Sometimes the smallest of voices carries the grandest, biggest solution. This is the approach that Terry Van Gelder has learned over his more than 20 years of agriculture sector and 35 years of construction experience. Terry has been designing a number of facilities for private industry and the US military. “Exactly like greenhouses for medical cannabis, military facilities must comply with specific and precise regulations.”
When Terry eventually switched to high-tech cultivation, he found himself deeply dissatisfied with the plethora of cannabis greenhouses in the US. “When I started working in greenhouses, I noticed that most of them did not meet the criteria required for all aspects of growing – even though they were for pharmaceutical crops,” he says. Subsequently, he designed a top-notch, eco-friendly commercially framed greenhouse, which was even awarded the Edison Innovation Award in 2019 under Energy and Sustainability.
'Deconstructing' traditional greenhouses
“Traditional greenhouse construction consists of an outside wall, a roof and then leave the structure exposed. Mold and other contaminates can grow and collect on the open steel structure and fall into the grow area. This is also true with fabric blackout systems. In California last June a random test was conducted of cannabis product on the shelf and 23% of the product was found contaminated, with mold being the worst. The contaminated inventory was destroyed which netted large losses to the growers. Soon it can be expected that here in the USA the FDA will be inspecting these facilities. I have been under FDA watch in an unrelated sanitary agriculture operation where no open structures are allowed. Full ceilings and inner walls were mandatory and required spray down sanitizers daily. I see the same scenario on the horizon for cannabis growers, full sanitization of the growing room after each crop rotation."
Terry further recounts that he has seen many growers struggling with varying climate zones within the greenhouse. "This is one of the main problems I addressed when designing the AGT Hybrid Greenhouse."
An innovative design
“A core feature is AGT completely encases the structure itself, so no exposed framing system," he describes. "Our system utilizes a double wall and roof/ceiling system. It has a glass/Lexan sunroof and an electro-chromatic glass ceiling,” he describes. "For those not familiar with electro-chromic glass, it’s a high-tech product which transitions from clear to complete blackout by low voltage current. This glass can be set at any light transmission desired by the grower. It’s also set up to operate in grids, if you want an 80’ x 80’ grid at 70% light you can manage it with your iPhone from 1000 miles away. The blackout feature of this glass eliminates the need for the cumbersome fabric blackout system. Our system is designed on a per job basis and the customer can select any type of glass, Lexan product or building size configuration."
He continues: “So with this system, you have a sealed air chamber, which is from the roof to the ceiling (approximately 36” deep), and it continues down in between the inner and outer walls. This creates a large air plenum at the roof and wall cavities which is a natural insulation barrier. This air plenum completely traps all the heat developed by the steel structure, precisely why traditional greenhouses have micro climate zones all over the greenhouse because of the open steel structure. Understand the open steel structure has to be cooled in hot climates and warmed in cold climates, a negative use of energy. With the heat contained in the air cavity you have a precise amount of cubic feet of air to manage just like in office space. You have a length, width and ceiling height with no major heat variables to affect the air management system. In hot climates the trapped roof heat can be exhausted or stored underground and reused in the growing rooms. Even in cold climates, the sealed roof cavity will produce heat which can be recycled back into the growing rooms.
Air management through the roof
Another use of the roof and wall air cavity is the air management systems. "All return air flow is directed through the roof and wall cavity, so no ductwork," he explains. "Heat naturally rises so there are return air vents in the ceiling. Each one of these vents utilizes an oil laden filter capable of pressure washing and designed to kill everything, be it fungi, pollen, insects, and cross contamination from room to room. As such, all our systems have been placed under “Patent Pending “protection."
The benefits of a commercial framing
“We do not use traditional greenhouse framing because of long delays in receiving the product, the excessive use of small parts and most of them are proprietary. Thus, you have a hard time finding people to erect these structures, it’s not a common framing system in the construction industry. That is why we use commercial steel frames, for immediate availability and constructability.” It’s a framing system all commercial steel erectors know and build. And with a commercial framing system you are not limited on weight support off the ceiling structure. These structures can support any type of roof mounted automation, water booms, lights, fire sprinkler systems, etc. These structures are the same used when we build aircraft hangars for the military. Its routine to support 5-ton to 10-ton bridge cranes directly of the ceiling structure with no support columns. Whether you are building 50,000 SF or 500,000 SF, our delivery remains at 4 months from production release date.
An underground system
“AGT also offers an underground mechanical system because it is more efficient, especially in cold countries where dehumidifiers pull out much heat,” he explains. “That heat is thus put back into the heating chamber underneath the structure, or it can be exhausted if you are in a very warm environment. Large amounts of air can be managed in the mechanical basement in an insulated air management environment."
A video showing the system
In addition to that, Terry points out that under development are AGT Climatech growing tables, CRAM onsite power generators and SEGS, a inverted lens solar system used for super heating of oils for heating or power production.