Investigation On The Performance Of The Thermodynamic Cycle In A Small Quantum System

In order to make more efficient use of various low grade waste heat,the cascade utilization of energy is achieved,and the thermodynamic cycle efficiency and power are finally improved.Based on the thermodynamic cycle in the traditional macroscopic sense,this paper studies the performance characteristics of the thermodynamic cycle under the micro scale,and establishes a micro scale quantum Stirling heat engine cycle model and a micro scale quantum Stirling refrigeration cycle model based on the ideal Bose or Fermi gas in the confined space as thermodynamic properties.Based on the traditional single power module,applying the theory of non-equilibrium thermodynamics,the theoretical model of solar driven thermionic thermo-electric device-semiconductor thermoelectric device hybrid power system is established.The output power and efficiency of the micro scale quantum Stirling heat engine cycle,micro scale quantum Stirling refrigeration cycle and the solar driven thermionic-thermoelectric hybrid generation system are calculated.The performance characteristics and optimize the properties of micro scale quantum Stirling heat engine and micro scale quantum Stirling refrigeration cycle are analyzed.The results can provide two new methods in order to make use of each grade of heat more effectively.The main research work of this paper is summarized as follows:1.The cycle model of a micro-scaled quantum Stirling heat engine using an ideal Bose or Fermi gas in a confined space as the working substance is established,in which the finite-size of the working substance is taken into account.Based on the thermodynamic properties of a confined ideal Bose or Fermi gas,the general performance of the cycle and the combined effects of quantum boundary and degeneracy on the performance of the cycle are investigated.The inherent regenerative losses of the cycle are analyzed and calculated.The general expressions of the efficiency and work output of the cycle.The curves of the efficiency and work output of the cycle versus the volume and surface area ratios of the cycle and the efficiency versus the work output are represented.The influence of thermosize effects on the efficiency and work output are discussed.The general performance characteristics of the cycle are revealed.2.The cycle model of a micro-scaled quantum Stirling refrigeration using an ideal Bose or Fermi gas in a confined space as the working substance is established,in which the finite-size of the working substance is taken into account.The inherent regenerative losses of the cycle are analyzed and calculated.The general expressions of the efficiency and work output of the cycle.The influence of thermosize effects on the performance of a micro quantum Stirling refrigeration cycle are discussed.The general performance characteristics of the cycle are revealed.It is found that both the out power and coefficient of performance of the micro-scaled quantum Stirling refrigeration cycle depend on the surface area of the cyclic system besides the temperature of the heat reservoirs,the volume of cyclic system and other parameters.3.A theoretical model of solar driven thermionic-thermoelectric hybrid power system is established.Applying the theory of non-equilibrium thermodynamics,the output power and efficiency of the thermionic generator,thermal electric and hybrid power system is derived respectively.By using the law of conservation of energy,the equation of the internal energy balance is calculated.Some new conclusions are obtained.The optimization performance characteristics of the thermionic thermoelectric hybrid power generation system driven by solar energy are analyzed,and the optimization range of the focusing degreeCI_s,the output voltageV_TIGof the thermionic generator and the load resistance of thermal electric is obtained.The results can provide a theoretical basis for the design and optimization of the actual hybrid power generation system.