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Global reliance on traditional cooling systems is a pressing concern, especially given their substantial energy demands and refrigerant-related greenhouse gas emissions. The need for sustainable cooling solutions is especially urgent in hot and humid regions. This study presents an innovative solution by introducing a compact, solar-driven cooling system that integrates a Desiccant Wheel (DW) and a Thermoelectric Cooler (TEC). This novel combination leverages solar energy to enhance cooling efficiency while reducing environmental impact. The system's performance was tested through experimental methods and non-dimensional analysis, which served to validate the TRNSYS simulation. The simulation included custom components representing the DW and TEC's physical characteristics. Results demonstrated that the system effectively reduces air temperature and humidity to maintain thermal comfort, achieving Coefficients of Performance (COP) of 0.94 and 1.13in Toronto and Vancouver, respectively. A key feature of the system is the heat recovery design, which uses waste heat from the TEC to regenerate the desiccant material, enhancing COP by 68%. Further analysis through TRNSYS simulation explored the system's adaptability to various climate conditions by testing a range of temperatures (26–43°C) and relative humidity levels (30–100%). This analysis identified three operational regions, optimizing the system's application based on environmental conditions. A life cycle assessment determined a Global Warming Potential (GWP) of 0.0172 kg CO 2 per kW of cooling capacity and an Energy Payback Time (EPBT) of 3.34 years. The economic analysis indicated a total system cost of $2719, predominantly due to the DW and TEC components. In conclusion, this research offers a sustainable and efficient cooling system that provides thermal comfort in hot and humid climates, marking a significant advancement in climate control technology. • Evaluation of innovative hybrid cooling for improved indoor climate control. • The validated system boosts COP from 0.56 to 0.94, ensuring thermal comfort. • Heat recovery strategy boosts system efficiency by 68% in diverse climates. • Life cycle assessment shows 0.0172 kg CO 2 per kW of cooling capacity. • The system demonstrates a 3.34-year energy payback, highlighting cost savings. [ABSTRACT FROM AUTHOR]

• LED cooling by thermoelectric cooler integrated microchannel heat sink is proposed. • The relative importance of the factors was revealed by the Taguchi method. • The proposed LED + TEC + WMHS device showed excellent cooling performance. • The LED headlight can be cooled to temperature lower than the coolant temperature. • Cooling system and factor levels for different applications were recommended. Effective thermal management is crucial for light-emitting diodes (LED). Thermoelectric cooler (TEC) and microchannel heat sink (MHS) have been demonstrated to be effective for thermal management of LED. However, neither the combination of these two methods, nor the dominant factors which could be effectively adjusted to control the LED temperature, have been reported. In this study, a cooling device integrating TEC and water-cooled microchannel heat sink (WMHS) is proposed to improve the thermal management of high-power LED headlights. The start-up performance of the proposed device, LED + TEC + WMHS, was evaluated and compared with three different systems, namely LED + WMHS, LED + AHS (air-cooled heat sink), and LED + TEC + AHS. Experimental results have demonstrated the best performance of the LED + TEC + WMHS device. Orthogonal experiments based on the Taguchi method were conducted to reveal dominant factors among four variables, including TEC current, water inlet temperature, water flow velocity, and ambient temperature. The results show that effects of all the factors were significant while the TEC current has most important influence on the performance. The variation of the thermal management performance with the levels of the factors were investigated. The LED temperature was only 60.0 °C even at severe working conditions (T a = 80 °C, T i = 55 °C) and moderate cooling input (I TEC = 2 A, u = 0.49 m/s), indicating great thermal management performance of the proposed method. Choosing a cooling system and adjusting the factor levels for different applications were recommended. [ABSTRACT FROM AUTHOR]

In this work, a new design concept which combines two-stage design with transient supercooling effect is proposed to enhance the maximum temperature drop across thermoelectric coolers (TECs). A three-dimensional, multiphysics, and transient model is used to examine the design effectiveness. Step current pulses with various amplitudes ( P ) and widths ( τ ) are supplied to the two stages of a two-stage TEC in series. The results show that, as compared with the single-stage counterpart, a significant improvement in the maximum cold-end temperature drop (Δ T c ,max ) is observed for the two-stage TEC. Meanwhile, the new design also greatly reduces the temperature overshoot ( T c ,max ) and increases the holding time of supercooling state (Δ t hold ). Subsequently, effects of the pulse amplitude, width, and shape are discussed and two important geometry parameters: the cross-sectional area ratio of p -type leg to n -type leg and the leg length ratio of cold stage to hot stage are investigated. These results confirm that Δ T c ,max , T c ,max , and Δ t hold can be further improved by optimizing the pulse and the geometry parameters. This work provides a feasible cooling approach for some specific cooling targets, such as mid-infrared laser gas sensors or any other semiconductor devices which require a temporary but large temperature drop. [ABSTRACT FROM AUTHOR]

In this work, a new design of thermoelectric cooler (TEC) with variable semiconductor cross-sectional area is proposed to improve its transient supercooling characteristics. Four key evaluation indicators of transient supercooling for the conventional and new designs, including the minimum cold end temperature, maximum temperature overshoot, holding time of transient state, and recovery time ready for next steady-state, are examined and compared by a three-dimensional, transient, and multiphysics model. Two additional effects are observed in the TEC with variable semiconductor cross-sectional area. First, the variable cross-sectional area makes the thermal circuit asymmetric, so that Joule heat is preferentially conducted toward to the end with a larger cross-sectional area. Second, more Joule heat is produced close to the end with a smaller cross-sectional area. The present simulations find that these two effects can be utilized to achieve the desired evaluation indicators by changing the cross-sectional area ratio of hot end to cold end. When a lower cold end temperature, a smaller temperature overshoot, and/or a longer holding time are/is required, a larger cross-sectional area at the cold end is recommended. However, to achieve a shorter recovery time, a smaller cross-sectional area at the cold end is needed. [ABSTRACT FROM AUTHOR]

The objective of this work is to examine the parameter sensitivity and optimize the cooling performance of two-stage thermoelectric cooler (TEC). Firstly, a multiphysics model is used to investigate the effects of geometry parameters and applied currents on the performance of a two-stage TEC. Specially, cross-sectional area ratio of the p-type leg to the leg pair χ and height ratio of the cold stage leg to the two stage legs δ are explored, which have never been investigated in previous studies. Secondly, a simplified conjugated-gradient method is coupled into the multiphysics model to optimize the four key geometric parameters and two applied currents supplied to hold and cold stages, for seeking the maximum cooling capacity. The results of individual parameter analysis mainly show that the optimal χ does not depend on the geometric structure and applied currents of TEC, while it is only determined by the p-type and n-type semiconductor materials. The height ratio δ always plays the role to adjust the temperature between the cold and hot stages, resulting in that the both stages could operate at the proper temperature differences matching with their respective applied current. The optimization results show that the maximum cooling capacity Q c,c at Δ T = 0, 20, 40, and 60 K is enhanced by 19.62%, 21.30%, 25.49%, and 43.83%, respectively, as compared with the initial design. When Δ T increases from 0 K to 40 K, the change for each parameter in the optimal set is not larger than 1.8%, indicating that once the optimal design is obtained at a specific Δ T , it can be safely used at any other Δ T . [ABSTRACT FROM AUTHOR]

Energy crisis and environment deterioration are two major problems for 21st century. Thermoelectric device is a promising solution for those two problems. This review begins with the basic concepts of the thermoelectric and discusses its recent material researches about the figure of merit. It also reports the recent applications of the thermoelectric generator, including the structure optimization which significantly affects the thermoelectric generator, the low temperature recovery, the heat resource and its application area. Then it reports the recent application of the thermoelectric cooler including the thermoelectric model and its application area. It ends with the discussion of the further research direction. [ABSTRACT FROM AUTHOR]

• A battery thermal management system that uses fins to enhance the combination of thermoelectric cooler and phase change material was established. • Compared the effects of four thicknesses of fins on the thermal management performance. • It was proved that adding fins is beneficial to improve the thermal management performance under three working conditions. • The influence of the input current on the cooling power and COP of TEC was analyzed. In this study, a hybrid active & passive BTMS(Battery Thermal Management System) that uses fins to enhance the combination of TEC(Thermoelectric Cooler) and PCM(Phase Change Material) is shown. The cold side of the TECs produces a cooling effect, which is used to cool the PCM and prevent it from melting completely in a short time, thereby extending the temperature control time. Fins are used to transfer the heat of the PCM to the cold side of the TECs, and effectively cool the batteries at high temperatures. The effects of different fin thicknesses (2 mm-8 mm) and different TEC input currents (1A-6A) on thermal management performance were analyzed by numerical simulation. The results show that the temperature control time was prolonged by 12% when the fins were increased from 2 mm to 8 mm, but the temperature difference increased by 13.7%. When the current changed from 1A to 6A, the temperature control time increased by 87.42%, but the temperature difference and COP became worse. Comprehensive analysis of temperature control time, temperature difference, COP, 4 mm fin thickness, and TEC input current of 3A were optimal for the model in this paper. [ABSTRACT FROM AUTHOR]

Highlights: [•] A complete three-dimensional TEC transient model was proposed. [•] The model couples heat conduction and electric conduction. [•] Dynamic behaviors are studied at extensive operating conditions. [•] Temperature-dependent material properties have strong effect on dynamic behaviors. [ABSTRACT FROM AUTHOR]

Abstract: The optimum design of thermoelectric devices (thermoelectric generator and cooler) in connection with heat sinks was developed using dimensional analysis. New dimensionless groups were properly defined to represent important parameters of the thermoelectric devices. Particularly, use of the convection conductance of a fluid in the denominators of the dimensionless parameters was critically important, which leads to a new optimum design. This allows us to determine either the optimal number of thermocouples or the optimal thermal conductance (the geometric ratio of footprint of leg to leg length). It is stated from the present dimensional analysis that, if two fluid temperatures on the heat sinks are given, an optimum design always exists and can be found with the feasible mechanical constraints. The optimum design includes the optimum parameters such as efficiency, power, current, geometry or number of thermocouples, and thermal resistances of heat sinks. [Copyright &y& Elsevier]

Abstract: In this study, numerical simulation of transient thermal behavior of thermoelectric coolers is attempted based on a non-uniform-current model. In the present model, the thermoelectric cooler is divided into seven blocks, including aluminum plates, ceramic plates, and P-type and N-type thermoelectric elements. Numerical solution for three-dimensional distributions of electric voltage and electric current vectors in the thermoelectric cooler are firstly obtained. The obtained distribution of the electric current vectors is introduced into energy equation for the solutions of the transient thermal behavior of thermoelectric coolers. A parametric study is performed to investigate the effects of the influential parameters including applied electric current, heat transfer coefficient on the ceramic plate of hot end, heat transfer coefficient on surfaces of the P-type and N-type elements, height of the P-type and N-type elements, and cooling load per unit area. To verify the numerical predictions, experimental data have been presented for variation of temperatures of both cold and hot ends. It is observed that the numerical predictions closely agree with the experimental temperature data. [Copyright &y& Elsevier]

• Detailed review of thermoelectric geometry and structure optimization are presented. • Thermal stress studies on thermoelectric generators and coolers are reviewed. • Three-dimensional and multi-objective optimization studies are reviewed. • Future research directions on thermoelectric geometry optimization are presented. Thermoelectric geometry and structure optimization are vital research areas which are being explored extensively in recent years due to significant performance enhancement achieved. However, the lack of a single review paper on this key area is a huge gap identified. Therefore, this review presents a first of its kind in-depth analysis of the start of art in thermoelectric geometry and structure optimization. The four main parameters including leg length or height, cross-sectional area, number of legs and leg shape which are paid attention to during optimization of thermoelectric geometry are discussed in detail. In addition, a review of the different thermoelectric structure available in literature such as flat plate, annular, segmented, cascaded, corrugated, concentric, linear, flexible and micro thermoelectric generators and coolers is presented. Furthermore, special attention is paid to both electrical and mechanical performance enhancement obtainable from thermoelectric geometry and structure optimization. A review of thermal stress optimization is presented alongside other optimization including contact resistance, heat pipe, pulsed heating and cooling. Geometry and structure optimization methods including three-dimensional finite optimization and multi-objective optimization are discussed in detailed and the most significant results obtained from the literature review are presented. This comprehensive review will be a valuable and essential reference literature on all issues relating to thermoelectric geometry and structure optimization. [ABSTRACT FROM AUTHOR]