Not so long ago, and even today, a refrigerator in car can be considered a luxury. But this is a pretty useful thing. Here you can put ice cream, sparkling water, transport any frozen food and much more. The store will require a considerable amount for such a device, so it makes sense to collect a car refrigerator do it yourself. In addition, it is interesting, simple and several times cheaper. You can also make a refrigerator of any shape and size so that it fits comfortably in a place prepared in the car. According to the author, the cost of such homemade is within 1000 rubles.
A Peltier element is used as a cooling element (this is a plate that, when voltage is applied to it, heats up on one side and cools down on the other). You will also need one or more (depending on the size of the refrigerator) computer coolers with radiators. You can get them for free if there are unnecessary computers.
Materials and tools for homemade:
- extruded polystyrene foam;
- ruler;
- pen, felt-tip pen or other writing instrument;
- stationery knife;
- Peltier elements (you can buy, are not expensive);
- computer coolers with radiators;
- polyurethane foam;
- a wire with a cigarette lighter connector;
- a board of a temperature regulator;
- soldering iron, scissors and more.
Refrigerator manufacturing process:
Step one. Container manufacturing
In general, the author originally wanted to make a thermos container that would keep the cold inside. That is, for transportation over short distances of chilled products. But then the container turned into a full refrigerator.
A container of expanded polystyrene is assembled, mounting foam is used as glue. This is good because the foam hermetically seals all the cracks. The most important thing in the design process is good thermal insulation; the better the cold stays, the more efficient and economical the refrigerator will work.
You can choose any sizes for your needs, the author for the assembly was enough a sheet of polystyrene foam with dimensions of 1200x600 mm and a thickness of 50 mm. The sheet is simply cut according to the template, and then glued into the treasured box using polyurethane foam.
In the picture you can see the scheme for cutting the sheet, if there is a desire to assemble exactly such a refrigerator. On the sheet there are sides, the thickness of which is 20 mm, they need to be cut from all sides, leaving the bottom.
For bonding, the foam is applied and waiting 1 minute, then you need to press the parts for 5 minutes and make sure that they do not move. As a result, only a small piece of polystyrene foam will be superfluous, it is marked in gray on the diagram.
After the box is ready, it can be painted. You need to paint in two steps, since the paint can corrode polystyrene foam. However, it is advisable to choose the right paint for these purposes. The container weighs 820 grams; frozen foods lie in it for quite some time.
Step Two Installing a cooling element
To make a full-fledged refrigerator, you need a cooling element, here it is electric - this is a Peltier element. The peculiarity of this device is that when voltage is applied to it, then one side of it becomes very cold, and the other heats up. So, so that the Peltier element does not burn out, heat must be removed from its hot side. The cooler from a computer with a radiator, which cools the processor, copes with this task perfectly.
The most powerful Peltier element will cost about 130-150 rubles (power 60 W).
To prevent the radiator from freezing on the inside and cooling the air evenly, it was also decided to install a cooler on the inside of the refrigerator. For the system to work autonomously, you will need a temperature controller with an external sensor, its cost is in the range of 170 rubles.
Now the degree of cold in the refrigerator will control electronicsIt will also reduce energy loss.
The author installs the Peltier element between two radiators, thermal paste is used for better heat transfer. As a result, one radiator will cool one side of the element, and the other radiator will be located inside the refrigerator and distribute cold over it. One such element is enough to keep the temperature inside the refrigerator at -3 degrees at an ambient temperature of +26. If you install 2-3 such elements in series, then theoretically the temperature in the refrigerator can be reduced to -18 degrees.
Radiators are interconnected using standard brackets, with which they are attached to the motherboard. Still need plastic clamps. The greatest efficiency was achieved when both fans worked on blowing from the side of the radiator.
As thermal insulation, pieces of thermal insulation for round pipes were used.
Step Three Assembly assembly
A hole must be made in the refrigerator lid to install the cooler. The shape of the hole should be the same as in the photo. Then the seams are smeared with sealant and a design of radiators is installed. It’s important not to mix up where the cold side is and where the hot side is. The cover can be pre-painted, while the rigidity of expanded polystyrene increases.
Next, on the cover, you need to install a thermostat and connect it to the manufactured device.
If we talk about numbers, then as a result, at an ambient temperature of +29 degrees, the temperature of +5 degrees is kept at the bottom of the refrigerator without problems. As for consumption, the current consumption is about 3 amperes. According to the author, this is an excellent result.