Performance Evaluation And Parameter Analysis Of Static Hybrid Thermoelectric Conversion System Based On AMTEC

This project mainly focused on the thermoelectric conversion performance of static hybrid thermal to electric conversion system,including the AMTEC/TEC(Alkali Metal Thermal to Electric Converter /Thermoelectric Converter)static hybrid system and TIC/AMTEC/TEC(Thermionic Converter/Alkali Metal Thermal to Electric Converter /Thermoelectric Converter)static hybrid system.Based on the working principle of AMTEC and TEC,the analysis model of AMTEC/ TEC static hybrid system is established firstly from the point of view of energy balance,in which the main internal and external losses of the system are considered.The expressions of the output power and efficiency of the AMTEC subsystem,the TEC subsystem and the AMTEC /TEC hybrid system were derived.In the model,the evaporating temperature and condensing temperature of AMTEC as well as the cold side temperature of TEC are determined by energy balance equations rather than some specified parameters.Based on the model,the performance of AMTEC subsystem,TEC subsystem and AMTEC/TEC hybrid system was evaluated.The influences of load parameters,relevant geometric parameters and operating temperature on property were discussed for each subsystem and AMTEC/TEC hybrid system.The results show that the efficiency of AMTEC/TEC hybrid system is 31.33%,which is about 4% higher than that of AMTEC single system.The parametric analysis shows that,with the increase of AMTEC electrode current density J,the total output power PALL of AMTEC/TEC hybrid system increases monotonously,and the total conversion efficiency ?ALL increases firstly and then decreases.With the increasing of non-dimensional current i of TEC system,both the PALL and ?ALL increase firstly and then decrease.Besides,when the electrode area of AMTEC subsystem is determined,the total output power PALL and efficiency ?ALL will increase with the increase of the heat transfer area between BASE and heat source.Meanwhile,for a particular AMTEC system,there is an optimal matching area of TEC module.The analysis also shows that the TEC geometry has a large effect on the performance of the hybrid system,for any filling rate b of TEC module,there always exists an optimal arm length l of PN couple to maximize the total output power PALL or efficiency ?ALL of the hybrid system,and with the increase of b,the maximum output power and efficiency increase accordingly.In addition,with the increase of the temperature of heat source,the PALL increases significantly while ?ALL increases firstly and then decreased slowly.And the effect of heat sink temperature on thermoelectric conversion performance of AMTEC/TEC hybrid system is small.On the basis of the above work,the TIC/AMTEC/TEC static hybrid system was proposed and the mathematical analysis model of it was developed.Similar to the model of the AMTEC/TEC hybrid system,the temperatures of the TIC/AMTEC/TEC system are also determined by the energy balance.Based on the model,the influence of collector work functions ?c and output voltage VTI of TIC,load parameters,geometric parameters and operating temperature on the thermoelectric conversion performance of each subsystem and the hybrid system were discussed.The results show that the efficiency of TIC/AMTEC/TEC hybrid system is up to 55.34%,which is about 18% higher than TIC single system.The parametric analysis shows that,with the increase of ?c and VTI,the total output power PALL and efficiency ?ALL of TIC/AMTEC/TEC hybrid system increase firstly and then decrease.Meanwhile,PALL and ?ALL are not monotone functions of J,while the TEC load condition has little effect on the thermoelectric conversion performance of the TIC/AMTEC/TEC hybrid system.For a particular TIC system,with the increase of the AMTEC electrode area,the PALL of the TIC /AMTEC /TEC hybrid system increases monotonously and the efficiency ?ALL increases firstly and then decreases,while the ratio of the TEC module area to AMTEC electrode area has weak effect on the performance of the hybrid system.Meanwhile,for any filling rate b of TEC module,there always exists an optimal arm length of PN couple lopt to maximize the total output power PALL,max or efficiency ?ALL,max of the TIC/AMTEC/TEC hybrid system.When b increases,the corresponding lopt is also significantly increased,while the performance improvement of TIC/AMTEC/TEC hybrid system is weak.As a result,the smaller filling rate b is a better choice for TIC/AMTEC/TEC hybrid system.The analysis results also indicate that,for a specific TIC/AMTEC/TEC hybrid system,there exists optimum temperature range of heat source makes the total output power and efficiency have a large value,while the impact of heat sink temperature on performance of TIC/AMTEC/TEC hybrid system is unconspicuous.