Advanced Phase-Change Intermediate Heat Exchanger Development for Multistage Thermoelectric Heat Pumps

The need to reach a full energy decarbonisation is well known. Heating and cooling consumption is almost half of the global energy end-use. Thus, development of low-carbon and highly efficient power-to-heat technologies must be developed. In this work, the use of thermoelectric technology working as a heat pump is proposed to heat up an airflow of 38 m3/h. Two different prototypes of multistage thermoelectric heat pumps have been developed and compared based on monophasic and phase-change intermediate heat exchangers. The reduced thermal resistance obtained for the novel phase-change heat exchanger increases the heat flux supplied to the airflow and reduces the consumed power of the system, outperforming the operation of the monophasic ther-moelectric heat pump between a 30 and a 67 %. The novel multistage phase-change heat pump obtains experimental COP values between 3.25 and 1.26 when the airflow rises its temperature from 3.5 degrees C to 23.5 degrees C. Additionally, this experimental study proves a new methodology to calculate the supplied heat flux to the airflow. The validation of this technology proves a discrepancy of +/- 9 % when this novel technology is compared to the conventional one based on the airflow temperature rise.

Automated summary

This study proposes a low-carbon and highly efficient heating technology using thermoelectric technology as a heat pump, and compares two different prototypes of thermoelectric heat pumps. The novel phase-change heat exchanger demonstrates superior thermal conductivity and energy efficiency. The experimental results validate the feasibility of this technology and propose a new method for calculating the heat supply.