Selection Of Phase Change Materials Research Articles

Role of Phase Change Materials Containing Carbonized Rice husks on the Roof-Surface and Indoor Temperatures for Cool Roof System Application.

This study researches the effect of phase change materials (PCMs) containing carbonized rice husks (CRHs) in wood plastic composites (WPCs) as roof finishing materials on roof-surface and indoor temperatures. A cool roof miniature model was prepared, and measurements were taken using three fixed temperatures of 30 to 32 °C, 35 to 37 °C, and 40 to 42 °C. Sodium sulfate decahydrate (Na2SO4·10H2O) and paraffin wax were selected as the PCMs. CRHs were used as additives to improve the thermal conductivities of the PCMs. At lower fixed temperatures such as 30 to 32 °C and 35 to 37 °C, the rates of increase of the surface temperatures of roofs containing CRHs with Na2SO4·10H2O, and paraffin wax, were observed to gradually decrease compared to those of the roofs without PCMs. The indoor temperatures for the above-mentioned PCMs containing CRHs were maintained to be lower than those of the indoors without PCMs. Additionally, as the CRH content in the PCM increased, the rates of increase of the roof-surface and indoor temperatures decreased due to a faster roof heat absorption by PCMs through the improved thermal conductivity of CRHs. However, under higher artificial temperatures such as 40 to 42 °C, Na2SO4·10H2O with CRHs exhibited no effect due to being out of latent heat range of Na2SO4·H2O. For paraffin wax, as CRH content increased, their roof- surface and indoor temperatures decreased. Especially, the surface temperature of the roof containing paraffin contained 5 wt.% CRHs reduced by 11 °C, and its indoor temperature dropped to 26.4 °C. The thermal conductivity of PCM was enhanced by the addition of CRHs. A suitable PCM selection in each location can result in the reduction of the roof-surface and indoor temperatures.

A phase change material selection using the interval-valued target-based BWM-CoCoMULTIMOORA approach: A case-study on interior building applications

The move towards sustainable development and energy efficient solutions in the built environment has led to develop innovative solutions, particularly in the area of indoor environmental comfort in buildings. Phase change materials (PCMs) are a potential approach to target building energy use reduction. PCMs are smart materials that have been commercialized and used in buildings for effective regulation of surface and indoor air temperature fluctuations and peak energy reductions. Appropriate PCM selection is the critical step in PCM system design that determines the full effectiveness and applicability of PCM integrated building applications. Optimal selection of PCMs can be effectively executed with the support of multiple attribute decision making (MADM) approaches. Although, the traditional MADM methods have usually focused on beneficial and non-beneficial attributes, in real-world and practical problems, decision-makers tend to determine the rank of an optimal alternative based on the target values of their attributes. In response to the knowledge gap of an existing practical and functional PCM selection solution, this study proposed a hybrid and novel target-based MADM approach that combines the best-worst method (BWM) with COmbined COmpromise SOlution (CoCoSo) and multi-objective optimization of ratio analysis plus the full multiplicative form (MULTIMOORA) with an interval-valued structure called the IV-T-BWM-CoCoMULTIMOORA approach. A case study is examined to select the optimal PCM for interior building surface applications based on a case-specific construction project in Toronto, Canada. Two separate scenarios are considered, one based on thermophysical specifications and one based on managerial preferences. The connection between both technical and managerial criteria was demonstrated to clearly affect the decision-making process to take into account both thermophysical properties of PCM alternatives in the context of risk factors and design considerations. Nevertheless, the influence of the technical parameters was shown to be dominant in the final selection of the best case scenario.

Thermophysical properties of KCl-NaF reciprocal eutectic by artificial neural network prediction and experimental measurements

Fluoride and chloride reciprocal salts are potential novel media with suitable working temperature and high latent heat for next-generation solar power. A back propagation (BP) artificial neural network (ANN) algorithm was developed based on the known data of salts. The composition and melting point of two unknown binary fluoride and chloride reciprocal salts were predicted by the trained ANN model. The predicted composition and melting point of the reciprocal salts were verified by experimental tests. The predicted results of composition are in good agreement with the experimental values, and the predicted errors of the melting point are less than 1.5%. The melting point and fusion enthalpy of KCl-NaF reciprocal eutectic salt are 648 ± 2 °C and 365 ± 5 J/g, respectively. The thermal stability of this reciprocal eutectic salt is very good and the weight loss is still less than 3.0% even up to 800 °C. The good performance of KCl-NaF reciprocal eutectic salt at high temperatures suggest that it can be a good candidate for thermal energy storage systems with supercritical CO2 cycles. The ANN is an effective method to prediction composition and properties of molten salts, this method is expected to a quick method for design and selection of phase change material for the high temperature latent heat energy storage systems.

Selection of phase change materials, metal foams and geometries for improving metal hydride performance

This paper reports the numerical investigation of the effect of different phase change materials (PCMs) on the metal hydride (MH) behaviour in a reactor bed during the absorption process. The feasibility of integrating metal foams (MFs) into the phase change materials to improve the hydrogen storage performance of the system was also evaluated. A two-dimensional model for a LaNi5 hydride reactor equipped with different phase change materials has been developed. The selection of five different PCMs having a high latent heat of fusion and a range of melting temperatures were investigated. In addition, the effect of the mass and volume of the different PCMs on the hydrogen performance of the MH reactor was studied. It was found that LiNO3·3H2O PCM shown better performance than the other PCMs, its loading time is faster, and its mass within the reactor is enough to absorb the total heat generated from the MH during hydrogenation. Three different metals foam with three different porosities were integrated into the most suitable PCM with the appropriate dimension of a cylindrical reactor that shows the optimum performance. The obtained results indicated that the integration of the metal foams into the PCM show better heat transfer performance than the case of MH-PCM without metal foams. Two different configurations cylindrical and spherical MH reactors were investigated. The obtained results indicated that the two configurations have very similar behaviours. So, both configurations are good for the hydriding process within an MH reactor.

Selection of phase change material for improved performance of Trombe wall systems using the entropy weight and TOPSIS methodology

The past decade has witnessed a lot of technological advancement towards the use of renewable and sustainable energy resources, these efforts are geared towards mitigating the effect of climate change and to make our environment safe and habitable. Today, buildings account for over 40% of the world's total energy consumption. Thermal energy storage in buildings contributes significantly to the reduction of building energy demand by releasing its stored energy when the demand arises. Trombe walls are used for thermal energy storage and delivery in buildings and thus regulates the rooms ambient temperature. A lot of studies have considered the use of phase change materials for latent heat thermal energy storage in Trombe walls in order to improve its performance. The selection of phase change materials for optimum Trombe wall performance was considered in this article, the weights of the various criteria were determined using the entropy weight method while the various alternative phase change materials were ranked using the technique for order preference by similarity to ideal solution (TOPSIS) methodology. The four criteria considered were the heat of fusion, thermal conductivity, density, and cost. A total of eleven commonly available phase change materials were considered in this study, with phase change temperatures within the range 18 C–28 C which corresponds to the average temperature range for human comfort. The result had the thermal conductivity was assigned the highest weight of 72.12% while the eutectic combination of capric acid and palmitic acid ranked the best at 95.1% for Trombe wall application.

Microstructure and thermal properties of Bi-Sn eutectic alloy

AbstractAlloys based on Sn and Bi are considered to be one of the best soft lead-free solders due to their low melting temperature and low price. In addition, Bi-Sn alloy with a eutectic composition represents a promising candidate as a metallic phase change material (PCM) for use in the field of thermal energy storage (TES). The accurate knowledge of microstructural and thermophysical properties such as the latent heat of melting, thermal conductivity, specific heat capacity is of crucial importance for PCM selection. Thus, the aim of the current study has been to determine the microstructure, latent heat of melting and thermal conductivity of a eutectic alloy from the binary Bi-Sn system.

Guidelines for phase change material selection based on a holistic system model

Concentrating solar power (CSP) has potential to increase the amount of renewable energy on electric grids and reduce global carbon emissions, in particular because of its capability to incorporate inexpensive thermal energy storage. To realize this potential, development of latent heat storage with phase change materials (PCMs) is attractive because of its high energy density and low material cost. Research in this area has identified many promising materials, and has developed effective storage system designs that could be used to deploy PCMs. However, the field has lacked a rigorous methodology to select the optimal material for a particular CSP system. To address this need, here we present a holistic model that evaluates all important influences of PCM properties on the performance and cost of an entire CSP plant. We apply this model to over 100 of the most widely considered candidate materials, including both salts and metals. We quantify the relative value of each PCM property, and identify leading materials for application in CSP systems. This method and our results may aid future efforts to develop latent heat storage by providing a more informed view of how material selection impacts an entire CSP system.

Review of latent thermal energy storage systems for solar air‐conditioning systems

Solar air-conditioning is an important approach to satisfy the high demand for cooling given the global energy situation. The application of phase-change materials (PCMs) in a thermal storage system is a way to address temporary power problems of solar air-conditioning systems. This paper reviews the selection, strengthening, and application of PCMs and containers in latent thermal storage system for solar air-conditioning systems. The optimization of PCM container geometry is summarized and analyzed. The hybrid enhancement methods for PCMs and containers, and the cost assessment of latent thermal storage system are discussed. The more effective heat transfer enhancement using PCMs was found to mainly involve micro-nano additives. Combinations of fins and nanoadditives, nanoparticles and metal foam are the main hybrid strengthening method. However, the thermal storage effect of hybrid strengthening is not necessarily better than single strengthening. At the same time, the latent thermal storage unit has less application in the field of solar air-conditioning systems, especially regarding heat recovery, because of its cost and thermal storage time. The integration of latent thermal storage units and solar air-conditioning components, economic analysis of improvement technology, and quantitative studies on hybrid improvement are potential research directions in the future.

Multiple-Criteria Decision Analysis and characterisation of phase change materials for waste heat recovery at high temperature for sustainable energy-intensive industry

A latent heat storage system based on Phase Change Materials (PCMs) is proposed to increase the energy and environmental efficiency by recovering and storing waste heat from combustion gases or other surplus sources at in the energy-intensive industries (EII), currently unused. The final configuration design is specifically adapted to the plant operational requirements, by means of a methodology combining the search of the best conceptual design and a proper selection of core PCMs. To that end, a selection of suitable PCM is carried out by using characterisation techniques and thermal stability testing. Furthermore, relevant key factors are weighted by an in-house Multiple-Criteria Decision Analysis (MCDA) to define the most promising design options to be implemented in two plants belonging to the EII sector. For the ceramic sector, the design resulted in a shell-and-tube system with 1188 kg of a PCM melting at 885 °C and encapsulated in double concentric tubes, involving a storage capacity of 227 MJ. Similarly, 1606 kg of PCM, whose phase-change temperature is 509 °C, is selected for the steel sector providing a PCM-TES system capable to store 420 MJ.

Augmenting the productivity of solar still using multiple PCMs as heat energy storage

Abstract In recent years, several research studies were conducted to enhance the productivity of solar stills. One of the approaches was the integration of latent heat energy storage mediums (phase change materials (PCM)) in the conventional solar stills to extend the water yield ability after the sunshine hours. Though several studies were conducted in this research area, none of the studies analyzed and reported the time of day at which the PCM start to release the stored latent heat, especially in the case of use of multiple PCMs. The present study is an experimental investigation that compare the thermal performance of three same-sized passive solar stills, i.e., conventional solar still (Still 1), still with single phase change material (Still II), still with two phase change materials (Solar III). The two PCMs used in still III are chosen in such a way that both the PCMs have almost same latent heat storage capacity, but different phase change temperature range. PCM1 and PCM2 used in solar still III have the phase change temperature (PCT) range of 58.03 °C–64.5 °C and 53.05 °C–62 °C, respectively. The experiments were conducted for the climatic conditions of Chennai, India during the month of February to May. The major inference from the experiments conducted is that, when multiple PCMs are employed in a still, selection of PCM with appropriate PCT range is very important. PCM1 should start discharging the stored latent heat energy stored once the solar radiation gets diminishing and PCM2 should start to release the heat when PCM1 has almost discharged the entire stored energy. By this way, the time of yield can be prolonged. In the results, the thermal performance of Still I, II and III was analyzed in terms of hourly yield per day and exergy efficiency. The yield of Still I was 3.680 L/m2/day while the yield of Still II and III were 4.020 L/m2/day and 4.400 L/m2/day, respectively. The exergy efficiency of still I, II and III were found to be 3.92%, 3.23% and 3.52%, respectively.

Review on performance assessment of phase change materials in buildings for thermal management through passive approach

Abstract Latent heat energy storage (LHES) systems using phase change materials (PCMs) are well known for its excellent thermal energy storage and release during melting and solidifications respectively. PCMs can be efficiently deployed in applications where significant temperature difference exists in the system for intermittent thermal energy storage. Several research contributions has been made on integrating PCMs in buildings for thermal management, as it enhances building thermal inertia, reduces maximum heat flux, shifts peak energy demand, reduces temperature fluctuations of air, etc., owing to its isothermal behavior and high energy storage density during phase change. Results of several research articles reveal that incorporation of PCM in buildings could significantly improve indoor comfort conditions and reduce energy demand of Heating ventilation and air conditioning (HVAC) systems, provided appropriate PCM selection, encapsulation methods, location deployed etc. This review paper is devoted to elucidate various facts attributing PCM integration in buildings for thermal management through passive approach. The facts includes performance of PCMs in buildings in terms of heat gain reduction, temperature attenuation, peak energy demand shifting and energy saving potential, encapsulation deployed, are discussed and presented in order to expedite the interpretation for future researchers, who took their research work in the field of building thermal energy management.

Selection of phase change material for solar thermal storage application: a comparative study

The study of five paraffin waxes and wood resin was carried out to investigate their thermo-physical properties. The investigation aimed at selection of a phase change material (PCM), for its potential use as a thermal energy reservoir (TER) in a fabricated solar dryer. Differential scanning calorimeter was used to determine the melting point, solidification point, latent heat of fusion and solidification of these PCM. The T-history analysis was carried out to determine the effective thermal conductivity and specific heat in liquid and solid states. Bulk density of these PCMs was determined using standard pycnometer method. A comparative analysis was done for the selection, and PW1 was selected among the paraffin waxes, while wood resin was rejected. The selected PCM was used in the flat plate collector of solar dryer to identify the thermal zones and to validate its capability as a TER. Maximum temperature achieved at outlet of flat plate collector was 50 °C. The temperature profile built in different zones was determined with and without using PCM. It was found that after 18:00 IST evening, the average flat plate collector chamber temperature with PCM PW1 was found to be 23.5% higher than that without using PCM.

Analysis of phase change materials (PCM) for building wallboards based on the effect of environment

One of the greatest global challenge and an indispensable requirement for sustainable development in the building sector is the reduction of greenhouse gas emissions and energy consumption. In this regards, it is necessary the development and promotion of efficient, affordable, and high impact technologies, systems, and practices. For this purpose, new technologies as phase change materials (PCM) is being studied to improve the energy efficiency and reduce energy usage in buildings.This research aims to analyze the selection of PCM for building wallboards and roofs by comparison between multi-criteria decision methods (MCDM) and Building Energy Simulations (BES). For this purpose, a reference generic social dwelling designed in Ecuador to shelter four people in a space of 36 m2 has been chosen to perform the study.The MCDM COPRAS-G, TOPSIS and VIKOR are considered to accurately rank PCM alternatives, taking in consideration different material selection criteria. Moreover, BES are performed to: (a) further contrast the MCDM ranking of PCM and (b) numerically assess the thermal behavior and estimate the energy consumption with the incorporation of the PCMs.The results found discrepancies between the MCDM and BES, demonstrating the importance that the environment variables play to appropriately assess the performance of PCM.

Experimental investigation of heat transfer characteristics in a vertical multi-tube latent heat thermal energy storage system

A vertical multi-tube thermal energy storage system using commercial phase change material (PCM) RT60 has been experimentally investigated. The selection of PCM and experimental rig configurations seek to be suitable to serve as a household thermal energy storage application for the solar energy application. PCM is filled at the annulus of the shell of the cylindrical container and the tubes while heat transfer fluid (HTF) is circulated inside tube to deliver or retrieve thermal energy to or from PCM. Five HTF tubes are configured to achieve heat transfer enhancement in this vertical latent heat thermal energy storage system. Thermocouples are installed at four horizontal cross-sections of the storage unit and at every cross-section thermocouples are positioned at different radial and angular coordinates to capture the transient temperature changes of PCM during the charging and discharging processes. HTF inlet temperature was set at 80 °C in the charging process and 10 °C in the discharging process. The same HTF volume flow rate of 20 L/min was applied in the consecutive charging and discharging processes. The comparative analysis of PCM temperature measurements along the axial, radial and angular directions was conducted. The experimental results showed that natural convection-controlled heat transfer during the charging process, while PCM solidified faster at the bottom liquid PCM region during the early stage of discharging, afterwards conduction dominated heat transfer mode. The analytical study and experimental data stated that the arrangement and positions of HTF tubes have a notable effect on the thermal response of the latent heat thermal energy storage system during the charging and discharging processes.

Freeze-thaw performance of phase change material (PCM) incorporated pavement subgrade soil

Phase Change Materials (PCMs) can store and release large amounts of energy in the form of latent heat during their phase changes, which could be utilized in controlling the freeze-thaw impact on pavement foundation systems. Untreated, and Class C fly ash-treated loess soil amended with three different dosages of paraffin-based liquid, and microencapsulated PCMs were evaluated using unconfined compression, volume change, and frost heave tests. The results of this research support the use of PCMs in controlling the freeze-thaw effect on subgrade soil. Further recommendations are provided on PCMs selection, composite type PCMs, incorporation method, and chemical stability.

A fuzzy based hybrid multi criteria decision making methodology for phase change material selection in electronics cooling system

Abstract The phase change material (PCM) selection plays a vital role in successful designing of electronic cooling systems. Since large numbers of competitive materials are available today, with each having its own characteristics, applications, advantages, and limitations, the decision for selecting a suitable PCM involves several evaluation criteria. In this article, a novel hybrid multi criteria decision making (MCDM) model is proposed for evaluating a suitable PCM for thermal management systems. The decision model consists of 10 alternative materials with eight evaluation criteria. The Fuzzy Analytical Hierarchy Process (FAHP) - integrated with Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), VlseKriterijumska Optimizacija I KompromisnoResenje (VIKOR) and Preference Ranking Organization METHod for Enrichment Evaluations (PROMETHEE) are proposed and applied in the numerical example. The results obtained from FAHP-TOPSIS, FAHP-VIKOR and FAHP- PROMETHEE are compared. The results show that RT-80 is the apt material for thermal management of power electronic devices.

Benchmarking of useful phase change materials for a building application

Nowadays, there is an increasing interest in more efficient building materials and new technologies to accomplish the objectives defined by energy policies. The combination of energy efficient building designs and integration of renewable energies makes the use of thermal energy storage (TES) necessary. Within this context, the improvement of building envelopes by the use of phase change materials (PCM) has been widely studied. The PCM selection should fulfil the requirements of the specific application. In this study, a benchmarking of PCM available in the market was performed to undertake a material selection for a specific building application. The incorporation of PCM into a radiant wall technology present several requirements with especial interest on long-term thermal stability. A complete laboratory-scale characterization has been carried out considering the following properties: temperature of phase change, specific heat capacity, thermal conductivity, and stability.

A methodological concept for phase change material selection based on multi-criteria decision making (MCDM): A case study

Phase change material (PCM) have been explored for different applications to increase the energy efficiency and economy. However, the proper PCM selection to meet given requirements generally requires that a compromise is struck between conflicting criteria. This paper attempts to extend multi-criteria decision making (MCDM) method to solve the PCM selection problem. Firstly, the comprehensive appraisal indexes model is established and the subjective and objective weight of the criteria are obtained based on the analytic hierarchy process (AHP) and entropy information method, respectively. Secondly, the optimized combination weight method is adopted to obtain the combination weight. Then, the pre-screened PCMs are ranked using technique for order performance by similarity to an ideal solution (TOPSIS). Finally, the information retrieval is employed to justify the rankings. To demonstrate the applicability of the proposed method, a problem to select the optimal PCM for ground source heat pump (GSHP) integrated with phase change thermal storage (PCTS) system is considered. The result showed that Ba(OH)2·8H2O is the best material for the given case and the GSHP integrated with PCTS system has better economic performance compared to the GSHP system, meanwhile, the proposed method is a simple and practical approach in solving the PCM selection problem.

Phase Change Material Selection for Thermal Energy Storage at High Temperature Range between 210 °C and 270 °C

The improvement of thermal energy storage systems implemented in solar technologies increases not only their performance but also their dispatchability and competitiveness in the energy market. Latent heat thermal energy storage systems are one of those storing methods. Therefore, the need of finding the best materials for each application becomes an appealing research subject. The main goal of this paper is to find suitable and economically viable materials able to work as phase change material (PCM) within the temperature range of 210–270 °C and endure daily loading and unloading processes in a system with Fresnel collector and an organic Rankine cycle (ORC). Twenty-six materials have been tested and characterized in terms of their thermophysical conditions, thermal and cycling stability, and health hazard. Two materials out of the 26 candidates achieved the last stage of the selection process. However, one of the two finalists would require an inert working atmosphere, which would highly increase the cost for the real scale application. This leads to a unique suitable material, solar salt (40 wt % KNO3/60 wt % NaNO3).

Review on Heat Transfer Enhancement of Phase Change Materials (PCMs)

For effective utilization of thermal energy storage (TES) system, selection of Phase change material (PCM) and heat transfer mechanism plays a significant role. PCMs employed in TES system undergo poor heat transfer rate due to low thermal conductivity. In order to capture larger amount of energy, it is inevitable to improve the heat transfer rate between heat transfer fluid (HTF) and PCM. The main focus of the paper is to review the previous works on heat transfer enhancement of PCMs and to develop efficient TES system. Some of the heat transfer enhancement methods namely extended surface, composite PCMs, multiple PCMs and encapsulation have been discussed. The different applications of phase change material in conserving the energy are also reviewed in this paper.