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Decentralized model predictive control of a multiple evaporator HVAC system

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dc.contributor.advisor Rasmussen, Bryan P. en_US
dc.creator Elliott, Matthew Stuart en_US
dc.date.accessioned 2010-01-15T00:07:33Z en_US
dc.date.accessioned 2010-01-16T01:11:25Z
dc.date.available 2010-01-15T00:07:33Z en_US
dc.date.available 2010-01-16T01:11:25Z
dc.date.created 2008-08 en_US
dc.date.issued 2009-05-15 en_US
dc.identifier.uri http://hdl.handle.net/1969.1/ETD-TAMU-3001
dc.description.abstract Vapor compression cooling systems are the primary method used for refrigeration and air conditioning, and as such are a major component of household and commercial building energy consumption. Application of advanced control techniques to these systems is still a relatively unexplored area, and has the potential to significantly improve the energy efficiency of these systems, thereby decreasing their operating costs. This thesis explores a new method of decentralizing the capacity control of a multiple evaporator system in order to meet the separate temperature requirements of two cooling zones. The experimental system used for controller evaluation is a custom built small-scale water chiller with two evaporators; each evaporator services a separate body of water, referred to as a cooling zone. The two evaporators are connected to a single condenser and variable speed compressor, and feature variable water flow and electronic expansion valves. The control problem lies in development of a control architecture that will chill the water in the two tanks (referred to as cooling zones) to a desired temperature setpoint while minimizing the energy consumption of the system. A novel control architecture is developed that relies upon time scale separation of the various dynamics of the system; each evaporator is controlled independently with a model predictive control (MPC) based controller package, while the compressor reacts to system conditions to supply the total cooling required by the system as a whole. MPC’s inherent constraint-handling capability allows the local controllers to directly track an evaporator cooling setpoint while keeping superheat within a tight band, rather than the industrially standard approach of regulating superheat directly. The compressor responds to system conditions to track a pressure setpoint; in this configuration, pressure serves as the signal that informs the compressor of cooling demand changes. Finally, a global controller is developed that has knowledge of the energy consumption characteristics of the system. This global controller calculates the setpoints for the local controllers in pursuit of a global objective; namely, regulating the temperature of a cooling zone to a desired setpoint while minimizing energy usage. en_US
dc.format.medium electronic en_US
dc.format.mimetype application/pdf en_US
dc.language.iso en_US en_US
dc.subject MPC en_US
dc.subject HVAC en_US
dc.title Decentralized model predictive control of a multiple evaporator HVAC system en_US
dc.type Book en
dc.type Thesis en
thesis.degree.department Mechanical Engineering en_US
thesis.degree.discipline Mechanical Engineering en_US
thesis.degree.grantor Texas A&M University en_US
thesis.degree.name Master of Science en_US
thesis.degree.level Masters en_US
dc.contributor.committeeMember Culp, Charles en_US
dc.contributor.committeeMember Palazzolo, Alan en_US
dc.type.genre Electronic Thesis en_US
dc.type.material text en_US
dc.format.digitalOrigin born digital en_US

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