Although photovoltaic panels are predominant, there are other options available to harness energy from the sun for home supply. So if you don’t want or can’t invest in cells or panels that increase the price of the installation, you can opt for a solar home system Peltier cells, generally designed to function as heat pumps. Do you want to know how to do it? We will tell you then.
Materials and tools required.
The essential materials to shape this system are as follows:
- Peltier cell.
- Fresnel lens.
- CPU cooler or similar heat sink.
- A 5V fan.
In addition, it is also important that you get thermal grease, black paint, foam, solder material, wire cutters, cardboard and reflective material.
1. Prepare the cell.
The first thing to keep in mind is that the objective will be nothing other than to achieve the maximum possible thermal conduction between the part of the Peltier which is not hot and the refrigerator. Thus, he begins by freeing the refrigerator from any room that he can incorporate. If you have a fan and thermal substances, remove those as well. Once you have completely emptied the refrigerator, clean it well with alcohol and dry it with paper.
He then places the cell on a newspaper page and applies the black paint to one of his faces. The next step will be to coat the cell with thermal fat, without overdoing it.
You will now have to decide where in the refrigerator you are going to place the cell and, when you do, glue the two parts. If you can’t decide, placing it in the center will be a good option.
2. Fit the parts well.
In this step, you will need to make sure that the cell is properly adjusted. For this, you can use wire or any other material, which, of course, must have high resistance to high temperatures.
Then you will need to repair the fan, for which you can follow the same model as in the pictures. In this case, it was secured with small rubber bands at the base and around the fan. In addition, it was chosen to incorporate a piece of cardboard to prevent the blades from hitting the cooling system.
3. Create the framework for your system.
Before you start working on the frame, a good option is to cover the cell with foam and place it at the bottom of the cooling system. Remember that it will be necessary to drill holes for the lead wires, among other things. Since it is not possible to apply glue on this type of cell, in this case we have opted again for rubbers.
At this point we will have to start working on the chassis that will contain the equipment. In these pictures you can find the inspiration to create it, because the possibilities are so many. What will not change, whatever system you choose, will be the need to estimate the measurement between cell and lens for the focal point, so that the distance can be adjustable.
Try not to measure the focal area where the light is at its smallest point. Dig around the lens until you aim for the spot that creates a square shaped point. At this point, measure only in the area where the dot is slightly smaller than the size of the Peltier.
Then cut the frame. In this example, a slit has been created to facilitate back-and-forth movements to better adjust the focal length. When putting this structure together, remember that it is essential that the cooling system does not receive more heat than it is already picking up from the Peltier. Otherwise, your home equipment will waste a lot of the energy it captures.
4. Final details.
To complete this system, it is practical to equip it with a reflective cover. To do this, cut four pieces of foam a little longer than the Peltier, but half the width. Once you have them, glue them as you can see in the picture, if possible with double-sided aluminum foil incorporated, like those from a bag of chips. Also, if you want to gain extra power for the fan, you can add a small 3v 150mA solar panel to the system, which will provide enough power to power this part of the equipment.
With this you will have finished building your solar panel with Peltier cell, which can be done for a cost of less than 20 euros. The system registers a voltage of up to 2.7 V as long as it is the correct size and pointed towards the sun. To increase power, improvements can be applied, such as providing the equipment with a solar tracking system, among other ideas that can improve its performance.
Original project in Instructables.