Design and Analysis of a Solar Assisted Absorption Cooling System Integrated with Latent Heat Storage

Air conditioning is one of the major consumers of electrical energy in many parts of the world. The demand can be expected to increase because of the changing working times, increased comfort expectations and global warming. With more air conditioning units, the electricity demand has been rising thereby increasing the use of fossil fuels and nuclear energy. A drastic change, therefore, should be implemented in the energy structure of the developed countries. Environmentally friendly and energy efficient technologies should be introduced in which the environmental impact of the conventional air conditioning system is minimized. Solar radiation as a sustainable energy resource is one of the most available forms of energy on the earth surface which could reduce the fossil fuel consumption and CO2 emission to the atmosphere. Solar cooling is a possible technological alternative to conventional air conditioning systems that has recently attracted a growing interest. A solar assisted absorption cooling system as a sustainable solution for cooling systems could provide both heating and cooling of a building. Since the solar energy is available for only a fraction of the day and its availability depends on several factors such as latitude and sky clearness, the storage of it is an important concern. Thermal energy storage is a practical way in conserving the solar energy as it can reduce the discrepancy between the energy supply and demand. Latent heat storage units (LHSU) using Phase Change Materials (PCMs) are promising candidates as heat storage media. In this thesis, the behavior of a solar assisted single effect absorption system integrated with LHSU was investigated. The mathematical model for the single effect absorption system and the LHSU based on the mass and energy balances and heat transfer equations were developed. The models were implemented in MATLAB and the numerical results were validated with the experimental results from the literature. Based on the cooling demand of a specific building (waiting room in Schiphol airport) the absorption system and the LHSU were designed and the behavior of each system for different control parameters is investigated. For the designed single effect absorption system, variation of the COP and the evaporator heat transfer rate at the different flow rates and temperatures of the external cool water, hot water and the chilled water were studied. The results show that the chilled, hot and cooled water temperatures have significant effect on the performance of the absorption system. For the designed latent heat storage, several numerical investigations were conducted. The impact of the key parameters e.g. the mass of PCM, the number of tubes inside the PCM container and the radius of the tubes, on the thermal performances of the latent heat storage and the melting time duration were studied. The behavior of the designed latent heat storage unit in charging process with varying solar collector field area was studied subsequently. The discharging process of LHSU for the maximum cooling demand of the building was investigated. It was observed that the designed LHSU could provide the requested hot water temperature for more than 10 hours which is sufficient for driving the air conditioning system.Sustainable Process and Energy TechnologyProcess and EnergyMechanical, Maritime and Materials Engineerin