CEA Facility Design

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.