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Amongst the membrane distillation techniques, the air gap configurations showed an outstanding thermal efficiency, while a decline in productivity was recorded due to the additional thermal and mass resistances. The current study proposes minimizing the additional thermal and mass resistances by altering the condensation process to dropwise condensation. Depositing a layer of reduced graphene oxide using the electrophoretic deposition technique on the copper condensation plate was investigated to obtain a hydrophobic nature and attain dropwise condensation. Moreover, different operating conditions were examined for the optimum conditions, which were 45 V, 30 s, 1 cm, and 0.5 mg/ml, for the applied voltage, deposition time, distance between electrodes, and concentration, respectively. This modified condensation plate was investigated experimentally on the lab-scale test rig and showed an improvement in the productivity of 12.5% and 28.5% at the minimum and maximum feed temperatures, respectively. On the other hand, solar energy was utilized to eliminate the heating source required for the membrane distillation unit. A high concentration photovoltaic (HCPV) unit was introduced numerically in the current work with 36 multijunction cells. Furthermore, a microchannel heat sink was successfully designed to keep the cells from thermal degradation. The numerical results showed that the HCPV system could supply hot water up to 55 °C and produce electric power up to 230 W.

Pure water shortage is a crucial issue that needs very rapid, applicable, and economical solutions. Membrane distillation is a promising technique, primarily when supplied with a sustainable heating source. The current work introduces the hybridization of high concentrating photovoltaic (HCPV) with membrane distillation (MD) to gain the maximum benefits from available solar energy. The challenge regarding the HCPV unit is to incorporate an efficient cooling system that could maintain the cells within the manufacturer’s recommended range. On the other hand, the challenge regarding the MD unit is the high energy required for water heating. The current work introduces an effective microchannel cooling system that could maintain the cells within the safe range and utilize this removed thermal load to be the heating source for the MD unit. The HCPV has been solved numerically using Ansys 2020 software, while the MD unit has been investigated numerically and experimentally. It was found that to keep the maximum cell temperature within a safe range, the coolant flow rate should be at least 370 ml/min, with a corresponding coolant outlet temperature of 68 ºC. Moreover, the MD distillation unit has been proved experimentally to produce approximately 46 kg/m2per day. Electric power of about 685 W is available with the system.

Concentrating photovoltaic technology is growing rapidly among other solar energy technologies, as it reaches an electrical conversion efficiency up to 46%. The solar cell temperature increases during the conversion process, which in turn negatively affects the system’s performance by decreasing its efficiency. Thus, for safe and efficient operation, low and uniform temperature should be achieved. In this work, numerical simulations were completed to study and compare two microchannel heat sink designs as cooling devices for a high concentration photovoltaic (HCPV) system. ANSYS Fluent software was employed to solve three-dimensional conjugate heat transfer equations. The comparison was conducted under uniform solar radiation with a concentration ratio of 1000 suns (1 sun = 1000 W/m2) and a wide range of coolant inlet flowrate. The impact of heat sink design and coolant inlet flowrate variation were studied and highlighted regarding average cell temperature, electrical efficiency, temperature non-uniformity, and local temperature distribution. The results showed that heat sink design has a remarkable impact on the cooling performance of the HCPV/Thermal system. Whereas, configuration 1 achieved a lower average cell temperature by 11% than configuration 2, while the electrical efficiency was increased by 1.4%, at the minimum studied flowrate.

This work investigates the incorporation of a flat plate solar collector into an air gap membrane distillation (AGMD) system to produce pure water from water wells in Egypt. First, it considers the metrological data for Borg El Arab city, which is located at the north of the western desert in Egypt. A three-dimensional AGMD numerical model is established and solved using ANSYS 2019 commercial software, after setting suitable boundary conditions. Once the pure water flux is predicted at certain feed water inlet and outlet temperatures, a thermal analysis of the flat plate solar collector is introduced to estimate the required solar collector area to produce the required pure water flux.

Thermal management is extremely required for concentrator photovoltaic (CPV) to prevent any thermal stress or physical damage. Yet, offering an adequate, reliable, and practical thermal management system for CPV is still challenging. In this work, the double-layer microchannel heat sink (DL-MCHS) is investigated for CPV cooling. To achieve this objective, a three-dimensional (3D) conjugate heat transfer model for the fluid flow in the DL-MCHS coupled with the thermal model for the solar cell, is done. The assessment of considering the inlet and outlet headers in the computational fluid mechanics (CFD) simulations are highlighted. The results reveal that including headers in the numerical study leads to predicting the accurate thermo-hydraulic performance of the DL-MCHS, especially in the CF. However, slight predicted variations have been obtained when PF operated. Moreover, neglecting the header in the CFD calculations significantly affect the calculated pumping power for both PF and CF operated. The potential of this intensive study demonstrates that there is an obvious difference in the CFD simulation figures when the DL-MCHS attached by headers in the CFD calculations.

This manuscript investigates an opportunity of improving the dye elimination from wastewater by non-thermal plasma. Computer simulation technology (CST) was utilized for the double pin-to-plate configuration in 3D software simulation package for prediction field and voltage among the high voltage and the ground electrodes. The outcomes indicated that optimal gap separation for non-thermal plasma is about 5 mm. This optimal distance was used for corona region and ozone production. Experimental arrangement of double pin-to-plate discharge method has been deliberate examined the elimination of Acid Blue 80 dye. The influence of contact time, initial concentration, solution pH and gap distance have been established on Acid blue removal efficiency. The color removal performance using corona discharge displayed 80% dye color elimination competence within 10 min. The whole color removal was attained after 35 min for diverse concentrations from 5–100 ppm. In addition, the corona current performance at different initial solution pH was presented. Furthermore, the discharge energy and corona current were measured at different gap distances. Energy yield and electrical energy per order (EE/O) for decolorization in diverse gap distance were considered.