Ph. D. project plan in brief for Tor Arvid Vik

Project title: "Life cycle cost of natural and hybrid ventilation concepts". Ph.D. program title: "Natural and hybrid ventilation - concepts and consequences". Supervisor and program leader: Prof. Øyvind Aschehoug, Dept. of Building Technology, NTNU. Co-supervisors: Prof. Anne Grete Hestnes, Dept. of Building Technology and Prof. Per Olaf Tjelflaat, Dept. of Refrigeration and Air Conditioning at NTNU. Time Schedule: January 2000 - December 2002. Background and problem statement Natural ventilation technologies rely on wind and buoyancy and have been used for thousands of years. For many years now, pure mechanical ventilation systems have dominated. They offer a stable airflow and allow efficient heat recovery. However, they tend to use much electricity, they generate noise, and they are often difficult to clean and maintain. By using natural ventilation fluctuations in indoor temperature and air quality may be experienced, and efficient heat recovery is difficult to achieve. However, recent development in computer technology has enabled satisfactory control and prediction of airflow in natural ventilation systems. Moreover, the combination of natural and mechanical ventilation, so-called hybrid ventilation utilises advantages and eliminates drawbacks from both. At NTNU an interdisciplinary Ph.D. program is established in co-operation with Hydro Aluminium and the Norwegian Research Council. One part of the program is three Ph.D. studies; an architect, a civil engineer and an HVAC engineer who work together in a team, identifying ventilation concepts together and analysing the consequences of them in their respective fields of profession. The full time study started in January 2000 and will end in December 2002. There is some uncertainty related to whether the use of natural ventilation concepts can compete with conventional mechanical concepts and in which contexts it is recommended with respect to life-cycle costs (LCC). There is also a tendency to focus on the investments, neglecting the running costs. The main intention of this Ph.D. project is therefore to establish a calculation model and to calculate LCC for different natural ventilation concepts and compare with each other and with mechanical systems as references.

The LCC model should include issues such as heat recovery, airflow rate, cleaning, maintenance, fire and noise protection measures and area use. It should also enable a proper treatment of unreliable input parameters like durability of components, energy price and interest rate development. The main working method will be case studies of 3-5 buildings. The study will be limited to office and school buildings in Northern Europe. Objectives 1. To develop a model for calculation of LCC for natural ventilation concepts. 2. To investigate in which cases different natural ventilation concepts are recommendable with respect to LCC, compared with mechanical ventilation concepts. Main method   Parameter studies based on 3 existing hybrid ventilated buildings with different concepts. Strategy in brief 1. Provide brief information about - significance of different ventilation cost issues, and - uncertainty related to LCC 2. Identify and sort ventilation concepts and conditions. 3. Develop LCC calculation model by means of case studies. 4. Use case study buildings as a base for simulation of other concepts or solutions. 5. Draw general conclusions from the case studies and simulations. Proposed thesis contents in brief 1. Introduction. 2. Definitions, etc. 3. Ventilation concepts. 4. The role of costs in the decision process. 5. Ventilation cost issues. 6. Method 7. LCC of Grong school 8. LCC of B&O 9. LCC of GSW 10. Implementation of LCC in daily design work 11. Discussion and sensitivity analysis 12. Conclusions 13. References

Tor Arvid Vik, M.Sc., Ph.D student, Department of building technology, NTNU, Trondheim, Norway E-mail: tor.a.vik@ark.ntnu.no URL: http://www.ntnu.no/arkitekt/bt/ansatte/vik.html          (Revised: Nov.2001 - iw)