Solar thermoelectric generator and thermoelectric cooler performance:analysis and comparison using a different shape geometry

Thermoelectric devices are one of the technologies used either to generate electricity by applying a temperature difference using thermal energy or as a heating/cooling system by applying an electrical voltage.The number of materials required to produce a product is an important factor in determining its price.Production costs associated with these materials,as well as their availability and quality,play a crucial role in price determination by manufacturers.In this context,a method that employs a uniform volume distribution was implemented.This approach enabled the analysis to focus on other variables,thereby promoting a more precise and relevant evaluation of overall performance.Based on the finite element method,this study investigated the influence of geometric shape,including Rect-leg,Y-leg,Pin-leg and X-leg designs,on the performance of solar thermoelectric generators and thermoelectric coolers.The study was conducted considering the same hot alumina junction surface that receives solar radiation;however,the ef-fective surface,which corresponded to the heat flow area and had a similar area near the exposed surface,varied depending on the chosen leg geometry,thus impacting the heat flux due to the variation in thermal resistance.In the case of a solar thermoelectric generator,the Rect-leg model,having the same effective surface area,presented the lowest heat loss value resulting from convection and radiation in the heat spreader and the hot alumina plate.Under the same conditions,the Y-leg showed the highest value.The Rect-leg design generated,by using thermal and optical concentration,the highest output power of 0.028 and 0.054 W,and efficiency of 3.47%and 4.7%,respectively,whereas the Y-leg generated lower values of 0.006523 and 0.018744 W for power,and 2.83%and 2.71%for efficiency,respectively.In the case of the thermoelectric coolers,the Y-leg generated the highest temperature difference between the hot and cold sides of 67.28 K at an electric current value of 1.8 A,whereas the Rect-leg,Pin-leg and X-leg generated~66.25,~67.02 and~67.19 K at 6.1,2.7 and 2.6 A.

Experimental investigation on operating behaviors of loop heat pipe with thermoelectric cooler under acceleration conditions

An experimental study was carried out in this article to investigate the transient operating performance of a Dual Compensation Chamber Loop Heat Pipe(DCCLHP) with Thermoelectric Cooler(TEC) under acceleration conditions and ammonia was selected as the working fluid.For the purpose of comparison, experimental work was conducted under terrestrial gravity.Sensitivity analysis was performed to explore the effect of several control parameters such as the heat load, acceleration magnitude and TEC assist on the startup and operating performance of the DCCLHP.Experimental results indicate that the DCCLHP can get to a steady-state operation when the heat load changes from 25 W to 300 W under terrestrial gravity.While under acceleration conditions, the DCCLHP can work at a high operating temperature or even fail to operate, which shows the acceleration effect plays a significant impact on the loop operation.The TEC assist with power of 10 W can improve the operating performance and reduce the operating temperature for the case of small heat load and acceleration magnitude.When the acceleration exceeds 3 g at large heat load, the effect of TEC assist on the operation at large heat load can be ignored.

Recent development and application of thin-film thermoelectric cooler

Recently,the performance and fabrication of thin-ilm thermoeletric materials have been jargely enhanced.Based on this enhancement,the thin-film thermoelectric cooler(TEC)is becoming a research hot topic,due to its high cooling flux and microchip level size.To fulfill a thin-film TEC,interfacial problems are unavoidable,as they may largely reduce the properties of a thin-film TEC.Moreover,the architecture of a thin-film TEC should also be properly designed.In this review,we introduced the enhancement of thermoelectric properties of(Bi,Sb)2(Te,Se)3 solid solution materials by chemical vapor deposition,physical vapor deposition and electro-deposition.Then,the interfacial problems,including contact resistance,interfacial diffusion and thermal contact resistance,were discussed.Furthermore,the design,fabrication,as well as the performance of thin-film TECs were summarized.

A Model to Evaluate the Device-Level Performance of Thermoelectric Cooler with Thomson Effect Considered

In this paper,a one-dimensional thermodynamic model was developed to evaluate the device-level performance of thermoelectric cooler(TEC)with the Thomson effect,contact resistance,gap heat leakage,heat sink,and heat load taken into account.The model was generalized and simplified by introducing dimensionless parameters.Experimental measurements showed good agreement with analytical results.The parametric analysis indicated that the influence of the Thomson effect on cooling capacity continued to expand with increasing current,while the effect on COP hardly changed with current.Low thermal contact resistance was beneficial to obtain lower hot-junction temperature,which can even reduce 2 K compared with the electrical contact resistance in the case study.The gap heat leakage was a negative factor affecting the cooling performance.When the thermal resistance of the heat sink was small,the negative effect of heat leakage on performance would be further enlarged.The enhancement of heat load temperature would increase the cooling power of the TEC.For example,an increase of 5 K in heat load can increase the cooling capacity by about 4%.However,once the current exceeded the optimum value,the raising effect on the cooling power would be weakened.The research can provide an analytical approach for the designer to perform trade studies to optimize the TEC system.

A Strategy to Reduce the Peak Temperature of the Chip Working under Dynamic Power Using the Transient Cooling Effect of the Thin-Film Thermoelectric Cooler

The thin-film thermoelectric cooler(TEC)is a promising solid-state heat pump that can remove the high local heat flux of chips utilizing the Peltier effect.When an electric current pulse is applied to the thin-film TEC,the TEC can achieve an instantaneous lower temperature compared to that created by a steady current.In this paper,we developed a novel strategy to reduce the peak temperature of the chip working under dynamic power,thus making the semiconductor chip operate reliably and efficiently.A three-dimensional numerical model was built to study the transient cooling performance of the thin-film TEC on chips.The effects of parameters,such as the current pulse,the heat flux,the thermoelement length,the number of thermoelements,and the contact resistance on the performance of the thin-film TEC,were investigated.The results showed that when a current pulse of 0.6 A was applied to the thin-film TEC before the peak power of the chip,the peak temperature of the chip was reduced by more than 10℃,making the thin-film thermoelectric cooler a promising technology for the temperature control of modern chips with high peak powers.

Achieving Better Super-cooling in a Two-Stage Transient Thermoelectric Device with Constraint-Free Pulse Current by Multi-Objective Optimization

As a promising energy conversion technology,transient thermoelectric device has potential applications in temperature control and refrigeration.The performance is sensitive to the applied current pulse.However,the conventional current pulse is limited to regular current shapes,which cannot achieve the best super-cooling performance.There exist strong coupling effects between the parameters of pulse shape,pulse amplitude,and pulse width.Simultaneous optimization of all the variables involved in a current pulse is a prerequisite to further improve the super-cooling.To bridge this gap,a constraint-free current pulse design concept was proposed in this study,which was successfully validated by a multi-objective optimization method.The results show that,the effective cooling regime and temperature overshoot both exhibit excellent features after optimization.Compared with the current t~0(mostly employed in previous studies),the betterments are improved by 88.33%and 92.13%for the effective cooling regime and the temperature overshoot,respectively.The underlying physics reveals that,the appropriate mediation between Peltier cooling,Joule heating,and Fourier conduction effects by a wave-like irregular current pulse is responsible for the improvement.The Pareto-optimal front found in the optimized current shape is beneficial for scientists and engineers to make an appropriate decision towards specific practical application.

液态金属基柔性可穿戴热电冷却结构及冷却性能优化

为了提高柔性热电冷却器(TEC)的冷却能力,解决液态金属材料的泄漏问题,同时研究热电腿的尺寸、密度和形状对TEC冷却能力的影响.本文将具有液态核心氧化壳结构的Ni-GaIn(掺镍液态金属)和LMPs(液态金属纳米颗粒)引入柔性TEC中,并针对材料的特性,采用“较大的电极”和“三层PDMS”对传统的热电冷却结构进行了改进.采用“大电极”和“三层PDMS”解决了液态金属量大、易泄漏的问题,降低了成本和环境污染,提高了产品可靠性和制造效率.利用有限元分析软件对结构进行了进一步优化,提供了多物理场和多因素影响下的TEC设计方案.与已报道的采用EGaIn互连和传统热电冷却结构的柔性TEC相比,本文制备的两种新型柔性TEC分别具有冷却能力高(7.4℃)和性能稳定(受弯曲变形影响小)的特点.

Diode-pumped single frequency Tm,Ho:YLF laser at room temperature

A diode-pumped single frequcncy Tm,Ho：YLF laser operating at an eye-safe wavelength of 2 μm has been developed. Temperature of the laser crystal was controlled at room temperature with a thermoelectric cooler. The line-width narrowing elements were two solid uncoated fused silica etalons whose thicknesses were 1 and 0.1 mm, respectively. Continuous wave single frequency power of 113 mW was obtained.