# Yet another low energy frig concept



## SolarGary (Sep 8, 2005)

Hi,

Someone pointed this out to me as one way to go for a PV powered frig:

http://eveningrainfarm.com/?p=5

Very simple and easy on the batteries.

Gary


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## Tango (Aug 19, 2002)

Anything but a Sundanzer would require a new inverter for me, so I am sticking with my Sundanzer 5.8 c.f. plans. Just another month to go! :baby04: If anyone uses a chest style fridge and has any suggestions about how best to utilize the space, I'd love to hear them. I don't think it will be that difficult with 5.8 c.f. of space but I've no idea what to expect.


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## mightybooboo (Feb 10, 2004)

Tango,we put various items in plastic bins in our chest freezer.Beef/pork/dairy,etc.
Sorta works,still a pain.

BooBoo


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## mightybooboo (Feb 10, 2004)

SolarGary said:


> Hi,
> 
> Someone pointed this out to me as one way to go for a PV powered frig:
> 
> ...


I think I would prefer the guys with the beer keg thermostats better.I like his idea of thermal mass in the refer,good point.

thanks Gary.

BooBoo


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## SolarGary (Sep 8, 2005)

Hi MBB,

Do you have a link for the beer keg thermostat?

Thanks,

Gary


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## mightybooboo (Feb 10, 2004)

SolarGary said:


> Hi MBB,
> 
> Do you have a link for the beer keg thermostat?
> 
> ...


http://www.leeners.com/kegging.html#THERMOSTATE

http://ceisites.com/9025.html

I believe this is what they are using.Its on another thread here somewhere....

BooBoo


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## jnap31 (Sep 16, 2005)

mightybooboo said:


> http://www.leeners.com/kegging.html#THERMOSTATE
> 
> http://ceisites.com/9025.html
> 
> ...


So let me get this straight I am gettig confused If I buy this simple temperature controler and hook my ancient chest ferezer up and use it as a fridge keeping the temp. about 40 degrees I will be saving more money than if I use a regular upright fridge? or is this used in the energy eficient sun danzer freezers to turn them into refrigerators and save $. Please clarify I think I need to go back and re-read the other thread till I understand.


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## jnap31 (Sep 16, 2005)

Saw where Jimmy said replied to this question when some one else asked it so I guess I could do better by buying an efficient freezer and turning it into a refrigerator if that is what we wanted? I will only have the money fro one so I will probably just get a freezer and forego a fridge when we get off grid.


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## mightybooboo (Feb 10, 2004)

jnap31 said:


> Saw where Jimmy said replied to this question when some one else asked it so I guess I could do better by buying an efficient freezer and turning it into a refrigerator if that is what we wanted? I will only have the money fro one so I will probably just get a freezer and forego a fridge when we get off grid.


The problem with a conventional freezer as a refer off grid is efficiency losses.Between charging the batteries and inverter losses,you could possibly loose up to 40 % of the power your solar panels make.

So Ive read,Im not an expert on those numbers personally.

For me,Im going Sundanzer all the way.

BooBoo


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## jnap31 (Sep 16, 2005)

I just dont understand where the use of the beer keg thermostat come in is that for people that already have a danzer freezer and decide they want to make it into a super efficient refigerator?


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## mightybooboo (Feb 10, 2004)

jnap31 said:


> I just dont understand where the use of the beer keg thermostat come in is that for people that already have a danzer freezer and decide they want to make it into a super efficient refigerator?


No,it was to take a conventional chest freezer and turn it into a refer,supposedly saves a lot of juice over a chest refer.

BooBoo


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## frazzlehead (Aug 23, 2005)

I use a conventional freezer (sears Kenmore model) hooked up the keg thermostat and plugged into the wall.

I will go plug the killawatt meter into it now, and track it for a bit so we get some real numbers, but it works fine on my offgrid low power budget. 

Cost 1/10 the price of a SunDanzer too ... probably not quite as nice, but hey, it was that or no fridge!


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## mightybooboo (Feb 10, 2004)

frazzlehead said:


> I use a conventional freezer (sears Kenmore model) hooked up the keg thermostat and plugged into the wall.
> 
> I will go plug the killawatt meter into it now, and track it for a bit so we get some real numbers, but it works fine on my offgrid low power budget.
> 
> Cost 1/10 the price of a SunDanzer too ... probably not quite as nice, but hey, it was that or no fridge!


Did you mean sundanzer or sunfrost?
Oh,and dont forget to tell use all about your solar system too.That would really help.Panels,batts and inverter,and does the thermostat(what brand) draw 120 power when the refer is off?

Lots of questions,sorry

Thanks,

BooBoo


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## frazzlehead (Aug 23, 2005)

The run down on the system:

PV Output Circuit (I have four panels, this is the info that is stuck to the inverter in the house):
Rated operating current 8.70A
Rated operating voltage 69.2V DC
Rated open circuit voltage 86.4V DC
Rated short circuit current 8.9A
Inverter :
Rated maximum operating current 29.30A
Rated maximum operating voltage 120V Ac, 60Hz

Battery:
Voltage 24V DC
four 6 Volt Surrettes 820 Amp Hour capacity


Basically, on a good sunny day I get 3.2 - 3.6 KwH (I live in Northern Alberta). The sytstem is rated for about 3.0 but we often get more than that. A good sunny day is about equal to my daily electrical load, but of course, we don't get those as often as one might like so I do run the genny every few days. Will be adding more panels and maybe wind as finances permit.


Fridge (freezer) is Kenmore deep freeze, yer basic sears model bought on sale for $300.

Fridge thermostat widget from Johnson Controls, ordered online for about $100 (my SH ordered it for me). 

Fridge just came on: meter reads 150W (initial surge, dropping down ... to 125ish), 1.3A
When fridge wasn't on, it read .01W which I think was just the ghost load from the killawatt meter itself. The Thermostat Widget appears entirely mechanical to my untrained eye. 

Will run it for a day and see how many KwH we use up ...


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## mightybooboo (Feb 10, 2004)

Ok,couple more questions,
Do you have a brand name on your inverter?
A part number on your thermostat?(too many at Johnson site to figure out what you use)
And finally,does your inverter go into sleep or standby mode,or is it always online?

Thanks Frazzlehead,

BooBoo


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## frazzlehead (Aug 23, 2005)

Inverter is always online (sleep mode wreaks havoc with my hot water heater etc). 

It's an Outback system, entirely (charge controller, inverter, everything).

I can get the info on the thermostat widget, but don't have it handy. I'll dig.


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## gccrook (Nov 21, 2003)

Don't know if this has been posted before, but look at thi bottom of the page at the Evaporation Pot-In-Pot System

http://www.selfsufficientish.com/fridge.htm


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## SolarGary (Sep 8, 2005)

Hi,



jnap31 said:


> So let me get this straight I am gettig confused If I buy this simple temperature controler and hook my ancient chest ferezer up and use it as a fridge keeping the temp. about 40 degrees I will be saving more money than if I use a regular upright fridge? or is this used in the energy eficient sun danzer freezers to turn them into refrigerators and save $. Please clarify I think I need to go back and re-read the other thread till I understand.


I know little about this, but I think that an regular chest freezer operated as a refrigerator (around 40F) will consume much less power than an upright refrigerator. Tom Chalko wrote a paper on converting a conventional chest freezer (Vestfrost SE255) a into to a refrigerator. He reports:

"Results of my experiment exceeded all my
expectations. My chest fridge consumes as much
energy in 24 hours as a 100W light bulb does in
just an hour. Not only it is energy efficient. I
have never seen a fridge that was SO quiet. It
only works 90 seconds or so every hour. At all
other times it is perfectly quiet and consumes no
power whatsoever. My wind/solar system
batteries and the power sensing inverter simply
love it. With my new chest fridge I have power
to spare and I can use it to warm up my house in
winter with a heat pump. I wonder why no one
has ever thought of a chest fridge controlled by a
digital thermostatâ¦"

You can find the whole writeup here:
http://www.builditsolar.com/Projects/Conservation/conservation.htm#Appliances

The 90 seconds run time per hour is kind of amazing.

He attributes the improvement to 1) the chest freezer design that does not lose its cold air every time you open the doors, and 2) the better insulation on freezers. I suspect it also has a bit to do with the size of chest freezers typically being smaller.

I think that if I were going to do this, and had to buy a new chest freezer, I'd look up which ones do best in the Energy Star ratings??

Gary
www.BuildItSolar.com


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## jnap31 (Sep 16, 2005)

mightybooboo said:


> No,it was to take a conventional chest freezer and turn it into a refer,supposedly saves a lot of juice over a chest refer.
> 
> BooBoo


But I guess it would not be good with mine as it is 30 years old, Probably would be better to do it with a 12 year or younger freezer huh?


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## Jim-mi (May 15, 2002)

Yes jnap you will be--in the long run--much better off "starting over". Lets face it, those old fridg's/ freezers just don't have the insulation needed to be efficient.
I hate to see it when somebody gets hung up over the *cheap* price of a new OR old unit. That $200$ unit from the big box shop is still "the bottom of the line"........they will need much more electric power to run that cheapie.
AGAIN--- adding those external thermostats only lets the compressor run less to get the 40+or- temp for it to be a *fridge*.
Pay now--or pay later..................


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## mightybooboo (Feb 10, 2004)

Jim-mi said:


> Yes jnap you will be--in the long run--much better off "starting over". Lets face it, those old fridg's/ freezers just don't have the insulation needed to be efficient.
> I hate to see it when somebody gets hung up over the *cheap* price of a new OR old unit. That $200$ unit from the big box shop is still "the bottom of the line"........they will need much more electric power to run that cheapie.
> AGAIN--- adding those external thermostats only lets the compressor run less to get the 40+or- temp for it to be a *fridge*.
> Pay now--or pay later..................


Jim,Im not sure thats totally correct about the cheapie using more.

My little Wood's freezer has a little teeny weeny compressor and doesnt dim the lights starting,seems very easy on the electric usage.Looks like a 1.3 liter engine vrs. an old 440 CI monster for an analogy.

I replaced lights with CF bulbs,added the freezer,and no change in electric bill.

I usually am running four to 6 lightbulbs,(2) 13 watters run 24/7 

Thats pretty darn good for usage.

Im thinking better built compressors are a good savings over those old monsters we used to have.

As always,the better built box will of course use less.

Replacing an old refer or freezer,with newer componets today is a good idea,even if it isnt the best of current,it probably beats the best of a lot of older tech.

BooBoo


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## frazzlehead (Aug 23, 2005)

Okay gang, we have the results 

The Kill-a-watt meter has been running on my fridge (see above: this is a Kenmore chest freezer, only a few months old, running with an external mechanical thermostat set at just below 40) ... it's been running for 32 hours and 12 minutes, and has used 0.39 kW.

That works out to 0.29 kW/day.


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## frazzlehead (Aug 23, 2005)

Oh yes, additional details: my fridge is sitting on a heated floor (in floor heating), although we aren't putting much heat through the floors this time of year. I will be insulating under the fridge when I put the actual flooring in place (I am in the midst of construction and have plywood floors - the hardwood is sitting in a pile in the corner, acclimating).

The compressor doesn't run very often, I hear it on occasion but it doesn't (subjectively) seem to be as frequently as the fridge in my old on-grid house.

Problems I have noticed are condensation inside the fridge, I have to wipe it down every so often as water drips down the walls inside and pools on the floor every so often, so I have to dry it off. I can live with that, considering that the cost I had calculated to get a SunFrost fridge to me was about 4K, and this cost me about $400. 

It's a bit weird, digging *down* in the fridge, and it is definitely smaller than my old fridge, but the Sunfrost would've been as well, so ... <shrug> it's working for me. I'm quite happy with it, actually, and would gladly recommend it to anyone.

A19AAT-2 is the number on the sticker on the end of my Johnson Controls thermostat widget, I presume it's a part number ... BooBoo does that help?


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## jnap31 (Sep 16, 2005)

Thanks for all the good ideas, I look forward to experimenting with them when I get home from here.


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## SolarGary (Sep 8, 2005)

frazzlehead said:


> Okay gang, we have the results
> 
> The Kill-a-watt meter has been running on my fridge (see above: this is a Kenmore chest freezer, only a few months old, running with an external mechanical thermostat set at just below 40) ... it's been running for 32 hours and 12 minutes, and has used 0.39 kW.
> 
> That works out to 0.29 kW/day.


Hi,
Good stuff.

Can you provide model number for the freezer, or the KWH per year off the EPA energy tag? It would be nice to know the savings from the value they have on the tag.

Maybe you could keep the Kill-A-Watt on it for a few more days, and report what you get?

Thanks,

Gary


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## Tango (Aug 19, 2002)

This seems more in line with what I've read regarding enegy star freezers with thermostats to run as refrigerators. Thanks Frazzlehead. But I am set on my Sundanzer and the clock is ticking. It will be small and run directly from the batteries. No new inverter for now, which I wouldn't be able to afford now anyway. Perhaps in a couple of years I can afford a Sundanzer freezer as well.


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## mightybooboo (Feb 10, 2004)

SolarGary said:


> Hi,
> Good stuff.
> 
> Can you provide model number for the freezer, or the KWH per year off the EPA energy tag? It would be nice to know the savings from the value they have on the tag.
> ...


Ditto,would appreciate the numbers and see how you number crunching experts interpret them.

Also,the size of the freezer.

Do you know the average amt. of power your inverter is putting out,avg. total watts,like 200 or 400/hr?

And the size of the inverter,I would like to try to figure out its efficiency rating at your normal output.

Yep,widget number will help,I should be able to figure model out from that.

Thanks frazzlehead for your effort.

BooBoo


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## frazzlehead (Aug 23, 2005)

Here's the info on the freezer: http://www.sears.ca/gp/product/B000...coding=UTF8&searsBrand=core&mqnodeid=16363801

It's a Kenmore 7.2 cu ft plain jane freezer, rated at 279 kWh/yr.

The KillAWatt has been running a few days now, and the math works out to 12.66 watts per hour. We are at 1 kW over 79 hours, at the moment. 


As for the inverter's details, I'll have to do some more digging. I 'outsourced' most of the research into my power system to my SweetHeart, who is the one who gets credit for the freezer-as-fridge solution, too. He found the custom built thermostat on builditsolar (thanks Gary!) and then went surfing to see if any such thing already existed, and found the kegerator plans. Solved the problem for me quite nicely! We even found a Canadian retailer of the thermostat widgets, and were able to save a bit that way on shipping/exchange/etc.

Tango, you could spend $400 on a fridge like mine, and take the rest of the money you'd spend on the Sundanzer and get more panels or a new inverter!


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## Jim-mi (May 15, 2002)

I would be curious to know what kind of inverter you would get for $400 ... ???
If Tango gets a SunDanzer, she will have a very high quality product that will last for a long time and will use less energy than your combo.

More often than not it pays (in the long run) to get the good stuff.


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## mightybooboo (Feb 10, 2004)

Great topic,thanks so much for the info.

BooBoo


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## jnap31 (Sep 16, 2005)

Jim-mi said:


> I would be curious to know what kind of inverter you would get for $400 ... ???
> If Tango gets a SunDanzer, she will have a very high quality product that will last for a long time and will use less energy than your combo.
> 
> More often than not it pays (in the long run) to get the good stuff.


Does not sound as though it will use much less though.


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## frazzlehead (Aug 23, 2005)

I've had great luck with my Kenmore appliances in the past and fully expect this one to live a long time.  

If you can afford the Sunfrost or Sundanzer, then enjoy! I suspect they deal with the moisture issues a little better, just cause they're doing what they're designed to do.

I am quite pleased with my little fridge solution though, if my SH hadn't come up with this solution I'd still be putting ice packs into the fridge at work and keeping my milk in a coleman cooler at home. 

Next I'm going to want an actual freezer that fits my electrical budget - for that, I'll probably have to spring for a proper one designed for running on solar!


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## Tango (Aug 19, 2002)

jnap31 said:


> Does not sound as though it will use much less though.


The Sundanzer fridge uses 100 - 300 watts a day. This fridge is using a little over 300 watts a day at present. It is interesting to track its usage based on ambient temperature. Frazzlehead, the $400 I save wouldn't buy the inverter to run it. The next inverter I need is priced at $1800 and can handle the starting surges and the additional appliances I'll have someday. I am very happy that you found a workable solution- it might have been my solution too had I been able to affordthe entire project.


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## Allan Mistler (Jun 1, 2004)

frazzlehead said:


> Next I'm going to want an actual freezer that fits my electrical budget - for that, I'll probably have to spring for a proper one designed for running on solar!


frazzlehead, I actually started this from the other side... I needed to protect my frozen foods from power outages and ended up running them full-time with solar generated power. It's because of my successful use of this system that I'm excited about replacing my current refrigerator with a chest freezer running at a lower temperature. I currently drive two 7 cuft GE freezers (cost each ~$200) from four Kyocera 125 Watt panels with a tracker and Magnum MS2812. The inverter was sized for my ultimate system (8 panels plus hydro generator) and loads which included my current refrigerator, furnace and well. If however I can drop the anticipated consumption from 2000 WHrs/day to 200 I'm all ears!!!
Anyway, those two freezers are full at the moment but their consumption appears to stay steady at about 750 watts (each) per day. The ambient temperature in our cellar (where they're located) is about 65 degrees. I currently utilize 6 (6 volt 120 AH) Golf Cart batteries and get almost three days of totally overcast weather out them dropping to 60% ROD before having to apply external charge source. The system is also providing for my cattle water-well (12 volt), fence charger and dog fencer so it's tough to isolate everything out to give specifics on merely the freezers.
This thread and the concept involved is valuable as is all the first hand experience being offered here.... Thanks so much for all your input! :dance:


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## mightybooboo (Feb 10, 2004)

Allan Mistler said:


> This thread and the concept involved is valuable as is all the first hand experience being offered here.... Thanks so much for all your input! :dance:


Absolutely,the first hand accts. are awesome.This is one of THE strong points of this forum,Im learning lots of good stuff.

BooBoo


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