Permaculturing in Portugal

One family's attempts to live in a more planet-friendly way


I had been thinking for some time on how to tackle the issue of refrigeration on the quinta. An early experiment hadn’t been encouraging. It’s all very well using a zeer pot for a few items (I have one in the yurt made from 2 large plant pots), but when there’s volunteers or guests staying, it’s a lot less practical. I found myself torn between the desire the keep it low tech and cool things naturally, and having the convenience of somewhere I could easily store more sensitive foods like meat and even indulge in the occasional ice cream. I don’t eat a lot of meat, but I have two cats and a dog who do. With the price of pet food rising while the quality plummets, I’d also been thinking about making my own animal food. This would be a lot more tricky without a fridge.

Zeer pot used for refrigeration in the yurt

Both solar systems generate more than enough electricity to run refrigeration in summer, which is when it’s most needed, so I decided eventually to buy two small chest freezers. Rated A++, they were the most energy-efficient I could get for their size. I bought freezers rather than fridges for two main reasons. Firstly, the fact that they’re freezers allows me the flexibility to run them either as freezers or fridges according to need. Second, because they’re top opening, the cold air remains inside when you open them and they consequently make far more efficient use of power.

For this summer, one has been run as a fridge at the wee house, and the other as a freezer at the main building. It’s been very successful, made life much easier and resulted in far less wasted food.

Small chest freezer being run as a fridge on a timer

There are many resources on the internet showing how to convert a freezer to a fridge by replacing the thermostat. When I was first thinking about the idea of using chest freezers, this seemed like the best approach, but a local friend recommended using a timer instead and simply adjusting it with ambient temperature to maintain the optimum internal temperature. After some initial misgivings, I realised this was the better idea since it allowed me the flexibility to still use the unit as a freezer, was far less hassle to implement, and the timer could be set to operate in daylight hours only to put even less demand on the batteries.

Timer for the small chest freezer being run as a fridge

Internal temperatures do fluctuate more with this method, at least with the timer I’m using. The minimum amount of time it’s possible to set an appliance to come on for is 15 minutes. Since the freezer thermostat is set for sub-zero temperatures, when the unit comes on it runs for the entire 15 minutes and in that time takes internal temperatures to below freezing point. However, it’s a short-lived effect – not long enough to freeze anything in the cabinet – and the temperature slowly comes up again in the meantime.

With ambient temperatures (Celsius) in the teens to low 20s, 4 cycles of 15 minutes every 24 hours were sufficient. High 20s and 30s, it went up to 6 cycles. We didn’t really hit the 40s this summer.

We did, however, make and eat a lot of ice cream!

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  1. michelle November 16, 2014

    ….and the ice cream was :) sublime

  2. Sandra Storr December 9, 2014

    We’ve successfully used a thermocouple from a home brewing shop in order to use a chest freezer as a fridge. Keeps the internal temperature constant without freezing and you are not altering the freezer itself so can continue to use it as a freezer as and when required. We used a kil-a-watt meter to check consumption and it used 100W in a 24 hour period, so don’t know if that compares favourably with your timer method? Just wondering whether pressure canning of the pet food might work for you also?

  3. Quinta do Vale December 9, 2014

    Interesting! I’ve no idea what the power consumption of the timer method runs out at as I’ve no means of measuring it but I like the idea of the thermocouple. Less variation of internal temperatures has to equate to better food storage conditions. Thanks for that! Will investigate further. My mother was terrified of pressure cookers and I don’t think I’ve ever encountered one in use, far less used one myself, and know nothing about that whole area of preservation. It seems like it would be a lot of effort for such short term preservation? The pet food I make is used within a week.

  4. Johnathan December 10, 2015

    Have you ever considered a solar fridge/freezer? Just taking one of them off grid requires 1 panel and 2 batteries. Even easier if you already have an existing solar setup. If you’re not familiar with the subject, you can check it out here:

  5. Quinta do Vale December 10, 2015 — Post author

    No I haven’t, and at those prices I can confidently say I never will! Good grief!! I can’t even get my head round the kind of logic that could justify paying that kind of money for a DC unit when a decent inverter can be had for half the price!

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