Technical article 2 min read Kyoto Mühendislik technical team
Stuffiness is the most frequent and the least understood complaint made about air conditioning systems. Even when the temperature is right, a space feels heavy if there is not enough fresh air.
Two components: people and floor area
The fresh air requirement is usually the sum of two items: the flow rate needed per person and the flow rate needed per unit of floor area. In a small but crowded meeting room the occupancy component dominates; in a large but rarely used store room, the area component does.
The type of space is decisive
The flow rates required for an office, a classroom, a restaurant, a sports hall and a hospital room differ considerably. In spaces with pollutant sources such as smoking, kitchens or laboratories, the exhaust flow rate is calculated separately as well.
The variable occupancy problem
Occupancy in meeting rooms, classrooms and restaurants changes substantially through the day. A system running at a constant flow rate wastes energy when the space is empty and falls short when it is full. The answer is automatic flow adjustment based on CO2 measurement.
The exhaust balance
The fresh air supplied must be able to leave. If the exhaust is insufficient, the space stays under positive pressure, doors are hard to open and the system cannot deliver the intended flow rate. Fresh air and exhaust are always calculated together.
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