For a ventilation system in any industrial environment, meeting process requirement efficiently along with human comfort is a rare possibility; often they are over designed to compensate for any hidden issue in the design itself. These systems does the work but at a higher cost as they are not optimized for efficient performance and energy saving. In general industrial environment contaminant control, human comfort and energy efficiency are main requirement of HVAC system. For pharmaceutical and food industry meeting the process requirement of specific temperature and humidity with human comfort is difficult to achieve and mostly results in over-sized HVAC equipment and inefficient system. CFD analysis helps to evaluate the air distribution inside the concerned space and achieve process requirement efficiently with human comfort and contaminant control.
Case study: CFD analysis for the industrial ventilation. Air distribution is done by the fabric ducts
The goal of analysis was to analyse air system for a factory shed in order to provide comfortable environment for workers inside and also achieve the necessary requirements of process in specific areas in terms of temperature and humidity. The CFD analysis and project results provide an overview of this project.
Proper air distribution is to be maintained with the installed system.The following criteria were to be met by the newly designed system:
– The temperature of around 23.9 0C is to be maintained at all times.
– Relative humidity of about 55% is to be maintained in the area.
– Meeting a Process specific requirement of temperature and humidity.
The 3D model for simulation was prepared as per the architectural drawings and layout received. Heat loads from equipment, occupants, solar load were assigned. Air conditioning systems was modelled as per the HVAC drawings.
Based on the results of the steady state CFD simulation, we were able to conclude as follows:
The average velocities obtained at the height of 1.5m is 0.53 m/sec, which shows that there is proper air distribution inside the factory.
-Temperature range obtained at the height of 1.5m in the occupants area is 22.0-29.00 degC & near to the equipment machinery it was 34 degC. These higher temperatures obtained near the machinery are mainly due to higher heat loads from the equipment and able to meet the process requirement.
-Relative humidity obtained at the height of 1.5m ranges from 38% to 57% at hot spots near the machinery & 38% to 53% around the machinery. Which shows that near & around the machinery the relative humidity was close to design relative humidity of 55 %.
– Pressure Losses obtained in the duct near the AHU Supply are as Section-1 (15000 CFM) = 197 Pa, Section-2 (25000 CFM) = 195 Pa, which is close to the static pressure available from the AHUs,
Based upon the above data the system was assured with to meet the process requirement as well as the human comfort criteria with the minimum airflow and static pressure requirement.