Optimization strategies to enhance waste heat recovery from engine coolant using thermoelectric devices

Engine coolants absorb almost 20% of the fuel’s energy as waste heat. An optimization strategy has been proposed in this study for the design of radiator of the vehicle equipped with TEG devices for maximizing energy conversion from waste heat. Cooling fin design of the radiator has been parametrically studied using computational methods. Additionally, the quantity of energy that might be recovered from the coolant has been approximated based on the experimental results of a large compression ignition engine. Effect of using additional radiators without cooling fans to increase energy extraction has been studied. Results have shown that the cooling fin design needs large modifications to incorporate TEGs on the radiator channels. It has been determined that a fin height of 6 mm and a pitch of 6.5 mm, in combination with the utilization of a base plate, provide the most optimal conditions for achieving maximum heat recovery and power generation. It has been noted that higher air flow rates and inlet coolant temperatures contribute to improved heat recovery and power generation. Estimates show that though the TEG efficiency is low, up to 5.14 kW of energy can be extracted from the coolant. Further, a 4.81 kW of energy can be extracted if an additional radiator is placed facing the airflow of the vehicle. Estimates show that up to 9.95 kW of power can be generated using the coolant heat alone on a 750 kW engine.