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The incorporation of phase change material (PCM) into building structures offers a pathway for passive energy storage, enabling adaptable indoor temperature control and alleviating energy consumption. Despite these advantages, the widespread adoption of PCM in building structures faces challenges due to extended payback periods. In this study, a novel and cost-effective salt hydrate PCM composite, comprised of calcium chloride hexahydrate–potassium chloride (CCH–KCl), was developed. Melamine foam (MF) and strontium chloride hexahydrate (SCH) were synergistically utilized to address phase separation and supercooling issues. Numerical simulations were conducted to assess the performance of the developed salt hydrate PCM composite in building partition walls. Specifically, incorporating a 20 mm-thick composite resulted in peak temperature reductions of 0.72 °C during normal operation and 1.01 °C during power outages compared to structures without PCM, accompanied by a substantial reduction in energy consumption by 5376.68 kWh/year. Moreover, the cost of the developed salt hydrate PCM is 89.33 % lower than industrial paraffin, and it reduces CO2 emissions by 1.40 kg/year/m2 compared to paraffin's 1.11 kg/year/m2. In summary, the developed salt hydrate PCM composite exhibits commendable thermal regulation and economic advantages in building applications, serving as a pivotal contributor to emission reduction efforts. [Display omitted] • Phase separation and supercooling issues of salt hydrate PCM were addressed. • Melting temperature of salt hydrate PCM was tailored for passive solar buildings. • Thermo-regulated performance of the salt hydrate PCM was evaluated. • The cost of the developed PCM is 89.33 % lower than that of industrial paraffin. [ABSTRACT FROM AUTHOR]

A shape‐stabilized composite phase change material (SS‐CPCM) with paraffin (PA) and biological porous carbon (BPC) was prepared. Freeze‐dried biological‐cellulose include abandoned pomelo peel (APP) and tangerine peel (ATP) were carbonized in vacuum at 800 °C to obtain BPC to be used as a matrix material to prevent PA leakage and enhance thermal conductivity. A vacuum impregnation process was utilized to obtain the SS‐CPCM. Scanning electron microscopy showed that BPC (carbonized APP is subsequently referred to as BPC1 and carbonized ATP as BPC2) has a porous, honeycomb‐like structure, and that the paraffin encapsulated by the pores is evenly distributed. The SS‐CPCM2 (made from ATP) had the highest thermal conductivity (2.10 W/m K), which is 1.89 and 10 times that of the SS‐CPCM1 (made using APP) and pure PA, respectively. Differential scanning calorimetry and thermo‐gravimetric analysis were applied to determine the thermal performance and thermal reliability of the SS‐CPCM. Therefore, the prepared SS‐CPCM has potential in the field of energy storage. [ABSTRACT FROM AUTHOR]

Phase‐change materials (PCMs) have been widely investigated as candidates for thermal energy storage and solar thermal energy conversion. However, low thermal conductivity and poor shape stability during phase transition processes are detrimental to their practical applications. In this study, we designed composite PCMs based on carbon foam (CF) via the vacuum impregnation method to overcome these problems. CF with 3D interconnected microporous structures and good compressive strength was fabricated from phenolic resin (PF) using a combined process of carbonization and sacrificial template techniques. The developer material is considered a promising support material for PCMs. The as‐prepared polyethylene glycol/CF composite (PCC) exhibited a high energy‐storage density with a melting enthalpy of 135.7 J/g, and the thermal conductivity was enhanced by 109.8% compared to that of pure polyethylene glycol. In addition, the PCC showed excellent thermal stability and leakage‐proof performance after 100 heating/cooling cycles and good compressive strength. Because of the simple preparation process and low cost, PCC is a promising material for various thermal energy storage applications, especially in building energy storage systems. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Carbonization corn cobs were a perfect carrier matrix to form shape stabilized PCMs. • Carbonization corn cobs exhibit a highly porous structure comprising rough micropores. • Latent heat, stability, and thermal properties of PCMs were excellent. • The thermal conductivity of LA-SA/CNCC was 87.5% greater than that of LA-SA. Abstract In this study, novel form-stable composite phase change materials (FS-CPCMs) were prepared by the incorporation of a eutectic mixture of lauric-stearic acid (LA-SA) into carbonization corn cob (CNCC). CNCC served as a good supporting material that not only prevented the leakage of LA-SA but also enhanced its thermal conductivity. Scanning electron microscopy results demonstrated that CNCC exhibits a highly porous structure comprising rough micropores. The retention of 77.9 wt% of LA-SA in CNCC without leakage was observed. Differential scanning calorimetry results revealed that LA-SA/CNCC FS-CPCMs melt at 35.1 °C with a latent heat of 148.3 J/g and solidify at 29.7 °C with a latent heat of 144.2 J/g. The thermal conductivity of LA-SA/CNCC FS-CPCMs was approximately 87.5% greater than that of LA-SA. Thermogravimetric analysis and 200-cycle experiments indicated that the LA-SA/CNCC FS-CPCMs exhibit excellent thermal stability and form-stable performance. Therefore, the as-prepared LA-SA/CNCC FS-CPCMs demonstrate promise for building energy-efficiency applications. [ABSTRACT FROM AUTHOR]

An innovative way to enhance the thermal conductivity of composite phase change materials (PCMs) is by carbonizing the carbohydrate-coated mineral substrate to modify its porous structure. Here, we study the effect of introducing different amounts of carbonized starch acting as a filler for enhancing the thermal conductivity of the shape-stabilized composite PCMs (ss-CPCMs) based on polyethylene glycol (PEG) and modified expanded vermiculite (MEV). The experimental exploration of the thermal behavior of composite PCMs has been explored sufficiently in depth. The MEV is shown by SEM images to tightly adhere to the carbon layer and to be composed of a dense micropore structure. Results from DSC indicate that the latent heat of the PEG/MEV ss-CPCMs gradually decreases with the increase of carbon layer mass fraction. Results obtained from FT-IR and TGA show that PEG/MEV ss-CPCMs exhibit good chemical and thermal stabilities. The thermal conductivity of the PEG/MEV ss-CPCMs increases with the carbon layer mass fractions and reaches up to 1.94 times that of PEG/EV ss-CPCMs. The PEG/MEV ss-CPCMs result in a promising material for applications in energy-efficient buildings due to its excellent thermal properties, ideal thermal conductivity and good chemical and thermal stability. [ABSTRACT FROM AUTHOR]

In this research, a novel form-stable composite Phase change material (PCM) of Stearic Acid (SA)/Carbonized sunflower straw (CSS) was prepared by vacuum impregnation method. Fourier Transform Infrared Spectroscopy (FT-IR) was used to measure the chemical compatibility of SA/CSS. The thermal properties and thermal stability were investigated by differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) techniques. The results show that the SA/CSS melted at 66.4 °C with the latent heat of 186.1 J/g and freezed at 65.9 °C with the latent heat of 186.7 J/g and the composite PCM have a good thermal reliability above its working temperature. Moreover, the thermal conductivity of SA/CSS was 0.33 W/m/K which was 106.3% higher than that of SA. All results indicated that SA/CSS have suitable thermal properties used as thermal energy storage applications such as solar heat energy storage system and energy conservation buildings. [ABSTRACT FROM AUTHOR]

[Display omitted] Organic phase change materials (PCMs) have attracted considerable attention for thermal energy storage applications because of their non-toxicity, suitable working temperature range and excellent thermal/chemical stability. However, most traditional organic PCMs have small molecular structures and are prone to leakage during fusion. To address this problem and enhance the shape-stability of organic PCMs, nanosphere-shaped porphyrin-ferrocenyl conjugated microporous polymers (PFCMPs) with high porosity (~ 650 m2/g) were solvothermally synthesized using a Diels-Alder reaction between 1,1′-ferrocenedicarboxaldehyde and pyrrole in the presence of glacial acetic acid and anhydrous Lewis acids (FeCl 3 , AlCl 3 , and CuCl 2). The PFCMPs were then encapsulated with PCMs, that is, 1-octadecanol (ODA), to prepare the composite materials of ODA@PFCMPs. The optimized composite exhibited a high latent heat (up to 153.8 J/g), excellent reversibility (negligible change in latent heat upon 100 cycles of heating–cooling), good shape stability, and long heat storage durability (425 s), making it a promising candidate for solar thermal energy engineering and management. [ABSTRACT FROM AUTHOR]

In this study, novel form stable composite phase change materials (FS-CPCMs) from palmitic-lauric acid (PA-LA) eutectic mixture and carbonized abandoned rice (CAR) were prepared via vacuum impregnation. The CAR served as a good supporting material to prevent PA-LA from leaking and enhanced the thermal conductivity of PA-LA. SEM results showed that the CAR has a highly porous structure consisting of rough micro-pores and PA-LA did not leak from the CAR during the solid-liquid phase transition. DSC indicated that the latent heat and temperature of PA-LA/CAR FS-CPCMs during melt were 135.4 J/g and 34.3 °C, respectively, whereas, these values were 124.8 J/g and 28.6 °C during freezing, respectively. The thermal conductivity of PA-LA/CAR FS-CPCMs was 1.83 times that of PA-LA. The heat storage/release rate of the PA-LA/CAR FS-CPCMs is significantly more than that of PA-LA for practical applications. The results obtained from FTIR demonstrated that no new chemical bonds were formed between PA-LA and CAR. TGA and 200-cycle experiments showed that the PA-LA/CAR FS-CPCMs exhibit excellent thermal stability and form-stable performance. The PA-LA/CAR FS-CPCMs thus prepared were safe, environmentally friendly, and cost-effective; hence, they can be used as potential building materials for the applications of thermal energy storage. [ABSTRACT FROM AUTHOR]