TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The thermoelectric module comprises a thermoelectric material comprising skutterudites, semi-Heuslers, clathrates, oxides, silicides, borides, bismuth telluride and its derivatives, lead telluride and its derivatives, antimonides including zinc antimonide or simple phases. The phase change material comprises at least one inorganic metal salt having a melting point of 250-1700 degrees C. The metal salt comprises fluorides, chlorides, bromides, iodides, sulfates, nitrates, carbonates, chromates, molybdates, vanadates or tungstates as anions, and lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium or barium as cation. The phase change material comprises salt mixtures which form inorganic metal salts with double, triple, quadruple or quintuple eutectics. The alloy composed of phase change material comprises at least one phase change material and at least one metal alloy with a melting point of 200-1800 degrees C, based on zinc, magnesium, aluminum, copper, calcium, silicon, phosphorus or antimony. The layer of phase change material has been introduced between a pipe and a hot side of the at least one thermoelectric module. The phase change material or alloy composed of phase change material has been integrated in the thermoelectric modules or in the thermoelectric generator, or applied on an inner side of the pipe, or introduced separately between the pipe and the thermoelectric module. The phase change material or alloy composed of phase change material has been introduced over the full area or in sections, parallel or at right angles to the length of the pipe between the thermoelectric module and the pipe. The phase change material or alloy composed of phase change material has been: inserted directly or indirectly between a heat source and the hot side of the thermoelectric modules; and formed in one piece or as at least one thin layer; and formed as an encapsulation around the pipe and/or the thermoelectric module, in which case a package (62) comprises at least one pure metal, including nickel, zirconium, titanium, silver or iron, and/or at least one metal alloy based on nickel, chromium, iron, zirconium or titanium. The phase change material or the alloy composed of phase change material has been installed at any position in an off-gas line, on or in a manifold, on or in an off-gas recycle pipe, on or in an off-gas pipe (10), on or in a silencer or on and/or in a rear silencer. In the thermoelectric generator, a heat exchanger which is present in the off-gas pipe and through which the off-gas flows (20), has an encapsulation or a package of at least one phase change material applied on it, and protects at least one thermoelectric module of a thermoelectric generator from overheating. The phase change material or the alloy comprises at least one phase change material present in a package, which has been applied either on an outer surface of a pipe through which hot off-gas flows, or which surrounds the at least one thermoelectric module. In the thermoelectric generator, an encapsulation thickness within a package of phase change material is constant in relation to embedding of the at least one thermoelectric module, or the encapsulation thickness especially between an outer surface of the off-gas pipe which conducts the hot off-gas flow and the inside of the at least one thermoelectric module, is greater.