This article presents the temperature-entropy analysis, where the Thomson effect bridges the Joule heat and the Fourier heat across the thermoelectric elements of a thermoelectric cooling cycle to describe the principal energy flows and performance bottlenecks or dissipations. Starting from the principles of thermodynamics of thermoelectricity, differential governing equations describing the energy and entropy flows of the thermoelectric element are discussed. The temperature-entropy (T-S) profile in a single Peltier element is pictured for temperature dependent Seebeck coefficient and illustrated with data from commercial available thermoelectric cooler. (c) 2006 Elsevier Ltd. All rights reserved.