This mode is intended for a more complex mixed mode system where openings are controlled from a single zone's dry bulb temperature, and the apertures are closed as this zone temperature exceeds a cut-off value, so mechanical cooling can be introduced through Internal Conditions. In addition another zone is specified to act as an override control so that if it has a dry bulb temperature greater than the cut-off value, then the aperture will close. This mode requires the following parameters.
Parameter |
Description |
Zone |
The zone name whose dry bulb temperature will control the aperture. |
Override zone |
The name of the zone whose dry bulb temperature is to be used as an additional cut-off control. |
Lower limit |
The aperture will be closed if the controlling zone dry bulb temperature is below this value. |
Upper limit |
The aperture will be fully open if the controlling zone dry bulb temperature is above this value. |
Cut-off |
The aperture will start to close as the zone temperature rises above this value. The aperture will be fully closed at one degree above this value. |
Upper wind speed |
The aperture will start to close when the wind speed exceeds this value. The aperture will be fully closed at 0.5m/s above this value. |
For example, the automatic control function odwom could have the parameters set as following:
Zone: East Office
Override Zone: West Office
Lower limit: 22
Upper limit: 24
Cut-off: 25
Upper Wind Speed: 5.0
This would define the following strategy for aperture opening. As the dry bulb temperature in 'East Office' rose above 22C the aperture would start to open. The aperture would be fully open at 24C and remain fully open until 25C when it would start to close. At 26C and above the aperture would be closed. The aperture will also close if, at any time, the outside temperature is greater than the inside temperature. The aperture starts to close when the two temperatures are equal and will be fully closed when the outside temperature is one full degree above inside. The wind speed will also start to shut the aperture as it increases above 5m/s and be fully closed at 5.5m/s. Finally, as the dry bulb temperature in 'West Office' rises above 25C the aperture will start to close. When the temperature of 'West Office' is above 26C the aperture will be shut. For a full description of how final aperture opening values are calculated please see the section: Aperture Type Functions.