The comparison between air change efficiency and contaminant removal effectiveness under some typical air flow conditions in the room ventilated mechanically.

There are many indices to evaluate the ventilation characteristics of the ventilated rooms. These indices are classified into air change efficiency and contaminant removal effectiveness. In order to know how to use many indjces for a good understanding of the characteristics of the concerned ventilation system, the values of various efficiencies under some typical air flow conditions with isothermal condition are compared. The local mean age distributions and local contaminant concentrations are measured with tracer gas technique in a scaled model of the room ventilated mechanically.

Airflow patterns in Schonbrunn Palace.

The purpose of this study is to find more information of the complicated air flow pattern in the SchOnbrunn palace. The aim is to improve the control of the air infiltration. We have used a passive tracer gas technique, a special case of the constant injection technique, called the homogeneous emission technique. The results gives Air Change Rate's (ACH) of 0,7 to 1,7 in different rooms and parts of the palace. Wind driven ventilation dominates stack driven ventilation. We found a considerable air flow between floors.

Turbulent force flow in an airblast storage room.

Forced air circulation in a storage room either with freezing/cooling or controlled atmosphere is usually turbulent because a high air change rate is generally required. The interaction between the turbulent air flow and the product layers plays an important role in the performance of the storage room. In this paper, a homogenous model based on the Brinkman-Forchheimer-extended Darcy equation for both fluid and porous layer is described, in association with the standard k-e turbulence model.

Performance appraisal of a ventilation system - a comparison of two methods.

The performance of a ventilation system, particularly that which is incorporated in centralised air-conditioning system, can be evaluated in several ways. The "ventilation efficiency and ventilation effectiveness" and "air exchange efficiency" are two of the most commonly employed methods in ventilation analysis.