Calculation of Heating, Ventilating and Air Conditioning with CFD

HVAC aims to make the thermal sensation more pleasant. We want to avoid drafts, to regulate the humidity and to reduce the effects of unbearable heat due to solar radiation with regards to energy consumption.

 

Streamlines exiting a supply grille

 Streamlines entering an exhaust grille

Noise reduction

The fan is usually the loudest component. The noise travels through the pipe-works and leaves through the supply grills, spreading into the room. The noise level of the fan is evaluated by the manufacturer. It is necessary to install sound absorbers; the choice of the sound absorber is based on assumptions and experience. 

3D CFD Flow simulation

The ventilation or the decontamination of a room or a building is important enough that it should be drafted at the beginning of the project. It is required to perform 3D Computational Fluid Dynamics calculations: this is the only way to estimate the volume flow and pressure drops and to visualize the flow and the dissemination of the contaminants. Using these results, the optimization potentials of the initial climatisation are visible. The optimum climatisation should be ensured and realized with a series of CFD calculations.
The most common causes for the imprecision of the calculation are leakage of the room or a difference in the construction and operation of the climatisation system.

less contamination

The principle of precaution against infections, microbiological or bacterial contamination, and pollutants requires the installation of a cleanroom. The proven method is to blow air from the ceiling and to withdraw it from the floor or from the base of the walls. This method should be implemented if the architecture does not forbid it. The simulation makes it possible to protect the designated clean area from impurities and/or to evacuate any impurities produced in the room. The final option to be considered is the placing of barriers in the room to protect from contamination.

The pressure in the room must set to a precise value, for example, minus 50 Pa. Therefore, some regulator valves must be used; the pressure throttlings generate additional noise. These valves must be set differently according to the seasons. A turbulent flow generates larger dissemination than laminar flow. Both flow types can be well calculated with CFD. For the operation room of a hospital, a laminar block is always installed with flow speeds of 0.3 – 0.5 m/s. CFD simulations are required during the planning phase for compliance with the contamination classes.

Visualisation of a turbulent flow

 
Velocity vectors in an operation room

Consulting for CFD flow simulation

We are a consulting company specialised in 3D thermal and flow calculations; for ventilation we use the commercial tools for cartesian mesh FloEFD and Solid Edge Flow Simulation; we can also generate a 3D-CAD model. We offer analysis of acoustics to evaluate the noise level in the room.
Due to a flexible and fast mode of operation as well as the use of modern tools, we can make you offers made to measure to a competitive price.