Heat Storage Capability Research Articles

Emergence of rectangular shell shape in thermal energy storage applications: Fitting melted phase changing material in a fixed space

Here we document the effect of heat transfer fluid (HTF) tube position and shell shape on the melting time and sensible energy requirement for melting a phase change material (PCM) in a multitube latent heat thermal energy storage (LHTES) application. Tube location and shell shape are essential as the shape of the melted region, i.e. similar to the boundary layer, affects convective heat transfer performance. HTF tube total area is fixed in all cases to have the same amount of PCM. In order to eliminate the effect of heat transfer surface area variation, results of two- and four-tube configurations were compared within themselves. Liquid fraction, sensible enthalpy content, and latent/sensible enthalpy ratio relative to time were documented for two and four HTF configurations in various shell shape and tube locations. Results show that eccentric two tubes with rectangular shell decreases melting time and sensible energy requirement from 67 min to 32 min and from 161.8 kJ/kg to 136.3 kJ/kg for 72.3% liquid fraction, respectively, in comparison to the concentric tubes with the circular shell. When the number of HTF tubes increases to four, then the required melting time and sensible energy decrease 80% and 3.8%, respectively, for PCM to melt completely as the concentric tubes and circular shell is replaced with eccentric tubes and rectangular shell. Results of liquid fraction variation relative to time show that S-curve of melting becomes steeper if PCM distribution is such that the intersection of melted regions is delayed. Therefore, melted PCM regions could be packed into a shell that minimizes melting time and required sensible energy. Even rectangular shell shape increases the heat transfer surface (increased heat loss rate) because melting time has decreased greatly, total energy lost to the ambient from the surfaces of shell decreases. Eccentricity slows down the solidification process but due to increased heat loss rate from the surface, rectangular shell enables faster solidification than circular shell shape. There is a trade off in between solidification time and heat loss energy for rectangular channels which can be optimized by selecting proper insulation thickness. Overall, the results show that without any thermal conductivity enhancement (TCE) method, melting performance and latent heat storage capability can be significantly enhanced as decreasing the sensible heat storage by fitting the melted PCM regions into a fixed space for the applications where charging speed is lot faster than discharging.

Biphasic organohydrogels based on phase change materials with excellent thermostability for thermal management applications

Abstract Innovative thermal management materials are in high demand for construction of energy-efficient systems. Evaporative cooling hydrogel has been extensively investigated in passive building cooling owing to its cost-effective and environmental-friendly characteristics. However, poor mechanical properties and shape instability severely restrict its scope and lifespan. In this study, we report an ingenious and effective thermal management material, the PCMs organohydrogel, with advanced thermal performance and outstanding shape and thermal stability, which integrates the advantages of evaporative cooling performance of water and latent heat storage capability of eicosane. The biphasic PCMs organohydrogel was synthesized by the CAA-HRP-H2O2 ternary enzyme-mediated polymerization of the eicosane-in-water emulsion stabilized by the cellulose acetoacetate (CAA). CAA played important roles in the system not only as the emulsifier but also as the polymerization mediator. The encapsulation of PCMs by the organohydrogel provides the composites outstanding thermal stability as the decomposition temperature of the eicosane was elevated by 101 °C. Furthermore, the PCMs organohydrogel exhibits excellent thermomechanical performance and shape memory effect because of the wrapped phase-transition micro-inclusions and the interfacial tension of heterophases. The application of the PCMs organohydrogel as passive cooling material on the model house roof was demonstrated. The cooling effectiveness of the PCMs organohydrogel was investigated, indicating that the biphasic PCMs organohydrogel is expected to be an efficient and reliable passive thermal management material in building thermoregulations.

Performance investigation of a passive battery thermal management system applied with phase change material

Lithium-ion batteries will produce a lot of heat during working, which can increase the temperature and temperature difference in the battery module, and seriously impair the capacity, life, and safety of the batteries. Therefore, an effective thermal management system should be implemented to control the temperature of the batteries, while reducing the energy consumption and cost of the system as much as possible. In this paper, a passive, low-cost battery thermal management system consisting of pouch lithium-ion cells and phase change material units is designed. Based on the heat production process of the battery and heat transfer theory of the phase change material, a numerical model is built and the performance of the thermal management system is analyzed. It is found that the phase change material units can effectively decrease the maximum temperature and the maximum temperature difference on the cell at the end of discharge, and thus have good heat storage capability and temperature equalization capability. After insulating heat dissipation from the surfaces of the phase change material units, a temperature retaining function can also be achieved. The effects of the design parameters of the phase change material unit on its thermal management performance are further investigated, including the thermal conductivity, viscosity, and latent heat of the phase change material, the thickness of the phase change material unit, and the thermal conductivity of the unit shell. It could provide theoretical references and technical means for the design and implementation of passive, low-cost battery thermal management systems applied with phase change materials.

Investigation on The Thermal Performance of Evacuated Glass-Thermal Absorber Tube Collector (EGATC) for Air Heating Application

Existing design of Heat-Pipe Evacuated Tube Collector (HP ETC) for solar water heating require storage tank and additional heat exchanger required for air heating application which leads to the extra spacing and costing requirement. HP ETC have better thermal performance to produce high outlet temperature than flat plate collector (FPC), especially during diffuse solar radiation. But HP ETC normally focusing on water heating system. Furthermore, HP ETC and FPC installation need to be positioned either to south or north facing to ensure the solar thermal collector absorbs more solar radiation. Meanwhile, HP ETC need to be tilt at the correct angle to maximize the performance of the system. These could lead to design limitation. The aim of this research is to develop the new design of Evacuated Glass-Thermal Absorber Tube Collector namely EGATC for drying application. It was developed from conventional HP ETC evacuated glass tube. In this study comparison result of EGATC and HP ETC performance were evaluated. The three days outdoor experiment proves that the performance of EGATC was better than HP ETC in air heating application which is provide higher outlet temperature. Based on the result, EGATC (Day 1: 50.9 oC, Day 2: 53.9 oC, Day 3: 49.2 oC) performed better with slightly higher temperature at outlet temperature compare with HP ETC (Day 1: 46.7 oC, Day 2: 50.3 oC, Day 3: 46.9 oC). It is concluded that EGATC have better performance in term of temperature different and outlet temperature as compared to HP ETC. EGATC (Day 1: 53.6%, Day 2: 50.6%, Day 3: 49.8%) also have greater efficiency in term of heat storage capability as compared to HP ETC (Day 1: 42.7%, Day 2: 41.6%, Day 3: 41.1%). Regarding energy buffer storage, EGATC have better energy storage compared to HP ETC at sudden weather change such as diffuse solar radiation during clouds. The outlet temperature of EGATC (42.3 oC) was remained slightly higher compared to HP ETC (39.9 oC) at the beginning. The outlet temperature gradually drops slower during discharging period until the end of the experiment for 15 minutes towards outlet temperature 41.1ºC and 37.2ºC for both EGATC and HP ETC with temperature difference 1.2ºC and 2.7ºC respectively.

Increasing the transmission performance of a conventional 110 kV cable line by combining a hydronic concrete pavement system with photovoltaic floor tiles

By combining the photovoltaic (PV) effect, heat exchanger principle, heat storage capability and phenomena of heat generation in PV cells and power cables, it is possible to increase significantly the transmission performance (i.e. the ampacity) of any 110 kV underground cable line. This can be achieved by installing power cables in a trench which is completely filled with high thermal conductivity bedding and which is covered with a hydronic concrete pavement (HCP) and a layer of PV floor tiles. This HCP, a heat storage system and a circulating pump are the three main parts of a HCP system, which should be used as a cooler for the PV tiles and cables. In particular, the PV cells would generate waste heat and direct current electricity from sunlight (using the PV effect), the cable bedding would conduct waste heat well from the cables to the heat collecting pipes of the HCP system (by improved heat conduction), while the HCP system would collect and store waste heat from the PV cells and cables as well as some heat from the Sun (using the heat exchanger principle and heat storage capability). The main aims of this paper are to show that the proposed method is highly energy-efficient, cost-effective and applicable in practice. The proposed method is regarded as a novelty, while the electricity generation in the PV floor tiles and the storage of heat within the HCP system represent additional advantages of this method. An adequate experimental background, one reference FEM-based model and one necessary base case are provided. For specified environmental conditions, the proposed method is verified numerically by means of COMSOL Multiphysics. Finally, the results of a techno-economic analysis are presented and discussed.

Experimental and computational study of phase change material based shell and tube heat exchanger for energy storage

The storage of thermal energy is an important issue that needs to be addressed. The wastage of heat energy, such as in an automobile or thermal power plant exhausts, means the loss of useful heat energy that could have been reused considering the present energy crisis scenario. The Phase Change Material (PCM) plays one such role in harnessing, storing, and reusing the waste heat energy. These materials have a unique property of changing their phase from solid to liquid whenever some heat energy is provided to them. It utilizes a latent heat storage method at a fairly constant temperature. In the present study, the shell and tube heat exchanger (HE) with thermal energy storage containing PCM (a mixture of organics) is tested for its heat storage capability. This PCM changes its phase at approximately 58 °C to 65 °C, and its operating range is 60 °C to 70 °C. The Performance of heat exchanger is investigated for a single round of temperatures for both charging and discharging cycles. The simulation has carried out to study the melting characteristics of PCM using ANSYS fluent. During the charging cycle, the heat energy stored in the PCM is 458.23 kJ for a duration of 100 min whereas, heat given by PCM material to the water during discharging cycle is 316.008 kJ for a duration of 50 min. It can be concluded that heat energy which is stored in the HE can be extracted effectively and used for suitable applications which operate at reasonably high temperatures.

State of the Art of Phase Change Material (PCM) for the Purpose of Heat Storage and Transfer in Cylindrical and Rectangular/Square Shells/Tubes – A Review

The state of the art of the PCM’s reveals enabled characteristics that opens the door for multiple heat transfer and storage phenomena. The PCM absorbs, stores, and releases the energy during its phase change thus it most widely helps in latent heat transfer techniques. Nowadays Nano-fluid and Nano-phase change materials are replacing the general phase change materials because of its high heat transfer and storage capability. Further, varieties of passive heat transfer techniques such as heat exchangers of shell/tube type of various patterns and geometries are utilized to optimize the thermal energy. The artificial neural network is embedded in the system to recognize the pattern for faster processing. In this article, the PCM heat storage and transfer techniques are critically reviewed in comparison with the Cylindrical and Rectangular/Square shells/tubes based on the effect of parameters such as solidification/melting performance, enthalpy, fluid flow pattern in the liquid molten state, types of PCM used, etc. The numerical/analytical and experimentation techniques are categorized based on the results of various researcher and conclusion is established.

Thermophysical Properties of Metal-Insulator Transition Materials During Phase Transition for Thermal Control Devices

This study reports on the fabrication of metal-insulator transition materials and measurement of the temperature dependency of their thermophysical properties, namely, specific heat, thermal conductivity, and total hemispherical emittance to evaluate the potential of these materials as multifunctional thermal control devices. Perovskite-type manganese oxide, La0.8Sr0.2MnO3 (LSMO) and La0.8Pb0.2MnO3 (LPMO), and vanadium dioxide (VO2) are selected as candidate materials. LSMO and LPMO are prepared using the solution combustion and simple sintering methods, and VO2 is prepared using the spark plasma sintering method. The phase transition temperatures, specific heat capacities, and heat storage capabilities during the phase transition of these materials are measured via differential scanning calorimetry. The thermal conductivities are measured via AC calorimetric method. The total hemispherical emittances are measured using the steady-state calorimetric method. Results show that VO2 has the highest heat storage capability during phase transition. The large change in the total hemispherical emittances of LSMO and LPMO and the large change in the thermal conductivity of VO2 before and after phase transition are confirmed. Moreover, tungsten-doped vanadium dioxide (VWO2) is fabricated to reduce the phase transition temperature to much lower than that of VO2, and the measurement results of its thermophysical properties are also presented.

Crafting visible-light-absorbing dye-doped phase change microspheres for enhancing solar-thermal utilization performance

A neoteric solar-thermal utilization and thermal storage microencapsulated phase change material (MPCM) material, RT60@silica (SiO2)/N719 (i.e. dye-doped MPCM), was prepared by in-situ polycondensation method including two steps: construction of O/W emulsion and dehydration polycondensation of TEOS with the participation of the N719 dye. The prepared composite material displayed a rapid visible-light-induced thermal conversion and solid-liquid phase transition promoted by the N719 dye which served as an effective visible-light photon capture additive enabling the direct and efficient use of solar radiation. The dye-doped MPCM slurry exhibits enhanced solar-thermal conversion performance, making it potential for use as the heat transfer fluid indirect absorption solar collectors. With high heat storage capability and excellent photothermal conversion performance, the prepared dye-doped MPCM composite is capable of developing its role in solar thermal energy storage applications.

Thermal properties of composite organic phase change materials (PCMs): A critical review on their engineering chemistry

The design of composite phase change materials (PCMs) for thermal energy storage has attracted increasing attention owing to their high latent heat storage capability, enhanced thermal transfer performance, and low volume variation in addition to being seepage free. This review aims to provide techniques for engineering the thermal parameters of composite PCMs (e.g., latent heat, thermal conductivity, durability, and thermal stability) for several advanced large-scale applications and for producing desired thermophysical, chemical, and mechanical properties. In addition, approaches and materials employed for composite synthesis are described. Challenges and factors influencing the thermal energy storage performance of composite PCMs are also analyzed. Furthermore, the recent advanced applications of composite PCMs (including medical, building, electronics, solar, and energy storage and conversion) as well as the potential for producing energy storage and conversion materials are indicated. This report is likely to provide a foundation for designing multifunctional organic composite PCMs.

Highly efficient solar-thermal storage coating based on phosphorene encapsulated phase change materials

Solar-thermal energy storage using latent heat of phase change materials (PCMs) offers renewable penetration in wide range of smart applications. The limiting solar energy harvesting efficiency of existing photo-thermal dopant materials and their negative impact on thermal storage capacity have remained fundamental impediment to further advancement. Herein, we explore a phosphorene based bandgap engineered broadband photonic nanoheater for efficient thermal charging of solid-solid PCMs. In our devised composite system, we benefitted from the synergistic effect of highly efficient photonic energy harvesting characteristic of exfoliated phosphorene nanoflakes (PNF) and latent heat storage capability as well as encapsulating feature of PCM matrix. The solar-thermal energy storage efficiency of our developed materials exceeds 95% even at lower phosphorene doping level (1 wt. %) and under full solar spectrum with improved latent heat storage capacity (150 J g−1). The achieved efficiency is highest among all photo-thermal storage materials and attributed to the intense and broadband solar absorbance of PNF featured by wide thickness distribution. Further, coating of developed solar heat storage material on fabric substrate has shown promising results toward real world applications.

Fabrication and characteristics of solar-driven phase change microcapsules with crystalline TiO2/CuS hybrid shell for solar energy conversion and storage

Abstract

A study on energy storage characteristics of industrial steam heating system based on dynamic modeling

The development of the industrial steam heating system has made power and thermal system more closely linked. Accordingly, the use of the steam network’s energy storage capability to improve the rapid load change capacity of thermal plants has become a new topic. The industrial steam heating system (ISHS) contains a large number of pipes and heat exchange equipment. The key is to understand the energy storage capability of the system by analogy and quantitative study. This study carries out the heat storage capability analysis of the industrial steam heating system through dynamic modeling. This study builds an actual pipe model in a chemical park by Modelica language and validates the model against field data collected on the site. The model deviation is less than 3%. Based on the validated model, this study carries out heat storage and discharge characteristics quantification by investigating three basic regulation modes: temperature regulation mode (quality regulation), the mass flow rate regulation mode (quantity regulation), and the hybrid mode. Through comparison, this study finds that the steam heating system has the highest analogized storage volume and longest heating discharge time under hybrid mode. From the perspective of utilizing system heating storage characteristics and saving the investment, hybrid regulation mode outperforms quality and quantity regulation mode. ISHS with hybrid mode has the potential to participate in short-term coordination control of electricity and heat in industrial parks.

Assessing the impact of diagenesis on foraminiferal geochemistry from a low latitude, shallow-water drift deposit

Due to their large heat and moisture storage capabilities, the tropics are fundamental in modulating both regional and global climate. Furthermore, their thermal response during past extreme warming periods, such as super interglacials, is not fully resolved. In this regard, we present high-resolution (analytical) foraminiferal geochemical (δ18O and Mg/Ca) records for the last 1800 kyr from the shallow (487 m) Inner Sea drift deposits of the Maldives archipelago in the equatorial Indian Ocean. Considering the diagenetic susceptibility of these proxies, in carbonate-rich environments, we assess the integrity of a suite of commonly used planktonic and benthic foraminifera geochemical datasets (Globigerinoides ruber (white), Globigerinita glutinata (with bulla), Pulleniatina obliquiloculata (with cortex) and Cibicides mabahethi) and their use for future paleoceanographic reconstructions.Using a combination of spot Secondary Ion Mass Spectrometer, Electron Probe Micro-Analyzer and Scanning Electron Microscope image data, it is evident that authigenic overgrowths are present on both the external and internal test (shell) surfaces, yet the degree down-core as well as the associated bias is shown to be variable across the investigated species and proxies. Given the elevated authigenic overgrowth Mg/Ca (∼12–22 mmol/mol) and δ18O values (closer to the benthic isotopic compositions) the whole-test planktonic G. ruber (w) geochemical records are notably impacted beyond ∼627.4 ka (24.7 mcd). Yet, considering the setting (i.e. bottom water location) for overgrowth formation, the benthic foraminifera δ18O record is markedly less impacted with only minor diagenetic bias beyond ∼790.0 ka (28.7 mcd). Even though only the top of the G. ruber (w) and C. mabahethi records (whole-test data) would be suitable for paleo-reconstructions of absolute values (i.e. sea surface temperature, salinity, seawater δ18O), the long-term cycles, while dampened, appear to be preserved. Furthermore, planktonic species with thicker-tests (i.e. P. obliquiloculata (w/c)) might be better suited, in comparison to thinner-test counter-parts (i.e. G. glutinata (w/b), G. ruber (w)), for traditional whole-test geochemical studies in shallow, carbonate-rich environments. A thicker test equates to a smaller overall bias from the authigenic overgrowth. Overall, if the diagenetic impact is constrained, as done in this study, these types of diagenetically altered geochemical records can still significantly contribute to studies relating to past tropical seawater temperatures, latitudinal scale ocean current shifts and South Asian Monsoon dynamics.

An experimental investigation of the effect of thermophysical properties on time lag and decrement factor for building elements

The time lag (TL) and decrement factor (DF) are essential for the heat storage capabilities of building elements, which strictly depend on the thermophysical properties of the elements. Many investigations are presented in literature arguing to find the influence of each thermophysical property on TL and DF by keeping the other properties constant. This study aims to investigate the effect of each property on TL and DF, utilizing relationships between the measurement values of the thermophysical properties of wall materials. Therefore, first, 132 new concrete wall samples were produced, and their thermophysical properties were tested. Secondly, TL and DF values for each building element are computed from the solution of the problem by Complex Finite Fourier Transform (CFFT) technique. Finally, a multivariate regression analysis has been performed, and the variations of each thermophysical property versus TL and DF are presented, and also the findings are compared with literature. The results show that each property alone (keeping the other properties constant) is not adequate to identify the thermal inertia and thermal performance of a wall element. Besides, 87.3 % decrease in thermal diffusivity corresponds to 6.03 h increase in the value of TL and 88.8 % decrease in value of DF; respectively, for W1 wall assembly.

Parametric evaluation of a hydrofoil-shaped sidewall rib-employed microchannel heat sink with and without nano-encapsulated phase change material slurry as coolant

The application of hydrofoil-shaped sidewall ribs (SWRs) in microchannel heat sinks (MCHSs) with nano-encapsulated phase change material (NEPCM) particle slurry as coolant has recently been proven as an improvised solution for enhancing heat transfer, with a reasonable penalty in pressure drop. However, the further mitigation of high-power densities of modern micro/nanoscale devices is limited owing to manufacturing complications and design constraints. By using the geometrical and thermophysical parameters of hydrofoil-shaped SWRs and NEPCM slurry, the present study numerically evaluates the thermal and hydrodynamic performance of an MCHS device. The preliminary results reveal the superior performance of NEPCM slurry with hydrofoil-shaped SWRs compared with that of water without ribs in an MCHS owing to the improved latent heat storage capability of the former fluid as well as the enhanced heat transfer area of the rib structure. Increase in the width and height of hydrofoil-shaped SWRs and particle diameter, latent heat of fusion and mass concentration of the NEPCM slurry at a constant Reynolds number (Re) and inlet temperature enhances heat transfer. However, increase in the pitch of the hydrofoil-shaped SWRs and melting temperature range of the NEPCM slurry degrades heat transfer. The inlet temperature of the NEPCM slurry, with a slightly lower value than the melting point of the NEPCM particles, yields superior performance. The maximum ratios of the Nusselt number, that is, Nuavg,SWR/Nuavg,ref and Nuavg,NEPCM/Nuavg,ref, are 1.88 and 2.68, respectively. A particle loading of more than 10% at a high Re of 1000 is not reasonable from the thermodynamic efficiency perspective. The findings are expected to serve as a benchmark for the selection of the geometric, thermophysical and operational parameters of future MCHS devices with hydrofoil-shaped SWRs and NEPCM slurry as coolant.

Latent heat thermal storage using salt hydrates for distributed building heating: A multi-level scale-up research

Latent heat storage using sodium acetate trihydrate is a promising heat storage technology for distributed building heating. However, the industrial and economic feasibility of this heat storage technology has not been proven yet. This work comprehensively carried out industrialization-oriented investigations on this technology from multi-level aspects of (i) thermal characterization and life-cycle assessment of industrial-grade storage materials, (ii) thermal design and performance evaluation of practical-scale heat storage equipment, and (iii) system integration and economic analysis of a practical heating project. The results indicate that the industrial-grade modified storage medium is of similar heat storage and transfer capability but a much lower cost, compared with the analytical reagent. However, it suffers from a more serious attenuation (7.3% vs. 4.9% after 300 cycles) in total heat storage capacity. The developed latent heat storage reservoir can perform stable charges and discharges, with a 24-h thermal loss of around 3.5%. The averaged storage thermal efficiency, total efficiency and specific operational cost of the electric-powered demonstration heating system within a 22-day continuous operation are 96.5%, 90.0% and 0.371 RMB (5.2 cents) kWh−1, respectively. The results prove a great application potential of latent heat storage using salt hydrates for the heat dispatch of distributed building heating.

The Heat Storage Capacities of Mortars Containing Clinoptilolite Blended Cements

Recently, the studies on the heat storage capabilities of building materials for energy efficient building design are becoming more widespread. In this study, the heat storage capacities of mortars produced with blended cement containing clinoptilolite that is the most valuanle of the natural zeolite minerals were investigated. The clinoptilolite which is used as replacement material and has the highest purity rate (96% purity) in the world was obtained from Manisa-Gördes region. Firstly, the mortar samples containing clinoptilolite blended cements at 0, 10, 30 and 50% replacement ratios were produced. And then, the physical, chemical, mechanical, petrographic properties, thermal conductivity and heat storage capacities of clinoptilolite rock were determined. The compressive strengths and thermal performance tests were performed on the mortar samples containing clinoptilolite blended cements. The test results were compared amongst themselves and with each other. According to the test results, it was concluded that heat storage capabilities of the mortars containing clinoptilolite blended cements could be improved.

Molecularly Imprinted Phase-Change Microcapsule System for Bifunctional Applications in Waste Heat Recovery and Targeted Pollutant Removal.

An innovative design of a molecularly imprinted phase-change microcapsule (MIM) system for bifunctional applications in waste heat recovery and targeted pollutant removal was reported in this work. This molecularly imprinted system was successfully constructed by encapsulating n-eicosane with a SiO2 base shell through emulsion-templated interfacial polycondensation and then coating a molecularly imprinted polymeric layer with bisphenol A (BPA) as a template molecule through surface free-radical polymerization. The morphology, microstructure, and chemical structure of the resultant molecularly imprinted phase-change microcapsules (MIMs) were characterized, and their phase-change behavior, thermal energy-storage performance, and selective adsorption capability were investigated intensively. The MIMs developed in this study achieved an outstanding latent heat-storage capability with a high capacity more than 165 J/g and also showed an excellent phase-change reliability with a very small fluctuation in phase-change temperatures and enthalpies after 500 thermal cycles. Moreover, the MIMs also presented a high thermal stability over 200 °C and good shape stability up to 120 °C. Most of all, an effective specific recognition capability and high recognition efficiency were achieved for the MIMs due to the formation of BPA-molecular imprinting sites on their surface. As a result, the MIMs exhibited good adsorption selectivity toward the BPA molecules and satisfactory reusability for targeted removal of BPA with a removal efficiency of 61.7% after 10 cycles of the rebinding-elution procedure. In view of a smart combination of thermal energy-storage and selective adsorption functions, the MIMs developed in this study demonstrate a great potential in applications for waste heat recovery and targeted pollutant removal of industrial and domestic wastewaters.

Cure Characteristics and Thermal Behavior of Organic–Inorganic Hybrid Composite as Assessed by DSC, TGA, and DMA Techniques

The current investigation reports the use of a residue from the iron metallurgy namely, “slag” to produce unsaturated polyester composite material-based slag (UPES). The slag has been mechanically treated by crushing and milling prior incorporating in the polymer. The role of the slag as co-curing agent of the polymerization reaction is studied under isothermal and dynamic conditions using differential scanning calorimeter (DSC); consequently, the role of the slag to enhance the thermal stability as well as the heat storage capacity of the UPE is reported. The isothermal cure temperature was varied from 80 to 120 °C, whereas the dynamic scan was run from room temperature to 250 °C at constant heating rate. This allowed us to estimate the degree of cure and cure rate. It has been found that incomplete cure was recorded by DSC for the pristine sample due to vitrification phenomenon. On the other hand, the sample with the slag displayed complete cure at 120 °C indicating that the heat storage capability of the polymer has been improved. The thermal stability of the samples was evaluated by a thermogravimetric analyzer coupled with a DSC unit. The sample containing slag responded better against thermal stimulation which was related to the mineral nature of the slag and the polar–polar interactions between the slag and the matrix. The interactions were attributed to the switch from hydroxyl–hydroxyl interactions to the formation of hydroxyl–slag (oxide). The interactions between the slag and the UPE resin were inspected using attenuated total reflectance infrared spectroscopy. The response of the samples to dynamic stimulation was evaluated by a dynamic mechanical analyzer. The sample containing slag displayed higher elastic moduli and broader tan (α) indicating better damping.