Experimental testing and mathematical modeling of a thermoelectric based hydronic cooling and heating device with transient charging of sensible thermal energy storage water tank.

摘要

Sensible charging of cold and hot water thermal energy storage tanks has been studied experimentally and theoretically using 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 at the appliance level; and when arranged in multiple unit combinations, a system that can potentially satisfy small home cooling and heating requirements. Moreover, when the TEs are directly energized using solar PV panels, the system provides a renewable, pollution free and off-the-grid solution to supplement home energy needs.;The present work focuses on the (1) design, (2) testing and (3) theoretical modeling 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 transiently cool and/or heat the water in the thermal energy storage tank. The water passing over either the cold or hot side of the TE modules is recirculated to charge the cold or hot thermal storage tank, respectively. The temperatures in the prototype Peltier heat exchanger test component and thermal energy water storage tank were measured during both cold tank charging and hot tank charging operation. In addition, a mathematical model was developed and numerically solved to predict the charging of cold and hot water tanks using thermoelectric modules heat exchanger device. Equations are developed for the heat pumped by the TE module as a function of the temperature difference across it for the appropriate values of the heat sink temperatures. These equations, along with those for the three lumps, are then finite differenced with a stable time step, so that a smooth variation of temperatures could be obtained. The temperature history of the tank water, thus obtained as a function of time using a three-lumped parameter model is compared to the experimental data. The thermal efficiencies of TE heat pump cooling/heating system are reported. The effects of TE power input, number of TE units and rate of fluid flow are studied.