Numerical simulation, parametric study and optimization of thermoelectric generators for self-cooling of devices

Abstract

Thermoelectric generation is a promising technology which converts waste heat into electricity in an efficient and clean way. Thermoelectric application could utilize the heat from a device to power a thermoelectric generator (TEG) which in turn produces power that could run a cooling system. Such systems would be critical in transportation, remote area or other applications where system reliability is of a paramount importance. Thus, in this paper a detailed parametrical analysis and optimization of the geometrical and system parameters are made so as to provide guidelines for the design of self-cooling devices. A simple and accurate 2D numerical model is developed which facilitates a quick analysis of design variables. Numerical data is within a good agreement (within 6%) with existing experimental data. The effect of extender height (Hext), fin base height (Hfbase), number of fins (Nfin) ranging from 10 mm to 50 mm, 2 mm to 12 mm, 24 to 64 respectively has been studied. In addition, the feasibility of using double and triple cascaded TEG system is investigated. An optimization algorithm to optimize system paramaters is implemented. Nomenclature h = convection heat transfer coefficient (W/m 2 .K) Tg = temperature inside the device H = height(mm) Th = temperature at hot side of TEG I = electric current (A) Ts = temperature at cold side of TEG = current density (A/m 2 ) Tamb = ambient temperature k = thermal conductivity (W/m.K) v = velocity of air in fan (m/s) l = length (mm) w = width (mm) n = n-type semiconductor elements x,y = Cartesian coordinates Nfin = number of fins p = p-type semiconductor elements P = electric power (W) g Q  = heat generation rate (W) R = thermal resistance (K/W) Rel = electric resistance of the thermoelectric module (Ω) Rld = electric load resistance connected to the module (Ω) Rth = thermal resistance of the thermoelectric module (K/W) T = temperature (°C) t = time (s) Greek Symbols  = seebeck coefficient (V/K) ρ = electrical resistivity (Ωm) ΔT = temperature difference 1 PhD Student, Department of Mechanical and Materials Engineering, Miami, Florida. AIAA student member. 2 Associate Professor, Department of Mechanical and Materials Engineering, Miami, Florida. AIAA member. 3 Visiting PhD Researcher, Department of Mechanical and Materials Engineering, Miami, Florida.