Controlled Environmental Horticulture (CEH) is a rapidly growing industry which grows agricultural crops indoors using artificial lighting and air conditioning to replace the sunlight and air conditions that the outdoors historically have provided. The plants contained within these spaces transpire significant moisture into the room, creating large internal latent loads which change as plants progress through their grow cycle. This results in extremely energy intensive facilities (10 times higher than offices) with complicated environmental control requirements. Understanding heating, ventilation, air conditioning, and dehumidification (HVAC-D) operation within CEH facilities is important, not just because of the intensive energy requirements, but because the performance of these systems is directly related to crop yield and owner bottom line.

This presentation focuses on a field study conducted at (2) cannabis grow facilities located in Sacramento, CA which sought to understand HVAC-D requirements in grow rooms by completely characterizing the thermal loads existent in a typical grow room. We will explore the unique thermal aspects of grow rooms, how the latent load changes over the life of a plant, how this latent load interacts with its environment, and how an environmental control system should be designed to achieve energy efficiency and optimal space conditions.