Integration Of Phase Change Materials Research Articles

Three-Dimensional CFD Analysis of a Hot Water Storage Tank with Various Inlet/Outlet Configurations

This study presents a comprehensive 3D numerical analysis of thermal stratification, fluid dynamics, and heat transfer efficiency across six hot water storage tank configurations, identified as Tank-1 through Tank-6. The objective is to determine the most effective design for achieving uniform temperature distribution, stable stratification, and efficient heat retention in sensible heat storage systems, with potential for integration with phase change materials (PCMs). Using COMSOL Multiphysics 5.6, simulations were conducted to evaluate key performance indicators, including the Richardson number, capacity ratio, and exergy efficiency. Among the tanks, Tank-1 demonstrated the highest efficiency, with a capacity ratio of 84.6% and an exergy efficiency of 72.5%, while Tank-3, which achieved a capacity ratio of 70.2% and exergy efficiency of 50.5%, was identified as the most practical for real-world applications due to its balanced heat distribution and feasibility for PCM integration. Calculated dimensionless numbers (Reynolds number: 635, Prandtl number: 4.5, and Peclet number: 2858) indicated laminar flow and dominant convective heat transfer across all the configurations. These findings provide valuable insights into the design of efficient thermal storage systems, with Tank-3’s configuration offering a practical balance of thermal performance and operational feasibility. Future work will explore the inclusion of PCM containers within Tank-3, as well as applications for heat pump and solar water heaters, and high-temperature heat storage with various working fluids.

Application of Taguchi design to optimize the operational parameters of pyramid solar still integrated with TiO2 nanoparticles

Abstract The global community is currently grappling with mounting concerns over the scarcity of fresh water, a situation that has emerged due to a complex interplay of various factors. One viable solution to address this issue is the use of renewable energy-powered water desalination. This study presents a thorough assessment of pyramid solar still (PSS) and its modified versions (MPSS) efficiency, which involves the integration of phase change material (PCM) and nano titanium dioxide (nTiO2) in the solar still. The experiments were conducted simultaneously under identical conditions for both the PSS and the modified still. Assessment of the MPSS was conducted, taking into account various operating parameters, including solar intensity (300–900 W m−2), water depth (4–8 cm), water inlet temperature (30 °C–50 °C), and the nTiO2 concentration (0.5–1.5 wt%). In addition, the Taguchi method was used to pinpoint the factors influencing the efficiency of the solar stills, as well as their respective levels. The signal-to-noise ratio and mean response were employed to identify the ideal levels of these parameters. Furthermore, the ANOVA method was utilized to assess the important factors and their impact on the overall production. Additionally, the regression method was employed to examine the type and magnitude of the correlation between the independent variables and the dependent variable. Finally, the estimated optimum production was compared to both the predicted productivity and the actual experimental productivity. An ideal condition was 900 W m−2 intensity of solar radiation, 4 cm depth of water, 50 °C of saline water temperature, and 1 wt% nTiO2 concentration.

Thermal uniformity analysis of a hybrid battery pack using integrated phase change material, metal foam, and counterflow minichannels

This study investigates the thermal performance and temperature uniformity of a hybrid battery thermal management system (BTMS) that integrates phase change material (PCM), metal foam, and minichannels. Computational fluid dynamics is used to model the PCM melting process and heat transfer between all components. The primary goal of the work is to investigate BTMS architectures which can enhance thermal uniformity and prevent critical temperature rise in a high-voltage battery pack under fast discharging and real-world driving cycle. Four BTMS designs are compared. The design that integrates PCM, metal foam, and counterflow minichannels is shown to have the best performance. At low pumping power (coolant Reynolds number Re = 10), this design reduces the peak battery temperature by 11.5 K compared to a design employing pure PCM only. This configuration also ensures a temperature difference of less than 5 K among individual battery cells, addressing thermal safety considerations and extending battery lifespan. Further analysis revealed that the inclusion of metal foam delays PCM melting, enhances both system and battery thermal uniformity, and offers a higher performance-to-weight ratio compared to designs without metal foam. Although wavy-shaped minichannels offer minimal temperature improvement (0.3 K) over straight minichannels, their higher cost and increased pumping power requirements do not justify their practicality. Under both fast discharging and real driving conditions, the first design with pure PCM provides uniform heat distribution within batteries but fails to maintain the maximum battery temperature within the optimal range. Overall, this study highlights the effectiveness of the proposed hybrid BTMS design in providing uniform temperature distribution and maintaining the maximum battery temperature within the optimal range under harsh environmental conditions, fast discharging, and the Urban Dynamometer Driving Schedule (UDDS) drive cycle.

Experimental study on the dynamic integration of PCM in building walls for enhancing thermal performance in summer condition

Passively integrating phase change material into the walls to enhance the thermal performance of the building has been a promising solution in recent years. As the PCM has a high latent heat capacity, it leads to damping the high variations of temperature and provides an obvious benefit in energy saving and indoor comfort. However, the traditional passive integration method of the PCM limited the utilization of the PCM. The thermal resistance between the PCM and the indoors restrains the thermal response of the PCM, and it between the PCM and the outdoors reduces the impact of outdoor heating or cooling on the PCM. In this study, a dynamic PCM integration in the building envelope method was proposed and experimentally investigated. A PCM layer and an air layer were combined to be integrated into the wall assembly, which allows the position of the PCM layer and the air layer could be changed to adjust the thermal resistance (air layer) between the PCM and indoors and outdoors. The results showed that this dynamic method can dramatically reduce the indoor temperature and the heat flux across the interior surface of the wall. Compared to the envelope with only static PCM layer configurations, the dynamic PCM provided a reduction of 9.1% in the indoor average temperature and a reduction of 116.0% in the peak heat flux during the experiment's three days, as well as the dynamic PCM, exploited more latent heat than the other static configurations. Considering the energy performance, the dynamic integration of PCM showed a 100% reduction in heat gain through the interior surface compared to the envelope with only a static PCM layer under summer conditions.

Sustainable commercially-scaled greenhouse building cooling solution: Integrating PCM storage, desiccant wheels, and absorption chillers powered by dual-source solar/biomass energy

This research aims to address the critical need for sustainable cooling systems in greenhouses, particularly relevant in mitigating global warming impacts and enhancing food security worldwide. The urgency becomes more pronounced in locations experiencing high ambient temperature and humidity. The study introduces an innovative cooling system integrating Phase Change Material, a desiccant wheel, and an absorption chiller, powered by solar and biomass energy. This novel system aims to efficiently regulate temperature and humidity in greenhouse environments. The performance of this system is examined in Abu Dhabi, Doha, and Riyadh during the summer months, utilizing TRNSYS software for a medium-scale greenhouse model. Additionally, a comprehensive Life Cycle Assessment is carried out to quantify the environmental impacts of the proposed system. Results indicate that in Abu Dhabi, the system yields a Coefficient of Performance (COP) of 1.108, effectively maintaining indoor climate conditions. Similarly, Doha and Riyadh exhibit COPs of 1.015 and 0.827, respectively. In terms of solar energy utilization, Abu Dhabi demonstrates a solar fraction of 40.4, corresponding to the lowest Global Warming Potential (GWP) at 0.106 kg CO2eq per 1 kW of provided cooling capacity. Conversely, Riyadh records the highest GWP at 0.149 kg CO2eq, followed by Doha at 0.118 kg CO2eq. The Energy Payback Time (EPBT) for the system in Abu Dhabi is calculated to be 3.96 years, the shortest among the examined cities. In comparison, Doha and Riyadh present longer EPBTs of 4.48 and 5.83 years, respectively. These findings suggest that the proposed system offers a viable and environmentally friendly alternative to conventional greenhouse cooling approaches.

Evaluating passive PCM performance in building envelopes for semi-arid climate: Experimental and numerical insights on hysteresis, sub-cooling, and energy savings

This study evaluates the performance of macro-encapsulated Phase Change Materials (PCMs) integrated into building envelopes for semi-arid climates, focusing on typical Moroccan construction using hollow concrete blocks. The primary objective is to assess the discrepancies between experimental and numerical analyses, particularly in hysteresis, sub-cooling, and energy savings. Given the widespread reliance on numerical tools like EnergyPlus for PCM simulations, the accuracy of manufacturer-provided latent heat values is investigated. The methodology involves constructing two identical test buildings, one equipped with PCM panels and another as a reference. Experimental data were collected in June 2023, assessing temperature fluctuations and energy savings. Differential Scanning Calorimetry (DSC) tests at varying scanning rates were conducted to analyze PCM behavior, including hysteresis and sub-cooling effects. Numerical simulations were then performed to compare energy performance. Besides, the results reveal that sub-cooling significantly limits PCM efficiency, with only 43 % of the PCM's latent heat capacity utilized. At the same time, hysteresis was found to be negligible in the field test. Cooling energy consumption was reduced by 20 %, with a corresponding 2.3 °C reduction in temperature fluctuations. However, the PCM's latent heat potential is underutilized due to sub-cooling. This research underscores the need for conducting DSC measurements at specific scanning rates to reflect regional climate conditions and suggests that simulation models should adjust latent heat utilization of the PCM. The study advocates for the use of composite PCMs, which could mitigate sub-cooling and enhance overall performance. These findings contribute to improving PCM integration in passive building designs, offering practical recommendations for better energy efficiency in semi-arid climates.

Innovative passive techniques and PCM integration in building envelopes for enhanced energy efficiency in desert regions

Rising energy demands in buildings for heating, cooling and operating appliances underscore the importance of implementing energy-efficient solutions. Passive cooling techniques provide a sustainable alternative to conventional, energy-intensive cooling systems, promising reduced energy consumption in buildings. Using a dynamic heat transfer model validated with ANSYS Fluent, this study examined three configurations: integrating phase change materials at the brick's centerline with cavities filled with air, EPS insulation, and emissivity coating. Additionally, the benefits of combining all three passive methods were evaluated. Results indicated that among the evaluated PCMs, capric acid demonstrated superior performance. While each passive method studied offers distinct advantages in enhancing thermal performance and achieving energy efficiency, assessing their combined effects revealed significant insights. Specifically, integrating capric acid at the brick's centerline, while simultaneously configuring EPS insulation in the upper cavities and emissivity coating in the lower cavities, yielded superior performance. This configuration significantly reduced inner surface temperature by approximately 6.6 °C and minimized heat flux by about 58.4 % compared to traditional bricks. Achieving energy savings of 56.24 %, this configuration shows potential to enhance both thermal comfort and energy efficiency in building applications.

Development of PCM tile for residential buildings in hot and dry climate: design and optimization

In recent years, the building sector has become more conscious of sustainability, and the use of phase change materials (PCMs) in concrete has gained more attraction. Integration of PCM with building facades is a successful method to reduce energy consumption and improve human comfort. However, no single PCM can work in an all-weather scenario. Hence, in this research work, an attempt is made to select a suitable PCM for Chennai city, India, and this methodology can be employed at any geographical location. The PCM tile is designed by including certain features to increase the thermal conductivity of the PCM zone. The optimum design of the PCM tile is achieved through multi-objective optimization techniques. L27 orthogonal array is employed, and all the tests were conducted through validated numerical simulation. Redesigned PCM tile includes a PCM layer of 2 cm thickness with a 10% mix of copper nanoparticles covered by plaster. Redesigned PCM tile reduces the peak indoor temperature by 6.62℃ compared with conventional roof systems.

Incorporation of Phase Change Materials in Buildings

This review paper explores the integration of phase change materials (PCMs) in building insulation systems to enhance energy efficiency and thermal comfort. Through an extensive analysis of existing literature, the thermal performance of PCM-enhanced building envelopes is evaluated under diverse environmental conditions. This review highlights that PCMs effectively moderate indoor temperatures by absorbing and releasing heat during phase transitions, maintaining a stable indoor climate. This paper also delves into the detailed concepts of PCMs, including their classification and various applications within building insulation. It is noted that different types of PCMs have unique thermal properties and potential uses, which can be tailored to specific building requirements and climatic conditions. Furthermore, cost–benefit and environmental assessments presented in the reviewed studies suggest that incorporating PCMs into building materials offers significant potential for reducing energy consumption and mitigating environmental impacts. These assessments indicate that PCMs can lead to substantial energy savings by decreasing the reliance on heating and cooling systems, thereby lowering overall energy costs and carbon emissions. However, despite the promising outlook, this review identifies a need for further research to optimize PCM formulations and integration methods. This optimization is essential for overcoming current challenges and facilitating the widespread adoption of PCMs in the construction industry. Addressing issues such as long-term durability, compatibility with existing building materials, and cost-effectiveness will be crucial for maximizing the benefits of PCMs in enhancing energy efficiency and sustainability in buildings. Overall, this review underscores the transformative potential of PCMs in building insulation practices. By providing a comprehensive overview of PCM classifications, applications, and their impacts on energy efficiency and environmental sustainability, this paper lays the groundwork for future advancements and research directions in the field of PCM-enhanced building technologies.

Experimental study on the effects of integrating phase change material with a solar updraft tower

AbstractThe solar updraft tower power plant presents a promising renewable energy solution but faces limitations in thermal efficiency and energy production during nonsunny hours. This study addresses a critical gap in the literature by investigating the integration of latent heat storage systems utilizing paraffin wax as phase change materials (PCMs) to enhance solar updraft tower (SUT) performance. Two identical small‐scale SUTs were constructed, both using the same tank configuration; however, the PCM device was filled with paraffin wax as a PCM, while the non‐PCM device contained only atmospheric air. Three scenarios were explored, featuring varying PCM tank heights of 2, 4, and 6 cm (the full capacity of the PCM tank). Results indicated that, from 3 p.m. until sunset, the PCM‐integrated SUT in Case 3 (with 6 cm of PCM) achieved the best performance, with an average absorber temperature rise of 25°C, compared with 12°C for the non‐PCM device. During the same period, the average air velocity at the tower neck, where a wind turbine could be installed, was 1.21 m/s for the PCM device, versus 0.82 m/s for the non‐PCM device. Notably, the nocturnal operating time extended significantly with PCM use, rising from 90 min for the 2 cm case to 125 min for the 6 cm case. In contrast, the non‐PCM device exhibited no operational time after sunset. This research not only demonstrates the effectiveness of PCM in improving the thermal performance and operational longevity of SUTs but also introduces a novel tank configuration that allows for flexible PCM integration, representing a significant advancement in the development of more efficient SUT systems.

Optimizing passive energy savings in rural self-built houses: Integrating phase change materials across China's climate zones

The energy consumption of rural residential buildings in China is increasing, and the integration of phase change materials (PCMs) has emerged as an effective strategy to mitigate building energy use and carbon emissions. Given China's diverse climate zones and the varying construction forms of rural self-built houses (RSHs), the efficacy of PCM applications varies significantly across regions. This study presents a comprehensive investigation into passive energy savings using PCMs in RSHs across various climate zones. We investigate the energy saving potential and thermal comfort effects of installing PCMs with varying phase change temperatures and thicknesses at different laying positions in representative buildings from each climate zone. The results indicate that the optimal phase change temperatures in different regions closely align with the outdoor average temperatures during the application season. When the optimal phase change temperatures and appropriate thicknesses of PCM are applied, cost-effective energy savings are consistently achieved in building roofing across regions, with the most significant effects observed in the Severe Cold region, where the uncomfortable degree hours reduction rate (φUDH) exceeds 90 %.

Integrating phase change materials in buildings for heating and cooling demand reduction – A global study

This study aims to analyse the integration of Phase Change Materials (PCMs) in building envelopes globally, focusing on its ability to reduce the energy demand and its economic viability. This study conducted extensive simulations using the DesignBuilder software across 5,684 locations globally and utilising artificial intelligence (AI) models to extend the simulation further to 73,515 locations, evaluating the impacts of PCM properties such as melting temperature (MT) and thickness. The main findings indicate that pronounced annual energy savings, 2500 to 3000 kWh, are observed in equatorial regions including northeast Brazil, central Africa, and the Malay Archipelago. Additionally, the optimal utilisation of increased PCM thickness is contingent upon selecting the correct MT and is most effective in regions with high average maximum temperatures, while the most common effective thickness is 20 mm. The study demonstrates that MT significantly affects energy savings, more than PCM thickness, highlighting the importance of selecting appropriate MT based on climatic conditions. The 25 °C MT is most effective within lower latitude range (−15° to 30°), averaging 743.2 kWh greater savings than the 21 °C option. The 21 °C MT shows superior performance outside of this range, however the advantage is marginal as the average savings is 251.0 kWh. Economically, regions such as the USA, southern Europe (Spain and Italy), Brazil, and northern Australia show the best viability for PCM integration, aligning energy efficiency improvements with substantial economic returns. This comprehensive analysis suggests that tailored PCM integration strategies are essential for maximising energy savings and advancing sustainable building practices.

Thermal characteristics of cementitious building materials with carbon and PCM for improved heat storage performance

The thermal properties of cementitious building materials were analyzed by integrating phase change materials (PCMs) and carbon materials to improve their heat storage performance. Four types of carbon materials, namely activated carbon (AC), carbon nanotubes (CNT), exfoliated graphite nanoplatelets (xGnPs), and graphene, were dispersed in PCMs and impregnated into artificial lightweight aggregates via vacuum impregnation to create cement building materials. Various parameters including compressive strength, differential scanning calorimetry (DSC), hydration heat, thermal conductivity, and dynamic heat transfer were evaluated According to the results, the thermal conductivity of PCM was significantly improved by incorporating carbon materials, and the specimen with CNT showed a result of 0.8386 W/m∙K, which is about 20 % higher than that of the specimen without carbon materials. Although the compressive strength decreased with the addition of PCMs, it remained above 20 MPa, thereby ensuring structural integrity. In the dynamic heat transfer test, the carbon/PCM specimen maintained a higher temperature during heat dissipation. It showed a high peak temperature and a time delay of about 2.5 hours during free cooling. The results showed that integrating PCMs and carbon materials into cementitious building materials could effectively improve their thermal performance, potentially saving building energy.

Achieving Off-Grid Refrigeration in Remote Areas: A Solar-Powered Vapor Compression Refrigerator Prototype with PCM Integration

The availability of vaccines, medicines, and perishable goods in remote or off-grid areas remains a formidable challenge. Integrating solar photovoltaic (PV) systems with refrigeration technology has emerged as a promising solution to address this critical need. This paper presents an autonomous solar-powered refrigerator prototype for off-grid refrigeration in remote areas utilising renewable energy. The system comprises a 160 W photovoltaic module, a 12/24 V DC compressor refrigerator, a lead-acid battery, and a Maximum Power Point Tracking (MPPT) controller. Its main feature is complete autonomy from the electricity grid, thanks to its standalone configuration. An experimental campaign evaluated the system's behaviour in the laboratory for 24 hours at different set-point temperatures. A water-based Phase Change Material (PCM) was implemented to improve its autonomy in severe outdoor conditions. A further experimental campaign emulated the functioning of the prototype while managing the temperature of a sample solution whose melting temperature was equal to – 21°C to ensure its liquid state during the tests. The target range for preserving the sample was defined at ± 1°C. Several real conditions have been considered, such as higher cooling loads realised through 21 litres of additional thermal mass in the refrigerator and pick and place conditions for simulating the opening and closing of the door. The results demonstrate that the solar refrigerator prototype achieves complete autonomy from the electricity grid, paving the way for solutions for preserving perishable goods such as medicines and food in unelectrified areas.

A comparative analysis of the carbon footprint in green building materials: a case study of Norway.

This paper critically examines the carbon cycle and environmental impacts associated with building materials, encompassing diverse impact categories for both midpoint and endpoint scenarios. The research encompasses a comparative analysis of five distinct scenarios, contrasting the environmental performance of green against conventional counterparts. Notably, previous research endeavors did not investigate the effects of varying percentages with and without phase change materials (PCM). The primary objective is to assess the impact of integrating phase change materials (PCM) with varying percentages of fly ash (20% and 35%) on energy consumption and carbon emissions, particularly in cold climates like Norway. The study employs the ReCiPe2016 Midpoint (E) method, which offers a robust life cycle assessment (LCA) framework aligned with European standards, making it particularly suitable for this context. Energy Plus, within the Design Builder software, was used to simulate and calculate the impact of PCM on energy efficiency. The findings underscore those environmental impacts attributed to green buildings amount to 9.79 × 104 kg of CO2 equivalent, while conventional buildings account for 1.04 × 105 kg of CO2 equivalent. Furthermore, among the cases studied, the optimal scenario pertains to a green building utilizing 35% wind ash cement and PCM, resulting in the equivalent of 9.68 × 104 kg of CO2 emissions. Remarkably, the best-case scenario involves a green building boasting a robust steel interior structure and aluminum windows, whereas the worst-case scenario entails a typical building devoid of PCM implementation. Furthermore, energy consumption analysis indicates that scenario 5, which utilizes PCM and 35% fly ash, achieves a 15% reduction in cooling energy and a 6.9% reduction in heating energy compared to scenario 3, resulting in an annual energy consumption of 97,453.09 kWh.

Thermal performance of multifunctional louver window integrated phase change material and spherical louver

The integration of phase change material (PCM) into glazed envelope is an effective measure to enhance its thermal inertia and reduce energy consumption. However, the inefficient utilization of latent heat stored in double-glazed unit filled with PCM (PCMW) in winter and overheating in summer restricts the adoption of PCM in cold regions. Therefore, this work proposed a multifunctional new phase-change louver window integrating PCM and spherical louvers, and numerically investigated its thermal behaviour in summer and winter seasons. The effects of different melting temperatures and ventilation mechanisms on the thermal performance and energy efficiency of phase change louvers were analyzed. The results show that the new phase-change louver window can significantly improve the thermal comfort and energy efficiency of the window. In winter, insulated PCM louver window has the best performance, reducing heating energy consumption by 2618.56kJ/(m2·d) compared to hollow window, with energy saving of 54.03 %, whereas in summer, reflective PCM louver window performed best, reducing cooling energy consumption by 3584.47 kJ/(m2·d) compared to hollow window, with an energy saving rate of 37.08 %. The analysis of various melting temperatures shows that the melting temperature of RT14 is the most suitable in the annual basis, and the introduction of ventilating mechanism for ventilated reflective PCM louvers window can significantly enhance the performance of the window.

A Review of the Energy-Saving Potential of Phase Change Material-Based Cascaded Refrigeration Systems in Chinese Food Cold Chain Industry

As the global demand for food increases, the efficiency and environmental sustainability of refrigeration systems have become increasingly critical issues. Cascaded refrigeration systems (CRSs) are widely used in the Chinese food cold chain due to their capacity to meet a wide range of temperature requirements. However, energy consumption of these systems is always high. If phase change materials (PCMs) are combined with the refrigeration systems, the energy-saving effect is remarkable. The paper reviews the integration of PCMs within CRS, focusing on their potential to reduce energy consumption, thereby improving food safety and reducing reliance on conventional, electricity-intensive refrigeration methods. The study categorizes and explores the low-temperature applications of PCMs in CRS, providing novel insights into enhancing energy efficiency in food cold chain logistics. Despite most PCM research focusing on single-stage systems, this review innovates by introducing PCM integration in multistage cascade systems, which is particularly relevant for low-temperature requirements. The discussion encompasses the structure, working fluids, and applications of CRSs in the cold chain, emphasizing the role of PCMs in sustainable cold chain management. The review concludes by highlighting the need for further research on PCMs in CRS, especially regarding their economic viability and large-scale implementation potential.

Experimental investigation of distilled water production performance of conventional solar stills using CaCl2·6H2O phase change material reinforced with SrCl2·6H2O and graphene-based nanoparticles

This study aims to enhance the performance of conventional single-slope basin-type solar stills by integrating phase change materials (PCMs) and nanoparticles. Calcium chloride hexahydrate, known for its high heat storage capacity, was selected as the primary PCM. Strontium chloride hexahydrate was added as a nucleating agent to address the supercooling tendency. Additionally, graphene oxide (GO) and graphene nanoplatelets (GNP), which have not been previously used in solar stills or compared for their performance, were incorporated into the PCM to utilize their photothermal properties and enhance solar energy absorption. The integration of GO and GNP with the PCM-nucleating agent combination resulted in daily total distilled water productions of 5424ml/m2 and 5032 ml/m2, respectively. The integration of GO with the PCM-nucleating agent combination provided the most significant improvement in efficiency, with a 54.44 % increase compared to the standard still, a 15.4 % increase compared to the still using only the nucleating agent, and an 8 % increase compared to the still incorporating GNP.

Fabrication and building energy-saving performance evaluation of polyethylene glycol/polymethyl methacrylate/expanded graphite thermal enhanced shape-stable phase change material

Integrating Phase Change Material (PCM) with building envelope is a promising way to reduce building energy consumption. However, leakage and insufficient PCM loading rate for existing encapsulation strategies limit its further application. In this work, a safer and easier way to fabricate Shape-Stable Phase Change Material (SSPCM) is proposed, whose products combine the outstanding leakage-proof property and high PCM loading rate. With the method of in-situ polymerization, not only the Polyethylene Glycol (PEG) is packaged by Polymethyl Methacrylate (PMMA), but the Expanded Graphite (EG) also has a chance to be added as the property regulator. The prepared SSPCMs are proved to be shape-stable over melting temperature with a leakage rate under 1 %. The characterization test reveals that with EG mass fraction increase from 0 to 2.5 %, the thermal conductivity augments from 0.23 to 1.73 W/(m·K) while the phase change latent enthalpy changes from 85.11 kJ/kg to 116.10 kJ/kg. Notably, the EG is more than a thermal conductivity enhancer, it also plays an important role in the modification of comprehensive properties. To optimize the building energy-saving performance of SSPCMs, the factors affecting building cooling electricity consumption like deployment position and thermal properties are evaluated in detail. The simulation results show that the optimum strategy is employing SSPCM with 2.0 wt% EG in the middle of the envelope, the cooling electricity consumption can be reduced by 8.64 % compared with the benchmark. The physical mechanism of energy-saving is also discussed from multiple angles. From a statistical view, sensitivity and uncertainty analysis of the simulation results is completed, to identify the influence of input parameters and validate the reliability of the simulation results. Finally, an economic analysis is carried out, proving the economic feasibility for further application. This research provides valuable insights for SSPCM’s application and design of energy-efficient buildings.

Thermal energy storage using phase change material for solar thermal technologies: A sustainable and efficient approach

Over-exploitation of fossil-based energy sources is majorly responsible for greenhouse gas emissions which causes global warming and climate change. To mitigate these challenges renewable energy sources, especially solar thermal technologies, can play a decisive role. United Nations also proposes steps to attenuate the adverse effects of fossil-based energy and climate change through Sustainable Development Goals (SDG7 and SDG8). Solar thermal technologies have seen a huge capacity expansion around the globe in previous decades because of their inherent advantages. However, solar energy faces crucial limitations of fluctuating intensity and time-dependent availability. This decreases solar thermal system performance and makes solar thermal technologies time-dependent. To overcome these challenges, integrating phase change material (PCM) in solar thermal technologies makes a sustainable approach to enhance the efficacy, productivity, and utilization rate of solar thermal technologies. In this manuscript, the sustainable approach of integrating PCM in solar thermal technologies was reviewed. This includes literature on PCMs which covers classification, properties, importance, and limitation. Comprehensive data on the integration of PCM with solar thermal technologies such as solar water heating, solar desalination, solar cooking, solar dryers, solar PV/T, solar ponds, solar chimneys, and solar power plants were reported explicitly in terms of the type of PCM, efficiency and their productivity. In addition, the effect of PCMs integration in solar thermal technologies was analyzed in terms of mitigation of CO2 emissions and economic analysis at different locations around the World.