Ventilation systems

Calculating the thermal comfort

A CFD simulation calculates the indoor climate of a room in detail. The simulation accounts for all influences, such as solar radiation, internal and external heat load and of course the ventilation system itself. Parameters such as temperature, air velocity, CO2 concentration and others are calculated at every location in the room. Optionally, derived variables such as PMV/PPD, based on EN-ISO 7730, or operating temperature, based on ASHRAE 55, can be calculated.

Calculating the air quality

For spaces such as factories or clean rooms, comfort parameters are not the most important factors, but air quality is. Specific air properties, such as temperature or humidity, are required for certain production processes, for example when painting ships in a yard. Clean rooms often have a very high air change rate, but it is important that no air can escape from the cabinets. With CFD simulations, the design of a ventilation system can be tested and optimised in an early stage.

Calculating the air distribution

The air distribution in a room can well be calculated by means of a CFD simulation. This is important in, for example, an operating theatre where air is blown into the room through a plenum above the patient. Air must not be contaminated by personnel or other equipment before reaching the patient. CFD simulations are also often used for data centres to verify the distribution of chilled air over the many racks present. In addition, on the roof of a data centre there often is a large amount of cooling equipment that can affect each other (short circuit), making them work less efficiently.

Design and optimize

With a CFD simulation, the design of a ventilation system can be analysed and optimized at an early stage. Different systems can easily be compared in the design phase in a digital test environment. The effectiveness of natural ventilation systems relying on pressure differences created by wind or on temperature differences can well be simulated.