Top-down Plantwide Control of a Parallel Double Effect Aqueous Lithium Bromide Absorption Chiller

Kris Prasopasanti and Paisan Kittisupakorn
Process Engineering Research Unit, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
Abstract—An alternative control structure for a parallel double effect aqueous lithium bromide absorption chiller has been designed using top-down plantwide control structure analysis. Concept of self-optimizing control and location of throughput manipulator (TPM) have been utilized to improve performance of the control system economically. As the results, while a combination of liquid flowrate out of each generator is used as a self-optimizing measurement to control a spiting ratio, coefficient of performance (COP) can be increased up to 0.5% while heat source is supplied less than nominal value. In addition, by changing the position of TPM from chilled water flowrate to heat source flowrate, crystallization condition can be prevented more effectively, resulted in less back-off required and higher plant capacity by approximately 2.39%.

Index Terms—Absorption chiller, Plantwide control, Control structure design

Cite: Kris Prasopasanti and Paisan Kittisupakorn, "Top-down Plantwide Control of a Parallel Double Effect Aqueous Lithium Bromide Absorption Chiller," International Journal of Mechanical Engineering and Robotics Research, Vol. 8, No. 2, pp. 260-264, March 2019. DOI: 10.18178/ijmerr.8.2.260-264
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