Cogeneration function: CHP is the decentralized use of the electricity generated and the heat produced.
An engine or gas turbine directly drives a machine such as a generator or a compressor. The engines are mainly modified petrol or diesel engines from mass production for cars and trucks with small and medium power range. For CHP systems with large electric power range, marine diesel engines are frequently used. Most of the exhaust heat and the waste heat from cooling water and engine oil is used via heat exchangers as useful heat for the heating and heating of water. The proportion of useful heat from exhaust gas and cooling water varies depending on the engine-power class of the CHP.
With small engines, the waste heat outweighs cooling water. For large engines, it is about the same size. In gas turbines, the useful heat is obtained exclusively from the exhaust gases.