Experiments were performed on a heat exchanger equipped with multiple thermoelectric (TE) modules. The primary objective was to design a simple, but effective, modular Peltier heat pump system component to provide chilled or hot water for domestic use. Moreover, the modular design of this system component is such that the total system capacity is scalable such that it can potentially be used for hydronic building climate control of small solar residences, where the TE devices could be directly energized using solar powered PV panels, and coupled with the building inlet water supply heat sink and grey water heat recovery, providing a renewable, pollution free and cost-effective solutions to the home energy problem.
First, the work focuses on the design and testing of a thermoelectric heat exchanger component that consists of two water channels machined from two aluminum plates with an array of three or five thermoelectric modules placed in between to cool and/or heat the water. Then the work focuses on the detailed convection analysis inside the TE-HX component when 10 thermoelectric modules are utilized. The local heat transfer coefficient at different points along the channel are measured at steady-state, first, when a continuous heater is installed and then when replaced with 10 TE modules. The experimental heat transfer coefficients obtained are compared with available empirical correlations for developing “transition” (3000 < ReDh < 7000) turbulent flow inside the channel with fair-to-good results. Next, the resulting coefficient-of-performance of the TE heat pump system is measured with its value depending both on system input power and water flow rate. Testing showed that performance degradation, i.e. reduced COPs, occurred when operated at higher power levels but remains satisfactory for up to 688 Watts with higher flow rate. A comparison of the system performance with different TE module arrangements at different power level has also been made which gives the clear insight for best system configuration with TE modules to achieve optimum performance.