The workable design of HVAC (Heating Ventilating and Air Conditioning)
systems is based upon sizing the components individually to meet a
peak duty of a nominal operating point. Growing economic pressure
demands more cost effective and efficient designs, but the appraisal
of alternative solutions is limited by short design and construction
times. The design of HVAC systems can benefit from the application of
numerical optimisation methods as these allow the rapid appraisal of
alternative schemes and the sizing of the components simultaneously
for criteria such as minimum first cost, operating cost, life—cycle
cost or primary energy consumption.
Optimisation problems can be categorised according to the
characteristics of the functions used to appraise the solutions and
those of the constraints on the problem. This thesis discusses the
formulation of EVAC system design problems in this context and
describes the development of an optimisation procedure which is based
upon a data base of manufactured components and operating parameters
such as controller setpoints, mass flow rates and temperatures. The
thesis describes several objective functions used in the appraisal of
solutions and describes the use of constraint functions in restricting
the solution to a practicable design.
UVAC system optimised design problems can be solved using direct
search methods. The implementation of three direct search algorithms
is described and the limitations of each discussed. Conclusions are
drawn and the characteristics of HVAC system optimised design problems
used to make recommendations for the future development of an
The thesis describes the development and structure of the optimised
design program and its integration with an existing suite of
simulation programs. The application of the program to the design of
example heat recovery systems is given and the potential use of the
software in other applications described together with proposals for
the development of the procedure as a design tool.
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.