Concentrated photovoltaic thermal systems:A component-by-component view on the developments in the design, heat transfer medium and applications

The need of the hour in present world scenario is to reduce the emission of greenhouse gases and environmental pollution whilst satisfying the world energy demands. The most promising and readily available source of energy over the whole world is solar energy. One of the ways of taping this energy into useful energy is using Concentrated Photovoltaic Thermal systems. The paper presents the advanced comprehensive review on the design components of Concentrated Photovoltaic Thermal, heat transfer medium, recent application area such as Tissue Dyeing, domestic hot water, Organic Rankine Cycle, and the economic aspect of the Concentrated Photovoltaic Thermal system. Furthermore, the review paper simplifies the classification into two systems namely thermally coupled and thermally decoupled systems. Concentrated Photovoltaic Thermal shows potential to deliver better gains compared to Concentrated Photovoltaic, Photovoltaic and Photovoltaic Thermal. But matching the different components like the heat transfer component and the medium for specific use is an area that requires research. Therefore, this review concentrates more on the advantages and limitations of using different heat transfer components and heat transfer medium. The benefits of this paper would be the understanding of the components of the heat transport system like fins, microchannel, storage tank and underground heat exchangers and the fluid used in the Concentrated Photovoltaic Thermal integrated system like water, air, nanofluids, Phase Change Materials. It is found that the heat transfer device performance is limited due to its large area, thermal losses, mirror effect on the thermal and electrical efficiencies, and the temperature difference between the sink and device. Likewise, the performance of the heat transfer fluid is dependent on the mass flow rate, thermal mass, viscosity, density, time and the required temperature. Finally, for economic feasibility of the Concentrated Photovoltaic Thermal system requires the need for a grid connected system with properly sized system with feed-in-tariff and carbon incentives. Furthermore, the recommendation for heat transfer device, medium and economic aspect is also presented. However, more experimental research is required to further understand the compatibility of each components with Concentrating Photovoltaic Thermal System as presented in way forward

Shape stable composite phase change material with improved thermal conductivity for electrical-to-thermal energy conversion and storage

Limited thermal conductivity and leakage of phase change material (PCM) are among the most challenging obstacles that impede their effective applications in real-world scenarios. This study focussed on enhancing the thermal conductivity (TC), address leakage issues and incorporate thermoelectric conversion capabilities by using a single multifunctional scaffold. The shape stable PCM (ss-PCM) composite has been prepared using medium temperature range (~46 °C) commercial grade paraffin wax (PW) as organic PCM while expanded graphite (EG) as an encapsulating scaffold. The composite was prepared using vacuum impregnation method, incorporating various weight percentages (wt.%) of EG. In particular, the three wt.% of EG that has been used to encapsulate PCM are 5 % (ss-PCM1), 10 % (ss-PCM2) and 15 % (ss-PCM3). Then the composite was evaluated for its thermal stability, potential chemical interactions, leakage prevention, optical properties, thermal conductivity and thermo-electric conversion capability. Results revealed that the incorporation of 15 wt% EG in PCM (ss-PCM3) demonstrated no traces of leakage even after heating the composite at 60 °C. In addition, a significant increment of 447 % in thermal conductivity and 98 % in light absorbance has been observed. However, the composite showed a slight decrement of 13.83 % in latent heat related to base PCM. Finally, ss-PCM3 was put through to 500 heating-cooling cycles to evaluate its reliability and potential defects due to thermal fatigue. The characterization results of the composite were in close agreement before and after the thermal cycling, indicating its potential for practical applications. The electro-thermal conversion measurement findings indicate that the ss-PCM3 can achieve a conversion ability of 61.89 % when operated at 4.8 V. Several potential applications for this composite include energy-efficient buildings, infrared thermal concealment, solar energy utilization, and heat insulation

Thermal performance and corrosion resistance analysis of inorganic eutectic phase change material with one dimensional carbon nanomaterial

The inherent thermal characteristics, supercooling phenomenon, and corrosion issues associated with salt hydrate phase change materials (PCMs) limit their practical applications. In this research work, we report a newly formulated eutectic salt hydrate PCM using a) sodium sulphate decahydrate (SSD) & b) sodium phosphate dibasic dodecahydrate (SPDD); with a focus on customizing its properties to enhance its suitability for low temperature thermal regulation (achieving a melting point of 27.8 °C and a high heat storage capacity of 215 J/g). Additionally, we have successfully reduced the degree of supercooling and introduced corrosion resistant properties to this PCM. To enhance both the thermal energy transfer rate and optical absorbance of the eutectic PCM, we have incorporated one-dimensional (1D) multiwall carbon nanotube (MWCNT) at various weight fractions, extending up to 0.9 %, utilizing a two-step method. The dispersion and chemical stability of SSD/SPDD + MWCNT nanocomposite are verified through the morphological visual and spectral peaks obtained in Fourier transfer infrared spectroscopy. Additionally, studies evaluating the optical and thermal property reveal a substantial 500 % increase in absorbance, a notable 77.9 % reduction in transmissibility, a thermal conductivity increase from 0.464 W/m⋅K to 0.742 W/m⋅K (reflecting a 59.9 % increment), and the retention of a consistent melting enthalpy of 218.6 J/g. This stability is attributed to the intermolecular interaction with MWCNT. Similary, the degree of supercooling (ΔT s) for the SSD/SPDD EPCM containing MWCNT decreased to 2.2 °C from 16.5 °C, marking an 86 % reduction compared to the pure eutectic salt solution. Furthermore, this composite demonstrated enhanced thermal and chemical stability throughout 200 thermal cycles. Auxiliary ANSYS simulation, with transient boundary condition, are provided to analyze the heat transfer interactions between the thermic fluid and the newly developed PCM when integrated into a thermal regulation system. Subsequently, a corrosion analysis of the developed eutectic PCM and the nanocomposite eutectic PCM exhibits a corrosion rate of 0.018 mpy, well below the permissible level (<5mpy). The insights gained from the development of this nanocomposite PCM offer valuable guidance for the design and creation of tailored eutectic PCM for low-temperature thermal regulation systems, resulting in significant energy savings

Thermal conductivity and Thermal properties enhancement of Paraffin/Titanium Oxide based Nano enhanced Phase change materials for Energy storage

The Latent heat storage (LHS) based on phase change materials (PCMs) has a critical part to demonstration in preserving and efficiently utilizing energy, resolving demand-supply mismatches, and boosting the efficiency of energy systems. However, they have a low thermal performance inherent in it because the low thermal conductivity (TC) of PCMs. Paraffin organic PCMs have several advantages such as higher LHS, nontoxic, abundant in nature and inexpensive, whereas TiO2 nanoparticle is type of hydrophilic group having tendency to improve TC. In this research TiO2 in different concentration (0.1, 0.5, 1, and 2 wt percent) with surfactant sodium dodecyl benzene sulphonate (SDBS) added into Paraffin RT44 HC PCM using two step techniques, and the thermophysical properties were broadly discussed. Thermogravimetric analyzer (TGA), Fourier transform infrared spectroscopy (FT-IR) and Thermal property analyzer (TEMPOS) were used for the characterization of prepared composite nano-enhanced phase change materials (NePCM). Additionally, the effect of nanoparticles on TC was investigated. The highest TC was obtained with PW/TiO2-1.0 by an increment of 86.36% as related with base PW. The FTIR spectrum of the composite PW/TiO2 confirmed no interaction between PW and TiO2, resulting in a more chemical stable composite. The addition of TiO2 to PW enhance the degrading temperature 10 C by making it more thermal stable. Grounded on the results it can be concluded that the developed composite is suitable for thermal energy storage (TES), photovoltaic thermal (PVT) systems, and hot water applications

Investigation of thermal performance and chemical stability of graphene enhanced phase change material for thermal energy storage

Phase change materials (PCMs) have received widespread thermal energy storage (TES) and release properties due to their unique characteristics. However, the PCMs suffer from poor thermal conductivity, resulting in the least thermal performance and heat transfer characteristics. This research focused on enhancing the heat transfer and storage characteristics by developing an organic paraffin wax composite by dispersing highly conductive graphene powder using a two-step technique. The results show that the developed nano enhanced PCM significantly improves the thermal conductivity by 72.2% at 0.6 wt% of graphene powder. Furthermore, the Fourier transform infrared spectrum shows there is no additional peak observed, means physically and chemically stable, and the reduced light transmission capability was enhanced by 32.0% than pure PCM. Due to its extreme characteristics, the developed PCM is an outstanding material for medium temperature solar thermal energy storage applications

Effect of surfactant on functionalized multi-walled carbon nano tubes enhanced salt hydrate phase change material

Phase change materials (PCMs) are effective thermal energy storage materials; however, their low thermal conductivity nature tends to affect heat storage performance. Salt hydrate being inexpensive, incombustible and ensuring high phase change enthalpy, are highly attractive for energy storage. The potential of multi-walled carbon nanotubes (MWCNTs) in improving the thermophysical properties of salt hydrate PCMs makes it a hotspot of current research. Therefore, in this research article, MWCNTs and functionalized multi-walled carbon nanotubes (FMWCNTs) nanoparticles were dispersed with inorganic salt hydrate at different concentrations (0.3, 0.5, and 1.0 wt%), in the presence and absence of surfactant. The role of surfactant with salt hydrate PCM has been discussed extensively. The results obtained have ensured an enhancement in melting enthalpy of prepared composites by 4.92 %, and 28.5 % for 0.5 wt% MWCNT dispersed PCM (SHM0.5), and 0.5 wt% FMWCNT dispersed PCM (SHF0.5), respectively. Furthermore, the maximum thermal conductivity was enhanced by 50.0 % and 84.78 % for 0.5 wt% MWCNT dispersed PCM with surfactant (SHMS0.5), and SHF0.5 respectively, compared to salt hydrate PCM. From the improvement in thermal conductivity, light absorptance, thermal stability, latent heat, and chemical stability, it is evident that the prepared nanocomposite is a potential candidate for solar thermal energy storage applicatio

Development of phase change materials based microencapsulated technology for buildings: A review

Thermal energy storage (TES) systems using phase change material (PCM) have been recognized as one of the most advanced energy technologies in enhancing the energy efficiency and sustainability of buildings. Now the research is focus on suitable method to incorporate PCMs with building. There are several methods to use phase change materials (PCMs) in thermal energy storage (TES) for different applications. Microencapsulation is one of the well known and advanced technologies for better utilization of PCMs with building parts, such as, wall, roof and floor besides, within the building materials. Phase change materials based microencapsulation for latent heat thermal storage (LHTS) systems for building application offers a challenging option to be employed as effective thermal energy storage and a retrieval device. Since the particular interest in using microencapsulation PCMs for concrete and wall/wallboards, the specific research efforts on both subjects are reviewed separately. This paper presents an overview of the previous research work on microencapsulation technology for thermal energy storage incorporating the phase change materials (PCMs) in the building applications, along with few useful conclusive remarks concluded from the available literature.Phase change material Microencapsulation technology Thermal energy storage systems Building applications

Review on thermal energy storage with phase change materials and applications

The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. PCMs have been widely used in latent heat thermal-storage systems for heat pumps, solar engineering, and spacecraft thermal control applications. The uses of PCMs for heating and cooling applications for buildings have been investigated within the past decade. There are large numbers of PCMs that melt and solidify at a wide range of temperatures, making them attractive in a number of applications. This paper also summarizes the investigation and analysis of the available thermal energy storage systems incorporating PCMs for use in different applications.Thermal energy storage systems Phase change material Solar energy Latent heat Melt fraction

Advancements in foam-based phase change materials : Unveiling leakage control, enhanced thermal conductivity, and promising applications

In recent years, phase change materials (PCMs) have attracted considerable interest due to their capacity to store and release enormous energy during phase transitions. However, low thermal conductivity and leakage are significant obstacles that hinder the efficacy of PCMs. Foams and porous matrices have been investigated as potential solutions to the leakage problem in PCMs. This review examines the use of foam to improve the thermal energy storage performance of PCMs. The primary objective of this paper is to unveil the leakage control using foams and discuss the effect on the thermophysical properties of foam-based PCMs. To achieve this objective, we have reviewed previous research in this area, established the research's rationale, and filled any voids in the literature. The paper examines the utilization of carbon-based and metallic foams for PCMs at varying temperatures. It evaluates the methodologies used to evaluate the efficacy of PCMs with foam reinforcement. Key findings include the significant enhancement in thermo-physical properties of PCM performance due to the use of foam and the potential applications of these materials in various fields, including thermal management of batteries, heating and cooling of buildings, smart textiles and electronic heat sinks. The study also summarizes the foams and other porous matrices to compare their performance with PCM. Foam-based PCMs prove to be a strong candidate by solving the leakage issue in PCMs without compromising their thermophysical properties