Design and Optimization of Solar Thermal Vapor Absorption Refrigeration System Integrated With Phase Change Material for Cold Room Application
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Date
2023-06
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Addis Ababa University
Abstract
Now a day many cooling systems are used in order to keep the food product in the conditioned room. For this cooling effect, mostly conventional compression refrigeration system is applicable which has high-energy consumption and the working fluid of it that is HFCC causes the environmental degradation and ozone layer depilation. Using renewable energy is a promise-able technology to solve the above problem but its energy source is not pretty much. For energy of low quality source absorption-based cooling system is compatible what if it requires energy storage system. This thesis emphasizes optimizing the vapor absorption refrigeration system of performance 7.772 kW. Material that undergoes phase change (PCM) is combined utilizing solar thermal energy to provide cooling capacity, allowing the system to function at night as a backup thermal energy storage system. The cooling load was calculated for 6500 kg of fish is to be stored in 4x2x2.5 m size of the room. By using ASPEN plus software, the vapor absorption refrigeration for this load was optimized and modeled. Ammonia, which is created by distilling an ammonia-water (NH3-H2O) solution in the generator, serves as the refrigerant for the VAR system. The obtained Coefficient of Performance was 0.7, this is a typical performance for a vapor-absorbing system. The power source of VAR system was solar based heat energy where solar radiation is under Hawassa weather conditions. This solar thermal heat energy supplied for 6 hours for VAR system and the remaining 18hrs is provided by PCM storage system. The size of the CPC collector was 28.26 m2. Additionally, the system's performance is examined in MATLAB integrating with ASPEN plus software. The charging and discharging temperature variation with respect to time for thermal storage is 3.5 and 9.5 hours for minimum solar radiation and 1.5 and 15.5 hours for maximum solar radiation respectively
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Keywords
COP, Cooling load, solar thermal, cold room, PCM, optimization, ASPEN plus, MATLAB, absorption