This study presents the development and detailed thermal evaluation of ultra-high-concentration eicosane phase change material (PCM) nanoemulsions enhanced with multi-walled carbon nanotubes (MWCNTs), aiming to advance thermal energy storage (TES) performance in net zero energy building (NZEB) applications. Nanoemulsions were prepared with varying eicosane concentrations (10–50 wt%) and MWCNT concentrations (0–0.2 wt%). DSC results revealed that the LHF increased substantially with higher eicosane content, reaching 138.5 J/g at 50 wt% eicosane with 0.2 wt% MWCNT, compared to 116.1 J/g without MWCNT, while pure eicosane exhibited an LHF of 251.3 J/g. Notably, the addition of MWCNTs led to a dramatic reduction in the Tsc, decreasing from 13.5 °C in emulsions without MWCNTs to as low as 0.4 °C at 0.2 wt% MWCNT, marking a ∼ 97 % improvement. Dynamic light scattering (DLS) analysis showed that droplet size increased from 588.2 nm at 0 wt% MWCNT to 767 nm at 0.2 wt% MWCNT for the 50 wt% eicosane system while maintaining excellent dispersion stability, as indicated by zeta potential values between − 70.76 and − 62 mV. Viscosity measurements demonstrated that at 50 wt% eicosane, viscosity rose from 20 mPas (without MWCNT) to 142 mPas at 0.2 wt% MWCNT, reflecting the formation of a stable nanoparticle network that supports structural integrity without hindering pumpability.

The enhancement of phase change materials (PCMs) by adding nanoparticles presents a potential option for improving thermal energy storage (TES) systems. This study investigated the thermal performance of eicosane PCM nanoemulsions improved with multi-walled carbon nanotube (MWCNT) introduced at different stages of the preparation process. Besides, the research examines the impact of MWCNT addition timing on the thermal properties and dispersion stability of the resulting nanoemulsions. As a result, the optimal composition was determined to be MWCNT@PCM-ED, with MWCNT and PCM concentrations of 0.2 wt% and 50 wt%, respectively. The results show that the timing of MWCNT addition significantly impacts the thermal characteristics of the PCM nanoemulsions. PCM emulsions with MWCNTs added during pre-emulsification exhibited the highest improvement in thermal characteristics, while those with post-emulsification addition showed relatively lower enhancement. The degree of supercooling in MWCNT@PCM-ED, consisting of 0.2 wt% MWCNT and 50 wt% eicosane, was reduced from 8 to 0.4 °C compared to pure eicosane PCM. However, the latent heat of fusion for MWCNT@PCM-ED decreased from 251.3 to 138.5 J/g relative to pure eicosane PCM. These results are crucial for developing high-performance PCM nanoemulsions for TES applications.

The development of high-performance phase change materials (PCMs) with improved thermal conductivity and structural stability is crucial for next-generation thermal energy storage and management systems. Here, we present a simple, energy-efficient, microwave-assisted one-pot synthesis of shape-stabilized composite PCMs (SSCPCMs) based on eicosane (EI), expanded graphite (EG), and boron nitride (BN) nanoparticles. The combined effect of EG's high thermal conductivity and porous structure with BN nanoparticles' thermal stability helps form multifunctional composites with better energy storage and heat dissipation. Morphological and structural analyses confirm the uniform dispersion of BN nanoparticles and the effective containment of EI within the EG matrix, thereby maintaining the crystalline and chemical integrity of each component. The resulting SSCPCMs exhibit high latent heat (up to 253.3 kJ kg−1 for EI/EG15) and significantly enhanced thermal conductivity (up to 4.5 W m−1 K−1 for EI/EG25/BN5), demonstrating tunable thermal properties depending on the composite composition. Thermogravimetric and thermal imaging tests further confirm their enhanced thermal stability and excellent shape retention at high temperatures. The adjustable thermal properties and structural durability of these SSCPCMs, combined with a straightforward and energy-efficient manufacturing process, make them ideal for advanced thermal energy storage and battery cooling applications, especially in electric vehicles and portable electronics.

Due to the versatile applicability of phase change material emulsions (PCMEs) in various thermal management applications, researchers focus on developing and investigating new highly efficient PCMEs. In the present research, PCME at different concentrations was prepared using n-Hexadecane as phase change material (PCM) and deionized water as base fluid. Sodium dodecyl sulfate is used to stabilize the PCM in the base fluid. The average PCM droplet size and corresponding zeta potential for PCME at 50 wt% concentration were 166 nm and –49 mV, respectively, whereas the onset melting and freezing points were 289 and 286 K, respectively. The latent heat of PCME was reduced compared to pure PCM. The thermogravimetric results confirm that decomposition occurs above 373 K and slow evaporation may occur at lower temperatures. Also, there is no chemical interaction between the components of the PCME. Therefore, the developed PCME can be an excellent heat accumulation and transportation medium.

High-temperature solar thermal systems are a key component of using solar energy for many industrial uses, such as process heat, desalination, and power production. However, the performance of these systems significantly relies on the properties of the heat transfer fluid (HTF) employed. Conventional HTFs, including molten salts and synthetic oils, have drawbacks that prevent them from being widely used, like low thermal stability, corrosion problems, and high viscosity at high temperatures. To overcome these challenges, scientists focus on developing novel HTFs with enhanced thermal stability, improved heat transfer properties, and reduced environmental impact. One of the promising strategies involves using nanofluids, which are colloidal suspensions of nanoparticles in a base fluid. Compared to traditional HTFs, nanofluids exhibit better thermal conductivity, making them attractive options for high-temperature solar applications. Liquid metals are another attractive avenue for the exploration of advanced HTFs. Efforts are being made in combinatorial material synthesis and high-throughput characterization techniques to identify optimal compositions of liquid metals. Moreover, research is being done to investigate alternative base fluids that provide better thermal stability and compatibility with solar collector materials, such as eutectic mixtures and organic compounds. Computational modeling and experimental studies are being conducted to comprehend the basic mechanisms governing heat transfer and fluid behavior in high-temperature solar systems using advanced HTFs. The development of advanced HTFs holds great potential for improving high-temperature solar thermal systems’ efficiency, reliability, and cost-effectiveness, facilitating the transition toward a sustainable energy future. Continued research and innovation in this area are crucial to unlocking the full potential of solar energy as a clean and ample renewable energy source for meeting global energy demands. Comprehensive information on the development of advanced HTFs for high-temperature solar thermal systems is presented in this chapter.

Parabolic trough collectors are a well-established solar concentrating technology widely utilized for efficiently harnessing solar energy. The increasing demand for sustainable energy solutions has spurred extensive research into optimizing parabolic trough collector performance for diverse applications. This paper examines the fundamental principles of parabolic trough collectors and reviews advancements to improve their efficiency. The potential of parabolic trough collectors to harness solar energy efficiently and contribute to sustainable energy solutions motivates the exploration of innovative design and operational strategies. Additionally, enhancements to heat transfer structures, such as using volumetric absorption methods with nanofluids and metal foam in the receiver, significantly boost absorption and energy transfer. The method involves analyzing comparative studies that test various models, working fluids, and structural modifications in parabolic trough collector systems. Results highlight the potential of these advancements to increase thermal efficiency and overall energy output. The findings underscore the importance of parameter optimization in achieving superior parabolic trough collector performance. This review provides a comprehensive overview of current advancements, offering valuable guidance for future research and development in solar energy technologies.

Thermal energy storage (TES) is a key technology in the pursuit of cleaner energy production that enables the more efficient use of renewable energy sources and reduces reliance on fossil fuels. Phase change material emulsions (PCMEs) are studied as TES and transportation mediums. A stable PCME with n-hexadecane (HXD) as a dispersed phase and deionized water as base fluid was successfully fabricated using sodium dodecyl sulfate as a surfactant. Functionalized multi-walled carbon nanotubes (F-MWCNT) were incorporated into the emulsion as an additive to reduce supercooling and enhance thermal conductivity (TC). The prepared emulsions were analyzed in terms of droplet size distribution, phase change properties, stability, TC, and viscosity. The surfactant significantly improved the PCME stability and prevented phase separation. The average droplet size and zeta potential for PCME without nano additive were 166.9-202.2 nm and -67.56 mV, respectively, whereas for PCME with F-MWCNT, 183.41-188.73 nm and -49.53 mV, respectively. The latent heat increased as the concentration of the dispersed phase PCM was higher. The underlying mechanism for the TC enhancement of 22.9 % with the addition of F-MWCNT was investigated. The findings suggest that the developed PCME with F-MWCNT is a promising candidate for TES applications, offering efficient energy management and enhanced thermal performance.

This study analyzed the correlation between various design parameters and cooling performance (CP) of the immersion cooling system for thermal management of lithium-ion batteries (LIBs), theoretically. The Multi-Scale Multi-Dimensional (MSMD) Newman, Tiedeman, Gu, and Kim (NTGK) empirical model was used to consider the electrochemical heating of the battery. The CP of the immersion cooling system was analyzed according to the inlet/outlet location, dielectric fluid, cell spacing, C-rate, and mass flow rate (MFR). As a result, the Z-type inlet/outlet location, Novec 649 dielectric fluid, and 2 mm cell spacing were most suitable. As the mass flow rate increased, the maximum battery temperature (Tb.max) was confirmed to remain within the appropriate operating temperature range of 45 °C or lower for battery operation. However, under discharge conditions of 4 C-rate or higher, the temperature difference between battery cells (Tb.diff) significantly exceeded the safety limit of 5 °C. Additionally, as the mass flow rate of dielectric fluid increased, Tb.max and Tb.diff decreased by 20.6 % and 50.6 %, respectively. The impact of design parameters on CP was analyzed, and based on the simulation results, a prediction equation was developed to predict Tb.max and Tb.diff, which have a high correlation of over 0.908.

Phase change material (PCM) emulsions have grown in popularity due to their versatility and various thermal management applications. Therefore, new PCM materials and emulsion compositions have been investigated to enhance their functionality and widen their range of applications. In the present work, PCM emulsion was formulated using n-heptadecane as a dispersed phase, DI-water as base fluid, and sodium dodecyl sulfate and Brij30 as surfactant. The effect of mixed surfactants on the stability and other thermophysical properties of the PCM emulsions were investigated. The emulsions with mixed surfactants show excellent stability when compared to single surfactants. The average droplet size of the PCM emulsion was 102.8 nm with a phase change temperature and latent heat of fusion of 18.9 °C and 14.17 Jg−1, respectively, for 10 wt% PCM concentration. The thermal conductivity was decreased by about 16.4 %, and the viscosity increased by nearly 128 % when compared with DI-water for the 10 wt% dispersed phase emulsion with mixed surfactants. The gravimetric and structural studies confirm the stability of dispersed phase and base fluid in the presence of surfactant. Overall, it can be concluded that the PCM emulsion with mixed surfactant can be a potential heat transfer medium with improved heat storage and transportation capacity.

Thermal energy storage (TES) using phase change materials (PCMs) is one of the potential solutions for stockpiling thermal energy and utilizing it for different applications, which results in effective energy usage. The main drawback of organic PCMs in practical applications is poor heat transfer due to low thermal conductivity (TC). Therefore, investigations into nano-enhanced PCMs are being explored to improve their thermophysical properties. In this work, the various thermophysical characteristics of nano-enhanced lauryl alcohol as a PCM were investigated using carbon-based and metallic nanoparticles. The results indicated that the addition of nanoparticles improved its thermal properties and affected other physical properties, such as viscosity. The latent heat was degraded with the addition of nanoparticles. The results revealed that by adding MWCNTs and CuO nanoparticles, a maximum of 82.6% and 49.6% improvement in TC was achieved, respectively. The maximum drop in latent heat during melting and freezing for the PCM with MWCNTs was about 10.1% and 9.3%, respectively, whereas for the PCM with CuO, they were about 11% and 10.3%, respectively. The lowest supercooling for the PCM with MWCNTs and CuO nanoparticles was 8.6 and 8.3 °C, respectively. The present work confirms that nano-enhanced PCMs can be a potential material for storing thermal energy for various applications.

This research investigated the potential of high-energy-density Paraffin-based four different phase change materials (PCMs) (Paraffin 56/58, n-Eicosane, n-Octadecane, and n-Heptadecane) emulsions as a promising heat transfer fluid for low and medium-temperature applications at different concentrations. The primary focus is on elevating efficiency and sustainability within this domain. The investigation revolves around formulation and characterizations of these PCM emulsions, meticulously assessing their thermal attributes and stability. The results showed that producing these PCM emulsions using a high-energy manufacturing method with surfactant achieved superior dispersion stability and uniform size distribution throughout PCM emulsions. Among the pristine PCMs, n-Eicosane exhibited the highest latent heat of 252.7 kJ/kg during the melting process. In comparison, other PCMs, Paraffin 56/58, n-Octadecane, and n-Heptadecane demonstrated latent heat fusions of 197.7, 244.3, and 221.3 kJ/kg, respectively. Moreover, the energy storage density of PCM emulsions increased with increasing PCM concentration in basefluid. The highest energy storage density was observed in the case of 70 wt% n-Eicosane PCM emulsion, which is 401.1 kJ/kg. By examining the effectiveness of Paraffin-based PCM emulsions, this research aims to contribute to advancing eco-conscious and effective thermal management systems across diverse applications.

Developing competent energy storage materials is crucial for efficient thermal energy storage and utilization. Microencapsulated lauryl alcohol as phase change material using SiO2 shell was prepared through a novel one-pot synthesis of interfacial polycondensation using tetraethyl orthosilicate as a shell precursor. The thermal properties were analyzed through differential scanning calorimetry, which revealed that the melting and freezing points of microcapsules were 23 °C and 18.9 °C, respectively. For melting and freezing, the estimated latent heats were 90 J g−1 and 88.2 J g−1, respectively. Thermogravimetric analysis confirms that the microcapsules are stable at a higher temperature. Besides, the leak test of the developed microcapsules was performed to investigate the stability during the melting process. Moreover, the prepared microcapsules (MPCM2) show stable and excellent thermophysical properties after 500 thermal cycles, which shows that the developed microcapsule is an ideal candidate for thermal energy storage. Graphical abstract: (Figure presented.)

Thermal energy storage systems play a crucial role in energy conservation and balancing energy demand/supply. Recent thermal storage techniques and novel strategies have expanded their usage in various applications. However, leakage during phase change and poor thermal conductivity limits using phase change materials (PCM) as a potential thermal storage medium. Shape-stabilized phase change materials (SSPCM) can effectively enhance heat transfer and prevent leakage. Besides, it provides flexible structures, good mechanical strength, and stability. Furthermore, loading a maximum quantity of PCM in the support structure enables improved efficiency of SSPCMs and enhances heat transportation. In this review work, SSPCMs and different types of support structures used to prepare SSPCM are discussed and presented with their advantages and disadvantages. It is also aimed to provide comprehensive information on microencapsulation techniques, metallic, carbon-based, and polymeric support employed in SSPCM preparation. This review also sheds some light on the applications of SSPCM, more specifically, thermal management and storage. Finally, the future scope of research on SSPCM is briefly discussed. It is believed that the information presented in this review will help the readers to understand SSPCM and different support structures for SSPCM preparation, along with various application techniques.

In this paper, a water thermal seat is proposed to increase thermal comfort in automobiles. In order to confirm the applicability of a water thermal seat, a numerical study was conducted on the driver’s thermal comfort according to the use of the basic seat and water thermal seats (hot and cold water seats) in the car cabin under summer and winter conditions. As a result, after an elapsed cooling time of 30 min under summer condition, the predicted percentage of dissatisfaction (PPD) using the cold water seat was reduced by 23.4 % compared with that when using the basic seat. In winter, a slight dissatisfaction with the PPD (10.1 %) was presented for the basic seat, compared to 7.8 % in the initial 5 min when the hot water seat was used. Therefore, it was confirmed that the simultaneous use of HVAC and water thermal seats during summer and winter could significantly reduce the discomfort of the driver at the beginning of driving.

Implementing renewable energy systems is significantly increased worldwide to address various environmental issues. The capacity of renewable power source installation expanded in recent times and tends to increase in the future. Therefore, it is necessary to optimize renewable energy generation and system flexibility so that it can be utilized safely. Efficient utilization of renewable energy will result in minimized environmental impact and increased reliability on the power grid. Internet of Things (IoT) facilitates integrating the different renewable energy sources and helps in the uniform distribution of available energy to the targeted beneficiaries when needed. It also improves the energy efficiency of the renewable system by effective management of generation, transmission, supply, and demand. This chapter discusses and highlights the role of IoT in the renewable energy sector.

This study discusses the preparation and thermophysical characterization of microencapsulated stearyl alcohol (SA) for thermal energy storage and heat transportation applications. The developed microcapsules consist of SA, an organic phase change material (PCM) core material, and melamine formaldehyde (MF) shell material. The PCM microcapsules have been synthesized using sodium dodecyl sulfate as a surfactant using an in-situ polymerization technique and subjected to various thermal and structural characterization techniques. The results revealed that prepared microencapsulated PCM (MPCM) with 0.25 g of surfactant and 5 g of PCM exhibits better morphological structure with an average diameter of 4.7 µm. The onset melting point and latent heat were estimated as 42 °C and 137.7 Jg−1, respectively. The highest encapsulation ratio of 51.9 % and 52.3 % were observed for the core to the shell ratio of 5:8.4. The MPCMs are thermally stable and the decomposition temperature of the MPCM was higher than the pure PCM. The developed MPCM shows good chemical stability and no leakage during the phase change process. The obtained results elucidate the suitability of the developed MPCM in thermal energy storage applications.

In order to recover and reuse refrigerants that accelerate global warming, it is necessary to absorb refrigerants and separate mixed refrigerants. Therefore, this study evaluated the performances of 1-hexyl-3-methylimidazolium (HMIM)-based ionic liquids [HMIM][BF4], [HMIM][PF6], and [HMIM][Tf2N] for the selective absorption of R134a and R1234yf refrigerants. According to the experimental results, refrigerant absorption depended on the viscosity of the ionic liquid, the molecular structure and temperature of the refrigerant, and the pressure. As Henry's law constant decreased, the refrigerant-absorption performance of the HMIM-based ionic liquids increased. In addition, [HMIM][Tf2N] and [HMIM][BF4] exhibited the highest absorption performance of refrigerants per hour at 300 and 400 kPa, respectively. R134a demonstrated better refrigerant-absorption performance than R1234yf, which indicates the possibility of selective separation using ionic liquids.

To evaluate a potential thermal battery material for thermal energy storage applications, this study prepared a stable organic nano-dispersed PCM (NDPCM) with 1-tetradecanol (TD) with a melting point and latent heat of 37.8 °C and 236.4 J/g, respectively, as base PCM and investigated its thermal properties. The high thermal conductive nano-additives of functionalized multi-walled carbon nanotubes (MWCNT-COOH) with a concentration range of 1 wt% to 5 wt% were infused in the pure PCM. As a result, MWCNT-COOH shows better dispersion stability. The SEM microimage confirms no agglomeration was observed for the prepared NDPCM. The supercooling was reduced from 10.6 °C for the pure TD to 7.7 °C for TD with 5 wt% of MWCNT. The latent heat of the NDPCM with 5 wt% MWCNT-COOH was 212.6 J/g with a 10% reduction compared to pure TD. The reduction in latent heat values is lower than the previously investigated TD composite PCM. The thermal stability study through gravimetric analysis confirms that the decomposition of the NDPCMs initiates at 200 °C, which will not be affected by thermal fluctuation in the system. The sample with 5 wt% of nano-additives had the most excellent thermal conductivity (TC) improvement, 56.2% in the liquid phase, whereas 50% in the solid phase. The reported values are significantly higher compared to the previous thermal conductivity improvement of TD using metallic nanoparticles. The prepared NDPCM shows better thermal properties than the pure PCM and can be a possible material for high-density thermal energy storage applications.

The present work discusses the experimental investigation of the convective heat transfer (CHT) and pressure drop characteristics of a hybrid nanofluid (HNF). The multi-walled carbon nanotube (MWCNT) NF, Fe3O4 NF, and MWCNT/Fe3O4 HNFs with 0.025 wt% to 0.2 wt% concentrations were prepared through ultrasonic dispersion. The CHT coefficient of the three NFs was investigated in a cylindrical test section at different Reynolds numbers (Re) and compared. As an outcome, the CHT coefficients of the MWCNT/Fe3O4 HNFs ranged from 1823.2 to 2030.5 W/m2·K, which is 6%–15.9% more than the base fluid. Furthermore, the MWCNT/Fe3O4 HNFs outperformed the MWCNT and Fe3O4 NFs individually during the CHT coefficient enhancement. At Re of 1000–1600, the increase in pressure drop of the MWCNT NF, Fe3O4 NF, and MWCNT/Fe3O4 HNFs varied from 62.4% to 91.7% as compared to water. Therefore, it is expected that the MWCNT/Fe3O4 HNF could be an effective heat transport medium.

This study examined the thermal performance of a slurry containing micro-encapsulated phase change materials (me-PCMs) for thermal energy storage (TES) applications such as solar thermal or PVT systems. Specifically, the study focused on stearic acid (SAC) and stearyl alcohol (SAL) as the phase change materials, dispersed within an ethylene glycol aqueous solution. The research revealed that increasing the concentration of PCM in the slurry led to improved latent heat energies for both micro-encapsulated stearic acid (me-SAC) and micro-encapsulated stearyl alcohol (me-SAL) slurries during melting and solidification processes. Moreover, me-SAL slurries exhibited higher latent heat energies compared to me-SAC slurries at the same concentrations. The addition of CTAB surfactant positively influenced the stability of the slurry dispersion, ensuring a more even distribution of me-PCMs within the base fluid. These findings highlight the potential of me-SAC and me-SAL slurries as effective materials for TES applications. Significantly, me-SAL slurries outperformed me-SAC slurries in TES performance due to their greater latent heat energies during melting and solidification.

This work presents the preparation of microencapsulated phase change material (MPCM) of lauryl alcohol by using melamine formaldehyde (MF) as shell material. The microstructure, size, and surface morphology of MPCM were analyzed through microscopic analysis, confirming spherical structure and smooth surface. The thermal properties of the MPCM were studied using calorimetric and gravimetric analysis. The melting point and latent heat of fusion of the prepared MPCM were 20.4 °C and 90.53 Jg–1, respectively. MPCM exhibits good thermal stability up to 175 °C without decomposition. Furthermore, the Fourier transform infrared (FT-IR) spectroscopy results showed no chemical reaction between the core phase change material (PCM) and shell material. The leak test proved that the phase change occurs inside the microcapsules without leakage. These obtained results confirm that the prepared MPCM is suitable for thermal energy storage material.

This paper investigates the thermal properties enhancement of lauryl alcohol, which falls in the category of organic fatty alcohol as an energy storage material for latent heat thermal energy storage using multi-walled carbon nanotubes (MWNCTs) nanoparticle additive. Nano-enhanced PCMs of lauryl alcohol with different concentrations of MWCNTs ranging from 1 wt% to 5 wt% were prepared, and the thermophysical properties were studied using various characterization techniques. From the result, it was found that the thermal conductivity of the lauryl alcohol can be significantly increased with the addition of MWCNT. The maximum increment in thermal conductivity was observed for 5 wt% MWCNT. The chemical structure was not altered by the addition of MWCNT and Gum Arabic. However, the concentration of nanoparticles affects several other important properties such as latent heat and degree of supercooling. Therefore, the optimum concentration of the nanoparticle has to be carefully determined for better thermal properties. The detailed investigation on the nano-enhanced lauryl showed that the lauryl alcohol with MWCNT could be a potential PCM for cold thermal storage applications.

This experimental work discusses the thermophysical investigation of metallic nanocomposite PCMs having a potential application in indoor thermal management. Organic fatty alcohol (lauryl alcohol) was used as a phase change material (PCM). Four metallic nanoparticles, namely Al2O3, CuO, Fe3O4, and SiC at the concentrations of 1 wt%, 3 wt%, 5 wt%, were used to prepare nanocomposite PCMs, and their phase change properties were investigated. The results showed a minor change in the phase change temperatures, and the latent heat values varied between 6.56% and 18.5%. Besides, the degree of supercooling was reduced for nanocomposite PCMs. Fourier transform infrared spectroscopy, and thermogravimetric analysis showed no chemical reaction between the nanoparticles and the base PCM. The nanocomposite PCMs decomposed above 110°C, higher than the proposed application temperature range. In addition, the maximum enhancement in thermal conductivity of PCM at 10°C with 5 wt% of Al2O3, CuO, Fe3O4, and SiC nanoparticles were about 29.1%, 52.2%, 9.2%, and 17.9%, respectively. The endothermic freezing process was carried out, and lower phase change duration was recorded for nanocomposite PCMs compared to pure PCM. Based on various experimental studies, Al2O3 and CuO nanocomposite PCMs exhibits significantly improved thermal and physical properties than the Fe3O4 and SiC nanocomposite PCMs and can be used as a potential thermal energy storage material for indoor thermal comfort applications.

This study aims to prepare a stable caprylic acid (CA) and cetyl alcohol (CAL) organic binary mixture as a solid–liquid phase change material (PCM) with a phase transition temperature in the range for exotic chilled refrigeration. A detailed study was carried out on the thermo-physical properties, thermal reliability and corrosion analysis of the prepared binary mixture. The result showed that the binary mixture of caprylic acid–cetyl alcohol (CA–CAL) with a eutectic point at 85:15 molar mass ratio is suitable for medium-range refrigeration application. The determined onset melting/freezing temperature with differential scanning calorimetry (DSC) was 10 °C/8.9 ± 0.1 °C with a phase transition enthalpy of 154.1/153.3 ± 1% J/g. The binary mixture thermal conductivity measured in the solid phase (at 0 °C) and liquid phase (at 20 °C) was (0.288 ± 0.028) and (0.156 ± 0.007) W/(m⋅K), respectively. Moreover, the thermal reliability test result of the prepared binary mixture under accelerated thermal cycling for 500 melting/freezing cycles showed a maximum of 10.1% deviation in thermal properties, which was in the acceptable range for organic binary PCM. The prepared PCM was found to be compatible with stainless steel and aluminum over an extended period of time, based on corrosion tests conducted on aluminum, copper and stainless steel over a period of 84 days. According to this study, the binary combination CA–CAL as PCM is a potential candidate for cold chain food transportation, supermarket cold cabinets, and other refrigeration applications.

Multi-walled carbon nanotube (MWCNT) enhanced 1-hexyl-3-methyl-imidazolium cation-based room temperature ionic liquids (RTILs) with different anions were investigated for CO2 capture. Besides, the viscosity, surface tension, and thermal stability of the samples were also investigated. Moreover, the behavior of CO2 bubbles captured and analyzed. Among various pristine RTILs, [HMIM][Tf2N] exhibited better CO2 capture capability compared to other ionic liquids; hence, MWCNT/[HMIM][Tf2N] nanoparticle enhanced ionic liquids (NEILs) were prepared and tested for CO2 absorption. As a result, the highest CO2 absorption capability or pressure reduction was observed at the pressure and MWCNT nanoparticles concentration of 1 MPa and 0.05 wt%, respectively. At the system pressure of 0.35, 0.6, and 1 MPa, the CO2 absorption capacities of 16.17%, 23.13%, and 31.30% were obtained at the temperature of 20 oC, 50 oC, and 20 oC, respectively, for 0.05 wt% MWCNT/[HMIM][Tf2N] NEIL. Furthermore, it was deduced that the effect of pressure and MWCNT nanoparticle concentration was superior to the temperature effect on the CO2 absorption capability of MWCNT/[HMIM][Tf2N] NEILs.

The wise use of energy is essential to address the problem of a steady increase in global energy demand. Efficient technologies are required to extract energy from the resources and utilize in effective ways. Energy storage systems help to build a more robust energy grid and save costs for utilities and consumers. The major portion of end-use energy is thermal energy and storing it aids in the effective utilization of available resources. Thermal energy storage (TES) is used in load leveling where there is a mismatch between energy demand and energy generation. There are different types of TES techniques in practice. The selection of a TES technique depends on the type of application, duration, size, etc. This chapter provides an insight that focuses on TES, different types of TES techniques, and its various applications in increasing the energy efficiency.

This paper discusses the forced convective heat transfer characteristics of water–ethylene glycol (EG)-based Fe3 O4 nanofluid and Fe3 O4 –MWCNT hybrid nanofluid under the effect of a magnetic field. The results indicated that the convective heat transfer coefficient of magnetic nanofluids increased with an increase in the strength of the magnetic field. When the magnetic field strength was varied from 0 to 750 G, the maximum convective heat transfer coefficients were observed for the 0.2 wt% Fe3 O4 and 0.1 wt% Fe3 O4 –MWNCT nanofluids, and the improvements were approximately 2.78% and 3.23%, respectively. The average pressure drops for 0.2 wt% Fe3 O4 and 0.2 wt% Fe3 O4 – MWNCT nanofluids increased by about 4.73% and 5.23%, respectively. Owing to the extensive aggregation of nanoparticles by the external magnetic field, the heat transfer coefficient of the 0.1 wt% Fe3 O4 –MWNCT hybrid nanofluid was 5% higher than that of the 0.2 wt% Fe3 O4 nanofluid. Therefore, the convective heat transfer can be enhanced by the dispersion stability of the nanoparticles and optimization of the magnetic field strength.

This article presents the experimental charging and discharging characteristics of two organic phase change materials (PCMs) for the application of cold thermal energy storage. Lauryl alcohol and butyl stearate were encapsulated in rectangular encapsulation and the experimental study was carried out in vapor compression refrigeration system. The experiment also conducted for different masses of PCMs and the result showed that lauryl alcohol shows stable phase change with less temperature variation of 3.5°C during the charging and discharging which is not evidenced in butyl stearate. Also, the discharging duration is more in lauryl alcohol than butyl stearate due to its high energy density. The discharge in lauryl alcohol occurs for more than two times of the discharge time of the butyl stearate. Both the PCMs produced cooling inside the chamber during the experiment but comparatively lauryl alcohol advances in the real-time performance and recommended for cold thermal energy storage applications.

Sorption thermochemical storage systems can store thermal energy for the long-term with minimum amount of losses. Their flexibility in working with sustainable energy sources further increases their importance vis-à-vis high levels of pollution from carbon-based energy forms. These storage systems can be utilized for cooling and heating purposes or shifting the peak load. This review provides a basic understanding of the technologies and critical factors involved in the performance of thermal energy storage (TES) systems. It is divided into four sections, namely materials for different sorption storage systems, recent advances in the absorption cycle, system configuration, and some prototypes and systems developed for sorption heat storage systems. Energy storage materials play a vital role in the system design, owing to their thermal and chemical properties. Materials for sorption storage systems are discussed in detail, with a new class of absorption materials, namely ionic liquids. It can be a potential candidate for thermal energy storage due to its substantial thermophysical properties which have not been utilized much. Recent developments in the absorption cycle and integration of the same within the storage systems are summarized. In addition, open and closed systems are discussed in the context of recent reactor designs and their critical issues. Finally, the last section summarizes some prototypes developed for sorption heat storage systems.

In this work, the magnetic field effect on the convective heat transfer (CHT) properties of nanofluids comprising cobalt–zinc ferrite nanoparticles were experimentally studied. The nanofluid was prepared by dispersing the cobalt–zinc ferrite nanoparticles in the water and ethylene glycol mixture (80:20) and subjected to heat transfer studies. The experiment result exhibited that the CHT coefficient increased with the increase in the nanofluid concentration. The maximum CHT coefficient exhibited at a concentration of 0.2 wt%, which was improved by about 23.9%. It was also found that the CHT coefficient at a magnetic field of 750 G was increased by about 2.64% compared to that at 0 G for 0.2 wt% cobalt–zinc ferrite nanofluid concentration. The nanofluid with 0.2 wt% cobalt–zinc ferrite concentration exhibited the maximum CHT coefficient and pressure drop increase rate by 17% when the magnetic field was increased from 0 to 750 G.

This study reports the in-depth investigation of the thermophysical properties and thermal reliability of caprylic acid-stearyl alcohol (CA-SA) eutectic phase change material (PCM) for cooling applications. The phase diagram of CA-SA showed a eutectic point at a 90:10 molar ratio. The onset melting/freezing temperature and latent heat of fusion of caprylic acid-stearyl alcohol from the differential scanning calorimetry (DSC) were 11.4 °C/11.8 °C and 154.4/150.5 J/g, respec-tively. The thermal conductivity for the prepared eutectic PCM in the solid phase was 0.267 W/m.K (0 °C), whereas, in the liquid phase, it was 0.165 W/m.K (20 °C). In addition, the maximum relative percentage difference (RPD) marked at the end of 200 thermal cycles was 5.2% for onset melting temperature and 18.9% for phase change enthalpy. The Fourier transform infrared spectroscopy (FT-IR) result shows that the eutectic PCM holds good chemical stability. Corrosion tests showed that caprylic acid-stearyl alcohol could be a potential candidate for cold thermal energy storage applications.

The surging energy requirements and greenhouse gas (GHG) emission have directed the research towards the utilization of renewable energy sources especially solar energy. Most of the energy part in domestic and commercial consumption is utilized for air heating and drying which can be improved significantly by utilizing solar air heating applications. The main drawback associated with the solar air heating system (SAHS) is the fluctuation in the availability of solar radiations which can be mitigated by a greater extent with the help of thermal storage. Phase change materials (PCMs) are generally utilized for latent heat storage. The present study reviews the various PCMs utilized in thermal storage with SAHS. Numerous types of PCM materials, their properties and applications in solar air heating system have been reviewed. Heat transfer characteristics enhancement techniques like encapsulation, extended surfaces and conductive particle dispersion have also been studied. The air conditioning demands in the future could be significantly mitigated by utilizing these materials.

One of the most effective techniques that is used for energy wastage in buildings is heat insulation. It is possible due to this application to minimize the fuel quantity and accordingly tolerate toxic emissions by finding the optimum point that gives the maximum efficiency. This study was conducted for Jaipur province in Indian climate geography. Climatic characteristics of the region are Mid-Latitude Steppe and Desert Climate (Bsh). Energy need and heat losses in exterior wall were determined by accepting cooling degree day value as T>24°C. Optimum insulation thickness, payback period, annual return and annual return rate for XPS and EPS of two different insulating materials respectively are 0.0383-0.0731, 2.35-1.79, 10.95-12.92, 46.84-37.25.

This article focuses on the investigation of thermo-physical properties of lauryl alcohol, an organic fatty alcohol as a potential phase change material for thermal management in buildings. The thermal properties of lauryl alcohol over repeated accelerated thermal cycles were investigated by using differential scanning calorimetry. The chemical stability was studied using Fourier transform infrared spectroscopy. The commonly used heat exchanger construction materials such as copper, aluminium and stainless steel 316 were subjected to corrosion analysis and the results were presented. Further, the experimental discharge characteristics of lauryl alcohol as phase change material in a prototype test chamber with internal and external load were performed. In case of internal load condition, the internal chamber air temperature is a key factor for the temperature drop in the chamber and in case of external load condition, better results are obtained in experiments conducted with high inlet temperature and low inlet air velocity.

Energy storage is recognized as being of pivotal importance in development of sustainable buildings. This research focuses on exploration of a novel cold thermal energy storage material that effectively imparts thermal comfort in buildings. The newly identified eutectic phase change material (PCM) comprises of lauryl alcohol and stearyl alcohol in the composition 90:10. For enabling its use in various cooling applications, the thermophysical properties of the identified PCM requires careful examination. By Differential Scanning Calorimetry analysis, the melting point and latent heat of fusion of the new eutectic are 22.93 °C and 205.79 J g − 1, fitting the intended application. Thermal conductivity studies, thermogravimetric analysis and thermal cycling tests ascertain the material competency. The new eutectic also accounts for successful performance during its charge-discharge studies in a thermal energy storage integrated prototype test chamber. It is concluded that the developed PCM is an able material for thermal energy storage and indoor comfort in buildings.

Phase change material (PCM) based energy storage technology is a promising solution to conserve thermal energy. This work involves studies on thermophysical properties of butyl stearate as PCM for thermal comfort application and its corrosion compatibility with commonly used heat exchanger construction materials. The thermophysical properties of butyl stearate is studied using differential scanning calorimetry and the result shows that the peak melting and freezing temperatures are 18.64°C and 13.28°C, respectively. The latent heat of melting and freezing are 120.59 Jg−1 and 120.70 Jg−1, respectively. The accelerated thermal cycling test reveals that butyl stearate is stable upto 1000 repeated thermal cycles. The thermogravimetric studies and Fourier transform infrared spectroscopy confirm that butyl stearate is thermally and chemically stable. The results of corrosion test provide information about selection of construction materials for heat exchanger and encapsulation in real-time application. Butyl stearate is a potential PCM which can be used in thermal energy storage system for thermal comfort application.

In this article, a novel concept of the latent heat thermal energy storage system combined with the conventional cooling system is proposed for the application of indoor thermal comfort. Lauryl alcohol with a melting point of 22-25°C is selected as phase change materials (PCM) for the study. From the results of experiment conducted with different mass of PCM, there is no change in temperature drop achieved while increasing PCM mass but there is increase in discharge time. The average air temperature in bottom chamber is maintained at 26°C which is in thermal comfort range throughout the experiment. For the experiments with different inlet air temperatures, higher drop in top chamber outlet air temperature is achieved for higher inlet temperatures. The temperature of the room can bring down to human thermal comfort range with a minimum duration of time with the proposed system irrespective of initial room temperature. The proposed system helps to maintain the buildings in human thermal comfort range with less-energy consumption when the conventional air-conditioning system is not in operation which in turn decreases the major energy consumption by the building sector through other auxiliary energy source.

This work is about the preparation and studies on lauric acid- myristyl alcohol solid-to-liquid binary eutectic phase change material used for indoor thermal comfort. The binary eutectic mixture consisting of lauric acid (40%) and myristyl alcohol (60%) is prepared, and its thermal properties are investigated. From the differential scanning calorimetric results, it is evidenced that the developed phase change material (PCM) possesses a melting temperature and a latent heat of 21.3°C and 151.5 kJ kg−1, respectively. The freezing temperature and latent heat are 19.9°C and 151.6 kJ kg−1, respectively. The Fourier transform infrared (FT-IR) spectroscopy results confirm that the eutectic PCM is chemically stable. The accelerated thermal cycling test proves that the developed eutectic PCM is thermally stable upto 1000 thermal cycles. The thermogravimetric results revealed that the degradation of developed eutectic PCM occurs at a temperature of 165°C, which is higher than the application temperature. Also, the results of corrosion test with the construction materials such as Cu, Al, and stainless steel are presented with necessary recommendations for using it in real-time applications. The developed novel eutectic PCM has significant potential for using it in an indoor thermal comfort application.

This study focuses on the preparation, thermophysical properties, and corrosion analysis of a stable capric acid/cetyl alcohol eutectic phase-change material (PCM) for application in the thermal comfort of buildings. Differential scanning calorimetry is used to investigate the thermal properties of the prepared eutectic PCM, and the results show that the eutectic composition of 70 % capric acid and 30 % cetyl alcohol was suitable for low-temperature thermal energy storage as it had melting and freezing temperatures of 22.89 and 11.97 °C, respectively. The latent heats of melting and freezing of the eutectic PCM are 144.92 and 145.85 J g−1, respectively. The changes in the melting point and latent heat of the eutectic mixtures over continuous charging/discharging cycles are presented. The accelerated thermal cycling test and FTIR spectra show that the prepared eutectic PCM has a good thermal stability over 1000 thermal cycles. Moreover, corrosion compatibility tests for Cu, Al, and stainless steel 316 samples with the prepared eutectic PCM are discussed, and recommendations for the use of the PCM in the operational environment are presented.

This paper gives a comprehensive review on recent developments and the previous research studies on cold thermal energy storage using phase change materials (PCM). Such commercially available PCMs having the potential to be used as material for cold energy storage are categorised and listed with their melting point and latent heat of fusion. Also techniques for improving the thermo-physical properties of PCM such as heat transfer enhancement, encapsulation, inclusion of nanostructures and shape stabilization are reviewed. The effect of stability due to the corrosion of construction materials is also reported. Finally, different applications where the PCM can be employed for cold energy storage such as free cooling of building, air-conditioning, refrigerated trucks and cold packing are discussed.