The design process of HVAC (Heating, Ventilation and Air
Conditioning) systems is based upon selecting suitable components and
matching their performance at an arbitrary design point, usually
determined by an analysis of the peak environmental loads on a
building. The part load operation of systems and plant is rarely
investigated due to the complexity of the analysis and the pressure
of limited design time. System simulation techniques have been
developed to analyse the performance of specific commonly used
systems: however these 'fixed menu, simulations do not permit
appraisal of hybrid and innovative design proposals.
The thesis describes research into the development of a component
based simulation technique in which any system may be represented by
a network of components and their interconnecting variables. The
generalised network formulation described is based upon the
engineer's schematic diagram and gives the designer the same
flexibility in simulation as is available in design. The formulation
of suitable component algorithms using readily available performance
data is discussed, the models developed being of a 'lumped parameter'
steady state form.
The system component equations are solved simultaneously for a
particular operating point using a gradient based non-linear
optimisation algorithm. The application of several optimisation
algorithms to the solution of RVAC systems is described and the
limitations of these methods are discussed. Conclusions are drawn
and recommendations are made for the required attributes of an
optimisation algorithm to suit the particular characteristics of HVAC
The structure of the simulation program developed is given and the
application of the component based simulation procedure to several
systems is described. The potential for the use of the simulation
technique as a design tool is discussed and recommendations for
further work are made.
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.