E.Vent – Efficient, cost-effective and low-maintenance central ventilation systems for multi-family housing – Design, operation and fire protection measures

Central ventilation systems offer great advantages especially in multi-family and multi-storey residential buildings. However, due to increased costs or complexity caused by necessary fire protection measures and the need for maintenance, solutions are often implemented that can at best be described as suboptimal in terms of efficiency, balance and fire protection.

The aim of this project is to develop innovative solutions for fire protection and continuous balance adjustment while reducing costs for central ventilation systems in both new buildings and refurbishments. Planning tools for the early design phase are developed and implemented in a 3D graphic tool. Space requirements, volume flows and pressure losses are characterized and recommendations for the design of efficient central ventilation systems are made.

Based on an investigation and stock analysis the requirements for fire protection were clearly defined. The possible applications of different fire protection components such as fire dampers, FLI-VE and cold smoke barriers were examined and evaluated in detail. Different solutions in the European area were considered as well. Innovative fire protection concepts were developed and evaluated by authorized experts. These concepts have already been implemented in several projects, both in Innsbruck and Graz. The focus in the development of the concepts was on cost efficiency, low pressure losses due to the components used and the lowest possible maintenance effort.

Evaluations of the balance adjustment in various objects in Graz and Innsbruck were carried out, assessed and problem areas were found on the basis of measurements of the actual balance in single apartments and at the central unit, each with different volume flow control concepts. Solutions for balance adjustment ranging from low-tech (passive, without electrical drives) to high-tech (electrical/mechanical, optimizer) were investigated.

To check the balance adjustment, a highly accurate volume flow measurement is required, as it is the difference between the absolute values of the supply and extract air or the fresh air and extract air volume flow. For this purpose, a measuring device, called a Riesenflowfinder, was designed and set up in the project to enable the precise measurements to be carried out at all. Several methods of balance adjustment were evaluated: Automatic balance adjustment using volume flow controlled fans, apartment balance adjustment using variable active volume flow controllers, and also apartment balance adjustment using passive constant volume flow controllers or volume flow limiters.

The measurements showed imbalances in almost all buildings. The air volumes transported on different days or at different times of the day varied considerably and the balance of the overall systems had to be checked and readjusted to avoid major deviations.

Possible synergies between fire protection (cold smoke barrier) and volume flow control were used and a functional model was developed. An integration of the cold smoke barrier function in the volume flow controller is technically feasible, resulting in advantages such as the elimination of a mechanical component in the ventilation system or energy savings of at least 10% due to lower pressure losses in the ventilation system.

The development of the planning tool was divided into two steps: First, a very simple version in the form of an Excel tool was implemented, which includes the rough general conditions as well as fire protection. Based on this tool, a test implementation in a 3D CAD application was developed as a planning assistance. It includes the determination of the necessary volume flow including the dimensions of the ventilation shaft, the space required for the ventilation unit is calculated and the optimal ventilation unit is suggested.

The Excel tool offers the user an overview at a very early planning stage of which ventilation variants and fire protection concepts are possible at all. It is not necessary to know all the details of the building. The tool provides a rough estimate of the investment and maintenance costs of fire protection as well as the pressure loss and efficiency of the ventilation system. The implementation of the 3D CAD application as a test version could be realized. This tool facilitates decision making during the design process and subsequently enables better economy and higher efficiency, not only of the ventilation system but of the whole project. However, a real application should be accompanied by further detailed development work.

Conclusion

In this project, innovative fire protection concepts have been developed and implemented in projects that offer significant progress in efficiency and economy. The development of the combination of cold smoke barrier and volume flow controller offers new opportunities to make the systems even more efficient. In various projects the balance adjustment could be assessed and greatly improved by means of new measuring systems. However, especially in the case of low volume flows the market does not yet offer any corresponding passive volume flow controllers; the aim here is to develop suitable solutions with sufficient accuracy. The developed planning tools offer a strong decision support, especially in the early planning phase, to improve the economy and efficiency of the systems. Further development for real application would offer great advantages for planners and building owners.

Project management

Universität Innsbruck, Arbeitsbereich Energieeffizientes Bauen EEB

Project or cooperation partners

• AEE - Institut für Nachhaltige Technologien (AEE INTEC)
• J. PICHLER Gesellschaft m.b.H. (Pichler)
• Innsbruck Immobilien Gesellschaft (IIG)
• Neue Heimat Tirol (NHT)
• Gemeinnützige Alpenländische Gesellschaft für Wohnungsbau und Siedlungswesen m.b.H. (GWS)
• Alpsolar Klimadesign OG (AlpSolar)
• Passivhaus Institut – Standort Innsbruck (PHI-IBK)

Assoz. Prof. Dr. Rainer Pfluger
Technikerstrasse 13
A-6020 Innsbruck
Tel.: +43 (512) 507-63602
E-Mail: Rainer.pfluger@uibk.ac.at
Web: https://www.uibk.ac.at/bauphysik/,
Web: https://www.uibk.ac.at/bauphysik/forschung/