Concentrated solution of ammonia is heated up to avaporous state in a tank. Under high pressure, this gasenters a condenser where it is liquefied. There it is supplied with hydrogen, which causes the liquid ammonia to evaporate. At the same time heat is extracted from the cooler’s interior. The ammonia gas then enters the absorber, where it is taken up by a weak ammonia solution. The saturated ammonia solution flows back to the tank, and the cycle starts again.
Compressor devices are running with the help of a refrigerant. This cooling agent changes from the liquid to the gaseous state inside the evaporator. At the same time the evaporator binds the warmth from the interior of the cooling device – it’s getting cold. The compressor draws in the gaseous refrigerant, compresses it and passes it on to the condenser, where the binded heat is released again. The refrigerant changes to the original liquid state once more and flows back to the evaporator, where the cycle starts again.
The thermoelectric principle was first discovered in 1834 by J.C.A. Peltier – that’s why the temperature producing parts of thermoelectric systems are described as Peltier elements. It is based on the fact that – depending from the polarity – cold or heat is generated when a direct current (DC) flows through a junction of two dissimilar metals. This cooling or heating power is still increased by heat exchangers and fans. It is sufficient for small and medium-sized coolers.