The thermoelectric figure of merit is investigated, taking bulk and surface parameters into account. The electron and phonon temperatures are supposed to be different. It is shown that the thermoelectric figure of merit increases as sample dimensions decrease when the electron subsystem has an isotropic heat contact with the thermostat and the phonon subsystem has an adiabatical one.
{"title":"Thermoelectric figure of merit of bounded semiconductors","authors":"G. Logvinov, V. Zakordonets","doi":"10.1109/ICT.1996.553295","DOIUrl":"https://doi.org/10.1109/ICT.1996.553295","url":null,"abstract":"The thermoelectric figure of merit is investigated, taking bulk and surface parameters into account. The electron and phonon temperatures are supposed to be different. It is shown that the thermoelectric figure of merit increases as sample dimensions decrease when the electron subsystem has an isotropic heat contact with the thermostat and the phonon subsystem has an adiabatical one.","PeriodicalId":447328,"journal":{"name":"Fifteenth International Conference on Thermoelectrics. Proceedings ICT '96","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128040578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The optimal control methods are used in the present work for a search of the best function of thermoelectric material inhomogeneity. The possibility of an increase in low-temperature cooler coefficient of performance due to the use of thermoelectric material inhomogeneity, has been demonstrated.
{"title":"Optimal functions as an effective method for thermoelectric devices design","authors":"L. Anatychuk, O. Luste, L. Vikhor","doi":"10.1109/ICT.1996.553304","DOIUrl":"https://doi.org/10.1109/ICT.1996.553304","url":null,"abstract":"The optimal control methods are used in the present work for a search of the best function of thermoelectric material inhomogeneity. The possibility of an increase in low-temperature cooler coefficient of performance due to the use of thermoelectric material inhomogeneity, has been demonstrated.","PeriodicalId":447328,"journal":{"name":"Fifteenth International Conference on Thermoelectrics. Proceedings ICT '96","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127495528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. V. Wagner, R. Foreman, L. Summers, T. Barbee, J. Farmer
Two thin-film thermoelectric devices are experimentally demonstrated. The relevant thermal loads on the cold junction of these devices are determined. The analytical form of the equation that describes the thermal loading of the device enables us to model the performance based on the independently measured electronic properties of the films forming the devices. This model elucidates which parameters determine device performance, and how they can be used to maximize performance.
{"title":"Fabrication and testing of thermoelectric thin film devices","authors":"A. V. Wagner, R. Foreman, L. Summers, T. Barbee, J. Farmer","doi":"10.2172/212542","DOIUrl":"https://doi.org/10.2172/212542","url":null,"abstract":"Two thin-film thermoelectric devices are experimentally demonstrated. The relevant thermal loads on the cold junction of these devices are determined. The analytical form of the equation that describes the thermal loading of the device enables us to model the performance based on the independently measured electronic properties of the films forming the devices. This model elucidates which parameters determine device performance, and how they can be used to maximize performance.","PeriodicalId":447328,"journal":{"name":"Fifteenth International Conference on Thermoelectrics. Proceedings ICT '96","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125725692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper is an introduction and theoretical investigation of the fast-transient cooling characteristics of a TE module under applied high-current electrical pulses. A temperature-dependent, finite element model was developed to accurately model the fast-transient performance. Analysis of experimental data is presented to verify the accuracy and validity of the model and the conclusions derived therefrom. It has been shown that cold plate temperatures are achievable from a typical TE module beyond that obtainable by conventional, steady-state means. The cooling enhancement is by virtue of the fact that Peltier cooling is a surface effect and extremely concentrated at the cold junction, whereas, Joule heating is a volume effect and is distributed throughout the volume of the TE pellet. As such, most of the Joule heat takes a longer time to reach the cold plate than the Peltier cooling effect. This phenomenon is theoretically demonstrated by applying a high-current pulse after the minimum steady-state cold plate temperature has been established. Calculations have shown that cold plate temperatures can be reduced by 16 K below that via steady-state means. These transient enhancements are admittedly short-lived and have limited effectiveness. However, the results presented herein suggest that further exploitation of the fundamental differences between Peltier and Joule heat are possible. A concept is re-introduced which consists of thermally and electrically separating the cold electrode from the TE pellet.
{"title":"Theoretical analysis of thermoelectric cooling performance enhancement via thermal and electrical pulsing","authors":"R. Buist, P. G. Lau","doi":"10.1109/ICT.1996.553306","DOIUrl":"https://doi.org/10.1109/ICT.1996.553306","url":null,"abstract":"This paper is an introduction and theoretical investigation of the fast-transient cooling characteristics of a TE module under applied high-current electrical pulses. A temperature-dependent, finite element model was developed to accurately model the fast-transient performance. Analysis of experimental data is presented to verify the accuracy and validity of the model and the conclusions derived therefrom. It has been shown that cold plate temperatures are achievable from a typical TE module beyond that obtainable by conventional, steady-state means. The cooling enhancement is by virtue of the fact that Peltier cooling is a surface effect and extremely concentrated at the cold junction, whereas, Joule heating is a volume effect and is distributed throughout the volume of the TE pellet. As such, most of the Joule heat takes a longer time to reach the cold plate than the Peltier cooling effect. This phenomenon is theoretically demonstrated by applying a high-current pulse after the minimum steady-state cold plate temperature has been established. Calculations have shown that cold plate temperatures can be reduced by 16 K below that via steady-state means. These transient enhancements are admittedly short-lived and have limited effectiveness. However, the results presented herein suggest that further exploitation of the fundamental differences between Peltier and Joule heat are possible. A concept is re-introduced which consists of thermally and electrically separating the cold electrode from the TE pellet.","PeriodicalId":447328,"journal":{"name":"Fifteenth International Conference on Thermoelectrics. Proceedings ICT '96","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127735252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The distribution of thermal stresses in thermoelectric columns with superlattice structure was analyzed by numerical simulation. This analysis focused on Bi/sub 2/Te/sub 3/ compounds used for cooling purpose. The dimensions used for analysis are achievable by using metal organic chemical vapor deposition (MOCVD), technology which can economically fabricate high quality thermoelectric devices. Various mechanical constraints were used for simulation. The calculated stresses within thermoelectric (TE) devices made of bulk material were also evaluated. Because the superlattice structure assembly is mechanically similar to other thin film designs, these results can be applied to TE devices made by different thin film techniques.
{"title":"Robust thin film thermoelectric devices","authors":"C. Chu","doi":"10.1109/ICT.1996.553317","DOIUrl":"https://doi.org/10.1109/ICT.1996.553317","url":null,"abstract":"The distribution of thermal stresses in thermoelectric columns with superlattice structure was analyzed by numerical simulation. This analysis focused on Bi/sub 2/Te/sub 3/ compounds used for cooling purpose. The dimensions used for analysis are achievable by using metal organic chemical vapor deposition (MOCVD), technology which can economically fabricate high quality thermoelectric devices. Various mechanical constraints were used for simulation. The calculated stresses within thermoelectric (TE) devices made of bulk material were also evaluated. Because the superlattice structure assembly is mechanically similar to other thin film designs, these results can be applied to TE devices made by different thin film techniques.","PeriodicalId":447328,"journal":{"name":"Fifteenth International Conference on Thermoelectrics. Proceedings ICT '96","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115570717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermoelectric generators and cooling devices present several advantages compared to other energy conversion technologies: they are reliable, can operate unattended in hostile environments, and are also environmentally friendly. However, their application has been limited up to now because of the relatively low conversion efficiency of traditional thermoelectric materials used in the devices. New more efficient materials are needed. A new class of semiconducting materials was identified at JPL a few years ago and the study of the properties of these materials for thermoelectric and other applications has been subject to a growing interest. Recent findings on the physical-chemical and transport properties of skutterudite materials are reviewed. Results obtained on binary compounds showed that their lattice thermal conductivity is too high to achieve high thermoelectric figures of merit. Several approaches have been recently proposed to decrease the lattice thermal conductivity of skutterudite materials. They are described and illustrated by recent experimental results. It is shown that low thermal conductivity can be achieved and high ZT values are possible for skutterudites.
{"title":"Skutterudites for thermoelectric applications","authors":"T. Caillat, J. Fleurial, A. Borshchevsky","doi":"10.1109/ICT.1996.553265","DOIUrl":"https://doi.org/10.1109/ICT.1996.553265","url":null,"abstract":"Thermoelectric generators and cooling devices present several advantages compared to other energy conversion technologies: they are reliable, can operate unattended in hostile environments, and are also environmentally friendly. However, their application has been limited up to now because of the relatively low conversion efficiency of traditional thermoelectric materials used in the devices. New more efficient materials are needed. A new class of semiconducting materials was identified at JPL a few years ago and the study of the properties of these materials for thermoelectric and other applications has been subject to a growing interest. Recent findings on the physical-chemical and transport properties of skutterudite materials are reviewed. Results obtained on binary compounds showed that their lattice thermal conductivity is too high to achieve high thermoelectric figures of merit. Several approaches have been recently proposed to decrease the lattice thermal conductivity of skutterudite materials. They are described and illustrated by recent experimental results. It is shown that low thermal conductivity can be achieved and high ZT values are possible for skutterudites.","PeriodicalId":447328,"journal":{"name":"Fifteenth International Conference on Thermoelectrics. Proceedings ICT '96","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116723153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The main advantage of thermoelectricity compared to conventional techniques of refrigeration and electricity generation lies in the absence of mechanical parts such as motors and compressors. Free convection based exchangers yield maximal safety due to the absence of fan or pump. We describe an electricity generating thermoelectric unit of the above type; it is designed for a small nuclear-powered submarine suitable for deep sea oil prospection. The purpose of the unit is to power an alarm system in case of reactor failure.
{"title":"Free convection and electrical generation with thermoelectrics","authors":"J. Buffet","doi":"10.1109/ICT.1996.553512","DOIUrl":"https://doi.org/10.1109/ICT.1996.553512","url":null,"abstract":"The main advantage of thermoelectricity compared to conventional techniques of refrigeration and electricity generation lies in the absence of mechanical parts such as motors and compressors. Free convection based exchangers yield maximal safety due to the absence of fan or pump. We describe an electricity generating thermoelectric unit of the above type; it is designed for a small nuclear-powered submarine suitable for deep sea oil prospection. The purpose of the unit is to power an alarm system in case of reactor failure.","PeriodicalId":447328,"journal":{"name":"Fifteenth International Conference on Thermoelectrics. Proceedings ICT '96","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133468647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Experimental investigations have been performed on the thermoelectric properties on the multiple-quantum-well structures of PbTe/Pb/sub 1-x/Eu/sub x/Te grown by molecular beam epitaxy. Our results are found to be consistent with theoretical predictions and indicate that an increase in Z over bulk values may be possible through quantum confinement effects using quantum-well structures.
{"title":"Experimental study of the effect of quantum-well structures on the thermoelectric figure of merit","authors":"L. D. Hicks, T. Harman, X. Sun, M. Dresselhaus","doi":"10.1109/ICT.1996.553525","DOIUrl":"https://doi.org/10.1109/ICT.1996.553525","url":null,"abstract":"Experimental investigations have been performed on the thermoelectric properties on the multiple-quantum-well structures of PbTe/Pb/sub 1-x/Eu/sub x/Te grown by molecular beam epitaxy. Our results are found to be consistent with theoretical predictions and indicate that an increase in Z over bulk values may be possible through quantum confinement effects using quantum-well structures.","PeriodicalId":447328,"journal":{"name":"Fifteenth International Conference on Thermoelectrics. Proceedings ICT '96","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132666900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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