Controlled Climate
Systems

Surna provides energy and resource efficient technology solutions that allow growers to meet the unique demands of controlled agriculture environments.

surna dry cooler

We’ve often referred to the importance of HVAC systems to every layer of the cultivator’s business, but how do you choose which approach is right for your facility?

The truth is, there are a number of technologies that can successfully manage the climate in an indoor facility. One of our most important responsibilities as your design partner is to review with you all options in depth, along with budgets and their respective pros and cons, to assist with the decision-making process. Your goals, not ours, inform the design process. Our job first and foremost is to understand your goals, and then to design a system that best meets those goals. There is no substitute for a conversation with one of the experts on our team and the wealth of knowledge that comes along with it. If you’re not ready to call us quite yet, you can find a summary of some of the HVAC-D technologies in which we specialize below.

3 Easy Steps to a Successful Climate

Contact Us

We’ll have a brief discussion about your facility and the goals you are looking to achieve with it.

Review Your Options

We’ll clearly articulate the cultivation system options available to you to help make your decision process easier.

Receive a Solution

You’ll receive a customized solution to meet your specific goals.

Standalone Systems

In variable refrigerant systems, refrigerant volumes are modulated and distributed to multiple areas of the building depending on cooling needs at any given time. With this type of system, multiple fan coils or air handlers can be connected to a single condenser, allowing condensing units to be shared between spaces without sharing air, (similar to chilled water systems with slightly less flexibility). The ability to modulate refrigerant based on current cooling requirements and move cooling to areas of the building that need it result in a very high listed EER, although this is based on comfort cooling applications and cultivators are unlikely fully capitalize on the high efficiency ratios due to the largely constant cooling load in most cultivation facilities.  Temperature is controlled by air handlers or fan coils and dehumidification is controlled by separate, stand-alone dehumidifiers. This approach may be a good option for cultivators seeking an improvement in energy efficiency and redundancy over standard light commercial HVAC systems, or cultivators whose authority having jurisdiction are calling out a specific EER for regulatory compliance.

Technology Options:

  • Low ambient kits
  • Multiple air handler/fan coil configurations
  • Ground or roof mounting options
Variable Refrigerant Systems
hvac system from surna
This describes a system in which chilled water, as opposed to refrigerant, is utilized as the primary means of heat exchange in the cultivation space. From a climate management perspective, it operates very similarly to typical refrigerant based HVAC systems with dehumidifiers. Temperature is controlled by air handlers or fan coils and dehumidification is controlled by separate, stand alone dehumidifiers. However, 2-pipe chilled water has a number of advantages over stand alone DX systems, including longevity, redundancy and electrical infrastructure reductions. With this type of approach, air handling systems operate independently of the compressors, allowing one central plant to operate multiple rooms without mixing air between rooms. This results in the ability to reduce electrical infrastructure, and offers greater opportunities for redundancy at lower cost. Further, chillers are generally designed for heavy commercial or industrial applications, resulting in less maintenance and a much longer life cycle. These types of systems are a great option in extreme climates or when redundancy, flexibility, and reduction in connected load is a high priority.

Technology Options:

  • Extreme low/high ambient operation
  • In colder climates, substantial free cooling opportunities (with or without ventilation)
  • Ducted or ductless air handler options
  • Affordable custom air handler configurations for spatial or structural constraints
  • Ground or roof mounting options

Integrated Systems

Hot gas reheat systems are refrigerant based, DX systems, designed to integrate cooling and dehumidification operation within a single system. This allows for greater precision than with stand alone dehumidification systems, and reduce or eliminate the need for additional, stand alone dehumidifiers, which can improve energy efficiency and reduce electrical infrastructure requirements. In these systems, the refrigerant circuit is routed through the airstream twice—once to remove BTU’s (heat and humidity) from the air, and then to replace the heat back into the airstream to make dehumidification operations temperature neutral (or allow for dehumidification when temperature modification is not needed). Integrated controls manage the flow of refrigerant, allowing for a relatively simple front-end controls interface. Longevity is generally superior to standard, comfort cooling-style DX systems as these systems are intended for cultivation applications, while installation requirements are similar to standard HVAC systems. These types of systems are a good mid-range cost option between cost, electrical infrastructure and complexity, where energy efficiency and longevity are generally superior to stand alone systems.

integrated dx air handler bank

Technology Options:

  • Modulating Hot Gas Reheat for greater precision
  • Ducted or Ductless air handling options
  • Affordable custom air handler configurations to accommodate special climate needs or spatial/structural constraints
  • Low ambient kits
  • Heat pipe technology to reduce connected load and energy consumption
  • Desiccant technology to enhance dehumidification capacity and reduce connected load and energy consumption
  • Ground or roof mounting options

Testimonials

Even when project issues developed that were not Surna’s responsibility to deal with, the Surna team was more than willing to come to the table to help with resolving these issues.

Andrew Speraneo   |   Fager-Mcgee Commercial Construction

In the numerous times I have worked with the Surna team, I have always been satisfied with the quality and service I received.

Andrew Lange   |   Ascendant Manager

We’ve always recommended the Surna system for as long as we’ve had it because it’s just another thing we don’t have to worry about.

Drew Stuart   |   High Desert Relief
4-Pipe Chilled Water

Four pipe chilled water describes a system in which chilled water is the primary mechanism for heat exchange for both temperature and humidity management. The airstream is routed first across a chilled water coil to remove heat and humidity, followed by a reheat coil to ensure temperature neutrality when operating in dehumidification mode, which allows for substantial reduction or elimination of stand alone dehumidifiers, improving energy efficiency and reducing electrical infrastructure requirements. Reheat is accomplished through heat recovery chillers, reusing the heat produced by cultivation operations, with boilers as back up. With this type of approach, air handling systems operate independently of the compressors, allowing one central plant to operate multiple rooms without mixing air between rooms, allowing for further reductions in electrical infrastructure as well as cost effective redundancy. Four pipe chilled water utilizes a sophisticated controls system, which provides visibility into every area of the climate control system, allowing for significant data analysis by the cultivation team as well as by the engineering team to fine tune the system to ensure maximum precision with minimum energy consumption. These systems usually result in the tightest precision, most redundancy, highest flexibility (in both air handling options and achievable results), lowest electrical infrastructure requirements, and longest overall lifespan of all available options. Four pipe chilled water is the preferred option for cultivators for whom the maximum precision, flexibility, and insight into facility operations are a high priority.

Technology Options

  • Ducted or Ductless air handling options
  • Affordable custom air handler configurations to accommodate special climate needs or spatial/structural constraints
  • In colder climates, substantial free cooling opportunities (with or without ventilation)
  • Extreme low/high ambient operation
  • Heat pipe technology to reduce connected load and energy consumption
  • Desiccant technology to enhance dehumidification capacity and reduce connected load and energy consumption
  • Ground or roof mounting options
In vertical or multi-tier applications, airflow to both the canopy and to the HVAC system is obstructed. Thus, special attention must be paid to airflow strategies to ensure that the environment is homogenized (all plants are seeing the same climate conditions), and that the HVAC system has access to all of the hot, humid air generated at the canopy level. It can be exceptionally difficult for cultivators to find and incorporate a well-designed airflow system for their racking design. One size fits all strategies without proper engineering can be difficult to dial in, often resulting in improper air speed over the canopy, uneven temperatures, higher than necessary cost or higher than necessary energy use. Surna can provide the most effective systems that are incorporated into the HVAC design, where the cold and dry air leaving the air handling units is mixed with room air before being delivered, at the perfect temperature and humidity, directly to the canopy. This displaces the warm, humid air from the canopy, ensuring homogeneity and that the HVAC system has access to canopy air. This approach minimizes cost and energy use and ensures the best homogeneity by ensuring that each design is optimized for the specific application.
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Photo credit: Fluence

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