Introduction to Thermal Equivalent Circuits

This chapter focuses on thermal equivalent circuits (TECs). It utilizes the Heat to derive a TEC of a region with one‐dimensional heat flow. This circuit will be exact in steady state and will be capable of predicting transient behavior, albeit only approximately. The chapter develops a TEC for a cuboidal region, and considers the TEC of a cylindrical region. It also considers the interconnection of TECs of individual regions of a device in order to form and solve TEC for an entire device. The chapter discusses the solution of the TEC using nodal analysis. It introduces some notation for TECs in order to reduce our effort in describing complex thermal circuits. In electrical circuits, the interconnection of circuit components is based on Kirchoff's voltage and current laws, which state that sum of the voltage drops across a closed path is zero, and that the sum of the currents going into a node is zero.