Optimal Analysis On The Performance Characteristics Of Irreversible Semiconductor Thermoelectric Refrigerator And Generator

The energy conversion systems of semiconductor thermoelectric refrigeration or generation have many advantages such as cleanness, quiet, no pollution, small size, light weight, no mechanical moving parts, long life, and so on. It accords with a green environmental protection request and has important strategic meaning for keeping a continual development of the national economy. Along with the breakthrough development of semiconductor materials, the research on the optimal performance characteristics of the semiconductor thermoelectric refrigerators and generators and their applications have become a popular topic. In this thesis, the optimal problems on the performance characteristics of semiconductor thermoelectric refrigerators and generators are, respectively, discussed on the basis of non-equilibrium thermodynamics.In chapter 1, the development status of the semiconductor thermoelectric devices is introduced simply and the current research relative to these devices is described. In chapter 2, the relevant principles of semiconductor thermoelectric devices are introduced in detail. The relations between the figure of merit of semiconductor thermoelectric devices and the Seebeck effect, Peltier effect and Thomson effect are analyzed. In chapter 3, the optimal performance of an irreversible semiconductor thermoelectric refrigerator is investigated. The influence of the external and internal irreversibilities of the thermoelectric device on the performance of the system is analyzed. The general expressions of the coefficient of performance and power input are derived by introducing some dimensionless parameters and variables. The coefficient of performance of the refrigeration device is maximized for given cooling load and total heat transfer area of the system, and consequently, the structure parameters of the device and the area ratio of the heat exchangers of the system are determined optimally. The effects of the various parameters on the optimum performance of the device are discussed further. In chapter 4, the performance of an irreversible semiconductor thermoelectric generator is investigated. The influence of the various irreversibilities on the performance of the system is analyzed. The general expressions of two important performance parameters, the efficiency and power output, are derived. The efficiency of the system is maximized for given heat supplying and total heat transfer area of the system. Moreover, the effects of the various parameters on the optimum performance of the system are discussed in detail. The results obtain in this thesis will be useful for a more detailed investigation and for the optimal design of real thermoelectric systems...