Other affiliations: Northeast Petroleum University
Bio: Müslüm Arıcı is an academic researcher from Kocaeli University. The author has contributed to research in topics: Materials science & Phase-change material. The author has an hindex of 23, co-authored 111 publications receiving 1599 citations. Previous affiliations of Müslüm Arıcı include Northeast Petroleum University.
TL;DR: In this article, a comparative study is carried out for the wall coupled with PCM and the wall with phase stabilised PCM to reveal the contribution of latent heat to the thermal performance of the wall and to determine the location, thickness and melting temperature of PCM for the maximum exploitation of the latent heat for different climatic conditions.
Abstract: Integration of the phase change materials (PCM) into the external building walls is an efficient method for reduction of energy consumption and regulation of energy demands due to increasing thermal inertia of the walls. This study aims to reveal the contribution of latent heat to the thermal performance of the wall and to determine the location, thickness and melting temperature of PCM for the maximum exploitation of latent heat for different climatic conditions. A comparative study is carried out for the wall coupled with PCM and the wall with Phase Stabilized PCM (PSM) to reveal the improvement provided by the latent heat. The influence of location, fusion temperature and layer thickness of PCM on energy saving, decrement factor and time lag was examined. The annually optimized PCM fusion temperature and layer thickness which utilizes the latent heat at maximum level considering both heating and cooling loads are determined for three cities of Turkey. The computed results show that the monthly optimized PCM melting temperature and PCM layer thickness vary from 6 to 34 °C, from 1 to 20 mm depending on climatic conditions. It was concluded that an optimization study should be conducted in order to prevent PCM behaves like PSM.
TL;DR: In this paper, a review of the optical and thermal performance of window systems containing phase change material (PCM) in buildings is presented, and the challenges and future works of glazing units containing PCM are addressed.
Abstract: Glazing units are important for providing passive solar gain and air ventilation in buildings, but their thermal performance is very poor compared to other building components, which results that energy loss from building envelope becomes much more drastic when the glazing area is large. Incorporating phase change material (PCM) in the glazing unit is an effective approach to increase its thermal performance. The glazing unit containing PCM can absorb part of the solar radiation for thermal energy storage while letting the visible radiation enter the indoor ambient for daylighting, which results in reduction of the temperature fluctuations and improvement of the thermal comfort of indoor occupants. A lot of researchers investigated optical and thermal performance of window systems containing PCM in buildings. However, there is a lack of published research review including numerical methods of optical and thermal performance and physical parameters of PCM used in the glazing units, especially for the optical performance of glazing units containing PCM. The present work reviews the experimental and simulation researches on the optical and thermal performance of glazing units containing PCM and discusses the employed research methods, mathematical models and important conclusions drawn. Finally, the challenges and future works of glazing units containing PCM are addressed.
TL;DR: In this paper, the effect of nanoparticle concentrations and orientation of the activated walls together with the temperature of the hot wall on the melting process and stored energy is investigated numerically, and the results reveal that the highest enhancement is attained for the enclosure filled with ϕ ǫ = 1 Ã Ã % of nanoparticles concentration and heated from bottom.
Abstract: In this study, melting of paraffin wax with Al2O3 nanoparticles in a partially heated and cooled square cavity is investigated numerically. The thermally active parts of the enclosure which are facing each other are kept at different constant temperatures while the other parts of the enclosure are insulated. The effect of nanoparticle concentrations (ϕ = 0 vol%, 1 vol%, 2 vol% and 3 vol%) and orientation of the activated walls together with the temperature of the hot wall on the melting process and stored energy is investigated. Thermophysical properties of NEPCM are considered to be temperature and phase dependent. The computed results showed that considered parameters have a significant effect on the melting rate and stored energy. The results reveal that the highest enhancement is attained for the enclosure filled with ϕ = 1 vol% of nanoparticle concentration and heated from bottom, and nanoparticle concentration beyond ϕ = 1 vol% defeats the purpose thus enhancement decreases.
TL;DR: In this paper, a detailed state-of-the-art review of different battery thermal management system (BTMS) technologies, including natural and forced air-cooling techniques, direct and indirect liquid cooling methods, and cooling by heat pipes, is presented.
Abstract: Electric Vehicles (EVs) have emerged as most promising means of transport owing to the low operational costs, high speed, and energy-efficient battery technologies, where battery thermal management system (BTMS) is possibly the most crucial element of an EV. During the charging/discharging mode of EVs, a major focused area for the researcher is to maintain the optimal working temperature range of the batteries and reduce both the maximum temperature and temperature difference. Suitable and effective cooling methods can significantly reduce the adverse effect of the high surface temperature of battery cells and efficiently augments the battery thermal efficiency, improves the safety of EVs, and increase the service life. In this context, this work presents a detailed state of the art review of different BTMS technologies, including natural and forced air-cooling techniques, direct and indirect liquid cooling methods, and cooling by heat pipes. It is found that the air-cooled BTMS possesses advantageous features such as safe, consistent, and simple design, but the lower heat capacity and thermal efficiency of the air as a cooling medium restricts its application to a low capacity battery. This leads to employment of forced air-cooled BTMS under high charging/discharging rate, in which air flows through the channels inside the battery packs to provide the optimum cooling. Liquid-cooled BTMS is also emerging as one of the most promising cooling technologies, which requires attention to the sealing cover during the design stage to avoid leakages. The integration of metal plates with the mini channel can effectively improve the cooling performance, but the weight of the system is a major concern. Liquid metals, nanofluids, and boiling liquids are considered as the most prominent battery cooling methods owing to their higher thermal conductivity. The advancement in hybrid cooling using fins, nanofluids, PCM along with micro channels-based cooling will significantly improve the battery performance under high charging/discharging rate and attention should be given to compact design with a cheaper cost.
TL;DR: In this article, a numerical study was performed to investigate the melting process in a square enclosure whose two facing walls are maintained at different constant temperatures while the other facing walls were thermally insulated.
Abstract: A comprehensive numerical study is presented to investigate the melting process in a square enclosure whose two facing walls are maintained at different constant temperatures while the other facing walls are thermally insulated. Thermophysical properties of the utilized PCM depend on both temperature and phase. The influence of two different orientations of heated and cooled walls, various lengths and positions of the fin that is attached to the hot wall on phase change process is studied. Besides, analyses are performed considering the contribution of CuO nanoparticles and the contribution of each investigated parameter on the enhancement of the melting process is identified. The obtained results show that all the studied parameters have a remarkable influence on melting rate and energy storage, besides, natural convection has an incontrovertible role in melting process. Assembling the fin in the enclosure shortens the melting time between by 27 to 52% depending on its length and 13 to 68% depending on its position compared to the case without fin. It was also found that assembling fin promotes the melting rate up to 52% depending on the heated wall orientation. A further enhancement is attained with the addition of nanoparticles particularly for shorter fin lengths and bottom-heating case. The computed results also reveal that a combined utilization of a shorter fin together with nanoparticles can provide a thermal performance as high as that of a long fin, thus the utilization of nanoparticles with shorter fins may be an alternative to assembling of long fins without nanoparticles.
TL;DR: In this article, the performance of transparent wood is optimized toward an energy effcient window material that possesses the following attributes: 1) high optical transmittance (≈91%), comparable to that of glass; 2) high clarity with low haze; 3) high toughness (3.03 MJ m−3); 4) low thermal conductivity (0.19 W m−1 K−1) that is more than 5 times lower than glass; and 5) low carbon emissions and scaling capabilities due to its compatibility with industryadopted rotary cutting methods.
Abstract: The energy used for regulating building temperatures accounts for 14% of the primary energy consumed in the U.S. One-quarter of this energy is leaked through ineffcient glass windows in cold weather. The development of transparent composites could potentially provide affordable window materials with enhanced energy effciency. Transparent wood as a promising material has presented desirable performances in thermal and light management. In this work, the performance of transparent wood is optimized toward an energy effcient window material that possesses the following attributes: 1) high optical transmittance (≈91%), comparable to that of glass; 2) high clarity with low haze (≈15%); 3) high toughness (3.03 MJ m−3) that is 3 orders of magnitude higher than standard glass (0.003 MJ m−3); 4) low thermal conductivity (0.19 W m−1 K−1) that is more than 5 times lower than that of glass. Additionally, the transparent wood is a sustainable material, with low carbon emissions and scaling capabilities due to its compatibility with industryadopted rotary cutting methods. The scalable, high clarity, transparent wood demonstrated in current work can potentially be employed as energy effcient and sustainable windows for signifcant environmental and economic benefts.
••01 Jan 2010
TL;DR: Most engineering and scientific phenomena such as the surface of a landscape or the continuously changing temperature at a location are inherently infinite in space or time or both as discussed by the authors, and it is possible to record surface elevation values or the temperature only at some specific locations and times.
Abstract: Most engineering and scientific phenomena, such as the surface of a landscape or the continuously changing temperature at a location are inherently infinite in space or time or both. We cannot measure all the data. Generally it is possible to record surface elevation values or the temperature only at some specific locations and times.
TL;DR: In this article, a literature review on determining the optimum thickness of the thermal insulation material in a building envelope and its effect on energy consumption was carried out, and a practical application on optimizing the insulation thickness was performed, and the effective parameters on the optimum value were investigated.
Abstract: Energy conservation is an increasingly important issue for the residential sector. Therefore, attention towards the thermal performance of building materials, particularly thermal insulation systems for buildings, has grown in recent years. In this study, a literature review on determining the optimum thickness of the thermal insulation material in a building envelope and its effect on energy consumption was carried out. The results, the optimization procedures and the economic analysis methods used in the studies were presented comparatively. Additionally, a practical application on optimizing the insulation thickness was performed, and the effective parameters on the optimum value were investigated.
TL;DR: In this article, a review of previous publications about nanofluid hydrothermal treatment in the presence of magnetic field is presented, where Ferrohydrodynamic and Magnetohydrodynamic (MHD) can take role in simulations.
Abstract: Existence of magnetic field causes heat transfer to reduce in free convection but in several engineering uses for example: electronic application; enhancing heat transfer is a purpose. Thus, nanofluid should be selected as working fluid. Nanofluid is dispersion of very small metal particles in the base fluid. Two phase and single phase are two ways for estimating the behavior of nanofluid. At first model, nanofluid suppose as homogenous fluid without any slip mechanism. But in second method, slip velocities are included. Brownian motion and Thermophoresis impacts are taken into consideration in second approach. In this paper, previous publications about nanofluid hydrothermal treatment in existence of magnetic field are reviewed. Rely of variable and constant magnetic fields, Ferrohydrodynamic (FHD) and Magnetohydrodynamic (MHD) can take role in simulations. Numerical and analytical methods are considered by authors. Results proved that temperature gradient augments with augment of solid particle concentration and buoyancy forces, while it decreases with augment of magnetic field.
Abstract: In recent years, researchers are fascinated to counter problem of PV-efficiency decline arising from high operating temperatures, especially in hot climates. This article conducts a comprehensive review of research activities performed in last 5 years, on cooling techniques with phase-change materials (PCMs), nanofluids and their combined use, leading to efficiency enhancement. By passive cooling approach with PCMs, it is found that maximum enhancement up to 20% in PV-efficiency can be achieved. Effectiveness of PCM for PV is more prominent in summer than in winter. Incorporations of fins inside PCM container at PV rear, results in much improved heat conduction within PCM. Now-a-days, researchers have grown interest in composite PCMs for PV cooling due to their enhanced thermal conductivity. Moreover, better heat regulation as well as PV-surface temperature uniformity can be achieved with two PCMs at a time having different melting points. Studies suggest that combination of passive & active cooling techniques helps in further lowering of PV-cell temperature, leading to enhancement in PV-efficiency with additional thermal power generation. PV-efficiency of water-based hybrid PV/T systems can be improved by 32% by integration with PCM. Although nanofluid-based PV/T systems have been proved to enhance PV-efficiency by more than 60%, but combined use of PCM & nanofluid is more effective approach for PV cooling than individual use of PCM or nanofluid. If combination is made between nanofluid & nano-PCM, electrical power & efficiency can further be enhanced. Nanofluids can also be considered a good spectral filter alternative as they require small thickness and are able to be tuned by varying nanoparticles conc. Finally, environmental impacts & economic viability of mentioned cooling techniques, were discussed. Studies show that PV/PCM systems become expensive & less feasible when operated in single junction due to long payback period up to 20 years. Economic feasibility can be increased by combining passive & active cooling techniques which can increase system compactness and lower its cost.