Central facade control is used to protect room users in a building against glare.
The function also includes thermal protection for the rooms. The measured global radiation is analyzed together with the present HVAC values in the room to prevent the room from overheating with the help of facade products.
|
| |||
WS | Weather station |
| AS | Room automation station |
|
|
| CAS | Central automation station for facade control |
Figure: Plant diagram for façade control automation station
Anti-glare protection and solar position
tracking
The present solar angle can be calculated based on a building's geographical position as well as date and time and use a solar sensor to evaluate solar radiation. On facade segments (i.e. windows with the same conditions with regard to anti-glare, thermal solar radiation, and brightness), this information can be used to deploy blinds or lighting control to a defined position to prevent any direct solar radiation from penetrating the room.
Calculation of the solar angle as per the position of the building
The position data for the facade are required to determine the solar radiation angle on the facade. This permits deployment of blinds to the optimum position for anti-glare protection. Each facade possesses the following parameters for determining the position.
Description | Name | Default value |
|---|---|---|
North latitude - 90 ... 90 | Latit | 47.17 |
East longitude - 180 ... 180 | Lngit | 8.52 |
Facade azimuth angle - 360 ... 360 | FcdAzmth | 180 (south) |
Facade angle of inclination - 90 ... 90 | FcdIncl | 90 (vertical) |
Measurement of solar radiation
Solar radiation is determined using a brightness sensor. The following brightness sensors can be read on DXR2 for anti-glare protection:
Sensor | Inputs | Information is used for |
|---|---|---|
Outdoor brightness north | 0… 10 V | Application: Anti-glare protection |
Outdoor brightness east | 0… 10 V | Application: Anti-glare protection |
Outdoor brightness south | 0… 10 V | Application: Anti-glare protection |
Outdoor brightness west | 0… 10 V | Application: Anti-glare protection |
CAUTION!
Measurements for anti-glare protection are typically made in three cardinal points since most commonly available brightness sensors have a horizontal coverage of 90°. The following applies in general depending on the position of the building:
Sensor direction | General position of the building |
|---|---|
East, south, west | North of the Equator |
East, north, west | South of the Equator |
A more detailed consideration of the sensor orientation is required if the project is located near the arctic circles. On common Internet search machines, a search for "sun's course" provides useful information on a simpler definition of sensor orientation.