The Peltier jacket is a jacket that can heat you up when you are cold or cool you down when you’re too hot. It basically keeps you at a comfortable constant temperature. The jacket achieves this with 8 modified Peltier cells and temperature sensor that tell the cells if whether they should cool or heat the users.
These cells consist of two copper plates that have a Peltier element and some insulating material in between. The Peltier element is an electronic device that can create a temperature difference when current is applied to it. The copper plates help to spread out the heat and the insulator prevents heat moving to the cool side.
The Peltier element
The Peltier element carries heat from one side to the other when current goes through it. This is called the “Peltier effect”. When the direction of the current is reversed the heat flow is also reversed. This way the jacket can change the temperature. The Peltier effect can be reversed. When there is a temperature difference across the element voltage is generated across the positive and the negative pins. This is called the “Seabeck effect”. In theory the Seabeck effect could be used to charge the jacket if needed.
The jacket is powered by 12 volt power supply that is connected to the power grid. When active the circuit draws about 4 amps.The jacket is controlled by an arduino micro. There are two h-bridges because the arduino can’t handle 12 volts. The h-bridges get a signal from the micro controller and let current pass through were needed. The h-bridges are screwed to a heat sink to prevent them from overheating from the current and also to hold them and the arduino in place. The Peltier cells are connected to the output pins of the h-bridge in 4 pairs. In each pair the cells are connected in series.