CH-95-16-4 --Computer Simulation of Ventilation Strategies for Maintaining an Acceptable Indoor Air Quality in Office Buildings PDF

Evaluates the effects of various ventilation strategies on contaminant distribution in a 22-storey office building for two events - 1. a partial renovation event, when a part of an occupied building is renovated and 2. a scheduled shutdown event, when the HVAC systems are shutdown during a holiday or a weekend. A multizone air and contaminant flow model was used to predict contaminant distribution. The model calculates pressures, air flows, and the time-varying contaminant concentration in the zones of a tall building. For a partial renovation event, the ventilation strategies included venting the renovated zone using window(s), a stairwell, a smoke control shaft, and mechanical exhaust. For a scheduled shutdown event, typical building operation was assumed with no specific source zone in the building. The objective of the computations was to determine the required start-up time of the HVAC system to diminish accumulated pollutant concentration in the building following a scheduled shutdown. Computations were conducted for winter, spring, and summer outdoor conditions. The effectiveness of various ventilation strategies for minimising the spread of the contaminant from the renovated zone to the surrounding areas depends on the location of the renovated zone with respect to the neutral pressure plane in the building. For the building used in the study, based on an outdoor air supply rate of 0.94 ACH, a four-hour start-up of the HVAC operation is adequate to diminish accumulated pollutant concentration in the building after a scheduled shutdown.

KEYWORDS: year 1995, calculating, ventilation, air quality, indoor, offices, air pollution, air flow, pressure, content, shutdown periods, building services, air infiltration, mechanical ventilation