Computer-Aided Evaluation of HVAC System Performance

Overview

Studies have indicated that 20-30% of energy savings in commercial buildings is achievable by re-commissioning of the HVAC systems to rectify faulty operation. Current strategies do not explicitly optimize performance and cannot respond to the occurrence of faults which cause performance to deteriorate. The objective of this project was to work with controls manufacturers, industrial partners and building owners and operators to demonstrate the benefit of computer aided fault detection and diagnostic systems. Methods were to be incorporated either in stand alone "PC" based systems or incorporated within a future generation of "smart" building control systems.

Research areas included:

Construct prototype performance validation systems

These were designed to assist with final stages of the commissioning or re-commissioning of HVAC systems. Test procedures were devised to check for correct operation and the absence of particular faults in the mechanical equipment and to assess performance.

Construct prototype performance monitoring systems

Monitoring systems were designed to detect unsatisfactory performance by comparing current performance with that predicted by a reference model. Different approaches to generate reference models were investigated.

Interface prototype systems to building control systems

Interfaces were designed to connect the prototype systems to commercial control systems.

Test and demonstrate performance validation and monitoring systems in real buildings

Field trials were carried out for both new, unoccupied buildings nearing completion and buildings which had been occupied for some time. Long- term monitoring also took place to determine their effectiveness in detecting and diagnosing faults that arise during normal operation.