A good design should take the characteristics of the space into consideration, such as how often that space is occupied in order to determine the approach, which could be one of the following:

1. Occupancy Mode
2. Vacancy Mode
3. Simple manual control using a wall switch
4. Manual switching with delayed auto off

K15 Occupancy

The basic premise is to have people manually turn the lights on. Often used for places which are not occupied for very long, where people come and go but not very frequently. Places that are infrequently used such as restrooms, elevator lobbies late at night, storage rooms, laundry rooms and so on.

Method of Control: Manual on, auto off.

Normally, sensors are used for motion, with infrared types being the most common, but basement parking is quite warm, and restroom is partitioned into stalls both of which diminishes the effectiveness of IR sensors unless the delay time is somewhat prolonged.

Solution: Lights can be turned on from any wall switch or by the use of sensors, after which a delay starts:

1. Wall switches may still be used to turn the lights off manually, the sensor will enter standby mode after 30 seconds.
2. If after the 30 second delay is up and there is no motion such as a hand being waved over the sensor then it means that no one is around, then the lights are turned off and the sensor enters standby mode.

In the past, sensors are quite commonly used, but having the sensor turn the lights on and off too frequently will only harm both the lamps and the relays controlling them, by shortening their lifespans. But there are times where the lights does not need to be turned only, but the sensors turn them on anyway which results in unnecessary wastage of energy. If this were to affect an infrequently used small room with only a few lamps, then it wouldn’t matter much, but if it were for a large area such as an elevator lobby, hallway or a restroom, then the lifespan of the lamps would be substantially be reduced. In addition, large capacity lamps such as gas discharge lamps, streetlights, where a long start up time is needed, then sensors are also inappropriate.

Application Features

1. Upon leaving, the occupant may manually turn the lights off; no need to wait for the delayed auto off to kick in.
2. At night, from the bedroom to the bathroom, the lights will turn on automatically, but the lights can be turned off at the bedside manually (K15 with the push button switch)
3. A long press on the push button connected to the K15 can have the lights remain on and temporarily ignore the sensor.

Vacancy Mode

Application Area: Public spaces that are occupied for prolonged periods such as reception rooms, offices, workshops, classrooms, libraries and labs.

This is a supplementary capability to help turn the lights off to avoid wasting energy for public spaces when they are not occupied.

Method of Control:

1. Lights can only be turned on manually
2. When the occupant leaves they can turn the lights off manually; but if they forget then the auto off kicks in.
3. If the delay off time is almost up, one needs only to wave at the sensor to extend the delay.
4. The lights can still be forcibly turned off in instances such as when doing a presentation or when taking a nap.

Mode:

1. The lights need to be turned on manually from the switch.
2. When the occupant leaves, they should turn the lights off manually, but if they forget, the controller will turn the lights off automatically. The purpose of vacancy mode is for when the occupant leaves and the room becomes vacant.

Application Features

1. If someone is just passing through and has no actual intention to turn the lights on, then it won’t turn on.
2. If the lights need to be turned off then it can be, such as when making a presentation or taking a nap.

K20 Delay Switch

Area of Use: Hallway or stairwells; their primary use is for controlling the lights in long passageways or corridors. Push button switches should be installed along the length of the passageway for the convenient operation by the occupant.

Equipment: Multiple push button wall switches are installed along the length of the passage and connected in parallel, this would allow the lights to be turned on from anywhere and turned off from anywhere; anywhere a switch is installed. If the user forgets, the lights will still turn off automatically.

Energy saving control for street lighting, parking lots, daylit hallways and building facade lights.

Public outdoor lights are on for long periods of time, they cover large areas and are very bright, and thus they often enormous amounts of power. But since they are in the public, they are very visible and noticeable, oftentimes they are already on even when there’s still light, which gives the public the impression that there is no effort to save on energy, and management is ineffective. Hence, this is a focal point for energy management.

Most traditional approaches to energy saving for outdoor lighting is by making use of automatic control to turn the lights on or off, which works in conjunction with light and dark to automatically turn the lights either on or off, but this approach has several shortcomings.

1. The lights should come on when it becomes dark, but it doesn’t mean that the lights should remain on up until it is light before turning off. The best approach is to have a different time schedule for each light post depending on its location to turn the lights on at a designated time and to turn it off early. But if automatic control is dependent entirely on a daylight sensor, then the lights would only turn off when it is light. The correct approach would be to turn on at a certain time depending on the venue, and turn off at a designated time, it should not be that the  lights only turn off when it is light. This is not something that can be easily done using a simple daylight sensor. But if a timer is used, it cannot adjust its time to match seasonal changes, and can either turn the lights on too early or too late.
2. It can often be seen in sidewalks, that even though it is already daylight, the street lights are still on, this is often caused by the daylight sensors when their calibration skews over time. Or it could also be caused by having its receptors obscured by trees, nearby buildings or plant overgrowths, which causes it to malfunction. This results in much wasted energy and also in reducing the lamp lifespan, constantly maintaining the street lights to ensure that they are operating in peak condition is labor intensive and costly for both its labor and materials.
3. The sensitivity of daylight sensors can vary widely, which can be seen in some areas wherein a segment of lights being turned on, while another segment in the same vicinity remaining off. This appears inconsistent and gives a bad impression to the public and reduces the quality of service.
4. Daylight sensors do not gauge dimness in the same manner as people do, which causes the daylight sensors to turn on the lights even though people still think it is still light. This of course results in unnecessarily wasted energy. The administrator is unable to make adjustments to and is entirely at the mercy of the daylight sensor in deciding when to turn on the lights.
5. The location in which to install the daylight sensor is very finicky, if there are objects or structures close by that could potentially block its receptors, then it could cause it to make faulty decisions. If the daylight sensor is in an ideal location, it could be far from the switch that controls the lights, which means that additional wiring need to be laid out from the sensor to the switch, which of course means additional labor and material costs, not to mention the difficulty in the actual construction job.

Improved Approach

1. Make use of the K40 monthly adjustable controller, each month would have its own turn on time, which solves the problem of indeterminate turn on time, and won’t turn on too early nor too late. Since there is no longer the need to install a daylight sensor, it also eliminates the problems associated with the laying of the conduit wiring. Thus, costs are reduced. Turn on times are not determinate and all lights could now be synchronized.
2. Depending on the place and purpose, it is not always necessary to have the lights all turn off at the same time, as for example, the circuit could be arrange so that the light posts alternate, or grouping could be made into primary and secondary circuits, and each group could have their own turn off time. Applications for this such as for billboards, exterior building wall wash lighting, pathways, streetlights, parking lots.
3. Late at night, when few people are about, such as in parking lots, one could make use of the LT3000 with motion sensors, so that instead of leaving the lights on all night, they will only turn on when there are people about. Which also helps to reduce wasted energy.

In Conclusion

Daylight sensors are simple in principle, and they are inexpensive. But the difficulties that they cause results in much energy wasted and also in reduced lamp lifespan. With the use of the K40 and the K90 in combination with push button wall switches can be used to adapt to the routine and also helps to reduce energy use at the same time. In addition, they can be adjusted to the venue and seasonal changes, with the ability to change the turn on and turn off times which allows the administrator to be in control at all times.

Some schools have computer rooms that are open for the students to use, after peak hours most of the students have left, and so most of the time the room is unoccupied, but the lights and air conditioning all remain on, which results in much energy wasted.

Computers rooms are divided into multiple sections and each section would have their own lighting and air conditioning energy saving switch.

1. The student can manually operate the buttons to turn on the lighting and power outlets in a given section.
2. The air conditioning would be restricted: only when a certain temperature threshold is reached would the air conditioning be allowed from being turned on.
3. Once the students have left, there will be a period of time where the room is being observed by the sensor to make sure that everyone has truly left, then it will automatically turn off the lights and the air conditioning.

Most small rooms such as pantries, copy rooms, smoking rooms, restrooms have people coming and going frequently but staying only for a very short time; they only a single circuit and the K15 or K24 smart sensor switches would be suitable for delayed auto off control.

1. The K15 or K24 is recommended for such applications.
2. Operate using the occupancy mode; lights will turn on when people come, lights turn off when people leave.
3. Since these spaces have small areas, the lighting load is also low; hence, the internal relays of the K15 or K24 can be directly connected to the lighting without reducing the lifespan of the relays.
4. It is recommended that the delay time be set to about 10 minutes or so.
5. The sensor should not be installed near windows or ventilation openings as to reduce the false triggering.