Many of you are facing the unprecedented case of completely empty buildings. While occupant health and comfort are normally your primary concern, empty buildings present an opportunity to greatly reduce your utility spend. By engaging in the setback practices outlined below, you can reduce your energy bills by 10-30%.
Steps to reduce energy cost during low-occupancy*:
Schedule Air Handling Units off. This can be done in your building automation system. Schedule associated exhaust fans concurrently. During the current shoulder season, it is unlikely space temperatures will drift very far from setpoints. Alternately, place VAV Boxes in “unoccupied” mode with setpoints at 60-80°F.
Chiller Plant control. If your chiller plant is enabled on outside air temperature, increase enable setpoint from 50°F to 55°F, or even 60°F. If your building is empty or nearly empty, its unlikely to have much of a cooling need and chillers can remain off.
Command all space temperature setpoints to a consistent temperature range: e.g. 68-75°F. In typical operation, occupants have control of their space temperature via their thermostat. In reduced occupancy conditions or in an empty building, consistent space temperature setpoints will eliminate simultaneous heating and cooling. Also broadening the deadband (temperature range between heating and cooling) will reduce energy use.
By engaging in these setback practices, you can reduce your energy bills by 10-30%.
Reduce ventilation in an informed fashion. If space ventilation is purely occupant driven, reduce minimum outside air damper position to half of its current setpoint. If spaces require exhaust, pressurization, or 100% outside air (such as a laboratory) this does not apply.
Laboratory Considerations. Strongly engage best practices: drop sashes, utilize unoccupied mode, evaluate for reduced supply and exhaust flow and reduced face velocities.
When normal occupancy resumes:
It is critical to document any adjustments made, so system parameters can be returned to normal operating mode, especially with regard to ventilation.
ETC Group can talk you through the details. Email us at email@example.com or call us at 801-278-1927.
* The recommendations above are general in nature and assume that you are aware of all of the requirements of your spaces. If spaces require special exhaust, pressurization, or contain hazardous materials, these suggestions will not apply. Please give us a call for specific facility level support. Let’s make a difference together.