Modify your old fridge and buildt your own eco fridge

If anybody plans to insulate his old or even new fridge to save some energy and money here are some thoughts:

  1. Condenser and evaporator of the fridge have to stay clear and not covered by insulation! One has to find out where they are (see How a fridge is built). The condenser is giving away the heat so it has to be on the fridge's outside, often its at the back of the fridge. But careful: some fridges got it integrated into the sidewalls, you would be able to feel it, cause while the compressor is running its getting warm. The fridge's evaporator is inside. At older fridges they are often visible like in my fridge at the upper right corner. Modern fridges can make it more difficult, cause they often integrate it into an inner wall. That is where the cold is coming from when the fridge is running. Dont insulate that part of the fridge. To make it more complicated fridges with integrated freezers often have heating elements inside the inner walls (sounds stupid but for technical reasons its necessary), they must not be insulated neither. If you are unsure add insulation only to the exterior where you can easily identify the condensor.
  2. Effort. My eco fridge insulation project took maybe 20 hours, which was a pleasure to me. If you dont like to spend so much time you can save the biggest amount of energy by just insulating the large outer walls and top of the fridge. All that was fast done and it maybe does not even need decorative measurements cause its often not visible anyway.
  3. Condense water. Theoretically condense water could accumulate under the polysterene insulation of the self-made eco fridge. But after 2 years running there are no signs of it. I believe that the original fridge walls dont get cold enough for condense water to accumulate. To be sure i was putting the glue on all the edges of the styrofoam so no air can get between them and the fridge itself. 
  4. Hygiene. Fridge surfaces should be easy to clean. Styrofoam itself is often s not easy to clean because of its rugged surface. A solution could be to buy insulation material with a smooth surface that can be washed or use that decorative foil i die use (see Insulating fridge). Or again, just stick to the outer walls, which are less critical what matters to hygiene.
  5. Alternative methods to fix the insulation. Because my eco fridge is made of an old fridge and there is no warranty anymore i did glue the insulation polysterene directly to the fridge's wall. If you want to keep your fridge's warranty rights or for transport reasons it might be useful to be able to remove the insulation from the fridge. I did hear about using magnets inside the polysterene or building a frame around the old fridge which keeps the insulation at place. What i dont know is whether in these case condense water would develop between fride and insulation.
  6. Ventilator. One could use a ventilator to get the heat away from the fridge'scondenser. It could be running at the same time as the compressor. I got the feeling that this does not save much energy.

Changing a freezer into a super eco fridge

Even the most ecological fridges (A++) on the market are only reaching 90kWh per year power consumption. That is not enough for a fridge in my opinion knowing that some ecological energy efficient freezers with minus 18°C inside only need 130kWh per year. I am dreaming of the following project: putting a fridge's thermostat into one of these well insulated energy efficient eco freezers and therewith building my super green eco fridge. I calculated that the fridge's power consumption would be around 30-40kWh per year at 25°C room temperature.

Now i found somebody describing the changing of a chest freezer into a super eco chest fridge reaching 36,5kWh a year:

How a fridge is built

technical configuration of a fridge

A: outside the fridge
B: inside the fridge
I:  fridge's insulation

1: Condenser
2: Expansion valve
3: Evaporator
4: Compressor

And the insulation is the part of the fridge where one can add some. Here are the steps i took: Insulating the fridge