modelling

The paper considers issues pertaining to the capabilities and limitations of computational methods for multidimensional turbulent flows of the type encountered in fluids engineering. It argues that CFD, whilst offering considerable predictive power and potential, is not yet sufficiently well established to be applied routinely to complex 3D flows, unless only a rough qualitative. statement is being sought.

In order to evaluate the accuracy of COMIS predictions for large openings,and to study its sensitivity, two tests have been performed. In the first test, COMIS is used together with four existing multizone air flow models to calculate natural ventilation in a building for various climatic and opening configurations. In the second test, COMIS predictions are compared with single-sided ventilation measurements taken in test cells. The results of the tests are reported.

A sudden contamination of the outdoor air by some toxic gas can have several causes. To find out the protection afforded by sheltering indoors was the primary goal of the investigation. The object of the computational approach was a single family house with 2 floors. Three different models were utilized to calculate the infiltration air flows, the contaminant transport inside the building and the temperature decay of the building.

The computer model SIN-BIP is built as a combined model that can calculate energy consumption, price and environmental load for a building to get an energy efficient building. The program has a database with information of price, thermal conductivity, moisture conductivity, energy content and CO2-emission for materials. On the basis of this information can the program calculate for each construction, the U-value, the moisture resistance (and if there is condensation), the price, the energy used for producing the material and the environmental load from CO2-emission at the production.

Parking garages require ventilation because the exhaust fumes produced by the vehicles have to be discharged. This can be achieved with a mechanical or a natural ventilation system. A natural ventilation system has several important advantages compared with a mechanical system. As a rule natural ventilation systems arc simpler, cheaper and have fewer breakdowns, furthermore a natural system requires less maintenance and uses no energy (for air transfer).