Cool Thermal Energy Storage Seminar Report / pdf/ ppt download
Abstract : Thermal energy storage(TES) systems store a sizeable quantity of “cool” thermal energy that helps meet the cooling load of a building. A typical system consists of a large vessel filled with water or brine that may contain multiple small containers (e.g., encapsulated bricks or balls) filled with a material (such as water) whose liquid/solid phase-change temperature is lower than the building’s chilled-water temperature. In anticipation of periods requiring large cooling loads, typically at night, a chiller produces chilled water or brine that flows to the vessel, causing the encapsulated material to solidify (change phase) and creating a low-temperature reservoir. In other systems, an ice harvester may produce ice. When the building requires cooling during the day, the chilled water line passes through the TES tank to chill the water and provide cooling, decreasing the chiller’s load during the day. TES storage capacities of installed systems have ranged from 100 ton-hours (350 kWh) to 29,000 ton-hours (102 000 kWh). 1Most TES systems are ice- or water-based, with only a small fraction using a phase-change material (PCM) other than water.1 Typically, nonaqueous PCMs are hydrated salts with a phase change temperature of 47°F (8.3°C), according to Chapter 34 of the 2003 ASHRAE Handbook—HVAC Applications. Dorgan and Elleson2 and the 2003 ASHRAE Handbook describe different types of TES in greater detail. Please find the following attachments here"Cool Thermal Energy Storage Seminar Report / pdf/ ppt download" here ......
Nightime energy will always be cheaper or equal to power at night. The local utilities know that the largest usage comes during the day and you pay a premium for large blocks of that power. Daytime stress on the power grid can tax major metropolitan systems with aging infrastructure (the American NE Metropolitan areas for instance, see the blackout in the Summer of 2003) and the utility providers provide that negative incentive to encourage customers to use less energy at those peak times.
Smaller markets and low energy consumers usually don't see much in the way of these demand charges which fluctuate almost day to day (depending on the market).
Large energy consumers (like data centers) can see substantial demand charges for power, as such can see savings in peak load reductions. We found that the additional infrastructure and space that had to be dedicated to these systems did not pay off against the savings.