Refrigeration using solar power

Refrigeration using solar power is a breeze for even a small inverter.

This page was last updated by Bernard Preston on 12th April, 2019.

Solar lens effect

Modern fridges and freezers use relatively little power; somewhere between 150 and 400W. And the total energy consumption is between 1 and 2 kilowatt hours per day.

Since most of this energy is used during the day when it's hot, there's a perfect synergy with solar power. 

My first inverter was rated at 2kW and, being a novice, I was astonished that it would power a fridge and separate freezer when the grid in our area collapsed for 36 hours; they were full of goodies just before Christmas.

Even if you plan to go off the grid, which I do not recommend incidentally, adequate batteries will handle the cooling at night with relative ease except perhaps in a very hot climate.

Often the decision to toss an old fridge or freezer is not because it no longer works, but because the seals start to deteriorate and it begins to run all day consuming large amounts of electricity. The compressors usually last for years before they fail.

Instead of tossing that old fridge, put it rather in the garage and run it only on solar during the day. Keep items in it that need to be cool, but it matters not if they thaw during the night; cold drinks and beers, for example.

Going off the grid

We have had second thoughts about our aversion to going off the grid since a power surge from the utility caused immense damage in our street; that's double the normal voltage; 220 V in South Africa.

Power surge producing 431 V instead of 220 V is giving us thoughts of using solar power exclusively.

Refrigeration using solar power

Refrigeration using solar power is very efficient as cooling is needed mostly during the day.

This is particularly true for green freaks who have a lot of stored organic foodstuffs. For example, we purchase three 50kg bag of wheat berries every year from a farmer for baking our own bread. It needs to be cooled or frozen, otherwise the beetles take over.

You'll never find them in white flour by the way; beetles know the difference between junk food and the real McCoy. Wheat berries have all the goodies in the kernel that we need for vitamins and minerals, and phytosterols such as lignans. They are typically all removed during the refining process and fed to the pigs. We are left with the crap!

Then it's always useful to have a couple extra ice trays should friends and family suddenly descend on you unexpectedly.

We also keep our tahini in the fridge; it's easier to purchase half a dozen bottles at a time because you have to find a Greek or Lebanese shop. It's good stuff by the way, and much nicer than peanut butter to my mind. We use it for making our quick hummus that turns even the dullest salad into a delight.

Then because I'm the bar wench at the gliding club, all the surplus drinks are kept in that outside refrigerator in readiness for next Saturday.

In short, refrigeration using solar power, and air conditioning too, is a breeze for your inverter; if you have enough PV panels. It reduces the payback time of your setup and we find it very useful having a second old freezer that costs nothing to run during the day.


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On the subject of inverters and PV panels, don't make the mistake I made by putting in a Mickey Mouse system. It does nothing for the environmental freaks if you produce only 2kWh of sunshine energy per day, and it will stress you out.

My strong advice is to go straight to at least a 60 amp regulator and 5kWh inverter using a 48V system. You will end up upgrading to this eventually so do it right from the beginning; then it hurts only once.

You can add more PV panels later, and extra batteries, should you want them, but to upgrade the inverter and regulator after a year is a serious waste of time and money; do it right from the start.

A 48V regulator is so much more efficient. High voltage means low amperage with much less loss of power in the cabling; you can use thinner wires too, saving you more of the setup costs.

If you are serious about going solar, and you have the money, then go straight to a 10kW inverter; that's what I now have and we can run the dishwasher, the oven, the lawnmower and my power tools without a problem during the day.

It's such a pleasure using only $5 of electricity per month from the utility; payback time is five to ten years. The best is pure sinewave energy with no dips and surges to burn your electronics.

The best regulator incidentally is called a solar charge controller MPPT; it extracts about a third more from the panels. They cost around an extra eighty bucks; in the long term it's definitely worth it.

But stay on the grid for the inclement weather.

Inverter technology

When purchasing units requiring refrigeration using solar power, it's worth spending the extra and one that uses inverter technology.

There are three reasons that I can think of:

  1. Inverter fridges and air-conditioning units use about 30% less electricity.
  2. Normal electric motors require a heavy current to start up; that means you need a much larger inverter.
  3. They are much quieter.

Fridges using inverter technology have variable speed motors; that means if there is a small drop in temperature, the compressor doesn't need to work at peak capacity saving electricity.

The compressor never switches off but runs at a very low speed, making far less noise.

Freezing chickpeas

Freezing chickpeas is the solution if you enjoy hummus; there are several distinct disadvantages from using the canned variety and they take long hours of conventional cooking. Store them with refrigeration using solar power.

It makes sense to pressure-cook a large amount, say a couple pounds, and then drain, cool and freeze them in small packets.

I like to use recycled food grade plastic packets incidentally; our world will soon be suffocated by non biodegradable synthetics.

Then freezing chickpeas is a breeze; even more so if you have refrigeration using solar power.

They're known as garbanzo beans, by the way, in some parts of the world.

I'm sure you've noticed the commitment to permaculture here. Using a pressure cooker saves time, energy and money. Enjoying freezing chickpeas reduces our dependence on cans. Recycling plastic packets is protecting the environment, and Mr Golden Sun provides the power to cook and chill the garbanzo beans; hummus is one of the world's healthiest foods.

Wean off plastic if you want your grandchildren to have a habitable world. Capturing solar power energy is another very significant step in protecting our environment; if Bernard Preston can do it, so could you.

Then you can run all your appliances like refrigeration using solar power.

Using frozen chickpeas it takes me only five minutes to throw together our authentic hummus recipe; you will need to find a source of tahini. It will turn even the most boring salad into a delight for the tongue, and happiness for the colon. If you want to avoid colorectal cancer make sure you are enjoying organic food green every day.

Low GI bread

Bread machine loaf baked using solar power is dependent on refrigeration to keep the wheat berries from bugs and moisture.

Low GI bread too can be cooked using a breadmachine powered by solar; I alluded above to the fact that we store wheat berries for a whole year by refrigeration using solar power.

Including grinding the wheat to make healthy flour, it takes me only five minutes to prepare the goodies for our low GI bread. No chemicals, half the salt and a wonderful mixture of ground seeds give this loaf a divine flavour.

Baking and cooking during the day when the sun's energy is pouring in, and refrigeration using solar power, has so many applications in the home.

Healthy flour is dependent on having a wheat mill.


Tahini is a wonderful paste made from sesame. Like all nuts and seeds, once the shell is cracked it starts to go rancid very quickly; our solution is refrigeration using solar power.

Nuts should be eaten freshly cracked, or vacuum packed, and seeds kept cold; refrigeration using solar power is perfect for keeping goodies like these cool.

This tahini paste can be found in Greek and Lebanese shops; we enjoy it too on our low GI bread to mop up salad juices; the taste is heavenly.

Tahini and the benefits of freezing chickpeas is one of the many discovering Bernard Preston discovered whilst living in the Netherlands for seven years. Have you read Stones in my Clog? Ebooks are dirt cheap.

Then it goes into our quick hummus and baba ghanoush; that's a side dish made from eggplant.

Holland is also where he got the inspiration for using solar power. Refrigeration is just one of the many blessings brought by Mr Golden Sun, as his grandchildren call him.

Useful links

  1. Bernard Preston
  2. Solar power energy
  3. Refrigeration using solar power

Bernard Preston

Bernard Preston is a physics major who went on to study chiropractic. After thirty-five years he is now semi retired and potters in his organic garden, with his solar generator and flies gliders over the weekend; refrigeration using solar power is just one small benefit of going green. 

Live life at full speed is his motto, foot flat on the accelerator and expect to drop dead in harness with all your marbles intact. No old age home and dementia for him.

Refrigeration using solar power is just one of his little interests. The aircon energised during the day by the sun is his next chore.

He's something of a green freak with organically grown fresh vegetables and fruits, huge compost heaps, worm farms and their own free ranging hens are all a part of their home.

Then he's a writer of some note; you might enjoy one of his chiropractic books like Bats in my Belfry. He's busy with his seventh; called Priests Denied it's going to be controversial.

See the index, they are dirt cheap on Kindle.

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56 Groenekloof Rd,

Hilton, KZN

South Africa