Lighting

All About Finishing

Finishing-Spectrum.png

GrowFlux's FluxScale series fixtures are capable of delivering broad spectrum PAR containing a very high proportion of blue light, which is used to deliver Finishing light treatments in the 12-96 hours prior to harvest. Finishing Light Formulas boost terpene and resin content in crops by triggering protective mechanisms within the flowers. 

Unlike other LED fixtures on the market, FluxScale is capable of delivering this spectrum at full intensity exceeding 800 μmol/m2/s, allowing a finishing treatment without stunting plant growth. Other LED fixtures only deliver a similar spectrum at low intensity, resulting in diminished growth and shade avoidance responses. 

The GrowFlux Cloud Platform includes several pre-configured Finishing Light Formulas containing spectrum settings and lighting schedules shown to enhance terpene and resin content. Check out our whitepaper for more information:

FluxScale Finishing Spectrum

Lighting controls: Three things to consider when selecting a horticultural lighting solution

  GrowFlux Wireless Access Point

GrowFlux Wireless Access Point

When planning a large scale Controlled Environment Agriculture (CEA) facility such as a hybrid lit greenhouse or indoor cultivation space, network resilience, network set up time, and installation cost are important factors to consider in selecting a horticultural lighting solution. Some lighting solutions on the market require zone controllers and data cables, which adds labor and cost to the installation process. Most wireless lighting control solutions require a multi step network setup process for each fixture, which adds up to a significant amount of time for facilities requiring hundreds or thousands of fixtures. 

For wireless control solutions, network resilience is an important factor to consider for large scale facilities. Unreliable lighting network connectivity can grind a large facility to a halt, sucking up time and resources to troubleshoot network issues all while the lighting solution is not performing as designed.

  AetherMesh wireless module used in GrowFlux lighting and sensing products

AetherMesh wireless module used in GrowFlux lighting and sensing products

Only GrowFlux offers AetherMesh wireless controls on all of its products. AetherMesh was designed specifically for large scale CEA facilities and solves the issues discussed above:

Network resilience:

  • AetherMesh communicates on Sub 1-GHz frequencies and utilizes a high efficiency, high gain antenna, ensuring that wireless signals easily penetrate through dense buildings, multiple walls, concrete, and warehouses containing dense arrays of shelving.

  • Line of sight range of 1+ mile (1.6+ km) is possible between AetherMesh devices; indoor range through walls is typically upwards of 500ft (150+ m).

  • AetherMesh wireless mesh links self heal. If a device has trouble routing a message through one route, the mesh automatically finds another path through which to route messages. All network nodes maintain multiple network paths through which to route messages, choosing the most power and traffic efficient route in real time.

  • AetherMesh splits the 902-928 MHz band into 50 channels; the network automatically channel hops communication across these channels to avoid interference.

  • When we communicate lighting settings to a zone of fixtures, we send up to 90 days of scheduled control. This ensures that fixtures know exactly what they should be doing in the event of communication failure. Fixtures immediately get back to the correct scheduled control after any power failures.

Network setup time:

  • GrowFlux products incorporating AetherMesh wireless control set up rapidly out of the box - simply power on the device for the first time within 10 feet of your Access Point, and the device will securely join and remember the network within 30 seconds. AetherMesh network setup does not involve passwords, codes, IP address, or any other complicated network setup steps.

  • Connecting hundreds or thousands of fixtures happens as fast as the units are unpacked. Unpacking and initial power on occurs near an Access Point prior to hanging the fixture in the grow space.

  • Zone definition is entirely software based with our browser based interface - zones are not defined through network settings.

Installation cost:

  • One Access Point can support networks upwards of 1000 devices, significantly reducing cost

  • Zone definition is entirely software based, so hardware zone controllers are eliminated.

  • Every fixture on the network operates as a full power wireless mesh node (battery powered sensors perform limited extension of the mesh network to conserve battery life). This means repeaters and additional gateways are not required for large networks.

  • Since GrowFlux products are fully wireless, the installation labor and cost associated with data cables and controllers is eliminated.

Coefficient of Utilization (CU) explained

Photosynthetic Photon Flux Density (PPFD) is an important factor to consider when determining how an LED grow light will perform in a cultivation facility. Several factors play into PPFD, including the design of the fixture array, fixture height above the canopy, intensity of the fixture, and most importantly, the angular distribution of light exiting the fixture - which largely defines the 'uniformity' of the fixture. 

Coefficient of Utilization (CU) is a measure of how much light exiting the fixture will fall on a canopy area of a certain size; CU is an important factor to consider in designing an energy efficient Controlled Environment Agriculture (CEA) facility. CU is expressed as a ratio of the total light emitted by the fixture to the light that falls on an area of canopy of a defined size. It is important to note that the light that does not fall on the canopy directly under the fixture may either be wasted (to walls or floor), or may fall on canopy area adjacent to the fixture, depending on the design of the facility. 

The only accurate way to determine CU is by simulation, since each measurement technique previously discussed is not without its limitations. When we designed our RAY Reflectors, we simulated the entire fixture in a ray tracing simulation tool which uses Monte Carlo calculation methods and ray data from LED manufacturers to calculate the light output of a 3D model of FluxScale 600TL, accounting for all of the materials in the product, each LED, operating and drive conditions, and geometry of the fixture. 

   FluxScale Reflectors  were designed with ray tracing techniques, ensuring highly uniform lighting on the canopy

FluxScale Reflectors were designed with ray tracing techniques, ensuring highly uniform lighting on the canopy

Calculating CU from a simulation is simple; first calculate the entire light output of the fixture, then measure the output incident on various sized planes at different distances from the fixture. The ratio of these values is representative of the percentage of light that hits a plane of a certain size at a certain distance. As you will see, increasing the distance of the plane from the fixture results in a lower coefficient. Shown below are CU values for FluxScale 600TL on a 5x5 foot plane at three distances. Adding our FluxScale Reflector significantly increases the CU. 

It is important to understand that the light that does not fall on the canopy directly under the fixture is not always wasted. With efficient CEA facility design practices, this light can be reflected off highly reflective walls or will fall on canopy area adjacent to the fixture, depending on the design of the lighting array.

1ft distance2ft distance3ft distance
FluxScale (no reflector)0.890.680.47
FluxScale with RAY Reflector0.990.820.60

This table might be easier to understand visually:

  Our RAY Reflector is designed to result in highly uniform lighting across large canopy areas, with whole array Coefficient of Utilization (CU) exceeding 0.95, depending on wall reflectivity and array layout.

Our RAY Reflector is designed to result in highly uniform lighting across large canopy areas, with whole array Coefficient of Utilization (CU) exceeding 0.95, depending on wall reflectivity and array layout.

Wind tunnel optimization of FluxScale cooling

We are obsessed with energy efficiency and reliability at GrowFlux. When our engineers set out to squeeze every last bit of efficiency out of our FluxScale LED fixtures, they took a very close look at the cooling fans.  

FluxScale uses two high performance IP68 waterproof ball bearing fans to provide cooling to the 318 tunable LEDs, allowing these devices to efficiently convert electricity to photons. FluxScale automatically adjusts the speed of these fans in real time based on an array of temperature sensors placed among the LEDs. The fans are hosted on a user serviceable fan tray which interfaces to the cooling fins within the fixture - the aerodynamics of these assemblies has a significant impact on fan performance. Minor design adjustments can result in enhanced airflow, allowing FluxScale to operate the fans at lower speeds, improving the energy efficiency and reliability. 

  FluxScale features a removable fan assembly, making it the only horticultural lighting fixture in the industry designed to facilitate rapid maintenance of cooling fans. FluxScale is designed for very low fan failure rates, however in the rare occurrence of a fan failure, fixtures can be serviced on site in minutes. 

FluxScale features a removable fan assembly, making it the only horticultural lighting fixture in the industry designed to facilitate rapid maintenance of cooling fans. FluxScale is designed for very low fan failure rates, however in the rare occurrence of a fan failure, fixtures can be serviced on site in minutes. 

Assessing these design features can be done with computational fluid dynamics (CFD) simulation tools, however nothing compares to real world measurements on physical hardware. GrowFlux worked with engineers from ebm-papst, a world leader in cooling fans and motors, to optimize the performance of the the removable fan assembly and cooling fins. 

  FluxScale 600AC instrumented and connected to a wind tunnel at ebm-papst. This tunnel precisely measures airflow; laser tachometers measure fan speed, and other instruments measure power and thermal performance.

FluxScale 600AC instrumented and connected to a wind tunnel at ebm-papst. This tunnel precisely measures airflow; laser tachometers measure fan speed, and other instruments measure power and thermal performance.

The first step in assessing the cooling performance of the fans within FluxScale is to instrument the fixture with temperature sensors attached to various components inside the fixture; lasers are directed at the fan blades to allow optical tachometers to measure actual fan speed.

In addition to these instruments, every FluxScale fixture is able to internally measure 9 temperature points across the LED array as well as real time fan speed - in normal operation these measurements are reported to the GrowFlux Cloud Control solution for quality assurance within our PrecisionPAR management service. 

  Pressure plot showing the relative performance of various fans and fan speed settings against the system airflow resistance within FluxScale.

Pressure plot showing the relative performance of various fans and fan speed settings against the system airflow resistance within FluxScale.

ebm-papst engineers then attached FluxScale to a calibrated wind tunnel.  The wind tunnel is designed according to AMCA210, a standard which establishes laboratory methods to assess the aerodynamic performance of fans. The principle of the chamber is to measure the differential pressure through an array of nozzles. The differential pressure, along with the geometry of the nozzles, is used to calculate a volumetric flow rate of the air moving through FluxScale. An auxiliary blower on the chamber is used to remove any pressure drop caused by the air flow chamber. This assures that FluxScale is being measured at its true operating conditions. Input power, current draw and fan speed are all recorded during the measurement. Subtle design changes were made to the FluxScale fan assembly to fully optimize performance.  

  Thermal image showing the LED array within FluxScale operating at full power, indicating effective and uniform cooling due to the low board temperatures and absence of a central hot spot in the middle of the LED array.

Thermal image showing the LED array within FluxScale operating at full power, indicating effective and uniform cooling due to the low board temperatures and absence of a central hot spot in the middle of the LED array.

The detailed analysis of fan selection, fan speed, and design for optimal airflow using these tools is a small part of the work GrowFlux has done to ensure optimal cooling of its LEDs. Effective cooling of LED emitters improves energy efficiency and longevity, allowing our customers to save more energy for a longer period of time. 

GrowFlux featured by Samtec

Samtec connectors in FluxScale LED grow lights

Samtec, a world leader in high reliability connectors for industrial electronics, recently featured our FluxScale fixture on their blog. We use Samtec connectors for one of the most critical electrical connections in FluxScale - the Engine Control Module, which hosts a powerful ARM Cortex M3 processor and has 40 high speed digital and analog connections to the underlying LED engine. 

FluxScale LED grow light and engine control module

When we designed FluxScale, we had to address the design challenge of reliably interfacing a complex multi layer processor module to our high power LED engines while withstanding heat and vibration for upwards of ten years. We selected a particular Samtec connector which offers vibration resistant electrical contacts and a locking connection in a compact footprint. As an added bonus, the connector mates with a tactile and audible click when installing the Engine Control Module, which helps us eliminate quality issues during production. Selecting quality suppliers such as Samtec is an important component of our own commitment to reliability and quality. 

Product design for ingress protection

 Microscopic view of an engineered silicone foam we use to seal FluxScale from the elements. Ball point pen shown for scale. 

Microscopic view of an engineered silicone foam we use to seal FluxScale from the elements. Ball point pen shown for scale. 

Equipment designed for challenging environments such as greenhouses and indoor farms face the constant threat of dirt and moisture ingress due to exposure to humidity and wet conditions caused by maintenance, rain, and irrigation. Horticultural lighting products in particular can be negatively impacted by ingress of moisture and dirt which severely impact the performance and longevity of the product. In many cases, ingress of dirt and moisture happens despite the equipment manufacturers best intentions- such as sealing an equipment enclosure with air and water tight seals and implementing IP 5x or 6x ingress protection.  So what goes wrong here?

Ingress happens when atmospheric pressure changes act on a sealed equipment enclosure. As the pressure changes, a small amount of positive or negative pressure develops inside the enclosure. These atmospheric pressure changes can cause a daily shift in the differential pressure between the enclosure and its environment. When negative pressure develops inside the enclosure – due to increasing atmospheric pressure – a small vacuum is formed inside the enclosure. Over time, the daily shifts in atmospheric pressure also cause wear and tear on enclosure seals. If a seal becomes compromised at any point due to stress, vacuum pressure inside the enclosure will draw moisture and dirt into the enclosure.

Standardized tests for ingress protection can be performed informally by the manufacturer or can be performed by a certified third party lab. We should note here that these tests are typically done once, in absence of cyclic changes in atmospheric pressure and normal wear and tear. Further, these tests typically won’t catch ingress of water vapor, which can later condense into liquid water, causing condensation and damage. Water vapor can also penetrate joints, seals, and materials much more effectively than liquid water since it lacks the surface tension of liquid water.

Based on our experience working with horticultural equipment and lighting, GrowFlux believes the best design practice for ingress protection is to consider the challenges presented by changing atmospheric pressure, wear and tear, material performance over time, and water vapor ingress. In designing its horticultural lighting product line, GrowFlux has employed several design features to boost our ingress protection:

Pressure equalized enclosures

Mitigating differential pressure in an enclosure is easily achieved by designing in a specialized vent which allows only a small amount of air to pass while blocking moisture and liquid water. Not everyone in the industry is doing this as it increases cost and assembly complexity, however in our experience protective vents pay for themselves. The protective vents we install in every product with a hollow enclosure incorporate PTFE fabric at the core, passing only the amount of air necessary to remove pressure from sealing gaskets. These vents are also commonly installed in high quality LED street lights.

Fully potted power supply

Our FluxScale Series fixtures use the Meanwell HLG driver, which offers the highest efficiency of any 300-600W driver we have seen on the market. This driver is also fully potted (or filled) with thermally conductive, high temperature silicone which protects the electronics inside the driver from water, dust, and moisture while also dissipating the small amount of heat created by the driver – resulting in its high efficiency. These drivers were originally developed for stadium lighting applications, and are well suited to challenging agricultural use.

 The fully potted Meanwell HLG IP67 power supply inside FluxScale. We use the highest efficiency drivers on the market in our lights!

The fully potted Meanwell HLG IP67 power supply inside FluxScale. We use the highest efficiency drivers on the market in our lights!

Gasket material selection

Gaskets, O-rings, and other compressible seals can be made of a wide variety of materials. Proper material selection and extensive design for manufacturing is critical to maintaining ingress protection in a seal; designers must consider manufactured part tolerances, material properties at operating temperature, degradation mechanisms in the seal materials, and the sealing material's ability to resist permanently compressing over time (called compression set resistance), among other factors.

GrowFlux encases LEDs in our FluxScale product in extruded T60603 aluminum and anti-reflective coated glass for optimal protection from the elements. We use an engineered silicone foam which is die cut into several custom sealing gaskets; these materials maintain their mechanical properties at high temperatures and compression force for very long periods of time. Wear and tear due to differential pressure in the enclosure is mitigated with the protective vents mentioned previously.

 Die cut silicone foam gaskets within FluxScale provide superior ingress protection

Die cut silicone foam gaskets within FluxScale provide superior ingress protection

Potted fans & sealed connectors

The GrowFlux FluxScale 600AC is a fan cooled horticultural lighting product; compared to passively cooled fixtures, lights with fans exhibit better heat dissipation, resulting in higher efficiency, smaller size, and a lighter weight fixture. To ensure that our fans are reliable in wet, humid, and condensing environments, GrowFlux directs its manufacturers to apply a a potting compound to the entirety of the fan drive circuit, rotor and winding, and internal electrical connections, protecting these sensitive components from corrosion and moisture. And since our fans are user-serviceable (in the very rare event we experience a fan failure during the 10+ year design lifetime of FluxScale), we use sealing connectors inside FluxScale to connect our fans. 

 FluxScale is the only fan cooled horticultural lighting fixture on the market with user-serviceable fans

FluxScale is the only fan cooled horticultural lighting fixture on the market with user-serviceable fans

Rated liquid tight cable fittings

GrowFlux installs high quality liquid tight cord grips in its LED engines, control modules, and fixture housings to protect cables and to further prevent ingress of moisture, water and dust. FluxScale fixtures specified for wet locations feature a waterproof twist lock power connector and heavy duty UV resistant cable designed specifically for FluxScale. We even have this cable and connector made in Chicago by the legendary industrial cable maker Switchcraft

 FluxScale specified for wet locations features a waterproof twist lock power connector

FluxScale specified for wet locations features a waterproof twist lock power connector