.

But you can always do the DIY student fridge (hanging your milk out of the window in a bag).  That used very little electricity up in Edinburgh in the winter!

Rgds

Damon

[tecker]

 There's really no point in worring about matching what you pay for electricity and the amount you still owe for the materials and lobor included in the solar package .You'll have a solid future and if you match useage the price can go into home equity as soon as someone figures out this is the right thing to do .I 'm sure the waranty will surfice for now.