Case study on thermoelectric generation system utilizing the exhaust gas of interal-combustion power plant

This paper discusses the effects of element length, installation of fins and exhaust gas flow rate on the power output and the conversion efficiency of a thermoelectric generation system using the exhaust gas of an internal combustion plant. The thermoelectric module consists of bismuth-tellurium based thermoelectric elements, electrodes, insulators, etc. A thermoelectric generation system consists of thermoelectric generation modules sandwiched by two square heat transfer tubes inside which exhaust gas and cooling water flow in a counter-current. It is supposed that the thermoelectric generation system recovers the heat of the exhaust gas of 60000 Nm³/h at 370°C of an internal-combustion plant whose declared power is 10000 kW until it falls to 180°C, and converts it into electricity. The power generation performance is obtained by the heat balance equations in the steady status between fluids and thermoelectric elements for each thermoelectric element inside the system and performing interactive calculations repeatedly. The power generation performance depends on the element length, the heat transfer area inside the hear transfer tube and the exhaust gas flow rate. As the difference between the temperature applied on the upper portion of the element and the temperature applied on the lower portion of the element becomes larger, the power generation performance is improved. The power output of 184 kW is recovered from the heat of exhaust gas of an internal-combustion plant whose declared output is 10000 kW when the element length is 15.2 mm, the fin efficiency is 4 and the exhaust gas flow rate per tube is 1212 Nm³ /h