Cultivation HVACD System Comparison Study
Introduction / Abstract
Cannabis cultivation at scale is a relatively new application in the Heating Ventilating, Air Conditioning and Dehumidification (HVACD) industry, and several approaches are regularly used and favored by designers and installation contractors. The authors, collecvely, and independently, have designed, installed, and monitored these alternaves and others. The purpose of this study is to objectively compare three different climate control systems for a cannabis flowering room. The inquiry is aimed at answering practical questions such as efficiency, installation cost, performance and maintenance cost. The flowering room under consideration is a standard sized, industrial level (24/7 operation),, double-tier, with moving ‘archive style’ benches. The room is fully indoors - no sunlight is used from the outside. The room design employs 4” insulated metal panels (IMP) on walls and ceiling, with an insulation R value of 20 installed and sealed to meet an infiltration/exfiltration rate of 0.5 ACH @ 50pa (approximately 150 CFM). The electric light is supplied by LED fixtures at an efficacy and density typical for cannabis at the time of this writing.
Two ‘VRF’ style HVAC systems (ducted and unducted) are included for this comparison because some jurisdictions have explicitly called them out in their cannabis legislation as a high efficiency option. For this study we have included the additional dehumidification equipment these VRF/Mini-split systems need to perform properly in the intended horticulture environment. The third option is an integrated HVACD system specifically designed for handling the sensible, latent, and dehumidification loads in the same horticultural application in a “packaged” arrangement.
All three systems are fully designed including ducting, diffusers, grilles and all hardware and accessories needed for a fully functioning system. There are differences in how these systems are applied properly to a cultivation space and these are highlighted throughout this document. Typical load conditions are established and simulated in an industry standard simulation software package for each and performance compared. A discussion of installation and maintenance costs and procedures are discussed with pro’s cons of each approach included to add industry perspective to the performance data.
