A TRNSYS Component to Calculate Natural Ventilation and Indoor Air Quality in Multizone Buildings

The prediction of air infiltration is very important when simulating a building, due to the couplingaspects of the thermal and ventilation problem. So, the development of codes capable of performingsimple yet precise calculations is of great usefulness. Their utility can even be enlarged if we addsubroutines capable of air quality calculation and automation of some preliminary but necessaryassessments, like local pressure coefficients over the building facades and wind speed profiles. Such code can be compiled to be run under a well-known simulation environment like IISiBat/TRNSYS, where the coupling of thermal and ventilation problems can be held. This paper describes a computer application that was developed using these concepts. It was developed in Delphi and was divided in two modules. The first one is a stand-alone application used to generate the description files necessary to the second module. The second module is a DLL file compiled as a TRNSYS component. Inside TRNSYS, the module reads the building description files saved by the interface application and then calculates air infiltration and air quality for every time step of the simulation.Firstly, the assumptions used to develop the TRNSYS component are described. Next, the programutilization is presented.