Thermal energy storage is like a battery for a building’s air-conditioning system. It uses standard cooling equipment, plus an energy storage tank to shift all or a portion of a building’s cooling needs to off-peak, night time hours. During off-peak hours, ice is made and stored inside energy storage tanks. The stored ice is then used to cool the building occupants the next day.
How much electricity is consumed, or the amount of kilowatt-hours (kWh) used during a billing month. Charged as ₡/kWh. But that is only part of the energy bill.
How much electricity is needed in a timed interval and what time of day, or the peak number of kilowatts (kW) consumed during a 15- or 30-minute interval within any billing month. Typically charged as $/kW monthly, but charges can be converted to $/ kWh. Prime time electricity causes a high demand which increases prices.
The tanks are designed to shift load from day to night changing how much electricity is needed at peak times of consumption (Demand), thus lowering your peak demand and saving you up to 20% or more on your bill.
Example: Your building uses 100 tons of cooling from the chiller. Your demand charges are $15.00/Demand kW and your chiller uses 350 Demand a Month.
You pay 350 kW x $15.00 = $5,250.00/month for your AC LOAD.
Your off peak Thermal Ice Plant loan payment a month is $1,400 per month. Your net financial benfit (keep in mind energy costs go up annually too) is $5,250.00 - $1,400.00 = $3,850.00 per month or an annual savings of $46,200.00 annually.
For every four buildings cooled by thermal storage, a fifth can be cooled also, without the need for additional power plants. The cumulative effect of less peak demand across multiple buildings, generates enough extra cooling capacity to address the cooling needs of a fifth building. Lowering peak demand brings other significant benefits too.
Thermal storage can help green building professionals and building owners achieve LEED® points in Energy & Atmosphere (EA), the largest credit area for both new and existing buildings. With this credit, earn up to 18 points by surpassing ASHRAE standards by up to 50%. For new construction only, thermal storage, can help reduce energy costs 10-20% and gain up to 10 points. The ASHRAE Standard is based on energy cost savings, not energy savings. So cost is the metric to drive technology choices such as thermal energy storage in new construction.
Demand Response Point EA4
This new credit allows up to 3 points. New construction (2 points) and existing buildings (up to 3 points). Obtain points by participating in a demand response program.
Thermal storage can also help earn demand response credit for permanent load shifting (existing buildings only).
Have in place during the performance period a system, which permanently transfers electricity demand from peak hours to off-peak hours as defined by the local utility provider.
Demonstrate that the facility is successfully reducing peak demand by 10% during the performance period as compared to peak electrical demand.
LEED® CERTIFICATION is a program by the United States Green Building Council (USGBC). This page provides a brief summary of credits.