# For HVAC applications : CFD is reliable and cost effective design tool



## Praful Dandgawal (May 28, 2013)

The building sector currently accounts for about one third of the energy consumption worldwide and much of this consumption is directly linked to building design and construction. Building energy consumption keeps rising in recent years due to growth in population, increasing demand for healthy, comfortable and productive indoor environment, global climate changing, etc. Most of the energy usage in buildings is for the provision of heating, ventilation and air conditioning (HVAC). High-level performance of HVAC systems in building lifecycle is critical to building sustainability. Hence a need of accurate and cost effective design tool which will help in designing the highly efficient system. 

*Computational Fuid Dynamics most commonly know as CFD,* has been emerged as one of the best design tool. CFD modeling can predict flow field and heat transfer which is the essential component of HVAC and sustainable (green) buildings. CFD when applied to buildings can provide the designer with information on probable air velocities, pressures and temperatures that will occur at any point through a predefined air volume in and around building spaces. Boundary conditions are specified which may include the effects of climate, internal heat gains and HVAC systems. 

*Key role of CFD in Building HVAC *

• External CFD analysis provides the distribution of air velocity and pressure around building structures due to the wind effect and this information can be used to assess pedestrian comfort, determine local pressures for positioning HVAC intakes/exhausts. 

• Internal CFD analysis provides information on the distribution of air velocity, pressure and temperature (and several other calculated parameters) throughout the inside of building spaces. 

• It helps us to determine thermally comfortable environment with acceptable indoor air quality by regulating indoor air parameters, such as air temperature, relative humidity, air speed, and chemical species concentrations in the air. 

• This information can be used to evaluate the effectiveness of various HVAC and natural ventilation system designs and to estimate consequent interior comfort conditions.

• CFD costs much less than experiments because physical modifications are not always feasible. The system with suggested modifications can be simulated computationally without actual physical modifications to the existing systems. CFD helps in studying “what if” scenarios.

• CFD data can be utilized to validate various design parameters such as the location and number of diffusers and exhausts, and temperature and flow rate (CFM) of supplied air to meet design criteria.


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