EBC Annex 25 Real Time HEVAC Simulation


Status: Completed (1991-1995)

Operating Agent: Prof Reijo Kohonen, ABB Installaatiot Oy, Takomotie 8 A, Postfach 181, FIN-00381 Helsinki, Finland.
Tel: +358 0564 8196
Fax: +358 0564 8180
Email: reijo.kohonen[at]fiins.abb.fi



In the near future, the most promising energy saving measures are in advanced control and operational technologies. Lowest energy consumptions, one of the basic factors for reducing managing costs, will be reached together with well-organised maintenance, fast detection and correction of defects and best use of equipment performances. Thus the reliability, availability and the efficient use of the HVAC and control systems will be emphasised in the use and maintenance of buildings.

Partly these characteristics can be affected by integrated planning and product development. Another and parallel way is to develop methods for the real time analysis of the performance of HVAC processes and for the fault detection and diagnosis. The main goal of the Annex was to develop methodological procedures within a defined concept for real time and automatic performance optimisation, diagnosis and fault detection of HVAC processes. The ultimate goal of the project was BOFD prototypes that are implementable in Building Energy Management Systems. Part objectives of the Annex were:


To evaluate the best (most suitable) modelling approaches for the real time simulation of HVAC systems.

To develop methods for the qualitative availability analysis of HVAC systems.

To collect a data base of the most important troubles and faults in HVAC systems.

To demonstrate the implementation of the concepts in conjunction of a real BEM system.

The Annex concentrated on the energy performance diagnosis of a building and HVAC systems and the fault detection of HVAC components and subprocesses.

Main achievements:


A general BOFD system concept paper.

A classification of BOFD methods (draft report).

Reference systems; list of typical faults; and ranking of faults.

First applications of selected BOFD methods.

Test rigs.

New component and fault models.

Prototype expert system cell.


Participants: Canada, Germany, Finland, France, Japan, Netherlands Switzerland, UK, USA

Observers: Belgium, Italy, Sweden



Technical Synthesis Report: Real Time Simulation of HVAC Systems for Building Optimisation, Fault Detection and Diagnostics
by M W Liddament
UK, Coventry, ESSU, (Air Infiltration and Ventilation Centre), 1999, 34 pp
Order Printed Copy £20.00 (Order Code: ANN 25 TSR)  Download (1.6 Mb)

Operational faults in HVAC systems continue to impact on building energy performance and often result in adverse comfort conditions. The main objective of this study was to develop real time procedures to monitor and optimise HVAC performance. Activities covered:
- Evaluating modelling performance for the real time simulation of HVAC systems;
- The compilation of a database of important troubles and faults in existing systems;
- Demonstrating the implementation of building optimisation, fault detection and diagnosis (BOFD).

Final Report Vol 1: Building Optimization and Fault Diagnosis Source Book
Hyvarinen J, Karki S (eds.)
Finland, Technical Research Centre of Finland, Building Technology, 1996, 324 pp  Download(8.6 Mb)
The final report of this annex consists of two volumes: Volume I, Source Book ,and Volume II, Technical papers.

The source book describes the basic concepts and the fault detection and diagnosis approaches applied in the project. A part of the book contains discussions of building optimisation, fault detection and diagnosis, the reasoning process, building optimisation and fault diagnosis system components, system structure, and system implementation. A major part of the source book is devoted to important faults of typical HVAC systems. Most of the annex research work is described in sections discussing various fault detection and diagnosis approaches. Also a part of the book discusses general tools needed in building a fault diagnosis system.

Final Report Vol 2: Technical Papers of IEA Annex 25
Hyvarinen J (ed.),
Finland, Technical Research Centre of Finland, VTT Building Technology, 1997, 754 pp  Download (20 Mb)
This report describes the technical and scientific work carried out in Annex 25, and the applications developed during the Annex. It consists of three parts: system applications, method applications, and tools. The parts and sections in the volume are written as separate technical papers, reviewed and only published together without any further editing.