Fall has arrived, and along with it, more temperate weather across the Northeast and Mid-Atlantic. The shoulder season, as we call it in facilities operations, exists between peak cooling season (late May through mid-September) and peak heating season (mid-October through March). With decreased demand for cooling, and only mild heating demand, the forthcoming weeks bring an opportunity to curb energy consumption by taking advantage of favorable outside air temperatures.
With the appropriate control functionality, cooling equipment can be locked out based on outdoor air temperature. In the event that indoor spaces require some cooling, air-side systems can intake additional outdoor air at mechanical dampers, provided conditions are favorable. What do we mean by favorable conditions? Typically, this would mean cool air (55-65°F) with a relative humidity (RH) less than the indoor space humidity (ideally 40-60 %RH). The increase in outdoor air often referred to as “free-cooling” or “economization” is less energy intensive than mechanical cooling. This translates into dollars saved while still adequately tempering your indoor environment.
Much of these sequences should happen behind the scenes in your computer-based temperature control system. Care should be taken to ensure that these sequences operate as designed, and that mechanical cooling and heating demand is limited during a free-cooling event. Facilities operators will also want to confirm control sequence and outdoor air damper functionality. Free-cooling can be hampered by faulty coding or equipment function. The Stone House Group recommends the use of this sequence during our energy auditing process. When providing retro-commissioning services, The Stone House Group will test the control logic associated with economization to ensure proper functionality between the temperature control system and the physical air-handling equipment responsible for space tempering.
The Stone House Group is available to help implement and or confirm the proper operation of free cooling at your facility today.