Can We Talk? Portland Event Provides Grow Room, HVAC Language Lessons

October 2017
News Releases


What would it take for the different parties involved in grow rooms and their HVAC systems to help each other move towards a more energy efficient industry model?

For those professionals gathered at a recent event organized by the Portland, Oregon-based Resource Innovation Institute (RII), the answer became finding common ground. Titled “Emerging HVAC Solutions for Cannabis Grow Operations,” attendees of the event discussed how the road there is bumpy and problematic.

Jesse Peters, an owner/grower with Eco Firma Farms, said, “The issues for all indoor grows surrounding temperature and humidity are complex. Air within the space is in constant flux due to plant biology and watering methodology. This in turn makes it difficult for HVAC providers to get the appropriate equipment to growers.”

In his presentation to attendees Keith Coursin, president of Desert Aire, said language is the basis of many challenges between growers and their HVAC equipment providers.

Mr. Coursin said, “Growers and the HVAC industry speak different languages. That makes it hard for growers to tell us as manufacturers the precise conditions they want in their grow rooms. And harder still for us to deliver.” 

Mr. Cousin noted it is easier for the two parties to agree on the desired outcomes. Those include to maximize yields, eliminate mold/mildew and to minimize energy costs.

As an example of the language barrier Mr. Cousin cited the grow room and indoor farming term Vapor Pressure Deficit. Called Vapor Pressure Difference by the HVAC industry, the term refers to the process where plants react to air temperature and humidity conditions within grow rooms. 

Differential pressure drives transpiration – the force for nutrients to be brought from root systems to the upper areas of plants. Leaf temperatures determine the vapor pressure in leaves. Air temperature and humidity determine vapor pressure in the air. The deficit or difference creates the potential for evapotranspiration, where water drawn up from the roots and plant stems evaporates through the microscopic openings in plant leaves called stomata into the surrounding air.

The vapor pressure deficits (VPDs) targeted by growers have a significant impact on plant health. VPDs can also have a significant impact on HVAC equipment, especially dehumidification equipment used to control absolute humidity. In combination with VPDs, the design conditions sought by growers such as temperature, relative humidity and dewpoint temperature impact the costs associated with HVAC equipment. These costs include capital costs and monthly energy costs.

Given this complex interrelationship it’s easier to understand the importance of HVAC processes to all the parties involved in grow rooms and indoor farming. Those parties include not only growers and HVAC equipment suppliers. Other groups with a vested interest include architects, contractors, engineers and utilities. All were in attendance at the Resource Innovation Institute event.

Jesce Horton, a grower with Panacea Valley Gardens and RII board member, said, “It all begins with the plant. Optimizing what happens in the grow space effects each business in the supply chain and the consumers. That’s huge.”

Derek Smith, RII’s executive director, was excited to see attendance at the event exceed targets. Mr. Smith said, “We clearly advanced the dialogue in the marketplace. The cannabis industry still has so much to learn as it scales and progresses. So the knowledge transfer between professionals is really helpful as the market accelerates.”

Photo 1: Derek Smith of the Resource Innovation Institute makes his opening remarks.
Photo 2: Keith Coursin of Desert Aire shares insights on language barriers.    

Editor’s Notes:  The Resource Innovation Institute has chosen Keith Coursin, president, Desert Aire to serve on its Technical Advisory Committee. The Committee’s mission is to guide the cannabis cultivation industry toward resource efficient production. If you would like to have a Desert Aire expert speak to your peers and professional association about a challenge you face, give us a call at 262-946-7400; or use one of our website’s Contact Us forms.