Automotive Thermoelectric Generator - Problems

Problems

The use of an ATEG presents new problems to consider:

Since the exhaust has to flow through the ATEG’s heat exchanger, kinetic energy from the gas is lost, causing increased pumping losses. This is referred to as back pressure, which reduces the engine’s performance.

To make the ATEG’s efficiency more consistent, coolant is usually used on the cold-side heat exchanger rather than ambient air so that the temperature difference will be the same on both hot and cold days. This increases the radiator’s size since piping must be extended to the exhaust manifold. It also adds to the radiator’s load because there is more heat being transferred to the coolant.

ATEGs are made primarily of metal and, therefore, contribute a significant weight to the vehicle. An ATEG designed for small cars and trucks weighs about 125 lb (57 kg), while for large trucks and SUVs, it can contribute up to 250 lb (110 kg) to the vehicle. The added weight causes the engine to work harder, resulting in lower gas mileage.

Cost is a prevalent issue in ATEGs. Thermoelectric generators with higher efficiencies require higher quality, more expensive thermoelectric materials. With the thermal cycling and vibration of the vehicle, the generator’s longevity is a concern. Although high quality thermoelectric materials could produce more electricity, the cost of replacing them could outweigh the savings in fuel economy.