Engineering Simulation for Built Environment and HVAC Design

Thermal comfort and indoor air quality are the primary objectives of Heat, Ventilation and Air Conditioning (HVAC) design for buildings, vehicles and other environments.  Predicting room conditions such as air velocity, temperature, relative humidity, thermal radiation, contaminants that are affected by ventilation, heat loss and solar gains through the structure walls, roof, floors, windows, and doors, and by the presence and activities of people and equipment in many types of buildings provides information that is required for design improvement, optimization and energy efficiency.

Building design for ventilation and comfort can be greatly facilitated through simple air flow modeling that helps engineers and architects to quantify and visualize the impact of structural modifications to equipment on occupants’ thermal comfort. Frequently, complex geometry needs to be addressed, often with curved surfaces.  Software from ANSYS offers powerful geometry and meshing utilities, with flexible interfacing to CAD data. Engineered scalability provides the right level of engineering performance, ranging from simplified analyses to the most complex simulations where comprehensive multiphysics -- mechanical and thermal behavior of a structure, multiphase phenomena with condensation or sprinklers and acoustic modeling -- might be involved.

Our software includes RANS and LES turbulence models and state-of-the-art gray and spectral radiation solvers that can consider shortwave and longwave radiation, window performance, shading and solar gain in general. Conjugate heat transfer capabilities are available, as well as full one-way and two-way thermal and mechanical coupling of separate fluid and structural models (fluid structure interaction, or FSI). The latter allows assessment of wind-induced distortion and vibrations.

The unequalled technical depth within many simulation domains and the unparalleled breadth reaching across multiple engineering simulation disciplines, in an open and integrated environment, facilitate the effective design of public buildings. Comfort modeling in a stadium with an adjustable roof presents a mechanical challenge coupled with complex varying air flow.  Hockey or ice-skating arenas require a combination of freezing conditions close to the ice while maintaining a comfortable environment in public areas that may hold a large number of people. The position of HVAC equipment needs to be optimized to maintain ideal conditions in concert halls or theaters, and maximum temperatures in data centers need to be guaranteed.

Using such simulation results coupled with information about the activity and clothing of occupants, designers can compare against a variety of comfort criteria. This is particularly valuable in testing the effectiveness of novel strategies and concepts including natural and mixed-mode ventilation. It is also important in minimizing energy consumption through the improvement of building materials, informed choice of the available HVAC equipment and through optimization of the building design.

As energy costs increase, engineering simulation allows the designer and operator of a building to balance the ventilation required to provide a comfortable indoor environment against the need to keep energy costs under control.  Architects and engineers, who design for code compliance, fire suppression or emergency procedures rely more and more on engineering simulation solutions.

Predicted local humidity levels on a plane near the main wall paintings of the tomb of Ramses VII with a representative adult male tourist figure; the sarcophogus is in the foreground.
Courtesy Cairo University, post-processing courtesy Maciej Ginalski.

Air conditioning in a data center

Courtesy of GTD GmbH and University of Sheffiel