Integration Of Phase Change Materials Research Articles

Design of MoS2/MMT bi-layered aerogels integrated with phase change materials for sustained and efficient solar desalination

Solar desalination is a promising technology which can produce drinkable water from seawater or wastewater driven by solar energy. However, the intermittency of the sun restricts the evaporation rate and freshwater output yield. Here, in order to promote solar energy utilization efficiency and freshwater yield, phase change materials used as solar thermal energy storing materials are introduced into the solar evaporators. The designed solar evaporator has a double layer aerogel structure, in which the bottom layer is constructed by montmorillonite (MMT) aerogel with a function of water supply and thermal insulation. At the same time, the upper layer aerogel, which are constructed by MoS2 and paraffin@SiO2 phase change microcapsules, plays the role of solar energy harvesting, storage and solar steam generation. In this strategy, the phase change microcapsules with a latent heat of 177.85 J/g enables the solar evaporator to store solar thermal energy during illumination, and to release heat for continuous seawater desalination when there is no sunlight. Results show that MoS2/MMT solar evaporator achieves a water evaporation rate of 1.32 kg·m−2·h−1 and an evaporation efficiency of 86.22 % at a light intensity of 1 kW·m−2. When there is no sunlight, the evaporation rate and evaporation efficiency are still as high as 0.71 kg·m−2·h−1 and 44.36 % even after 20 min running, which greatly promotes the solar energy utilization efficiency and freshwater yield. In addition, the solar evaporator can produce high-quality fresh water with 99.9 % salt ions removal. Through the integration of phase change materials, the solar evaporator enables sustained and efficient solar desalination regardless of solar intermittency, resulting to great promising future in the large-scale freshwater production.

Short recent summary review on evolving phase change material encapsulation techniques for building applications

As the world deviates towards sustainability in buildings due to massive increase in energy demand, the effective integration of Phase Change Material (PCM) in buildings gained substantial attention. The capability of PCM in enhancing the thermal performance of buildings relies heavily on the encapsulation technique used as it is in direct link with enhancement techniques required for upgrading thermo-physical, chemical and environmental PCM properties. The current study reviews shortly recent literature involving PCM integration in buildings and highlights different encapsulation techniques used for their proper active and passive incorporation. It also summarizes recent methodologies of properties enhancements prior to encapsulation. Preliminary results reflect the importance of proper encapsulation using the five distinct techniques: direct mixing, imbibing, shape-stabilization, macro-encapsulation and micro-encapsulation. Commercialization of macro-encapsulated PCMs is dominant over other techniques, where micro/nano-encapsulation technique is still limited and requires further study being the most promising.

Energy, environmental, and economic analysis of different buildings envelope integrated with phase change materials in different climates

Several technologies were been developed to store the solar energy for different applications especially in the construction sector. Integrating phase change materials (PCM) into building is one of the effective solutions for energy efficiency.This paper aims to evaluate the optimal envelope type and climatic zone able to improve the performance of buildings using PCM. A numerical simulation was conducted using the difference finite method by Energy plus, in three climates of North Africa; Mediterranean, arid and sub-arid climate, concerning four different building envelopes (brick, concrete block, reinforced concrete and earth) to analyze the energy, economic and environmental impact.The maximum values of energy saving rate is found in the arid and sub-arid climate, with the highest value of 10.5 % for earth envelope, and the lowest value of 2.57 % for concrete block envelope in Mediterranean climate. The use of PCM is more efficient for cooling in arid climate for the different considered envelopes with a maximum of cooling energy reduction of 7.3%, and its use in the sub-arid climate and the Mediterranean one is more efficient for heating with a maximum value of 10.7% in the earth envelope.The environmental and economic analysis shows that the use of PCM in optimal conditions can reduce 10 % of energy cost and 707 kg/year of CO2 emissions. Furthermore the payback period obtained varied between 7 and 43 years with an average of 23 years.Conclusively, the use of PCM for thermal energy storage in buildings still a good solution for energy performance.

Energy performance enhancement of residential buildings in Pakistan by integrating phase change materials in building envelopes

The residential sector of Pakistan is a prime consumer of energy. With the fossil fuel-dependent energy generation setup and an increasing energy supply–demand gap, Pakistan is headed towards an energy fiasco. Therefore, drastic measures are required to enhance the energy efficiency of residential buildings in Pakistan. The current study is aimed to numerically investigate the energy performance enhancement of residential buildings by integrating Phase Change Materials (PCM) in the building envelopes of five major cities of Pakistan having different climates. The numerical computations are carried out in open-source building-simulation software, EnergyPlus. Initially, fifteen suitable PCMs are evaluated for a single-room base case house. CrodaTherm24 having a melting temperature of 24 °C with a thickness of 40 mm is found to be the optimum PCM choice when it is placed on the inner sides of building envelopes. It is then integrated into typical single-Storey and two-Storey multi-zone residential buildings. For a single-Storey building, the average monthly energy saving of 44.9% is achieved in Islamabad, 35% in Karachi, 32% in Lahore, 35% in Peshawar, and 49.6% in Quetta while for two-Storey buildings the average monthly energy saving of 12%, 21.4%, 15.5%, 12.9%, and 13.5% are achieved, respectively. The economic feasibility of implementing PCM in building envelopes is evaluated through static and dynamic payback period calculations. The usage of PCM for energy efficiency enhancements of residential buildings is found to be economically feasible for Lahore, Karachi, and Peshawar whereas, it is unsuitable for Islamabad and Quetta.

Effectiveness of phase change material in improving the summer thermal performance of an office building under future climate conditions: An investigation study for the Moroccan Mediterranean climate zone

The rise in global temperature due to the climate change phenomenon would increase the severity of summer season in the future. The integration of phase change materials (PCM) into the building envelope has been considered as one of the most promising measures to improve the thermal performance of buildings. This paper aims at investigating the effectiveness of the PCM in improving summer thermal performance of buildings under the climate conditions of the next three decades. The moderate scenario RCP4.5 of the Intergovernmental Panel on Climate Change was used to simulate future climate conditions. The present study was conducted for two building case studies: free-running and air-conditioned office buildings located in the north of Morocco (Mediterranean climate with hot summer). The findings have disclosed that an appropriate selection of the PCM melting temperature could enhance the thermal performance by 9.87 % for the free-running building and by 20.5 % for the air-conditioned building case over the whole building lifespan (30 years). A decade-by-decade analysis showed that the effectiveness of the optimum selected PCM would slightly decline over time. The research involved an economic analysis of the air-conditioned building case study. The latter led to calculating the maximum allowable cost of the PCM installation to achieve a payback period within the lifespan of the building. The findings of the present work can be used as guidelines to design office buildings integrated with PCM in the Mediterranean region.

Design and Performance Evaluation of Thermoelectric Cooling System Integrated with PCM (Phase Change Material)

A thermoelectric system integrated with PCM (Phase Change material) for cooling vaccines has been introduced, thermal management techniques (i) using high performance heat sink on sides(hot, cold) of module (ii) integration of PCM (ice) on cold side were analysed. Experimental results infers that, by adopting water cooled heat sinks at hot side and air cooling at cold side of module, a COP of 0.124 with minimum cooling temperature (Tc) of 6°C (at 130 minutes) is attained by the system. Performance simulations were carried with CFD (computational fluid dynamics) model of system for different heat sink configurations (with or without integration of PCM). Simulation results shows that, (i) in the absence of PCM, a COP of 0.261 and 0.245 is achieved by the system for heat sink configuration of fin and fan on both sides, fin and fan on hot side and fan on cold side respectively, (ii) COP is improved to 0.406 with integration of PCM and is 55.55% higher, considering the same heat sink configuration (fin and fan on both sides), with cooling temperature of 4°C.

Hierarchically nanostructured Co(OH)2/MXene/SiO2/n-docosane phase-change composites for enhancement of supercapacitor performance under in-situ thermal management

Electrochemical energy-storage devices usually suffer from performance deterioration at high operating temperatures due to exothermic redox reactions during the cyclic charge–discharge process. Aiming at addressing this crucial issue, we have developed a novel type of thermoregulatory electrode material based on the hierarchically nanostructured Co(OH)2/MXene/SiO2/n-docosane phase-change composite for enhancing electrochemical energy-storage performance of supercapacitors through in-situ thermal management. The resultant composite shows a regular spherical morphology and a layer-by-layer core-shell microstructure for the phase-change microcapsules anchored on MXene nanosheets, together with a well-defined nanostructured Co(OH)2 layer deposited on the surfaces of the microcapsules and nanosheets. Through a multilevel integration of phase change material (PCM) and electroactive materials in an electrode material, the microenvironmental temperature surrounding the working electrode can be regulated effectively, buffering the heat impact to supercapacitors at high temperature. The phase-change composite achieved a satisfactory latent heat capacity of over 130 J/g together with good thermal cycling stability for long-term use in thermal management of supercapacitors. Compared to conventional electrode material without a PCM, the thermoregulatory electrode material developed in the current work exhibits an increase in specific capacitance by 6.6% at 45 °C and in capacitance retention by 10.8% after 3000 charge-discharge cycles at 45 °C, suggesting better electrochemical energy storage performance and higher charge-discharge cycling stability at high operating temperature thanks to its in-situ thermal management effectiveness. This study provides a promising approach to developing high-performance electrode materials for supercapacitor application over a broad temperature range.

Investigation of Thermal Performance of 3D Printing Integrated Phase Change Materials in Building Structure

This paper aims to create an experimental building structure using 3D printing technology to reduce the interior temperature. Because of its sensitivity to high temperatures, particularly its low heat deflection temperature, and susceptibility to deterioration over time, the Polylactic acid (PLA) material has been preferred to print the layer. In this model, an effort was made to decrease the building's overall cooling load, which may result in a higher amount of ordinary power being required. For the study, a new model of the intended wall was developed and tested. The studies were carried out in two modes: the first without any PCM in the wall, and the second with an additional new model of PCM 3D-printing layer within the wall. The test results demonstrated that the PCM 3D-printing layer inside the wall building lowered the temperature of the outer wall surface, the inner wall surface, and subsequently the building temperature of the indoor area to a huge amount. The achievements are in the percentage peak temperature reduction of 9.8% for the wall's outer surface, 22.6% of the inner wall surface, and 13.4% of the room temperature. With the help of the PCM 3D-printing layer, the peak indoor temperature was decreased by 5℃.

Integrating phase change material in building envelopes combined with the earth-to-air heat exchanger for indoor thermal environment regulation

To utilize the combined effects of earth-to-air heat exchanger (EAHE) and phase change material (PCM) in indoor thermal environment regulation during summer, this study proposes a combination mode, i.e., EAHE–PCM. In this method, EAHE continuously provides cool air to indoor spaces. PCM integrated into building envelopes stores excess cold provided by EAHE at night and transfers it indoors across time. We performed two full-scale comparative experiments (EAHE–PCM combined operation mode and PCM alone operation mode) on typical summer days in hot-summer and cold-winter regions. The results showed that the maximum reduction in the EAHE outlet air temperature and moisture content reached 21.6 °C and 4.55 g/kg, respectively, inducing an average cooling capacity of approximately 1186.5 W. The use of EAHE decreased the time-averaged PCM internal temperature by 6.0 °C in 24 h compared to the PCM alone operation mode, thereby activating the phase change process of PCM between 19:54 and 9:45. Therefore, PCM can store excess cold provided by the EAHE via latent heat and transfer it to indoor air through the melting process, resulting in a 157 min lag in the PCM internal temperature rise. When the ambient air temperature varied between 26.3 and 45.2 °C, the EAHE–PCM combined operation mode decreased the time-averaged indoor air temperature by 6.6 °C compared to the PCM operation alone, which helped maintain the indoor air temperature within the comfort temperature range of 22–28 °C for 73% in 24 h, with a peak temperature of 30.6 °C.

Integration of phase change materials in improving the performance of heating, cooling, and clean energy storage systems: An overview

Phase change materials (PCMs) have garnered significant attention as low-cost thermal energy storage systems that efficiently capture and store solar energy. Recent review works have largely focused only on thermal conductivity enhancement techniques, and/or applications of PCMs, while others have mainly discussed the performance enhancement of either heating, cooling, or clean energy storage systems integrating with PCMs. However, not enough studies recently reviewed all of these techniques/systems comprehensively to provide insights into them. This paper thus comprehensively reviews the integration of PCMs as an enhancement to most types of heating, cooling, and clean energy storage system performance, and the techniques to enhance thermal conductivity. The integration of PCMs with these systems has shown promising performance. For instance, an improvement of 13.5% is found in the efficiency of photovoltaic (PV) system when it is integrated with PCM/Al2O3 nanoparticles. In addition, the solar air heater's daily energy efficiency reaches 17% on its own, but when combined with PCM, it reaches 33%. However, the major drawback of using PCM–TES (thermal energy storage) for cooling is that PCM does not entirely solidify at night. The literature also shows that the issues related to PCMs' low thermal conductivity, phase separation, and subcooling/supercooling, their poor compatibility with other materials, and the environmental hazards they pose hinder their application on a large scale. It is necessary to implement international standards for assessing the thermophysical properties of PCMs and compile data to better facilitate the utilization of PCMs by end-users.

Incorporating phase change materials into glazing units for building applications: Current progress and challenges

• Both light and heat transfer characteristics of glazing systems should be considered. • Usage of phase change materials helps reducing energy loss through glazing systems. • Measurement and numerical models are inadequate to study photo-thermal transmission. • More research on effect of phase change materials on acoustic performance is needed. • Database lacks optical properties of solid and molten nano-phase change materials. Building envelopes consist of transparent and non-transparent components, and pose distinct opportunities and challenges in energy conservation. Glazing envelopes, which are transparent, are mainly responsible for the lighting and ventilation of buildings, but the acoustic performance may be weakened. Since glazing envelopes suffer from the defects of high solar transmittance, poor thermal insulation, and low thermal inertia, their energy-saving technologies are significantly different from those of non-transparent envelopes. Different energy-saving technologies have been studied to improve the optical and thermal performance of glazing envelopes. However, there is a lack of a review study involving the phase transition process and the improvement of photo-thermal transmission in glazing envelopes containing phase change materials. The present work provides a comprehensive overview of research advances in optical transmittance, thermal resistance, and thermal inertia along with photo-thermal transmittance in glazing envelopes, with a special focus on the integration of phase change materials. The study reveals that measurement and numerical models are inadequate to study photo-thermal transmission. Besides, it is identified that there is a research gap in the acoustic performance of glazing systems incorporating phase change materials, and there is a lack of database on the optical properties of phase change materials containing nanoparticles.

Metal-organic framework derived magnetic phase change nanocage for fast-charging solar-thermal energy conversion

Efficient capture, conversion and storage of solar energy has been a long-term pursuit facing the green and low-carbon strategic goal. Nevertheless, fast-charging solar-thermal conversion and sustainable stable energy output are the key challenges in current solar-thermal energy storage systems. Herein, we rationally designed a sustainable stable and fast-charging solar-driven energy storage system that can simultaneously supply electricity and heat by integrating phase change materials (PCMs) and metal-organic framework (MOF) derived magnetic Co-decorated hybrid graphitic carbon and N-doped carbon (Co-GC@NC) nanocage. Benefiting from the synergistic effect between magnetic Co nanoparticles and GC@NC carbon hybrid, the resultant magnetic carbon nanocage demonstrates superior full-spectrum absorption and Co-GC@NC-based composite PCMs exhibit a high solar-thermal conversion efficiency of 90.7%. More attractively, the solar-thermal energy conversion and storage efficiency of Co-GC@NC-based composite PCMs is significantly enhanced by 115.8% due to the excellent magnetic manipulation ability of nanocage when a magnetic field was applied. Meanwhile, the designed solar-thermal energy conversion and storage system achieves a maximum output voltage of 290 mV and current of 92.6 mA. This magnetic nanocage-accelerated strategy provides constructive insights into the targeted construction of sustainable and stable fast-charging solar-driven energy storage systems.

Electrical power consumption reduction in the bitcoin mining process using phase change material

In this paper, the idea of applying phase change materials (PCMs) as a method of energy use reduction in bitcoin mining will be investigated. The possible applications discussed include the implementation of PCMs in the mining equipment itself, the integration of PCMs into the mining warehouse envelope, and the use of PCMs in air conditioning systems. These applications aim to decrease energy requirements for warehouse climate control systems by decreasing their cooling load, and by increasing the efficiency of the miners by keeping them at a cooler operating temperature. This reduction in energy usage will help reduce bitcoin’s carbon footprint produced by fossil fuels electricity production.

Performance comparative study of a concentrating photovoltaic/thermal phase change system with different heatsinks

• Performance of concentrating PV/T-PCM system with different heatsinks was compared. • Non-uniformity of PV module temperature dropped by 47%∼82% when PCM melted. • Primary energy-saving efficiency of S-type system was 8% higher than H-type. • Concentrating PV/T-PCM owned superior performance than PV-CPC and PT-CPC system. In this study, a compound parabolic concentrating photovoltaic/thermal phase change system with different heatsinks (S-type and H-type) are constructed in an open-air environment to experimentally analyze the influence on photothermal, photovoltaic and heat-electricity cogeneration performance. The non-uniform irradiance distribution at different moments is simulated with the Monte Carlo rays tracing method, and it is demonstrated to be the main cause of non-uniform temperature distribution on photovoltaic module surface. The H-type heatsink system integrating phase change material (PCM) owns better temperature regulation performance, as its photovoltaic modules temperature and non-uniformity factor are about 0.8 ℃ and 0.05 lower than those of S-type respectively when PCM begins to melt. The instantaneous electrical and thermal efficiency with H-type heatsink are 0.6% higher and 10.0% lower than those with S-type, respectively. Considering that the pump power consumption of S-type heatsink is over 3 times of H-type, the instantaneous priamry energy-saving efficiency of S-type system is 8.0% higher. Simultaneously, the maximum primary energy-saving efficiency of concentrating photovoltaic/thermal phase change system with H-type/S-type heatsink is about 7.9%/14.6% and 10.7%/17.4% higher than that of concentrating photovoltaic and solar collector system respectively, showing great potential of photovoltaic/thermal phase change system in heat-electricity cogeneration performance especially utilizing S-type heatsink. Results present advantages of the system utilizing S-type heatsink and help promote the application of heatsinks in photovoltaic/thermal phase change system.

Numerical simulation through experimental validation of latent and sensible concrete thermal energy storage system

A new type of concrete with PCM (Phase Change Material) thermal energy storage system is presented. The system, developed for industrial applications, is supposed to operate with a temperature up to 400 °C and the PCM added mixture presents enhanced thermal performances. A binary mixture of salts was used as PCMs, composed of 40% of KNO3 and 60% of NaNO3, and they were absorbed by diatomite, a porous fossil flour. A stainless-steel pipe is inserted in the centre of a concrete cylinder, the whole system is insulated. The experimental tests studied two concrete mixtures, with 5% PCM in weight and without it. The charging stage is carried out via Joule's effect and the module is then cooled with compressed air through the pipe. The two mixtures were tested under the same operating conditions. The module was numerically simulated and the results were compared with previous experimental tests to calibrate the model. Further numerical simulations were conducted to test other PCM percentages, under the same conditions as the experimental tests and with thermal oil as heat transfer fluid, to evaluate a possible working scenario. The results showed that the PCM integration into the storage system led to an impressive improvement in thermal performance. The amount of stored and released thermal energy increased with the PCM integration, coming to double its original value with the highest PCM percentage integration simulated, which corresponds to 40%.

A weather forecast-based control for the improvement of PCM enhanced radiant floors

Significant energy savings and thermal comfort improvement related to radiant floor systems may not be achieved when underfloor heating/cooling is adopted in lightweight building envelopes. Phase change materials (PCMs) are suitable candidates for providing the necessary thermal inertia with a minimum effect on the construction technology. Impacting variables like internal heat gains, weather conditions and dynamic energy price require the adoption of advanced control strategies to ensure and maximise the energy benefits of PCMs. Despite the potential of model predictive control using weather prediction data has been widely examined by the literature, there is a lack of studies experimentally analysing their implementation in PCM enhanced radiant floor systems. Within the H2020 European project IDEAS the integration of PCMs in a radiant floor system was examined by the University of Ferrara through numerical and experimental investigation. A first prototype was then installed in a small experimental building characterised by a low thermal capacity. Analysis of the monitoring data for the heating period showed that solar radiation strongly impacts on the lightweight building envelope in a short time. Without suitable control, the contribution of PCM that slowly reduced its heat flux during its transition, together with solar heat gains, resulted in an excessive increase in indoor air temperature, wasting the PCM energy saving potential. The aim of the study is the evaluation of a control strategy to improve the management of PCM enhanced radiant floor systems in relation to forthcoming weather conditions in lightweight buildings. The control routine was implemented in the corresponding dynamic energy model in TRNSYS. Results estimated achievable energy saving equal to about 4% and 8% on the heating and the cooling energy demand respectively.

Characterization of Fly Ash Cenosphere – Capric acid composite as phase change material for thermal energy storage in buildings

ABSTRACT Energy demand in buildings has been steadily increasing in the recent past. The majority of energy is used to heat and cool the building envelope to maintain a conducive thermal environment for habitation. Integration of Phase Change Materials (PCM) in buildings has improved the structure’s energy efficiency by absorbing and discharging energy as latent heat. In this work, Cenosphere–Capric Acid (CeCA) composite PCM was developed by the technique of impregnating capric acid (CA) into the hollow core of the cenosphere (Ce) under vacuum followed by sealing it with SiO2. The morphology of the prepared CeCA composite was investigated by FESEM. Mineralogical characterization by XRD suggested that the mineral structure of the CeCA composite has remained unaltered. Phase change temperature and latent heat of CeCA composite were evaluated as 27.60°C and 69.07 J/g for melting and 23.16°C and 71.30 J/g for freezing, respectively. Thermo-Gravimetric Analysis (TGA) of CeCA indicated the enhanced thermal stability of the composite. CeCA composite indicated good chemical compatibility between Ce, CA, and SiO2; hence, the composite is chemically stable, as revealed by FTIR analysis. Accelerated thermal cycling of CeCA composite indicates a relatively modest change in phase change temperature of 0.6°C for melting and 0.1°C for solidification. Further characterization by TGA and FTIR, suggested that the CeCA composite is reliable for the long term. It implies that the CeCA composite has significant potential as a PCM for thermal energy storage application in construction materials and structures.

Thermal performance investigation of energy storage based U-pipe evacuated tube solar collector: An experimental study

In this study thermal performance comparison of a custom made U-Pipe evacuated tube solar collector (ETC) vs commercially available heat pipe ETC (HPETC) was investigated experimentally. The performance comparison was performed over several days with and without thermal storage media. Results from testing without thermal storage media showed U-Pipe ETC achieved higher peak water temperatures than that of HPETC, maximum of 31 °C, resulting in 13% efficiency enhancement of U-Pipe ETC compared with HPETC. Results from testing with storage materials showed peak temperatures for fin and water tank of the U-Pipe ETC as 47 °C and 38.7 °C, respectively, whereas heat pipe showed values of 60 °C and 36.7 °C for max fin and water temperatures, respectively. Further performance enhancement to the U-Pipe ETC system was investigated through integration of phase change material (PCM)72 with added 1wt% multi-walled carbon nanotubes (MWCNT) nanoparticles. Peak temperatures recorded for this experiment were 63.9 °C and 43.3 °C for the U-Pipe fin and water tank, respectively. The results from this study show that the U-Pipe setup was able to achieve higher water temperatures than that of the HPETC setup. Incorporation of nano-PCM allowed for slower heat release in the water, extending useful duration of latent heat storage capability.

The ingenious combination of thermal energy storage and temperature visualization of binary fatty acid eutectic/eucalyptus wood fiber skeleton composites

The adjustment of temperature, reduction of supercooling, combination of energy storage characteristics and color change visualization are very valuable for integrating phase change materials into practical energy storage applications involving the optical field. In this respect, delignified eucalyptus (DEW) used as the supporting structure, and the binary fatty acid eutectic used as the phase change and discoloration temperature determining component, a series of red/green dibasic fatty acid reversible thermochromic phase change composites (CPCMs) were prepared by the vacuum impregnation method. Among them, two types of CPCMs (MPR-DEW and MPG-DEW) show the suitable phase change temperatures (42.1 °C, 42.3 °C), high latent heat values (130.3 J g−1, 130.6 J g−1), the supercooling degree (0.2 °C, 0 °C) lower than that of single fatty acid of MA (3.8 °C) and PA (2.9 °C). SEM, FTIR and XRD analysis show that the phase change-discoloration components are completely immersed in the honeycomb pore structure of the DEW and that no chemical reaction occurred during the impregnation process. After heating, the color of MPR-DEW and MPG-DEW changed from dark red to light red and dark green to light green, respectively. The difference between the red and green colors of MPR-DEW and MPG-DEW is reflected in the slight difference between light and heat absorption and storage. Moreover, MPR-DEW and MPG-DEW have very small changes in phase transition temperature and latent heat value before and after 50 heating-cooling cycles, maintaining good thermophysical properties and thermal stability, and have broad application prospects in building thermal management.

Investigation of physico-mechanical, thermal properties and solar thermoregulation performance of shape-stable attapulgite based composite phase change material in foam concrete

Thermal energy storage (TES) by means of phase change materials (PCM) is of great concern to decrease heating and cooling loads. In building envelopes, one of the most efficient TES methods is integration of PCMs with construction materials for preventing temperature fluctuations by taking advantage of energy storage/release feature of PCMs. Aim of this research was to develop novel foam concretes containing shape-stable attapulgite (ATP) based composite PCM as TES material. Shape-stable ATP/Capric-Myristic acid eutectic mix composite (ATP/C-M) was incorporated into foam concrete at three different ratios (15, 30 and 45 wt%) and characterized. Impacts of ATP/C-M inclusion on physico-mechanic and TES characteristics of foam concretes including composite PCM (FCPCM) were worked systematically. DSC results showed that ATP/C-M composite melts at 22.12 °C with latent heat storage capacity of 74.97 J/g, whereas FCPCM-45 melts at 21.05 °C with latent heat storage ability of 10.98 J/g. Inclusion of ATP/C-M instead of silica sand decreased flow diameter of foam concretes. Compared to reference mixture FCPCM-0, compressive strengths of FCPCM-15, FCPCM-30 and FCPCM-45 samples were reduced in the range of 11–46% while reduction in flexural strength was found to be about 35–57% at 28th day. All FCPCM samples showed lower thermal conductivity values than the specified value and could be defined as better insulation materials. Solar thermoregulation performances of foam concretes containing ATP/C-M were comparatively tested in laboratory and also actual ambient conditions. Results showed that foam concretes with acceptable mechanical properties can be used for internal temperature controlling and energy saving in buildings.