Lightweight wearable thermoelectric cooler with rationally designed flexible heatsink consisting of phase-change material/graphite/silicone elastomer

Heat transfer enhancement in latent heat thermal storage systems: Comparative study of different solutions and thermal contact investigation between the exchanger and the PCM

Thermal management systems (TMS) of armored ground vehicle designs are often incapable of sustained heat rejection during high tractive effort conditions and ambient conditions. Latent heat energy storage systems that utilize Phase Change Materials (PCMs) present an effective way of storing thermal energy and offer key advantages such as high-energy storage density, high heat of fusion values, and greater stability in temperature control. Military vehicles frequently undergo high-transient thermal loads and often do not provide adequate cooling for powertrain subsystems. This work outlines an approach to temporarily store excess heat generated by the transmission during high tractive effort situations through the use of a passive PCM retrofit thereby extending the operating time, reducing temperature transients, and limiting overheating. A numerical heat transfer model has been developed based on a conceptual vehicle transmission TMS. The model predicts the transmission fluid temperature response with and without a PCM retrofit. The developed model captures the physics of the phase change processes to predict the transient heat absorption and rejection processes. It will be used to evaluate the effectiveness of proposed candidate implementations and provide input for TMS evaluations. Parametric studies of the heat transfer model have been conducted to establish desirable structural morphologies and PCM thermophysical properties. Key parameters include surface structural characteristics, conduction enhancing material, surface area, and PCM properties such as melt temperature, heat of fusion, and thermal conductivity. To demonstrate proof-of-concept, a passive PCM enclosure has been designed to be integrated between a transmission bell housing and torque converter. This PCM-augmented module will temporarily strategically absorb and release heat from the system at a controlled rate. This allows surging fluid temperatures to be clamped below the maximum effective fluid temperature rating thereby increasing component life, reliability, and performance. This work outlines cooling system boundary conditions, mobility/thermal loads, model details, enclosure design characteristics, potential PCM candidates, design considerations, performance data, cooling system impacts, conclusions, and potential future work.

In this study, experimental investigation of phase change materials (PCM) integrated into building on ceilings was assessed for thermal management capabilities by comparing two building test models with and without PCM based on fluctuation in PCM temperatures owing to ambient temperature variations. Commercial organic PCM (OM-30) with a peak melting point of 31.10 C was used as PCM with high-density polyethylene (HDPE) as the encapsulation. Differential scanning calorimeter (DSC) was used to examine the thermophysical characteristics of PCM such as phase transition temperature, latent heat, and specific heat capacity. The various PCM temperature ranges included for the study are (i) Above phase change melting temperature range ii) within Phase Change melting temperature range iii) Proximity to PCM onset melting temperature range iv) proximity to PCM end melting temperature range. Under free-floating ambient Condition, the indoor air temperature was dropped in PCM installed room up to 1.69 °C, 5.79 °C, 2.26 °C, & − 2.87 °C compared to without PCM room for a PCM Melting temperature difference of 8.77 °C,1.55 °C, 1 °C & 0.44 °C respectively. Also, it was divulged that the PCM utilized 3.2%, 31.4%, 6.9%, & 12.27% of the total latent heat energy deployed in order to produce a temperature difference of 1.69 °C, 5.79 °C, 2.26 °C, & − 2.87 °C compared to without PCM room.

<title>ABSTRACT</title> <p>Thermal management systems (TMS) of armored ground vehicle designs are often incapable of sustained heat rejection during high tractive effort conditions and ambient conditions. The use of a latent heat energy storage system that utilizes Phase Change Materials (PCMs) is an effective way of storing thermal energy and offers key advantages such as high-energy storage density, high heat of fusion values, and greater stability in temperature control. Military vehicles frequently undergo high-transient thermal loads and often do not provide adequate cooling for powertrain subsystems. This work outlines an approach to temporarily store excess heat generated by the transmission during high tractive effort situations through use of a passive PCM retrofit thereby extending the operating time, reducing temperature transients, and limiting overheating. A numerical heat transfer model has been developed based around a conceptual vehicle transmission TMS. The model predicts the transmission fluid temperature response with and without a PCM retrofit. The developed model captures the physics of the phase change processes to predict the transient heat absorption and rejection processes. The model will be used to evaluate the effectiveness of proposed candidate implementations and provide input for TMS evaluations. Parametric studies of the heat transfer model have been conducted to establish desirable structural morphologies and PCM thermophysical properties. Key parameters include surface structural characteristics, conduction enhancing material, surface area, and PCM properties such as melt temperature, heat of fusion, thermal conductivity, etc. To demonstrate proof-of-concept, a passive PCM enclosure has been designed to be integrated between a transmission bell housing and torque converter. This PCM-augmented module will temporarily strategically absorb and release heat from the system at a controlled rate. This allows surging fluid temperatures to be clamped below the maximum effective fluid temperature rating thereby increasing component life, reliability, and performance. This work outlines cooling system boundary conditions, mobility/thermal loads, model details, enclosure design characteristics, potential PCM candidates, design considerations, performance data, cooling system impacts, conclusions, and potential future work.</p>

An overview of recent literature on the micro- and nano-encapsulation of metallic phase-change materials (PCMs) is presented in this review to facilitate an understanding of the basic knowledge, selection criteria, and classification of commonly used PCMs for thermal energy storage (TES). Metals and alloys with high thermal conductivity can be used as PCMs for rapid heat storage in compact systems owing to their high volumetric TES density. The emerging application of metal PCMs in different fields such as solar thermal energy management, smart wearable devices with thermal comfort control, and cooling of electronic devices call for the need of micro- and nano-TES particles, which can be synthesised in different forms to satisfy specific requirements. As metals are easily oxidised, especially at the micro- and nano-level, encapsulation of metal-based PCM particles is important for sustainable use at high operating temperature in ambient conditions. Recent studies focusing on the encapsulation of metallic PCMs at the micro- and nano-level have been reviewed and classified in terms of the melting point of metal/alloy PCMs used and types of encapsulation materials, such as oxides, polymers, carbon, and metals. The current review is expected to provide an outlook on novel metal and alloy PCMs with function-directed structures and superior TES properties for a broad range of applications.

Thermodynamic analysis of directionally influenced phase change material embedded building walls

Using PCM in buildings to reduce HVAC energy usage taking into account Saudi Arabia climate region

Novel solid–solid phase-change cascade systems for high-temperature thermal energy storage

Influence of PCM thermal conductivity and HTF velocity during solidification of PCM through the free cooling concept – A parametric study

Protein glycosylation can be vital for changing the function or physiochemical properties of a protein. Abnormal glycosylation can lead to protein malfunction, resulting in severe diseases. Therefore, it is important to develop techniques for characterization of such modifications in proteins at a sensitivity level comparable with state-of-the-art proteomics. Whereas techniques exist for characterization of high abundance glycoproteins, no single method is presently capable of providing information on both site occupancy and glycan structure on a single band excised from an electrophoretic gel. We present a new technique that allows characterization of low amounts of glycoproteins separated by gel electrophoresis. The method takes advantage of sequential specific and nonspecific enzymatic treatment followed by selective purification and characterization of the glycopeptides using graphite powder microcolumns in combination with mass spectrometry. The method is faster and more sensitive than previous approaches and is compatible with proteomic studies.

Comparative study of cooling performance for portable cold storage box using phase change medium

Observational study of modified solar still coupled with oil serpentine loop from cylindrical parabolic concentrator and phase changing material under basin

Potential of phase change materials and their effective use in solar thermal applications: A critical review

Thermoelectric cooling (TEC) systems offer solid-state, eco-friendly alternatives to conventional refrigeration but suffer from efficiency degradation due to hot-side heat accumulation. This study investigates the integration of phase change materials (PCMs) with thermoelectric modules to enhance cooling performance and thermal stability. A hybrid TEC-PCM system was designed, fabricated, and tested using three PCM types (paraffin wax, lauric acid, and stearic acid) under varying ambient conditions (25°C, 35°C, and 45°C). Experimental results demonstrate that stearic acid PCM achieved the highest coefficient of performance (COP) improvement of 24% and maintained cold-side temperatures 5.7°C lower than conventional TEC systems. Finite element analysis using ANSYS validated experimental observations with less than 3% deviation. The hot-side temperature rise was reduced by 12% with PCM integration, extending transient cooling duration by 200%. These findings establish PCM-enhanced thermoelectric systems as viable solutions for portable refrigeration, electronics cooling, and battery thermal management applications. Keywords: Thermoelectric cooling, Phase change material, Peltier effect, Thermal management, Coefficient of performance, Latent heat storage

The present work is to investigate the thermal conductivity of the phase change material (PCM) of stearic acid (SA) by using the supporting material of expanded graphite (EG). The EG is used with the mass ratio of 10%, 15% and 20%. SA is commercial grade and the EG is formed by thermal method using natural graphite powder and crystalline zinc nitrate. The composite materials of (SA/10% EG, SA/15% EG and SA/20% EG) are prepared by direct impregnation method. Thermal conductivity of pure SA and composite PCMs are investigated by laboratory apparatus of heat transfer base unit TD1002. The thermal conductivity of the SA/10%EG composite PCM has been improved to 0.64 W/mK from that of SA (0.28 W/mK) with the percentage enhancement of 129%. To verify the morphology of the materials, scanning electron microscopy (SEM) analysis is utilized. The results show that the EG is formed in multilayers with pores in which stearic acid is well absorbed. The charging characteristics of pure SA, SA/10% EG and SA/15% EG for low temperature latent heat storage (LHS) system are studied experimentally. The system is applied for domestic water heating. The PCM is filled in a 33 mm diameter cylindrical copper tube and placed in hot water storage tank. The water is filled in tank from the top section through the distributor to uniform entry. The phase change phenomena of the PCMs are measured by inserting thermocouples at two layers of PCM tube. The result shows that the melting time decreases with the increasing mass ratio of expanded graphite in composite PCM. Although the melting time of both layers are nearly the same at the experiment of composite PCMs, the lower layer takes longer time than upper layer for pure PCM. The charging time is decreased by 67% for SA/10%EG and 79% for SA/15% EG composite PCM from that value of pure SA.