Daylight Harvesting–The New Step to Energy Saving

Lights affect the way we feel. It’s obvious that the natural light is a source of illumination. With ever-increasing demands for energy savings on one side and better recognizing the benefits of natural light for our health on the other side, more businesses are turning to daylight harvesting as means to conserve energy and bring sunlight back into their buildings and workspaces.

Daylight Harvesting is one of the most advanced techniques used in sustainable lighting designs for contemporary buildings. It automatically dims or adjusts the brightness of light in response to the amount of natural light available in a space. Utilizing natural daylight coming through the windows or skylights minimizes the amount of energy used in artificial lighting.

How Does Daylight Harvesting Work?

The daylight harvesting system employs light sensors, also known as photocell sensors, to detect the prevailing light level in the environment. It then sends the intensity of light received to a controller, which is connected to the lighting control system. The control system in turn adjusts the electric lights automatically according to the measured light level.

Types of Daylight Harvesting Systems

There are two control modes for daylight harvesting; open-loop and closed-loop control systems.

In an open-loop control system, the photosensor measures only the intensity of natural light, thereby adjusting the intensity level of the artificial light to support, offset, or balance the contribution of natural light during the day.

Open-loop sensors are typically installed outside the building or near a window or facing towards the source of daylight. Since there is no feedback from the electric lighting, this is considered an open-loop.

In a closed-loop control system, the photosensor detects the total amount of light intensity, from both natural and electric sources in the environment. And, based on the detected light intensity level, it adjusts the intensity level of the artificial light to maintain pre-set ambient light intensities.

Closed-loop sensors are typically installed indoors, facing away from the daylight source.

Since the photosensor measures the artificial lighting system’s output, it provides feedback to controller and make further adjustments to maintain the pre-set value creating a closed loop.

Daylight harvesting- Two control modes

Why should you use it?

Energy Savings

It increases energy savings by dimming or turning Off lights based on the natural daylight entering the space.

Provides Comfort and Convenience

It helps to maintain proper light intensity in a space by continuously and automatically adjusting lights.

Healthier Working Conditions

Providing right amounts of light to employees helps in maintaining proper circadian rhythms that are crucial to good health and adequate sleep besides preventing seasonal affective disorders. Letting in natural light to workplaces provide better concentration, creates a positive mood, and drive healthier employee life.

Meet Codes and Standards

Daylight harvesting helps meet Title 24 and ASHRAE 90.1 requirements using continuous dimming, task tuning, space control, and automatic/manual ON/OFF controls. It achieves the mandatory compliance needs set for building construction.

Contributing to the cause, WiSilica’s sensor devices like WXD2CPLR and WXD2CPLC helps in reducing energy consumption in enterprises and enables in-house lighting products to be smart and compliant to the energy efficiency standards.

ARIXA, the location-aware IoT platform, powers LUMOS – our Intelligent Wireless Control Solutions to enhance user experience, increase lighting comforts, and improve energy efficiency. WiSilica, also offers control devices to enhance the better experience of daylight harvesting.

WiSilica will continue to delve into daylight harvesting to come up with more energy savings techniques in future posts. Visit our website to learn more about our smart lighting products.