Eighteenth International Conference on Thermoelectrics. Proceedings, ICT'99 (Cat. No.99TH8407)
The transient test method used by TE Technology, Inc. requires a small temperature difference to ... more The transient test method used by TE Technology, Inc. requires a small temperature difference to be developed across a thermoelectric module to measure its figure-of-merit, Z. Correction factors associated with radiation, conduction, and convection must then be applied to the measurements to determine the actual Z of the N and P average of the thermoelectric materials comprising the module. The accuracy of these correction factors will affect the accuracy of the Z. Radiation and conduction can be calculated with the same accuracy regardless of the size of the module, but convection is inherently size dependent. Factoring in the temperature dependence for convection is also more complex. Therefore, several different sizes of modules were measured in air and in vacuum. Comparison between the Z measured in vacuum and in air was used to test the validity of convection correlations as applied to thermoelectric modules. Recommendations are made for the best correlation to use in determining the convection correction factor.
Fifteenth International Conference on Thermoelectrics. Proceedings ICT '96
This paper is an introduction and theoretical investigation of the fast-transient cooling charact... more 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 temperaturedependent, 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 steadystate 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 reintroduced which consists of thermally and electrically separating the cold electrode from the TE pellet. This pulse cooling concept was originally conceived over 30 years ago by Reich[1] at the Borg-Warner Research Center.
XVI ICT '97. Proceedings ICT'97. 16th International Conference on Thermoelectrics (Cat. No.97TH8291)
Recent papers [l], have covered the merits of using finite elements to calculate the thermoelectr... more Recent papers [l], have covered the merits of using finite elements to calculate the thermoelectric device performance for steady-state conditions. Likewise, papers [ 3 ] , [4] have covered the use of finite elements to model transient cooling conditions. It remains then to model power generation performance with finite elements and compare that model with various other modeling techniques. Analysis was based on a single pellet for simplification. The pellet was modeled by treating the differential equations as closed form, finite equations across a small section of the pellet. The maiiy sections, or finite elements, comprised the total pellet. Temperature dependent properties were incorporated into the model. The finite element analysis predicted dfferent results than the temperature-averaging techniques as was to be expected. Finite element analysis should be used when critical optimization is required since it is able to determine accurately the nature of the thermoelectric effects of materials whose properties are highly temperature dependent. Averaging schemes, by their very nature, lose modeling information and are less accurate.
Ict 2005 24th International Conference on Thermoelectrics 2005, Jun 19, 2005
Thermoelectric cold plate coolers with fan-cooled heat sinks are sometimes used on bench tops in ... more Thermoelectric cold plate coolers with fan-cooled heat sinks are sometimes used on bench tops in which the cold plate is facing upwards and is parallel with the bench top. The best performance from the cooler is usually achieved when the tubeaxial fan forces air over the heat sink perpendicular to the fin base. The airflow then splits into two streams
The cooling performance of a thermoelectric (TE) couple is modeled from mathematical differential... more The cooling performance of a thermoelectric (TE) couple is modeled from mathematical differential equations via finite-elements with the use of a digital computer. The finite-element model, which incorporates material property dependence on time and temperature, is presented. TE couple transient performance is investigated by applying an on-off current waveform to the model. Results from the model output are compared with
XVI ICT '97. Proceedings ICT'97. 16th International Conference on Thermoelectrics (Cat. No.97TH8291)
There are many applications where theromelectric (TE) coolers can be used effectively as power ge... more There are many applications where theromelectric (TE) coolers can be used effectively as power generators. In fact, where temperatures are less than 500K, TE cooling modules are the best choice for power generation, whether it be from a cost or performance standpoint. The literature available on this subject is scarce and very limited in scope. This paper describes the configuration, limitations and performance of TE coolers to be used as power generators. Also presented are performance curves generated using a new finite element thermoelectric model [1]. This enables the user to design the optimum TE module and select the nearest TE module (normally used for cooling) for this power generation application. A simple process is presented which provides detailed power generation specification (temperatures, watts in, current and voltage out) using the TE module's cooling specifications ∆Tmax, Imax, Vmax, and Qmax).
... Todd M. Ritzer, Paul G. Lau, Andy D. Bogard TE Technology, Inc., 1590 Keane Drive, Traverse C... more ... Todd M. Ritzer, Paul G. Lau, Andy D. Bogard TE Technology, Inc., 1590 Keane Drive, Traverse City, MI 49686 Tel: (616) 929-3966, FAX ... The stresses incurred during this type of test affect both the effectiveness of the nickel diffusion barrier on the TE material and the mechanical ...
Eighteenth International Conference on Thermoelectrics. Proceedings, ICT'99 (Cat. No.99TH8407)
The transient test method used by TE Technology, Inc. requires a small temperature difference to ... more The transient test method used by TE Technology, Inc. requires a small temperature difference to be developed across a thermoelectric module to measure its figure-of-merit, Z. Correction factors associated with radiation, conduction, and convection must then be applied to the measurements to determine the actual Z of the N and P average of the thermoelectric materials comprising the module. The accuracy of these correction factors will affect the accuracy of the Z. Radiation and conduction can be calculated with the same accuracy regardless of the size of the module, but convection is inherently size dependent. Factoring in the temperature dependence for convection is also more complex. Therefore, several different sizes of modules were measured in air and in vacuum. Comparison between the Z measured in vacuum and in air was used to test the validity of convection correlations as applied to thermoelectric modules. Recommendations are made for the best correlation to use in determining the convection correction factor.
Fifteenth International Conference on Thermoelectrics. Proceedings ICT '96
This paper is an introduction and theoretical investigation of the fast-transient cooling charact... more 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 temperaturedependent, 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 steadystate 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 reintroduced which consists of thermally and electrically separating the cold electrode from the TE pellet. This pulse cooling concept was originally conceived over 30 years ago by Reich[1] at the Borg-Warner Research Center.
XVI ICT '97. Proceedings ICT'97. 16th International Conference on Thermoelectrics (Cat. No.97TH8291)
Recent papers [l], have covered the merits of using finite elements to calculate the thermoelectr... more Recent papers [l], have covered the merits of using finite elements to calculate the thermoelectric device performance for steady-state conditions. Likewise, papers [ 3 ] , [4] have covered the use of finite elements to model transient cooling conditions. It remains then to model power generation performance with finite elements and compare that model with various other modeling techniques. Analysis was based on a single pellet for simplification. The pellet was modeled by treating the differential equations as closed form, finite equations across a small section of the pellet. The maiiy sections, or finite elements, comprised the total pellet. Temperature dependent properties were incorporated into the model. The finite element analysis predicted dfferent results than the temperature-averaging techniques as was to be expected. Finite element analysis should be used when critical optimization is required since it is able to determine accurately the nature of the thermoelectric effects of materials whose properties are highly temperature dependent. Averaging schemes, by their very nature, lose modeling information and are less accurate.
Ict 2005 24th International Conference on Thermoelectrics 2005, Jun 19, 2005
Thermoelectric cold plate coolers with fan-cooled heat sinks are sometimes used on bench tops in ... more Thermoelectric cold plate coolers with fan-cooled heat sinks are sometimes used on bench tops in which the cold plate is facing upwards and is parallel with the bench top. The best performance from the cooler is usually achieved when the tubeaxial fan forces air over the heat sink perpendicular to the fin base. The airflow then splits into two streams
The cooling performance of a thermoelectric (TE) couple is modeled from mathematical differential... more The cooling performance of a thermoelectric (TE) couple is modeled from mathematical differential equations via finite-elements with the use of a digital computer. The finite-element model, which incorporates material property dependence on time and temperature, is presented. TE couple transient performance is investigated by applying an on-off current waveform to the model. Results from the model output are compared with
XVI ICT '97. Proceedings ICT'97. 16th International Conference on Thermoelectrics (Cat. No.97TH8291)
There are many applications where theromelectric (TE) coolers can be used effectively as power ge... more There are many applications where theromelectric (TE) coolers can be used effectively as power generators. In fact, where temperatures are less than 500K, TE cooling modules are the best choice for power generation, whether it be from a cost or performance standpoint. The literature available on this subject is scarce and very limited in scope. This paper describes the configuration, limitations and performance of TE coolers to be used as power generators. Also presented are performance curves generated using a new finite element thermoelectric model [1]. This enables the user to design the optimum TE module and select the nearest TE module (normally used for cooling) for this power generation application. A simple process is presented which provides detailed power generation specification (temperatures, watts in, current and voltage out) using the TE module's cooling specifications ∆Tmax, Imax, Vmax, and Qmax).
... Todd M. Ritzer, Paul G. Lau, Andy D. Bogard TE Technology, Inc., 1590 Keane Drive, Traverse C... more ... Todd M. Ritzer, Paul G. Lau, Andy D. Bogard TE Technology, Inc., 1590 Keane Drive, Traverse City, MI 49686 Tel: (616) 929-3966, FAX ... The stresses incurred during this type of test affect both the effectiveness of the nickel diffusion barrier on the TE material and the mechanical ...
Uploads
Papers by Paul Lau