Thermal energy storage is like an "HVAC battery" for a building’s air-conditioning system. Trane Thermal Energy Storage systems use 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. Model C energy storage tanks store energy in the form of ice during off-peak periods when utilities generate electricity more efficiently with lower energy and demand charges. The stored ice is then used to cool the building occupants the next day, during the peak periods when utility rates are at their highest.
Built-in Convenience and Reliability
Developed in response to customer requests for more flexible siting
and faster installation of storage tanks, the second-generation CALMAC
Model C tanks can be bolted to each other due to their internal
headers and four inch flanges. Internalized headers eliminate most
external piping (80 percent!) which results in a 20 percent smaller
footprint requirement and more siting arrangement flexibility, cutting
installation cost and time of installation.
The second-generation Model C Thermal Energy Storage tank also features a 100 percent welded polyethylene heat exchanger and improved reliability, virtually eliminating maintenance. The tank is available with pressure ratings up to 125 psi.
TC_energy storage trends and gaugesNA_EN.PNG
Control strategies
There are any number of control strategies that can be utilized to
take advantage of the benefits of thermal energy storage. However,
there are two basic approaches that define the common limits of system
design. Electric rates and building usage will determine which control
strategies are best for the project.
Full Storage A chiller sized large enough to
charge enough energy storage can shift the entire load to
off-peak periods.
Partial Storage The chiller
works in conjunction with the CALMAC energy storage tanks during
on-peak periods to manage the building’s cooling load. During
off-peak hours, the chiller charges the tanks for use during the
next day’s on peak cooling period.
A secondary fluid is needed that can operate and flow at temperatures
low enough to freeze water. An ethylene-based or propylene-based
glycol solutions is recommended. A premixed solution of an industrial
heat transfer solution that is specially formulated for low viscosity
and superior heat-transfer properties should be used. Industrial based
HTF’s contain a multi-component corrosion-inhibitor system that can be
maintained and provide a long useful life.