Phase Change Materials In Buildings Research Articles

A comparative evaluation on energy consumption of a building using bio-based and paraffin-based phase change materials integrated to external building envelope

Using thermal energy storage such as phase change materials (PCMs) is a suitable solution to reduce energy consumption in order to maintain thermal comfort conditions inside the building. There is a wide range of phase change materials according to their different characteristics such as melting temperature, freezing temperature, latent heat capacity, specific heat value of solid and liquid phase, thermal conductivity coefficient, and charge and discharge range, which makes it difficult to choose the right PCM. In this research, two common groups of phase change materials that are used commercially are studied and after performing a sensitivity analysis on them, a suitable temperature range is selected. Then the selected PCMs are placed in different parts of the external envelopes of the building and various parameters such as air conditioning system energy consumption, thermal comfort, heat balance, etc. are examined. It should be noted that in this study, the use of PCMs in buildings with cooling and heating systems is investigated. In order to carry out the simulation, a two-story office building located in Arak, Iran was modeled in Design Builder software along with all the details. The outputs show that if Bio PCM is used in the outer layer of the wall in the summer season, it is possible to save up to 154 w/m2 in the energy required for cooling the building. While the use of Bio PCM M91 Q21 material in the inner layer of the wall will reduce the load of the cooling system by 246.15 Wh/m2. Also, if RT PCM is used, it is possible to reduce the heat load by 80%. Furthermore, by analyzing the optimal cases, it can be concluded that increasing the thickness of the PCM layer cannot effectively improve the thermal performance of the building. On the contrary, their reduction in some cases leads to a reduction in energy demand in the building. Finally, in order to generalize the results, the optimal situation was compared with two similar climates of Arak city.

Molecular dynamics study of paraffin/polyethylene blends as phase change materials for energy efficiency in buildings

ABSTRACT The greenhouse gas emissions and global energy consumption associated with construction materials can be greatly reduced by incorporating phase change materials into buildings. These materials can absorb and release energy during a phase transition, thus reducing the energy consumption while achieving human thermal comfort. Molecular dynamics simulations were used to study the miscibility of both linear and branched polyethylene with two types of paraffin (octadecane and hexatriacontane) at two different temperatures. The results showed that blending was better at high temperatures for both polymers, and branched polyethylene was more miscible with both paraffins than linear polyethylene was. Hexatriacontane exhibited better blending characteristics. From the molecular dynamics results, we concluded that linear polyethylene/paraffin blends were more suitable as phase change materials in buildings than branched polyethylene/paraffin blends, as they were miscible at high temperatures but separated into two phases at ambient temperature. The optimal blends were subsequently incorporated into a cement model to study their influence on the mechanical properties of this construction material. The introduction of the blends into the cement model deteriorated its mechanical properties.

Optimization study on thermal performance of a novel dynamic phase change material wall

A new concept of dynamic phase change material (PCM) wall structure in building envelope is proposed to enhance the passive solar energy utilization, in which PCM wall position could be exchanged with insulation layer. The thermal performance of phase change materials in buildings is related to many factors. To ensure that the novel dynamic PCM wall structure could reach its full potential, the thermal performance of the structure was numerically simulated and optimized based on different climatic conditions, room sizes and the position of PCM layer in the wall. The results indicated that the suitable PCM was different when using the novel dynamic PCM wall in different climates. Among the four cities of Harbin, Tianjin, Jinan and Guangzhou, northern cities, like Tianjin, were more suitable for using PCM A16 than southern cities. In terms of room size design, when the volume of the room remained identical, the room size design formed a certain correlation with the indoor temperature. In addition, results showed that the location of the novel PCM wall system in the wall would cause a great difference in indoor temperature, which was related to heat dissipation at different locations.

Performance evaluation of different building envelopes integrated with phase change materials in tropical climates

The need to improve building envelope components and reduce energy consumption is becoming increasingly crucial. The use of phase-change material (PCM) technologies is a viable solution to reduce energy consumption in buildings and associated greenhouse gas emissions. However, the performance of PCMs in buildings is strongly dependent on the melting temperatures and the climate conditions of the building's location. Therefore, the present study presents an optimisation-based approach to assessing the performance of building walls integrated with PCMs at different melting temperatures. To achieve this goal, a multiobjective genetic algorithm is used in conjunction with EnergyPlus building energy models to determine the optimal balance between total building energy consumption, lifecycle cost, and CO2 emissions. The proposed approach is applied to a single-family residential building located in six locations in the Central African sub-region classified as tropical savanna climate (Aw), hot semi-arid climate (Bsh), tropical rainforest climate (Af), and tropical monsoon climate (Am). Two different PCM technologies (InfiniteRPCM and BiocPCM) are applied to four wall types (brick, concrete block, cast concrete, and earth), and their parametric models are developed in EnergyPlus to optimise the melting temperature, thickness, and location of each PCM layer simultaneously. An optimisation is conducted for each selected wall and each location, and the optimised buildings are systematically compared to the reference buildings. The optimisation results showed that regardless of the climate zone and wall type, the application of PCMs with different melting temperatures significantly reduced energy consumption and CO2 emissions. Moreover, the results showed a different set of optimal solutions for each climate zone and wall type. The optimal solutions reduced the total energy, life cycle cost, and CO2 emissions by up to 47.80 %, 29.62 %, and 52.96 %, respectively.

Incorporating phase change materials in geothermal energy piles for thermal energy storage

Introduction
 Geothermal energy piles (GEPs) are foundation elements that are installed in the ground to support the weight of the building to a competent strata. Energy loops are installed into the piles to allow heat rejection or extraction via the circulation of fluid through the loops. In winter, low-grade heat is extracted from the ground (source) and transferred to the building (sink) to achieve space heating. Conversely, in summer, heat is removed from the building and rejected into the ground to achieve space cooling. The system relies on the temperature gradient between the ground and the ambient air temperature; where in winter, the ground temperature is higher than the air temperature, while in summer, the opposite is true. Thus, the system can sustainably and continuously supply the heating and/or cooling demand of a building once the temperature gradient between the ambient air and the ground is maintained. To improve the sustainability and performance of the system, the heat energy rejected into the ground can be stored and used at a later time when space heating is required [1]. Energy storage substances such as phase change materials (PCMs) can be incorporated into energy piles to store the heat that is rejected into the ground to improve the performance of the GEP system [2]. PCMs are materials that stores or releases heat energy during phase transition. Many researchers including [3,4] have reported using PCMs in buildings to improve thermal comfort and minimise the energy demand during heating and cooling periods, however, not much work has been done with regard to incorporating them into pile foundations to improve the performance of GEP systems.
 Thus, this study carried out a laboratory experiment to investigate the effect of the addition salt hydrate PCM on the energy performance of geothermal energy piles.
 Laboratory test and procedure
 In this study, lab-scaled models of energy piles were constructed, with and without PCM. The piles are characterised by a length and a diameter of 300 mm and 100 mm, respectively. In order to add PCM into the piles, the PCM was encased and sealed in a PVC tube with an inner and an outer diameter of 6mm and 8mm, respectively. The same size of PVC tube was used for the energy loops. The energy loop (U-shape), and the encased PCM incorporated tubes are attached together and placed in the mould prior to concreting, for the pile model with PCM (see Figure 1a). Whereas only the energy loop was installed in the control sample.
 In the test setup, a layer of sand (220mm thick) was placed and compacted in an insulated wooden box (520mm × 520mm × 520mm). Afterwards, the pile was then installed at the center of the box and then filled with sand, in layers and compacted. An insulation sheet was used to cover the top of the box to prevent heat loss and the ambient air temperature influencing the tests’ results. Water at a temperature of 32°C, was circulated through the pile continuously for a duration of 4 days (96 hours). Instrumentations were installed in the pile and soil to monitor and record the changes in temperature during the tests (see Figure 1b).
 Results and discussion
 Figure 1c shows the results comparing the average energy rejected, and stored, in the ground for the piles with and without PCM. The maximum heat energy stored at the beginning of the test was found to be about 460W and 360W for the control and PCM piles. However, at the end of the tests, the energy stored was 230W and 430W for the control and PCM pile, with an average energy stored as shown in Table 1. The addition of salt hydrate PCM absorbs the heat rejected into the pile, consequently improving its thermal performance by about 22% in comparison to the control pile. Similarly, the magnitude of temperature developed in the pile and surrounding soil were observed to be lower in the pile with PCM. This can ultimately reduce the induced stresses and strains induced in a pile due to heat energy extraction or rejection.
 
 Conclusion
 This paper investigated the feasibility of using salt hydrate PCM in energy piles for heat storage. It was found that the energy rejected in a pile with PCM increases by up to 22% compared to a non-PCM pile.

A Review of Solar-Coupled Phase Change Materials in Buildings.

Buildings use a significant percentage of the total energy consumed worldwide. Striving for energy conservation within buildings is of prime concern for researchers. Hence, scientists are aggressively exploring new energy storage and supply methods to reduce exorbitantly fluctuating energy demands and increase the share of renewable energy in building energy consumption. Solar systems that incorporate phase change materials (PCMs) for thermal storage have significant potential to serve in this context. These systems are not yet able to endure the significant energy demands, but they are being continually improved. The aim of this paper is to explore the existing solar PCM systems that are being studied or that are installed for use in indoor heating/cooling. As per the outcome of this systematic review, it has been observed that when coupled with solar thermal energy, the configuration of PCMs can either use passive or active techniques. Passive techniques are usually less efficient and more costly to implement in a building structure, resulting in active heat exchangers being widely implemented with better technical and economic results. At the same time, it has been observed that for most domestic buildings, organic PCMs with phase change temperatures of up to 42 °C and thermal conductivities of up to 0.56 W/m.K are most suitable for integration in solar thermal energy production. Hybrid systems are also commonly used for larger commercial buildings, in which the solar PCM system (SPCMS) provides a fraction of the total load. Additionally, the Stefan number is the most common technical parameter that is used to assess this performance, along with the effective thermal conductivity of the PCM after using enhancement techniques. The key economic indicator is annual savings per year, with most SPCMSs having a payback period of between 6 to 30 years. This review provides designers and researchers with key insights in terms of formulating a basis in the domain of coupling PCMs with solar thermal energy, especially within non-industrial buildings.

Experimental and numerical investigations on the influence of phase change materials on heat transfer reduction across the roof of a building

ABSTRACT Faced with the problems of increasing energy scarcity and ongoing environmental deterioration, phase change materials (PCM) have attracted a lot of attention recently for improving building energy performance. Utilizing the PCMs in buildings is one of the efficient approaches to reduce the heat penetration into the buildings. In this work, the thermal performance of a building equipped with PCM roof is analyzed and compared with a plain roof building. The uniqueness of this study is to analyze the effect of PCM experimentally and numerically through parametric investigation with different PCMs (HS29 and OM29), encapsulation materials (aluminum and steel) and PCM thickness. The experimental analysis shows that the PCM incorporated roof decreased the inner room temperature of the building by 2°C vis-à-vis plain roof and hence helps reduce the cooling load and enables passive cooling of the building with energy savings. A numerical analysis was carried out using COMSOL and validated with maximum and average errors of 7.43% and 4.87% respectively. The parametric investigation from the validated model indicates that the PCM OM29 is effective compared to HS29 in terms of temperature reduction. The steel encapsulating panels are observed to be better than aluminum at the peak sunshine hours while the aluminum panel is effective for the other periods. It is observed that the increase in PCM thickness augments the reduction in heat transfer while the 6 cm PCM thickness showed a higher temperature reduction by 3.6°C vis-a-vis 2 cm PCM thickness.

Impact of gypsum mortars functionalized with phase change materials in buildings

The construction industry needs to adopt raw materials with less environmental impact and functional raw materials. The utilization of phase change materials (PCM) in interior mortars allows the energy efficiency of buildings improvement, based on solar energy, a renewable and clean energy source. On the other hand, the selection of mortars based in binders whose production emits lower carbon dioxide emissions than cement, like gypsum, can be a promising solution in help to minimize carbon dioxide (CO2) emissions and the energy consumption for raw materials production. The main objective of this work was the development and characterization of gypsum-based mortars functionalized with PCM. Four distinct mortars were developed with different contents of pure and non-encapsulated PCM (0 %, 5 %, 10 % and 20 %). The different mortars were tested from a physical and mechanical point of view. The thermal performance of the mortars according to the summer and spring seasons of the north part of Portugal and an economic analysis of the application of these mortars in a typical Portuguese building were also carried out.The results obtained allow to observe that the incorporation of 20 % PCM leads to a decrease in the water absorption by capillarity, water absorption by immersion, flexural and compressive strengths of about 65 %, 30 %, 47 % and 59 %, respectively. However, its applicability has not been compromised. The thermal performance of the PCM mortars was improved, based in the temperature range and heating and cooling needs decrease. Regarding to the summer season it was observed a maximum temperature decrease of 2.3 °C, a minimum temperature increase of 2.6 °C and a decrease of cooling and heating needs of 13 % and 21 %, respectively. Concerning to the spring season it was verified a maximum temperature decrease of 2.7 °C, a minimum temperature increase of 1.9 °C and a decrease of cooling and heating needs of 100 % and 16 %, respectively. The cost analysis revealed savings in electricity costs for buildings climatization of around 17 % during the summer season and around 59 % during the spring season.

A Review of Recent Improvements, Developments, and Effects of Using Phase-Change Materials in Buildings to Store Thermal Energy

When it comes to guaranteeing appropriate performance for buildings in terms of energy efficiency, the building envelope is a crucial component that must be presented. When a substance goes through a phase transition and either gives out or absorbs an amount of energy to provide useful heat or cooling, it is called a phase-change material, or PCM for short. Transitions often take place between the matter’s solid and liquid states. Buildings use PCMs for a variety of purposes, including thermal comfort, energy conservation, managing the temperature of building materials, reducing cooling/heating loads, efficiency, and thermal load shifting. Improved solutions are applied using new method and approach investigations. Undoubtedly, researching and applying PCM use in building applications can help create buildings that are more energy-efficient and environmentally friendly, while also increasing thermal comfort and consuming less energy. It provides a possible answer to the problems posed by climate change, rising energy demand in the built environment, and energy use optimisation. However, it is true that no particular research has yet been conducted to thoroughly analyse the linked PCM applications in the building industry. Thus, the principal tactics are addressed in this paper to determine current and efficient methods for employing PCMs in buildings to store thermal energy. By gathering around 50 instances from the open literature, this study conducts a thorough assessment of the up-to-date studies between 2016 and 2023 that used PCMs as thermal energy storage in building applications. As a result, this review aims to critically evaluate the PCM integration in buildings for thermal energy storage, identify a number of issues that require more research, and draw some important conclusions from the body of literature. Specifically, the building envelope roof and external wall uses of PCMs are highlighted in this research. Applications, general and desired characteristics, and PCM types and their thermal behaviour are described. In comparison to a traditional heat storage tank that simply contains water, this review indicates that a water storage tank containing 15% PCM improves heat storage by 70%. Also, less than 7 °C of internal air temperature was reduced by the PCMs in the walls, which avoided summer warming. Finally, using PCM for space cooling resulted in substantial energy savings across the various seasons.

Investigation of the impact of phase change materials at different building envelope placements in a semi-arid climate

Researchers in the building industry are becoming increasingly interested in phase change materials (PCM). Due to the potential for passive temperature management offered by these PCMs, HVAC (Heating, Ventilation, and Air-Conditioning) equipment will use less energy. Still, to prevent leakage during phase change, an enclosure is needed when installing PCMs in buildings. So, to determine this passive indoor temperature regulation cost, payback period, and energy savings, it is crucial to assess the PCM energy savings in various building envelope placements. So, this is done by using the EnergyPlus simulation engine for the case of the commercial PCM RT 28HC, this article will assess and compare 8 potential building envelope positions in a semi-arid region. These eight different building configurations have one case without PCM and the other cases have PCM placed in the interior surface of the following specific placements, a PCM placed in walls envelope only, in floors envelope, in ceilings and roofs envelope only, in walls, ceilings, and roofs envelope, in walls and floors envelope only, in floors, ceilings and roofs envelope and all envelopes for a 10 m square-shaped building. This study's primary goal is to evaluate the reduction of indoor air temperature fluctuations, PCM energy savings, PCM activation, and payback period for these various building layouts. The findings show excellent temperature indoor stabilization in summer, for the case with PCM installed on all interior envelope surfaces showing a maximum indoor temperature fluctuation decrease of 110.2 °C for August. In addition, the case with the PCM placed only in the walls, roof, and ceilings has shown the highest yearly energy savings, nevertheless, the case with PCM placed only in the walls has the lowest payback period of nearly 22 years and a half.

Multi-objective optimization of latent energy storage in buildings by using phase change materials with different melting temperatures

Technologies based on phase change materials (PCMs) are promising solutions to reduce energy consumption in buildings and related greenhouse gas emissions. However, the performance of passive PCMs in buildings is highly dependent on the melting temperatures employed, as well as the climate where the building is located. Therefore, the present contribution describes an optimization-based method to design passive latent energy storage in buildings by using PCMs with different melting temperatures. To achieve this goal, a multi-objective genetic algorithm is coupled with the building energy models developed in EnergyPlus to find the best trade-off between annual heating and cooling loads. A small office is chosen as a case study to evaluate the energy performance of the buildings incorporating the proposed PCM approach. Three different PCM layers are added to the ceilings and the external and internal walls of the building, and their parametric models are developed in EnergyPlus to optimize the melting temperature and thickness of each PCM layer simultaneously. Moreover, a method to select climate-representative locations according to the ASHRAE 169-2020 climate classification and within the WMO Region VI (Europe) is proposed and applied, resulting in eight well-representative locations. An optimization-based design is carried out for each selected location and the performances of the optimized building designs are systematically compared to the ones of the baseline models. The optimization results achieved show that regardless of the climate zone analyzed, using several PCMs with different melting temperatures instead of a single one, is preferred. Moreover, the best performance of PCMs is attained in climate zones where both the heating and cooling loads are present. Thus, the highest saving regarding the annual total loads of 11.7% is achieved in zone 5A (Cold), while the lowest one of 2.3% is obtained in zone 1B (Very hot).

A conceptual framework for phase change material integration in building components

With the recent dramatic growth of the building sector’s energy consumption to provide thermal comfort to consumers, the constraints of climate change and the scarcity of energy supplies have necessitated a wiser and more effective reduction in the amount consumed. As a result, phase change materials (PCMs) have attracted much interest as latent heat thermal storage systems in recent decades. This paper aims to explain the possibility of using PCMs in buildings by establishing an overall conceptual framework for the processes of selecting and integrating PCMs in building sector applications. Moreover, it leads to a comprehensive matrix that identifies the best and most common type of material for each building’s component, as well as its temperature and thickness properties, its thermal impact, and the most popular integration techniques. The findings show paraffin as the major used type in all building components, while salt hydrate is employed in facades. The most prevalent incorporating technique is macro-encapsulation, which prevails in most building components with its direct effect on cooling and heating applications.

Optimization of double-layer shaped phase change wallboard in buildings in two typical climate areas in China

Phase change material (PCM) applied in buildings can significantly improve thermal comfort and realize building energy conservation. In recent years, double-layer shaped phase change wallboards (DLSPCWs) that depends on the latent heat absorption and release of two kinds of PCMs can effective control the indoor temperature fluctuation, and have been play an important role in improving the indoor thermal environment. The related researches show that, it is rare but necessary to optimize the DLSPCWs in different typical climate areas in order to further promote the application development of PCMs in buildings for energy conservation. Aimed this, fifty-four different DLSPCWs were constructed in this study by selecting different phase change thermal storage layer from four kinds of form-stable PCMs and changing the thickness of the layer to optimize the structure of DLSPCW in two typical climate areas, including severe cold area (Xining city, China) and hot summer and warm winter area (Haikou city, China) respectively. Comsol Multiphysics was used for heat transfer simulation and calculation of the DLSPCW in order to determine its best structure combination pattern for the two areas, and DesignBuilder for comparing and analyzing the building energy conservation effect when using the optimal DLSPCW in buildings. Compared with the ordinary wall, the optimized DLSPCW saved 14,198.96 kW·h electric energy during the heating period in Xining, while 18,816.62 kW·h electric energy in Haikou during the cooling period. The results proved that the optimum structure of the DLSPCW not only reduced the heating load and the cooling load but realized the maximum utilization of the PCMs.

Investigation of the appropriate phase change temperatures for an enhanced passive indoor thermal regulation in a semi-arid climate: Tunable PCM case

Researchers in the building industry are becoming increasingly interested in phase change materials (PCM). As these PCMs might provide passive temperature adjustment, this will aid in lowering the energy consumption of Heating, Ventilation, and Air-Conditioning (HVAC) devices. To prevent leakage during phase change, an enclosure is needed when installing PCMs in buildings. The need to assess the passive thermal regulation of the PCMs at different melting temperature is necessary, so that we can get a sense of how much energy will be saved for this passive thermal regulation method. Hence, this paper will evaluate and identify the optimum phase change transition temperatures during the whole year for wall composition with tunable PCM in a semi-arid climate. Thus, the main objective of this study is to assess the indoor air temperature fluctuation reduction and the PCM activation while suggesting an appropriate phase change transition temperature that can be beneficial in the whole year and very practical. The results reveal a good passive temperature regulation during the summer period.

Energy and thermo-economic analysis of PCM integrated brick in composite climatic condition of Jaipur - A numerical study

Use of phase change materials (PCM) in building to enhance thermal comfort and reduce energy consumption has widened over last few decades. Various techniques are employed to incorporate PCM in buildings, to reduce cooling/heating loads and temperature fluctuations in buildings owing to its high latent capacity. Present work investigates the thermal performance of n-Eicosane and OM35, incorporated in clay bricks, a widely used construction material. Numerical study is performed to analyse the energy saving potential for varying PCM positions and thicknesses to optimize the configuration. The optimized configuration is analysed for reducing indoor heat flux under unconditioned, partial and fully conditioned indoor environments. The annual thermal performance of the optimized configuration is studied for estimation of monthly heating/cooling load and total annual energy savings. Economic analysis is conducted to determine the energy saving cost and payback period for the design in different wall orientations under different indoor conditions. Results showed that OM35 in East orientation provided cooling load reduction of 31.1% for May which is equivalent to annual cost saving of USD 1.05/m2, while North orientation with n-Eicosane provided the lowest cost saving of USD 0.023/m2. However, PCM installations in Jaipur’s climatic condition was deemed economically infeasible with lowest payback of 181 years.

Taking benefits of using PCMs in buildings to meet energy efficiency criteria in net zero by 2050

Considering the share of 40% and 35% of buildings in energy consumption as well as CO2 emissions, adding phase change materials (PCMs) is an effective technique to tackle high energy demand and considerable CO2 emissions. When PCMs are injected into the building envelopes, they improved the sensible/latent storage features of the envelopes. In this study, using numerical methods, defining first (no PCM), second (PCM without phase transition), and third building (with phase transition), the importance of sensible storage feature was compared to latent one. It was found that the sensible/latent importance is dependent on the thermal resistance of the envelopes and setpoint. At setpoint 22 °C, it was found that the PCM-enhanced building consumed less power by 32.4 kWhm2. Under this condition, the share of sensible storage as well as latent storage was 54% and 46%, respectively. The reason for the lower share of latent storage was that PCM never participated in phase change about 40% of the year. To boost PCM effectiveness, it was found that the PCM installation near the uppermost layer enhanced energy-saving by 3.72 kWhm2. The presence of phase change in PCM is not always considered a positive point. In one situation, it was observed that if PCM did not undergo phase transition, it reduces energy consumption by 9.4 kWhm2, while for PCM with phase transition this value was 7.1 kWhm2. PCM was also beneficial on CO2 reduction either with phase change or without phase change. In the former, CO2 emissions declined by 34.9 kgm2, and under the latter circumstances it was 23.9 kgm2.

Performance enhancement of building energy through the combination of dynamic insulation panels and phase changing materials

The use of phase change materials (PCM), a type of heat transfer thermal storage substance, shows the opportunity to enhance the thermal inertia of these structures lacking significantly altering present construction methods. Because of the decreased indoor temperature swings and the load reduction, the usage of PCMs in buildings has the potential to deliver higher indoor temperatures for inhabitants as well as weaker export power consumption. Thermal energy storage (TES) systems based on phase change material (PCM) is identified as among the most enhanced energy techniques to improve eco-efficiency and conservation. The proposed dynamic insulating material and system (DIMS) allows for thermal resistance to be adjusted based on interior and outside variables. While it can be shown that using PCM and DIMS in facades enhances energy efficiency, there have been no previous studies that looked at the combined effect of the two technologies. Explore a unique wall design that includes a sheet of PCM made up of two levels of DIMS in this research. In most of the seasons and building orientations studied in this research, the PCM-DIMS-integrated wall saves much more energy than the DIMS-only combined barrier or the PCM-only combined walls. The PCM-DIMS-integrated walls can give a 15% to 72% decrease in yearly radiant heat then a 7% to 38% reduction in annual heat loss, based on the environment. The findings of this study highlight the necessity for scaled dynamic insulating layers for structures, as well as thermal storage devices.

Review on applications of microencapsulated phase change material in buildings for thermal storage system

Review on applications of microencapsulated phase change material in buildings for thermal storage system

Multiobjective Optimization of Cement-Based Panels Enhanced with Microencapsulated Phase Change Materials for Building Energy Applications

Thermal energy storage using phase change materials (PCMs) is a promising technology for improving the thermal performance of buildings and reducing their energy consumption. However, the effectiveness of passive PCMs in buildings depends on their optimal design regarding the building typology and typical climate conditions. Within this context, the present contribution introduces a novel multiobjective computational method to optimize the thermophysical properties of cementitious building panels enhanced with a microencapsulated PCM (MPCM). To achieve this, a parametric model for PCM-based cementitious composites is developed in EnergyPlus, considering as design variables the melting temperature of PCMs and the thickness and thermal conductivity of the panel. A multiobjective genetic algorithm is dynamically coupled with the building energy model to find the best trade-off between annual heating and cooling loads. The optimization results obtained for a case study building in Sofia (Bulgaria-EU) reveal that the annual heating and cooling loads have contradictory performances regarding the thermophysical properties studied. A thick MPCM-enhanced panel with a melting temperature of 22 °C is needed to reduce the heating loads, while a thin panel with a melting temperature of 27 °C is required to mitigate the cooling loads. Using these designs, the annual heating and cooling loads decrease by 23% and 3%, respectively. Moreover, up to 12.4% cooling load reduction is reached if the thermal conductivity of the panels is increased. Therefore, it is also concluded that the thermal conductivity of the cement-based panels can significantly influence the effectiveness of MPCMs in buildings.

Thermal storage performance of eutectic sugar alcohols applied to buildings and enhancement of crystallization

Sugar alcohols are suitable for compact and high-density building thermal energy storage systems because of the high enthalpy, low price, and non-toxicity. But most sugar alcohol materials have severe supercooling characteristic, which limits their application as phase change materials (PCMs) in thermal energy storage systems. In this study, xylitol, sorbitol, erythritol, mannitol and dulcitol were selected as PCMs. Based on the five single sugar alcohols, ten multicomponent eutectic sugar alcohols were obtained which melting temperatures is between 60 °C and 90 °C applied to buildings. The thermal parameters of sugar alcohols were tested by differential scanning calorimetry (DSC), the supercooled eutectic sugar alcohols were stimulated by means of mechanical agitation to accelerate crystallization. The crystallization after excitation was monitored by microscope, and the supercooled crystallization phenomenon of eutectic sugar alcohols was investigated by isothermal phase change tests. The results showed that only three eutectic sugar alcohols could crystallize by stirring, and the melting temperatures of three eutectic sugar alcohols are about 80 °C. After multiple repetitive experiments, three eutectic sugar alcohols still have good crystallization characteristics. The results of the research provide a reference value in practical aspects for the design and selection of phase change materials in buildings.