Simulation of solar cooling system

• Main Author: Goh, Dennis Kim Lai.
• Other Authors: Tan Fock Lai
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Mechanical engineering::Alternative, renewable energy sources; DRNTU::Engineering::Mechanical engineering::Power resources
• Online Access: http://hdl.handle.net/10356/39568
• Institution: Nanyang Technological University

As our climate becomes hotter due to global warming, and the demands for air conditioning rises, it is important use an alternative solution to meet our demands and at the same time to reduce the amount of fossil fuel consumption and harmful emissions to the environment. Using solar energy can be a solution to that demand, as solar radiation is an abundant source of clean energy which goes to waste every day. Combined with the use of absorption chillers, there are many advantages to using solar powered air conditioning. The main objective of this study is to develop a computational model that would simulate a solar absorption cooling system. This model will be created using the simulation program, TRNSYS, while considering three main specific areas of work. First is to implement the computational model for the absorption refrigerant system. Second is to optimize sizing of system components to suit the subtropical climate of Singapore. Thirdly, to compare the difference of the system performance while using evacuated tube collectors instead of flat plate collectors. The results of the optimization process of the solar absorption refrigeration system consists of a 3.5kW absorption chiller, with a working COP of 0.67, a 35m2 evacuated tube collector inclined at 25o from the horizontal, and a 800-l thermal storage tank with auxiliary heating set to 84oC. While running on a 24-hour basis, the system works on a negative solar fraction; meaning that the amount of auxiliary heating requires is greater than the amount of useful heat gained by the solar collector. Fortunately, the system runs on positive solar fraction when it is set to operate during peak load periods only. From the simulation, the system is shown to run on positive solar fraction for 21.1% of the entire duration of the year. In addition, the amount of energy consumption is significantly reduced as electrical power is only used to supply auxiliary heating, operate the absorption chiller and pumps, compared to a conventional air conditioning system.