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.