Concept, modeling and experimental evaluation of an integrated cooling, heating and thermoelectric generation system

A concept of an integrated system for cooling, heating and electricity generation using thermoelectric effect and water is presented. The concept consists of two 2-L capacity water reservoirs: The first one has been used to store cold water and the second one to store heated water. Both reservoirs are thermally connected by two thermoelectric modules, which can be used to heat and cool the water when supplying electrical energy to the modules or generate electricity when hot and cold water are stored in these two reservoirs. A theoretical model of the system is developed for transient simulation where heat transfer and energy conservation differential equations were numerically solved and a real prototype was built. The model uses the maximum performance parameters available in commercial thermoelectric datasheets to obtain all other relevant thermoelectric variables. The agreement between the developed model and the experiment was close to 95%, and the proposed system was able to cool water near zero degrees Celsius, to heat it near the water boiling point, and generate more than 1.5 W of electrical power when operated as thermoelectric generator using heated water and cold water with 70 °C temperature. The simulations also showed that water reservoirs of 25 L capacity, with initial temperatures of 95 °C for hot water and 25 °C for cold water, can be used to supply peak electrical power of 2.3 W and mean power of 1 W for 12 h, energy equivalent 6 AA alkaline batteries. This system has the potential to be applied for sustainable cooling, heating and electricity generation in isolated communities and in non-urban regions.