Commercial Thermoelectric Modules Research Articles

Intercalation of V2O5 and Polypyrrole into a Graphene Oxide Layer: A Hybrid Multifunctional Photothermal Structure for Efficient Solar Evaporation, Water Purification, Disinfection, and Power Production.

Development of a hybrid multifunctional photothermal structure with multifunctional capabilities is deliberated as an effective approach for harvesting abundant solar energy for sustainable environmental applications. Achieving enhanced solar to thermal conversion efficiency utilizing a suitably designed, environmentally compatible thermal management structure however remains a significant challenge. Herein, we report the intercalation of V2O5 and polypyrrole into a graphene oxide layer to design a hybrid photothermal assembly (PPy-V2O5-GO) and its multifunctional proficiencies. The hybrid photothermal structure demonstrated synergistic photothermal conversion, buoyant porous structure sustaining water transmission, and efficient steam release. V2O5 and polypyrrole-intercalated optimized graphene oxide structure attained an evaporation rate of 1.9 kg m-2 h-1 with a conversion efficiency of 92% under 1 sun solar radiation. At maximum, the assembly's surface temperature hit 64 ± 2 °C, suggesting its suitability as a solar water purifier. Outdoor experiments suggest the evaporator assembly's capability to accumulate a total output of 15 kg m-2 over a single day. Cell viability investigations revealed strong antimicrobial properties of PPy-V2O5-GO against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria, eliminating nearly all under 1 sun, making it a potential candidate for photothermal therapy. Furthermore, when combined with a commercial thermoelectric module, the framework displayed exceptional photothermal conversion efficiency, hinting at its potential for electrical power generation. The integration of PPy-V2O5-GO with a Bi2Te3-based thermoelectric module significantly boosted the thermoelectric generator's performance, offering an enhanced power output of 2.8 mW and a high power density of 1.24 mW/cm2, making them suitable for off-grid or remote-area application. Overall, the PPy-V2O5-GO photothermal assembly's stability, lack of leaching, effectiveness in producing pure water from seawater, antimicrobial efficacies, and recyclability make it an excellent choice for sustainable water treatment and power generation.

Experimental study on a novel split thermoelectric cooler of big temperature difference for combined cooling and heating supply

The improvement in maximum temperature difference is very important for thermoelectric cooler potential applications under severe and complex conditions. Currently, the maximum temperature difference of commercial single-stage thermoelectric modules represented is usually below 70 K and the energy efficiency is not high. In this paper, 12 kinds of split thermoelectric modules are developed according to different semiconductor and connector structures, and their performance is compared by experiments. The results show that the temperature difference of novel split thermoelectric cooler can exceed 200 K, which is more than 180 % higher than the currently commercial module (70 K), and it also has good performance under high ambient temperature. The new thermoelectric module can achieve the application of cold and hot ends energy on long-distance different occasions and has a module coefficient of performances of 2.68 and 1.29 under temperature differences of 57.43 K and 197.73 K, respectively. Meanwhile, a new asymmetric design method for independent control of hot and cold end temperatures is presented. It can achieve independent heat flux density design for cold and hot ends, and its performance can be further enhanced by regulating the temperature of connector.

Self-assembled Cu doped NiO loaded reduced graphene oxide: Multifunctional photothermal framework for interfacial water evaporation, disinfection and power generation

Development of self-assembled multifunctional photothermal materials is considered as reconciliation between solar energy harvesting and sustainable energy and environmental applications. Herein, we report strategically designed self-assembled Cu-doped-NiO nanoparticles loaded-rGO (rGO-Cu-NiO) framework. The self-assembly exhibited synergistic photothermal conversion, floatable porous structure for efficient capillary action enabling water transmission and quick steam escape pathways. The optimized rGO-Cu-NiO framework achieved interfacial water evaporation rate of 1.47 kgm−2h−1 with 92% conversion efficiency under 1Sun illumination. Maximum surface temperature of the framework displays 74 °C under 2Sun irradiation, making it highly feasible to be implemented as solar water purifier. Cell viability examination indicated the superior antimicrobial properties, making it a promising candidate for photothermal therapy application. Moreover, the self-assembled rGO-Cu-NiO framework integrated with the commercial thermoelectric module shows outstanding photothermal conversion efficiency to envisage its ability towards electrical power generation. Impressively, the amalgamation of the framework with the Bi2Te3 based commercial thermoelectric module proficiently reinforce the performance of the thermoelectric generator by offering an enhanced power output of 3.91 mW and appreciably high power density of 0.311 mW/cm2. Overall, the excellent stability, no photo-leaching, effectiveness to produce pure water from seawater, antimicrobial properties, recyclability, make rGO-Cu-NiO a perfect epitome of sustainable water treatment and power generation application.

Comparative analysis of numerical models of plate-fin heat sinks with forced convection for thermoelectric energy generation

Plate-fin heat sinks under forced convection are economical dissipaters employed in a wide variety of sectors. These types of heat sinks are commonly used in power generation by means of commercial thermoelectric generator modules. The design of the heat sink is a key factor in these power generation systems since it greatly affects the efficiency of the direct conversion from heat into electrical energy. Here, we analyse several numerical models of plate-fin heat sinks under forced convection with and without air flow bypass. The predictions of both hydraulic and thermal parts of these models are compared with our own experimental data. Results reveal that Lindstedt and Karvinen model (2012) is the more accurate one, with discrepancies with respect to measurements below 12% for most of the cases studied.

Experimental study of an optical concentrated solar thermoelectric power generator

The commercial thermoelectric modules become more and more efficient in terms of mechanical reliability, cooling capacity (in Peltier mode), power generation (in Seebeck mode), tolerable thermal conditions and so on. In this paper a portable optical concentrated solar thermoelectric generator is proposed, designed, tested, and evaluated based on a single UTX15-288-F2 module in both transient and steady-state conditions. A 30 cm diameter optical concentrator is employed to concentrate the solar power on one side of thermoelectric. Due to the low scale of the generated power, the active cooling methods for the other side of the module is not desirable and economical. That is why the boundary condition of the other low temperature side of thermoelectric is just natural convection by a heatsink under shadow condition. The aim of this case study is to clarify the UTX15-288-F2 module behavior under the mentioned conditions for possible portable micropower applications. Generated power, solar radiation, temperature of both side of the module and ambient conditions are measured during the experiments, reported, discussed, and analyzed.

Additive fabrication and experimental validation of a lightweight thermoelectric generator

We develop a thermoelectric generator based on catalytic combustion and operating in the low power range (up to 10 W). Considering the target of small-scale thermoelectric generators, the additive technique was chosen as an enabling technology to customize the different parts of the presented device. The generator consists of a hexagonal shaped combustion chamber coupled to commercial thermoelectric modules, water-cooled at the cold side. Thanks to the components design, heat transfer across each part of the system is properly driven enhancing the thermal management of the system. Moreover, in order to improve the overall efficiency, exhausts outlet is designed to promote heat recovery. The generator is characterized achieving an electrical power output close to 9 W in continuous regime, with an overall efficiency of 3.55%. The compact size, the light weight, the simple design and the reliability in continuous operating conditions are all promising features of the device described. Furthermore, the materials chosen for the device can suggest a way to fabricate cheaper heat exchangers, actually one of the main costs of the device development.

Hydrophilic candle wastes microcapsules as a thermal energy storage material for all-day steam and electricity cogeneration

On-site reclamation of freshwater from seawater is urgently desired to combat freshwater scarcity, in which solar-driven interfacial evaporation has been realized as a promising strategy. However, solar desalination has been facing the negative influence of intermittent solar radiation alternating day and night; thus, incorporating a material recommended as thermal energy storage material into the photoabsorber is a profitable strategy to supply the heat for 24-h steam generation. Herein, graphene oxide (GO) was incorporated with the candle waste to store the thermal energy and encapsulated into the SiO2 shell to prevent the leakage of the paraffine wax and enhance the membrane hydrophilicity. A collaborative device including the evaporator and a commercial thermoelectric (TE) module was designed for steam-electricity cogeneration which exhibits a simultaneous evaporation rate of 1.09 kg m−2 h−1 and power density of 6.8 W m−2 under one sun irradiation. Besides, the paraffin component can store thermal energy, enabling the device to maintain a certain steam and electricity cogeneration of 0.35 kg m−2 h−1 and 2.8 W m−2 after light-off. This work may provide a cost-effective strategy for the fabrication of potential photoabsorbers from environmental wastes for all-day water evaporation and power cogeneration device to mitigate freshwater and electricity shortages.

Characterization of commercial thermoelectric modules for precision heat flux measurement.

In this article, we present a cost-effective approach to the precision measurement of heat flux using commercial thermoelectric modules (TEMs). Two different methods of measuring heat flux with TEMs are investigated, namely, passive mode based on the Seebeck effect and active mode based on the Peltier effect. For both modes, a TEM as a heat flux meter is calibrated to show a linear relation between the voltage across the TEM and the heat flux from 0 to ∼450Wm-2. While both modes exhibit sufficiently high sensitivities suitable for low heat flux measurement, active mode is shown to be ∼7 times more sensitive than passive mode. From the speculation on the origin of the measurement uncertainty, we propose a dual TEM scheme by operating the top TEM in passive mode while its bottom temperature maintains constant by the feedback-controlled bottom TEM. The dual TEM scheme can suppress the sensitivity uncertainty up to 3 times when compared to the single-TEM passive mode by stabilizing the bottom temperature. The response time of a 15 × 15mm2 TEM is measured to be 8.9 ± 1.0s for heating and 10.8 ± 0.7s for cooling, which is slower than commercial heat flux meters but still fast enough to measure heat flux with a time resolution on the order of 10s. We believe that the obtained results can facilitate the use of a commercial TEM for heat flux measurement in various thermal experiments.

Design and characterization of a novel finned tubular thermoelectric generator for waste heat recovery

Most commercial thermoelectric modules have a flat design that complicates their integration into gas/liquid thermoelectric conversion systems. The aim of the present study is to develop a robust, compact, and cost-effective design that is easier to incorporate into gas/liquid thermoelectric energy recovery systems. The description entails a novel finned tubular thermoelectric generator (FTTEG) prototype with three distinguishing characteristics: (i) quadratic-profiled thermoelectric legs arranged axially, (ii) a resin-based semi-rigid assembly, and (iii) annular heat exchange fins.Module properties such as contact resistance, resin properties and heat exchanger performance were investigated using a numerical model developed with ANSYS-Fluent. Exchanger thermal efficiency was thus found maximal at a fin spacing of 2–3 mm and a fin height of 11–13 mm at the conditions of operation defined.A test bench was built to evaluate the ability of the module to generate electrical power from hot water against forced ambient air. An output power of 16 mW at 600 mV open-circuit voltage was generated during tests with a temperature gradient of 60 °C.

Black Silver: Three-Dimensional Ag Hybrid Plasmonic Nanostructures with Strong Photon Coupling for Scalable Photothermoelectric Power Generation.

The conversion of solar energy into electric power has been extensively studied, for example, by photovoltaics. However, photo-thermoelectric (P-TE) conversion as an effective solar-to-electricity conversion process is less studied. Here, we present an efficient full-solar-spectrum plasmonic absorber for scalable P-TE conversion based on a simple integration of light absorber and commercial thermoelectric modules. Our developed light absorber of silica-silver hybrid structures achieves an average absorption of 99.4% in the wavelength range from 200 to 2500 nm, which covers over 98% solar energy in this range. It thus appears fully matte black and is named black silver. The light absorber includes a hierarchical structure with Ag nanoparticles attached on three-dimensional SiO2 nanostructures, resulting in ultrahigh absorption. Strong localized surface plasmon resonance hybridization together with multiple scattering causes the perfect light absorption. Using the black silver as a light absorber for P-TE power generation, it can achieve a peak voltage density as high as 82.5 V m-2 under a solar intensity of 100 mW cm-2, which is large enough to power numerous electronic devices. By assembling 20 thermoelectric modules in series, we test their possibility of practical application, and they can also achieve an average voltage density of 70.66 V m-2. Our work opens up a promising technology that facilitates high-efficiency and scalable solar energy conversion via the P-TE effect.

Synergistic Optimization of the Thermoelectric and Mechanical Properties of Large-Size Homogeneous Bi0.5Sb1.5Te3 Bulk Samples via Carrier Engineering for Efficient Energy Harvesting.

Manufacturing an economically viable, efficient commercial thermoelectric (TE) module is essential for power generation and refrigeration. However, mediocre TE properties, lack of good mechanical stability of the material, and significant difficulties involved in the manufacturing of large-scale powder as well as bulk samples hinder the potential applications of the modules. Herein, an economically feasible single-step water atomization (WA) is employed to synthesize BST powder (2 kg) by Cu doping within a short time and consolidated into large-scale bulk samples (500 g) for the first time with a diameter of 50 mm and a thickness of about 40 mm using spark plasma sintering (SPS). The incorporation of Cu into BST greatly boosts the carrier concentration, leading to a significant increase in electrical conductivity, and inhibits the bipolar thermal conductivity by 73%. Synchronously, the lattice contribution (κL) is greatly reduced by the effective scattering of phonons by comprising fine-grain boundaries and point defects. Therefore, the peak ZT is shifted to the mid-temperature range and obtained a maximum of ∼1.31 at 425 K and a ZTave of 1.24 from 300 to 500 K for the BSTCu0.05 sample, which are considerably greater than those of the bare BST sample. Moreover, the maximum compressive mechanical strength of large-size samples manufactured by the WA-SPS process is measured as 102 MPa, which is significantly higher than commercial zone melting samples. The thermoelectric module assembled with WA-SPS-synthesized BSTCu0.05 and commercial n-type BTS material manifests an outstanding cooling performance (-19.4 °C), and a maximum output power of 6.91 W is generated at ΔT ∼ 200 K. These results prove that the BSTCux samples are eminently suitable for the fabrication of industrial thermoelectric modules.

Nanocomposites of GO/D‐Mannitol Assisted Thermoelectric Power Generator for Transient Waste Heat Recovery

Thermoelectric generators (TEGs) have received a great attention in the field of renewable energy resources due to their superior ability of converting untapped waste heat into usable electricity. In order to boost the conversion efficiency of TEG and to retrieve the transient heat, this paper demonstrates the role of nanostructured graphite (G) and graphene oxide (GO) decorated phase‐change material (PCM) of D‐mannitol attached with the hot end of commercial thermoelectric module on enhancement of conversion efficiency and power output. Presence of G and GO on the matric of D‐mannitol has been confirmed by powder XRD and FE‐SEM. The open circuit voltage (Voc) and short circuit current (Isc) of TEG attached with PDM, G/PDM, and GO/PDM were recorded for the heating and cooling cycles in the temperature range of 325‐450 K. Particularly, the experimentally measured Voc and Isc of TEG with only PDM are 1.23 V and 90 mA, respectively, for the temperature difference of ΔT ∽ 118 K, whereas the maximum Voc of TEG attached with GO/PDM drawn in presence of an external heater is 4.5 V for ΔT ∽ 118 K. Further, the maximum output power of TEG with GO‐PCM drawn in the heater‐ON and heater‐OFF is 1012.5 mW and 450 mW, respectively.

Development of a solid-state multi-stage thermoelectric cooler

In this work, a unique thermoelectric solid-state multi-stage cooler for operating temperatures up to ~140 K was developed. The extrusion technology was applied to fabricate thermoelectric legs with sufficient mechanical properties for the device construction. A cooling prototype was designed and fabricated using a four-stage commercial module and a two-stage ultra-low temperature module. The ultra-low temperature module, operating in the temperature range of 180–140 K, was fabricated using Bi0·91Sb0.09 alloys as an n-type leg and an optimized composition of Bi1·6Sb0·4Te3 as a p-type leg. The four-stage commercial thermoelectric module based on n- and p-type Bi2Te3 based alloys was utilized for operation in the temperature range of 180–300 K. The solid-state cooler was tested at a hot temperature Th = 300 K in a vacuum. At the cold temperature of the fourth stage 180 K, the maximum temperature difference of the ultra-low temperature module achieves high values of maximum temperature difference ΔT = 45 K and maximum cooling capacity Qc = 85 mW. Furthermore, we demonstrated the applicability of the ultra-low cooler for refrigeration up to 150 K for a mid-infrared sensor based on a PbTe photodiode with a cut-off wavelength λc ≈ 4.2 μm and a detectivity D ≈ 1010 cm Hz1/2/W revealing the potential of the developed device for practical applications.

Validation of commercial Bi2Te3-based thermoelectric generator modules for application as metrological reference samples

Traceability and the definition of uncertainty budgets are considered as necessary prerequisites for a meaningful characterization of thermoelectric generator modules (TEM). Due to the lag of standardized measurement techniques and characterization guidelines users and developers of measurement facilities cannot express uncertainty budgets on a normative base, but can only rely on own experiences and act according to best practise approaches. Reference samples are an appropriate method to investigate the accuracy of measurements and to provide insides into strengths and weaknesses of the employed characterization methods. Such references are still not available to date for measurements on TEM. In order to overcome this deficit this article discusses the applicability of commercially available Bi2Te3-based TEM to serve as metrological reference samples.Four TEM types from different manufacturers were investigated with regard to their stability, which was assessed on the base of the internal electric resistance Ri in the course of different experiments. The modules have been tested under constant temperature differences (ΔT = 150 °C / 175 °C) but variable mechanical pressure (2 MPa ≤ p ≤ 3.5 MPa). Further experiments have been conducted under constant pressure (p = 3 MPa) and variable temperature differences in order to determine the short-term stability. The long-term stability was assessed from thermal cycling experiments with observation times between 117 h and 443 h in dependence of the observed module stability. Significant differences could be observed regarding the stability of Ri, which ranged from very stable module types with maximum changes of ΔRi < 2.5% to modules with a relatively weak stability showing ΔRi > 13%. The sample-to-sample variation (homogeneity) of Ri was tested in a last step on five modules from two most stable types.

Experimental investigation of the performance of a thermoelectric generator at various operating conditions

Thermoelectric generators (TEG) is the device that can directly convert heat into electricity by the Seebeck effect, which is fascinated for waste heat recovery. An experiment was setup to study the influence of heat flux through the thermoelectric module on the power output and efficiency of a commercial Bi2Te3-based thermoelectric modules. The experimental result indicated that the power output evidently increased with the increasing heat flux through the thermoelectric module (TEM), while the conversion efficiency increased significantly at first then the tendency became mild with the increasing heat flux for a given air flow velocity and flow temperature. The temperature differences across the thermoelectric module are almost identical with various air velocity, while the power output and efficiency increased with the increase of cooling flow velocity with a fixed heat flux through the TEM. The power output and efficiency almost linearly decreased with the increase of cooling flow temperature with a fixed heat flux through the TEM and a fixed cooling flow velocity. The maximum output power can be obtained by maximization heat flux without exceeding the upper temperature limit of thermoelectric module.

Towards tellurium-free thermoelectric modules for power generation from low-grade heat

Thermoelectric technology converts heat into electricity directly and is a promising source of clean electricity. Commercial thermoelectric modules have relied on Bi2Te3-based compounds because of their unparalleled thermoelectric properties at temperatures associated with low-grade heat (<550 K). However, the scarcity of elemental Te greatly limits the applicability of such modules. Here we report the performance of thermoelectric modules assembled from Bi2Te3-substitute compounds, including p-type MgAgSb and n-type Mg3(Sb,Bi)2, by using a simple, versatile, and thus scalable processing routine. For a temperature difference of ~250 K, whereas a single-stage module displayed a conversion efficiency of ~6.5%, a module using segmented n-type legs displayed a record efficiency of ~7.0% that is comparable to the state-of-the-art Bi2Te3-based thermoelectric modules. Our work demonstrates the feasibility and scalability of high-performance thermoelectric modules based on sustainable elements for recovering low-grade heat.

Harvesting energy from sun, outer space, and soil

While solar power systems have offered a wide variety of electricity generation approaches including photovoltaics, solar thermal power systems, and solar thermoelectric generators, the ability to generate electricity at both the daytime and nighttime with no necessity of energy storage remains challenging. Here, we propose and verify an environment-friendly, sustainable, and cost-effective strategy of harvesting solar energy by solar heating during the daytime and harnessing the coldness of the outer space through radiative cooling to produce electricity at night using a commercial thermoelectric module. It enables electricity generation for 24 h a day. We experimentally demonstrate a peak power density of 37 mW/m^2 at night and a peak value of 723 mW/m^2 during the daytime. A theoretical model that accurately predicts the performance of the device is developed and validated. The feature of 24-h electricity generation shows great potential energy applications of off-grid and battery-free lighting and sensing.

Exhaust waste energy recovery using Otto-ATEG-Stirling engine combined cycle

In the present study, using the Stirling cycle and thermoelectric modules, the exhaust heat dissipation of a gasoline engine was recovered. In this regard, a gasoline engine, a Stirling engine, and a commercial thermoelectric module were first modeled and validated. In order to benefit from the Stirling engine along with the gasoline engine, it was necessary to redesign the Stirling engine heater to suit the needs of the project. The designed heater is a shell and tube heat exchanger, and on its shell, there are places to install thermoelectric modules. In Ansys CFX software, the performance of this heat exchanger was analyzed and its performance was evaluated. The results illustrated the maximum pressure drop is about 2.63 mbar. Also, the net power generated by the module set is in the range of 223–528 W, and the Stirling engine power for the temperature range of 358 °C − 535 °C was reported to be 1.8–6.8 kW. In total, the combined cycle power and efficiency increased by about 7% and 2.5% respectively. Finally, the analysis showed that fuel consumption has decreased by about 8% and about 0.7% of this amount was related to the performance of thermoelectric modules.

Cooling Microprocessors with Commercial Thermoelectric Module Powered by Pulsed Current

Cooling Microprocessors with Commercial Thermoelectric Module Powered by Pulsed Current

Proposing tube-bundle arrangement of tubular thermoelectric module as a novel air cooler

Usual commercial thermoelectric modules are produced in the form of flat shapes. However, tube-bundle arrangement of tubular thermoelectric modules as an air cooler (proposed for the first time in this paper as shown in the graphical abstract) is very meaningful and straightforward compared to the coolers made by flat-shape thermoelectric modules. It is assumed that, the water fluid moves through the inside of the tube-bundle thermoelectric (to adjust the hot surface temperature of the thermoelectric) while the air fluid moves through the outer surface of the tubular thermoelectric (cold side) in cross-section direction. In order to clarify the applicability of the tubular thermoelectric for aforementioned aim, thermal behavior of the tubular thermoelectric legs (in terms of temperature distribution through the legs, heat transfer rate and COP of the cooling process) are comprehensively studied in this paper via a validated 3D numerical simulation by consideration of appropriate boundary conditions. Moreover, geometric characteristics of tubular thermoelectric as an air cooler are investigated and presented in this study which have not been reported before. The results showed that tubular thermoelectric can be appropriately employed for said aim if thermal and geometric parameters are selected in desired range.