Search

Based on the Green ILC concept, an R & D program is underway to recover and utilize thermal energy emitted from the cooling water of ILC facilities. Iwate Prefecture, where the ILC Kitakami candidate site is located, is 80% mountainous, which is not suitable for online transportation of thermal energy. In order to effectively utilize the thermal energy emitted from the ILC facilities, a thermal energy circulation model suitable for such regional characteristics is required. We are aiming to commercialize an offline waste heat circulation model that utilizes an innovative adsorptive thermal storage material, "HASClay", which can utilize low-grade waste heat of 50-100°C. So far, we have developed a portable container that can hold approximately 10 kg of dry HASClay and have evaluated its heat storage and emission performance. On the other hand, one of the issues for practical use is to elucidate the mechanism of water vapor adsorption/desorption on the microstructure of "HASClay". Here, we discuss two issues: (1) a demonstration test for commercialization of a thermal energy circulation model and (2) basic research to understand the structure and adsorption/desorption mechanism of "HASClay" using synchrotron radiation. [ABSTRACT FROM AUTHOR]

A significant fraction of the energy generated for industrial and domestic applications is lost in the form of heat. Because of this, thermal-energy storage materials are receiving increasing attention as a means of storing the generated heat for later use. In this paper, a brief description is given of two types of materials used in thermal-energy-storage devices – phase change materials for latent heat storage and photoswitches for chemical energy storage. In addition, we provide a succint account of the experimental and computational tools needed to understand the microscopic mechanisms of energy storage and to facilitate the rational design of new materials. [ABSTRACT FROM AUTHOR]

Over the last ten years, there has been an increasing need for potable water as a result of fast population growth. The rural regions of Chennai endure acute water scarcity, especially in the summer season. Desalination is the most direct and efficient technique for obtaining drinkable freshwater. The widespread availability of solar energy, which is a renewable resource, offers the potential for a solar desalination process. The main objective is to harness solar energy by storing it in a heat storage substance contained within a sealed circular copper tube under pressure. The tube is thereafter submerged in a stagnant pool of salty water constructed in a spiral formation on a single plane, harnessing sun radiation throughout the whole day. Our experiments have revealed that water is a more efficient heat storage medium than paraffin wax, leading to a substantial improvement in the productivity of solar stills. We consistently observe the temperature of the still and the amount of water produced at regular intervals, and the findings are extensively analysed and debated. Although the Conventional Solar Still (CSS) and its combinations with other systems have demonstrated promise, they are limited in their ability to produce adequate amounts of freshwater. The objective of our current study is to optimise CSS techniques for freshwater production by maximising solar heat radiation and integrating Phase Change Material (PCM). Our project involves building a solar still utilising Mild Steel (MS) and 5mm untoughened glass. The dimensions of the solar still are 1000mm x 1000mm, and the collecting cover has a slope angle of 13°. [ABSTRACT FROM AUTHOR]

One of the most important uses of phase change materials (PCMs) is to conserve thermal energy, but most of these materials have a weak thermal performance because of their low thermal conductivity. To improve the thermal performance of these materials, in this study four sinusoidal fins are installed inside a latent heat storage (LHS) unit. With and without these fins, the thermal characteristics (temperature, liquid fracture and thermal energy) of a PCM (RT-42), at a 5 L/min volume flow rate and 70 °C inlet temperature of the heat transfer fluid, are numerically and experimentally investigated. The LHS unit consists of a copper tube with a 25 mm internal diameter and 2 mm thickness surrounded by a transparent hollow tube with a 75 mm internal diameter and 1 mm thickness. The fins, with a 20 mm length and 1.5 mm thickness are installed in the bottom half of the annular space of the LHS unit and which is fully filled by the PCM. The results indicate that the technique of sinusoidal fins significantly improves the thermal characteristics of the PCM. The PCM, with the fins, reaches average temperature of 41.2 °C in 100 min numerically and 110 min experimentally while, without fins, it needs for 250 min numerically and 260 min experimentally to reach the same temperature. The PCM, with the fins, melts totally (the liquid fracture equals one) during 70 min numerically and 80 min experimentally while, without fins, it needs for 200 min numerically and 210 min experimentally to melts totally. In general, the total melting time of the PCM, with the fins, is reduced by 65% numerically and 62% experimentally compared to the normal case (without fins). Also, the thermal energy gained by the PCM, with the fins, increases by about 0.83 numerically and 0.82 experimentally compared to the normal case. Through the comparison between the numerical and experimental results, an excellent agreement is found between them and the largest deviation between them is shown in the case of the liquid fracture and equals about 12%. [ABSTRACT FROM AUTHOR]

This study presents the design of refrigerated box for last mile delivery using phase change material. Since the COVID-19 pandemic, the popularity of e-commerce has been significantly increased, especially for food and fresh products. To maintain the product quality, products are kept at low temperature during delivery. This study introduces the use of phase change materials (PCMs), which can be used to maintain temperatures as low as -30 °C for longer periods compared to traditional ice packs, as a cold thermal energy storage. The objective of this study is to apply phase change materials to maintain the temperature of a refrigerated box between 4-8 °C. The phase change material used in this study is polyethylene glycol 400 (PEG 400), which has no harmful effects on human health and the environment. The material was first studied for its thermal properties using a differential scanning calorimeter (DSC) and the resulting thermal properties were then used in a preliminary numerical simulation of the material thermal responses using ANSYS Fluent. The obtained responses from the simulation were in good agreement with the experiments conducted for validation. The experiments on the refrigerated box with PEG 400 were conducted to study the performance in terms of storage time and temperature control. These results were used to elucidate the factors affecting the performance of a refrigerated box employing PCMs. [ABSTRACT FROM AUTHOR]

This paper examines selecting the most suitable materials for Sensible Energy Storage (SES) in Thermal Energy Storage (TES) systems. We focus on two key materials: graphite and magnesia (magnesium oxide). Graphite, with its remarkable ability to withstand high temperatures of up to 3500 degrees Celsius, is chosen as the SES material despite its relatively higher cost. Meanwhile, magnesia serves as a crucial thermal insulator for the SES material, enhancing heat storage effectiveness, particularly in scenarios where high-temperature heat storage materials are subject to heat exchange processes. To aid in material selection, Computational Energy Storage (CES) software systems and experimental calculations are proposed for their comprehensive analysis and evaluation of SES materials. Through these methods, optimal materials can be identified, ensuring efficient and reliable Sensible Energy Storage in Thermal Energy Storage systems. [ABSTRACT FROM AUTHOR]

The building energy consumption has increased by more than 40%, there it is needed to be managed and controlled. Phase Change Material (PCM) as Latent Heat Thermal Energy Storage (LHTES) is the solution with high heat storage and small temperature changes during the phase change process. This research focuses on the PCM injected into the wood as material building insulation. This experiment was conducted the micro characteristics of the wood after the delignification and PCM injection process as well as the rate of leakage and impregnation. The woods used are merbau, meranti, and bamboo which are local wood from Indonesia. To the delignification process to make its porous structure by alkaline pretreatment with NaOH (2.5 mol/L) and Na2SO3 (0.4 mol/L) with distilled water and the wood was immersed in a solution of H2O2 (2.5 mol/L) with distilled water. Delignification wood was injected with paraffin, bees wax, and soy wax using the vacuum impregnation method. Based on from this result that known the FSPCM wood with merbau and meranti for the delignification process was successful in the presence of pores. The leakage test on merbau/soy wax and meranti/soy wax can maintain form material until 40°C and the highest levels of impregnation is merbau/paraffin 56.17%. From the result delignification process on wood can increase PCM absorption, and can improve performance of wood as building insulation. [ABSTRACT FROM AUTHOR]

One of the most important economic challenges, affecting nations, officials, economies, and individuals, is energy. Fossil fuels, such as coal, oil, and natural gas, have long been the primary energy sources used in energy production. emissions from fossil fuels in the long term can accelerate global environmental deterioration and climate change. The development of renewable energy and energy storage technology as an alternative to fossil fuel needs to be done immediately. This article discusses the use of molten salt-based thermal energy storage for storing thermal-based renewable energy such as solar energy. Examples of molten salts based on nitrate, chloride, fluoride and carbonate for thermal storage media at various working temperatures, applications and thermophysical properties are discussed in this article. The conversion of thermal energy to electrical energy using a Stirling engine is also discussed in this article. Several proposed systems, designs, and performance for converting heat energy to electricity using the Stirling engine are introduced and discussed in this article. The prototype Stirling-molten salt system has been analyzed and is available in several studies. As a result, molten salt capability to supply heat over a long period of time and affects the performance of the heat-to-electricity conversion by the Stirling engine. [ABSTRACT FROM AUTHOR]

Electronic devices have been an integral part of human life. Most devices are susceptible to heat, and overheating has become one of the main problems in maintaining the device's durability. Heatsink as a thermal management system takes advantage of the extended surface to transfer heat from the device to be carried away through conduction and convection. This study combines heatsink and Phase Change Material (PCM) to increase the performance of the thermal management system. The heatsink is manufactured using the 3D printing method with a cavity inside the heatsink to insert the PCM. PCM uses the latent state of a material to absorb heat at a constant temperature and is already many used in the thermal storage system. Later in the experiment, the performance of a conventional heatsink is compared with a heatsink that is injected with PCM. The experiment is done with different variations of airspeed: 1m/s, 1.5m/s, and 2m/s, heater power: 30W, 40W, and 50W, and PCM: soy wax and palm wax. The experiment result shows that PCM is effective in lowering the heatsink steady-state temperature, especially under high heat flux when the melting point has been reached with temperature degradation 7.7% for soy wax and 13.3% for palm wax. The performance of palm wax is better than soy wax which has the highest thermal conductance of 2.34W/K and a higher enhancement ratio than soy wax which is 1.62. [ABSTRACT FROM AUTHOR]

Adsorption thermal energy storage (aTES) is one of the possible technologies that could help to eliminate our dependence on fossil fuels. The advantages of the adsorption systems lie in the possibility to supply hot as well as cold, and the fact that the aTES systems have negligible energy losses over time and therefore are also suitable for seasonal storage. Selection of the right adsorption pair to store the maximum amount of energy is then the key factor for high-efficiency system. In this work, we introduce the basic principles of the adsorption thermal energy storage and analyze the pivotal aspects for the high-performance adsorption thermal energy storage, not too dissimilar from the adsorption heat pumps. The adsorbate of choice for the storage applications remains water with the highest energy density coming from high enthalpy of vaporization and high polarity of the water molecules. Modern high-yield adsorbents for adsorption thermal energy storage are nearly without any exception tailored microporous materials with high water affinity such as microporous silica, zeolites and zeolite like materials and metal organic frameworks (MOFs). [ABSTRACT FROM AUTHOR]

In this experimental study, the thermal performance of a lauric acid phase change material (PCM) based rectangular thermal energy storage (TES) system has been observed. The TES system is applicable for waste heat recovery. Further, this waste heat is used for space heating/cooling. TES system is free from climate conditions means itis applicable in every season. The main soul of the TES system is energy-storing materials. Generally, PCMs are used in the TES system as energy-storing materials. In the present work, the charging and discharging temperature profiles in longitudinal and lateral directions of the TES system have been found with the variation in heat transfer fluid flow from 1LPM to 2 LPM. The charging time of the lauric acid-based TES system at 2 LPM decreased by 7.6 % than 1LPM. The heat transfer rate at 5 minutes at the 2 LPM HTF flow rate is 21.87% and 10.98 % higher than the 1 LPM and 1.5 LPM, respectively, from the HTF to the TES system. Furthermore, the TES system raises the interior temperature of the prototype automobile cabin by 9.3°C over the surrounding air temperature. This research is beneficial to the recovery of waste heat from vehicles, furnaces, and boiler exhaust gases. [ABSTRACT FROM AUTHOR]

Solar air heater represents one of the substantial thermal systems that is utilized for collecting the heat of the solar radiation to be used for space air heating and farming products drying. This study aims to investigate the thermal performance of the solar air heater (SAH) with a multiple air pass using different arrangements of the corrugated absorber plate with a metal mesh and phase change material (PCM) as a thermal storage system experimentally. The test rig of SAH was consisted of an external insulated container, absorber corrugated plate, double glass sheets, air fan, and measuring devices. A black-coated corrugated Aluminum sheet of 900 mm in length, 500 mm in width, and thickness of 1 mm was installed inside the SAH container as absorber plate and supplied with 20 kg of Paraffin wax as PCM for thermal storage. Four cases of the SAH with a corrugated absorber plate at different arrangements are evaluated experimentally in April 2022 under Baghdad city climatic conditions to investigate optimal thermal performance of the SAH. Double pass and triple pass air flow SAH are examined in the first and second cases respectively. While a triple pass with a metal mesh and PCM assisted absorber plate are tested in the third and fourth cases respectively. The results revealed that the enhancement in the SAH outlet air temperature for case 4 was 21% compared with other test cases during low solar radiation hours. A relatively low air flowrate of 0.0095 kg/s has reflected a higher outlet air temperature by about 12 % compared with the other air flowrates 0.012 and 0.0134 kg/s considered in this work. Higher thermal efficiency for the solar air heater was 74, 73, 71.6, and 70% for cases 3, 2, 1, and 4 respectively at peak solar radiation hours, while at low solar radiation period, case 4 reflected a higher efficiency by about 15% compared with other test cases. [ABSTRACT FROM AUTHOR]

ANSYS fluent is used to analyze the thermal storage system of a porous medium channel. The dimensions of the porous media tank are 15x15x80 cm. Transient analysis is used to introduce hot fluid into channels with varying porosities (0.3-0.5) and Reynolds numbers (Re = 5040–8400). The results illustrated the influence of axial position, operation period time, Re, and porosity on temperature distribution and the average Nusselt number. Temperature distribution is also shown using Finite Element Method outlines. Temperature measurements will be at their maximum after a longer period of operation (15 min). After 15 minutes of operation, the channel with the greatest porosity (porosity = 0.5) had the highest temperature values. Both tubes were permeable. Nu increases when Re, time, or are lifted along the rectangular duct. The current investigation confirmed both the experimental work and the prior study with error rates of 0.6 and 0.8, respectively. The settings Re = 5040 and = 0.3 show the best heat storage performance. [ABSTRACT FROM AUTHOR]

The numerical modeling of phase change material behavior in a triple heat exchanger is properly studied using COMSOL Multiphysics. The triple heat exchanger has three sides: an interior pipe for cooling and heating with water, an annular space between the second and first interior pipes carrying PCMs (paraffin or lauric acid), and a third side annular space between the outer pipe and the second pipe containing stagnant water. The triple heat exchanger has the following dimensions: 30 cm length and (0.5 in: 2.5 in: 3.5 in) side diameters. To conduct the PCM thermal dynamic, numerous factors such as water flow rates, cooling, heating operation, and PCM types are taken into account. The findings demonstrate that increasing the flow rate will accelerate the present system's heating and cooling processes while maintaining the poor thermal dynamic intensity (11 LPM has the maximum thermal storage performance while 52 LPM has the minimum). The temperature distribution on the intermediate side of PCM is the most significant, with stagnant water having the lowest temperature values. Lauric acid is more sensitive to temperature variations than paraffin; given the same flow rates, lauric acid acquires and loses heat faster than paraffin. The findings correlate well with the experimental data; the highest error rate is roughly 11% in the paraffin situation and 5% in the lauric acid case. [ABSTRACT FROM AUTHOR]

In many thermal systems, including buildings, phase change materials (PCM) are effective thermal energy storage (TES) media. As a result, earlier research must be reviewed in order to gain the best understanding of PCM applications in construction, as well as approaches to increase the efficiency of building cooling and heating applications. The research work for various applications, which include PCM floors only, is reviewed in depth in this article. To identify research requirements for each application, summaries and discussions are undertaken. PCM, PCM kinds. The review's paper techniques are also summarized and evaluated in order to identify research opportunities and constraints. To assist scientists in their work, important results for the future of research of various applications are provided. This paper concentrates on appropriate approaches to reduce energy demand Using PCM as a layer with construction materials like bricks, walls, and wallboard will lessen the negative ambient effect or as (TES) to achieve thermal comfort and enhance building thermal performance while using the least amount of energy possible. In addition, the study highlights the aeration, passive heating, active heating, and cooling systems, allowing them to be used with only minor construction modifications to the original design. [ABSTRACT FROM AUTHOR]

The thermal storage system is an energy-saving technology specially developed to store heat energy temporarily. This model is based on a set of nonlinear equations that include nonlinear terms relating to thermal conductivity, heat source terms, and power law temperature-dependent heat capacity. The nonlinear ordinary differential equation (ODE) is solved with proper boundary conditions using the Taylor series and Hyperbolic function methods. Simple analytical expressions of the temperature distribution through a region have been derived. When our analytical results are compared to earlier analytical data, there is a satisfying level of agreement. The effects of material characteristics on the system's thermal degradation are also studied. [ABSTRACT FROM AUTHOR]

Solar desalination is the process of reducing salt content of brine by utilizing solar heat to produce freshwater. Distillation is widely used as a traditional solar desalination method but it has low evaporation rate. In recent years, solar interfacial evaporation through thermal localization in the vapor-liquid interface has been studied as a promising alternative to evaporation. In this study, charcoal briquette were investigated as an interfacial solar absorber to increase the steam generation. Experiments were performed in 4 single-slope solar stills basin type by using briquette thickness of 10, 15, and 20 mm for 8 hours under sunny daylight. Basin with no charcoal were also examined for comparison. The temperatures were measured at several points within the basin to identify the factors contributing to the seawater evaporation. It has been found that the briquette structure capable of concentrating thermal energy where it is needed for phase change and minimizes heat loss. Addition of charcoal achieve 20 - 30 % improvement of efficiency compared to basin with no charcoal. This performance obtained from several factors such as thermal storage material, latent heat, capillarity, and interconnected pores. [ABSTRACT FROM AUTHOR]

In Indonesia, there are still many metal smelting processes using cupola stoves and induction stoves as well as metal casting using sand casting such as in Ceper, Klaten, Central Java. An analysis of the metal casting plant waste steel slag will be analyzed from a factory that uses induction furnaces and cupola. The major compound in steel slag from induction furnace contains cristobalite and silicon oxide (SiO2) as a major component. EDS spectra of steel slag from induction furnace showed that the major atoms in the slag are carbon and silica with equal ratio. The major compound in steel slag from induction furnace contains silicon oxide (SiO2), quartz (SiO2) and calcium silicate (CaSiO3) as a major component. EDS spectra of steel slag from cupola furnace showed that the major atoms in the slag are silica and carbon with ratio of 2:1. Due to its major compound and surface images, the steel slag from both cupola and induction furnace can be used for some purposes. This material, which is still classified as a solid waste, can be used as aggregate in road superstructures, coarse and fine aggregate in concrete, ballast in railways, agricultural soil fertilizer and high temperature thermal energy storage in solar tower plants. [ABSTRACT FROM AUTHOR]

Post-harvest loss of agricultural products is a significant problem in many developing and expanding countries that are experiencing economic expansion. On the one hand, there is a lack of understanding regarding the sizeable amount of losses, and on the other, there is a lack of knowledge regarding the advantages of applying uncomplicated postharvest and conservation methods. A significant amount of agricultural productivity is lost in many nations. Using the right post harvest technology could help to cut down on food waste. Additionally, it helps to raise product quality, which raises market prices. The most typical way to preserve freshly obtained fruits(grapes) is by drying and storing them. The practice of drying goods outdoors in the sun dates back to ancient times, however there are drawbacks, including a heavy reliance on the weather, slow drying durations, the potential for contamination, etc. These problems may be overcome by using mechanical dryers, although they are energy intensive. Simple mechanical processes and solar-powered drying can lower the moisture content of grapes, enabling longer-term storage. Common methods of raisins processing are the open sun drying and natural air-drying shelter. Both of methods have been long production period, large area, the quality of grapes is low. Mainly traditional solar dryer for grape do not have heat system with lower efficiency. As a result, the drying air condition varies greatly and closely tracks changes in the ambient air condition. The drying process is discontinuous. According to incomplete statistics, the consuming time of grape drying is 15 days with traditional solar dryers. Therefore, the traditional solar dryer is not suitablefor industrial production. the paper mainly dealt with the sustainable self-made solar dryer and heat storage system with nichrome coil. [ABSTRACT FROM AUTHOR]

Evaporation is one of the fundamental components of the water cycle in nature and affects almost all aspects of human society. Especially in the context of global climate change, understanding this process is increasingly important. However, the process itself is also very complex and is influenced by many factors, making it very difficult to estimate its magnitude. As a benchmark, the Penman-Monteith equation is generally accepted, which estimates evaporation using air temperature, atmospheric pressure, wind speed, net radiation, changes in heat storage in water and others. Since measurements of these values may not always be available, many simplified methods have been proposed. In this paper, we consider the Hargreaves-Samani method and the calibration of its parameters by optimizing statistical measures against the Penman-Monteith equation. [ABSTRACT FROM AUTHOR]

Measurement and assessment of thermo-physical properties of magnesium oxychloride cement (MOC) with implemented phase change material based on paraffin wax encapsulated in polymer shell, is presented in the paper. The measurement method and mathematical interpretation of thermal conductivity and specific heat capacity assessment was derived from the Thermophysical Transient Tester 1.02 that was developed at the Institute of Physics, Slovak Academy of Sciences. Within the test, thermal responses between two thermal sources were measured during the step wise heat reference source and source generating step wise heat. It was revealed that both investigated thermal parameters depend on the dosage of PCM in composite mixture, thus porosity of prepared materials and thermal characteristics of PCM itself. The obtained data point to the substantial improvement of heat storage capacity of MOC by the use of powdered PCM. [ABSTRACT FROM AUTHOR]

Molten salt has been widely known to have much utilization, both as thermal storage and as a coolant in several energy generation systems. This study aimed to determine the thermophysical characteristics of molten salt in phase transition using computational fluid dynamics. ANSYS Fluent 2020 was used to solve the governing equations in the phase transition phenomena of molten salt. Experimental parameters from several references were used as input in computational modeling. The object in this study was molten alkali salt, both in pure NaNO3 and KNO3 or a eutectic mixture of both. The salt was put into a heater made of stainless-steel pipe with an outer diameter of 26.67 mm. Heat in the heater was modeled as a boundary condition on the walls of the pipe 10 cm long. The results showed that the molten salt phase transition occurred relatively fast around the melting temperature. [ABSTRACT FROM AUTHOR]

Iraq, daytime load consumption exceeded midnight due to the country's all-year increase in summer power demand. Building air conditioning is the main cause of this. Thus, one way to lower the peak demand would be to generate and consume power at night while storing cold thermal energy to lower the demand for air conditioning during the day. We Suggest a new radiant floor cooling system using two types (spiral and counter geometry) of thermal energy storage (TES) filled with phase-changed materials (PCMs) with night re-cooling using air conditioning (A/C) in the summer of Iraq. This study aims to save and shift energy from nighttime to daytime for two test rooms full-size prototypes made from sandwich panels of dimension (length 2.25 x width 2.95 x height 2.95) m situated in Kirkuk-Iraq, also to clarify the steps to guarantee the thermal storage effect of the suggested cooling system during the day for two test rooms within a very small diurnal temperature range, focusing primarily on the thermal characteristics of PCMs. We investigated the connection between the suggested system's heat flows and indoor air temperature distributions. The results showed a decrease in the room temperature was about 1 when using forced water cooling for the floor room, while it was 2.8 °C using the PCM. The evaporative cooling used in Test 1 to cool the floor and increase the COP of the air conditioner resulted in a 40.2% and 34.79 % for spiral and counter design respectively, reduction in energy use for the entire summer compared to Test 3 and a 28.2 % and 23.55 % for spiral and counter design respectively, reduction in energy compared to Test 2. It is clear from the results that the energy saving of the counter design is (6%) more than that of the spiral design. [ABSTRACT FROM AUTHOR]

Due to the unpredictability of renewable energy, stable storage systems are an essential part of combating global warming. The foundation for the development of more compact and simple-to-fabricate storage components has been laid by investigations into the latent heat transfer that occurs in almost all isothermal situations within phase change material (PCM) storage units. In this study, a horizontal triplex square channel thermal storage unit (TSCTSU) with internal and external longitudinal fins utilizing a PCM with a melting temperature within a range of 38.15 to 42.15 °C was constructed for evaluation as a device for storing power. The effect of mass flow rates and heat transfer fluid (HTF) inlet temperatures on PCM melting and charging under steady and non-steady were thus numerically investigated and, according to the results, the PCM melting process is influenced more significantly by the HTF inlet temperature than by the HTF mass flow rate. Fin length also significantly affected melting time, however, with this time decreasing as fin length increased: as an example, for fin lengths of 42 mm and 47.6 mm, the liquid fraction melting durations were 38 and 34 min, respectively. [ABSTRACT FROM AUTHOR]

Paraffin is considered the ideal candidate for latent heat storage material. However, there is a significant problem related to the mushy region that disrupts the heat transfer process and tends to have a high supercooling degree. High-density polyethylene (HDPE) promotes a stable phase transition for the paraffin during the melting/freezing process. Therefore, the present study evaluates the effect of adding HDPE at a different ratio to form composite paraffin to evaluate the supercooling degree of the composite. Four samples are prepared for the evaluation: pure paraffin and composite paraffin/HDPE at HDPE ratios of 5 wt%, 10 wt% and 15 wt%. The static charging/discharging test is performed to estimate the melting/freezing temperature of the sample. Compared to pure paraffin, there is a significant change in the composite's melting/freezing temperature, which implies the effect of HDPE on the sample. The lowest melting temperature occurs at composite with 5 wt% HDPE with a temperature of 58.4 °C. The lowest freezing temperature and supercooling degree are obtained by the sample with 15 wt% HDPE at 68.6 °C and 9.5 °C, respectively. Further observation by using a scanning electron microscope and Fourier transform infrared is discussed in detail within the article. [ABSTRACT FROM AUTHOR]

In the oil and gas industry, managing large quantities of produced water on a daily basis as the production blocks mature over time can be challenging, alarming for an effective and equally efficient treatment system to be embarked. A great solution would be to transform the produced water into a solar pond. Salt-gradient solar ponds (SGSP) are capable of storing large amounts of heat that could be used for producing electricity. Studies relevant to sodium bicarbonate solar ponds and its corresponding low-grade energy harvest are still at a pioneering stage, particularly in Malaysia. Thus, this paper investigates possible techniques and approaches to optimize thermal efficiency of solar ponds, using simulated produced water with high sodium bicarbonate content for power generation. It was determined that the best time to acquire the highest lower convective zone (LCZ) temperature is between 12 to 3 pm, when sun peaks right above the head. Also, addition of 18.8 litres of hydrochloric acid (HCl) had significantly reduced the pH and turbidity level of the pond, removing algae while improving solution clarity and heat storage at LCZ. Utilization of neoprene rubber sheet and black soil as insulators had proven to optimize the solar pond thermal efficiency, yielding highest LCZ temperature of 52.3°C with a maximum temperature difference of 18°C. Besides, the application of thermoelectric generator (TEG) to convert heat energy into sensible power output was explored through simple laboratory-scaled design and set-up, where a total of eight TEG modules were required to produce 0.28W of electricity. [ABSTRACT FROM AUTHOR]

Many applications require thermal energy for some or the other processes to be carried out. The process needs to be carried out efficiently and without any variations for which mostly the conventional energy sources are utilized. Further the use of non-conventional energy sources is at its boom in the current era. Considering the need of thermal energy and the ever increasing need to utilize the non-conventional resources the paper tries to review work related to thermal energy storage (TES) system. It also helps in adjusting the fluctuations in load. Phase Change Material (PCM) plays a vital role in the TES system. Solar energy was stored in the PCM during the day time and can be utilized as and when required. The PCM can be used in various ways like fins, encapsulated systems, honeycomb structure etc. The TES can be used associated with chemical heat systems, latent heat, sensible heat. The more useful energy is latent heat. From the review it was summarized that TES (PCM) could be an effective way to store thermal energy for the various fields like, textiles, sugar industries, diary plant, hospitals etc. Thus helping us to move a step towards sustainable manufacturing systems. [ABSTRACT FROM AUTHOR]

The aim of this work is to explore the possibilities of phase change materials (PCMs) based thermal energy storage (TES) system for solar water heaters (SWH) to ensure the availability of hot water for domestic purposes during nighttime. The system contains basically two heat absorbing units, namely water storage tank and PCM-based heat storage unit. The storage unit consists of a galvanized iron box with a PCM box filled with Salt Hydrates, which is used as PCM. At the daytime, storage tank is filled with water completely and allowed to circulate between SWH and PCMs. The water receives heat from the SWH and transfers it to the PCMs the PCM change the phase by absorbing latent heat and excess heat being stored as sensible heat. Results showed that about 10 liters more hot water can be utilized from the same storage tank volume. [ABSTRACT FROM AUTHOR]

The requirement for energy is increasing on a large scale in the industrial and domestic sectors due to the rapid industrial growth and human living standards. International organisations are creating strict laws and guidelines at the same time to limit the usage of traditional fossil fuel-based electricity generating. Additionally, fast-developing countries like Oman are putting numerous plans to integrate renewable energy in the residential and industrial sectors as part of their commitment to lessen the potential for global warming. The government is taking proactive steps to use solar-based systems in household applications because Oman has a strong potential for using solar power and has a high demand for electricity from the residential sector. Since Oman has a promising potential to use solar power and a large demand for power from the residential sector, many steps are being taken to use solar-based systems in domestic applications. Presently, the hot water needs of domestic as well as many industrial consumers are met by grid electricity. The solar PV technology is a desirable alternative for using renewable energy. However, installing a solar thermal energy conversion system is a potential way to use solar power for producing hot water because solar thermal collectors have a greater conversion efficiency (55–75%) than PV collectors (10–20%). Thermal energy storage systems are also essential for the efficient use of solar thermal energy. Phase change material (PCM)-based thermal storage, one of the more modern technologies, has been recognised as a dependable solution in earlier investigations. However, for this strategy to be successfully applied in a particular location, it is necessary to analyse the quantity and quality of solar energy available. In this study, the technical feasibility of using PCM thermal storage to supply 200 litres of hot water per day to a residential building is examined. The size and specification of the thermal collector have been selected based on the simulation studies. For this purpose, the system advisor model (SAM) of the National Renewable Energy Lab (NREL), USA, and the weather data of Shinas, Oman, from the NASA database were used. To store 6 MJ of heat collected per day from two solar thermal collectors, 50 kg of paraffin wax having a melting point of 60oC was used. An experimental setup has been fabricated as per the optimum design parameters identified from the simulation studies in SAM, and tests have been conducted to find out the performance of the system. According to the findings, the system could save 1168 kWh of AC electricity annually. [ABSTRACT FROM AUTHOR]

Within the processes of designing and sewing clothes, the stage of design and preparation of technological documents is the initial stage of the sewing industry, in which project solutions of new models of clothing are formed. In developed countries, including a number of countries such as the United States, Japan, Germany, Italy, sufficient success has been achieved in the development of automated methods of designing and manufacturing sewing products, improving the methods of managing technological processes. Currently, it is very important in the design process that the methodology for constructing clothes corresponds to automated design systems, and when drawing simple, constructive cross section, there is little sequence geometric operation. The purpose of the scientific research work is to verify that the sequence of geometric operations is small compared than other methodologies in the process of constructing a teenage clothing set clothing structure from knitted fabrics with a high heat storage property, achieve high efficiency in the development of pattern details and nesting. [ABSTRACT FROM AUTHOR]

Phase change heat storage materials (PCM) are a class of materials with the ability to store or release a large amount of thermal energy at constant temperatures in the form of so-called latent heat, which is the heat that is necessary to supply or remove from the system to make it change the phase. Due to their energy efficiency, these materials are becoming more and more popular and offer a whole range of practical applications. It is worth mentioning, for example, their use for solar energy storage, waste heat recovery or thermal energy management in buildings [1 – 5]. In the experimental part of this work, we focus on the study of phase transformations and energy accumulation and on the characterization of the thermal properties of new industrial PCMs from the Rubitherm® RT series [10 – 12]. These paraffine wax based materials were developed by the German company Rubitherm Technologies GmbH. Relative thermal conductivity of these materials enables their application even in cases requiring rapid temperature changes and efficient heat transfer, such as systems for cooling electronics or thermal management of batteries. Experiments were performed with three commercially available materials Rubitherm® RT18HC, Rubitherm® RT28HC and Rubitherm® RT35HC. These materials are chemically inert, do not subcool during phase transformations and have a long service life. Materials from the Rubitherm® RT series are available in a full range of different melting temperatures, from −9 °C to 100 °C. For this experiment, materials with melting temperatures of 18 °C, 28 °C and 35 °C were chosen, as their names suggest [10 – 12]. [ABSTRACT FROM AUTHOR]

Short-term (daily) and long-term (seasonal) thermal energy storage allows efficient use of renewable thermal energy by replacing fossil fuel systems. In the present research, a three-dimensional numerical simulation of the thermal efficiency of a single-stage and three-stage cascaded shell-and-tube type latent heat thermal energy storage device is carried out using various phase change materials. The mathematical model is based on the fundamental conservation laws of mass, momentum, and energy. Numerical implementation was carried out using built-in solvers of COMSOL Multiphysics v.5.6 software. The numerical solver was verified by comparison with experimental data with acceptable agreement. A comparison of calculations between single and cascade configurations showed that the use of a multi-stage configuration allows for an increase in the temperature range of considered thermal energy storage devices. The use of the internal finned structure of containers almost halves the charging and discharging time. The developed numerical calculation tool can be used in the future to study the thermal efficiency of more complex thermal energy storage device configurations, considering three dimensions and phase transitions. [ABSTRACT FROM AUTHOR]

Due to the increasing population growth and widespread pollution of water sources, the demand for drinking water is constantly increasing. Solar desalination is a promising solution to the problem of water scarcity. Solar distillation technology is an affordable and viable way to turn brackish seawater into drinkable water. Conventional solar energy efficiency and distillation yield are still below par. Many researchers have improved the acting of solar energy by modifying solar energy designs. The principal evenhanded this research is to review the improvement of the production of solar stills through modifications in the designs of their integration with additional heat sources, such as condensers, reflective mirrors, latent heat storage, sensible heat storage, wicking cloth, and use of nanomaterials. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the thermal properties of energy storage units that use phase change material (PCM) by using the ANSYS FLUENT software program. The study focused on four different cases based on the shape of the fins. Numerical and predicted values of temperature distribution inside PCM were compared using the Surface Response Methodology (SRM). The fins were tested with three different sizes of radii 1, 1.5, and 2 mm. The results indicated that using this type of fin resulted in a significant improvement in the efficiency of the thermal energy storage system. Smooth fins had higher thermal performance compared to perforated fins in improving heat transfer, primarily by enhancing conduction inside the PCM, and reducing melting time by 16%, while solidification time was reduced by 5%. It was observed that an increase in the diameter of the perforations led to a reduction in thermal conductivity in PCM. This study contributes to the development of efficient thermal energy storage systems for different applications. [ABSTRACT FROM AUTHOR]

Indonesia is one of tropical country with a relatively warm temperature. Therefore Thermal Energy Storage(TES) need to be installed at building to maintain its comfort room temperature. This research studies the properties of phase change material with coconut oil and expanded graphite mixture for building energy storage applications. As an organic PCM, coconut oil has a low thermal conductivity, therefore expanded graphite are used as the supporting material to enhance thermal performance of the PCM. PCMs was prepared by sonicating expanded graphite into coconut oil with the mass fraction of 0.1 until 0.5 wt%. Thermal conductivity experiment was conducted with Huber thermostatic bath and KD 2 Pro analyzer. The morphology was generated with SEM experiment. The chemical structure of the mixture was generated by FTIR experiment. Particle size of the expanded graphite was generated with PSA experiment. The result in this study showed that expanded graphite and coconut oil mixture PCM show an continues improvement in thermal conductivity. with the highest increase of 19% at mass fraction of 0.5 wt%. also with sociation mixing methods and FTIR result shows that expanded graphite and coconut oil has no change in chemical structure. [ABSTRACT FROM AUTHOR]

Today's world relies on solar energy, a renewable energy source that can be used for a variety of purposes. Cooking, water heating, space heating, power generation, and agricultural drying are some of the most common uses of solar thermal energy. This paper presents experiments on the cooking times of rice and lentils in a solar concentrator combined with and without thermal energy storage systems. The Phase Change Materials (PCM) containers were filled with water, paraffin wax and stearic acid in solid aluminum storage. Experimentally, the heat storage was tested for use in process heating with a concentrated solar collector. This investigation and analysis have been carried out to estimate the effect of temperature on the thermal solar collector. Also study and measure the temperature for different cooking ingredients during the summer period. The experiment was carried out with and without consideration of PCMs, and it achieved a maximum and minimum temperature of 107℃ and 30℃ respectively. [ABSTRACT FROM AUTHOR]

In the article the existing schemes of heat and cold supply of buildings based on absorption heat pumps are analyzed. The optimal thermodynamic characteristics of refrigerants and absorbents are shown, as well as the generation temperatures in an absorption heat pump due to solar energy. The main types of absorbents used in absorption heat pumps are compared. An economic assessment of the use of an absorption heat pump in the heat and cooling supply of a building is presented. To develop absorption heat pumps of a new generation for the conditions of Uzbekistan, carrying out the research works are proposed [ABSTRACT FROM AUTHOR]

Copyright of Proceedings of the International Conference on Renewable Electrical Power Sources - ICREPS is the property of Union of Mechanical & Electrotechnical Engineers & Technicians of Serbia (SMEITS) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heat pumps are important due to their efficiency and a target of climate neutrality. They also reduce the emissions of carbon dioxide. This article deals with the smart mini hybrid heat pump, which is planned to use for heat gain in summer, energy accumulation in the ground storage, and further consumption in winter. This heat pump can get heat from the surroundings or solar collectors. Heat pump water-water has been used in this article. Its input and output parameters were measured, a coefficient of performance (COP) was calculated and also a regression model was created based on the detected operation parameters. The main parameter affecting the operation characteristics of the used heat pump was the temperature of the energy source. The smart mini hybrid heat pump was tested at different temperatures of the heat source. The most suitable source temperature for this heat pump was around 14C with the recorded the highest COP value of 6.71. Based on the results, the smart mini hybrid heat pump can be used to accumulate heat into the accumulation layer and its subsequent removal for heating purposes. When using a combination with thermal solar panels, it is possible to replace the heat pump with a circulation pump in the summer mode. In the winter, it is possible to use photovoltaic panels to produce electricity that would drive the heat pump, which would have a positive effect on the overall energy and emission balance of facilities depending on the location of the building. [ABSTRACT FROM AUTHOR]

This study analyzes the potential integration of a 100 MWel, 36-hour Malta Pumped Heat Energy Storage (PHES) system into the district heating network of the city of Hamburg, Germany, using energy from a nearby offshore wind farm that would otherwise be curtailed to charge the system. Publicly available data showing the times when curtailment instructions were given by the transmission system operator were used to determine the hours during which the storage system should be charged. Malta's proprietary hourly performance model was used to simulate the behavior and performance of different plant configurations. It was shown that this configuration could avoid the curtailment of 227 GWhel of wind energy per year. The study showed that the system could provide 117 GWhel of electricity to the grid, as well as 72 GWhth of thermal energy for Hamburg's district heating network, during periods where less renewable energy was available. This system could reduce the annual CO2 emissions by 101,400 tonnes compared to the coal-fired combined heat and power (CHP) plant that it would replace. [ABSTRACT FROM AUTHOR]

The use of pit thermal energy storages (PTES) enables higher solar fraction in district heating networks by counteracting the mismatch between heat demand and production in solar district heating (SDH) installations. Capital costs linked to land areas with site-specific geological conditions are the deciding factors for PTES constructions. This study investigates non-technical and technical factors for the implementation of PTES in Swedish district heating networks. Having several SDH and PTES installations in operation the country of Denmark is used as a reference. This study, based on literature review, discusses the drivers and challenges for the use of PTES in district heating networks. [ABSTRACT FROM AUTHOR]

Transparent insulation structures play a pivotal role in harnessing solar energy efficiently, akin to the greenhouse effect in the atmosphere. This study undertakes a systematic evaluation of a novel sorbitol- or bio-based polycarbonate (bio-PC) for thermal insulation (TI) structures and hot water collector systems. Employing optical and mechanical methods, the bio-PC was comprehensively characterized on the polymer film level. Subsequently, the technical and ecological performance of these structures in various hot water collectors and systems was rigorously modelled and simulated. Results indicated that the novel bio-PC exhibited superior properties compared to conventional materials like cellulose acetate or fossil-based PC, showcasing promising prospects for widespread adoption. Drawing parallels to the greenhouse effect of CO2, the functional principle of transparent insulation structures is rooted in high solar transmittance and infrared absorbance, primarily governed by carbon-oxygen bonds. While fossil-fuel based transparent insulation materials have been prevalent, they suffer from drawbacks such as average infrared absorbance and susceptibility to yellowing. In contrast, the newly introduced bottom-up biopolymer bio-PC, derived from sorbitol derivatives, offers a compelling alternative. The study sheds light on the potentials and limitations of bio-PC for transparent insulation structures in integrated storage or flat plate collectors, aiming to mitigate environmental impacts associated with traditional materials. Future research directions emphasize refining modelling tools and addressing input data deficiencies, particularly for life cycle analysis. Concurrently, efforts are directed towards enhancing simulation accuracy and reliability through concurrent measurements of collector systems equipped with bio-PC-based transparent insulation. This research underscores the critical role of innovative materials in advancing sustainable energy solutions, with bio-PC emerging as a promising candidate in the realm of transparent insulation technology. [ABSTRACT FROM AUTHOR]

Sweden was among the first countries to install solar thermal plants for district heating (DH) as early as in 1970s. However, in recent years, the focus on solar DH installations has shifted primarily to Denmark and Germany, with only one recent installation reported in Sweden. Nonetheless, due to changes in the overall heating market, the use of large-scale storage (both with and without solar heat) is becoming increasingly important. Despite significant advancements in adopting DH systems, the combination of solar DH with PTES is not well studied from Swedish context. The economic and geological prerequisites for the deployment of PTES remain largely unexplored. This paper explores the integration of large-scale solar thermal systems into DH networks in Sweden, particularly highlighting the feasibility and potential of pit thermal energy storage (PTES) systems. Through findings from a national project, this paper assesses the techno-economic-geological viability of PTES alongside solar thermal collectors, providing insights into the project's methodological approach and initial findings. [ABSTRACT FROM AUTHOR]

Using the thermal building mass as a thermal storage received increasing attention in research during recent years. Due to the large mass of concrete, it offers a large storage capacity and thus a high potential for flexibility. However, passive heat losses during cool down of a thermally activated building influence room temperature and thus limit its flexibility potential. In this contribution a multi-layer activation concept was investigated which thermally decouples the building mass and room air. The study aims to analyse the cool down of a thermally activated building in terms of different charging parameters while considering other heat sources such as solar gains. A dynamic building simulation of a demonstration building was set-up and compared to simulative studies from literature to proof the validity of its dynamic behaviour. In the simulation model the room temperature could be kept above 19 °C between 100 - 190 h. However, when charging the building structure quickly, room temperatures above 24 °C are reached easily. Considering other heat sources such as solar gains, advanced control algorithms are required for efficient operation of the heating system. [ABSTRACT FROM AUTHOR]

The aim of this research is to improve the efficiency of energy systems using the mass of the building as thermal storage. We present a case study of a residential building, in which a detailed monitoring system was installed to measure, among other parameters, the electricity consumption, the indoor air quality, and the operation of the heating system, consisting on a Heat Pump (HP) and a radiant floor. Based on the data collected, both a lumped parameter model (R-C Model) and a Deep Learning (DL) Model have been calibrated to simulate the apartment analyzed. Both models provide a significantly accurate simulation of the apartment under real operating conditions. Then, using the simulation models, different operation scenarios have been analyzed. One of the scenarios considers the thermal inertia of the apartment and the electricity costs forecast to optimize the operation of the HP. Within this scenario, energy savings up to a 35.1%, and electricity costs savings up to a 47.3%, may be achieved during a winter season, when compared to the standardized operation of the HP. [ABSTRACT FROM AUTHOR]

An increasing share of decentralized feed-in is necessary for the transition of district heating networks but it comes with various challenges. Software tools for modelling, simulation and optimization allow a theoretical examination of those challenges and possible solutions. Some of these have been used and further developed in the research project ZellFlex. One selected examination is the flexibility of supply temperatures by varying setpoint temperatures for a decentral solar thermal system (500 m²) integrated into an existing district heating network. The analysis of the supply temperature distribution in the network showed: A decrease of the solar thermal feed-in set point temperature by 5 K compared to the supply temperature of the central heat producer seemed acceptable in terms of security of supply, while a 10 K reduction comes with a high risk of undersupply. Furthermore, it was discovered that the points of time with the lowest supply temperatures at the consumers were just before and after they were provided with solar heat due to specific effects concerning temperature loss of the fluid. [ABSTRACT FROM AUTHOR]

Phase-change material (PCM) is a latent type material that can be integrated with water as thermal energy storage in a solar water heater (SWH). The encapsulation method is usually applied to store PCM in the SWH tank. This method contributes to adding the heat transfer surface area for PCM. Previous research provides information that PCM encapsulation can increase the thermal performance of the SWH system. However, no study has revealed the thermal behavior of horizontal-type SWH tanks related to the number of capsules. The void fraction is a parameter in the tank associated with the number of PCM capsules. This study aims to experimentally investigate the effect of the tank void fraction on the thermal performance of an active-type SWH. The cylindrical capsule of a copper tube was filled with paraffin wax as PCM. Several capsules were put into the tank with various void fractions. Experiments were carried out during the charging process with the solar simulator as a heat source for SWH. Water and PCM temperature were recorded for all variations of void fraction. The temperature data was used to evaluate the thermal performance, then compared each variation. The cumulative heat stored for the void fraction 87.33%, 83.95%, and 79.73% were 13.24 MJ, 16.16 MJ, and16.76 MJ, respectively. The lower the void fraction, the higher the cumulative heat stored in the SWH tank. The mass of PCM determines the thermal energy storage in the SWH system. [ABSTRACT FROM AUTHOR]

Using thermal analysis methods (DTA, VPA, and partly RFA), a melting diagram for a quaternary reciprocal system of potassium and calcium fluorides, chlorides, and tungstates was constructed. The system consists of 11 crystallization volumes, six of which belong to the initial components, four to compounds and a solid solution of tungstates K2WO4·CaWO4. The curves of three-phase monovariant equilibria converge at eight quadruple invariant points: five eutectic and three transitional. Five eutectics of the system are recommended as a heat-storage material (TAM) in heat accumulators (TA) of a phase-transition type, utilizing heat from braking resistors of electrodynamic resistance (EDS) and exhausts of hot gases of internal combustion engines. To establish the operating temperature range in TA, it is advisable to add an additional 5-8 wt. % technical wax with a melting point of 72.6 - 87.2 °C and a specific heat of phase transition of 146-147 kJ/kg. [ABSTRACT FROM AUTHOR]

The climatological mean and daily variation in sea surface temperature (SST) and sea surface winds (SSW) from 2018-2020 in Fiji waters were analyzed. This is the first of such studies investigating the island wake phenomenon in Fiji. The study was conducted on Vitilevu island, the main island of Fiji. This study aimed to investigate the occurrence of the island wake phenomenon on the western leeward side of Vitilevu island. The island wake may potentially occur due to the high topography on the eastern side with mountain peaks of about 1,300m in height blocking trade winds from inducing surface water mixing on the leeward side thus increasing heat storage and initiating the island wake phenomena. The island wake is investigated using GHRSST Lv. 4 daily data. We investigated 1,096 SST images, 217, 2020 and 241 cases of SST wake were found for 2018, 2019 and 2020 respectively. Wind was found to be the main factor inducing the occurrence of the SST wake, with the direction of the wake depending on the speed and direction of the wind. The occurrence of island wake was found to be dominant from November to April annually following the warm wet season in Fiji. The prevalence of the phenomenon on the leeward side of Vitilevu island may influence biological productivity in this area and requires further investigation. [ABSTRACT FROM AUTHOR]

Nowadays, engineers generally prefer phase change materials (PCM) for study and for usage as heat storing materials. This is due to these materials accumulate and deliver a significant quantity of latent heat throughout the melting and freezing processes, which includes transitioning from one phase to another. Engineers may employ this feature of PCM in a variety of ways, including heat energy storage, which allows engineers to store heat or cooling from one operation and use it later or in multiple places. To boost the thermal conductivity of PCM, a heat conductive component viz., nanoparticles is included; these materials are referred to as n-PCM. To investigate the characteristics of produced composites, characterization tests such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermal conductivity tests were performed. The ideal features of n-PCM, its thermophysical properties, as well as the obstacles and future directions of this novel material are discussed in this paper. This study examined and presented various applications and basic properties of n-PCM with alumina/silica. This investigation enhanced the thermal conductivity of n-PCM. This n-PCM demonstrates the enormous potential inherent in thermal energy storage systems. [ABSTRACT FROM AUTHOR]