Building Climate / Energy Efficency
The design of energy efficient buildings requires a profound understanding of the transport processes of heat and humidity between the building's interior and its surroundings. Especially in modern architecture, attention has to be given to the flow around a building and the consequences this flow has on the climate of the inner rooms. Along the outer wall of the building transport parameters show great differences if you compare areas with stagnating flow to regions of high, impinging flows. The spatial differences of these flow parameters can be taken into account with the methods of numerical fluid dynamics (CFD). In these numerical calculations manifold time dependent boundary conditions, like wind direction, wind speed, air humidity and ambient temperature, sun intensity and the different radiation properties of each wall surface can be considered.
To achieve a high degree of energy efficiency, the walls of the building have to keep as much heat inside the building as possible, whereas there should be no condensation of water in any wall region at any given time or weather condition. Conventional methods to calculate the buildings climatic properties are often restricted to one-dimensional problems like the transport processes through a flat wall in a stationary system. With CFD, complex systems can be analysed on the basis of a realistic three dimensional geometry model and transient calculations can be performed which cover time scales of weather conditions of days, weeks or even months.
With the methods of numerical simulation, information on flow, heat and humidity parameters in the building's interior can be gathered already during the planning process. This opportunity helps architects, clients and engineers to find a favourable configuration for a building project.
As a result, an optimised concept for heating, ventilation and air conditioning can be developed. On the other hand, various architectural design concepts can be benchmarked taking into account air flow and thermodynamic characteristics.
