Green energy is a big topic these days, and the list of ways to generate and manage energy more efficiently keeps growing. One innovative way to use energy wisely is through the use of off-peak cooling systems. Off-peak cooling is pretty ingenious because it uses energy at night when the demand is low. Air conditioning is an energy hog, and when some of the electricity needed to cool all that air is distributed over the evening and night hours, it takes some of the burden off the energy grid at the biggest demand times of the day.
This redistributes the demand for electricity, helping to avoid brownouts and blackouts and also takes advantage of lower electricity rates during off-peak times. There are other benefits to off-peak cooling systems, too. Conventional air conditioners use more energy as they get hotter, and the more energy they draw, the less efficiently they use it. Off-peak cooling systems don’t only shift the demand for power to a different time of day, they create a more stable cooling environment that can deliver the same cooling capacity with less energy consumption.
Off-peak Cooling Basics
Off-peak cooling systems use electricity to freeze water in special insulated tanks that contain refrigerant-filled coils. These coils circulate ethylene or propylene glycol and a water mixture that’s super chilled to well below freezing. Once the water freezes, at night when energy demand is low, it’s ready to be used to cool the air the next day. This is called charging, and a charged off-peak cooling system takes very little energy to keep cold in stand-by mode until it’s ready to be used to cool the air in an office building or home.
As the building starts to warm up during the day, the air-conditioning kicks on, and the chilled refrigerant from the off-peak cooling system keeps the building’s air cool. The glycol cycles through the ice filled tanks periodically to cool back down after being exposed to the hot air, and eventually, this exchange of hot for cold melts the ice. In the evening, the system charges again, freezing the melted ice with a chiller, and preparing the system for the next hot day.