Photocell Sensors: Benefits of Daylight Harvesting

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Winter has arrived! With shorter days and longer nights, the limited daylight hours we do get never seem enough. Light affects the way we feel, and the right light levels can improve wellbeing, productivity and help us to complete tasks more effectively. At work, we need high levels of light to stay alert. The right lighting creates a brighter, cleaner-feeling workplace and can aid concentration and accuracy in work.


It is important that a workplace uses lighting or ‘lux’ levels that are appropriate to the room being used and the activities being performed. An office where Technical Drawings are created will need higher lux levels than an office canteen, for example. Different applications can require vastly different lux levels that are consistent throughout the day. At the same time, many workplaces want lighting that is energy efficient, not only in winter but year-round.

One way to meet these needs is through ‘daylight harvesting’. This is achieved by incorporating light sensors, also known as photocell sensors, into a lighting system. A photocell can detect levels of natural light and adjust the artificial light level accordingly. This means that lights can be switched on as natural light levels drop, and switched off again as natural light levels increase. More sophisticated photocell sensors can dim lights gradually when they detect increasing levels of natural light. Photocell sensors provide consistent lighting levels and only use as much light as necessary therefore reducing energy usage. Photocells can be wired or wireless, integral or plug-and-play. Which one you use depends on what you want out of the photocell and the application it is being used for.


Indoor Commercial Applications

If you want to light an office using a system where all lights use one photocell sensor, you can use a wired photocell. The photocell sensor acts as a switch and transfers signals to the lights connected to it based on daylight levels. You can programme the photocell to switch lights on or off or dim them, based on pre-determined natural light levels.

A wired daylight harvesting system offers a simple way to make the most of natural light and makes LED lighting even more efficient.  It is a great solution for basic indoor applications with energy saving benefits. However, if you want to programme lights to accurately reach a certain lux level and achieve maximum energy savings day and night, a smart lighting system with a wireless photocell sensor is the best option.

LG Panel Light with Multi-Sensor for daylight harvesting

Many lighting and electronics companies are seeing the potential of wireless daylight harvesting and have developed their own systems. Electronics giant LG has developed a wireless daylight harvesting system that is smart and user-friendly. Using a smartphone or tablet, you can programme a single photocell to wirelessly control a group of lights. Programming a photocell this way allows for more user control and accuracy. This is ideal in applications where a specific lux level is required, or where you want to achieve maximum energy savings.

For example, if you want to light a Reception area with a light level of 300 lux using LED downlights, you can programme the photocell to use daylight levels to determine how much more light the group of downlights will need to output to achieve the programmed lux level. Obviously, this output will vary throughout the day, and this is the key benefit of daylight harvesting; only the necessary amount of light is provided at any time, giving you year-round energy savings. A wireless daylight harvesting system also offers cheaper and easier installation, and less restriction in terms of where you install your photocell.


Outdoor Commercial Applications 

Another valuable use of daylight harvesting, especially in winter, is for outdoor lighting. As photocell sensors detect light levels and operate automatically, there is no need to set timers or turn lights on manually, which is reassuring as daylight hours change with the seasons.

An integral photocell sensor inside a lighting unit provides an easy way to save energy. The photocell will automatically activate a Flood Light with Photocell Sensor for daylight harvesting lighting unit at night, ensuring it is operational from dusk to dawn. This is ideal for outdoor lighting, where robust, low maintenance units are needed to simply illuminate outdoor areas automatically.

If, for example, you use wall packs with integral photocell sensors to light outdoor commercial and industrial areas, you will see increased energy savings with minimal setup and maintenance required. The only setup needed is the use of controls that allow you to select the natural light level that triggers lights to turn on or off.

Another simple daylight harvesting option is a plug-and-play photocell sensor that can be attached to a lighting unit, such as a flood light. As with the integral photocell sensor, the light will operate from dusk to dawn with simple setup required, making it ideal for outdoor lighting.

If you want to achieve optimum lighting levels with increased energy savings, then daylight harvesting is a simple and effective solution. For help and advice with setting up a lighting system using daylight harvesting, contact or call 01223 851505.