off grid refrigeration

[j.steele]

Hi.... keen to hear your thoughts on refrigeration for an off grid situation. I have been rather alarmed at the cost of "solar" fridges. They retail for anywhere between $1200-$2000. I am curious as to what others are doing. My initial plan was to buy an "normal" energy rated fridge and run that on a timer for maybe 4- 6 hours during the day when the chances are it can run straight off the panels. In the evening, the fridge would be off. It's got me thinking though whether this would be false economy, as maybe it would take more energy to cool it down again the following morning than it would to mainatain a constant low temp overnight - a bit like the fluro light scenario...... Any thoughts?

this is probably not the right place for this, but has anyone had experience with evaporation coolers..... thinking "mitticool" or some home made coolers? Cheers.

[almac]

Hi.... keen to hear your thoughts on refrigeration for an off grid situation. I have been rather alarmed at the cost of "solar" fridges. They retail for anywhere between $1200-$2000. I am curious as to what others are doing. My initial plan was to buy an "normal" energy rated fridge and run that on a timer for maybe 4- 6 hours during the day when the chances are it can run straight off the panels. In the evening, the fridge would be off. It's got me thinking though whether this would be false economy, as maybe it would take more energy to cool it down again the following morning than it would to mainatain a constant low temp overnight - a bit like the fluro light scenario...... Any thoughts?

this is probably not the right place for this, but has anyone had experience with evaporation coolers..... thinking "mitticool" or some home made coolers? Cheers.

think its just one appliance that is too power hungry. gas fridge i think is the way to go.

[Mike90250]

My feeling is to use a standard Energy Star rated fridge. They consume "about" 1Kwh of power a day, and my 2, 20CF fridges have plenty of room. The "solar" fridges are often just 7-10CF.

The drawback is, they expect Hover Dam on the end of the cord, and have a hefty starting surge, which means most 300 or 400 w inverters do not have enough capacity to start the fridge. Most of the 1,000w inverters are able to start the fridge.

[j.steele]

think its just one appliance that is too power hungry. gas fridge i think is the way to go.

Thanks.

Hmmm.....thought about gas, but when you do the sums gas fridges are very expensive to run, is it better to put that investment into batteries that become an asset rather than LPG which isn't? Not to mention I am nervous about the open flame and CO gas.( maybe unrealisticaly so though...)

[Wakie]

I own a samsung fridge with a variable speed compressor, it draw only 70 -90 watt when running
22 cubic feet 440 kwh /year probably less if the ice maker is not used
The compressor start slow, and increase in speed if needed
I have nothing to mesure the surge power

[j.steele]

My feeling is to use a standard Energy Star rated fridge. They consume "about" 1Kwh of power a day, and my 2, 20CF fridges have plenty of room. The "solar" fridges are often just 7-10CF.

The drawback is, they expect Hover Dam on the end of the cord, and have a hefty starting surge, which means most 300 or 400 w inverters do not have enough capacity to start the fridge. Most of the 1,000w inverters are able to start the fridge.

Cheers.... with the battery bank I am proposing I would get approx 10kwh or 5kwh at 50% DOD, which means powering the lights, Dc waterpump and the odd low draw appliance like a laptop, 5kwh would give me approx 5 days autonomy. If I throw in a 1kwh load from a fridge into the scenario, my autonomy will drop to maybe 3 at best.... So would setting it up on timer to run for part of the day mean false economy in your opinion?

[Bala]

I have a Vestfrost fridge, well I have 2 fridges and a freezer. The first fridge had a thermostat problem and could not be fixed so they sent me a new one, I still have the old one in the shed. The freezer stopped cooling properly at about 2 years, if I was more on the ball I would have got it replaced as well. Dealer was thousands of miles away.

They are a eutectic system, deemed to be very energy efficient. They use R600 gas which is isobutane and operates at lower pressures that older gasses. So energy is saved as compressor is not working as hard.

When i bought them and the freezer had problems I could only find one service person in the state who had some r600 and had had not opened it. It is highly flammable and there was issues with safe use.

I just went and bought a westinghouse common freezer, they are 1/3 the price of the vestfrost style and using R600 gas now as well.

If I was to buy a new fridge now I would just look for the most economic domestic model that suited.

With off grid your shopping for appliances that will run at night, or a lot, is based on current draw, not price.

I have put my watt meter on both.

The freezer has start up of approx 1100w and run of 75w. It is a few years old so I would expect fridges now to be at least that or better.

The fridge shows a start up of 245w, with a run of about 220W.

The freezer cycles a lot more than the fridge.

As Mike said, if you looked at 1KWH a day for the unit, in your climate I think you will be well covered.

[Amy@altE]

What some people also do is get an EnergyStar chest freezer and replace the thermostat to be more refrigeration temperatures. The chest freezers are better insulated, and use much less power, and when you open the lid you don't lose all of the cold running out of the door. The down side is that you have a chest fridge, which can be a pain in the neck. My hubby did this for his kegerator (he calls it a kreezer), I had a Kill A Watt meter on it, it barely used any power to keep it at 38F.

I just searched for an old post where we were talking about this, someone who did it said they had a 8cu converter ffreezer that used 500Wh a day.

[paulcheung]

I have 1 freezer and 1 refrigerator, I use timer on both of them doing time shift. the timer turn on the freezer at 8AM and turn it off at 4PM each day, it also turn it on at 9pm and off by 10pm. I have 4 baskets in the freezer that come with the unit when I bought it. I have 4 bags solid ice on top of the baskets 1 each to keep the temperature down during the off time.

The refrigerator turn on at 8am and off by 8pm, then turn at 11pm and off at 12 midnight, it turn on again at 4am and off 5am. I don't have any problem just can't keep fresh milk in the refrigerator too long.

[thastinger]

I converted a 7.2CuFt chest freezer to act as a fridge. It uses .5Kwh/day at 33 degrees and me opening it 30 times a day. Use this to "convert" it. http://www.amazon.com/Johnson-Contro...ture+controler
The freezer is actually unaltered and can be returned to freezer duty anytime by unplugging from the Johnson controls module and plugging directly into the outlet.

[j.steele]

Fantastic..thanks! Great to see the different ways people deal with this challenge. I am intrigued with the conversion of a chest freezer to a fridge, I will look into this. I can imagine it would be a tad onerous to access stuff inside, but given the fridge is for a cabin, then I think we can handle that for a few days at a time. Thanks guys.

[Bala]

Fantastic..thanks! Great to see the different ways people deal with this challenge. I am intrigued with the conversion of a chest freezer to a fridge, I will look into this. I can imagine it would be a tad onerous to access stuff inside, but given the fridge is for a cabin, then I think we can handle that for a few days at a time. Thanks guys.

I think the freezer conversion is common, if you google I am pretty sure you can buy kits online.

As Amy said, they appear to work well energy wise just not very convenient to use.

[bberry]

I wonder if freezing a lot of water during the day (in a top freezer unit) would help cool the bottom frig portion at night on a powered off unit? This would be a modern version of the ice box.

[thastinger]

I think the freezer conversion is common, if you google I am pretty sure you can buy kits online.

As Amy said, they appear to work well energy wise just not very convenient to use.

There's no "kit" or conversion needed. Just buy what I linked to earlier and it'll work fine.