Phase Change Materials Panels Research Articles

Optimizing the characteristic cooling curves of PCM-integrated thermally active buildings: Experimental and numerical investigations

Phase change materials (PCMs) exploit their cyclic phase change (solidification and melting) to enable latent heat storage. While incorporating them in thermally activated building systems can potentially enhance energy savings and thermal comfort, they can introduce significant challenges to the building energy management system. This work first reports the result of small-scale side-by-side experiments on two thermally active cuboids with and without BioPCMs at different supply water and PCM melting temperatures, as well as irradiance levels. Next, a dynamic model is developed in TRNSYS v18.05 for a typical design of an office space under hot desert climate conditions. The model is then integrated into a multi-objective optimization routine using NSGA-II algorithms to identify the optimal characteristic cooling curves, melting temperatures, and PCM thicknesses that simultaneously minimize energy consumption and maximize the percentage of comfortable hours. The experimental observations of the PCM-integrated cuboid highlighted energy savings between 80.45 and 84.56 %, compared to the reference cuboid, at nearly the same levels of indoor temperatures. The PCM panels reduced the cooling capacity of the radiant floor but also dampened air temperature variations by up to 83.17 %. Besides, higher solar irradiance levels, encountered in desert areas, were found to enhance the cooling capacity by up to 46.8 %. The Pareto solutions highlighted the possibility of achieving acceptable unmet hours of 3.16 % using PCMs and without the need for an assisting air system, compared to 14.1 % without PCMs. Besides, at the same unmet hours of the reference system, the PCMs reduced the total energy consumption and the peak cooling power by 9.75 and 41.2 %, which translates into substantial operation and capital investments, respectively. Moreover, the study demonstrated by example the importance of calibrating the commonly used cooling curves of thermally active buildings when planning for PCM integration.

Bamboo-encapsulated bio-based PCM panel as thermal stabiliser for glamping in a highland area of Indonesia

Glamping has become an alternative to camping with a unique nature experience. However, maintaining the temperature and humidity for glamping tents in highland areas remains challenging. Thermal conditions inside a tent fluctuate more drastically than outdoors, affected by the outdoor conditions, leading to significantly higher temperatures inside the tent during daytime and lower temperatures during nighttime. This study investigates the performance of bamboo-encapsulated bio-based phase change materials (PCM) panels as thermal stabilisers inside glamping tents in highlands. For five cycles, the environmental factors were measured, including temperature and relative humidity (RH) inside glamping tents, with (Tent 1) and without PCM panels (Tent 0), and outdoors in a highland area in Indonesia. The measured temperature within the glamping tents was compared with the outdoor temperature, divided into four periods in the daytime (Periods A-D) and one in the nighttime (Period E). Additionally, response surface methodology was performed to understand the response of various factors influencing the performance of PCM panels. This study demonstrates that PCM panels substantially improve temperature control in glamping tents. During the daytime, bio-based PCM panels effectively maintained the indoor temperatures of Tent 1 up to 3.99 °C colder than Tent 0. In conclusion, this study highlights the significant impact of PCM panels in stabilising the temperature inside the glamping tent, which also affects RH.

Numerical model for determining the effective heat capacity of macroencapsulated PCM for building applications

This paper presents a finite difference model of macroencapsulated PCM panels coupled with the genetic algorithm for the determination of effective heat capacity of whole panels via inverse method. This provides an accurate characterization of the thermal properties of macroencapsulated PCMs for building envelope applications. A novel definition of the effective heat capacity is proposed based on the superimposition of two Gaussian curves, applicable to any PCM whose phase transition is characterized by a single peak. Three PCMs were tested, subjected to temperature variation rates typically experienced in building envelopes: 0.5 °C/h and 1 °C/h. Surface temperature and heat flux were measured and used in the inverse method procedure. The developed model is accurate, as numerical results greatly agree with the experiments: the root mean square difference between the experimental and numerical heat fluxes ranged between 0.543 and 1.246 W/m2. Significant differences in the effective heat capacity were found between the whole macrocapsule and small quantities of PCM (specified in the datasheets). The effective heat capacity specified in the datasheets is sensibly greater than that of the whole macrocapsules determined through the inverse method: the specific heat in the solid phase was up to 107.39 % higher in the datasheet values, the specific heat in the liquid phase up to 184.04 %, and the peak effective heat capacity, between 18.28 % and 164.11 %. The same happened to the enthalpy: datasheet values were 61.24 % – 175.55 % greater than inverse method results. This proves that latent heat is overestimated if small quantities of PCM are analyzed, and not the whole panels. The scale effect was assessed by comparing two capsules with the same material, but with different quantities of PCM: 0.5 kg and 1 kg. A greater mass of PCM over the total mass of the capsule implies a different relationship between the effective heat capacity and temperature, with higher peak heat capacity. The capsule with 1 kg of PCM showed a peak effective heat capacity up to 30.65 % greater than that of the panel with 0.5 kg of PCM. Thus, adequate modeling in building applications requires characterization of whole macroencapsulated PCMs. The determination of the relationship between temperature and effective heat capacity of macroencapsulated PCMs presented in this work could easily be incorporated into other simulation software, facilitating the assessment of adaptive envelopes with PCM macrocapsules.

Hysteresis model predictions of thermal performance of hempcrete-based walls with phase change materials

Phase Change Materials (PCMs) can improve the energy performance of buildings by storing and releasing large amounts of thermal energy with low or no temperature variation. However, they require optimal integration to be fully effective. While numerical analysis can assist the successful integration of PCMs into building envelopes, only a few tools can simulate the hysteresis effect, and all of them introduce simplifications that might hinder prediction accuracy, especially in case of interrupted phase change. This work addresses these limitations by proposing a novel algorithm for realistic hysteresis modelling by introducing a new path for changing the liquid fraction during the partial phase change process to enable the phase change curve transition without assuming that the liquid fraction is constant. The new model was validated against experimental results and compared to three widely used PCM hysteresis methods: Track, Switch, and Scale. This study is also the first to compare the effect of several hysteresis models applied to two different PCM integration methods into hempcrete wall assemblies based on microencapsulation and macroencapsulation techniques. The results of the different hysteresis models vary significantly depending on the PCM integration technique, the observed design parameter, the schedule heating setpoints, and the PCM percentage in the wall. When applied to a hempcrete wall with a PCM panel, the models showed a significantly higher sensitivity in the three performance parameters (heating energy consumption, liquid fraction, and inner temperature) than when applied to a hempcrete wall infused with the microencapsulated PCM.

Thermal and energy performance evaluation of a full-scale test cabin equipped with PCM embedded radiant chilled ceiling

The escalating global demand for space cooling has led to the emergence of new cooling technologies, including the phase change material embedded radiant chilled ceiling (PCM-RCC) system. This technology improves energy efficiency and indoor environmental quality, while also offering demand-side flexibility. The present study experimentally evaluates the thermal efficiency and energy performance of a PCM-RCC system in a full-scale test cabin equipped with PCM panels. Here, the transient thermal behaviour of PCM ceiling panels besides the cooling energy delivered during charging-discharging cycles are examined. The indoor thermal comfort and peak electricity demand reduction enabled by the present PCM-RCC are also discussed. The results reveal that chilled water circulation for 4–5 h overnight was sufficient to fully recharge the PCM panels. Over 80% of the occupancy time was classified as “Class B″ thermal comfort according to ISO 7730. The system's daily electricity usage was mostly concentrated during off-peak hours, accounting for ∼70% of the total usage. While the controlling schedule used in this study responded to the transient thermal behaviour of the indoor space and PCM ceiling panels, a more dynamic, predictive schedule is necessary to improve the system's overall efficiency and further enhance indoor thermal comfort in response to the changing environmental conditions.

Investigating the Influence of Thermal Conductivity and Thermal Storage of Lightweight Concrete Panels on the Energy and Thermal Comfort in Residential Buildings

Phase change materials (PCM) are integrated into lightweight concrete (LWC) panels to increase their thermal mass. However, the integration of PCM into LWC also increases the thermal conductivity of the panels, which may have a negative impact. This study investigated the impact of thermal resistance and storage of LWC panels on thermal comfort and energy use in buildings. Six different LWC panels with varying levels of thermal conductivity and storage were developed using various combinations lightweight aggregates and PCM. The experimentally measured properties were used in building simulation software EnergyPlus V9.3 to calculate overheating and building energy consumption for each panel. The result showed that thermal mass influences severe discomfort hours more than thermal resistance. However, the level of influence depends on the position of the panels compared to the insulation layer. The presence of an insulation layer reduced the energy savings rate. The cooling energy consumption was more influenced by the thermal mass, whereas the heating was more influenced by the resistance of the wall. Overall, the LWC panel with the highest thermal mass was the best to reduce severe discomfort hours and energy consumption despite having the highest thermal conductivity. The outcome of this study can help to design an external building envelope with PCM panel as per user requirements, which could be to reduce overheating or cooling only, heating only, or both cooling and heating.

Preparation and Characteristics of Na2HPO4·12H2O-K2HPO4·3H2O/SiO2 Composite Phase Change Materials for Thermal Energy Storage.

In this paper, a series of eutectic hydrated salts was obtained by mixing Na2HPO4·12H2O (DHPD) with K2HPO4·3H2O (DHPT) in different proportions. With the increase in the content of DHPT, the phase transition temperature and melting enthalpy of eutectic hydrated salts decreased gradually. Moreover, the addition of appropriate deionized water improved the thermal properties of eutectic hydrated salts. Colloidal silicon dioxide (SiO2) was selected as the support carrier to adsorb eutectic hydrated salts, and the maximum content of eutectic hydrated salts in composite PCMs was 70%. When the content of the nucleating agent (Na2SiO3·9H2O) was 5%, the supercooling degree of composite PCMs was reduced to the minimum of 1.2 °C. The SEM and FT-IR test results showed that SiO2 and eutectic hydrated salts were successfully combined, and no new substances were formed. When the content of DHPT was 3%, the phase transition temperature and melting enthalpy of composite PCMs were 26.5 °C and 145.3 J/g, respectively. The results of thermogravimetric analysis and heating-cooling cycling test proved that composite PCMs had good thermal reliability and stability. The application performance of composite PCMs in prefabricated temporary houses was investigated numerically. The results indicated that PCM panels greatly increased the Grade I thermal comfort hours and reduced energy consumption. Overall, the composite PCM has great development potential building energy conservation.

Study on the influence of thermo-physical parameters of phase change material panel on the indoor thermal environment of passive solar buildings in Tibet

In this study, an unsteady heat transport numerical model of phase change material (PCM) panel under indoor-outdoor dual thermal disturbance conditions was development by using the apparent heat capacity method, which was employed to evaluate the effect of thermal performance parameters of PCM on the heat storage and temperature regulation capability of PCM panel. Then, a single-space passive solar building located in Tibet was used as a basic building model to study the influence of thermo-physical parameters, such as phase change temperature, thickness and position of PCM panel in composite wall on indoor thermal environment. Meanwhile, the indoor discomfort degree hours and heating energy consumption of the passive solar building with composite wall containing PCM panel were quantitatively analyzed, and the dynamic payback period of PCM investment in Tibet was calculated for economic analysis. The results indicated that the phase transition temperature, thickness and position of PCM panel have a significant impact on its heat storage and temperature regulation capability, and the composite wall containing PCM panel with reasonable thermo-physical parameters could obviously damp indoor air temperature fluctuation and save the building heating energy consumption. Compared with the basic building, applying a 30 mm thickness PCM panel with phase transition temperature of 18 °C on the interior side of the composite wall could reduce indoor discomfort degree hours in studied period (Dec. 20 to Dec. 24) by 74.9% and reduce heating energy consumption in the whole heating period (Dec. 01 to Mar. 01) by 20.76%, respectively. Furthermore, the economic analysis results show that the application of PCM panels in passive solar buildings in Tibet has high economic value, and the dynamic payback period of PCM investment in Tibet with 3% discount rate is 41.29 years, which is lower than the usual service life of a building.

Experimental investigation of the impact of design and control parameters of water-based active phase change materials system on thermal energy storage

Phase Change Materials (PCM) has the potential to reduce building energy consumption and emissions, which is essential to combat the climate change threat. Theoretically, PCMs are reported to achieve massive energy savings in buildings. However, in real-life scenarios, the results vary vastly from the theoretical or experimental results due to many factors and parameters that need to be taken into consideration. This study is an extension of a previous study of the present authors where an active PCM system installed in a multi-storey building was reported to be inefficient and not achieving the desired savings. To understand the reasons, this study experimentally investigated the influence of inlet water temperatures and flowrates on the melting, solidification and energy storage of active PCM system using a small-scale model of the real system. The results showed that the PCM solidification rate strongly depends on the inlet water temperature and is less sensitive to the inlet water flow rates. The lower the inlet water temperature, the shorter the time required to solidify the PCM. However, at higher flow rates, PCM melts and solidifies more uniformly compared to lower flow rates. The optimum inlet water temperature to solidify all panels inside the PCM tank also depends on the length of the PCM tank. The longer the PCM tank, the lower should be the inlet water temperature to ensure complete solidification of PCM panels towards the end. For the studied system, 8 °C inlet water temperature was recommended to ensure complete solidification of PCM panels inside the tank. Moreover, the PCM was never 100% solidified or melted, which means a loss factor should be considered when a PCM tank is designed. The findings of this study will assist the designers/engineers in designing an active PCM system that can achieve the desired savings in real life and minimize the energy performance gap.

Numerical study on thermal comfort and energy-saving potential of a prefabricated temporary house integrated with composite phase change materials

The prefabricated temporary house (PTH) has been widely used in various scenarios because of its convenience and environmental protection. However, PTHs are usually lightweight buildings with weak thermal inertia, resulting in poor indoor thermal comfort. Numerical research was conducted on the potential of phase change materials (PCMs) as a passive alternative to enhance the performance of the PTH throughout the year in this study. The influences of some critical factors such as thickness, phase change temperature, ventilation, building orientation, and climatic region on the thermal characteristics of PTHs were evaluated. The thermal comfort hours and energy consumption were employed as indicators to quantify the influence of PCMs on the dynamic thermal performance of PTHs. The numerical results indicated that the thickness had different effects on the PTH in different climate regions. When the total thickness of the wall was constant, I-level thermal comfort hours of the PCM rooms were higher than those of the reference room. For the Beijing area, when the wall was composed of a 100 mm insulation board, the indoor I-level thermal comfort hours were 803 h, while when the wall was composed of 90 mm insulation boards and 10 mm PCM panels, the indoor I-level thermal comfort hours increased to 1511 h. Moreover, it was worth noting that the optimal PCMs for different building orientations were basically the same, but the optimal PCMs for the PTH with and without air conditioning were different. Ventilation significantly increased thermal comfort hours and reduced energy consumption for the PTH in Guangzhou, while a larger ventilation rate would reduce the thermal comfort hours of the PTH in Kunming. In general, the numerical results supported and highlighted the potential of integrating PCM in the PTH to enhance living comfort and reduce energy consumption.

Experimental Study of PCM Cooling Storage System for Hot Climates

In this work, the application of a PCM cooling system for hot climate applications is investigated. A novel design proposes the utilization of PCM panels to reduce the energy demand on an air-cooling system by absorbing a proportion of the thermal load. The system not only contemplates the application of the S27 PCM panels for indoor cooling but also considers a PCM-TES box to enhance the cooling performance. The experimental evaluation focused on two operating schedules, during daytime the environmental temperature was considered at 30°C, and at night-time, the temperature was reduced to 25°C. The results found an indoor average temperature difference of 1.8°C with the addition of the PCM panels. In terms of energy savings, the chiller energy consumption was positively impacted as the PCM reduced the operational time.

Performance improvement of a PCM cold box by two bilayers configuration

A method to increase the storage time of frozen materials in a PCM cold box maintained at a sub-zero temperature has been investigated in this paper. The configuration of a single Phase Change Material (PCM) pack surrounding the payload and subsequently surrounded by an insulation layer is termed as a bilayer configuration. Our study shows that by changing the configuration into two bilayers, which is a series of PCM and insulation pairs, a significant advantage is gained in terms of the total time for which the payload stays at the desired frozen temperature. A parametric thermodynamic model is developed to calculate melting time of the PCM in a single and a two bilayer box configuration having same volume of the PCM and insulation materials. Rather counterintuitive, the model revealed that the optimum design is when the PCM mass is asymmetrically distributed in a two bilayer configuration. Using the properties of a eutectic PCM (melting point of −49.8 °C) and vacuum insulation panels, a storage time increase of more than 30% is achieved when the inner PCM mass is 10% of the total PCM mass. The ambient temperature considered in this example is 20 °C. Furthermore, it is shown that the storage time increases when the temperature difference between the ambient and the PCM melting increases for a two bilayer configuration.

Lessons learned from PCM embedded radiant chilled ceiling experiments in Melbourne

Buildings are responsible for over a third of energy consumption worldwide, particularly due to the increasing demand for air-conditioners in response to the more extreme heat around the globe. It is imperative to move towards more energy-efficient space cooling alternatives. The integration of phase change material (PCM) with radiant chilled ceilings (RCC) is a promising technology due to its benefits regarding energy efficiency and indoor environmental quality. This article presents a field study conducted on a newly-developed PCM embedded radiant chilled ceiling (PCM-RCC) installed in a stand-alone cabin located in Melbourne. The study evaluates the thermal and energy performance of the system through investigations of the transient thermal behaviour of PCM panels in charging-discharging cycles, the indoor comfort conditions, and the electricity peak demand. It was observed that the proposed PCM-RCC can provide satisfactory comfort conditions and contribute to load shifting if a refined operating strategy is applied. The efficiency of PCM recharge overnight depends on several factors that need to be carefully considered in design. The challenges related to the implementation of optimal operating dynamic schedules in response to the thermal behaviour of PCM-RCC, and accurate weather forecasting should be addressed to realise the full potential of this technology.

In-duct phase change material-based energy storage to enhance building demand flexibility

This paper presents a novel energy storage solution by incorporating phase change material (PCM) panels in supply ducts to increase a building’s thermal storage capacity and demand flexibility. During off-peak hours, the system runs at a supply air temperature (SAT) below the PCM solidification point to charge the storage unit with “cooling” energy. During on-peak hours, a higher SAT is utilized so that the stored “cooling” energy can be discharged into the supply-air as a means to reduce the peak air-conditioning power usage. To evaluate the potentials of peak demand reduction and utility cost savings, a numerical model for a PCM panel prototype and its heat exchange with the air flow in the duct was developed and calibrated using experimental data. Whole building energy simulations were conducted in a co-simulation environment that has integrated the developed PCM model, EnergyPlus Department of Energy (DOE) prototypical model for a medium office building and a calibrated model for variable-speed direct-expansion cooling systems. The simulations covered five cities in different U.S. climate zones over a three-month cooling season and used actual time-of-use (TOU) rate schedules offered by the local electric utility companies. The simulation results have shown the PCM storage could reduce the on-peak energy consumption by 23–32% and the seasonal cooling electricity cost by up to 16%, with a simple rule-based control strategy. A simple payback analysis resulted in payback periods from 7.5 to 27 cooling months.

Dynamic melting of encapsulated PCM in various geometries driven by natural convection of surrounding air: A modelling-based parametric study

Encapsulated phase change material (PCM) has a great potential to reduce the fluctuation of indoor air temperature and subsequent building energy consumption through ceiling applications in air-conditioning systems. However, the effects of capsule geometry on the dynamic melting performance remain unknown when the melting is driven by natural convection. In this work, we modelled the melting behavior of PCM encapsulated in six different capsule shapes subject to natural convection of surrounding air, which was validated by our measurement results. The model considers the conjugate heat transfer through the surrounding air, capsule shell and PCM, enabling the prediction of a three-stage dynamic melting process. The melting process of the encapsulated PCM were further studied for varying inclination angles (with respect to the vertical axis), temperature differences (between the surrounding air and PCM), and capsule sizes. The results show that the capsule geometry plays a dramatic role in the time of phase change. At the ambient temperature of 22°C, the short cylindrical capsule with a horizontal axis takes the longest time to complete phase change (162 min), whilst the pyramidal capsule with a horizontal base takes the shortest time (120 min). We also quantified the heat transfer between capsules and surrounding air for varying temperature difference and capsule size, and found that the pyramidal and tetrahedral capsules with a horizontal base melt faster than capsules of other shapes due to the higher heat transfer rate caused by larger surface area. For cases with a medium capsule size and low temperature difference, early termination of melting at 80% liquid fraction is recommended since more than 30% of melting time can be saved with only 20% reduction in cold storage capacity. This work provides a validated model that is able to predict the dynamic melting process of PCM of different geometries, which will enable informed design of PCM panels for improving thermal management and comfort in buildings.

Experimental investigations on the performance of a rectangular thermal energy storage unit for poor solar thermal heating

A novel rectangular energy storage unit (RTESU) is proposed to effectively harvest low-radiant solar energy in poor solar areas for the application of preheating cold outdoor air. The RTESU consists of tube bundles to charge phase change material (PCM), paraffin wax PCM panels and air channels to discharge heat to cold outdoor air. Experiments on the charging and discharging processes with heat transfer fluid (HTF) temperature (varying from 28 to 36℃) and flow rate (varying from 0.96 to 2.04 m3/h) are performed to investigate the thermal performance of the device for poor solar areas. PCM temperature variations, heat transfer characteristics, heating capacity, and melting and solidification dynamics are analyzed. The results reveal that solar energy can be harvested and stored in PCM through melting process even under extremely poor solar radiation (about 138.68 W/m2) within 3.6 h. During the charging process, the natural convection plays a dominant role, while conduction is dominating throughout the discharging process. Further analysis of the thermal performance of discharging process shows that the heat extraction effectiveness can be improved as the air inlet temperature decreases. The highest heat extraction effectiveness can approach 100% in 10.2 h when the air inlet temperature ranges from 11.5 to 13 °C.

Design and control of radiant ceiling panels incorporating phase change materials for cooling applications

Experimental and numerical studies have demonstrated that thermally activated building systems (TABS) may lead to significant energy savings. However, TABS are generally incorporated into the building during the construction phase, limiting their adoption to new buildings. To encourage the application of TABS during building refurbishments, the authors have developed a radiant ceiling panel (RCP) with macroencapsulated phase change materials (PCM). This study aims to provide the criteria to design, size, and control the newly proposed RCP-PCM system. A simplified method to size and design the RCP-PCM system for cooling applications is developed from a set of parametric dynamic simulations. At first, the thermal storage properties of the macro-encapsulated PCM were determined using the standard ASTM C1784-20. The obtained properties were then used in a whole-building simulation model validated using measurements in a small test chamber that replicates the conditions of an actual test room. The PCM panel thickness of 0.015 m and a supply water temperature of 15 ℃ showed the best results in terms of thermal comfort and effective thermal energy storage capacity. The implementation of the simplified method in a case study showed that the RCP-PCM system maintained room conditions within the specified thermal comfort range (−0.5 < PMV < 0.5) for more than 90% of the occupied periods in all of the evaluated cooling-dominated climates. Moreover, yearly-round, the PMV values never reached values higher than 0.8 or lower than −0.6, confirming the effectiveness of the proposed method for designing a RCP-PCM system. The results show that energy savings of 22% could be obtained in a very hot and humid climate using an RCP-PCM system instead of a conventional all-air system. In conclusions, this paper offers a new system to promote energy flexibility and Demand-Side Management (DSM) strategies to modulate the energy demands in retrofitted buildings.

The influence of macro-encapsulated PCM panel’s geometry on heat transfer in a ceiling application

ABSTRACT One of the deficiencies of using Phase Change Materials (PCMs) is the low conductivity, therefore, increasing the heat transfer from and to the PCM remains a challenge. The exposed surface area of the container can play a major role in the amount of heat transfer. Furthermore, building energy simulation always considers surfaces as slabs without shapes consideration. This paper aims to broaden the current knowledge of the relation between the exposed surface area of a macro-encapsulated PCM panel and the heat transfer with the environment. For this study, coconut oil was considered as PCM encapsulated in a thin plastic container, represents an aesthetic PCM panel attached to the ceiling. The results showed that an increase of 50% in the exposed surface area to volume ratio could lead to a 20% reduction of the time required to completely melt the PCM. Results also showed that the convective heat transfer coefficient is proportional to the exposed area to volume ratio, and for that an equivalent heat transfer coefficient is proposed to be used in building simulation tools when dealing with non-slab geometry.

Judicious method of integrating phase change materials into a building envelope under Saharan climate

Phase change materials (PCMs) have been extensively used for thermal storage systems in buildings. To enhance the building's thermal and energy performance, PCMs can be embedded into envelope systems to reduce the cooling and heating demand. A PCM's melting temperature close to the thermal comfort range (20°C-26°C) can potentially be an attractive solution. In this work, the thermal and energy performance of a building in Saharan climate, specifically Ghardaïa in Algeria, was modeled using the TRNSYS-18 simulation package. A newly developed module (Type-285) was compiled for this version to evaluate different PCMs integration approaches in building envelope. Integration techniques have been evaluated based on three performance indicators, namely, monthly and annual energy savings, mean air temperature, and the daily average temperature fluctuation. When considering the conventional PCMs integration within the building envelope, a reduction of 36.4% in annual energy consumption was achieved. The study indicated that when PCMs are carefully integrated based on orientations and seasons, a reduction of 50.71% in annual energy consumption is possible, an additional 14.34% to the conventional PCMs integration. In addition, PCMs provided an enhanced thermal performance and a significant reduction in indoor temperatures that ranged between 2.36°C to 4°C. The study proposes an improved PCMs integration approach which can be possibly implemented if movable PCMs panels are used instead of the conventional static PCMs panels.

Experimental Study of the Use of Phase Change Materials as Cooling Media on Photovoltaic Panels

Building Integrated Photovoltaics (BIPV) is a combination of electrical technology from photovoltaic solar panels (PV) with building construction. The PV panel was mounted onto the frames attached to the building's main outer wall. When solar radiation energy comes into contact on the PV surface, some part is reflected in the surroundings while mostly absorbed in the PV panel. The energy absorbed is converted into electricity while the rest dissipates into thermal energy, which increases the surface temperature of PV. The increases in the panels' surface temperature negatively impact the electrical output and PV panels' long-term reliability. One of them is the use of phase change materials (PCM) as heat storage materials. This research also emphasizes the use of beeswax as a material for storing heat energy. Using the T-History method by fusing beeswax, show that the temperature range between 49,40 to 57.15 oC with latent enthalpy 151.65 kJ/kg. In this research, we tested the use of PCM as a heat storage material for PV panels. Two types of containers to accommodate PCM are used, triangular containers and semicircular containers. From the test results, it was found that beeswax can function well as a heat storage so that the surface temperature of the PV + PCM panel is lower than that of standard PV. So that the voltage generated is higher than standard PV panels.