Car-Park Ventilation, Carbon-Monoxide Modelling
Carbon monoxide control is a major challenge in covered car parks. In absence of proper ventilation system, parking facility presents several Internal Air Quality problems. Most serious is the emission of high levels of Carbon-Monoxide(CO) and is easily absorbed by Haemoglobin in Human Blood and can Inhibit Oxygen delivery to Body and can cause adverse health effects varying from headache to death. Thus design of ventilation system should have adequate air movement inside the basement when operating under normal conditions; should be able to satisfactorily extract CO produced from vehicles.
By using CFD analysis we ensured that the ventilation system meets the NBC, ASHRAE and WHO guidelines for CO exposure and contaminant control etc. The working of staircase pressurization, zone modelling for CO removal can also be analysed. For a large car park the zoning can also be done so as to ensure operation of minimum fans to remove the CO. This ensure the energy saving in long run and best energy efficient system.
The main objectives are listed below:
-To investigate the performance of the system, so that there is adequate air movement throughout the car park under normal operating conditions.
-The event of a CO high level (>100 PPM) is avoided at short term exposure of 30 min .
The acceptance contaminant level criterion for parking garages is recommended in ASHRAE 2007 Handbook. According to ASHRE, the main criterion for park is the carbon monoxide level is to remain below a designated peak value. ‘Parking garages ventilation rate designed to maintain a CO level of 40 mg/m3 (35 ppm) for 1 Hour exposure, with a maximum of 130 mg/m3 (120 ppm) for 15 minute exposure’.
The output of analysis in in the form of report containing velocity profiles, temperature and CO profiles at different planes. In addition the compliance summary with the standards is also provided.Below pictures show the results of CO simulation in Car park.
Ductless ventilation with Axial Jet Fans. Click pictures to enlarge.