Commercial Thermoelectric Cooler Research Articles

Distributed and localized cooling with thermoelectrics

G. Jeffrey Snyder is a Professor of Materials Science and Engineering at Northwestern University in Evanston Illinois. His interests are focused on engineering of electronic and thermal properties, and he is well known for his work on thermoelectric materials. He has developed new methods of electron band structure engineering and microstructure engineering of thermal and electrical properties of complex materials. His interdisciplinary approach stems from his background in solid state chemistry at Cornell University and the Max Planck Institute for solid state research, applied physics at Stanford University, and thermoelectric materials and device engineering at NASA/Jet Propulsion Laboratory and California Institute of Technology (Caltech).

Effective behaviors of anisotropic thermoelectric composites containing ellipsoidal inclusions

Abstract Thermoelectric (TE) materials are well-known to be able to directly convert heat into electricity. In developing high-performance TE materials, the inclusions are often used to enhance its energy conversion efficiency. In this paper, an effective medium model is developed to evaluate the effective behaviors of anisotropic TE composites containing multiple inclusions. First, the non-linearly coupled TE governing equations are solved by defining two generalized field variables. Then, the effective TE properties are derived based on the fundamental idea of Eshelby’s theory and the self-consistent method, and the explicit solutions for some particular inclusion cases are given. Furthermore, the presented models are validated by finite element simulations and the effects of inclusion properties and inclusion shapes on the performance of the TE composite are discussed. The results show that specific inclusions may greatly boost the TE figure of merit of the composite. Furthermore, we apply the presented model to a commercial thermoelectric cooler(TEC) module, and find that the cooling performance can be enhanced by as much as 22.79% by inserting voids. The presented research thus sheds considerable insight into the performance evaluation of effective behavior of TE composites and may pave a new way of boosting the performance of TE devices.

Effects of thermal and electrical contact resistances on the performance of a multi-couple thermoelectric cooler with non-ideal heat dissipation

Abstract The influence of adverse working conditions on the cooling performance of thermoelectric cooling chips is numerically studied in this work. A three-dimensional steady-state physical and mathematical model that considers thermoelectric coupling is developed for a commercial thermoelectric cooler (TEC) of bismuth telluride (Bi2Te3). An imaginary non-uniform temperature distribution with the variable maximum excess temperature ( θ m ) and scale of high temperature region ( ω ) are used as boundary conditions for the hot end of the chip to simulate the effect of a poor heat dissipation. The electrical contact resistance R e , c ( = M × r e , c ) and the thermal contact resistance R k , c ( = N × r k , c ) are set at the interface layer of different materials with two magnifying factors (M and N) to simulate varying degrees of interfacial effects from defective contacts. The numerical results show that of all adverse factors, electrical contact resistance may cause the most severe reduction in a TEC's performance. Further studies demonstrated that M has a far greater effect on the performance curve ( Q c vs . I and C O P v s . I ) than the other three parameters (N, θ m , ω ) in both Q c m a x and COP max modes. In addition, the phenomenon of drift of the optimal current is found and discussed.

A Full-Solid-State Humidity Pump for Localized Humidity Control

Summary Humidity management is essential and widely needed in various fields. Traditional moisture removal technologies are mostly based on cooling condensation or desiccant dehumidification. These methods come with inherent defects of energy efficiency and are bulky and complex for small-space humidity-control applications. Here, we demonstrate a full-solid-state humidity pump using the advantages of commercial thermoelectric coolers and silica gel materials. Silica gel is coated on the surface of heat sinks to minimize contact thermal resistance between the material and heat source while maintaining enough heat and mass transfer area between the desiccant and the air. The humidity pump device exhibits 0.61 g W−1 h−1 humidity transfer efficiency, corresponding to a humidity transfer rate of 28.38 g h−1. The proposed device neither uses refrigerant nor introduces liquid water. It opens up the possibility of use in localized humidity control applications with higher efficiency and a wider ambient temperature range than traditional technologies.

Analysis and Experimental Investigation of Optimum Design of Thermoelectric Cooling/Heating System for Car Seat Climate Control (CSCC)

The optimum design of a thermoelectric system for application in car seat climate control has been modeled and its performance evaluated experimentally. The optimum design of the thermoelectric device combining two heat exchangers was obtained by using a newly developed optimization method based on the dimensional technique. Based on the analytical optimum design results, commercial thermoelectric cooler and heat sinks were selected to design and construct the climate control heat pump. This work focuses on testing the system performance in both cooling and heating modes to ensure accurate analytical modeling. Although the analytical performance was calculated using the simple ideal thermoelectric equations with effective thermoelectric material properties, it showed very good agreement with experiment for most operating conditions.

Numerical modeling of the thermoelectric cooler with a complementary equation for heat circulation in air gaps

AbstractIn this paper, a numerical model is developed by combining thermodynamics with heat transfer theory. Taking inner and external multi-irreversibility into account, it is with a complementary equation for heat circulation in air gaps of a steady cooling system with commercial thermoelectric modules operating in refrigeration mode. With two modes concerned, the equation presents the heat flowing through air gaps which forms heat circulations between both sides of thermoelectric coolers (TECs). In numerical modelling, a TEC is separated as two temperature controlled constant heat flux reservoirs in a thermal resistance network. In order to obtain the parameter values, an experimental apparatus with a commercial thermoelectric cooler was built to characterize the performance of a TEC with heat source and sink assembly. At constant power dissipation, steady temperatures of heat source and both sides of the thermoelectric cooler were compared with those in a standard numerical model. The method displayed that the relationship betweenΦfand the ratioΦc′/Φc$\varPhi_{{\text c}}'/\varPhi_{{\text c}}$was linear as expected. Then, for verifying the accuracy of proposed numerical model, the data in another system were recorded. It is evident that the experimental results are in good agreement with simulation(proposed model) data at different heat transfer rates. The error is small and mainly results from the instabilities of thermal resistances with temperature change and heat flux, heat loss of the device vertical surfaces and measurements.

A Method for In-Situ, Total Ionising Dose Measurement of Temperature Coefficients of Semiconductor Device Parameters

This work presents and discusses a test method developed to allow the measurement of total ionising dose induced changes in temperature effects on electronic devices for space and nuclear applications. Two demonstration experiments testing commercial PMOS transistors were performed, using different methods of I-V curve measurement. The temperature of the devices during irradiation was controlled precisely using a commercial thermoelectric cooler. A programmable temperature controller combining digital and analogue control techniques was developed for this project. The experimental results allow better insight into the field of temperature sensitivity of PMOS devices.

Performance Prediction of Commercial Thermoelectric Cooler Modules using the Effective Material Properties

This work examines the validity of formulating the effective thermoelectric material properties as a way to predict thermoelectric module performance. The three maximum parameters (temperature difference, current, and cooling power) of a thermoelectric cooler were formulated on the basis of the hot junction temperature. Then, the effective material properties (Seebeck coefficient, electrical resistance, and thermal conductivity) were defined in terms of the three maximum parameters that were taken from either a commercial thermoelectric cooler module or the measurements. It is demonstrated that the simple standard equation with the effective material properties predicts well the performance curves of the four selected commercial products. Normalized parameters over the maximum parameters were also formulated to present the characteristics of the thermoelectric coolers along with the normalized charts. The normalized charts would be universal for a given thermoelectric material.

Soliton compression of the erbium-doped fiber laser weakly started mode-locking by nanoscale p-type Bi2Te3 topological insulator particles

We demonstrate the nanoscale p-type Bi2Te3 powder-based saturable absorber-induced passive mode-locking of the erbium-doped fiber laser (EDFL) with sub-picosecond pulsewidth. Such a nanoscale topological insulator powder is obtained by polishing the bulk p-type Bi2Te3 in a commercial thermoelectric cooler (TE cooler). This is then directly brushed onto the end-face of a single-mode fiber patchcord, to avoid any mis-connecting loss caused by laser beam divergence, which can result in a mode-locked pulsewidth of 436 fs in the self-amplitude modulation mode of a TE cooler. To further shorten the pulse, the soliton compression is operated by well-controlling the group delay dispersion and self-phase modulation, providing the passively mode-locked EDFL with a pulsewidth as short as 403 fs.

The Thomson effect and the ideal equation on thermoelectric coolers

Abstract The formulation of the classical basic equations for a thermoelectric cooler from the Thomson relations to the non-linear differential equation with Onsager's reciprocal relations was performed to basically study the Thomson effect in conjunction with the ideal equation. The ideal equation is obtained when the Thomson coefficient is assumed to be zero. The exact solutions derived for a commercial thermoelectric cooler module provided the temperature distributions including the Thomson effect. The positive Thomson coefficient led to a slight improvement on the performance of the thermoelectric device while the negative Thomson coefficient led to a slight declination of the performance. The comparison between the exact solutions and the ideal equation on the cooling power and the coefficient of performance over a wide range of temperature differences showed close agreement. In conclusion, the Thomson effect is small for typical commercial thermoelectric coolers and the ideal equation effectively predicts the performance.

Analysis of thermoelectric cooler performance for high power electronic packages

Abstract In this paper, an analysis of thermoelectric cooler (TEC) performance is conducted for high power electronic packages such as processors. Based on the TEC module parameters, two sets of analytical solutions for TECs in system constraints are derived for the junction temperature T j at a fixed cooling power Q c , and for Q c at a fixed T j , respectively. As against the iterative procedure often reported in literature, the major advantage of the present analytical method lies in the fact that the solutions can be obtained without resorting to the pellet thermoelectric parameters and geometric details. Two cooling scenarios, the processor test and the processor cooling under end-user conditions, are analyzed based on the present analysis models for two commercial TECs with high cooling power capacities nominal. Analytical results show that significant thermal enhancements are achievable based on optimized currents and cooling configurations. The validation of the present analysis is also conducted through experimental measurements and comparison with previous solutions.

A computer-aided design tool to facilitate the realisation of cooling systems

In electronic products that require cooling management, the cumbersome task of finding suitable commercial thermoelectric cooler modules and determining their performances in the designs can often slow down the product realisation process. This paper presents a framework and an internet-enabled computer-aided design tool to assist designers in cooling system development. Based on user design specifications, the product design facility can estimate the required heat load, determine the required component characteristics, search for appropriate parts from different vendors and analyse the thermal performances of user-selected modules in cooling system designs. These facilities will allow designers to develop Thermoelectric Cooling (TEC) systems in less time using the latest and most suitable thermoelectric components available on the market.

Development of a multi-vendor software to size and select TEC

The task of finding suitable commercial thermoelectric coolers (TECs) and determining their configurations in the cooling system designs can be a difficult and cumbersome iterative process due to the varieties of product ranges available from different vendors. This paper presents the development of a computer-aided tool, which is interactive and platform-independent, to assist the designers in the search for appropriate TECs from different manufacturers. Based on the user design specifications, the software can estimate the required heat load, determine the TEC requirements, search for appropriate TECs from various vendors, and analyze the thermal performances of the cooling system designs using different selected TECs.

Thermal analysis of laser diode module by an equivalent electrical network method

An equivalent electrical network method is presented in this paper to analyze the cooling characteristics of a laser diode module (LDM). And a modified equivalent model of a thermoelectric cooler (TEC) with an adjunctive thermal resistance and a contact resistance is proposed. The performance of a commercial TEC has been simulated. The thermal analysis of a LDM incorporated with a TEC has been performed by using an equivalent circuit model of the LDM. In the analysis the change of LD current, TEC current, and the ambient temperature are all considered. It shows that the equivalent circuit approach is an offective tool for the qualitative analysis of TEC and LDM.

Screened exchange LDA determination of the ground and excited state properties of thermoelectrics:Bi2Te3

Predicting the performance of thermoelectric materials requires precise knowledge of the Fermi surface and near-lying electronic structures. While ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$ is a major constituent of the active layers in commercial thermoelectric coolers, ab initio electronic structure theory heretofore has failed to reproduce the measured experimental band gap. Herein, we report self-consistent screened-exchange local density approximation (sX-LDA) calculations for the electronic structure of ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$, using the precise full-potential linearized augmented plane-wave method including self-consistent spin-orbit coupling. Our results include (i) a predicted sX-LDA band gap of $154\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$, in excellent agreement with the zero temperature extrapolated experimental value of $162\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$; this value may be compared with previously reported LDA and generalized gradient approximation values of 61 and $50\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$, respectively; and (ii) significant improvement in the effective masses of electrons, with respect to experiments and previous calculations.

EPerformance and Configuration Improvements for a Thermoelectric Dehumidifier

This study presents the dehumidification rates of a thermoelectric dehumidifier using different heat sinks. The performance of a commercial thermoelectric cooler used as a dehumidifier was investigated. A substantial improvement on dehumidification rate was observed when both the fin configurations on cold end and hot end were optimized. In the consideration of space compactness, the extruded bonded-fins and a fan served as the hot-end heat sink was replaced by a vertical flat-plate. To enhance the heat dissipation rate for this flat-plate, optimization technique is applied first to obtain the proper thickness and the surface of plate was then anodized to increase the radiant emissivity. In this study, the cool condensate resulting from the dehumidification process inside the cabinet is guided through a drain hole via a wetted cotton cloth, which is also spread over the plate surface. The evaporation cooling on plate surface can further enhance its heat dissipation and obtain a better dehumidification performance.

Measurement of Microkelvin Temperature Differences in a Critical-Point Thermostat

The density of a pure fluid near its critical point is extremely sensitive to temperature gradients. In the absence of gravity, this effect limits the fluid's homogeneity. For example, at 0.6 mK above the critical temperature, the microgravity experiment Critical Viscosity of Xenon (CVX) can allow temperature differences no larger than 0.2 μK, corresponding to a gradient of 10−5 K·m−1. The CVX thermostat, which consists of a thick-walled copper cell contained within three concentric aluminum shells, was designed to achieve such a small temperature gradient. However, asymmetries not included in the thermostat's model could degrade the thermostat's performance. Therefore we measured the temperature gradient directly with a miniature commercial thermoelectric cooler consisting of 66 semiconductor thermocouples. We checked the results with a half-bridge consisting of two matched thermistors. The measurement was made along a thin-walled stainless-steel cell whose conductance was much lower than that of the copper cell, thus “amplifying” the temperature differences by a factor of 60. When the thermostat was controlled at a constant temperature, the steel cell's static temperature difference was 5±1 μK. (The value inferred for the copper cell is 0.08 μK.) Ramping the thermostat's temperature at a rate of 1 × 10−5 K·s−1 increased the temperature difference to 0.36 mK. These results demonstrate the feasibility of achieving extremely low temperature gradients.