English

The Building Air Tightness is an important parameter on ventilation systems performanceand energy losses.Yet, the total amount of leakage is as important on performances as their effective positionin the room.Some calculations have been run according to prEN 13465 from TC156 WG2 for differentbuildings (single house, dwellings and commercial buildings) varying air tightness, valueand repartition for different ventilation systems (natural, mechanical exhaust, mechanicalexhaust and supply).All these calculations have been compared focusing on ventilation losses during heatingseason in Paris.So

In natural ventilation systems, fresh air is often provided through opening of windows, andthere is a wide range of possibilities with regard to selection of window type and position inthe facade. Different window types have quite different characteristics and thereby differentimpact on the thermal comfort conditions in the occupied zone. The thermal comfort is alsovery dependent on the selected natural ventilation strategy, the outdoor conditions and theavailable pressure difference across the window opening.

The operation and performance of forced-air ventilation systems with the aid of a dynamic modeling and simulation computer program are presented. The functions and features of GEMS (Generalized Engineering Modeling and Simulation), a dynamic modeling and simulation software tool, are briefly described. Using GEMS, the effects of different ventilation airflow rates and sensible and moisture efficiencies on the thermal comfort environment within the conditioned space were analyzed.

The development of guidelines for performance based innovative mechanical ventilationsystems in residential and commercial buildings is included in the European Commissionproject TIPVENT Towards Improved Performances of Mechanical Ventilation Systems.The overall aim of TIPVENT is to promote improved performances of mechanical ventilationsystems and the introduction and implementation of innovative designs. The development ofperformance oriented procedures for designing, commissioning and maintaining mechanicalventilation systems plays a key role in the project.

A number of single tracer gas techniques (decay, step-up, homogeneous constant emission,inlet pulse and homogeneous pulse) suitable for measuring the local mean ages of air in multizonebuildings exist, each having their advantages and drawbacks. The characteristics of thedifferent available techniques are compared from theoretical and practical points of view. Thehomogeneous pulse technique has not been experimentally validated before. This techniquerelies on pulses of tracer gas being injected into the different zones in amounts, which areproportional to the zone volumes.

This paper presents an experimental study of natural ventilation induced by combined forces of thermal buoyancy and opposing wind in a single-zone building. Experiments demonstrated that for a certain range of buoyancy strength and wind speed, two different stable ventilation modes and thus flow rates exist for a fixed building geometry at given buoyancy and wind strength. In these situations, the final ventilation mode and the ventilation flow rate are dependent on the ventilation history of the building.

The traditional way to dehumidify the outdoor air in an A/C-system is by cooling the air downbelow the dew point temperature. For this process a refrigeration system is necessary torealise these low temperatures. Nowadays the disadvantages of refrigeration systems fordehumidification are widely known. An alternative method to dehumidify the air is byseparating the process of dehumidification and cooling.The paper will present a testing plant of 1200 m air/h which is installed in the University ofEssen. This A/C-systems works with liquid desiccants.

Conventional models of building occupants' environmental preferences such as thermal comfort are used to give guidelines for the average environmental conditions that will satisfy large groups of people. The research described in this paper investigates how the preferences of an individual occupant can be modeled to predict their preferred thermal and environmental conditions. A novel, Internet based questionnaire was developed to gather thermal sensation votes.

The relative importance of ventilation in the energy balance of buildings has been increasing,as a consequence of control of heat exchanges through the envelope and internalgains. It is therefore very important to clearly understand the main factors that affect energyconsumption due to ventilation and potential ways to decrease the energy demand withoutaffecting IAQ.This study was developed within the European project TIP-VENT (JOULE).

The paper presents a short description of the measurement program and the data collected for the “SynergieHaus”-project initiated by PreussenElektra and partners (now merged to E.ON). Results of airtightness measurements (ACH 50-values) are shown for a to