# Modelling And Control Of An Air Conditioning System With An Emphasis On Cooling Coil Behaviour

PhD Thesis

Deng, Shi-Ming (1991). Modelling And Control Of An Air Conditioning System With An Emphasis On Cooling Coil Behaviour. PhD Thesis Council for National Academic Awards Institute of Environmental Engineering, South Bank Polytechnic https://doi.org/10.18744/lsbu.95vq5
Authors Deng, Shi-Ming PhD Thesis A review of the literature on the control of air conditioning systems has been undertaken. It shows that the behaviour of sensors and the relationship between measurements and bulk conditions cause significant difficulties. A simple air cooling and dehumidifying experimental plant and a non-linear thermodynamic mathematical model have been simultaneously developed to investigate the control of air coolers with an emphasis on the cooling and dehumidifying process. The radio frequency interference encountered in using the frequency inverter for varying the compressor speed presented major problems. It was suppressed by using shielding, filtering and common grounding techniques with high accuracy. The equations describing the behaviour of the DxX evaporator in the model are unique. The mathematical model has been validated and simplified using classical control theory. Transfer functions derived during the validation processes were simple mathematical models and are separately applicable. The techniques employed are shown to be effective methods for model validation. Two types of intelligent controller have been derived. For situations where the bulk air conditions can be measured, a closed loop intelligent controller with a combination of simple PID control algorithms’ and linguistic rules has been developed. For situations in which the air bulk state is difficult to measure, an open loop intelligent controller was derived. It combined some key parameter measurements in the cooling system and a few mathematical statements with some linguistic rules. Experiments on the controllers showed that both control accuracy and stability were achieved. Two new control concepts for variable speed compressor systems were investigated with the validated mathematical model. Promising results from the model simulation showed that research and development would be worthwhile. 1991 London South Bank University https://doi.org/10.18744/lsbu.95vq5 1991_PhD_Deng.pdfLicenseCC BY 4.0File Access LevelOpen 1991 30 Nov 2023

https://openresearch.lsbu.ac.uk/item/95vq5

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 1991_PhD_Deng.pdf License: CC BY 4.0 File access level: Open

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