Numerical Study of an Expandable Multi-layer Thermoelectric Generator System

Abstract

A thermoelectric generator (TEG) system using thin plate framework (TPF) is considered for power generation. As we know, many geothermal and waste heat resources are at low or intermediate temperatures. Such low temperature geothermal energy can be captured effectively by TEG, with no need to apply the traditional high-cost and frequent-maintenance-required technologies, such as Organic Rankine Cycle (ORC) technology and so on. TEG technology is also useful to be applied in distributed power generation. However, most heat exchanger frameworks for TEG are not friendly to mass production, so the high cost spent on heat exchanger system reduces its competitiveness and hinders the large-scale application of thermoelectric technology. In this study, a power generation system is applied to make the best use of thin plate framework (TPF) and thermoelectric generator (TEG) techniques, which aim to reduce the cost, obtain higher heat-to-electricity efficiency and increase the space utilization ratio. Numerical model has been developed to calculate the power output at different inlet temperatures and different temperature differences of hot- and cold-water inlets. The temperature differences used in this study ranges from 30 °C to 90 °C. Based on the analysis of a 1 kW power generation system, the optimization was conducted to give the best temperature difference of hot- and cold-water inlet, the initial temperature of hot water, and the value of water flow rate. The TPF-TEG stack combination patterns are investigated based on the characteristics of outlet temperature. In addition, preliminary economic appraisal was conducted based on modeling results, and it indicates that this multi-layer TEG system has a good application potential in many geothermal sites and distributed waste heat sources.