Nonlinear observer design using contraction theory with application to heat exchangers having varying phase transition

Thermo-fluid systems such as air conditioning and refrigeration systems are widely used in residential, commercial, and industrial applications. By the end of the 20th century, nearly 70 percent of U.S. households had air conditioning, and 99.5 percent had at least one refrigerator. Advanced control and monitoring of the thermo-fluid systems has become an inevitable but challenging issue in this century as the energy efficiency has become increasingly important. Air conditioning and refrigeration systems transport heat by means of refrigerant, repeating phase transition, which is a highly nonlinear process. Mixture of vapor and liquid refrigerant distributed in heat exchangers makes the process dynamics highly complex, including many state variables that are important for stringent control but are not directly measurable. In this thesis, nonlinear observers for estimating those inaccessible state variables are designed and are applied to the control and monitoring of an air conditioning system. First heat exchanger dynamics including complex phase transition phenomena are analyzed. It is shown that the order of the system varies dynamically depending on the distribution of vapor and liquid, which makes the system a varying-order switched system.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Cheng, Tao, 1975-

Advisor dc:contributor.advisor

• H. Harry Asada.

• Aeronautics and Astronautics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/36177

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/36177