AN ELECTRIC CONVERSION SET OF GEOTHERMAL ENERGY USING A THERMOELECTRIC DEVICE: CASE AT A HOT SPRING

This research aims to study the effects of hot- and cold-water flowrates on electrical production of a thermoelectric device to design and build a heat-to-electricity conversion kit block. A test stand was used to simulate the Raksawarin Hot Springs, Ranong Province in Thailand. This hot spring has a temperature of 65 °C and cold water from a nearby canal at 27 °C. We use 20 sheets of a thermoelectric material (TE) model TEC1-12706, size 40x40 mm2, designed as hot and cold-water blocks with dimensions of 200 x 50 x 660 mm3. The natural temperature of this hot spring, 65±2 °C, and cold-water stream at 27±2 °C, were simulated. An experimental test stand that provides hot water was controlled by a thermostat. The cold-water flow is controlled using a water pump and flow meter. Experimental results showed that at equal hot- and cold-water flowrates of 2.0 liters per minute, the average maximum voltage was 0.12 V for each TE generator. In the case of 20 TE pads (10 pcs. in series and two sets in parallel) under a constant hot water flowrate of 2.5-5 liters per minute, the TE plates generated maximal power, about 2.0 V, 170 mA, and 0.3-0.4 Watts.