For over 30 years, DN Tanks has designed and built prestressed concrete tanks for stratifying and storing chilled water for the Thermal Energy Storage (TES) process. Every single one of these tanks is watertight and still operational today.


Thermal Energy Storage has been a proven technology for over three decades. TES tanks are the reservoirs used to store energy in chilled water district cooling systems. These specialty tanks are insulated and designed with special internal “diffuser” systems. This allows two bodies of water to reside in the tank during the charging and discharging of chilled water.

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Almost any chilled water district cooling system can benefit from a Thermal Energy Storage tank.


Every tank made by DN Tanks provides unparalleled reliability at the lowest cost of ownership, while still maintaining a full range of customizable options. Our TES tanks can also provide owners with significant financial benefits.


Reduced Costs

Reduces energy and operational costs:

  • Reduces energy costs by permanently lowering the peak electric demand with a TES tank.
  • TES tanks allow owners to participate in Demand Response programs, reducing their utility bill.
  • Shifting the electric power consumption of the district cooling system from daytime to nighttime, reduces electric usage.
  • TES tanks allow owners to participate in Peak/Off peak pricing programs, reducing energy costs.


Improved Power

Improves the efficiency and power output of natural gas powered electric generators:

  • TES tanks, in combination with Turbine Inlet Chilling, maximize the power output of natural gas power plants.
  • TES tanks minimize the parasitic load of the Turbine Inlet Cooling system during peak spot market generation events.
  • TES tanks can help increase power output of a non-cooled natural gas combustion turbines by up to 20%.
  • TES tanks can be added to existing Turbine Inlet Chilling installations.


Capacity Expansion

Expands the cooling capacity of an existing campus:

  • Utilize a concrete Thermal Energy Storage tank to meet increased cooling loads and avoid the capital expense of adding a new chiller, cooling tower, and pumps.
  • Utilize a TES tank to increase plant uptime and allow for more regular equipment maintenance, thus increasing cooling system longevity and efficiency.
  • Excess nighttime central plant cooling capacity can be used to charge a TES tank, then that stored TES capacity can provide cooling during the daytime.

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Mission Critical Security

Ensures owners of up-time of mission critical operations:

  • A TES tank is like a virtual battery of chilled water which can be used as a form of uninterruptible cooling for the data center.
  • TES tanks provide redundant cooling capacity in case the chiller equipment goes off-line unexpectedly or an intentional off-line condition for maintenance or “blackout testing”.
  • Many TES tanks are also dual-purpose fire water reservoirs.