| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 106 === The purpose of this study is to set up an analysis system for air conditioning systems. The first part of the system was construct based on physics. For this purpose; the temperature of refrigerant, temperature and flow rate of water, and input power of compressor have been measured for calculating the coefficient of efficiency(COP), pump efficiency, and irreversibility. Another aim was to develop a method for predicting the performance of chiller. The models for predicting the outlet temperature, input power of compressor, and COP were constructed based on a large dataset obtained from the experiments. The multiple regressions were compared with long short-term memory(LSTM) based recurrent neural network(RNN) for the prediction error. The objective for the analysis system is to make diagnosis and long term monitoring for air conditioning systems simpler and feasible in the industry.
The experiments were conducted including water cooled chiller and packaged air conditioner which are located at the industrial area of the collaborate company Dragon Steel Co.,Ltd., which is subsidiary of China Steel Co.,Ltd.. To verify the reliability and validity of the two main idea of the study, the examination processes were carried out with these two cases.
The results indicate that the analysis system for detecting the performance of chiller and heat pump is practicable. The trend of the COP, pump efficiency, and irreversibility simulated from the analysis system are fit to the theory and the references. On the other hand, the study shows that the LSTM neural network provides the best results due to the strong ability to model the temporal relationship between time series. For each output parameters, LSTM structure performs more accurate and stable than multiple regression. The analysis system only needs to measure the temperature of refrigerant and water which is more easily than pressure drop and flow rate to obtain. The analysis system could be proposed as an alternative method for engineers to diagnosis or monitor air conditioning systems.
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