The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Katsunori Nagano - One of the best experts on this subject based on the ideXlab platform.
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Thermal and electrical performances of semi-transparent photovoltaic glazing integrated with translucent Vacuum Insulation Panel and Vacuum glazing
Energy Conversion and Management, 2020Co-Authors: Ali Radwan, Takao Katsura, Saim Memon, Ahmed A. Serageldin, Makoto Nakamura, Katsunori NaganoAbstract:Abstract The development of smart windows must provide low solar heat gain with a low overall heat transfer coefficient, avoid humidity and condensation in cold regions, generate clean electricity, and admit comfortable levels of daylight. Therefore, methods for integrating semi-transparent (or 50.8% transparent) CdTe solar cell strings-based glazing with structured-cored mesh translucent Vacuum Insulation Panels and indium sealed Vacuum glazing are described for modernizing smart windows. This study reports experimental and theoretical studies on the thermal and electrical performances of six different glazing systems. These systems include semi-transparent photovoltaic glazing (GPV), Vacuum glazing (VG), translucent Vacuum Insulation Panel (GVIP), semi-transparent PV with VG (VGPV), and semi-transparent PV with translucent Vacuum Insulation Panel (VIPPV), and their performances will be compared with that seen with single glazing (SG). These glazing systems are designed, constructed, and tested using a hot box calorimeter, and with and without the effects of simulated indoor solar radiation. The center-of-pane U-values, the transient temperature variations of the inner and outer surfaces of the glazing systems, the open circuit voltages, the short circuit currents, the fill factors, and the steady-state temperature contours were determined. For the first time, the moisture condensation pattern is also depicted for these systems and will be of value for applications in harsh, cold regions. A 3D finite-volume heat transfer model is developed and validated with the experimental results, allowing comparison of the thermal performances of these glazing systems under ASTM boundary conditions. The results showed that the VGPV system achieved a lower U-value than did the VIPPV system. The steady-state center-of-pane temperature differences seen with a solar irradiation level of 1000 W·m−2 are 55 °C, 32.5 °C and 5 °C for the VGPV, VIPPV, and GPV systems, respectively. The validated center-of-pane U-values for the VG, VGPV, VIPPV, and GPV systems, each with dimensions of 15 cm × 15 cm, are predicted to be 1.3, 1.2, 1.8, and 6.1 W·m-2K−1, respectively. The results also show that the use of either the VGPV or VG systems eliminates moisture condensation. It is concluded that VGPV and VIPPV generate comparatively less power but provide higher thermal Insulation.
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thermal performance analysis of a new structured core translucent Vacuum Insulation Panel in comparison to Vacuum glazing experimental and theoretically validated analyses
Solar Energy, 2020Co-Authors: Takao Katsura, Ali Radwan, Saim Memon, Makoto Nakamura, Katsunori NaganoAbstract:Abstract The notion at which, nowadays, building sector is being recognized to be nearly zero-energy buildings (NZEBs) relies partly on the thermal performance of its fabric Insulation. Vacuum glazing (VG) technology attracted the research interest as an option to reduce heat loss through windows. However, the total glazing thermal transmittance (U-value) for VG increases with the use of smaller glazing area due to the edge-seal effects, due to the thermal short-circuit around the edges and the overall construction cost of VG leading to an unaffordable option to deal with energy conservation of buildings. Therefore, this study aims to propose a new structured core transparent Vacuum Insulation Panel (TVIP) to accomplish Insulation for the windows without edge sealing effect, with lower cost and can be easily retrofitted to the conventional windows of the existing buildings. To do this, VG and TVIP were constructed and their thermal conductivity were measured using heat flow meter apparatus. In addition, a 3D finite volume model considering the effect of surface to surface radiation, gas conduction, and thermal bridges through the spacer material and sealing material is developed. The model is validated with the experiments in this work and with the data for VG in the literature. The effect of Vacuum pressure increase is simulated to mimic the Vacuum deterioration problem and the effect of glazing size on the Insulation performance of both VG and TVIP were investigated. The results indicate that for a smaller glazing area of less than 30 cm × 30 cm, the TVIP accomplished lower U-value compared with the VG at Vacuum pressure of 0.1 Pa and 1 Pa. While, at a Vacuum pressure of 10 Pa, the TVIP attained a lower U-value over the entire range of the investigated glazing sizes. Further, the edge-seal effect in the VG is diminished with the use of TVIP. Furthermore, the material cost per unit area of the TVIP is three times less than the cost of VG at laboratory scale. The results of the current study can guide Vacuum window designers and researchers to further enhance the performance of TVIP based window to compete for the VG in the markets.
Ali Radwan - One of the best experts on this subject based on the ideXlab platform.
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Thermal and electrical performances of semi-transparent photovoltaic glazing integrated with translucent Vacuum Insulation Panel and Vacuum glazing
Energy Conversion and Management, 2020Co-Authors: Ali Radwan, Takao Katsura, Saim Memon, Ahmed A. Serageldin, Makoto Nakamura, Katsunori NaganoAbstract:Abstract The development of smart windows must provide low solar heat gain with a low overall heat transfer coefficient, avoid humidity and condensation in cold regions, generate clean electricity, and admit comfortable levels of daylight. Therefore, methods for integrating semi-transparent (or 50.8% transparent) CdTe solar cell strings-based glazing with structured-cored mesh translucent Vacuum Insulation Panels and indium sealed Vacuum glazing are described for modernizing smart windows. This study reports experimental and theoretical studies on the thermal and electrical performances of six different glazing systems. These systems include semi-transparent photovoltaic glazing (GPV), Vacuum glazing (VG), translucent Vacuum Insulation Panel (GVIP), semi-transparent PV with VG (VGPV), and semi-transparent PV with translucent Vacuum Insulation Panel (VIPPV), and their performances will be compared with that seen with single glazing (SG). These glazing systems are designed, constructed, and tested using a hot box calorimeter, and with and without the effects of simulated indoor solar radiation. The center-of-pane U-values, the transient temperature variations of the inner and outer surfaces of the glazing systems, the open circuit voltages, the short circuit currents, the fill factors, and the steady-state temperature contours were determined. For the first time, the moisture condensation pattern is also depicted for these systems and will be of value for applications in harsh, cold regions. A 3D finite-volume heat transfer model is developed and validated with the experimental results, allowing comparison of the thermal performances of these glazing systems under ASTM boundary conditions. The results showed that the VGPV system achieved a lower U-value than did the VIPPV system. The steady-state center-of-pane temperature differences seen with a solar irradiation level of 1000 W·m−2 are 55 °C, 32.5 °C and 5 °C for the VGPV, VIPPV, and GPV systems, respectively. The validated center-of-pane U-values for the VG, VGPV, VIPPV, and GPV systems, each with dimensions of 15 cm × 15 cm, are predicted to be 1.3, 1.2, 1.8, and 6.1 W·m-2K−1, respectively. The results also show that the use of either the VGPV or VG systems eliminates moisture condensation. It is concluded that VGPV and VIPPV generate comparatively less power but provide higher thermal Insulation.
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thermal performance analysis of a new structured core translucent Vacuum Insulation Panel in comparison to Vacuum glazing experimental and theoretically validated analyses
Solar Energy, 2020Co-Authors: Takao Katsura, Ali Radwan, Saim Memon, Makoto Nakamura, Katsunori NaganoAbstract:Abstract The notion at which, nowadays, building sector is being recognized to be nearly zero-energy buildings (NZEBs) relies partly on the thermal performance of its fabric Insulation. Vacuum glazing (VG) technology attracted the research interest as an option to reduce heat loss through windows. However, the total glazing thermal transmittance (U-value) for VG increases with the use of smaller glazing area due to the edge-seal effects, due to the thermal short-circuit around the edges and the overall construction cost of VG leading to an unaffordable option to deal with energy conservation of buildings. Therefore, this study aims to propose a new structured core transparent Vacuum Insulation Panel (TVIP) to accomplish Insulation for the windows without edge sealing effect, with lower cost and can be easily retrofitted to the conventional windows of the existing buildings. To do this, VG and TVIP were constructed and their thermal conductivity were measured using heat flow meter apparatus. In addition, a 3D finite volume model considering the effect of surface to surface radiation, gas conduction, and thermal bridges through the spacer material and sealing material is developed. The model is validated with the experiments in this work and with the data for VG in the literature. The effect of Vacuum pressure increase is simulated to mimic the Vacuum deterioration problem and the effect of glazing size on the Insulation performance of both VG and TVIP were investigated. The results indicate that for a smaller glazing area of less than 30 cm × 30 cm, the TVIP accomplished lower U-value compared with the VG at Vacuum pressure of 0.1 Pa and 1 Pa. While, at a Vacuum pressure of 10 Pa, the TVIP attained a lower U-value over the entire range of the investigated glazing sizes. Further, the edge-seal effect in the VG is diminished with the use of TVIP. Furthermore, the material cost per unit area of the TVIP is three times less than the cost of VG at laboratory scale. The results of the current study can guide Vacuum window designers and researchers to further enhance the performance of TVIP based window to compete for the VG in the markets.
Tetsuo Uchikoshi - One of the best experts on this subject based on the ideXlab platform.
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Preparation and characterization of hollow silica nanocomposite functionalized with UV absorbable molybdenum cluster
Advanced Powder Technology, 2020Co-Authors: Thi Kim Ngan Nguyen, Fabien Grasset, Stéphane Cordier, Maria Amela-cortes, Yoshio Matsui, Naoki Ohashi, Naoto Shirahata, Tetsuo UchikoshiAbstract:The nanoparticle-based material technology has recently opened a new heat shielding material generation for window applications such as aerogel, Vacuum Insulation Panel or nanospace materials. Aiming to prepare a nanospace-based heat Insulation material functionalized with an ultraviolet (UV) absorbent, the Mo-6 cluster-deposited hollow silica nanoparticles (HSNs) were prepared by the Vacuum impregnation process (VIP). The pore channels of the hollow silica wall filled with the Cs-2[Mo6I8i(OCOC2F5)(6)(a)] octahedral cluster (CMIF) were confirmed by an HR-TEM coupled EDX device, ICP-OES and BET analysis. The retention of the octahedral structure or the typical optical property of the Mo-6 cluster in the pores of the HSNs was demonstrated by ultraviolet (UV) light absorption and photoluminescence spectroscopes even though the powders were heated to 200 degrees C. The multi-functional CMIF@HSNs nanocomposite could adsorb the UV rays under 400 nm and scatter the NIR light through the pores of the silica wall in order to reduce the heat passing a window. For this purpose, the film preparation based on the CMIF@HSNs nanocomposite was performed by dip coating in the commercially available top coat suspension (TCS) on soda lime glass. Excellent mechanical and optical properties of the CMIF@HSNs-based thin film were visibly obtained with a relative transmittance. This study suggests a potential Insulation material prepared by a high efficiency and simple method for reducing the air temperature in buildings.
Takao Katsura - One of the best experts on this subject based on the ideXlab platform.
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Thermal and electrical performances of semi-transparent photovoltaic glazing integrated with translucent Vacuum Insulation Panel and Vacuum glazing
Energy Conversion and Management, 2020Co-Authors: Ali Radwan, Takao Katsura, Saim Memon, Ahmed A. Serageldin, Makoto Nakamura, Katsunori NaganoAbstract:Abstract The development of smart windows must provide low solar heat gain with a low overall heat transfer coefficient, avoid humidity and condensation in cold regions, generate clean electricity, and admit comfortable levels of daylight. Therefore, methods for integrating semi-transparent (or 50.8% transparent) CdTe solar cell strings-based glazing with structured-cored mesh translucent Vacuum Insulation Panels and indium sealed Vacuum glazing are described for modernizing smart windows. This study reports experimental and theoretical studies on the thermal and electrical performances of six different glazing systems. These systems include semi-transparent photovoltaic glazing (GPV), Vacuum glazing (VG), translucent Vacuum Insulation Panel (GVIP), semi-transparent PV with VG (VGPV), and semi-transparent PV with translucent Vacuum Insulation Panel (VIPPV), and their performances will be compared with that seen with single glazing (SG). These glazing systems are designed, constructed, and tested using a hot box calorimeter, and with and without the effects of simulated indoor solar radiation. The center-of-pane U-values, the transient temperature variations of the inner and outer surfaces of the glazing systems, the open circuit voltages, the short circuit currents, the fill factors, and the steady-state temperature contours were determined. For the first time, the moisture condensation pattern is also depicted for these systems and will be of value for applications in harsh, cold regions. A 3D finite-volume heat transfer model is developed and validated with the experimental results, allowing comparison of the thermal performances of these glazing systems under ASTM boundary conditions. The results showed that the VGPV system achieved a lower U-value than did the VIPPV system. The steady-state center-of-pane temperature differences seen with a solar irradiation level of 1000 W·m−2 are 55 °C, 32.5 °C and 5 °C for the VGPV, VIPPV, and GPV systems, respectively. The validated center-of-pane U-values for the VG, VGPV, VIPPV, and GPV systems, each with dimensions of 15 cm × 15 cm, are predicted to be 1.3, 1.2, 1.8, and 6.1 W·m-2K−1, respectively. The results also show that the use of either the VGPV or VG systems eliminates moisture condensation. It is concluded that VGPV and VIPPV generate comparatively less power but provide higher thermal Insulation.
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thermal performance analysis of a new structured core translucent Vacuum Insulation Panel in comparison to Vacuum glazing experimental and theoretically validated analyses
Solar Energy, 2020Co-Authors: Takao Katsura, Ali Radwan, Saim Memon, Makoto Nakamura, Katsunori NaganoAbstract:Abstract The notion at which, nowadays, building sector is being recognized to be nearly zero-energy buildings (NZEBs) relies partly on the thermal performance of its fabric Insulation. Vacuum glazing (VG) technology attracted the research interest as an option to reduce heat loss through windows. However, the total glazing thermal transmittance (U-value) for VG increases with the use of smaller glazing area due to the edge-seal effects, due to the thermal short-circuit around the edges and the overall construction cost of VG leading to an unaffordable option to deal with energy conservation of buildings. Therefore, this study aims to propose a new structured core transparent Vacuum Insulation Panel (TVIP) to accomplish Insulation for the windows without edge sealing effect, with lower cost and can be easily retrofitted to the conventional windows of the existing buildings. To do this, VG and TVIP were constructed and their thermal conductivity were measured using heat flow meter apparatus. In addition, a 3D finite volume model considering the effect of surface to surface radiation, gas conduction, and thermal bridges through the spacer material and sealing material is developed. The model is validated with the experiments in this work and with the data for VG in the literature. The effect of Vacuum pressure increase is simulated to mimic the Vacuum deterioration problem and the effect of glazing size on the Insulation performance of both VG and TVIP were investigated. The results indicate that for a smaller glazing area of less than 30 cm × 30 cm, the TVIP accomplished lower U-value compared with the VG at Vacuum pressure of 0.1 Pa and 1 Pa. While, at a Vacuum pressure of 10 Pa, the TVIP attained a lower U-value over the entire range of the investigated glazing sizes. Further, the edge-seal effect in the VG is diminished with the use of TVIP. Furthermore, the material cost per unit area of the TVIP is three times less than the cost of VG at laboratory scale. The results of the current study can guide Vacuum window designers and researchers to further enhance the performance of TVIP based window to compete for the VG in the markets.
Zhaofeng Chen - One of the best experts on this subject based on the ideXlab platform.
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Preparation and Characterization of a Type of Green Vacuum Insulation Panel Prepared with Straw Core Material.
Materials (Basel Switzerland), 2020Co-Authors: Lu Wang, Zhaofeng Chen, Yong Yang, Yiyou Hong, Zhou ChenAbstract:The Vacuum Insulation Panel (VIP), regarded as the most promising high-performance thermal Insulation material, still has application limitations because of its high cost. In this paper, VIPs using natural straw as the core material are prepared. The fiber saturation point (FSP) is important in order to determine the optimum for the use of renewable straw materials as a potential VIP core. The microstructure of straw core material, together with the relationship between the moisture content, the diametral compression strength, and the thermal conductivity of as-prepared straw VIPs are investigated. Compression characteristics of straw core material and heat Insulation mechanism within the straw VIP envelope enclosure are analyzed. Total thermal conductivity of a straw VIP is sensitive to both the inner pressure and the moisture content of straw core material. The optimum drying process for straw VIPs is heating the straw core material at a temperature of 120 ℃ for 60 min, with its center-of-Panel value being about 3.8 mW/(m·K).
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Correlation between the Thermo-physical Properties and Core Material Structure of Vacuum Insulation Panel: Role of Fiber Types
Fibers and Polymers, 2018Co-Authors: Zhaofeng Chen, Yong Yang, Zhou Chen, Junxiong Zhang, Liu YangAbstract:Vacuum Insulation Panel (VIP), which is composed of an evacuated core material encapsulated in an envelope and supplemented with a desiccant, is a high performance thermal Insulation material. In this paper, thermos-physical properties of chopped fiber, centrifugal-spinneret-blow (CSB) fiber, flame-spinneret-blow (FSB) fiber and hybrid (CSB: FSB=1:1) fiber as fillers of Vacuum Insulation Panel are explored. The results show that the increase of pore size can improve thermal Insulation property; fibers distribute in 2-D structure, which can reduce the heat conduction, leads to reduce the thermal conductivity. VIP with chopped fiber has the best thermal Insulation, and thermal conductivity is 1.4 mW/m.K. Due to difference of core materials, thermal Insulation characteristics of VIP can be divided into three distinct regions based on the internal pressure range, i.e., (I) ≥12000 Pa region, (II) 80-12000 Pa region, (III) ≤ 80 Pa region. It also finds that service life of VIP can be improved by the reducing the pore size of core materials. VIP with different core materials shows different degradation and the degradation rate of VIP with FSB core material is minimum.
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Fabrication and characterization of low-cost and green Vacuum Insulation Panels with fumed silica/rice husk ash hybrid core material
Materials & Design, 2016Co-Authors: Cheng Dong Li, Muhammad Umar Saeed, Zhaofeng Chen, Teng Zhou XuAbstract:Abstract Novel fiber/powder hybrid core materials (HCMs) containing various combination ratios of fumed silica (FS), rice husk ash (RHA), carbon black, titanium dioxide and polyester chopped strand were prepared by dry powder mixing method. The HCMs and their corresponding Vacuum Insulation Panel (VIP) samples were thoroughly characterized to get insight information about their microstructures, structural stability and thermal conductivities. The results revealed that the HCMs possessed a hierarchical meso-/macro-structure with a high porosity of 80.5–87.9% and a fine pore size of 150.9–210.3 nm. Both compression and rebound ratios of the VIPs initially increased (up to ~ 59%) with the increasing RHA content and thereafter decreased till 39% and 31% respectively. The initial total thermal conductivities of the VIPs were ~ 5.5 mW/(m K), which increased with the increasing RHA content as well. The proposed VIPs possessed not only a low total thermal conductivity (at 100–100,000 Pa) in between that of glassfiber-VIPs and opacified FS-VIPs but also a much longer service life than glassfiber-VIPs. The addition of 36 wt.% RHA resulted in a 32% reduction in the cost of HCMs, while still maintaining its super Insulation capability. The optimum RHA content that led to a low-cost and highly thermal efficient VIP was 26–36 wt.%.
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thermo physical properties of polyester fiber reinforced fumed silica hollow glass microsphere composite core and resulted Vacuum Insulation Panel
Energy and Buildings, 2016Co-Authors: Cheng Dong Li, Teng Zhou Xu, Binbin Li, Muhammad Umar Saeed, Zhaofeng Chen, Yong YangAbstract:Abstract In recent years, various fiber/powder hybrid core materials (HCMs) are increasingly used as VIP core. In this paper, novel HCMs from mixtures of fumed silica (FS), hollow glass microsphere (HGM), polyester chopped strand fibers, titanium dioxide and carbon black powders were successfully fabricated by the dry powder mixing method. The effect of various HGM fractions on the thermo-physical properties of the HCMs and resulted VIPs was investigated. The HCMs possessed an excellent porous structure with a high porosity of 80–90% and a fine average pore size of 19.0–181.1 nm while the corresponding VIPs had a low density of 170–298 kg/m3. HGM additions led to a shift in the average pore diameter of HCMs toward a finer value and more concentrated distribution but posed an increase on specific surface area of the HCMs. Both the compression and rebound ratio of the VIPs were greatly reduced by adding HGMs in FS matrix. Total thermal conductivity versus air pressure (from 0.1 Pa to 1.013 × 105 Pa) curves of the HCMs with various HGM contents and the contributions of gaseous, solid, and radiative thermal conductivity on total thermal conductivity of the HCMs were conducted, respectively. The results showed that the total thermal conductivity of VIPs increased with the HGM addition but could maintain at a low value of less than 7.2 mW/(m K) when HGM content was less than 26 wt.%. HCMs with 6 wt.% HGM were recommended for VIPs in refrigeration while that with 26 wt.% HGM were recommended for VIPs in building sectors.
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configured cavity core matrix for Vacuum Insulation Panel concept preparation and thermophysical properties
Energy and Buildings, 2015Co-Authors: Fred Edmond Boafo, Jun-tae Kim, Zhaofeng ChenAbstract:Abstract Energy efficiency of buildings can be improved by implementing strategies to develop the building envelope components. Thermal Insulation of buildings has become vital, to attenuate energy demands for space heating and cooling. Presently Vacuum Insulation Panel (VIP) is regarded as a high performance thermal Insulation material. VIP enables efficient Insulation solutions in systems such as refrigerators, controlled thermal packages and buildings. For building applications, it is imperative to minimize material defects and to ensure thermal comfort. However, these Panels typically use spacers that cause a significant thermal bridge and undesirable gas permeation through spacer hole seal area. This study introduces an unconventional VIP, labeled as cavity-core matrix VIP; solving the aforementioned technical issue related to VIP application in buildings. The cavity-core matrix VIP was composed of glass fiber core material, and laminated aluminum foil envelope material. Owing to interlocking surface topology, bond strength increased by nearly 50% magnitude; considering the limitations specified. The estimated equivalent thermal conductivity of the optimized cavity-core matrix VIP was about 4.8 mW/(m K). The preparation processes, thermo-physical properties and challenges of cavity-core matrix VIP were discussed. The concept and exposition examined will enable building engineers and manufacturers to create thermally well performing and structurally adapted VIPs.
