Optimal Control of District Cooling System with Variable Speed Plant & Distribution

Abstract

In the present work, a generic component-based model is developed for large chillers. The modeling of each component of the chiller plant is based on first principles or empirical relations formulated to be valid over a wide range of operating conditions. The components include single-stage centrifugal compressor with capacity control inlet guide vanes, shell & tube evaporator and condenser, variable-speed compressor and water circulation pumps. The operational data was obtained through a SCADA (Supervisory Control and Data Acquisition) monitoring scheme for one of the 4-unit district cooling plant with a capacity of 2500 ton. The chiller uses R134a as refrigerant where the heat exchangers carry water inside the tubes and refrigerant flowing inside the shell. The model is able to predict capacity and input power at specified conditions. The plant model is then used to determine the optimal combination of control settings for a range of load and operating conditions.

Date of Award	Aug 2013
Original language	American English
Supervisor	Peter Armstrong (Supervisor)