Low Velocity Displacement Ventilation
Ravenscroft specialises in providing low velocity displacement ventilation solutions to commercial and manufacturing premises.
Thermal displacement ventilation is based on cool air supply at low level and stratification of room air temperature and contaminants as a result of the natural buoyancy forces created by the heat sources. Traditionally the system has been designed as a dedicated outdoor air system.
Ravenscroft supports two alternative concepts used in a displacement ventilation system: horizontal low-velocity supply and floor-mounted diffusers. The extraction point of the exhaust air is located above the occupied zone – preferably close to ceiling level.
A displacement system is preferable for the following situations:
- the specific airflow rate per unit of floor area is high (as in lobbies, theatres, and conference rooms)
- high contaminant loads exist, as in industry and smoking areas
- the height of the space is more than 3 metres
Better Classroom Air Quality with Displacement Ventilation
Several international studies have found that indoor air quality in schools remains poor. This causes an increase in symptoms and illness, shortens attention span, while good air quality can enhance children’s concentration and also teachers’ productivity. The most common indoor climate problems are inadequate ventilation and thermal comfort.
In a recent article on indoor air quality in classrooms Panu Mustakallio and Risto Kosonen compared different air distribution methods and their effects on air quality in the classroom using a fullscale laboratory test to measure their performance. In their article, “Effect of Air Distribution Methods on Classroom Air Quality” originally published at Indoor Air 2011 conference, Mustakallio and Kosonen found that the average indoor air quality in the occupied zone was best with displacement ventilation, which also produced very good thermal conditions. For best results they recommend placing diffusers in all four corners of the classroom.
Displacement ventilation is also incredibly energy efficient, which makes it an excellent choice for ventilation in classrooms.