Refrigeration using solar power

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

Modern fridges and freezers use relatively little power; somewhere between 150 and 400W. And the total energy consumption is around 1 to 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, your 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. 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.

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 a 50kg bag of wheat berries every year 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.

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 another set of 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 an third 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 from solar power, it's worth spending the extra and a fridge for example that uses inverter technology.

There are three reasons that I can think of:

  1. Inverter fridges and airconditioning 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 cooking.

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 could do it, so could you.

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

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 green food every day.

Low GI bread

Low GI bread too can be cooked using a breadmachine powered by solar; I alluded above to the fact that we keep wheat berries in the outside fridge.

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.

Heating during the day and refrigeration using solar has so many applications in the home.


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.

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.

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

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.

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.

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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.

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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What's this site about?

Bernard Preston books

A family affair by Bernard Preston

Consulting a chiropractor

Femoral nerve AP Xray

Bernie's healthy choice foods

Cooking green beans Bernard Preston passion

Bernie's bread

Bread machine loaf by Bernard Preston

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green beans and granadillas Bernard Preston

Bernie's bees

Bees workforce in Bernard Preston's garden

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Residential solar panels at Bernard Preston's home

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View from Bernard Preston's glider