The fabric channel combined with the pinpoint temperature / humidity of VRF is partly responsible for the 20 percent increase in the marijuana harvest by Real Leaf Solutions.
Like most growers in the North American cannabis industry, Real Leaf Solutions (RLS), Kalkaska, Michigan is still refining its growing methods, but the two-year-old company may finally have found a state-of-the-art air conditioning design that will help produce optimal yields in the near future .
Tom Beller, RLS’s co-owner and chief operations officer, believes his latest HVAC retrofit for two 1,500-square-foot flowering rooms is an important step toward optimal harvesting goals. It consists of a material duct supplied by VRF (variable refrigerant flow) systems of six and eight tons. A combination he’ll be using when he doubles operations from 12,000 to 24,000 square feet this year. Bell’s confidence is backed by the last crop’s 20 percent yield improvement, which he attributes in part to the new HVAC design.
Beller’s HVAC retrofit team was led by machine builder Marc Burnette, President of Superior Heating and Cooling (SHC), Traverse City, Michigan. Brad Bonnville, regional sales manager at fabric duct manufacturer FabricAir, Lawrenceville, Ga .; the Fujitsu VRF team at Johnstone Supply, Traverse City; and Jeromy LaRock, West Michigan Sales Representative at Manufacturer’s Representative, Major Lozuaway, Grand Blanc, Mich.
Previous RLS-HVAC challenges revolved around getting the airflow to the plants and their soilless peat / coca mixture at the right speed, uniformity, temperature, and relative humidity (RH). The tissue duct solution contains an array of linear openings at the 4 and 8 o’clock positions on each 20 inch diameter. The Combi 70 fabric also distributes approximately 12 percent of the airflow through the permeable surface of the duct to prevent condensation. The factory-made permeability and linear dispersion result in an even air distribution of 2,500 CFM per channel run, which encourages the plants to thrive.
Meanwhile, each flowering room’s four ceiling-hung V-II Airstage Fujitsu evaporator units, powered by two outdoor heat pump condensers, can keep Beller’s preferred 77 ° F and 56 percent relative humidity within a tight tolerance of ± 1. SHC’s Burnette has set up each room so that it can be cooled / dehumidified and heated simultaneously by each of the four evaporators if required. The design is invaluable when latent and sensitive heat load shifts during light / dark room cycles cause environmental changes that cannot be overcome with conventional HVAC ventilation units. According to Beller, the VRF stabilizes and locates the temperature / RH settings without adding portable dehumidifiers or humidifiers that other grow-ops depend on.
Find the best HVAC combination
When RLS opened in February 2019 as one of the first marijuana Regulatory Agency (MRA) certified and licensed recreational and medicinal marijuana cultivation and recreational operations in Michigan, it struggled to maintain optimal growing conditions resulting in yields, that we knew could be improved upon Beller. The blooming rooms of the all-metal building were equipped with conventional DX split systems. The metal spiral ducts of the ceiling-mounted air handling units with registers every 10 feet created drafts, hot spots, and layers of air that affected yields.
Not only does the new HVAC environment increase yields, but the improved air comfort also increases employee productivity. “It (the blooming room with the fabric duct / VRF system) is a completely different environment. It is very strange to walk in compared to the other rooms, ”said Tyler Pickard, senior cultivator at RLS, who immediately gathered his cultivation team as soon as he entered to experience the difference in air comfort.
RSL also saves on energy costs because the tissue duct’s more even air distribution has been shown to be more efficient than metal duct / register systems, according to a study by the Department of Mechanical Engineering at Iowa State University. According to the study, improved air distribution leads to narrow room gradients in temperature, shortened HVAC runtimes and up to 24 percent less energy consumption compared to metal ducts.
In addition, the metal channel tends to condense in humid environments. The electroplating process of the metal duct contains toxic silver oxides that drip into the soil with condensation, are absorbed by the plants and ultimately infiltrate the cannabis user. The state governments regularly search for heavy metals and can order the destruction of a failed cannabis harvest. “Using an antimicrobial tissue channel is an advantage for us as Michigan’s MRA has the strictest heavy metal and mold testing standards in the US,” said Beller.
Preserve sanitary environments
RLS cleans every flowering room after the harvest. The disassembly and commercial washing of the fabric channel, which takes less than half a day for an employee, is also part of the disinfection process, although the fabric is antimicrobial. “Metal ducts are difficult to clean, and removing those ducts would require the additional cost of a contractor with the right equipment,” said Beller. “Washing the cloth channel just creates a more sterile environment.”
Additional disinfection measures include 100 percent bipolar return air ionization modules for air treatment devices manufactured by AtmosAir Solutions, Fairfield, Connecticut, which flood the rooms with positively and negatively charged ions. The ions disinfect and electrically bind to airborne contaminants, making them large enough to be trapped in the MERV-8 media filters in air handling equipment.
The lighter weight and ease of installation of the fabric duct enabled SHC’s two-man crew to install five canal runs 35 to 38 feet in length in less than three days without the need for heavy lifting equipment, or the dozen of 1,000 watts with two ends to the facility remove high pressure sodium vapor lights with mixed spectrum. Each run is suspended from a PVC-coated metal cable that hangs two feet below the 14-foot ceilings. Metal ducts would have taken twice as much time, disrupted a larger installation team and quick cleaning after cleaning.
Future plans by RLS envisage doubling the space by spring 2021, installing more efficient lighting with variable spectra and retrofitting the current third and fourth flowering room with a fabric duct and VRF.
About FabricAir: FabricAir designs and manufactures custom air distribution and air distribution solutions for a wide variety of applications. In 1973 we installed the world’s first fabric duct system that introduced a completely new way of thinking in HVAC and indoor climate. We continue to lead the way in innovation and proudly offer superior air distribution worldwide through sales companies and an extensive sales network. Our experienced engineers ensure ideal airflow regardless of the complexity of the project. We are headquartered in Denmark and all systems are made to measure in our factory in Lithuania. For more information on FabricAir ducts and accessories, please visit www.fabricair.com. or contact Customer Service and Technical Support at sales-US@fabricair.com or by calling (502) 493-2210.
Contact: Charles J. Justice
Vice President – Sales
John Parris Frantz