Renewable energy applications play a major role in covering the energy demand for building cooling and ventilation. In this paper, an experimental investigation is performed on cooling and ventilation of a building room locating in New Borge Alarb city, Alexandria, Egypt by new combination of solar chimney and geothermal air tube heat exchanger system. PV panel is installed by new technique at the chimney back to produce power and its performance is compared to an identical PV outside the room. The study is performed for the chimney and PVs facing south of an angle with the horizontal 30° and 45° and for natural and forced airflow inside the geothermal tube. The geothermal tube and chimney ventilation systems are compared with the natural ventilation system of the solar chimney and window. The results indicate that the proposed systems prove their ability to cool the room temperature up to 3.5 °C and change daily its air 42 times. Minimum ventilated air occurs at natural geothermal tube-chimney system of angle 30°. The ratio of the total daily ventilated air by natural geothermal tube-chimney to that by chimney-window is about 56.3% and 65% at 30° and 45°, respectively and for heat released is 55.6% and 64%, respectively. Maximum daily heat released from the room is achieved at chimney inclination angle 45° for natural geothermal tube-chimney-PV system. Maximum PV output power inside the chimney represents 70% of the maximum PV output power outside the chimney which is 120 W/m2 at chimney inclination angle 30°.
In this study, the performance of single slope solar still combined with enhanced condenser and integrated with parabolic trough solar collector (PTC), is assessed based on productivity, energy, exergy, exergoeconomic, and enviroeconomic methodologies. Experiments are conducted using various saline water media inside a basin exposed to the hot weather conditions of Sohag city in Upper Egypt. Several solar still configurations are tested: conventional solar still (CSS), modified solar still (MSS) using aluminum heat sink as enhanced condenser (HSC), modified solar still incorporated with PTC (MSS + PTC), modified solar still comprising sand as a porous media inside the basin (MSS + SD), and modified solar still comprising sand inside the basin and incorporated with PTC (MSS + SD + PTC). The experimental findings revealed that the MSS + SD + PTC achieved the highest freshwater productivity of 4.65 L/m2 in winter and 9.75 L/m2 in summer, leading to an improvement of around 113 % in winter and 146 % in summer compared with the CSS system. The highest increase in energy and exergy output per year is obtained in the case of MSS + SD + PTC at 139 % and 245 %, respectively. Incorporation of PTC into the MSS system for all studied water media is found promising in terms of energy payback time, cost, and freshwater yield compared with MSS without PTC. The exergoeconomic and environmental parameters of the active systems are found more effective compared with those of the passive systems.
This study aimed to develop a new approach to build a functioning groundwater monitoring system by detecting a reduced set of observation wells (OWs) that optimally matches the hydraulic heads measured by other OWs within the field, namely as leader wells (LWs). The optimization models used in this work are the well-known genetic algorithm (GA), modfied genetic algorithm (MGA) and a new progressive combination (PC) model. Optimization was applied to achieve three sequential selection processes: best input combinations (BICk), LWs and core leader wells (CLWs) selection. This approach was applied to the Assiut New Barrage (ANB), a megaproject located in Assiut city, Egypt. The results show that nine LWs among 33 OWs are adequate for regular monitoring, with a reduction ratio of 72.72%. Moreover, assigning CLWs among LWs increases the accuracy of fitting to existing OWs, and helps to understand the spatial relationships between OWs.
This paper presents series of experimental studies on newly developed basalt fiber reinforced polymer (FRP) grids for the flexural strengthening of reinforced concrete beams. The study includes tensile behavior of the basalt FRP grids with three types of thickness, bonding behavior between the basalt FRP grids and the concrete with epoxy resin, and flexural behavior of the reinforced concrete beams strengthened with basalt FRP grids. The results revealed that the modulus of elasticity of the basalt FRP grids ranged between 40 and 43 GPa, and their tensile strength ranged between 815 and 931 MPa. The bond stress–slip behavior of the basalt FRP grids and concrete exhibited a ductile failure manner in comparison to that of FRP sheets and concrete; the bond strength of the tested basalt FRP grids was in the range of 3.26–6.06 MPa, and its slip at peak ranged between 0.15 and 0.4 mm. Beams strengthened with basalt FRP grids failed by crushing of compressive concrete or fiber reinforced polymer rupture and no debonding failure was observed for any of the tested beams.
Reinforced concrete shear walls are the most common lateral-force-resisting system in reinforced concrete structures. Recent experimental studies have proven the applicability of using glass fiber-reinforced polymer (GFRP) reinforcement in lateral-resisting concrete structural systems (shear walls and columns). In this study, five concrete shear walls reinforced with GFRP bars and spirals were tested under reversed cyclic quasi-static loading and constant axial load. The main difference between the walls was the GFRP reinforcement configuration in the boundary elements. Two shear walls included boundaries reinforced with square GFRP spirals, while the third shear wall had boundaries reinforced with circular GFRP spirals. The remaining two shear walls had higher confinement of boundary elements consisting of square GFRP spiral embedded inside rectangular GFRP spiral in one and rectangular GFRP spiral with two GFRP ties in the other. The main objectives were to assess the impact of increasing the confinement level in the boundaries and the effect on inelastic deformation capacity. The walls with higher confinement clearly achieved higher drift ratios and strength. The envelope curves were bilinearly idealized. The elastic-plastic transition point and the maximum deformation limit were identified based on the seismic performance of the test specimens. The recorded inelastic rotation capacity of the test walls achieved the required level for lateral-resisting systems. Moreover, the ductility-based force modification factor was assessed and a new value of 2.4 was suggested for implementation in FRP design codes.
Glass fiber-reinforced-polymer (GFRP) bars are increasingly recognized as being suitable as the primary reinforcement in concrete structures. In recent years, many researchers have been studying their seismic performance as a lateral resisting system. Because of the lack of experimental data, GFRP bars are still not recommended for seismic design. Given the need for comprehensive seismic-performance assessment, hysteretic models must be developed depending on GFRP bar properties. The primary purpose of this study was to identify the various parameters controlling the hysteretic response of GFRP-reinforced shear walls. Six fullscale specimens reinforced entirely with GFRP bars were recently constructed and tested under the combined action of reversed cyclic lateral load and constant axial load. The test results show stable performance and an acceptable level of deformability. An analytical model was developed using the experimental results for correlation, aiming to reproduce the hysteretic response. The model was achieved by investigating the parameters that control the hysteretic response and studying their effect on the deterioration rate. The cumulative dissipated energy, the cyclic distortion due to stiffness degradation, and the idealized load-displacement curve were analyzed. The proposed model was compared with the experimentally generated response and simulated the hysteretic response of GFRP-reinforced shear walls with acceptable accuracy.
