This page has only limited features, please log in for full access.
Nowadays, new generations of building envelope need to manage the energy exchange between outdoor and indoor environment responsively and save the building energy. A significant amount of solar heat gain in buildings comes through the windows. The transparent envelope also must answer to visual requirements allowing for external vision but guarantying comfort conditions. In this framework, this article aims to test numerically the thermal performance of a new design of multifunctional glazed window combining the most recent technologies used in building envelopes. Five distinct window designs combing phase change material (PCM), vacuum glazing (VG), photovoltaic (PV), and air cavity were numerically tested for hot weather conditions. The proposed window designs slide inside the wall of the building. A comprehensive transient Multiphysics model coupling the thermo-electric model of the PV, melting and solidification model of the PCM, and the heat transfer mechanisms in the vacuum and air gaps are developed. The model is step by step validated with data in the literature. Various PCM types and PCM thickness are investigated. Among the five investigated window designs, the result showed that the window, including the air gap with PV, PCM cavity, and VG, is the optimal design for the indoor air's thermal isolation. Simultaneously, the PCM with a melting point of 35 ˚C and thickness of 50 mm is the best performance material in a hot arid region in summer at Cairo. The proposed multifunction window generated maximum electrical power intensity of 162 W/m2 at received solar radiation of 1000 W/m2.
Mostafa M.S. Ahmed; Ali Radwan; Ahmed A. Serageldin; Ahmed Abdeen; Essam M. Abo-Zahhad; Katsunori Nagano. The thermal potential of a new multifunctional sliding window. Solar Energy 2021, 226, 389 -407.
AMA StyleMostafa M.S. Ahmed, Ali Radwan, Ahmed A. Serageldin, Ahmed Abdeen, Essam M. Abo-Zahhad, Katsunori Nagano. The thermal potential of a new multifunctional sliding window. Solar Energy. 2021; 226 ():389-407.
Chicago/Turabian StyleMostafa M.S. Ahmed; Ali Radwan; Ahmed A. Serageldin; Ahmed Abdeen; Essam M. Abo-Zahhad; Katsunori Nagano. 2021. "The thermal potential of a new multifunctional sliding window." Solar Energy 226, no. : 389-407.
Radiant heating/cooling systems are thermally efficient and economically feasible alternatives to conventional ventilated air conditioning. This study experimentally investigates the thermal performance of the ceiling radiant cooling panel (CRCP) with a segmented and concave surface by evaluating the thermal conditions inside a laboratory-scale room equipped with this new panel. The experiments were carried out under various operating conditions, where the fluid inlet temperature and fluid flow rate were controlled independently. The indoor air temperature, air velocity, and humidity ratio were recorded and analyzed, and the temperatures of the upper and lower panel surfaces and the surrounding surfaces were also measured. Subsequently, the heat transfer properties were calculated and summarized. When the inlet water temperature decreased from 24 °C to 15 °C at the same flow rate of 4 L/min, the average air temperature decreased by over 1.5 °C, and the total heat flux increased by 50%. The heat flux changed significantly with variations in the inlet water temperature, while changing the flow rate had a smaller impact. The radiant heat transfer coefficient of the panel was determined to be 5.0 W/(m2·K), while the convective heat transfer coefficient exhibited an exponential relationship with the temperature difference between the surface of the panel and the surrounding air. Moreover, the proposed panel enhanced the convective heat flux by 2.6 times and the total heat flux by 45%, compared with a flat panel, and achieve the same improvement as the panel with inclined fins, but with a smaller surface area. In addition, the panel achieved the same air temperature with a lower flow rate, which shows the potential for energy saving.
Minzhi Ye; Ahmed A. Serageldin; Ali Radwan; Hideki Sato; Katsunori Nagano. Thermal performance of ceiling radiant cooling panel with a segmented and concave surface: laboratory analysis. Applied Thermal Engineering 2021, 196, 117280 .
AMA StyleMinzhi Ye, Ahmed A. Serageldin, Ali Radwan, Hideki Sato, Katsunori Nagano. Thermal performance of ceiling radiant cooling panel with a segmented and concave surface: laboratory analysis. Applied Thermal Engineering. 2021; 196 ():117280.
Chicago/Turabian StyleMinzhi Ye; Ahmed A. Serageldin; Ali Radwan; Hideki Sato; Katsunori Nagano. 2021. "Thermal performance of ceiling radiant cooling panel with a segmented and concave surface: laboratory analysis." Applied Thermal Engineering 196, no. : 117280.
This paper proposes a novel spiral-double ground heat exchanger (GHX) that decreases conventional construction costs, facilitates installation, promotes heat transfer, and reduces thermal resistance. In this study, a new and effective installation procedure was proposed. Three-dimensional, transient, and conjugated finite volume simulations were conducted to compare the thermo-hydraulic performance of the traditional single U-tube and spiral GHXs with the proposed spiral-double GHX under two different flow rates. Moreover, a parametric analysis was conducted to study the impact of the design, operating, and geological parameters on the thermal performance of the new spiral-double GHX. Finally, surface response and sensitivity analyses, as well as optimization, were carried out using the ANSYS workbench. The comparison revealed that the spiral-double GHX yields higher thermal effectiveness (E) and heat transfer rate (Q) than single-U tubes GHX by 40.8% and 44.1%, respectively. In addition, it has a lower thermal resistance of 75.3% than the single-U tube GHX under turbulent flow conditions. Furthermore, the parametric study and sensitivity analysis concluded that the spiral radius has the most significant impact, followed by flow velocity, tube diameter, and pitch distance. Moreover, the recommended fluid velocity does not exceed 0.21 m/s, pitch distance of 0.0625 m, a spiral radius of 0.2 m, and grout conductivity of 2.1 W/m.K.
Ahmed A. Serageldin; Ali Radwan; Takao Katsura; Yoshitaka Sakata; Shigeyuki Nagasaka; Katsunori Nagano. Parametric analysis, response surface, sensitivity analysis, and optimization of a novel spiral-double ground heat exchanger. Energy Conversion and Management 2021, 240, 114251 .
AMA StyleAhmed A. Serageldin, Ali Radwan, Takao Katsura, Yoshitaka Sakata, Shigeyuki Nagasaka, Katsunori Nagano. Parametric analysis, response surface, sensitivity analysis, and optimization of a novel spiral-double ground heat exchanger. Energy Conversion and Management. 2021; 240 ():114251.
Chicago/Turabian StyleAhmed A. Serageldin; Ali Radwan; Takao Katsura; Yoshitaka Sakata; Shigeyuki Nagasaka; Katsunori Nagano. 2021. "Parametric analysis, response surface, sensitivity analysis, and optimization of a novel spiral-double ground heat exchanger." Energy Conversion and Management 240, no. : 114251.
The warm draft that floats from the window has an unfavorable influence on the indoor thermal comfort condition, which heated the indoor air temperature. Therefore, an integrated cooling system combined novel free-suspended ceiling radiant cooling panel (CRCP) with a wall Attached Ventilation (WAV) system is proposed and investigated by using a three-dimensional conjugated computational fluid dynamic (CFD). Two different WAV systems (ceiling inlet/ceiling outlet; ceiling inlet/floor outlet) are examined under various operating conditions. Moreover, the surface response, sensitivity analysis, and optimization of the system's operating condition are carried out via the ANSYS Design Explorer tool. In conclusion, adding the ventilation system with a ceiling inlet and ceiling outlet is more effective than installing a ceiling inlet and a floor outlet. Moreover, the operating conditions with the inlet air velocity of 0.164 m/s, inlet air temperature of 25 °C, and panel surface temperature of 23 °C are selected as the optimum design. Under this condition, the system can prevent warm draft effectively and achieve better thermal comfort using a lower ventilation flow rate, higher ventilation temperature, and higher panel surface temperatures. Thus, it also shows a significant potential of energy-saving accordingly.
Minzhi Ye; Ahmed A. Serageldin; Katsunori Nagano. Numerical optimization of a novel ceiling radiant cooling panel combined with wall attached ventilation system. Case Studies in Thermal Engineering 2021, 26, 101066 .
AMA StyleMinzhi Ye, Ahmed A. Serageldin, Katsunori Nagano. Numerical optimization of a novel ceiling radiant cooling panel combined with wall attached ventilation system. Case Studies in Thermal Engineering. 2021; 26 ():101066.
Chicago/Turabian StyleMinzhi Ye; Ahmed A. Serageldin; Katsunori Nagano. 2021. "Numerical optimization of a novel ceiling radiant cooling panel combined with wall attached ventilation system." Case Studies in Thermal Engineering 26, no. : 101066.
Radiant cooling/heating (RCH) panel systems have recently received increasing attention because of their energy-efficient operation and improved comfort performance. Therefore, this study proposes a novel RCH panel with segmented concave surfaces. The new panel has the same surface area as a conventional flat surface panel. A series of laboratory tests were conducted to investigate the heat transfer characteristics inside a chamber equipped with the new panel. Moreover, a three-dimensional finite volume simulation was developed to investigate the heat transfer, fluid flow, and thermal comfort conditions inside a single room equipped with the proposed panel, and the results were compared with those of a conventional flat surface panel under the same operating conditions and cooling load. First, the curvature cord length ratio to curvature radius (L/R) was optimized in the range of 0 (flat) to 2. In all cases, the surface area was the same, but the coverage area ratio varied. In addition, the impact of different coverage area ratios from 55% to 81% and the influence of adding void spaces of 29 mm and 11 mm between adjacent curved segments were analyzed. The results showed that the simulation achieved good agreement with the experimental results with an accuracy of 98.9%. The coverage area ratio played an essential role in decreasing the indoor air temperature by 2 °C and reducing the floor temperature by 1.6 °C. When the L/R ratio changed from 0 to 1.5 at a coverage ratio of 81%, the average air temperature decreased by 1 ºC. Moreover, increasing the L/R ratio from 0 to 2 with void spaces of 2.9 mm and 11 mm reduced the radiation heat transfer coefficient, hr, by 31%, while the convection heat transfer coefficient, hc, at the panel upper surface increased by 174%. Changing only the panel surface shape from flat to concave and segmented enhanced the thermal performance and thermal comfort inside the indoor environment.
Ahmed A. Serageldin; Minzhi Ye; Ali Radwan; Hideki Sato; Katsunori Nagano. Numerical investigation of the thermal performance of a radiant ceiling cooling panel with segmented concave surfaces. Journal of Building Engineering 2021, 42, 102450 .
AMA StyleAhmed A. Serageldin, Minzhi Ye, Ali Radwan, Hideki Sato, Katsunori Nagano. Numerical investigation of the thermal performance of a radiant ceiling cooling panel with segmented concave surfaces. Journal of Building Engineering. 2021; 42 ():102450.
Chicago/Turabian StyleAhmed A. Serageldin; Minzhi Ye; Ali Radwan; Hideki Sato; Katsunori Nagano. 2021. "Numerical investigation of the thermal performance of a radiant ceiling cooling panel with segmented concave surfaces." Journal of Building Engineering 42, no. : 102450.
The variability of ground thermal conductivity, based on underground conditions, is often ignored during the design of ground-source heat pump systems. This study shows a field evidence of such site-scale variations through thermal response tests in eight borehole heat exchangers aligned at a site on a terrace along the foothills of mountains in northern Japan. Conventional analysis of the overall ground thermal conductivity along the total installation length finds that the value at one borehole heat exchanger is 2.5 times that at the other seven boreholes. History matching analysis of underground distributed temperature measurements generates vertical partial ground thermal conductivity data for four depth layers. Based on the moving line heat source theory, the partial values are generally within a narrow range expected for gravel deposits. Darcy velocities of groundwater are estimated to be 74–204 m/y at the borehole with high conductivity, increasing in the shallow layers above a depth of 41 m. In contrast, the velocities at the other seven boreholes are one-to-two orders of magnitude smaller with no trend. These high and low velocity values are considered for the topography and permeability. However, the relatively slow groundwater velocities might not apparently increase the partial conductivity.
Yoshitaka Sakata; Takao Katsura; Ahmed Serageldin; Katsunori Nagano; Motoaki Ooe. Evaluating Variability of Ground Thermal Conductivity within a Steep Site by History Matching Underground Distributed Temperatures from Thermal Response Tests. Energies 2021, 14, 1872 .
AMA StyleYoshitaka Sakata, Takao Katsura, Ahmed Serageldin, Katsunori Nagano, Motoaki Ooe. Evaluating Variability of Ground Thermal Conductivity within a Steep Site by History Matching Underground Distributed Temperatures from Thermal Response Tests. Energies. 2021; 14 (7):1872.
Chicago/Turabian StyleYoshitaka Sakata; Takao Katsura; Ahmed Serageldin; Katsunori Nagano; Motoaki Ooe. 2021. "Evaluating Variability of Ground Thermal Conductivity within a Steep Site by History Matching Underground Distributed Temperatures from Thermal Response Tests." Energies 14, no. 7: 1872.
In this research, automatic fouling cleaning systems that clean and prevent the deposit of fouling by regularly circulating sponge or ceramic balls are proposed. Characteristics of the finned and twisted inner tubes of the double pipe heat exchanger for the heat pump unit are also compared. Lastly, the 50RT-scale field test of the automatic fouling cleaning system integrated with the heat pump system was conducted by targeting temperature control of fish farms. The finned inner tube types presented a higher heat transfer rate than that of the twisted inner tube types. For the finned tube types, the refrigerant supply from the tangential direction was more advantageous due to the uniform distribution of refrigerant into 16 channels. The twisted tubes showed a higher water pressure drop than the finned inner tubes. An obvious increase in the fouling factor according to the operating hours was observed; however, it could be successfully decreased by operating the fouling cleaning system for 24 h. The overall heat transfer coefficient could be recovered from 5.87 kW/K to 24.05 kW/K, which is about 92% of the initial value. In short, the automatic fouling cleaning system can successfully prevent performance degradation of heat pump system due to fouling.
Sung-Hoon Seol; Ahmed A. Serageldin; Oh Kyung Kwon. Experimental Research on a Heat Pump Applying a Ball-Circulating Type Automatic Fouling Cleaning System for Fish Farms. Energies 2020, 13, 5856 .
AMA StyleSung-Hoon Seol, Ahmed A. Serageldin, Oh Kyung Kwon. Experimental Research on a Heat Pump Applying a Ball-Circulating Type Automatic Fouling Cleaning System for Fish Farms. Energies. 2020; 13 (22):5856.
Chicago/Turabian StyleSung-Hoon Seol; Ahmed A. Serageldin; Oh Kyung Kwon. 2020. "Experimental Research on a Heat Pump Applying a Ball-Circulating Type Automatic Fouling Cleaning System for Fish Farms." Energies 13, no. 22: 5856.
A zero-energy building (ZEB) requires an innovative integration of technologies, in which windows play a paramount role in energy reduction, storage, and generation. This study contributes to four innovative designs of sliding smart windows. It integrates air-gap (AG), phase change material (PCM), photovoltaic (PV), and vacuum glazing (VG) technologies. These smart sliding windows are proposed to generate electricity along with achieving efficient thermal insulations and heat storage simultaneously. A two-dimensional multiphysics thermal model that couples the PCM melting and solidification model, PV model, natural convection in the cavity, and the surface-to-surface radiation model in the vacuum gap are developed for the first time. The model is validated with data in the literature. The transient simulations were carried out to investigate the thermo-electrical performance of a window with an area of 1 m by 1 m for the meteorological conditions of Kuwait city on the 10th of June 2018, where the window was oriented to south direction. The results showed that the total solar heat energy gain per unit window area is 2.6 kWh, 0.02 kWh, 0.22 kWh, 1.48 kWh, and 0.2 kWh for the double AG, AG + PV + PCM + VG, PV + PCM + VG, AG + PV + PCM, and the ventilated AG + PV + PCM + VG, respectively. The results elucidate the advantages of the integration of VG in this integrated sliding smart window. The daily generated PV electrical energy in these systems is around 1.3 kWh, 1.43 kWh, and 1.38 kWh for the base case with double AG, PV + PCM + VG, and the ventilated AG + PV + PCM + VG respectively per unit window area.
Mostafa Ahmed; Ali Radwan; Ahmed Serageldin; Saim Memon; Takao Katsura; Katsunori Nagano. Thermal Analysis of a New Sliding Smart Window Integrated with Vacuum Insulation, Photovoltaic, and Phase Change Material. Sustainability 2020, 12, 7846 .
AMA StyleMostafa Ahmed, Ali Radwan, Ahmed Serageldin, Saim Memon, Takao Katsura, Katsunori Nagano. Thermal Analysis of a New Sliding Smart Window Integrated with Vacuum Insulation, Photovoltaic, and Phase Change Material. Sustainability. 2020; 12 (19):7846.
Chicago/Turabian StyleMostafa Ahmed; Ali Radwan; Ahmed Serageldin; Saim Memon; Takao Katsura; Katsunori Nagano. 2020. "Thermal Analysis of a New Sliding Smart Window Integrated with Vacuum Insulation, Photovoltaic, and Phase Change Material." Sustainability 12, no. 19: 7846.
A new practical method for thermal response test (TRT) is proposed herein to estimate the groundwater velocity and effective thermal conductivity of geological zones. The relaxation time of temperature (RTT) is applied to determine the depths of the zones. The RTT is the moment when the temperature in the borehole recovers to a certain level compared with that when the heating is stopped. The heat exchange rates of the zones are calculated from the vertical temperature profile measured by the optical-fiber distributed temperature sensors located in the supply and return sides of a U-tube. Finally, the temperature increments at the end time of the TRT are calculated according to the groundwater velocities and the effective thermal conductivity using the moving line source theory applied to the calculated heat exchange rates. These results are compared with the average temperature increment data measured from each zone, and the best-fitting value yields the groundwater velocities for each zone. Results show that the groundwater velocities for each zone are 2750, 58, and 0 m/y, whereas the effective thermal conductivities are 2.4, 2.4, and 2.1 W/(m∙K), respectively. The proposed methodology is evaluated by comparing it with the realistic long-term operation data of a ground source heat pump (GSHP) system in Kazuno City, Japan. The temperature error between the calculated results and measured data is 6.4% for two years. Therefore, the proposed methodology is effective for estimating the long-term performance analysis of GSHP systems.
Hobyung Chae; Katsunori Nagano; Yoshitaka Sakata; Takao Katsura; Ahmed A. Serageldin; Takeshi Kondo. Analysis of Relaxation Time of Temperature in Thermal Response Test for Design of Borehole Size. Energies 2020, 13, 3297 .
AMA StyleHobyung Chae, Katsunori Nagano, Yoshitaka Sakata, Takao Katsura, Ahmed A. Serageldin, Takeshi Kondo. Analysis of Relaxation Time of Temperature in Thermal Response Test for Design of Borehole Size. Energies. 2020; 13 (13):3297.
Chicago/Turabian StyleHobyung Chae; Katsunori Nagano; Yoshitaka Sakata; Takao Katsura; Ahmed A. Serageldin; Takeshi Kondo. 2020. "Analysis of Relaxation Time of Temperature in Thermal Response Test for Design of Borehole Size." Energies 13, no. 13: 3297.
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.
Ali Radwan; Takao Katsura; Saim Memon; Ahmed A. Serageldin; Makoto Nakamura; Katsunori Nagano. Thermal and electrical performances of semi-transparent photovoltaic glazing integrated with translucent vacuum insulation panel and vacuum glazing. Energy Conversion and Management 2020, 215, 112920 .
AMA StyleAli Radwan, Takao Katsura, Saim Memon, Ahmed A. Serageldin, Makoto Nakamura, Katsunori Nagano. Thermal and electrical performances of semi-transparent photovoltaic glazing integrated with translucent vacuum insulation panel and vacuum glazing. Energy Conversion and Management. 2020; 215 ():112920.
Chicago/Turabian StyleAli Radwan; Takao Katsura; Saim Memon; Ahmed A. Serageldin; Makoto Nakamura; Katsunori Nagano. 2020. "Thermal and electrical performances of semi-transparent photovoltaic glazing integrated with translucent vacuum insulation panel and vacuum glazing." Energy Conversion and Management 215, no. : 112920.
A new-shaped U-tube with an oval cross-section has been developed to boost the heat transfer inside the borehole heat exchanger and to reduce the heat exchanger depth and the drilling cost. In addition, it could fit efficiently inside tight boreholes, so it is fitting for installing GSHPs at urban areas. This research evaluated the effectiveness in situ by thermal response tests at total 20 borehole heat exchangers in three sites, Japan. The in situ borehole thermal resistances were about 10–30% smaller with the oval U-tube than the circle U-tube. However, the spacers had an imperceptible impact probably because of the soil pressure to the U-tubes. Also, transient numerical CFD simulations were carried out to calculate the long-term performance of a household GSHP system with oval U-tubes. It indicated that the required lengths of a borehole heat exchanger could be reduced by about 14% in the fine soils and 15–19% in the coarse soils.
Yoshitaka Sakata; Ahmed A. Serageldin; Takao Katsura; Motoaki Ooe; Katsunori Nagano. Evaluating Thermal Performance of Oval U-Tube for Ground-Source Heat Pump Systems from in Situ Measurements and Numerical Simulations. Soil and Recycling Management in the Anthropocene Era 2020, 1483 -1491.
AMA StyleYoshitaka Sakata, Ahmed A. Serageldin, Takao Katsura, Motoaki Ooe, Katsunori Nagano. Evaluating Thermal Performance of Oval U-Tube for Ground-Source Heat Pump Systems from in Situ Measurements and Numerical Simulations. Soil and Recycling Management in the Anthropocene Era. 2020; ():1483-1491.
Chicago/Turabian StyleYoshitaka Sakata; Ahmed A. Serageldin; Takao Katsura; Motoaki Ooe; Katsunori Nagano. 2020. "Evaluating Thermal Performance of Oval U-Tube for Ground-Source Heat Pump Systems from in Situ Measurements and Numerical Simulations." Soil and Recycling Management in the Anthropocene Era , no. : 1483-1491.
New small-scale experiments are carried out to study the effect of groundwater flow on the thermal performance of water ground heat exchangers for ground source heat pump systems. Four heat exchanger configurations are investigated; single U-tube with circular cross-section (SUC), single U-tube with an oval cross-section (SUO), single U-tube with circular cross-section and single spacer with circular cross-section (SUC + SSC) and single U-tube with an oval cross-section and single spacer with circular cross-section (SUO + SSC). The soil temperature distributions along the horizontal and vertical axis are measured and recorded simultaneously with measuring the electrical energy injected into the fluid, and the borehole wall temperature is measured as well; consequently, the borehole thermal resistance (Rb) is calculated. Moreover, two dimensional and steady-state CFD simulations are validated against the experimental measurements at the groundwater velocity of 1000 m/year with an average error of 3%. Under saturated conditions without groundwater flow effect; using a spacer with SUC decreases the Rb by 13% from 0.15 m·K/W to 0.13 m·K/W, also using a spacer with the SUO decreases the Rb by 9% from 0.11 m·K/W to 0.1 m·K/W. In addition, the oval cross-section with spacer SUO + SSC decreases the Rb by 33% compared with SUC. Under the effect of groundwater flow of 1000 m/year; Rb of the SUC, SUO, SUC + SSC and SUO + SSC cases decrease by 15.5%, 12.3%, 6.1% and 4%, respectively, compared with the saturated condition.
Ahmed A. Serageldin; Ali Radwan; Yoshitaka Sakata; Takao Katsura; Katsunori Nagano. The Effect of Groundwater Flow on the Thermal Performance of a Novel Borehole Heat Exchanger for Ground Source Heat Pump Systems: Small Scale Experiments and Numerical Simulation. Energies 2020, 13, 1418 .
AMA StyleAhmed A. Serageldin, Ali Radwan, Yoshitaka Sakata, Takao Katsura, Katsunori Nagano. The Effect of Groundwater Flow on the Thermal Performance of a Novel Borehole Heat Exchanger for Ground Source Heat Pump Systems: Small Scale Experiments and Numerical Simulation. Energies. 2020; 13 (6):1418.
Chicago/Turabian StyleAhmed A. Serageldin; Ali Radwan; Yoshitaka Sakata; Takao Katsura; Katsunori Nagano. 2020. "The Effect of Groundwater Flow on the Thermal Performance of a Novel Borehole Heat Exchanger for Ground Source Heat Pump Systems: Small Scale Experiments and Numerical Simulation." Energies 13, no. 6: 1418.
With the increasing number of migrants and refugees, there is a need for energy-efficient and low impact temporary housing that can accommodate millions of displaced peoples worldwide. This study describes a design proposal for a premium passive refugee house that uses three main passive heating and cooling solutions (Earth Air Heat Exchanger, Trombe wall, and green wall) and is suited to the Swedish climate. The purpose of the combination of the three passive systems is to reduce cooling and heating loads to conserve a significant amount of primary energy and thus mitigate the impact of the house’s energy use on the environment through a reduction in emissions. The house is designed to fulfill its energy needs from renewable sources and produce an annual surplus of 180 kWh/m2/annum. The methodology applied is a dynamic system modeling and simulation approach using TRNSYS and ANSYS software. The simulation results showed a heating load of 7.9 kWh/m2/annum and a cooling load of 2.8 kWh/m2/annum, with total energy consumption reaching 18.4 kWh/m2/annum. Preliminary feasibility costing showed a payback time of 7.4 years out of the 25-years suggested lifetime of building using the three passive solutions. The amount of CO2 emissions is 231.1 kg CO2e/annum with a primary energy demand of 0.032 GJ/m2/annum. As a follow-up to the initial study, a proof of concept has been implemented in Lund, Sweden, in an urban living lab to verify the simulation results through a 12-month post-occupancy monitoring and evaluation study.
Marwa Dabaieh; Ahmed A. Serageldin. Earth air heat exchanger, Trombe wall and green wall for passive heating and cooling in premium passive refugee house in Sweden. Energy Conversion and Management 2020, 209, 112555 .
AMA StyleMarwa Dabaieh, Ahmed A. Serageldin. Earth air heat exchanger, Trombe wall and green wall for passive heating and cooling in premium passive refugee house in Sweden. Energy Conversion and Management. 2020; 209 ():112555.
Chicago/Turabian StyleMarwa Dabaieh; Ahmed A. Serageldin. 2020. "Earth air heat exchanger, Trombe wall and green wall for passive heating and cooling in premium passive refugee house in Sweden." Energy Conversion and Management 209, no. : 112555.
In this study, evaluation and performance investigation of new three different configurations, for sea water desalination system using two identical Ranque-Hilsch vortex tubes (RHVT) is carried out. The new technique for water desalination is developed using various series and parallel vortex tubes configurations, instead of single vortex tube integrated desalination system, two series RHVTs using the hot air stream of the first tube as the air source of the second one is called series hot vortex tubes (SHVT) configuration, another configuration was two series RHVTs using the cold air steam of the first tube as the air source of the second one, is called series cold vortex tubes (SCVT) configuration, the third one was two parallel RHVTs collecting both hot air steams of the two tubes from one side and collecting both cold air steams of the two tube from the other side, and is called parallel vortex tubes (PVT) configuration. The main study conclusions are deduced that, the desalinated water quantity reached about 79% of the initial sea water quantity for SHVT arrangement, otherwise, it was about only 70% for SCVT arrangement and 74% for PVT arrangement. Furthermore, the results of this work could help to adopt more efficient desalination systems based on using RHVTs, and the SHVT configuration can be strongly recommended for use in seawater desalination.
Ahmed Nagah Shmroukh; Ali Radwan; Abdalla Abdal-Hay; Ahmed A. Serageldin; Mahmoud Nasr. New configurations for sea water desalination system using Ranque-Hilsch vortex tubes. Applied Thermal Engineering 2019, 157, 113757 .
AMA StyleAhmed Nagah Shmroukh, Ali Radwan, Abdalla Abdal-Hay, Ahmed A. Serageldin, Mahmoud Nasr. New configurations for sea water desalination system using Ranque-Hilsch vortex tubes. Applied Thermal Engineering. 2019; 157 ():113757.
Chicago/Turabian StyleAhmed Nagah Shmroukh; Ali Radwan; Abdalla Abdal-Hay; Ahmed A. Serageldin; Mahmoud Nasr. 2019. "New configurations for sea water desalination system using Ranque-Hilsch vortex tubes." Applied Thermal Engineering 157, no. : 113757.
With the increasing effort to find alternative energy applications, solar energy for the heating of dwellings has been attracting much attention recently. The Trombe wall, which relies on the natural convection and energy storage of its massive thermal wall, is an effective technique to utilize solar energy to decrease the heating load in a building throughout the winter season. In this study, the heat transfer processes and air flow in a Trombe wall were investigated mathematically and numerically, combined with experimental validation. A simplified analytical model of a Trombe wall was developed, with the overall energy balance under quasi-state conditions taken into consideration for a typical winter week in Alexandria, Egypt. With this model, a broad range of geometric parameters was examined to determine the optimal design for a Trombe wall in terms of enhancing the thermal comfort. The optimal Trombe wall derived from the mathematical model, featuring a height of 1.7 m, thickness of 0.3 m for the massive wall, and with a channel depth of 0.22 m. This model could improve the thermal comfort by 38.19% during a typical winter week. Additionally, using DesignBuilder software, thermal and computational fluid dynamics (CFD) calculations were carried out to simulate the proposed Trombe wall design during the entire winter and to predict the space flow pattern in detail, respectively. We achieved reasonable agreement between the mathematical model predictions and the CFD calculations, as well as the experimental results.
Ahmed Abdeen; Ahmed Serageldin; Mona G.E. Ibrahim; Abbas El-Zafarany; Shinichi Ookawara; Ryo Murata. Experimental, analytical, and numerical investigation into the feasibility of integrating a passive Trombe wall into a single room. Applied Thermal Engineering 2019, 154, 751 -768.
AMA StyleAhmed Abdeen, Ahmed Serageldin, Mona G.E. Ibrahim, Abbas El-Zafarany, Shinichi Ookawara, Ryo Murata. Experimental, analytical, and numerical investigation into the feasibility of integrating a passive Trombe wall into a single room. Applied Thermal Engineering. 2019; 154 ():751-768.
Chicago/Turabian StyleAhmed Abdeen; Ahmed Serageldin; Mona G.E. Ibrahim; Abbas El-Zafarany; Shinichi Ookawara; Ryo Murata. 2019. "Experimental, analytical, and numerical investigation into the feasibility of integrating a passive Trombe wall into a single room." Applied Thermal Engineering 154, no. : 751-768.
Ahmed Abdeen; Ahmed Serageldin; Mona Ibrahim; Abbas El-Zafarany; Shinichi Ookawara; Ryo Murata. Solar chimney optimization for enhancing thermal comfort in Egypt: An experimental and numerical study. Solar Energy 2019, 180, 524 -536.
AMA StyleAhmed Abdeen, Ahmed Serageldin, Mona Ibrahim, Abbas El-Zafarany, Shinichi Ookawara, Ryo Murata. Solar chimney optimization for enhancing thermal comfort in Egypt: An experimental and numerical study. Solar Energy. 2019; 180 ():524-536.
Chicago/Turabian StyleAhmed Abdeen; Ahmed Serageldin; Mona Ibrahim; Abbas El-Zafarany; Shinichi Ookawara; Ryo Murata. 2019. "Solar chimney optimization for enhancing thermal comfort in Egypt: An experimental and numerical study." Solar Energy 180, no. : 524-536.
A parametric analysis and optimization method for passive heating and ventilation systems are developed, using the computational fluid dynamics (CFD) ANSYS design exploration and optimization tool. Moreover, a three-dimensional, quasi-steady CFD Fluent simulation is performed and validated against experimental results. For comparison, the thermal performance of a small-scale wooden room fitted with a solar chimney and an earth-to-air heat exchanger (EAHE) was experimentally evaluated in the cold season in Egypt, in March 14–22, 2016. A good agreement has been found between the experimental and simulated results, with error, correlation coefficient, and coefficient of determination average values of 7.3%, 96.5%, and 94%, respectively. Moreover, a parametric study is conducted to maximize the ventilation rate, using eight parameters for solar chimney configuration (width, length, air gap, inclination angle, and position) and EAHE design (pipe diameter, inlet position, and inlet height). It is found that the EAHE pipe diameter is the most sensitive parameter, followed by chimney height, and EAHE inlet height and position; the solar chimney inclination angle, width, and gap have also noticeable impacts. The optimum chimney inclination angle, length, width, and gap ranges are 30–35°, 1.94–1.97 m, 0.92–0.97 m, and 0.19–0.23 m, respectively.
Ahmed A. Serageldin; Ali K. Abdelrahman; Shinichi Ookawara. Parametric study and optimization of a solar chimney passive ventilation system coupled with an earth-to-air heat exchanger. Sustainable Energy Technologies and Assessments 2018, 30, 263 -278.
AMA StyleAhmed A. Serageldin, Ali K. Abdelrahman, Shinichi Ookawara. Parametric study and optimization of a solar chimney passive ventilation system coupled with an earth-to-air heat exchanger. Sustainable Energy Technologies and Assessments. 2018; 30 ():263-278.
Chicago/Turabian StyleAhmed A. Serageldin; Ali K. Abdelrahman; Shinichi Ookawara. 2018. "Parametric study and optimization of a solar chimney passive ventilation system coupled with an earth-to-air heat exchanger." Sustainable Energy Technologies and Assessments 30, no. : 263-278.
In this paper, a novel U-tube Borehole Heat Exchanger (BHX) with an oval cross-section is proposed for improving the performance of Ground Source Heat Pump systems (GSHP). To study the thermo-hydraulic performance of Borehole Heat Exchanger (BHX) with an oval U-tube: A three-dimensional, symmetric and unsteady state multi-physics Computational Fluid Dynamic (CFD) simulations are carried out by ANSYS FLUENT environment. The conjugate heat transfer and fluid flow are simulated. Borehole thermal resistance, fluid inlet and outlet temperatures, fluid temperature profile along pipe length and pressure drop inside the tube are calculated and analyzed. The oval shape dimensions are adapted, then a comparison between the circle and the oval cross-sections is carried out; four different cases are investigated. As a result, the CFD results show a good agreement with their experimental pairs via Thermal Response Test (TRT) test which was done during September 2017 by our laboratory members. Besides, the results show that the oval shape enhances the heat transfer process and achieves the lowest borehole thermal resistance of 0.125 m K/W, also, it decreases the thermal resistance by 18.47% compared with the circular one. Besides, the oval shape shows a pressure drop of 32% less than the circular tube. Consequently, the oval shape could enhance the coefficient of performance (COP) of GSHP, decrease the borehole length, decrease the operating pressure and cut down initial and operating costs. Also, it fit easily inside tight borehole, so it is preferable in high-densely urban areas.
Ahmed A. Serageldin; Yoshitaka Sakata; Takao Katsura; Katsunori Nagano. Thermo-hydraulic performance of the U-tube borehole heat exchanger with a novel oval cross-section: Numerical approach. Energy Conversion and Management 2018, 177, 406 -415.
AMA StyleAhmed A. Serageldin, Yoshitaka Sakata, Takao Katsura, Katsunori Nagano. Thermo-hydraulic performance of the U-tube borehole heat exchanger with a novel oval cross-section: Numerical approach. Energy Conversion and Management. 2018; 177 ():406-415.
Chicago/Turabian StyleAhmed A. Serageldin; Yoshitaka Sakata; Takao Katsura; Katsunori Nagano. 2018. "Thermo-hydraulic performance of the U-tube borehole heat exchanger with a novel oval cross-section: Numerical approach." Energy Conversion and Management 177, no. : 406-415.
In this paper, the thermal performance of an Earth-Air Heat Exchanger (EAHE) used for heating and cooling purposes is investigated under Egyptian weather conditions. The soil temperature profile and the temperature distribution of flowing air through horizontal Earth-Air Heat Exchanger (EAHE) is experimentally studied. Also, a mathematical model based on unsteady, one-dimensional and quasi-state is developed for energy conservation equation. Moreover, an explicit finite difference numerical method is used to solve the developed mathematical model with the help of MATLAB code. Finally, three-dimensional, steady and double precision Computational Fluid Dynamics (CFD) ANSYS Fluent simulation model is established to predict the air and soil temperature. Whereas, the standard κ-∈κ-∈ model is applied to simulate the turbulence kinetic energy of the flowing fluid. The mathematically developed model and CFD simulation result validated against experimental results. Good agreement is achieved with an average error and correlation coefficient of 2.09, 97% and 3.3 and 95.5% for CFD simulation and mathematical model respectively. The CFD model is used in a parametric investigation. A parametric study carried out to explore the impact of different parameters such as pipe diameter, pipe material, pipe space, pipe length and flowing fluid velocity. The results show that some of these parameters have noticeable results in air temperature. Whereas, the pipe diameter increases the air temperature decreases. The outlet air temperature declines from 20.4 °C to 18.7 °C as the pipe diameter expands from 2 to 3 in. Furthermore, as pipe length increases, outlet air temperature enhances. The temperature changes from 19.7 to 19.9 °C as the pipe length elongates from 5.45 m to 7 m. A bit change occurs in outlet air temperature from 19.7 °C to 19.8 °C when pipe space changes from 0.2 to 0.5 m. Moreover, three different pipe materials such as PVC, steel and copper are implied. The outlet air temperature was 19.7 °C in PVC pipe and 19.8, 19.8 °C for steel and copper respectively. So the conclusion is that the change in outlet air temperature for various pipe material is neglected compared with their prices. Finally, the effect of fluid velocity was investigated. Therefore, the outlet air temperature declines from 20.4 °C to 19.2 °C as air accelerates from 1 to 3 m/s.
Ahmed A. Serageldin; Ali K. Abdelrahman; Shinichi Ookawara. Earth-Air Heat Exchanger thermal performance in Egyptian conditions: Experimental results, mathematical model, and Computational Fluid Dynamics simulation. Energy Conversion and Management 2016, 122, 25 -38.
AMA StyleAhmed A. Serageldin, Ali K. Abdelrahman, Shinichi Ookawara. Earth-Air Heat Exchanger thermal performance in Egyptian conditions: Experimental results, mathematical model, and Computational Fluid Dynamics simulation. Energy Conversion and Management. 2016; 122 ():25-38.
Chicago/Turabian StyleAhmed A. Serageldin; Ali K. Abdelrahman; Shinichi Ookawara. 2016. "Earth-Air Heat Exchanger thermal performance in Egyptian conditions: Experimental results, mathematical model, and Computational Fluid Dynamics simulation." Energy Conversion and Management 122, no. : 25-38.
This study investigated experimentally the effect of air born suspend matters deposition on PV module located in harsh climate close to the sea. The experimental measurements are carried out under outdoor conditions in Alexandria, Egypt to identify the module performance degradation as a function of time as well as the time schedule for module surface cleaning. However, as the sea is nearby it's a source for nocturnal condensate on module surface. The experiments were conducted during period from 13 March to 17 April, 2013. The results indicated that the dust accumulation on the module surface has a significant impact on PV module output power. As the dust deposition density increased from 0 to 0.36 mg cm -2 , the corresponding reduction of PV output efficiency as well as short circuit current I sc are degraded by 17.71%. Conversely, the reduction of open circuit voltage was insignificant where the maximum reduction of V oc from 100% to 97.86 of the clean module value. The average degradation of power and efficiency during the entire period of work (30 days) is 9.86%. Also the results show that the dust effect on thin film PV modules becomes most significant in cloudy weather day rather than clear day and the degradation in performance reaches about 16.01% in cloudy day.
Ahmed Serageldin; Ali K. Abel-Rahman; Ahmed Hamza H. Ali; S. Ookawara. Effect of dust deposition on performance of thin film photovoltaic module in harsh humid climate. 2013 International Conference on Renewable Energy Research and Applications (ICRERA) 2013, 674 -679.
AMA StyleAhmed Serageldin, Ali K. Abel-Rahman, Ahmed Hamza H. Ali, S. Ookawara. Effect of dust deposition on performance of thin film photovoltaic module in harsh humid climate. 2013 International Conference on Renewable Energy Research and Applications (ICRERA). 2013; ():674-679.
Chicago/Turabian StyleAhmed Serageldin; Ali K. Abel-Rahman; Ahmed Hamza H. Ali; S. Ookawara. 2013. "Effect of dust deposition on performance of thin film photovoltaic module in harsh humid climate." 2013 International Conference on Renewable Energy Research and Applications (ICRERA) , no. : 674-679.