LED Lighting 101

Philips Gardco statement on LED

Philips Gardco now incorporates the use of LEDs as a source in a number of luminaires. Working with LEDs presents challenges. Some of those challenges are similar to other, more traditional sources and some are unique to working with LEDs. LEDs perform well in cold temperatures; in fact thrive in cold temperatures, making them suitable for many climates that present obstacles for other sources. LEDs generate significant heat from the source, despite the small size, which makes thermal management a must. Clustering LEDs is common and necessary which increases the thermal challenge.

Philips Gardco has engineered its LED products with thermal management as the top priority. As the wattage grows, and therefore the useful light increases, the heat increases as well and the thermal management becomes even more important. For owners to realize return on investment, LEDs must have a high life expectancy. Gardco takes this responsibility very seriously. We strive to provide solutions that offer viable lighting instruments, keeping performance and aesthetics in mind. We want our LED products to provide a sustainable and environmentally responsible solution that also meet the real world return on investment needs of owners.

What is an LED?

Light-emitting diode (LED) is an electroluminescence semiconductor that emits narrow-spectrum light when conducting current in the forward direction of the p-n junction. Like normal diodes, the electrons (- charged particles) move in one direction. But with certain types of semiconductors the electron meets the electron hole, it falls into a lower energy level and release the energy in the form of photons (light).

What is an LED Driver?

Phillips Gardco uses LEDs that require a DC power source that regulates the current independent from the voltage input. For HID Luminaries we use a ballast to regulate the voltage and current but LEDs need a Driver to regulate the power. An LED Driver maintains a contain (?) current through the diode.

How important is thermal management?

Philips Gardco has engineered its LED products with thermal management as the top priority. As the wattage grows, and therefore the useful light increases, the heat increases as well and the thermal management becomes even more important. For owners to realize return on investment, LEDs must have high life expectancy. Gardco takes this responsibility very seriously. We strive to provide solutions that offer viable lighting instruments, keeping performance and aesthetics in mind. We want our LED products to provide a sustainable and environmentally responsible solution that also meet the real world return on investment needs of owners.

What is the life span of an LED?

The life span of an LED is directly proportionate to the thermal management of the die’s junction region. Most LED manufactures state that the LED will last 50,000 hours with 70% lumen maintenance if the junction temperature stays at a 85°C. Philips Gardco maintains an 85° junction temperature even if the ambient temperature is 40°C (104°F). This means our product will stay brighter, longer, even in the most extreme environments.

How do Philips Gardco products manage heat? 

Philips Gardco uses a passive cooling method on all of its LED products. Passive cooling uses the surface area of a heat sinks and air convection to cool the LED. By avoiding fans and mechanical methods of cooling the LED, we remove the reliance of a part that could fail over the lifetime of the product. Also Philips Gardco uses cross cuts on the Radiant heat sink to maximize air flow in all directions.

What is the overall energy consumption of a Gardco LED system? 

The system power takes in account the driver and LED Array of the product this includes all of the energy loses from the driver component and heat dissipation. Also, the LED voltages fluctuate because of the manufacturing process of the die’s forward voltage and temperature. This may increase or decrease the energy consumption by +/-8%. Below are some reading of Gardco Radiant and 121 LED Sconce.

The cooler the ambient temperature; the longer and brighter the LED will last. Depending on the region of the country where the product is located will directly affect the products performance. Philips Gardco designed the thermal management to keep the LED with in spec even in the most extreme hot summer nights (40°C). With the average night time temperatures being a cool 15°C expect a long life with high performance.

How can we compare LEDs to Traditional Sources?

How does LED Photometry compare to HID?

LED luminaires are tested using absolute photometry versus relative photometry, which is the standard for all other light sources. Therefore, LED lumen ratings cannot be treated equally to HID luminaire lumen ratings. A better approach is to compare the area of coverage to a given minimum illuminance level; utilizing isocurve templates for example.

How do LED luminaire wattages compare to HID luminaires?

The following table provides a rough correlation between the Gardco LED systems and a PSMH luminaire.

What happens at “End of Life” for a LED Product?

LEDs do not abruptly burn-out like traditional sources; instead they dim to the point when light can’t be seen. This dimming we take many years after the LED has reached the 70% Lumen Maintenance point. Philips Gardco has designed our LED products for a module LED array to be replaced in the future.

What is an appropriate lumen deprecation factor for an LED Product?

Gardco has adopted a 0.85 lumen depreciation factor when running calculations. This equates to the mid-point or mean lumen output based on the L70 lamp life ratings. With HID lamps, the mean lumen rating is based on 40% of rated life, so this approach towards LED is even more conservative.