Modeling and construction of a computer controlled air conditioning system

by Frink, Brandon S.

Abstract (Summary)
As energy efficient devices become more necessary, it is desired to increase the

efficiency of air conditioning systems. Current systems use on/off control, where the unit

primarily operates in the long lasting start up transients. A proposed solution is an air

conditioning unit that runs continuously with active computer control implemented to

maximize efficiency. The objective of this thesis is to develop a mathematical model for

a specific air conditioning unit and to compare this model to measurements made on the

specific unit. This model can then be used to develop a multi-input multi-output control

law in the future.

In this thesis, a linearized moving interface lumped parameter model is presented,

and the derivation verified with great detail. The model predicts transient perturbations

from a steady state operating point. The air conditioner tested in this work required

several modifications including the addition of sensors and controllers. A description of

the system is provided. Methods used to determine all of the parameters for the model

are given with explanation. The model is simulated with computer software and

compared with experimental data. Simulations predict the final value of superheat and

pressures in the evaporator and condenser well for step changes in the compressor speed

and expansion valve opening.

Bibliographical Information:


School:Kansas State University

School Location:USA - Kansas

Source Type:Master's Thesis

Keywords:refrigeration model engineering mechanical 0548


Date of Publication:01/01/2007

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