When looking to cool a commercial environment there are two types of cooling that should be considered: comfort cooling and process cooling. Comfort cooling is the same type of cooling system that can be found in residential houses and office buildings. It is designed to cool spaces primarily to create comfortable temperatures for occupants.
Process cooling is typically less familiar to the typical consumer. However, it is no less common than comfort cooling. Process cooling is designed for heat processing and removing large amounts of heat from a space, which is commonly done with a chiller system. Chiller systems are commonly found in data centers, plastic injection molding and airports and hospitals - large buildings requiring a lot of heat to be removed.
Chiller systems are typically used for high heat and large commercial environments because they provide a number of benefits over process cooling under such circumstances.
- N+1 redundancy is much more cost effective with a chiller system. In order to provide full system redundancy, with comfort cooling systems, an additional cooling unit is required for each room.With chiller systems, only one additional chiller unit is needed for the entire system in order to provide full system redundancy. This reduction in equipment needs results in system redundancy being much more cost effective with a chiller system.
- Specific to indoor gardening, chiller systems are more cost effective when designed to be used on a “flipped” light schedule than comfort cooling. With comfort cooling, the number of compressors remains the same, even if only half of the available lights will be turned on at a single time. This is due to individual compressors being tied to individual rooms. With chiller systems, it is possible to reduce the number of compressors needed by half when running on a “flipped” light schedule. Since compressors are tied to the overall system, and not individual rooms, the amount of equipment needed can be based on the peak load of the system, rather than the number of rooms.
- Chiller systems do not suffer from frozen evaporators or cooling coils which is common in comfort cooling systems when used in high humidity environments. With chiller systems, the cooling coil temperature never drops below 45°F, which is the set point of the chiller system. However, with comfort cooling systems, the refrigerant in the system is naturally below freezing and warms up as it passes through the cooling coils. Ice can form at the point where the refrigerant begins to boil off. In humid environments, the evaporator and coils are highly likely to freeze due to the added moisture in the air.
- Free cooling in the winter. With chiller systems, it is possible to add dry coolers to the system in order to cool water during the winter without running the compressors. This chilled water can then be used to cool the interior of the building without ever coming into direct contact with the air in the room. Alternatively, with traditional cooling systems, in order to achieve free cooling in the winter, outside air must be brought into the grow room. This can cause a number of problems, including the introduction of pathogens, reduction in CO2 levels and humidity spikes.
- Chiller systems do not require ducting, using plumbing instead. Ducting, which is required to move air around in comfort cooling systems, is expensive and creates an ideal breeding ground for mold and other pathogens if not cleaned regularly. Instead, chiller systems utilize plumbing to move liquid throughout the facility, allowing for sealed rooms and a cleaner form of cooling rooms.
- Process cooling equipment is designed for year-round operation. Comfort cooling is not designed to be used year round. It is only designed to be used in the warm, summer months when spaces need to be cooled in order to make human occupants more comfortable. However, the high, year-round heat loads found in an indoor garden require cooling systems to run year-round, which can cause comfort cooling equipment to wear out and significantly shorten its life expectancy. Chiller systems, on the other hand, are meant to be run year-round, as they are designed to remove high amounts of heat, rather than make space comfortable for human occupation.
Know your options when selecting HVAC for a garden environment, and consider these factors before making your final selection. With monthly cooling costs amounting to as much as 46% of electricity usage, the system you choose will have a large impact on your company’s bottom line.