Thermoelectric Refrigeration Research Articles

Simulation analysis and optimization of thermoelectric refrigeration and air conditioning

Abstract Thermoelectric refrigeration technology is mainly through the Peltier effect to achieve refrigeration, thermoelectric refrigeration air conditioning needs to be combined with a certain air flow rate to realize the separation of cold and heat, and make full use of the cold end to realize the refrigeration function, or else the refrigeration efficiency is seriously affected. Based on the ICEPAK simulation platform of ANSYS, we analyze the influence of structure and parameter settings on the conversion efficiency of thermoelectric refrigeration air conditioning fan under the established boundary conditions, establish the relationship between air flow rate and temperature drop value, and put forward the optimization of the product structure design scheme, and the results of the optimization scheme show that there is a peak in the operating current at a certain heat dissipation efficiency; and lengthening the length of the air ducts through the optimization of the structure can enhance the refrigeration effect of the air conditioner.

Optimizing COP by RSM and MATLAB model of mini refrigerator based on thermoelectric units driven by solar photovoltaic

AbstractEnergy scarcity in the world and the pollutants resulting from excessive use of conventional energy aroused the need for sustainable alternatives that are environment friendly. A multi-use thermoelectric refrigerator powered by solar energy to obtain the lowest consumption with the highest efficiency. The designed refrigerator is based on the Peltier effect using Peltier units where a temperature difference is created between the junctions by applying a voltage difference across the junction. This study investigates the performance of a refrigerator cooling system powered by a photovoltaic (PV) system. The research aims to assess the efficiency, effectiveness, and feasibility of utilizing solar energy to drive refrigeration, particularly in off-grid or environmentally conscious applications. Through a comprehensive experimental setup and data analysis, the study examines energy consumption, cooling efficiency, and overall system performance under varying conditions. The findings contribute valuable insights into the potential of PV-powered refrigerators as sustainable cooling solutions. It relies on a control unit that measures the resulting temperature to determine the appropriate connection mode to give the highest cooling efficiency. The average solar radiation when operating for 8 h, for the different seasons of the year was 149.5, 67.5, 119.3, and 118.3 w/m2 in summer, winter, spring, and fall, respectively. The average cooling energy consumption was 107.25, 137.04, 107, and 138.08 w for temperatures (20 ± 1, 15 ± 1, 20 ± 2, and 15 ± 2) °C respectively that proof solar radiation is sufficient to produce energy for the summer of cooling temperatures up to 15 °C, while in the spring and fall it is sufficient to 20 °C. The Fast not Eco mode is the least energy consuming and the fastest cooling, it can be used for rapid cooling at a short time less than an hour. The best mode in the case of continuous operation is the case of as next Eco mode cooling temperature of 20 ± 0.1 °C. The MATLAB Simulink model was developed to reduce the design cycle and facilitate the integration of solar photovoltaic with the TEC. The optimal operating point is identified through simulation and validated through experimental analysis, the optimal COP was 71.089% by Response surface methodology (RSM).

Hydrogel‐Based Functional Materials for Thermoelectric Applications: Progress and Perspectives

AbstractHydrogels are renowned for their complex structures and unique physicochemical properties, establishing them as key materials in bioenergy harvesting applications. They are used in various applications, including triboelectric nanogenerators, piezoelectric, hydraulic, thermoelectric, and biofuel cells. Among these, hydrogels as key materials for thermoelectric applications represent a technology capable of continuously converting biological energy (thermal energy) into electrical energy. This technology shows great potential and commercial value in body monitoring, energy storage, and human‐machine interaction applications. Given its rapid development, a timely review focusing on the research progress of hydrogels and their composites in thermoelectric technology is presented. This review discusses various types of hydrogels used for thermoelectric power generation and refrigeration, their unique properties, strategies for enhancing their thermoelectric performance, and their applications in the field. Finally, the remaining challenges and feasible strategies are identified for improving the efficiency, stability, application range, and system‐level integration of next‐generation hydrogels for thermoelectric applications.

Advancing sustainable cooling: Performance analysis of a solar-driven thermoelectric refrigeration system for eco-friendly solutions

The solar-powered thermoelectric refrigerator (SPTR) is an innovative approach that uses solar energy to cool spaces. Its effectiveness relies on solar insolation rates and an intelligent dual-axis solar tracking system (STS) that maximizes solar energy capture. Performance analysis of SPTR with the fixed panel solar system (WST) and dual-axis STS by keeping the SPTR at a standard ambient temperature of 25 °C was carried out under local climate conditions. The experimental test setup includes a thermoelectric refrigerator (TER), thermoelectric module (TEM), solar panels, and STS. The experimental findings showed that the coefficient of performance (COP) of SPTR depends on the solar irradiance, the system's input power, the surface temperature of the solar panels, and the cooling rate. The maximum and minimum values of COPs were 1.19 and 0.27 for directly coupled SPTR with a WST and 2.07 and 0.39 for STS, respectively. Compared with the stand-still solar system, a COP enhancement of 44–75 % is achieved. The results also show that the cooling load is a function of the refrigerated space, and the products are to be cooled, which is affected by the thermoelectric properties of the TEM. The cooling rate is recorded at its maximum when the system is operated using an STS on a clear sunny day with a maximum solar insolation rate. The SPTR has proven to be environmentally friendly, the best alternative to conventional cooling systems, and sustainable due to the independence of traditional energy resources.

Efficient portable thermoelectric refrigerator developed with a temperature control system mode at best COP for different seasons and conditions of the year

ABSTRACT Global energy scarcity and pollution resulting from excessive energy consumption are among the most important causes of global warming, in addition to using Freon, which poses a danger to the environment. This led to searching for sustainable alternatives that use less energy to alleviate environmental difficulties and are eco-friendly. The portable thermoelectric refrigerator was developed to control the temperature required in different seasons of the year, for those who live in rural areas in Egypt (such as deserts). The main control unit has five modes (Economic, Minimum, Medium, Fast and Fast not Economic) based on the best coefficient of performance (COP) and minimum energy. The results showed the highest COP, for the economic mode with an 8°C difference in temperature, and the lowest COP with a 26.4°C difference in temperature for the fast not economic mode. On the other hand, the difference temperatures of 12.5°C,18.2°C and 23°C of the mode minimum, medium and, fast, respectively.

Design and Fabrication of a Mini Refrigerator Using a Peltier Thermoelectric Module

A mini thermoelectric Peltier Refrigerator was designed and built in this study. The Peltier thermoelectric cell was attached in between an external heat sink and internal radiator that acted to remove heat from the internal space of refrigeration box to be conducted and removed to the ambient. To ensure the success of this study several criterions are to be satisfied such as portability, size and cost of the system. The design of the system is based on the principles of thermoelectric module (i.e. Peltier effect) to create a hot side and a cold side. Thermoelectric refrigeration work on the principle of see beck effect in which the voltage is applied between two different combinations of metal and due to effect of see beck the cooling and heating phenomena happens which can be used accordingly for different purposes. The cold side of the thermoelectric module is used for refrigeration purposes; provide cooling to the vaccine chamber. On the other hand, the heat from the hot side of the module is rejected to the surroundings with the help of a heat sink and fan assembly.

Performance optimization of thermoelectric and vapor compression hybrid refrigeration system by allocating power

To enhance the refrigeration efficiency of the thermoelectric and vapor compression hybrid refrigeration system and optimize the allocation of power during system operation, a dimensionless parameter, the power allocation ratio coefficient (θ), is proposed. It represents the ratio of the input power of the thermoelectric refrigeration system to the total input power. A mathematical model of the hybrid refrigeration system is established to investigate the impact of θ on the cooling temperature (Tc), cooling capacity (Qc), and coefficient of performance (COP) of the system. An experimental platform is constructed to validate the mathematical model and explore the relationship between the optimal θ and system operating parameters. The findings demonstrate that, under a constant total input power, as the θ increases, the cooling temperature initially decreases and then increases, whereas the Qc and COP first increase and then decrease. There exists an optimal power allocation relationship for the two-stage refrigeration system, which maximizes the refrigeration performance of the hybrid refrigeration system. When the total input power is 100 W, the optimum θ is 0.52, resulting in a cooling temperature of −55.23 °C and a COP of 0.13. As the total input power increases, the optimal θ decreases. The cooling temperature rises, the optimal θ increases. The ambient temperature increases, the optimal θ also increases. An optimized relationship equation is obtained by fitting the calculated results of the operating parameters and the optimal θ, providing a theoretical basis for the control of power allocation in practical operation of the two-stage refrigeration system within the hybrid refrigeration system.

EXPERIMENTAL AND NUMERICAL STUDY ON EFFECTS OF NEW-GENERATION FINNED HEAT EXCHANGER ON THERMAL PERFORMANCE OF THERMOELECTRIC COOLING SYSTEMS

In this study, an attempt has been made to increase the efficiency of the thermoelectric refrigerator by designinig a new-generation finned heat exchanger. Surface extension, which is one of the most applied passive heat transfer enhancement techniques, was applied for this finned heat exchanger. In this application, the heat absorbed from the cooling room is transferred to the external environment more effectively. In addition, by using an external thermoelectric element (which is installed with the secondary heat exchanger), the heat exchanger cools down faster and the heat is transferred to the environment more quickly. The manufactured cooling system was tested experimentally under different working conditions, including natural and forced convection. The effects of air velocity and applied voltage to the external TE module on thermal performance were examined. Additionally, the external finned heat exchanger has been simulated and heat transfer characteristics have been evaluated using computational fluid dynamics. The lowest and highest COP values have been obtained as 0.003 and 0.011, respectively, when the external TE module has been passive. By providing 12 V for the external TE module, the lowest and highest COP values have been observed as 0.0031 and 0.0042, respectively. In addition, the importance of surface extension applications for the efficient operation of thermoelectric elements has been emphasized.

Giant longitudinal and transverse magnetothermoelectric effects in a van del Waals semimetal TaCo2Te2

TaCo2Te2 exhibits giant longitudinal and transverse magneto-thermoelectric effects, suggesting its great potential for thermoelectric refrigeration applications.

Solar-powered thermoelectric refrigeration with integrated phase change material: An experimental approach to food storage

In this paper, a novel phase change material (PCM) based Thermoelectric (TE) food storage refrigerator incorporating an integrated solar-powered energy source is introduced. The novelty aspects of this research lie in the unique combination of PCM with solar energy, not only to maintain temperatures below 5 °C, vital for reducing food spoilage, but also in designing extra experiments using water as a cooling method to enhance system performance. Designed to preserve a diverse range of fruits and vegetables with different moisture content below 5 °C, the system innovatively employs PCM to extend cooling time, reduce energy load, and avoid conventional refrigerants, contributing to environmental sustainability. Experimentally, the average time for PCM solidification was around 3.5 h, with a corresponding latent heat release time, maintaining a temperature range of 0 to 5 °C. The system effectively accommodated various food items with water content levels from 50 % to 99 %, achieving the target temperature within around 2 to 4 h and demonstrating a promising coefficient of performance (COP) of 0.69. A standout innovation included the utilization of water flow through copper piping to accelerate heat removal from TEC, enhancing the performance of the system and reducing the solidification time of PCM by approximately an hour. This research represents a significant advancement in refrigeration technology, highlighting the feasibility and optimization potential of integrating solar energy and PCM, and introduces a new direction for enhancing efficiency through water-cooled heat sinks.

Thermal analysis of thermoelectric active cooling including external thermal resistances

Thermoelectric active cooling uses nontraditional thermoelectric materials with high thermal conductivity, high thermoelectric power factor, and relatively low figure of merit (ZT) to transfer large heat flows from a hot object to a cold heat sink. However, prior studies have not considered the influence of external thermal resistances associated with the heat sinks or contacts, making it difficult to design active cooling thermal systems or compare the use of low-ZT and high-ZT materials. Here, we perform a non-dimensionalized analysis of thermoelectric active cooling under forced heat flow boundary conditions, including arbitrary external thermal resistances. We identify the optimal electrical currents to minimize the heat source temperature and find the crossover heat flows at which low-ZT active cooling leads to lower source temperatures than high-ZT and even ZT→+∞ thermoelectric refrigeration. These optimal parameters are insensitive to the thermal resistance between the heat source and thermoelectric materials, but depend strongly on the heat sink thermal resistance. Finally, we map the boundaries where active cooling yields lower source temperatures than thermoelectric refrigeration. For currently considered active cooling materials, active cooling with ZT < 0.1 is advantageous compared to ZT→+∞ refrigeration for dimensionless heat sink thermal conductances larger than 15 and dimensionless source powers between 1 and 100. Thus, our results motivate further investigation of system-level thermoelectric active cooling for applications in electronics thermal management.

Numerical investigation of a battery thermal management system integrated with vapor chamber and thermoelectric refrigeration

An efficient battery thermal management system is crucial for ensuring the working temperature environment of batteries and extending their lifespan. In this paper, a novel battery thermal management system combining vapor chambers and thermoelectric coolers is proposed to improve the battery's thermal behavior. Also, a complete fluid-thermal-electric multiphysics numerical model for the proposed system is built to predict its thermal performance under different cooling parameters. Results show that the use of thermoelectric coolers and vapor chambers can greatly lower the maximum temperature and temperature difference of batteries. Although the maximum temperature decreases with the increase of air convection heat transfer coefficient and coolant flow rate, the temperature difference increases at the same time. Under the given optimal air and water cooling parameters, it is noticed that as the input current of thermoelectric coolers increases, the maximum temperature and temperature difference show a pattern of decreasing first and then increasing. The optimal air convective heat transfer coefficient, coolant flow rate, and input current of 50 W/(m2·K), 0.04 m/s, and 1.5 A, respectively, are suggested, which corresponds to the maximum temperature of 39.83°C and temperature difference of 5.97°C. The present research introduces a fresh perspective on efficient battery thermal management, offering detailed insights into the utilization of thermoelectric cooling for this purpose.

An approach to improve the efficiency of cooling enhancement of a thermoelectric refrigerator through the use of phase‐change materials

AbstractIn this study, a technique is suggested to enhance the temperature difference for cooling and energy efficiency of thermoelectric cooler (TEC) used in cooled detectors when subjected to high current conditions. Embedding a structure for storing heat during phase change is the basis of this method at the heat sink. A simulation model was created for a common two‐stage series TEC with an asymmetrical design, which is coupled with a structure for storing heat through phase change. The research examined how phase transition heat storage impacts the coefficient of performance (COP) and refrigeration temperature difference across various phase‐change substances, heat transfer coefficients at the hot end, currents, and the height of the phase‐change material (PCM). The findings suggest that the suggested approach of combining PCM with TEC can efficiently lower the cold end temperature of TEC by a maximum of 20 K, enhance the temperature gap by a maximum of 16 K, and preserve the consistency of the optimized quantity across various hot end heat transfer coefficients. During the phase‐change process of PCMs, the COP of TECs integrated with PCM is found to increase by an average of 2%–3% compared to TECs without PCM integration. Under the maximum current operating condition, the cryogenic temperature can be optimized to a minimum of 238 K. In summary, the proposed method of integrating phase‐change heat storage with TECs provides a promising solution for improving their cooling performance and energy efficiency in cooled detectors under high current conditions. Additional investigation can be conducted to explore the practical application of this approach and enhance the design parameters for various uses.

Effect of lattice defects on electronic structure and thermoelectric properties of two- dimensional WS2 materials

WS2 is a kind of thermoelectric material with great development potential that is used for thermoelectric power generation and refrigeration. In this study, the NEGF-DFT method was used to study the thermoelectric properties of intrinsic 2D-WS2 and the effects of periodic vacancy or substitution atoms on their electronic structure and thermoelectric properties. The results show that the ZT value of p-type 2D-WS2 is better than that of n-type 2D-WS2. The thermoelectric properties of p-type 2D-WS2 and p-type 2D-WS2 with O-atom replacing S-atom are better than those of the corresponding n-type 2D-WS2, while the thermoelectric properties of n-type 2D-WS2 with periodic defects and n-type 2D-WS2 with Se-atom or Te-atom replacement for S-atom are better than those of the corresponding p-type 2D-WS2. The ZT values of n-type 2D-WS2 with periodic defects, n-type 2D-WS2 with Se-atom replacement for S-atom, and n-type 2D-WS2 with Te-atom replacement for S-atom are 2.973, 3.383, and 3.0413, respectively, which indicates 2D-WS2 with Se-atom replacement for S-atom has the best thermoelectric performance.

Efficient Separation and Purification Method for Recovering Valuable Elements from Bismuth Telluride Refrigeration Chip Waste.

Bismuth telluride and its alloys are widely utilized in thermoelectric refrigeration and power generation devices. Waste bismuth telluride-based cooling chips contain valuable elements; however, recycling processes for these materials remain underdeveloped due to their complexity. In this study, we developed a concise and efficient chemical method that does not require expensive reagents or equipment, enabling the separation and purification of tellurium, bismuth, selenium, and antimony from waste bismuth telluride-based cooling chips. Initially, the waste was leached with HCl and NaClO3 to dissolve primary elements and recover 99.9% of selenium using hydroxylamine hydrochloride. Subsequently, Na2S and NaOH were employed for precipitation and leaching, resulting in a solution containing tellurium. The precipitated residue was treated with HNO3 to oxidize antimony into insoluble SbOHN and dissolve bismuth completely. 99.8% of the bismuth telluride waste was dissolved via oxidative leaching through hydrolysis. A small amount of sodium sulfide reduced the precipitation percentage of tellurium from 11.9% to 7.5% in an alkaline solution, and the direct recovery percentage of tellurium in the form of TeO2 exceeded 90%, while the purity of TeO2 reached 99.9%. By adjusting the pH of the bismuth solution to 0.15, 98.9% of the bismuth was able to precipitate and be recovered as BiOCl, with the purity also reaching 99.9%. In summary, this study presents an efficient hydrometallurgical method for treating bismuth telluride waste and provides theoretical guidance for reagent dosage, demonstrating the significant potential for industrial applications.

Inverse current induced thermoelectric conversion in a parallel-coupled double quantum dot system

We investigate the thermoelectric transport and conversion of a parallel-coupled double quantum dot system, which consisting of two capacitively coupled quantum dots in the Coulomb-blockade regime. We found that the system exhibits an unconventional thermoelectric conversion process induced by the inverse current effect, which is attributed to the increased Coulombic interaction between quantum dots, resulting in strong asymmetry in the system. We study the transport properties of steady-state particle current and heat current, and analyze the influence of Coulomb interaction on the thermodynamic characteristics of unconventional thermoelectric heat engines and refrigerators.

Design and Fabrication of Solar-Powered Portable Thermoelectric Refrigeration System for Thermolabile Pharmaceuticals

Abstract: In order to maintain the therapeutic efficacy of thermolabile medicine and vaccines, electrical energy must be continuously supplied. For remote areas lacking access to electrical electricity, this poses a serious dilemma. The potency level of thermolabile medications and vaccines is decreased, particularly during last-mile delivery, which causes significant financial loss. In this study, we designed and developed a portable active refrigeration system that runs on solar photovoltaic cells for the refrigeration of thermolabile pharmaceuticals to be utilized in rural areas without access to electricity, especially to facilitate last-mile vaccination delivery. The system makes use of a thermoelectric refrigeration system that, when given electrical power, causes a temperature difference based on the Peltier effect. It will be demonstrated that a solar panel with a peak power of roughly 50W and batteries with a storage capacity of 10Ah are needed for a typical application for vaccine refrigeration. The developed refrigeration system has a 3-liter volume capacity and can store 150 vaccine ampules, each with a 10ml capacity, at temperatures between 2°C to 8°C using a Peltier cell (TEC), that consumes 66 W at 12V

Photovoltaic thermoelectric cooling system for off-grid vaccine refrigerator: an experimental study

The rapidly rising demand for refrigeration technologies, mainly in refrigeration and air conditioning, medical applications, and electronic component cooling, produced much more energy than required. Thermoelectric refrigeration is an innovative way to use additional energy to cool and reserve cooling. In this research, a photovoltaic-thermoelectric refrigeration system capable of sustaining vaccine storage within the limit of 2–8 °C has been established by experimentally optimizing its volume and performance. The design specification is to cool the volume using forced convection to the desired temperature range in less than 30 min and sustain retained heat for at least the next hour. The experimental research is divided into two stages: the first determines the optimal volume of vaccine storage under different testing conditions using only grid power, and the second analyses storage performance using solar energy through photo voltaic (PV) integration. The solar direct drive and the solar drive with battery support have been timed, revealing a holding period of 4 h, 46 min and 5 h, 29 min, respectively. The refrigerator's design criteria, prospective characteristics, and final design are all thoroughly highlighted. Finally, we conclude that this research will likely benefit the modeling and analysis of thermoelectric cooling systems.

Experimental investigation and analysis of cooling performance of solar thermoelectric refrigerator

Nowadays, a potential alternate source of renewable energy for heating and cooling purposes is solar thermal energy. In remote areas electricity problems, the solar cooling and heating are very useful for living. The present research is focus to develop a solar thermoelectric refrigerator (STER) by using thermoelectric module based on principles of Peltier effect (creating cold and hot zone). Inside the refrigerator compartment, the cold side zone of the thermoelectric module is used for refrigeration. However, the rejected heat from other hot side of module to ambient surrounding through heat sinks and fans. The experimental model considers a steel aluminium box of dimension 200 × 195 × 300 mm3 having two thermoelectric (TE) modules and two heat sink with cooling fan to investigate the performance evaluation of solar thermoelectric refrigerator. The STER unit utilises a 100 W solar panel. The experimental result of double module with internal fan shows that the STER unit reduces room temperature of 33 °C to 4.1 °C in 44 min with coefficient of performance (COP) of 0.61. Therefore, the present novel refrigeration system is augmented for domestic and medicine storage purpose in remote area with economically viable and environmental friendly.

Experimental investigation and life cycle assessment of a phase change material (PCM) based thermoelectric (TE) refrigerator

Experimental investigation and life cycle assessment of a phase change material (PCM) based thermoelectric (TE) refrigerator