Tag Archives: LED Lighting

Role of LEDs in Horticulture

While LEDs have revolutionized indoor and exterior lighting methods, they have been revolutionizing operations involving indoor grow facilities. This is mainly because LEDs are highly flexible in their spectral output, while their efficiency is very high. That means they emit much lower heat.

A new standard from ASABE specifies the performance of LED lighting products for horticulture applications. The standard spells out the test methods to measure the optical radiation from LEDs in the range 280-800 nm. Note the visible spectrum covers about 390-700 nm.

According to the Standards and Technical director of ASABE, Scott Cedarquist, in horticultural applications, LED lighting has generated very high levels of interest in their projects in the last 20 years. Therefore, horticultural lighting makes use of several terminologies that are primarily focused on plants. Two of them are PPFD or Photosynthetic Photon Flus Density and PPF or Photosynthetic Photon Flux.

While PPFD measures the number of active photons falling on a surface per unit area per unit of time, PPF is the number of photons created by a lighting system per second.

Horticultural lighting primarily focuses on delivering photons that initiate photosynthesis and other processes in plants. These spur plant development as they excite electrons. Horticultural applications use LED products that are different from those used for general illumination. The difference is primarily that the former has a wider spectral output typical for horticultural applications. This is necessary as different plants respond differently to various wavelengths.

According to academic and industry research, each type of plant has a specific light recipe that helps the plant to yield higher growth in the shortest period. The recipe holds the variation in optical spectra for optimizing the overall growth of the plant, thereby improving desirable plant characteristics. For instance, increasing the potency of cannabis or the flavor of vegetables.

The light output from LEDs has another characteristic. Not only do LEDs provide a precise output spectrum, but this spectrum can also be tuned to optimize the spectrum for different plants and the phases of their life.

LED lighting products are primarily used in horticulture as vertical farms. This is due to the far lower heat output from LEDs as compared to that from other light sources. This allows the LEDs to be interspersed very close to the plants without damaging them. Therefore, facility managers are able to maximize the use of available space. This has made vertical farming very popular in urban areas. Horticulturists are making use of abandoned buildings which they are converting to grow food, thereby making new products available at cheaper rates.

The high efficiency of LEDs also helps considerably in energy savings. However, grow facility managers are more interested in the yield of the crop, and use of LEDs for high-value crops such as cannabis offer revenue increase from higher yield and shorter life cycle, rather than from energy savings. Similarly, more traditional crops such as flowers and leafy vegetables also use LED lighting not for energy savings, but rather for the ability to produce more crops in a shorter period.

Intelligence in LED Lighting

Apart from illuminating dark spaces there is much more to LED lighting than otherwise thought of. LEDs can be connected in an intelligent network with a low-voltage IP-based infrastructure, and they become a part of a powerful network of systems. Such a system can cooperatively collect, analyze, manage, control, and respond to specific objectives based on real-time sensor feedback.

The building lit up by these LEDs now behaves as a smart building, offering better operational performance. It responds dynamically to operating issues related to power consumption and cost, increasing efficiency and efficacy. Moreover, such integrated intelligent lighting works smoothly with the other systems in the building.

The major issue confronting LED networks is decoupling from the relatively universal approach of a centralized lighting control. It makes more sense to change over to a solution that caters to the specific requirements of smaller segments across a large area within the building. Moreover, as lighting is a part of the intelligent network, it can integrate with and respond to other components on the network. Such an approach works very well for commercial office buildings, warehouses, healthcare facilities, manufacturing and industrial facilities, and other similar large or multipurpose areas, where a centralized approach will be inefficient and ineffective.

As an example, buildings are very commonly controlled through automated heating, ventilation, and air conditioning−also called the HVAC system. The HVAC has the task of monitoring and adjusting the temperature to make the building suitable for human comfort and machine performance. Moreover, it does this at optimal efficiency and cost. An intelligent LED lighting network connected to the system would allow lighting to synchronize into the same set of objectives. Now, the lighting couples actively and responds to environmental climate control.

This gives the lighting network the intelligence to increase the ability of users to adjust the light within the building to increase human productivity, concentration, positive mood, and well-being. Moreover, by adjusting light synchronized to the natural circadian cycle and adjusting the amount of light required depending on the amount of sunlight filtering through external windows, additional potential advantages can be achieved.

All intelligent LED lighting networks need power, and the key technology behind this is Power over Ethernet (PoE). This brings the equipment and low-voltage cabling necessary to connect the assets of Internet of Things (IoT) to LED fixtures. The success of IP-based infrastructure platforms makes PoE simple and available. Therefore, by using PoE as the arteries of the LED lighting systems for power and control, lighting also becomes a part of the building’s IoT asset.

PoE provides an infrastructure that is less expensive compared to copper cables, while offering a single layer for transferring power and data. Typically, the PoE system architecture consists of the PoE gateways, LED light fixtures, LED lights, smart drivers for LEDs, cable harnesses, sensors, wireless switches and dimmers. In general, PoE gateways are configured to use any one source from unregulated 48 VDC, constant voltage 24 VDC/48 VDC, or constant current.

There may be wireless PoE gateways as well, conforming to IEEE 802 standards. Usually, they run at standard frequencies such as 902 MHz in the North Americas, and at 868 MHz in Europe.

Making City Streetlights Smart with DALI

Big cities are changing over to LED lights for illumination of their streets. They find this to be a smart solution in terms of cost-reduction and efficiency. STMicroelectronics is taking an important next step by adopting LEDs for street illumination. They are doing this in conjunction with smart power supplies that turn the LED street lamps into intelligent devices. For example, the streetlamps reduce their brightness as the sun rises while gradually increasing their brightness with failing daylight. They also communicate with the smart grid in their effort to reduce the power consumption.

To avoid losses and manage electricity consumption smartly, STMicroelectronics is using LEDs that are dimmable and connected to smart grid systems. Microcontrollers drive the LEDs, and the system avoids the power losses commonly associated with non-optimized management of power such as with the use of incandescent bulbs and other forms of commonly utilized lights.

STMicroelectronics present their new solution in the form of a demo board based on STLUX385A, a digital power controller. Using a proprietary power conversion protocol, the controller drives a row of LEDs for the smart-lighting applications. DALI forms the core of the new STsystem for smartly driving the LED row.

DALI or the Digital Addressable Lighting Interface, is also standardized as IEC 929, and is a new interface for controlling lighting as defined by the lighting industry. The DCM or the DALI Communication Module generally implements DALI protocol. DCM is a serial communication circuit designed especially for controllable electronic ballasts – the device or circuit that provides the required starting voltage and operating current for the LEDs.

LEDs are different from CFLs and incandescent bulbs. LEDs require a supply of constant current. They start emitting light as soon as their forward electric threshold voltage is reached. Effectiveness of the illumination provided by a string of LEDs depends on the product of the current and the voltage applied to the string, and this must be stable in time.

HF fluorescent ballasts use the DSI protocol, and DALI is a step further. Unlike DSI and other 1-10V devices that address and control devices in a group, DALI can address each device separately on a segment of a data cable. Therefore, for achieving similar control functionality, DALI requires a simpler wiring topology as compared with DSI or 1-10V devices.

Devices that DALI can control include, apart from LEDs, wall switches, gateways to other protocols, motion detectors, PE cells, low-voltage transformers and HF ballasts for Fluorescent tubes. A single DALI network can address up to 64 DALI devices. When sites require more than 64, multiple separate DALI networks are established, each limited to 64 devices. DALI gateways then link these separate networks together, forming a data backbone running a high-level protocol, typically, DyNet from Dynalite.

Implementation of DALI facilitates equipment from different vendors to the integrated easily. This reduces the installation costs drastically, offering a finer granularity of control for a given price. However, DALI still does not totally remove the need for a data cable connect to fixtures. It also does not reduce the time required for programming and commissioning the lights. Additionally, unless extra equipment is used, DALI does not help to save the maximum possible amount of energy.

LED High Bay Lighting Produces 23650 Lumens

Hubbell Lighting, the pioneer in lighting innovation, has recently launched LUNABAY. This is an LED high bay lighting for the company’s high output categories, one that maintains an optimum efficiency of 95 Lumens per watt. The LUNABAY range can generate as high as 23,650 Lumens. Three levels of lighting are available in this range: 23,650 Lumens, 18,000 Lumens and 12,300 Lumens. Another aspect is the lights offer a CRI of 68 and is tagged with Uplight components. The LED high bay lighting ranges from 130W to 260W of total the system wattage. The lighting functions in an ambient environment within a temperature range of -40°C to +40°C. The lighting has an assured life of 50,000 hours at L70.

Lighting public places require specific features. It must cover the entire area uniformly as well as it has to present a pleasant ambiance. At the same time, it must also be safe and affordable. LUNABAY from Hubbell Lighting provides efficient lighting with a low-glare light and high level of durability. The places where this LED High bay lighting could be utilized are quite vast. They include multipurpose rooms in educational institutions, retail stores, gyms, light industrial facilities and all other places where it is essential to light the interior locations in an attractive and effective manner. LUNABAY provides lighting that cannot be matched for efficiency and durability by any other product currently available in the market.

The most important aspect of LUNABAY is its low glare feature of the LED light it produces. This feature is specifically patented and it remains an exclusive domain for Hubbell. Typically, conventional downlights in large areas generate glare and create a cave-like effect. The special optical system used in LUNBAY totally removes this discrepancy. It offers smoothly and evenly distributed light, which is consistent, has a low glare and a high CRI.

Another aspect to be noted is that the two refractors, 22” crystal clear and 23” aluminum possess Uplight components of 10% and 20% respectively. The LUNABAY lighting offers five color temperatures. The chimney part at the top can have a choice of seven colors matching the interiors. Apart from custom colors, users may select colors from white, red, black, forest green, dark bronze and platinum silver. LUNBAY offers multiple options, which includes control over on/off, fusing, wire guard, no light or 50% light output – leading to additional saving of energy. In emergency, LUNABAY is also compatible with 250VA Light Gear Inverters.

Hubbell Lighting is one the leading and largest producers of lighting fixtures in the USA. Their range covers the complete category of indoor and outdoor lighting products catering to residential needs, commercial lighting, institutional requirements and industrial markets. One of the special features of Hubbell Lighting is that the company has been consistent in developing new products in lighting, resulting in energy savings while at the same time remaining affordable to customers. The LUNABAY LED High bay Lighting is their latest product and is the only one to produce up to 23,650 Lumens. This new LED lighting is sure to make a significant positive impact on the market.