Investigation on Solar/Thermoelectric Tube for Heating and Generation

This paper presents an experimental study of a hybrid thermoelectric module (TE) and solar tube for heating and generation. This prototype solar/TE unit comprised a vacuum heat pipe solar tube, three thermoelectric generation modules (TEG) with one side connected to the oil tank inside the tube and the other side connected to the heat pipe, one thermoelectric heating module (TEC) and an aluminum heat sink. A system includes one solar/TE unit, and water circuit, including a tank, pump and pipe work. A halogen lighting array simulated solar irradiance for indoor tests. Temperatures, flow rates, solar intensity and voltage generated were measured. Tests were carried out at 800 W/m² while the electrical current supplied to TEC was maintained at 0A, 1A, 2A, 3A and 4A separately. A variable electrical resistor and one 1 ohm resistor were used to measure the electrical performance of TEG by measuring the voltage. It was found that: (1) with the increase of load of resistor, there will be a maximum power output when the load of resistor is the same as the inner resistance of TEG (2) with the increase of current supplied to TEC, power output increases under the same load of resistor, and thermal efficiency increases too (3) the maximum thermal efficiency was about 61% when current was at 4A and the minimum thermal efficiency was about 50% when current was 1A (4) with an increase in time, temperature difference of hot side and cold side temperature of TEG increase slowly. The more current supplied to TEC, the larger the temperature difference of TEG will be.