Mechanical ventilation system performance involves the provision of adequate amounts of outdoor air, uniform distribution of ventilation air within the occupied space, and the maintenance of thermal comfort. Standardized measurement techniques exist to evaluate thermal comfort and air exchange rates in mechanically ventilated buildings; field techniques to evaluate air distribution or ventilation effectiveness are still being developed. This paper presents field measurements of air exchange rates and ventilation effectiveness in an officepibra-y building in Washington, DC.
A microprocessor system is being developed for occupancy related ventilation control of mechanical ventilation in Brunel University Library. The objective is to reduce space heating costs by decreasing the input of (cold) fresh air to the building below existing (heating season) levels, when the number of occupants in the building is sufficiently small to allow this. The occupancy levels can be measured in terms of CO2 level in the exhaust duct. The microprocessor control system is operational when linked to a CO2 monitor.
Describes tests in Exeter University library of method of determining ventilation rate by measuring the amount that the atmospheric carbon dioxide concentration in an occupied space is raised above the outside ambient level. Compares rate obtained with that expected from the fan rating. Demonstrates that in addition to the ventilation rate, the average rate of production of carbon dioxide produced by the occupants could in principle have been estimated from the data.
Login