Power generation from salinity gradient solar ponds using thermoelectric generators

The thermoelectric devices have been introduced for over 50 years and numerous research and methods have been carried out to improve its conversion efficiency, represented by the figure of merit, Despite having a low conversion efficiency compared to other heat engine, thermoelectric is gaining attention owing to its stationary and simplest operating condition that requires no maintenance. From the literature study conducted, most of the applications of the thermoelectric generators are focusing on generating electricity from a non-storage heat source, which means in order to avoid intermittency in the power supply due to temporary unavailability of adequate heat source; a battery storage system is needed. In order to address an alternative for the aforementioned scenario, a thermal storage system that will able to constantly providing sufficient heat for power generation is proposed, which introduces the solar pond (SP) as the heat source. Acting as a solar energy collector as well as thermal storage, solar ponds have been available in large scale for providing low grade heat source from 50 ºC to 100 ºC. Moreover, in terms of scalability, both thermoelectric generators and solar pond are highly scalable in size. As the thermoelectric cells are able to work interchangeably between heat pump and heat engine, it results in two variations of the thermoelectric cells available in the market, being sold as Peltier cooler and thermoelectric generators, with a significant price difference (the former is costing less than the latter). This study has started by investigating the performance and reliability of the thermoelectric cooler available functioning as thermoelectric generator. Later, in the next chapter, the performance of the thermoelectric cells is incorporated and coupled with a transient heat transfer for solar pond, in order to set up the potential of the thermoelectric-solar pond power generation system. Two practical power generation systems have been brought to fruition and presented in this thesis, which are a plate type power generation unit operating at atmospheric pressure and a submersible type thermoelectric power generation unit, and their comprehensive investigation have been delineated separately in the following chapters. Finally, the outcomes from the prior chapters (the system’s performance via transient model and prototype testing) are joined in the last part of this thesis, to form a sound feasibility study of the system. From the establishment of theoretical framework to the examination of the system's feasibility from the potential and practical viewpoint, this thesis had attended the essential of power generation from solar pond using thermoelectric generators