Study of Thermoelectric Modules with Self-Powered Tunable Thermal Resistance for Thermal Management and Energy Conservation

Abstract

Tunable thermal resistance is very useful in applications which require a convenient way to regulate temperature differences and heat flow between two thermal bodies. Based on autonomous thermoelectric effects, it is attractive to control thermal conductivity of thermoelectric materials by an external resistance without the need of external power. Thermoelectric modules (TEMs) were originally designed for cooling and heating applications, while in this study, they are further applied in thermal management as a tunable thermal resistor, and for energy conservation as a dynamic insulation material. Six types of TEMs with self-powered tunable thermal resistance have been studied using the guarded hot plate method in terms of single and double configuration under different temperatures and heat flow. Their characteristics of inherent thermal resistance, tunability and tunable range are presented, and the relationship between thermoelement geometry and the dimensionless thermoelectric figure of merit (ZT) are discussed. It is concluded that the higher temperature and heat flow, the lower the thermal resistance. The results show that the inherent thermal resistance and tunability are mainly dependent on thermoelement geometry, and the tunable range is determined by the ZT. The TEC1-12705(40), which has the largest aspect ratio, internal resistance and ZT, is selected to be further tested due its lowest inherent thermal resistance and relatively wide tunable range of thermal resistance, with excellent results. The accuracy of temperature control with an on–off control algorithm was improved from ± &!thinsp;0.3°C to ± 0.1°C in thermal management application. Energy savings is 20.1% compared to static insulated materials in building envelope systems. This work will be the beginning of practical application for thermoelectric materials with self-powered tunable thermal resistance in a thermal system.