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Dr. Ali Radwan
Mechanical Power Engineering, Faculty of Engineering, Mansoura University, Dakahlia Governorate 35516, Egypt

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Research Keywords & Expertise

0 Concentrated Solar Power
0 Thermoelectric generator
0 Solar Thermal Energy
0 Solar thermal collectors
0 Photovoltaic-thermal

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Photovoltaic-thermal
Vacuum insulation
Concentrated Solar Power
Thermoelectric generator

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Journal article
Published: 11 April 2021 in Solar Energy
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The concentrator photovoltaic (CPV) systems commonly endure high cell temperatures, which affect their overall performance. Besides, the high cell temperature could lead to physical damages within the whole system due to the induced thermal stresses. Therefore, an efficient cooling is mandatory to achieve a higher net output power from the CPV and safe operation. The current work's main purpose is to investigate the integration of double-layered microchannel heat sink (DL-MCHS) with CPV cell as thermal management device. A three-dimensional (3D) model is presented to investigate the performance of a CPV cooled by the DL-MCHS to figure out the ability to handle the effective heat dissipation under different terrestrial conditions. The parallel flow (PF) and counter flow (CF) cooling orientations were studied. Ethanol coolant is used to cool the CPV under different concentration ratios (CR) of 5, 10, 15, and 20 suns. The results show that the temperatures remarkably decreases with the inlet flowrate is increased. The counter flow operation (CF) achieved the best temperature uniformity index (Tuni) when the coolant mass flowrate (V̇) ranged between 200 and 1200 ml/hr. Especially at CR 5 suns, the temperature uniformity index, Tuni, enhanced to 99.87% at 1200 ml/hr.

ACS Style

Hesham I. Elqady; Ali Radwan; Abdallah Y.M. Ali; Mohammed Rabie; Essam M. Abo-Zahhad; Shinichi Ookawara; M.F. Elkady; A.H. El-Shazly. Concentrator photovoltaic thermal management using a new design of double-layer microchannel heat sink. Solar Energy 2021, 220, 552 -570.

AMA Style

Hesham I. Elqady, Ali Radwan, Abdallah Y.M. Ali, Mohammed Rabie, Essam M. Abo-Zahhad, Shinichi Ookawara, M.F. Elkady, A.H. El-Shazly. Concentrator photovoltaic thermal management using a new design of double-layer microchannel heat sink. Solar Energy. 2021; 220 ():552-570.

Chicago/Turabian Style

Hesham I. Elqady; Ali Radwan; Abdallah Y.M. Ali; Mohammed Rabie; Essam M. Abo-Zahhad; Shinichi Ookawara; M.F. Elkady; A.H. El-Shazly. 2021. "Concentrator photovoltaic thermal management using a new design of double-layer microchannel heat sink." Solar Energy 220, no. : 552-570.

Journal article
Published: 18 February 2021 in IEEE Access
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Flat plate solar collector (FPSC) is commonly used due to its low price, less complexity, and easier installation and operation. The low thermal efficiency is the main disadvantage of this type of solar collectors. In the present study, the thermal performance of the FPSC using alumina oxide -water and copper oxide -water nanofluids are evaluated. The effect of nanoparticle volume fraction and nanoparticle type are investigated theoretically and validated experimentally. A computational fluid dynamic model is developed. The model is validated with experimental result carried in this study. The model is simulated under the hot climate conditions of Egypt. The results showed that the presence of the nanoparticles in the working fluid of the FPSC increases the pressure drop in the collector, but thermal performance enhancement is also obtained. Further, an optimum nanoparticles volume fraction of 0.5% of copper oxide nanoparticle is found to attain the highest thermal efficiency of the collector. Furthermore, using copper oxide-water nanofluid is effective than using alumina oxide-water nanofluid at the same conditions.

ACS Style

A. A. Hawwash; Maqusood Ahamed; S. A. Nada; Ali Radwan; Ali K. Abdel-Rahman. Thermal Analysis of Flat Plate Solar Collector Using Different Nanofluids and Nanoparticles Percentages. IEEE Access 2021, 9, 52053 -52066.

AMA Style

A. A. Hawwash, Maqusood Ahamed, S. A. Nada, Ali Radwan, Ali K. Abdel-Rahman. Thermal Analysis of Flat Plate Solar Collector Using Different Nanofluids and Nanoparticles Percentages. IEEE Access. 2021; 9 (99):52053-52066.

Chicago/Turabian Style

A. A. Hawwash; Maqusood Ahamed; S. A. Nada; Ali Radwan; Ali K. Abdel-Rahman. 2021. "Thermal Analysis of Flat Plate Solar Collector Using Different Nanofluids and Nanoparticles Percentages." IEEE Access 9, no. 99: 52053-52066.

Research article
Published: 04 January 2021 in International Journal of Energy Research
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Finding the most optimal configuration of hybrid concentrator photovoltaic (CPV)‐thermoelectric power generator (TEG) system integrated with a microchannel heat sink (MCHS) is of great importance to achieve the best performance. Thus, two different hybrid configurations were chosen for the study including CPV/TEG/heat sink and CPV/heat sink/TEG. In addition, the performance of both hybrid configurations was compared with standalone CPV/heat sink and TEG/heat sink. In the conventional hybrid design, the TEG was directly attached to the back surface of the CPV module, whereas the other side of the TEG was integrated with MCHS. In the new hybrid design, the MCHS was sited between the CPV and the TEG module as both sides were subjected to concentrated solar radiation. Effects of varying the simulated solar concentration ratio, coolant flow rate on the solar cell temperature, and the total output power were experimentally determined. Results showed that the new design achieved a lower average solar cell temperature and a higher output power. At a solar radiation of 5000 W/m2, and a water flow rate of 80 g/min, the new design attained a solar cell temperature of 28°C with a conversion efficiency of 7.78% for the solar cell, and the total generated power was about 386 W/m2. In addition, the increase in the applied heat flux to the TEG unit to 10 000 W/m2 increased the total output power from 386 to 440 W/m2. Accordingly, the selection of an effective heat sink to absorb all the excess heat that emanated from the TEG side is of great importance to enhance the output electrical power generated by hybrid systems.

ACS Style

Ahmed Abdo; Takushi Saito; Shinichi Ookawara; Ali Radwan; Mahmoud Ahmed. Experimental study of the performance of concentrator photovoltaic/thermoelectric generator system integrated with a new 3D printed microchannel heat sink. International Journal of Energy Research 2021, 45, 7741 -7763.

AMA Style

Ahmed Abdo, Takushi Saito, Shinichi Ookawara, Ali Radwan, Mahmoud Ahmed. Experimental study of the performance of concentrator photovoltaic/thermoelectric generator system integrated with a new 3D printed microchannel heat sink. International Journal of Energy Research. 2021; 45 (5):7741-7763.

Chicago/Turabian Style

Ahmed Abdo; Takushi Saito; Shinichi Ookawara; Ali Radwan; Mahmoud Ahmed. 2021. "Experimental study of the performance of concentrator photovoltaic/thermoelectric generator system integrated with a new 3D printed microchannel heat sink." International Journal of Energy Research 45, no. 5: 7741-7763.

Paper
Published: 19 October 2020 in Sustainable Energy & Fuels
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Photovoltaic–thermal (PV/T) solar collectors convert solar radiation into electrical power and heat.

ACS Style

Ali Radwan; Takao Katsura; Saim Memon; Essam M. Abo-Zahhad; Osama M Abdelrehim; Ahmed A. Serageldin; Mohamed R. Elmarghany; Asmaa Khater; Katsunori Nagano. Development of a new vacuum-based photovoltaic/thermal collector, and its thermal and exergy analyses. Sustainable Energy & Fuels 2020, 4, 6251 -6273.

AMA Style

Ali Radwan, Takao Katsura, Saim Memon, Essam M. Abo-Zahhad, Osama M Abdelrehim, Ahmed A. Serageldin, Mohamed R. Elmarghany, Asmaa Khater, Katsunori Nagano. Development of a new vacuum-based photovoltaic/thermal collector, and its thermal and exergy analyses. Sustainable Energy & Fuels. 2020; 4 (12):6251-6273.

Chicago/Turabian Style

Ali Radwan; Takao Katsura; Saim Memon; Essam M. Abo-Zahhad; Osama M Abdelrehim; Ahmed A. Serageldin; Mohamed R. Elmarghany; Asmaa Khater; Katsunori Nagano. 2020. "Development of a new vacuum-based photovoltaic/thermal collector, and its thermal and exergy analyses." Sustainable Energy & Fuels 4, no. 12: 6251-6273.

Journal article
Published: 13 October 2020 in Applied Thermal Engineering
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The dense-packed high concentrator photovoltaic module (DP-HCPVM) is normally exposed to a very high heat flux concentrated from sunlight. The resultant high module operation temperature drops the overall performance and reduces the module life expectancy. Consequently, the provision of powerful cooling is compulsory for such structures. In this study, a complete three-dimensional (3D) model was developed to investigate the performance of a DP-HCPVM under the active cooling scheme to figure out its ability to attain effective heat dissipations. A new cooling convergent-divergent microchannel heat sink cases were numerically investigated and compared in terms of temperature distribution and electrical efficiency of a DP-HCPVM. The influence of heat sink design and inlet mass flowrate on the cooling performance of the heat sink device were examined. The same external dimensions are considered, and the flow was laminar with the inlet temperature of 25 °C for all designs for a reasonable comparison. The concept of variation flow direction by changing the inlet and outlet arrangement is adopted. The comparison between all studied designs was highlighted concerning surface average temperature, surface temperature uniformity, and pressure drop across the heat sink. The results indicated that the new convergent-divergent microchannel heat sink design achieved better effectiveness and heat transfer rate compared to the conventional straight microchannel heat sink design for DP-HCPVM thermal management, as it decreased the average cells temperature and temperature non-uniformity by 11.4% and 37.8%. Moreover, it was found that the electrical efficiency and Nusselt number were improved by 0.81% and 21.9% at the maximum studied inlet mass flowrate.

ACS Style

Abdallah Y.M. Ali; Essam M. Abo-Zahhad; Hesham I. Elqady; Mohammed Rabie; M.F. Elkady; Shinichi Ookawara; A.H. El-Shazly; Ali Radwan. Thermal analysis of high concentrator photovoltaic module using convergent-divergent microchannel heat sink design. Applied Thermal Engineering 2020, 183, 116201 .

AMA Style

Abdallah Y.M. Ali, Essam M. Abo-Zahhad, Hesham I. Elqady, Mohammed Rabie, M.F. Elkady, Shinichi Ookawara, A.H. El-Shazly, Ali Radwan. Thermal analysis of high concentrator photovoltaic module using convergent-divergent microchannel heat sink design. Applied Thermal Engineering. 2020; 183 ():116201.

Chicago/Turabian Style

Abdallah Y.M. Ali; Essam M. Abo-Zahhad; Hesham I. Elqady; Mohammed Rabie; M.F. Elkady; Shinichi Ookawara; A.H. El-Shazly; Ali Radwan. 2020. "Thermal analysis of high concentrator photovoltaic module using convergent-divergent microchannel heat sink design." Applied Thermal Engineering 183, no. : 116201.

Journal article
Published: 13 May 2020 in Energy Conversion and Management
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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.

ACS Style

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 Style

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.

Chicago/Turabian Style

Ali 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.

Journal article
Published: 09 April 2020 in Solar Energy
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The dense solar radiation received by a high concentration photovoltaic module (HCPVM) causes a high cell temperature. In this module, multiple solar cells were electrically connected in both series and parallel. The higher temperature of the solar cell in the series string limits the generated power for the whole string. Therefore, it is crucial to employ a uniform cooling mechanism for higher electrical performance along with a longer lifespan. The uniform cooling is required to attain safe operating temperature and prevent the hot spot formation. Hence, in the current work, a four-compartment microchannel heat sink is proposed for the thermal management of HCPVM under high solar concentration of 1000 suns (1 sun = 1000 W/m2). A three-dimensional (3D) conjugate heat transfer model with exergy analysis is developed and validated. This model was used to investigate the effect of inlet and outlet orientation of four quadrants microchannel heat sink as a cooling method for HCPVM. Eight different orientations of parallel-flow and counter-flow conditions were investigated and compared in terms of temperature non-uniformity, module power, and exergy performance. The results showed that the inlet and outlet orientation was a key role affecting the module temperature non-uniformity. For the counter-flow operated heat sinks, the HCPVM can be operated under a temperature non-uniformity of 3.1 °C at total inlet module mass flowrate of 350 g/min and solar concentration ratio of 1000 suns. In addition, the attained HCPVM electrical, thermal, and overall exergy efficiency were 37.2%, 8.2%, and 45.4% respectively at the same conditions.

ACS Style

Abdallah Y.M. Ali; Essam M. Abo-Zahhad; M.F. Elkady; Shinichi Ookawara; A.H. El-Shazly; Ali Radwan. Temperature uniformity enhancement of densely packed high concentrator photovoltaic module using four quadrants microchannel heat sink. Solar Energy 2020, 202, 446 -464.

AMA Style

Abdallah Y.M. Ali, Essam M. Abo-Zahhad, M.F. Elkady, Shinichi Ookawara, A.H. El-Shazly, Ali Radwan. Temperature uniformity enhancement of densely packed high concentrator photovoltaic module using four quadrants microchannel heat sink. Solar Energy. 2020; 202 ():446-464.

Chicago/Turabian Style

Abdallah Y.M. Ali; Essam M. Abo-Zahhad; M.F. Elkady; Shinichi Ookawara; A.H. El-Shazly; Ali Radwan. 2020. "Temperature uniformity enhancement of densely packed high concentrator photovoltaic module using four quadrants microchannel heat sink." Solar Energy 202, no. : 446-464.

Journal article
Published: 18 March 2020 in Energies
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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.

ACS Style

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 Style

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 (6):1418.

Chicago/Turabian Style

Ahmed 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.

Journal article
Published: 03 March 2020 in Fuel
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The main challenges of utilizing the Waste Cooking Oil (WCO) in diesel engines are that it released a large amount of NOx level, and it has a high viscosity, high pour point, and low volatility. Therefore, this study aims to scrutinize the impacts of adding gasoline as additives with WCO biodiesel on the combustion, emission, and exergy characteristics of a diesel engine run under various loads and a constant speed of 1500 rpm. The WCO biodiesel is produced employing the transesterification process with assisting of ultrasonic and mechanical dispersion devices, and it is characterized by applying GC–MS and FTIR analysis. The viscosity is diminished by approximately 5%, 11%, and 21% for BG2, BG4, and BG8, respectively. Three blending ratios of 2%, 4%, and 8% gasoline and 98%, 96%, and 92% WCO which are represented as BG2, BG4, and BG8, respectively. The results illustrate that the cylinder pressure and HRR are enlarged with the addition of gasoline with WCO. Fuel exergy rate and exergitic efficiency are heightened with adding gasoline. Engine emissions of CO, UHC, NOx, and smoke opacity are pointedly diminished by 25%, 30%, 20%, and 30% for WCO-gasoline blends compared to that of pure WCO. It can be deduced that the recommended mixing ratio of gasoline-WCO biodiesel blend is BG8 which achieved a considerable heightening in emission formations, principally NOx level and providing an acceptance value of fuel consumption.

ACS Style

M.S. Gad; Ahmed I. El-Seesy; Ali Radwan; Zhixia He. Enhancing the combustion and emission parameters of a diesel engine fueled by waste cooking oil biodiesel and gasoline additives. Fuel 2020, 269, 117466 .

AMA Style

M.S. Gad, Ahmed I. El-Seesy, Ali Radwan, Zhixia He. Enhancing the combustion and emission parameters of a diesel engine fueled by waste cooking oil biodiesel and gasoline additives. Fuel. 2020; 269 ():117466.

Chicago/Turabian Style

M.S. Gad; Ahmed I. El-Seesy; Ali Radwan; Zhixia He. 2020. "Enhancing the combustion and emission parameters of a diesel engine fueled by waste cooking oil biodiesel and gasoline additives." Fuel 269, no. : 117466.

Journal article
Published: 01 March 2020 in Solar Energy
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ACS Style

Takao Katsura; Saim Memon; Ali Radwan; Makoto Nakamura; Katsunori Nagano. Thermal performance analysis of a new structured-core translucent vacuum insulation panel in comparison to vacuum glazing: Experimental and theoretically validated analyses. Solar Energy 2020, 199, 326 -346.

AMA Style

Takao Katsura, Saim Memon, Ali Radwan, Makoto Nakamura, Katsunori Nagano. Thermal performance analysis of a new structured-core translucent vacuum insulation panel in comparison to vacuum glazing: Experimental and theoretically validated analyses. Solar Energy. 2020; 199 ():326-346.

Chicago/Turabian Style

Takao Katsura; Saim Memon; Ali Radwan; Makoto Nakamura; Katsunori Nagano. 2020. "Thermal performance analysis of a new structured-core translucent vacuum insulation panel in comparison to vacuum glazing: Experimental and theoretically validated analyses." Solar Energy 199, no. : 326-346.

Journal article
Published: 29 February 2020 in Solar Energy
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Thermal regulation of concentrator photovoltaic (CPV) systems is of great importance to keep silicon layer temperature within the maximum allowable temperature range, as it enhances overall performance and avoids potential solar cells damage. Therefore, a novel jet impingement mini- and- micro channel heat sink with a heat spreader integrated with a CPV system is designed. To evaluate the performance of the developed system, a three-dimensional conjugate thermo-fluid model for the solar cell layers, jet impingement with microchannel flow, and heat spreader is established. This model is numerically solved, and results are validated using the available measurements. The new system is then compared using several heat sink designs including a jet impingement-mini-channel with and without a heat spreader at different concentration ratios (CR) and coolant Reynolds numbers (Re). The findings indicate that at CR = 20, integrating a jet impingement-micro-channel heat sink, and a heat spreader with the CPV system accomplishes a uniform silicon layer temperature distribution with the lowest average temperature compared to other designs. In addition, the established design attains the highest net electrical power and electrical efficiency. The results of the current study demonstrate the effectiveness of combining active and passive cooling methods for thermal management of the CPV systems.

ACS Style

Mohamed Awad; Ali Radwan; O. Abdelrehim; Mohamed Emam; Ahmed N. Shmroukh; Mahmoud Ahmed. Performance evaluation of concentrator photovoltaic systems integrated with a new jet impingement-microchannel heat sink and heat spreader. Solar Energy 2020, 199, 852 -863.

AMA Style

Mohamed Awad, Ali Radwan, O. Abdelrehim, Mohamed Emam, Ahmed N. Shmroukh, Mahmoud Ahmed. Performance evaluation of concentrator photovoltaic systems integrated with a new jet impingement-microchannel heat sink and heat spreader. Solar Energy. 2020; 199 ():852-863.

Chicago/Turabian Style

Mohamed Awad; Ali Radwan; O. Abdelrehim; Mohamed Emam; Ahmed N. Shmroukh; Mahmoud Ahmed. 2020. "Performance evaluation of concentrator photovoltaic systems integrated with a new jet impingement-microchannel heat sink and heat spreader." Solar Energy 199, no. : 852-863.

Journal article
Published: 27 February 2020 in Applied Thermal Engineering
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High concentrator photovoltaic (HCPV) system are generally exposed to high solar concentration ratios and reach high temperatures. An advanced cooling technique is compulsory to attain the highest net output power along with the safe operation of the system components. Different designs of stepwise varying width microchannel heat sink are investigated in this study. The main purpose of this study is to investigate the influence of the channel geometry of longitudinal rectangular internal fins and different water inlet mass flow rates on the performance of an HCPV system. A three-dimensional thermal model is developed and used to compare the performance of four different designs of stepwise varying width microchannel heat sinks. These designs are compared with the conventional multichannel heat sink design. The results show that the heat sink design and the coolant mass flow rate have a significant impact on the cell temperature, electrical cell efficiency, system thermal efficiency, electrical exergy efficiency, thermal exergy efficiency, total exergy efficiency and thermal resistance of the heat sinks. For instance, using one of the proposed stepwise varying width microchannel heat sink at solar concentration ratio of 1000 suns and increasing the coolant flowrate from 25 to 1000 g/min decreased the solar cell temperature from around 71.7° C to 40° C with solar cell temperature non-uniformity decreased from 15.5 °C to 9 °C respectively.

ACS Style

Essam M. Abo-Zahhad; Shinichi Ookawara; Mohamed Esmail; A.H. El-Shazly; M.F. Elkady; Ali Radwan. Thermal management of high concentrator solar cell using new designs of stepwise varying width microchannel cooling scheme. Applied Thermal Engineering 2020, 172, 115124 .

AMA Style

Essam M. Abo-Zahhad, Shinichi Ookawara, Mohamed Esmail, A.H. El-Shazly, M.F. Elkady, Ali Radwan. Thermal management of high concentrator solar cell using new designs of stepwise varying width microchannel cooling scheme. Applied Thermal Engineering. 2020; 172 ():115124.

Chicago/Turabian Style

Essam M. Abo-Zahhad; Shinichi Ookawara; Mohamed Esmail; A.H. El-Shazly; M.F. Elkady; Ali Radwan. 2020. "Thermal management of high concentrator solar cell using new designs of stepwise varying width microchannel cooling scheme." Applied Thermal Engineering 172, no. : 115124.

Short communication
Published: 14 January 2020 in Case Studies in Thermal Engineering
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The semiconductor devices are widely employed for many applications. A significant amount of the heat must be dissipated properly to keep the devices' performance stable. Additionally, under high operation temperatures, a physical damage is possible due to thermal stresses that threaten the safety components and increase the failure rate. The development in the direction of more tightly packed electronic devices increases the challenges of offering an efficient cooling for these devices under high heat fluxes in a very restricted space. Hence, an advanced cooling technique is compulsory to attain the appropriate performance along with extending the lifespan of microelectronic devices. Stepwise varying width microchannel heat sink is considered one of the innovative cooling system from these microelectronic devices. In the current study, different designs of stepwise varying width microchannel heat sink were optimized, and their thermal performance was studied for more uniform cooling of microelectronics devices.

ACS Style

Essam M. Abo-Zahhad; Shinichi Ookawara; Ali Radwan; M.F. Elkady; A.H. El-Shazly. Optimization of stepwise varying width microchannel heat sink for high heat flux applications. Case Studies in Thermal Engineering 2020, 18, 100587 .

AMA Style

Essam M. Abo-Zahhad, Shinichi Ookawara, Ali Radwan, M.F. Elkady, A.H. El-Shazly. Optimization of stepwise varying width microchannel heat sink for high heat flux applications. Case Studies in Thermal Engineering. 2020; 18 ():100587.

Chicago/Turabian Style

Essam M. Abo-Zahhad; Shinichi Ookawara; Ali Radwan; M.F. Elkady; A.H. El-Shazly. 2020. "Optimization of stepwise varying width microchannel heat sink for high heat flux applications." Case Studies in Thermal Engineering 18, no. : 100587.

Journal article
Published: 05 December 2019 in Solar Energy
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Modifying the polycrystalline silicon solar cell by reducing the thermal resistance of the ethylene–vinyl acetate (EVA) layer is essential to enhance the thermal management process. This modification will improve the heat dissipation process from the silicon wafer especially at a higher solar concentration ratio (CR) and in return enhance the solar cell performance and output power. Thus, a modified design of a solar cell integrated with a microchannel heat sink is developed. In this new design, variations of the Ethylene-Vinyl Acetate (EVA) upper- and lower-layer thickness along with the interval width between the two consecutive silicon layers are investigated. To determine the effect of varying the design parameters on the cell temperature at various solar concentration ratios and coolant mass rates, a three-dimensional comprehensive model for the solar cell integrated with a heat sink is developed. The model is simulated and validated with numerical results and measurements. Results indicate that reducing the EVA lower layer thickness has a remarkable effect on the solar cell temperature. At a solar concentration ratio of 20, varying the EVA lower layer thickness from 1.0 mm to 0.2 mm results in decreasing the maximum cell temperature from 102.3 °C to 69.3 °C. With further increase of the concentration ratio up to 30, the maximum cell temperature reduces from 138.3 °C to 87.4 °C. It is found that at a coolant rate of 2000 gm/min, and a concentration ratio of 20, maximum temperature in the modified and conventional solar cell with a lower EVA thickness of 0.2 mm and 0.5 mm, reaches 69.3 °C and 81.5 °C, respectively. Furthermore, the conventional cell efficiency is about 8.90%, while the modified one achieves 9.6%. At a CR = 30, the maximum temperature of the modified cell is 87.4 °C, while it is beyond the permissible temperature for the conventional cell. However, the solar cell temperature was not affected by varying the EVA upper layer and the interval width between the silicon layers. The finding of the current results provides another direction for researchers to utilize a higher concentration ratio with polycrystalline silicon solar cells.

ACS Style

Abd El-Moneim A. Harb; Ali Radwan; Khairy Elsayed; Momtaz Sedrak; Mahmoud Ahmed. Influence of varying the Ethylene-Vinyl Acetate layer thicknesses on the performance of a polycrystalline silicon solar cell integrated with a microchannel heat sink. Solar Energy 2019, 195, 592 -609.

AMA Style

Abd El-Moneim A. Harb, Ali Radwan, Khairy Elsayed, Momtaz Sedrak, Mahmoud Ahmed. Influence of varying the Ethylene-Vinyl Acetate layer thicknesses on the performance of a polycrystalline silicon solar cell integrated with a microchannel heat sink. Solar Energy. 2019; 195 ():592-609.

Chicago/Turabian Style

Abd El-Moneim A. Harb; Ali Radwan; Khairy Elsayed; Momtaz Sedrak; Mahmoud Ahmed. 2019. "Influence of varying the Ethylene-Vinyl Acetate layer thicknesses on the performance of a polycrystalline silicon solar cell integrated with a microchannel heat sink." Solar Energy 195, no. : 592-609.

Journal article
Published: 01 November 2019 in Applied Energy
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ACS Style

Essam M. Abo-Zahhad; Shinichi Ookawara; Ali Radwan; A.H. El-Shazly; M.F. Elkady. Numerical analyses of hybrid jet impingement/microchannel cooling device for thermal management of high concentrator triple-junction solar cell. Applied Energy 2019, 253, 1 .

AMA Style

Essam M. Abo-Zahhad, Shinichi Ookawara, Ali Radwan, A.H. El-Shazly, M.F. Elkady. Numerical analyses of hybrid jet impingement/microchannel cooling device for thermal management of high concentrator triple-junction solar cell. Applied Energy. 2019; 253 ():1.

Chicago/Turabian Style

Essam M. Abo-Zahhad; Shinichi Ookawara; Ali Radwan; A.H. El-Shazly; M.F. Elkady. 2019. "Numerical analyses of hybrid jet impingement/microchannel cooling device for thermal management of high concentrator triple-junction solar cell." Applied Energy 253, no. : 1.

Journal article
Published: 23 October 2019 in Solar Energy
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The rate of heat gain or heat loss from the windows of existing buildings represents a large portion of building energy consumption in harsh hot or cold regions, respectively. Therefore, several thermal insulation technologies have been applied in new buildings. However, these technologies are difficult to implement in existing buildings. Therefore, this study proposes a new, low-cost insulation method using slim, transparent panels with structured cores, for the windows of existing buildings. To do this, five new distinct designs of vacuum insulation panels (VIPs) are proposed to retrofit insulation for the windows of existing buildings. The VIPs comprise a hollow-frame structured-core material encapsulated in a transparent multi-layered polymeric envelope. The effective thermal conductivity of VIPs with different spacers, namely, peek, modified peek, mesh, silica aerogel, and frame, are evaluated at different pressure levels. The spacers are 3D-printed and experimentally-examined. A 3D thermal model is developed and validated using the experimental results of the present work and results from the literature. First, the influences of spacer structure and vacuum pressure on the centre-of-panel thermal conductivity, light transparency, and VIP production costs are evaluated. Second, three different trial manufacturing methods for these VIPs are proposed and compared. Finally, the annual building heat gain and heat loss in two different harsh hot and cold regions, respectively, in Japan are estimated while applying these new proposed VIP designs to the existing windows. The results indicate that VIPs with frame and mesh spacers accomplish better insulation performance, with a centre-of-panel thermal conductivity of 7 × 10−3 W/m K at a pressure of 1 Pa. Further, the VIP with the peek spacer accomplishes the highest light transparency (0.88). Furthermore, using a frame-type VIP with a total thickness of 3 mm attached to an existing window as a curtain decreases the space heat loss by approximately 69.5%, whereas the light transparency decreases to 75%. In that regard, using a frame-type VIP attached to 3 mm-glass windows decreases window insulation costs by 72% compared with vacuum glazing thermal insulation.

ACS Style

Takao Katsura; Ali Radwan; Zhang Yang; Makoto Nakamura; Katsunori Nagano. Energy conservation using new structured-core and transparent vacuum insulation panels: Numerical simulation with experimental validation. Solar Energy 2019, 193, 885 -905.

AMA Style

Takao Katsura, Ali Radwan, Zhang Yang, Makoto Nakamura, Katsunori Nagano. Energy conservation using new structured-core and transparent vacuum insulation panels: Numerical simulation with experimental validation. Solar Energy. 2019; 193 ():885-905.

Chicago/Turabian Style

Takao Katsura; Ali Radwan; Zhang Yang; Makoto Nakamura; Katsunori Nagano. 2019. "Energy conservation using new structured-core and transparent vacuum insulation panels: Numerical simulation with experimental validation." Solar Energy 193, no. : 885-905.

Journal article
Published: 05 October 2019 in Applied Thermal Engineering
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Concentration of solar radiation onto the surface of triple-junction solar cells causes high cell temperature and system failure. Recently, several cooling methods were proposed for these systems. However, quantitative evaluation of the essential heat transfer coefficients to maintain stable operation of these systems at different meteorological and operating conditions is not found in the literature. Therefore, in this study, a comprehensive three-dimensional coupled thermal and structural model is proposed for the latest triple-junction AZUR SPACE solar cell. The model is used to investigate the performance of an HCPV system under different solar concentration ratios (CRs), ambient temperature, direct solar irradiance, wind speed, backside heat transfer coefficient, and copper-II substrate area ratios. In addition, a new structure of the solar cell is proposed by modifying the typical solar cell assembly by changing the area of the rear copper layer. The results indicate that by increasing the ambient temperature, CR and direct solar irradiance significantly increase the predicted cell temperature at the same backside heat transfer coefficient. In addition, increasing copper-II substrate area ratios significantly reduces the average cell temperature at the same backside heat transfer coefficient and CR. At the highest backside heat transfer coefficient, when the copper-II substrate area increased, the cell temperature decreased to a certain limit and subsequently remained constant. Critical values of the highest backside heat transfer coefficient were about 200, 600, 1000, and 1600 W/m2 K at CRs of 50, 500, 1000, and 1500 Suns, respectively. In addition, at the highest backside heat transfer coefficient of 1600 W/m2 K, the critical area ratio values were about 2, 3, 4, and 6 at CRs of 50, 500, 1000, and 1500 Suns, respectively.

ACS Style

Essam M. Abo-Zahhad; Shinichi Ookawara; Ali Radwan; A.H. El-Shazly; M.F. El-Kady; Mohamed F.C. Esmail. Performance, limits, and thermal stress analysis of high concentrator multijunction solar cell under passive cooling conditions. Applied Thermal Engineering 2019, 164, 114497 .

AMA Style

Essam M. Abo-Zahhad, Shinichi Ookawara, Ali Radwan, A.H. El-Shazly, M.F. El-Kady, Mohamed F.C. Esmail. Performance, limits, and thermal stress analysis of high concentrator multijunction solar cell under passive cooling conditions. Applied Thermal Engineering. 2019; 164 ():114497.

Chicago/Turabian Style

Essam M. Abo-Zahhad; Shinichi Ookawara; Ali Radwan; A.H. El-Shazly; M.F. El-Kady; Mohamed F.C. Esmail. 2019. "Performance, limits, and thermal stress analysis of high concentrator multijunction solar cell under passive cooling conditions." Applied Thermal Engineering 164, no. : 114497.

Conference paper
Published: 23 June 2019 in ASME 2019 17th International Conference on Nanochannels, Microchannels, and Minichannels
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In this study, a new design of double layer microchannel heat sink (DL-MCHS) has been monolithically fabricated using 3D metal printer and experimentally examined as a heat sink for concentrator photovoltaic (CPV) systems. Single phase liquid cooling using ethanol and flow boiling cooling using NOVEC-7000 coolant in the designed DL-MCHS are experimentally compared. The results proved that using the flow boiling cooling technique for the CPV systems attained a lower solar cell temperature with high temperature uniformity. In more details, flow boiling in counterflow (CF) operated DL-MCHS, attained a very low solar cell temperature close to the NOVEC-7000 boiling point with temperature uniformity of 0.2 °C over a wide range of coolant flow rate from 25–250 ml/hr.

ACS Style

Ali Radwan; Mohamed M. Awad; Shinichi Ookawara; Mahmoud Ahmed. Performance of Concentrator Photovoltaic Systems Integrated With Double Layer Microchannel Heat Sink. ASME 2019 17th International Conference on Nanochannels, Microchannels, and Minichannels 2019, 1 .

AMA Style

Ali Radwan, Mohamed M. Awad, Shinichi Ookawara, Mahmoud Ahmed. Performance of Concentrator Photovoltaic Systems Integrated With Double Layer Microchannel Heat Sink. ASME 2019 17th International Conference on Nanochannels, Microchannels, and Minichannels. 2019; ():1.

Chicago/Turabian Style

Ali Radwan; Mohamed M. Awad; Shinichi Ookawara; Mahmoud Ahmed. 2019. "Performance of Concentrator Photovoltaic Systems Integrated With Double Layer Microchannel Heat Sink." ASME 2019 17th International Conference on Nanochannels, Microchannels, and Minichannels , no. : 1.

Journal article
Published: 11 May 2019 in Applied Thermal Engineering
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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.

ACS Style

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 Style

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.

Chicago/Turabian Style

Ahmed 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.

Journal article
Published: 12 March 2019 in Applied Energy
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Sunlight concentration on photovoltaic cells causes a substantial increase in the cells’ temperature, which leads to a significant reduction in performance and irreversible decay of solar cells. Therefore, a novel cooling method based on two-phase flow boiling in monolithic double-layer microchannel heat sinks is developed to experimentally investigate the thermal regulation of concentrator photovoltaic systems. Two different designs of heat sinks, namely parallel and counter flow configurations, are integrated on the back-side of a photovoltaic module. Ethanol and Novec-7000 with standard boiling temperatures of 78.4 °C and 34 °C are examined as coolant fluids. The influences of varying the simulated solar light concentration ratio, coolant flowrate, coolant type, and heat sink design on the solar cell temperature distribution are experimentally investigated. The results indicate that two-phase flow boiling significantly reduces the maximum cell temperature, attains a uniform solar cell temperature distribution, and improves electrical efficiency. Furthermore, the microchannel heat sink flow arrangement affects the variation of solar cell temperature. Experimental results confirm that the parallel flow configuration attains effective cooling only at higher flowrates compared to the counter flow configuration. The findings of this study demonstrate the potential of two-phase flow boiling for the thermal management of concentrator photovoltaic systems.

ACS Style

Ali Radwan; Shinichi Ookawara; Mahmoud Ahmed. Thermal management of concentrator photovoltaic systems using two-phase flow boiling in double-layer microchannel heat sinks. Applied Energy 2019, 241, 404 -419.

AMA Style

Ali Radwan, Shinichi Ookawara, Mahmoud Ahmed. Thermal management of concentrator photovoltaic systems using two-phase flow boiling in double-layer microchannel heat sinks. Applied Energy. 2019; 241 ():404-419.

Chicago/Turabian Style

Ali Radwan; Shinichi Ookawara; Mahmoud Ahmed. 2019. "Thermal management of concentrator photovoltaic systems using two-phase flow boiling in double-layer microchannel heat sinks." Applied Energy 241, no. : 404-419.