The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Ahmet Sari - One of the best experts on this subject based on the ideXlab platform.
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fabrication and thermal characterization of kaolin based composite phase change materials for Latent Heat Storage in buildings
Energy and Buildings, 2015Co-Authors: Ahmet SariAbstract:Abstract Three kinds of kaolin-based composite phase change materials (Kb-CPCMs) including capric acid (CA), PEG600, and heptadecane (HD) as organic PCMs were fabricated using vacuum impregnation method for Latent Heat Storage (LHS) application in buildings. The surface morphology, compatibility, maximum ratio for impregnated PCM, LHS properties, thermal endurance, thermal conductivity and its effect on the melting times of prepared Kb-CPCMs were investigated by using microscopy, spectroscopy, calorimetry and thermal methods. The seepage test indicated that CA, PEG600 and HD were impregnated maximally into the kaolin as 17.5, 21 and 16.5 wt%, respectively. The fabricated three composites, K/CA, K/PEG600, and K/HD, have a phase change temperature of 30.71, 5.16 and 22.08 °C and a Latent Heat of 27.23, 32.80 and 34.63 J/g, respectively. The thermal cycling test exposed that the thermal reliability of the Kb-CPCMs slightly changed after repeated 1000 Heating-cooling cycling. The Heat Storage rates of the Kb-CPCMs were increased considerably by adding expanded graphite (EG) in mass faction of 5%. All the prepared Kb-CPCMs have good thermal energy Storage (TES) function for Heating, ventilating and air conditioning (HVAC) in building envelopes because of their suitable LHS properties, high reusability performance and enhanced thermal conductivity.
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thermal properties and thermal reliability of eutectic mixtures of some fatty acids as Latent Heat Storage materials
Energy Conversion and Management, 2004Co-Authors: Ahmet Sari, Hayati Sari, Adem OnalAbstract:Abstract The present study deals with two subjects. The first one is to determine the thermal properties of lauric acid (LA)–stearic acid (SA), myristic acid (MA)–palmitic acid (PA) and palmitic acid (PA)–stearic acid (SA) eutectic mixtures as Latent Heat Storage material. The properties were measured by the differential scanning calorimetry (DSC) analysis technique. The second one is to study the thermal reliability of these materials in view of the change in their melting temperatures and Latent Heats of fusion with respect to repeated thermal cycles. For this aim, the eutectic mixtures were subjected to 360 repeated melt/freeze cycles, and their thermal properties were measured after 0, 90,180 and 360 thermal cycles by the technique of DSC analysis. The DSC thermal analysis results show that the binary systems of LA–SA in the ratio of 75.5:24.5 wt.%, MA–PA in the ratio of 58:42 wt.% and PA–SA in the ratio of 64.2:35.8 wt.% form eutectic mixtures with melting temperatures of 37.0, 42.60 and 52.30 °C and with Latent Heats of fusion of 182.7, 169.7 and 181.7 J g −1 , respectively. These thermal properties make them possible for Heat Storage in passive solar Heating applications with respect to climate conditions. The accelerated thermal cycle tests indicate that the changes in the melting temperatures and Latent Heats of fusion of the studied eutectic mixtures are not regular with increasing number of thermal cycles. However, these materials, Latent Heat energy Storage materials, have good thermal reliability in terms of the change in their thermal properties with respect to thermal cycling for about a one year utility period.
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some fatty acids used for Latent Heat Storage thermal stability and corrosion of metals with respect to thermal cycling
Renewable Energy, 2003Co-Authors: Ahmet Sari, Kamil KaygusuzAbstract:The present study includes thermal stability of some fatty acids as phase change materials (PCMs). The selected fatty acids were stearic, palmitic, myristic and lauric acid with melting temperatures between 40–63°C and industrial-grade with 90–95 % purity. Latent Heat Storage capacity and phase transition temperature of the PCMs were determined by Differential Scanning Calorimetry (DSC) technique as a function of after repeated thermal cycles such as 40, 410, 700 and 910. The present work also comprises the investigation of corrosion resistance of some construction materials to the fatty acids over a long period. The containment materials tested were stainless steel (SS 304 L), carbon steel (steel C20), aluminium (Al) and copper (Cu). Gravimetric analysis as mass loss (mg/cm2), corrosion rate (mg/day) and a microscopic or matellographic investigation were performed for corrosion tests after 910 thermal cycles. DSC measurements showed that all fatty acids investigated as PCMs have a good thermal stability as a function of Latent Heat and phase transition temperature range for an actual middle-term thermal energy Storage utility. However, in long-term solar thermal applications, the palmitic acid and myristic acid may be considered more suitable PCMs than the others. From the gravimetric and metallographic results, it can be concluded that stainless steel (SS 304L) with chromium oxide (Cr2O3) surface layer and Al with aluminium oxide (Al2O3) surface layer are essentially compatible with the investigated fatty acids. Carbon steel (Steel C20) and Cupper (Cu) are only preferantially compatible with PCMs.
D. Buddhi - One of the best experts on this subject based on the ideXlab platform.
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thermal cycle testing of calcium chloride hexahydrate as a possible pcm for Latent Heat Storage
Solar Energy Materials and Solar Cells, 2008Co-Authors: V V Tyagi, D. BuddhiAbstract:In order to study the changes in Latent Heat of fusion and melting temperature of calcium chloride hexahydrate (CaCl2·6H2O) inorganic salt as a Latent Heat Storage material, a thousand accelerated thermal cycle tests have been conducted. The effect of thermal cycling and the reliability in terms of the changing of the melting temperature using a differential scanning calorimeter (DSC) is determined. It has been noticed that the CaCl2·6H2O melts between a stable range of temperature and has shown small variations in the Latent Heat of fusion during the thermal cycling process. Thus, it can be a promising phase change material (PCM) for Heating and cooling applications for various building/Storage systems.
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thermal performance evaluation of a Latent Heat Storage unit for late evening cooking in a solar cooker having three reflectors
Energy Conversion and Management, 2003Co-Authors: D. Buddhi, Smita Sharma, Atul SharmaAbstract:In this paper, a phase change material (PCM) Storage unit for a solar cooker was designed and developed to store energy during sunshine hours. The stored energy was utilised to cook food in the late evening. Commercial grade acetanilide (melting point 118.9 °C, Latent Heat of fusion 222 kJ/kg) was used as a Latent Heat Storage material. Evening cooking experiments were conducted with different loads and loading times during the winter season. The experimental results showed that late evening cooking is possible in a solar cooker having three reflectors to enhance the incident solar radiation with the PCM Storage unit.
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thermal cycle test of urea for Latent Heat Storage applications
International Journal of Energy Research, 2001Co-Authors: Atul Sharma, D. Buddhi, S D Sharma, R. L. SawhneyAbstract:Accelerated thermal cycle tests for melt/freeze cycles of urea were conducted. Urea has shown a very high degradation in its Latent Heat and melting point within the first few cycles and did not melt after a few cycles. It is recommended that urea should not be used as a Latent Heat Storage material. Copyright © 2001 John Wiley & Sons, Ltd.
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Design, development and performance evaluation of a Latent Heat Storage unit for evening cooking in a solar cooker
Energy Conversion and Management, 2000Co-Authors: S D Sharma, D. Buddhi, R. L. Sawhney, Atul SharmaAbstract:In this paper, a PCM Storage unit for a solar cooker was designed and developed to store solar energy during sunshine hours. The stored energy was utilized to cook food in the evening. Commercial grade acetamide was used as a Latent Heat Storage material. Cooking experiments were conducted with different loads and loading times during the summer and winter seasons. The thermal performance of a solar cooker with the PCM Storage unit was compared with a standard solar cooker. The experimental results showed that evening cooking is possible with a solar cooker having the PCM Storage unit and is not possible in a standard solar cooker.
Hamid El Qarnia - One of the best experts on this subject based on the ideXlab platform.
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thermal performance of a solar Latent Heat Storage unit using rectangular slabs of phase change material for domestic water Heating purposes
Energy and Buildings, 2019Co-Authors: Radouane Elbahjaoui, Hamid El QarniaAbstract:Abstract In this paper, the thermal performance of a rectangular Latent Heat Storage unit (LHSU) coupled with a flat-plate solar collector was investigated numerically. The Storage unit consists of a number of vertically oriented slabs of phase change material (PCM) exchanging Heat with water acting as Heat transfer fluid (HTF). During the day (charging mode), the water Heated by the solar collector goes into the LHSU and transfers Heat to the solid PCM which melts and hence stores Latent thermal energy. The stored thermal energy is later transferred to the cold water during the night (discharging process) to produce useful hot water. The Heat transfer process was modeled by developing a numerical model based on the finite volume approach and the conservation equations of mass, momentum, and energy. The developed numerical model was validated by comparing the simulation results, obtained by a self-developed code, with the experimental, numerical and theoretical results published in the literature. The numerical calculations were conducted for three commercial phase change materials having different melting points to find the optimum design of the LHSU for the meteorological conditions of a representative day of the month of July in Marrakesh city, Morocco. The design optimization study aims to determine the number of PCM slabs, water mass flow rate circulating in the solar collector and total mass of PCM that maximize the Latent Storage efficiency. The thermal performance of the LHSU and the flow characteristics were investigated during both charging and discharging processes. The results show that the amount of Latent Heat stored in the optimum design of the Storage unit during the charging process is about 19.3 MJ, 16.54 MJ, and 12.79 MJ for RT42, RT50, and RT60, respectively. The results also indicate that depending on the mass flow rate of HTF, the water outlet temperature during the discharging process varies within the temperature ranges 43.6 °C-24 °C, 51.7 °C-24 °C, and 62.86 °C-24 °C for RT42, RT50, and RT60, respectively.
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numerical analysis of the thermal behaviour of a shell and tube Heat Storage unit using phase change materials
Applied Mathematical Modelling, 2009Co-Authors: Hamid Ait Adine, Hamid El QarniaAbstract:Abstract This work presents a numerical study of a Latent Heat Storage unit (LHSU) consisting of a shell-and-tube. The shell space is filled with two phase change materials (PCMs), P116 and n -octadecane, with different melting temperatures (50 °C and 27.7 °C, respectively). A Heat transfer fluid (HTF: water) flows by forced convection through the inner tube, and transfers the Heat to PCMs. In order to compare the thermal performances of the Latent Heat Storage unit using two phase change materials (LHSU2) and a single PCM (LHSU1), a mathematical model based on the conservation energy equations was developed and validated with experimental data. Several numerical investigations were conducted in order to examine the impact of the key parameters: the HTF inlet temperature (ranges from 50 to 60 °C), the mass flow rate of the HTF and the proportion mass of PCMs, on the thermal performances of the Latent Heat Storage units using two PCMs and a single PCM, during charging process (melting). This parametric study provides guidelines for system thermal performance and design optimization.
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numerical analysis of a coupled solar collector Latent Heat Storage unit using various phase change materials for Heating the water
Energy Conversion and Management, 2009Co-Authors: Hamid El QarniaAbstract:A theoretical model based on the energy equations was developed to predict the thermal behaviour and performance of a solar Latent Heat Storage unit (LHSU) consisting of a series of identical tubes embedded in the phase change material (PCM). During charging mode, a Heat transfer fluid (hot water) from the solar collector passes through the tubes and transfers the collecting Heat of solar radiation to the PCM. The Heat stored in the liquid PCM is next transferred to water during discharging mode to produce Heating water. A simulation program based on the finite volume approach was also developed to numerically evaluate the thermal performance of the LHSU. The model was first validated by comparing the results of numerical simulations to the experimental data. A series of numerical simulations were conducted for three kinds of PCM (n-octadecane, Paraffin wax and Stearic acid) to find the optimum design for a given summer climatic conditions of Marrakech city: solar radiation and ambient temperature. Optimization of the LHSU involves determination of the mass of the PCM, the number of tubes, and the flow rate water in solar collector that maximise the thermal Storage efficiency. Several simulations were also made to study the effect of the flow rate water on its outlet temperature, during the discharging mode.
R. L. Sawhney - One of the best experts on this subject based on the ideXlab platform.
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thermal cycle test of urea for Latent Heat Storage applications
International Journal of Energy Research, 2001Co-Authors: Atul Sharma, D. Buddhi, S D Sharma, R. L. SawhneyAbstract:Accelerated thermal cycle tests for melt/freeze cycles of urea were conducted. Urea has shown a very high degradation in its Latent Heat and melting point within the first few cycles and did not melt after a few cycles. It is recommended that urea should not be used as a Latent Heat Storage material. Copyright © 2001 John Wiley & Sons, Ltd.
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Design, development and performance evaluation of a Latent Heat Storage unit for evening cooking in a solar cooker
Energy Conversion and Management, 2000Co-Authors: S D Sharma, D. Buddhi, R. L. Sawhney, Atul SharmaAbstract:In this paper, a PCM Storage unit for a solar cooker was designed and developed to store solar energy during sunshine hours. The stored energy was utilized to cook food in the evening. Commercial grade acetamide was used as a Latent Heat Storage material. Cooking experiments were conducted with different loads and loading times during the summer and winter seasons. The thermal performance of a solar cooker with the PCM Storage unit was compared with a standard solar cooker. The experimental results showed that evening cooking is possible with a solar cooker having the PCM Storage unit and is not possible in a standard solar cooker.
Atul Sharma - One of the best experts on this subject based on the ideXlab platform.
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thermal performance evaluation of a Latent Heat Storage unit for late evening cooking in a solar cooker having three reflectors
Energy Conversion and Management, 2003Co-Authors: D. Buddhi, Smita Sharma, Atul SharmaAbstract:In this paper, a phase change material (PCM) Storage unit for a solar cooker was designed and developed to store energy during sunshine hours. The stored energy was utilised to cook food in the late evening. Commercial grade acetanilide (melting point 118.9 °C, Latent Heat of fusion 222 kJ/kg) was used as a Latent Heat Storage material. Evening cooking experiments were conducted with different loads and loading times during the winter season. The experimental results showed that late evening cooking is possible in a solar cooker having three reflectors to enhance the incident solar radiation with the PCM Storage unit.
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thermal cycle test of urea for Latent Heat Storage applications
International Journal of Energy Research, 2001Co-Authors: Atul Sharma, D. Buddhi, S D Sharma, R. L. SawhneyAbstract:Accelerated thermal cycle tests for melt/freeze cycles of urea were conducted. Urea has shown a very high degradation in its Latent Heat and melting point within the first few cycles and did not melt after a few cycles. It is recommended that urea should not be used as a Latent Heat Storage material. Copyright © 2001 John Wiley & Sons, Ltd.
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Design, development and performance evaluation of a Latent Heat Storage unit for evening cooking in a solar cooker
Energy Conversion and Management, 2000Co-Authors: S D Sharma, D. Buddhi, R. L. Sawhney, Atul SharmaAbstract:In this paper, a PCM Storage unit for a solar cooker was designed and developed to store solar energy during sunshine hours. The stored energy was utilized to cook food in the evening. Commercial grade acetamide was used as a Latent Heat Storage material. Cooking experiments were conducted with different loads and loading times during the summer and winter seasons. The thermal performance of a solar cooker with the PCM Storage unit was compared with a standard solar cooker. The experimental results showed that evening cooking is possible with a solar cooker having the PCM Storage unit and is not possible in a standard solar cooker.
