الفهرس 
CHAPTER I: INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Renewable energy sources have become an interesting topic for researchers and scientists. They are under focus to eventually replace traditional resources of energy. Geothermal energy for heating and cooling in various applications, such as greenhouses, fish farms, animal farms, district air heating systems, is used as a renewable energy source instead of traditional air conditioning systems that depend on refrigerants. It additionally saves the electricity generated from burning fossil fuel. On the other hand, a solar chimney is considered, according to many previous studies, as an efficient way to perform natural ventilation by circulating the air in a target application to support cooling a medium. Combining both geothermal energy and a solar chimney in one application to provide air conditioning with high performance is the base of this study. The study contains the design of a complete system, including the effect of governing parameters such as the air-conditioned volume, the number of suction ducts, the suction duct length, the suction duct diameter, the level of the suction ducts, the height of the solar chimney and the time required to reach the desired temperature. The present work adopts a numerical approach to determine governing parameters and relate them through a steady-state computational fluid dynamic (CFD) simulation to provide the fluid velocity and temperature at all the system locations. The present work applies the commercial solver ANSYS FLUENT 16 as CFD. Different meshes are generated in this analysis for the fluid. The study introduces an analysis of a hybrid closed loop geothermal-solar energy system to control the air temperature. This hybrid system can manage the temperature in different air-conditioning applications, such as greenhouses, living quarters, and buildings. An experimental study in Damanhur city, Beheira Governorate, Egypt is carried out to provide air conditioning for a room of L 2m x W 2m x H 2m by 5 meters using a geothermal PVC air pipe of 2 inches in diameter, 5.3 mm in thickness and buried at 2 m depth, supported by a solar chimney to provide a natural driving force for the air inside the closed-loop system, and a driving fan for use when the isolation of the solar chimney is required at night or to avoid unnecessary increase of temperature. Both a CFD Ansys 16 and an Open Foam are used as an open-source program for studying 9 closed-loop geothermal air pipe system cases, for both the summer and winter at different pipe diameters; 0.17, 0.35 & 0.65 meters, and different pipe total lengths 47, 64 & 87 meters, for an air conditioned room of L 3m x W 3m x H 3m combined with a 1m length solar chimney at a 45ᵒ angle. Results show the efficiency of a closed-loop system for heating and cooling using a combination of geothermal and solar chimneys. The validation of the numerical model was carried out using experimental results. The CFD system provides the highest air conditioning temperature difference close to 5 ᵒC at 0.65 m diameter and 87 m total length case and the lowest difference of 1 ᵒC at 0.17 m diameter and 47 m total length case, indicating the effect and relation between pipe diameter, pipe length, air temperature, airflow rate and time. During winter conditions the maximum temperature difference that can be achieved with the proposed design is 4.8 while in summer conditions it is 5.7. The findings of the generated formula are reasonably close to those of the experiment results.