Pre Cool is the practice of cooling a building below its normal setpoint during off-peak hours to reduce cooling demand during peak pricing periods. This strategy stores thermal energy in the building’s mass, allowing the HVAC system to operate less intensively when electricity rates are highest. Pre cooling typically reduces peak demand by 10-20% while maintaining occupant comfort.
Technical Details
Pre cooling works by lowering indoor temperature by 2-4 degrees Fahrenheit during hours when electricity rates are low (typically 9 PM to 6 AM). The building’s thermal mass absorbs this cooling, which then gradually releases heat during peak demand hours. Common setpoint adjustments range from 72°F to 68°F during pre-cooling windows. This approach requires automated controls and real-time pricing signals to execute effectively.
Practical Applications
Pre cooling is most effective in commercial buildings with high thermal mass, such as office buildings, schools, and retail centers. Healthcare facilities and data centers frequently employ this strategy to manage operational costs. Success depends on accurate weather forecasting and demand response program participation.
Energy Benefits
Facilities using pre cooling strategies report 15-25% reductions in peak demand charges, translating to significant cost savings. The method also reduces strain on the electrical grid during peak hours.