International Journal of Innovative Research in Engineering & Management (IJIREM) ISSN: 2350-0557, Volume-3, Issue-4, July-2016 Copyright © 2016. Innovative Research Publications. All Rights Reserved 259 Review Paper on Optimizations of Thermoelectric System Krishna Purohit Mechanical Department, JNVU / MBM Engineering College, Jodhpur, India, Sheetal Kumar Jain Mechanical Department, RTU / Apex Institute of Engineering Technology, Jaipur, India, Dr. P M Meena (PhD-IITB) Associate Professor Mechanical Department, JNVU / MBM Engineering College, Jodhpur, India, Khushaboo Singh Mechanical Department, JNVU / MBM Engineering College, Jodhpur, India, Manish Dadhich CFD Engineer Grob Design Pvt. Ltd. Jaipur, India ABSTRACT Thermal management and energy crisis have been two major problems in this 21st century. Engine exhaust has tremendous amount of energy which can be recovered by waste heat recovery systems. The thermoelectric concept is seen as a perfect solution for recovering waste heat from engine exhaust and converts in to electric energy. Since the use of semiconductor materials for thermoelectric applications, there has been a huge quest for improving its figure of merits (ZT) to make it commercially viable. This synopsis report presents the simulation and experimental validation study on the transient behavior of a proposed combined exhaust heat recovery device and thermoelectric power generation system. The proposed system consists of waste heat recovery that provides a heat flux source for thermoelectric generators. In this research, thermoelectric generator device are consist of two major part, first one is exhaust recovery device and second one is thermoelectric generation system. In the first phase of study, optimize the waste heat recovery system design, performed cfd analysis and get heat and temperature data then cfd model coupled with thermoelectric model, find out the thermoelectric effect on particular devices. This paper presents of numerical simulation for several the thermoelectric materials. Numerical simulation is carried out by using a finite element package ANSYS. Keywords Thermoelectric Generator (TEG), Thermoelectric Material (TEM) Automotive Exhaust, Numerical Simulation. 1. INTRODUCTION Thermoelectric generators are all solid-state devices that convert heat into electricity. Unlike traditional dynamic heat engines, thermoelectric generators contain no moving parts and are completely silent. Such generators have been used reliably for over 30 years of maintenance-free operation in deep space probes such as the Voyager missions of NASA.1 Compared to large, traditional heat engines, thermoelectric generators have lower efficiency. But for small applications, thermoelectric can Become competitive because they are compact, simple (inexpensive) and scale able. Thermoelectric systems can be easily designed to operate with small heat sources and small temperature differences. Such small generators could be mass produced for use in automotive waste heat recovery or home co-generation of heat and electricity. A thermoelectric produces electrical power from heat flow across a temperature gradient. As the heat flows from hot to cold, free charge a carrier (electrons or holes) in the materials are also driven to the cold end. The resulting voltage (V) is proportional to the temperature difference (∆T) via the Seebeck coefficient, α, (V = α ∆T). By connecting an electron conducting (n-type) and hole conducting (p-type) material in series, a net voltage is produced that can be driven through a load. A good thermoelectric material has a Seebeck coefficient between 100μV/K and 300μV/K; thus, in order to achieve a few volts at the load, many thermoelectric couples need to be connected in series to make the thermoelectric device. A thermoelectric generator convert’s heat (Q) into electrical power (P) with efficiency η. P = η Q (1) The amount of heat, Q, that can be directed though the thermoelectric materials frequently depends on the size of the heat exchangers used to harvest the heat on the hot side and reject it on the cold side. The thermoelectric systems have been the subject of major advances in recent years, due to the development of semiconductors and the incorporation of the thermoelectric devices into domestic appliances. Generally, if a thermal gradient is applied to a solid, it will always be accompanied by an electric field in the opposite direction. This process is called as the thermoelectric effect. Thermoelectric material applications include refrigeration or electric power generation. The efficiency of a thermoelectric material is given by the figure of merit, Z, which is defined as [2]: Z = α 2 σ/k, [1/k] (2) Where: α - Material's Seebeck coefficient, V/K, σ - Electrical conductivity of material, S/m, k – Thermal conductivity of material, W/ (m. K). The numerator in equation (2) is called the power factor. Therefore, the most useful method in order to describe and compare the quality and thermoelectric efficiency of different material systems is the dimensionless figure of merit (ZT), where