Thermal Performance and Integration of Digital Systems in a Water-to-Water Thermoelectric Heat Pump

Abstract

This Paper Investigates the thermal performance of a water-to-water thermoelectric heat pump through the integration of a custom digital monitoring and control system. The study aimed to utilize this system for the experimental determination of the coefficient of performance (COP) under variable influencing factors. Heat transfer was carried out due to the Peltier effect, where the flow of electric current through the converter simultaneously caused heat absorption and heat emission at its thermal sides. Heat exchange on each side was implemented by forced circulation of liquid heat carriers. At one stage of the experiment, the variation of temperature indicators on each side of the converter was investigated with increasing electric current in the range of 3–9 A. On the hot side, the temperature increased linearly from 23.6 °C to 39 °C, while on the cold side it decreased nonlinearly from –4.8 °C to –18.56 °C. At another stage, under steady heat exchange conditions with varying current and heat carrier temperatures, the absorbed and emitted heat and the electrical power consumption of the system were determined. With increasing current, the heat emission Qhot rose linearly from 22 to 118 W, while the electrical power consumption of the heat pump varied quadratically from 16.9 to 155.65 W. The maximum COP reached 135.5%, but decreased exponentially with increasing current, crossing the economically viable threshold of 100% at 7 A. The best results were obtained when transforming thermal energy from a low-temperature source at 15 °C to a high-temperature source at 20 °C.