الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
The vast spread of air conditioners in the residential sector is one of the main reasons for this electricity shortage in Egypt in the last five years during the summer season. There are many energy efficient technologies have been used recently in cooling techniques. Solar cooling systems is one of these promising air conditioning techniques.
This study aims to provide decision support tools for selecting the best size of the main components of a small scale solar driven/assisted, silica gel-water, adsorption cooling system that is convenient for different climatic zones in Egypt based on the cost performance parameter for the use in residential homes.
To achieve the main objective of this work, a design optimization methodology has been developed. It builds on a computer dynamic simulation model has been carried out on the design variables, which are: the slope of the solar collectors, the solar collector area, the volume of the hot storage tank, the volume of the cold storage tank, and the thermostat set point of the auxiliary heating element. The dynamic simulation model was developed by Transient System Simulation program (TRNSYS) which is considered as a useful tool for simulating and evaluating the transient performance of thermal energy systems. Economic and environmental evaluations of the proposed systems have been performed as well. A validation of the model results was conducted with the experimental results of the solar driven silica gel-water adsorption cooling system at Assiut University Campus which has worked since 2012. The optimizationis based on a computer simulation for selecting the best size of the main components of a residential scale solar driven/assisted silica gel-water adsorption cooling systems with different solar fractions for four cities: Alexandria, Cairo, Assiut, and Aswan representing different climatic zones in Egypt. The experimental results show that under daily solar insolation of 21 to 27 MJ/m2, the daily solar collector efficiency during the period of system operation ranged from 50 % to 78 % with solar COP of the system which ranged from 0.13 to 0.3. The chiller average cooling capacity was varying from 3.5 to 6.6 kW and daily COP between 0.43 and 0.63 under different operating conditions. The chiller performance can be enhanced by decreasing the temperature of the cooling water and by using city water of temperature about 27.7 ˚C as a cooling medium instead of the cooling tower enhanced the chiller COP by 40 % and the chilling power by 17 %. The proposed portion of a residential building assumed to be cooled by the solar assisted cooling system is from the standard home in new societies across Egypt. However, as the small-scale solar driven chiller of 8 kW cooling capacity is used in this study a part of the first floor with a surface area of 36 m2, is to be the conditioned space that can be met by this small-scale solar assisted adsorption cooling system optimised in this study. The performance of the optimized systems for the investigated locations is not much different: the efficiency of the solar collectors was ranged from 0.52 and 0.58, and the COP of the chiller was varied from 0.41 to 0.46. The optimal area of the solar collectors is 1.25 m2/kWc for Alexandria and 1.5 m2/kWc for Cairo, while for both Assiut and Aswan the optimal area is three m2/kWc. The optimal volume of the hot water storage tank is almost the same for the four cities, and it is about 0.1 m3/kWc where there is no excess solar energy to be stored; it just works as a buffer for all the investigated cities. The optimal volume of the cold water storage tank was 0.23 m3/kWc and 0.2 m3/kWc for Alexandria and Cairo, and it was 0.13 m3/kWc, and 0.16 m3/kWc for Assiut and Aswan, respectively. For the entire cooling season, the system can be able to meet the entire daily cooling demand for about 73.9 % of the cooling season days for Alexandria. For Cairo, the optimal cooling system can be able to meet the 36 m2 floor area daily cooling demand for about 85.6 % of the cooling season days. The optimal proposed solar cooling system can meet the 36 m2 floor area daily cooling demand for 91.5 % and 71.9 % for Assiut and Aswan, respectively. For all locations under investigation, the adsorption chiller can produce more than 7 kW as cooling capacity with about 0.42 COP. The initial cost of the optimal residential solar assisted silica gel-water adsorption cooling system for Egypt ranged from 3603 to 3909 €/kWc to cool a 36 m2 floor area according to the climatic zones of Egypt under investigation. The contribution of the solar collecting system accounts for 7 % to 13 % of the total system initial cost. The chiller and cooling tower have the highest contribution, and it ranges from 38 % to 41 %. The cold storage tank and the fan coil units share in 5 % to 6 % of the initial cost. While the contribution of the auxiliary heating element is from about 7 % to 8%, and the pumps contribute with 8 % to 9 %. The installation and other system components share in 29 % of the initial system cost. from these results, the proposed small-scale solar thermal adsorption cooling system is more suitable for the climatic zones represented by Cairo and Assiut which are Cairo and Delta, Northern Upper Egypt, and Southern Upper Egypt zones. The running cost of the optimal system for Egypt ranges from 53 to 70 €/kWc with Correspondance CO2 emissions ranged from 588 to 764 kg of CO2eq./kWc. Although the high installation cost of the proposed solar-assisted residential size adsorption cooling system, the system could meet the cooling load of only 36 m2 of the total floor space of a residential home. This makes the solar thermal cooling systems cannot compete with another market available solar driven or conventional cooling systems for residential sector application.