Commissioning of HVAC systems has potential for significant improvements in
occupant satisfaction, comfort and energy consumption, but is very labour-intensive
and expensive as practiced at this time. Previous investigators have capitalized on
digital control systems' capability of logging and storing data and of interfacing with
external computers for open loop control by developing methods of automated fault
detection and diagnosis during normal operation. Some investigators have also
considered the application of this technique in commissioning.
This thesis investigates the possibility of utilizing first principles and empirical
models of air-handling unit components to represent correct operation of the unit
during commissioning. The models have parameters whose values can be determined
from engineering design intent information contained in the construction drawings
and other data available at commissioning time. Quasi-dynamic models are developed
and tested. The models are tested against design intent information and also against
data from a real system operating without known faults. The results show the models
agree well with the measured data except for some false positive indications,
particularly in the damper and fan models, during transients. A procedure for
estimating uncertainty in the instrumentation and the models is developed. The
models are also tested against artificial faults and are able to detect all of the faults.
Methods of diagnosing the faults are discussed.
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.