A Thermodynamic Study on Residential Ammonia Water Absorption Cooling Technology

• Main Authors: Wani JamaalMorgan, 摩根
• Other Authors: Wei-Hsiang Lai
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/hu94gt

碩士 === 國立成功大學 === 能源工程國際碩士學位學程 === 107 === Humankind currently faces a global challenge in the form of global warming. The root cause of global warming has been attributed to excess atmospheric CO2 caused by burning fossil fuels for energy. To alleviate the impacts of global warming, the demand on fossil fuels must be reduced. Conventional vapor compression refrigeration is an energy demanding process which accounts for up to 20% of the global energy demand. A more carbon neutral alternative to vapor compression is that of absorption refrigeration. Absorption refrigeration is a promising alternative capable of utilizing low grade solar energy for cooling. This paper first uses the first law of thermodynamics to model the steady state performance of this system using the numerical modelling software Engineering Equation Solver (EES). Subsequent to modelling the system was optimized using a conjugate method algorithm. The aim of the optimization was to identify the optimal parameter combination that promotes the highest Coefficient of Performance. Via optimization, the Coefficient of performance of the has been shown to increase by 7.8% when compared to the base line model proposed by Aman et al[20]. In this study a One-at-A-Time sensitivity analysis was also carried out to investigate how each input parameter impacts the optimal performance of the system. It was shown that COP increases with increasing absorber temperature, evaporator temperature and heat exchanger efficiency. Conversely, COP decreases with increasing condenser temperature. The generator temperature uniquely increases the COP until a certain plateau point, subsequent to the plateau point COP decreases with further increase in generator temperature. This study also explores the potential of combining an ejector with the traditional ammonia water absorption model. The ejector proved to be a promising addition to the ARS as it increased the systems COP from 0.65 to 1.33. Furthermore, it was showed that the ejector is uniquely suitable for residential cooling where evaporator temperatures of 16-24oC are required.