Efficiency of LED Luminaires Significantly Increased

United States

WE-EF develops, manufactures, and markets high quality lighting for outdoor use. The focus is on innovative optical systems, good heat management, and high IP ratings. Its aim is to design lighting that is extremely durable and efficient despite harsh climatic conditions. This is a particular challenge in the case of the LEDs that WE-EF uses in newer street and area lighting luminaires.


Situation
Case Study: WE-EF

WE-EF is an exterior lighting specialist that develops, manufactures, and markets high-quality luminaires for outdoor use with a focus on innovative optical systems, good thermal management, and high IP ratings. Its aim is to design lighting that demonstrates extreme longevity and efficiency even in the face of adverse climatic conditions. This poses a particular challenge in the case of the LEDs that WE-EF uses in its newer post-mounted street and area lighting luminaires.

Challenge

For its VFL500 LED series, WE-EF uses RFC® Reflection Free Contour technology to achieve the highest possible optical efficiency. The conventional flat-glass cover is replaced by a UV-stabilized, clear, contoured acrylic panel that follows the shape of the lens. The RFC® technology ensures that light from the lens always hits the inside of the cover at a 90-degree angle of incidence. This reduces reflection losses and increases lighting efficiency by up to 5 percent. To achieve this level of efficiency, pressure fluctuations in the housing must be avoided in order to prevent a vacuum. Caused by the enormous temperature differences between the LEDs, which heat up during operation, and the cooler ambient air, such pressure fluctuations would cause the acrylic cover to deform and so alter the illumination characteristics of the emitted light.

Solution
Casy Study: WE-EF pressure curve

Temperatures inside a VFL500 luminaire can easily reach +65°C, but can drop to +15°C in the space of 10 minutes during a storm. In a vented housing, this causes no pressures differential because the vent allows the pressure to equalize easily. Without a vent, the housing is subjected to a pressure of -140 mbar, which causes dirt and moisture to be sucked in via the seal.

This undesired effect can be prevented using a vent to equalize the pressure, thereby ensuring the acrylic cover retains its original shape. To achieve the desired efficiency, WE-EF integrates Gore PolyVents M12 x 1.5 HA (PMF100391) in all of its VFL500 series LED street and area lighting luminaires. Back while the product was still in development, WE-EF decided to opt for the screw-in vent with high-airflow membrane. This meant the vent could be incorporated into the luminaire housing in such a way that it remained invisible from the outside and did not impact the overall design. With the built-in vent, pressure fluctuations are equalized reliably and less strain is put on the seals, ensuring the sensitive interior electronics are protected against moisture penetration for decades.

 

"Just like our luminaires, what characterizes Gore vents is their long service Life," explains General Sales Manager Thomas Müller. "We’ve not had a single product failure so far and we’re very satisfied with this particular solution." By fitting Gore vents, WE-EF is able not only to greatly increase the longevity of the entire lighting system, but also to guarantee the reliability of the newly employed RFC® technology and thus assure the efficiency of the luminaire. This added value is a convincing selling point for the exterior lighting specialist’s customers. Effective protection of the components inside the housing is a must if the luminaires are to work without failing for more than 20 years. "We ensure our products achieve an IP66 rating, which gives our electronics and LEDs a rated life of 60,000 hours," says Thomas Müller. “The only way to do this is with a high-performance venting solution and reliable seals.”

Case Study: WE-EF

GORE Protective Vents are available in many different sizes and designs and can be easily integrated into new or existing design structures. With ist high-airflow membrane, the screw-in PolyVent M12 x 1.5 HA is the ideal venting solution for WE-EF's VFL500 luminaire series.