Compressed air is still a valid helper in many applications today, where it is necessary, for example, to move work equipment, pistons or it is used for cooling as a cooling medium. The producer of compressed air are air compressors, which need an external source for its production, usually an electric or internal combustion engine. Almost all the energy that is supplied to the compressor is always converted to heat during compression, regardless of the type of compressor. This carries the risk of overheating and therefore the cooling system must be optimally designed. Thus, during the compression of the air, a large part of the electrical energy supplied to the compressor is converted into heat, and only a small part of the supplied energy is in the compressed air. In the case of oil or water-cooled compressors, the exchangers can be used directly to obtain energy "for free". In the case of air cooling, a slight energy gain can only be achieved by modifying the exhaust hot air ducts. This energy can be used efficiently to heat water or heat buildings, instead of being uselessly ventilated. Modern compressors are already adapted for the use of waste heat, but most current companies still use older types of compressors that have not been directly adapted for the use of waste heat. In case of interest in obtaining waste heat, the reconstruction of the facility or development is inevitable.