Thermal Energy Storage System (TES)
The Thermal Energy Storage (TES) system is a vital component of the Collier County Public Schools (CCPS) commitment to fiscal responsibility and environmental sustainability. Fiscal responsibility is one of the five priorities set by the District School Board of Collier County. By implementing TES, the District reduces energy consumption during peak hours, lowers electricity costs, and enhances the long-term efficiency of school facilities. TES also supports CCPS's broader sustainability goals, reinforcing the District’s leadership in responsible environmental practices in both school construction and operations.

1. What is Thermal Energy Storage (TES)?

Thermal Energy Storage (TES) is a system that stores chilled water during Off-Peak Demand hours for use during Peak Demand hours. During Off-Peak hours, the chiller plant produces chilled water, which is then stored in the TES tank. The tank’s capacity is designed to hold enough chilled water to cool the school through the hottest day of the year, covering the entire school day.

Most buildings in Collier County Public Schools (CCPS) are cooled using chilled water. This is achieved through a chiller plant and its associated air conditioning systems. The chiller plant produces very cold water, typically between 40 - 46 degrees Fahrenheit, which is then circulated through the building via pumps. As the chilled water moves through the building, it absorbs heat, warming up in the process. Once the water reaches a warmer temperature, it returns to the chiller plant, where it is cooled again, releasing the absorbed heat into the atmosphere. The chilled water is then recirculated to continue the cycle of heat removal, effectively cooling the building's interior.

The chiller plant and its equipment consume a significant amount of electricity—roughly half of a school's electric bill goes toward operating the chiller system. CCPS benefits from special electric rates designed for large energy consumers like schools. These rates include a Peak Demand Electric Rate and an Off-Peak Demand Electric Rate. The electric service provider determines when these rates apply. Peak Demand Hours occur during the hottest parts of the day, when electricity demand is highest, while Off-Peak Demand Hours occur later in the evening and overnight, when demand and costs are lower.

To help reduce electricity costs, it’s in CCPS’s best interest to minimize energy use during Peak Demand hours. The challenge, however, is keeping the building cool during this time, when electricity rates are at their highest. The solution: Thermal Energy Storage (TES).

2. How many CCPS sites use Thermal Energy Storage (TES)?

Of the 60 total school and support sites across CCPS, TES tanks are located on 21 sites, including Aubrey Rogers High School (opened 2023), Bear Creek Elementary (opening 2025), and the Dr. Martin Luther King Jr. Administrative Center.

3. Why does CCPS use Thermal Energy Storage (TES)?

There are several reasons why CCPS uses TES systems:

• • Significant cost savings on the school’s electric bills.
  • Incentives from Florida Power and Light (FPL), including rebates for building and using TES systems.
  • Extended lifespan of the chiller plant, as TES helps reduce wear and tear on the equipment.
  • Backup cooling: TES provides up to one full day of cooling in the event that the chiller plant is not functioning properly.
    
    

4. What are the financial benefits of TES on the Bear Creek Elementary School campus?

• • Estimated electric bill savings (annual): $103,000
  • Estimated FPL rebate (estimate): $323,000
  • Estimated Federal Inflation Reduction Act (FIRA) savings: $440,000
  • Cost of TES tank installation: $1,100,000
  • Payback period (number of years for the electric bill savings to cover the cost of installation):

Cost of TES Tank: $1,100,000
FPL rebate: ($323,000)
FIRA savings: ($440,000)
Adjusted first cost of TES Tank: $337,000
Simple Payback = $337,000/$103,000 = 3.3 years

5. Why is the TES tank for Bear Creek Elementary located near Immokalee Road?

Several factors influenced the placement of the TES tank:

1. 1. Site constraints: The campus layout includes essential features such as the building footprint, stormwater retention areas, driveways, parking lots, playgrounds, and a playfield. To optimize space for these features, the TES tank was positioned away from them but close to the building’s chiller plant.
   2. Minimizing pipe distance: To keep construction costs as low as possible, the TES tank is located as close to the chiller plant as feasible, minimizing the distance for underground piping.
   3. Minimizing electrical conductor distance: The chiller plant is located near the point where electrical service enters the building. Shortening the distance for electrical conductors helps to reduce construction costs.
      
      

6. What is the size of the TES tank?

• • Diameter: 52 feet
  • Height: 28 feet, 5 inches
  • Capacity: 417,000 gallons
    
    

7. What is the tank made of?

The TES tank is constructed from pre-stressed concrete.

8. Will there be landscaping around the TES tank?

Yes. The TES tank at Bear Creek Elementary will be painted to complement the school’s architectural design, and landscaping will be added around it. The landscaping, visible from Immokalee Road, will help blend the TES tank into the campus environment, reducing its visual impact and enhancing the overall aesthetic appeal.

Yes, there will be a traffic signal installed at Immokalee Road and Moulder Drive.