Thermoelectric Cooler Research Articles

Reversible Giant Barocaloric Effect with Broad Working Temperature Range in an Amorphous Ethylene Propylene Diene Monomer.

The barocaloric effect of a solid material is an intense research topic due to its potential application in solid-state refrigeration. Among the proposed candidates, elastic polymers are distinctive because their barocaloric responses are independent from a pressure-induced phase transition which makes it possible to realize a broad working temperature range in principle. However, the barocaloric performance of most elastic polymers diminishes significantly as temperature decreases. In this work, giant and reversible barocaloric effects were observed in a broad working temperature range from 252 to 345 K in an amorphous polymer of ethylene propylene diene monomer, which are much higher than the investigated crystalline and partially crystallized ones. It is demonstrated that the degree of crystallinity can be a key factor responsible for the mobility of polymer chains and the corresponding barocaloric performance at low temperatures. The reversible giant barocaloric effects, broad working temperature regions, low cost, and absence of pressure-transmitting fluid make the ethylene propylene diene monomer attractive for solid-state barocaloric refrigeration.

Strong and efficient bismuth telluride-based thermoelectrics for Peltier microcoolers.

Thermoelectric Peltier coolers (PCs) are being increasingly used as temperature stabilizers for optoelectronic devices. Increasing integration drives PC miniaturization, requiring thermoelectric materials with good strength. We demonstrate a simultaneous gain of thermoelectric and mechanical performance in (Bi, Sb)2Te3, and successfully fabricate micro PCs (2×2mm2 cross-section) that show excellent maximum cooling temperature difference of 89.3K with a hot-side temperature of 348K. A multi-step process involving annealing, hot-forging and composition design, is developed to modify the atomic defects and nano- and microstructures. The peak ZT is improved to ∼1.50 at 348K, and the flexural and compressive strengths are significantly enhanced to ∼140MPa and ∼224MPa, respectively. These achievements hold great potential for advancing solid-state refrigeration technology in small spaces.

Highly efficient multi-layer flexible heatsink for wearable thermoelectric cooling

Flexible thermoelectric cooler (fTEC), which interfaces well with curved human body surface and provides cooling functions, is an emerging candidate for personal thermal management and non-hospitalized medical treatment. Achieving efficient and long-term cooling performance of TEC requires high thermal conductivity and heat diffusion of the hot side, which has yet to achieve. In this study, we design and fabricate a highly thermally conductive and flexible heatsink with a multi-layered structure especially for wearable TEC wristband, which obtains a large temperature drop (8.8 °C) for imitated on-body test and the maxim 13.1 °C temperature decrease in air. Here, we demonstrate that a well-designed functional composite layer, including phase change material, thermally conductive fillers and metal foam, can establish an effective equilibration among cooling performance, thermal management capacity and mechanical property. Particularly, the heatsink with highly thermal conductive skeleton (k ∼ 2.7 W/mK) and effective heat dissipating fins can significantly improve heat conduction and dissipation, which improve the cooling performance by more than 55 %. With the help of theoretical simulation, we propose a promising strategy for heat management on thermoelectric device through a flexible multi-layered structure, paving the way for achieving practical applications of wearable thermoelectric coolers for personal thermal regulation or cooling therapy.

All-solid-state continuous-wave mode-locked Er:Lu2O3 laser at 3 µm

In this paper, we demonstrated stable continuous-wave passively mode-locked operation of an Er:Lu2O3 laser at 3 µm, utilizing a semiconductor saturable absorber mirror (SESAM). By operating the laser in a dry nitrogen environment and utilizing a thermoelectric cooler (TEC) temperature control device to mitigate the thermal effects of Er:Lu2O3 and enhance laser stability, we further compensated for group delay dispersion within the laser cavity through chirped mirrors, an shortest pulse duration of 12.0 ps at a average output power of 150 mW was achieved, which occurred at a center wavelength of 2844 nm, and a pulse repetition rate of 83.5 MHz. Additionally, we achieved a maximum continuous-wave mode-locked output power of 213 mW at an absorbed pump power of 8.3 W, equivalent to a pulse energy of 1.3 nJ. The RF spectrum analysis of the pulse train indicated a high SNR of nearly 70 dB, signifying excellent stability. To the best of our knowledge, This is the first report on the realization of an ultrashort pulse width mode-locked Er:Lu2O3 laser in the mid-infrared band.

Integrated structural and functional analysis of Ba1-xSrxTiO3-Bi0.5Na0.5TiO3 ceramics: Insights into energy storage and electrocaloric performance

This paper reports an extensive investigation on the structural, dielectric, ferroelectric and pyroelectric properties of 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 (x = 0.0, 0.5, 0.6, 0.7) ceramics synthesized via conventional solid-state reaction (SSR) technique. X-ray diffraction data confirms the presence of pure perovskite phase. The variation of lattice parameters with strontium concentration in 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 ceramics were evaluated using the Rietveld refinement of the XRD data. The variation of dielectric permittivity with temperature (ε' ∼ T) shows the diffused phase transition and all the parameters related to the relaxor ferroelectrics (relaxation coefficient, activation energy and freezing temperature) were evaluated. The energy storage properties of the as-prepared ceramics were evaluated using the room temperature PE loop. Amongst the as-prepared ceramics, the composition with x = 0.5 possesses the highest energy storage density of 0.46 J/cm3 with an efficiency of 90 %. The temperature dependent P-E loops were used to study the electrocaloric effect (ECE). The ECE calculations were performed using in-direct method based on Maxwell's thermodynamic relations. A maximum adiabatic temperature change of 0.32 K is achieved at 268 K under a small applied electric field of 25 kV/cm for the ceramic with Sr content x = 0.5. Additionally, electrocaloric responsivity ξmax = 0.13 K mm/kV was also found for the studied ceramics. The above results show that the ceramic 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 with the composition x = 0.5 is a viable lead-free option for application in solid state refrigeration.

PID-Based Temperature Stabilization for Silicon Photomultipliers Using Thermoelectric Cooling Devices

In this paper, we present a temperature stabilization system for Silicon Photomultipliers (SiPMs) using thermoelectric cooling devices controlled by a PID (Proportional-Integral-Derivative) controller. Maintaining a stable temperature for SiPMs and their associated front-end electronics is crucial for achieving consistent gain and noise minimization. Our system employs three CP1881-222 thermoelectric coolers per module and is managed by two ATMega1284p microcontrollers. One microcontroller handles the PID control routine, while the other functions as a TCP/IP client. The temperature is monitored using PT100 sensors connected via MAX31865 RTD converters, ensuring precise measurements. The PID algorithm efficiently corrects temperature deviations, maintaining an error margin of approximately ±0.2◦C. The system has been successfully deployed in the HASC subdetector of CERN’s NA62 experiment, where it maintains the SiPM temperature at 20.5◦C, enhancing the subdetector’s performance. The modular design of our PID controller system allows for adaptability to various experimental setups requiring precise temperature control.

Enhanced Peltier refrigerator using an innovative hot-side heat-rejection mechanism; Experimental study under both transient and steady-state conditions

Peltier refrigerators are an environmentally friendly cooling method, as they require no refrigerants and have no moving parts. However, effective cooling requires optimal-strong heat rejection from the hot side of the Peltier module. This research proposes and tests a self-capillary ultra-thin (0.1 mm) water-attracting coated PVC membrane (SCCP) as an innovative effective heat rejection mechanism. The SCCP cools the hot side of the Peltier module to temperatures even lower than ambient air, without external power. The cooling effect is achieved through the evaporation of a thin water film on the hot surface, driven by capillary action, which releases latent heat. This process can occur under natural or forced convection, both of which are investigated under various voltage and temperature conditions. The SCCP method was compared to traditional heatsinks and showed superior performance, with the hot side temperature being not only cooler than that in heatsink mode but also cooler than the ambient temperature in most cases. Additionally, the SCCP method demonstrated reduced sensitivity to ambient temperature changes, with only a 2–3° increase in the hot side temperature when the ambient temperature was raised by 10°. The findings suggest that SCCP is a promising technique, with further results discussed.

Advances in solid-state and flexible thermoelectric coolers for battery thermal management systems

Advances in solid-state and flexible thermoelectric coolers for battery thermal management systems

Nutrition Temperature and TDS Control System with Fuzzy Logic on Pak Choy Hydroponics (Brassica rapa subsp. chinensis)

Hydroponics is a method of cultivation that does not use soil as a medium, allowing it to be applied in limited spaces such as urban households. One of the vegetable plants that can be grown using hydroponics is pak choy (Brassica rapa subsp. chinensis). To produce healthy pak choy plants that can efficiently absorb nutrients in a hydroponic system, several factors need to be considered, such as the level of Total Dissolved Solids (TDS) in the nutrient solution, nutrient solution temperature, and air humidity in the hydroponic environment. The ideal nutrient solution temperature for hydroponic plants falls within the range of 25-27°C. In this system, a monitoring and control system will be designed to optimize the growth of pak choy plants in a Deep Flow Technique (DFT) hydroponic system. In this system, the nutrient solution temperature will be controlled with a set point of 25°C using an on/off control for a peltier device. To maintain the TDS level at a set point of 1200 ppm in the nutrient solution, fuzzy logic control will be employed, generating timer-based control signals for the nutrient pump A, nutrient pump B, and water pump. The monitoring system will be displayed on an Internet of Things (IoT) dashboard platform, such as ThingSpeak.

Cutting-edge technologies and recent modernization on multifunctional perovskite materials for green energy conversion and spintronic applications

This featured letter summarizes the recent developments in green energy and spintronic technologies based on multifunctional i.e., multiferroic (MF) and magnetoelectric (ME) materials. These are non-toxic materials, find applications in spintronic, non-volatile memory devices, microelectromechanical systems (MEMS), photovoltaics and next generation IC miniaturization devices. Recent studies on MF and ME materials have probed and analyzed significant properties such as evidence of photo-response and significant power conversion efficiency (PCE) of multiferroic-based solar cells (SCs), evidence of electro-caloric effect (ECE) which find usage in non-toxic solid state refrigeration devices, photo- and electro-catalytic activities for green hydrogen generation, magnon-phonon coupling and existence of magnon polarons which can facilitate spintronic device technology and thermal Hall effect and, hybrid nano-generators utilized to empower portable electronic devices. All such applications are comprehensively analyzed in-depth in this letter.

Enhancing pyramid solar still performance using suspended v-steps, reflectors, Peltier cooling, forced condensation, and thermal storing materials

This work aims at enhancing the thermal efficiency of pyramid distiller solar still (PDSS). A modified version (MPDSS) was developed, featuring suspended v-steps on the vertical walls of the distiller. Additionally, the MPDSS was equipped with external reflectors (MPDSS-R) designed to concentrate solar energy, thereby potentially increasing evaporation rates. To further boost the condensation rate, three different methods were implemented and evaluated independently: an external condensation unit integrated with the MPDSS (MPDSS-C), a fixed nano-enhanced thermal storing material (NTSM) within the MPDSS (MPDSS-NTSM), and an installed Peltier device (MPDSS-P). The results indicated that the MPDSS with suspended steps achieved a significant improvement, with a 40 % increase in distillate yield over PDSS. MPDSS with reflectors resulted in a 96 % increase in yield. Moreover, integrating a Peltier device with the MPDSS led to a 148 % boost in distillate yield, while the yields increased by 139 % and 143 % when utilizing the NTSM and the condenser, respectively. Consequently, the optimal performance for the MPDSS was achieved with the combination of reflectors and the Peltier device, attaining a thermal efficiency of 53.96 % and a 148 % improvement in distillate yield. Also, the thermal efficiency of PDSS, MPDSS, MPDSS-R, MPDSS-C, MPDSS-NTSM, and MPDSS-P was 35.46 %, 42.23 %, 46.77 %, 50.89 %, 48.33 %, and 54.67 %, respectively. While the exergy efficiencies ranged from 3.44 % for the PDSS configuration to 4.87 % for the MPDSS-P configuration. Interestingly, the MPDSS-C configuration achieved an exergy efficiency of 4.64 %. The emissions for MPDSS, MPDSS-R, MPDSS-C, MPDSS-NTSM, and MPDSS-P are estimated at 15.03, 14.62, 14.09, 14.30, and 13.79 tons a year, severally. The enviroeconomic parameters were 218, 212, 204, 207, and 200 a year for MPDSS, MPDSS-R, MPDSS-C, MPDSS-NTSM, and MPDSS-P, respectively. Finally, the water expenses are as follows: $0.343/L for the PDSS, $0.292/L for the MPDSS, $0.220/L for the MPDSS-R, $0.082/L for MPDSS-P, $0.105/L for the MPDSS-C, and $0.114/L for the MPDSS-NTSM.

Energy storage efficiency and electrocaloric performances in lead-free Ba0.87Ca0.13(Ti0.9Zr0.1)0.98(Zn1/3Nb2/3)0.02O3 ceramic

Ba0.87Ca0.13(Ti0.9Zr0.1)0.98(Zn1/3Nb2/3)0.02O3 ceramic was prepared using a solid-state reaction method. This work investigates their dielectric, ferroelectric, energy storage, and electrocaloric properties. X-ray diffraction analysis confirms a pure perovskite structure. The dielectric constant reaches a maximum of 9364 at 326 K. Enhanced total energy density, recovered energy density, and energy storage efficiency are observed between 303 K and 363 K. Artificial neural networks (ANNs) are employed for the indirect determination of large ECE and responsivity based solely on measured ferroelectric polarization (P(E,T)). This approach offers rapid and accurate predictions with minimal experimental data, significantly accelerating the characterization of novel electrocaloric materials. The maximum ECE occurs above the Curie temperature (TC) and increases with higher electric fields. The ceramic exhibits significant ECE parameters around TC with a broad electrocaloric temperature span. Various figures of merit, including relative cooling power, refrigerant capacity, and temperature-averaged entropy change, are explored under different electric fields, demonstrating the material's potential for green cooling devices. These figures improve monotonically with increasing field strength. A comprehensive analysis of the field dependence of ΔS (entropy change) confirms the second-order nature of the electric phase transition through master curve analysis. In conclusion, these lead-free ceramics exhibit promising applications in high-performance energy storage devices and solid-state refrigeration technology.

Impact of magnetic, atomic and microstructural ordering on the magnetocaloric performance of powdered NiCoMnSn metamagnetic shape memory ribbons

Co-doped NiMnSn Heusler-type metamagnetic shape memory alloys (MMSMAs) are promising materials for the next-generation solid-state refrigeration systems due to their excellent magnetocaloric performance around the martensitic transformation, which is easily tuneable by slight changes in the alloy composition. An improvement in the thermal efficiency of active magnetic regenerator devices, a key element in magnetocaloric cooling systems, arises by obtaining powdered magnetocaloric alloys that meet technical requirements for their implementation as a feedstock material in the additive manufacturing of 3D-printed heat exchangers. In the present work, powders of Mn-rich NiCoMnSn Heusler-type MMSMAs were obtained from their ribbon form avoiding or minimizing residual stresses, the number of defects and disorder in the crystal lattice and microstructure. Since atomic order and crystallographic structure are crucial in the transformation and magnetic properties of these alloys, a complementary structural analysis of the powders after different heat treatments was performed by powder neutron diffraction. The results show that the cubic austenitic phase of the non-heat-treated melt-spun powder exhibits a highly stressed structure, which leads to an incomplete martensitic transformation and, therefore, to the coexistence of martensitic and austenitic phases at low temperatures. The magnetic structure of the austenite phase was also determined by neutron powder diffraction, obtaining a ferromagnetic coupling between 4a and 4b Wyckoff positions in the samples analysed. It was found that a heat treatment facilitates the martensitic transformation and enables the formation of a pure martensitic phase.The observed changes in the magnetocaloric performance of the powders have been understood in terms of the differently stressed structures and their impact on the martensitic transformation. A fully completed structural transformation leads to a significant increase of the magnetisation change across the martensitic transformation and, consequently, to high values of both a magnetic field induced isothermal entropy change and refrigeration capacity.

Estimation of the Availability of Electrical Energy from the Thermal Energy Extracted by Thermoelectric Modules: Case Study in Monterrey, México

This research proposes the utilization of Peltier modules to convert electrical energy from thermal energy to show its potential as a renewable energy source for residential and commercial application. The study, whose results are presented in this manuscript, was conducted in the city of Monterrey, located in the northeast of Mexico. The energy source was tested and analyzed utilizing a set of statistical metrics and further comparison against experimental test results. The Distrito Tec area in Monterrey city is an academic complex and it was chosen for this study, which consisted of the indirect measurement of the average annual heat energy stored within the buildings’ cement structure. The aim was to obtain the annual accumulated electrical power in Wh per year that Peltier modules could provide in Distrito Tec, which is located in a city with solar irradiation levels above the world average. The proposal in this paper could encourage further investigation regarding this energy that is currently waste heat. More specifically, the results of this research highlight the importance of thermoelectric modules and seek to motivate research to improve their properties and make them more efficient and more viable as well. Thermoelectric modules have the potential to be part of the solution to sustainable development as presented in the United Nations SDG-7—ensure access to affordable, reliable, sustainable and modern energy for all.

Investigation of physical properties of Ba2NdX(X=Nb, Ta)O6 double perovskites for renewable energy applications

Alkali metals at the A site, coupled with rare earth transition metals featuring partly filled 4f and d orbitals at B and B’ sites in A2BB’O6 structure of double perovskites, induce complex d-f electron interactions. Present study explores the rare earth-based double perovskites Ba2NdNbO6 and Ba2NdTaO6, investigating their structural, optoelectronic, magnetic, and thermoelectric characteristics using first principles method. Computational analyses confirm the stable cubic symmetry and ferromagnetic ground state of both compounds. Negative formation enthalpies underline their thermodynamic stability. Spin polarized electronic band structures reveal direct–indirect degeneracy near the Fermi level, dominated by Nd-4f electrons. Optical investigations indicate absorption onset edges at 4.0 eV and significant absorbance peaks in the 6–10 eV range. Furthermore, the investigation into thermoelectric figure of merit reveals capability of Ba2NdNbO6 and Ba2NdTaO6 to efficiently convert heat energy in thermoelectric devices. These findings provide information for potential applications of investigated compounds in thermoelectric (TE) and optoelectronic devices; e.g., in optical absorbers, TE coolers and generators, and photonic devices.

An optimal design of battery thermal management system with advanced heating and cooling control mechanism for lithium-ion storage packs in electric vehicles

Battery thermal management is crucial for the efficiency and longevity of energy storage systems. Thermoelectric coolers (TECs) offer a compact, reliable, and precise solution for this challenge. This study proposes a system that leverages TECs to actively regulate temperature and dissipate heat using transformer oil, known for its excellent thermal conductivity and electrical insulation properties. A thermal management system utilizing liquid immersion cooling was developed, providing both cooling and heating functionalities. The system was tested on a 48 V 26 Ah NMC Li-ion battery pack at charging rates of 0.5C and discharging rates of 0.5C and 1C. Maximum temperatures recorded were: natural convection (NC) at 42.8 °C and 54.9 °C, forced convection (FC) at 33.2 °C and 45.2 °C, and liquid immersion cooling (LIC) at 29.3 °C and 37.7 °C. LIC significantly lowered temperatures compared to NC and FC, while maintaining acceptable misbalance and capacity levels. Additionally, the liquid immersion heating setup effectively heated the battery from −25 °C to 0 °C before charging, demonstrating the system's capability to maintain optimal battery performance.

High-efficiency adaptive temperature control for thermoelectric system based on the OBPPID strategy

Thermoelectric cooler (TEC) is widely used for temperature control in optoelectronics, machinery, biomedicine, and other fields. However, the unstable temperature control over wide ranges and different gradients restricts the efficiency of TEC. To highlight the neural network’s effectiveness in controlling TEC systems, the optimized BPPID (OBPPID) strategy is proposed. In the OBPPID strategy, the factors s̃ and G are decided through formula derivation and the particle swarm optimization (PSO) algorithm, respectively contributing to the backward adjustment and forward propagation of BPPID. The OBPPID solves three issues that the BPPID faces: gradient vanishing of network weights, over-reliance of initial network weights and range constraint of control parameters. The OBPPID and BPPID have been simulated 1000 times to evaluate control performance. The results show that, with random initial network weights, the OBPPID strategy reduces the cost variability of the BPPID strategy from 92 to 17, achieving an 81.52% reduction. Physical tests have confirmed that in the temperature control over wide range and the temperature gradients of 5°C, 20°C, and 80°C, the OBPPID strategy can adaptively adjust the control parameters and provide higher efficiency than PID, BPPID and fuzzy PID strategies for TEC system.

Investigation on the linear cooling method of microfluidic chip based on thermoelectric cooler

Precise temperature regulation is a crucial guarantee for many microfluidic analyses. This study presents a linear cooling method of microfluidic chips based on a single TEC, which can achieve synchronous observation of samples. A numerical model was developed and experimentally verified to analyze the temperature responses under different driving current mechanisms of TEC. Based on simulation and experimental analysis, this study proposes to achieve linear cooling based on TEC driven by polynomial function current mechanism. The implementation process is clarified, and the iterative method to obtain the polynomial function current mechanism is provided and elaborated. Using a commercial TEC, the linear cooling of the microfluidic chip from 25.2 °C to −19.7 °C was successfully achieved through both simulation and experiment. The linear cooling rates ranging from 24 °C/min to 41 °C/min with linearity higher than 0.998 were obtained. Moreover, the influencing factors of linear cooling were discussed. It is found that the temperature of the TEC hot side has a significant impact on the linear cooling of the sample cell, while the impact of nitrogen gas temperature is almost negligible. Results also indicate that both the minimum and maximum cooling rates increase as TE-element length increases and TE-element height decreases.

Efficient roller-driven elastocaloric refrigerator

Elastocaloric cooling has experienced fast development over the past decade owing to its potential to reshape the refrigeration industry. While the solid-state elastocaloric refrigerant is emission-free, the efficiency of the state-of-the-art elastocaloric cooling systems is not sufficient yet to reduce carbon emissions during operation. In this study, we double the coefficient of performance, the most commonly used efficiency metric, via the synergy of material-level advances in TiNiCu and the system-level roller-driven mechanism capable of recovering kinetic energy. On the materials level, a 125% improvement in coefficient of performance is illustrated in TiNiCu compared to NiTi, empowered by the B2-B19 martensitic transformation with improved lattice compatibility and the grain boundary strengthening from the nanocrystalline structure. On the system level, owing to the properly sized angular momentum in rotating parts, 78% work recovery efficiency is reported, transcending the theoretical limit previously unattainable without kinetic energy recovery. This confluence of materials and mechanical innovations propels elastocaloric cooling systems into a new realm of efficiency and paves the way for their practical application.

Temperature-dependent lattice dynamics study on phase stability, martensitic transformation mechanism, and vibrational entropy properties of B2-type Ni–Mn–Ti Heusler alloy

The all-d-metal Ni–Mn–Ti Heusler alloy with its good mechanical properties and colossal caloric effects has attracted significant attention for mechanocaloric refrigeration. However, the phase stability of the B2-type disordered structure at finite temperatures and the physical origin of large phase transformation entropy change in theoretical calculation remain unclear. In view of thermal and strongly anharmonic effects, we combined the first-principles and temperature dependent effective potential calculations to systematically study the phase stability, martensitic transformation mechanism, and vibrational entropy properties of B2 partial disordered structures for Ni8Mn5Ti3 and Ni8Mn6Ti2. Our results showed the austenitic structures of Ni8Mn5Ti3 and Ni8Mn6Ti2 both exhibit antiferromagnetic interaction behaviors at targeted temperatures, resolving the contradiction between previous calculations and experiments. By the analysis of phonon dispersion relations and Helmholtz free energies at low and high temperatures, we provided a deeper explanation for the underlying mechanism of martensitic transformation. Meanwhile, the phase transformation temperatures and vibrational entropy changes were accurately predicted compared with the experiment results. Specifically, we demonstrated that the large vibrational entropy change of Ni–Mn–Ti material originates from the contributions of both the tetragonal distortion ratio and volume change, which provides important theoretical guidance and has great practical significance for designing the solid-state material with large vibrational entropy change in the application of solid-state refrigeration.