A design tool for natural ventilation.

A difficulty when designing natural ventilation in office buildings is the lack of simple designtools.In order to be able to predict natural ventilation air flow rates and indoor air temperatures atthe design stage, a computer model has been developed within the EU-JOULE projectNatvent (TM). The program is an integrated model with a thermal and an air flow modelcoupled together. It can be used early in the design process to determine possibilities andrestrictions in the use of natural ventilation in an office building.The most important objectives while developing the program have been to create a robustunderlying theoretical model and an easy-to-use interface. Set in the Windows environment,the required input data are easily overviewed at all times. A key issue has been to use indatawhich are easy to quante, even at an early stage in the design process.The paper discusses briefly the theoretical model as well as the Natvent (TM) computerprogram.The program will be subject to extensive user tests during the autumn of 1997 and will bereleased in the spring of 1998.