Starfield Lighting Automation has been awarded a patent for a new type of daylighting control that is ultra efficient, easy to install, user friendly, and maintenance free. This new method readily integrates with other energy measures, automatically coordinates with other controls, and is equally applicable for single and multi-zone installations.
Daylighting, also known as daylight harvesting, is now an energy code requirement for both primary and secondary daylight zones. It is a conceptually simple process that works much like a thermostat but from its inception the industry has struggled to overcome the practical issues of sensor calibration, setpoint determination, interaction with users, and multi-zone operation.
The first issues, sensor calibration and setpoint determination, are inherently problematic because the light sensor that drives the daylighting is mounted on the ceiling. In order for daylighting to work reliably the ratio of reflected light at the ceiling and work surface light must be constant. Unfortunately, that is almost never the case. Reflected light reaching the sensor is dependent on room finishings, sun position, desk top clutter, and other conditions which are constantly changing so without frequent re-calibration operation quickly deteriorates.
The second issue of interaction with users, is equally daunting. The problem is that users and daylighting are both trying to control the same lights. Daylighting’s job is to maintain a fixed setpoint while occupants just want a level of light that meets their needs. One of these two is going to loose and with conventional daylighting it’s always the occupant.
And finally the third issue of multi-zone operation. Modern architecture is doing an impressive job of bringing daylight into buildings so there is more daylight to harvest. The conventional solution has been to use a single sensor with a manually determined proportional response for perimeter and internal zones. However, like sensor calibration, this only works as long as room and sun conditions remain constant which is effectively impossible.
The standard “solution” to these problems has been to use a high setpoint (150% of design light level) and suspend daylighting as soon as a user makes an adjustment. That solves the immediate problem but at the cost of eliminating most of the energy benefits.
Starfield’s patented adaptive setpoint daylighting resolves these problems through the simple act of re-purposing the mission of daylighting from saving energy to serving users. Surprisingly, giving users what they want is amazingly efficient. Field applications of this approach, along with companion measures like partial-on control and manual adjustment, have produced long-term, consistent savings in occupied space of 71% while allowing unlimited user adjustment, automatic interaction with AV and other systems, and elimination of both initial and ongoing manual adjustments.
LS230 Daylighting/Occupancy Combo Sensor
Daylighting Features and Benefits
- Automatic Calibration and Setpoint – No manual calibration or setpoint is required or available.
- Maintenance Free – Frequent re-calibration and setpoint refresh eliminates the maintenance while maintaining maximum energy savings.
- Location Tolerant – Adaptive Setpoint Daylighting is location tolerant so the conventional wisdom of separating occupancy and daylighting locations does not apply.
- Multi-Zone – Separate daylight sensors may be placed in multiple daylight zones without special calibration or setup.
- Bright or Dim Operation – Continuous operation and self-calibrating individual zones allow Adaptive Setpoint Daylighting to harvest energy in both dim and bright areas.
- Ultra Efficient – Continuous operation and full-room harvesting maximizing energy savings.
- Fade Guard ™ – Allows dimmable light sources to operate normally by suspending daylighting until fading and user adjustments are complete.
- Room Aware ™ – Assures that daylighting stays synchronized with other controls and the on/off state of the daylighting zone.