This article shows that you can save energy by converting an old freezer into a refrigerator. The result is a refrigerator that is more economical than the most efficient A + + refrigerator (This is an indication of the most efficient appliances on a European efficiency scale).
Due to circumstances, we had a freezer available for which we had no more direct application. Selling in a yardsale, of course, was an option, but usually that doesn’t generate much money (perhaps therefore a good idea to buy a freezer yourself in this way). As a freezer has significantly better insulation than a refrigerator and we have a 2nd refrigerator in use, it seemed like a fun experiment to me, to convert the freezer into a refrigerator and see what this meant in relation to energy use.
Indeed strange, that if you think about it, the temperature difference over the wall of a refrigerator about 15°C (59 °F) is equal to the temperature difference over the wall of a house. Outside heating season average of 5°C (41°F) in Holland and inside 20°C (68°F) while the walls of houses today have a proper insulation thickness. I do not know what the building regulations require nowadays, but my guess is, that it will be a minimum of 6-8 cm (2.4-3.2 inch) or more?. While a refrigerator often has to operate with only 2 cm (0.8 inch)!
Well as said, as done. A Miele brand freezer of approximately 250 liter (66 gallon) was the starting point. Electronics (thermostat, alarm, digital thermometer display, etc) were removed. The electronic temperature sensor could easily be pulled out at the back of the cabinet, after the removal of a plug. This has been done, in such a way, that I can convert it back, so that (if necessary) also the freezer can be used again as such. An electronic thermostat from a kit of Conrad (part# 19 48 83, at € 14, -) was built. Of course, a type was chosen, suitable for the temperature of a refrigerator at least for the range of 0-15°C (32-59°F). The thermostat was built and connected to the relay in the live wire to the compressor (as, of course, was already the case in the original thermostat).
The first measurements
After switching on, the thermostat was set at 5°C (41°F) and the energy consumption was measured with one of those handy “in between” meters (Energy Check 3000 at € 20, -) also offered by Conrad.
The measurements were conducted over 4 days. Converted to an annual consumption, it was 47 kWh!
By comparison, some energy consumptions (per year) of new refrigerators with similar volume follow hereafter.
The energy consumption numbers below are taken from the Dutch review website www.kieskeurig.nl.
- A + +: no refrigerator of that volume found, but one with about 350 liter (92.5 gallon) had a consumption of 105 kWh / year
- A +: 120-140 kWh
- A: 160-170 kWh
- B: 240 kWh
We had an old (2nd) refrigerator with a capacity of 200 liter (52.8 gallon) in use, with an annual consumption of about 225 kWh. Thus now we have a saving of 178 kWh/year. At an average kWh price (high/low rate) of € 0.21 it means savings of around € 37, – / year. The savings compared to an average Dutch household consumption of 3500 kWh per year is with 178 kWh / year about 5.1%. That is (in terms of electricity consumption) already almost the 6% Kyoto target!
Condensation of moisture
Are there any disadvantages? Yes, there is no drain available for the condensed moisture. There is therefore an occasional drop of water on the goods in the refrigerator.
After this experiment I’m asking myself whether it would be difficult for the European Commission (with a number of stringent environmental objectives), to just impose rules for future refrigerators to be sold in the European Union. For example, one could imagine that from 2015 on, only refrigerators with energy label A ++++ are allowed to be sold. Besides refrigerators of course rules can be imposed, for many more types of devices imposing a certain maximum consumption.