What type of heat rejection option should be used?
Generally, an air-cooled system has the least up-front cost. However, installation cost will be more than that for a water-cooled or glycol-cooled system since the refrigeration lines that are run between the indoor unit and outside condenser must include proper slopes and traps. These constraints do not apply to water or glycol lines. Standard outside condensers used in air-cooled systems can operate at ambient temperatures of -20F. The optional Lee-Temp configuration increases this range to -30F. Be careful to check with local codes. To minimize energy consumption some jurisdictions require the use of cooling systems that incorporate air or water economizers. Introducing large amounts of outside air prohibits the control of humidity in the critical space, which is unacceptable. A good solution is to use a system that includes a “free” cooling coil (“Glycool”).
