Classroom Units

The unit is constructed with 50mm thick double skinned acoustically insulated panel. Each unit is complete with filters, fresh air/recirculation dampers, plate heat exchanger, LPHW heating coil, variable speed supply and extract fan, water pipework, 3 port valve, control panel, sensors, damper actuators and internally wired prior to testing.

Heating
The unit will start up in full recirculation mode and the valve to the heating coil fully open to preheat the classroom. On occupancy the system will revert to 100 % fresh and exhaust air with room temperature control via the 3 port valve.

CO2 Control
The fan speed will be controlled to regulate the C0² level below the stipulated 1500 parts per million level. In low occupancy, when the concentration is below 900 parts per million the fan speed will reduce to save energy.

Free Ambient Air Cooling
In winter with the high occupancy gains, there could be a cooling demand. The unit will control the room air temperature and lower the supply air off coil temperature to reduce the space temperature and provide free cooling. A low limit supply air temperature of 16 Deg C is set to prevent cold draughts being provided to the area.

Boost Ventilation
When there is a cooling demand from the space and no cooling is available from the outside air, the supply fan will shut down and the extract run in boost to increase the air change rate within the room. The boost mode will be activated on a predetermined return air set point temperature or a manual teacher operated push button.

Night Ambient Air Cooling
Heat which is stored in the fabric of the building during the daytime can be removed to reduce the temperate increase during the day. This function is carried out by using the lower night time ambient air and operating the unit to obtain the room set point during the night reducing the fabric gain.