Off peak storage device

DETAILED DESCRIPTION It is an object of the invention to provide a efficient cold storage system of simple construction It is another object of the invention to provide an efficient cold storage system immune to mechanical failures induced by the thermal cycling.
It is another object of the invention to provide a modular cold storage system.
These and other features of the invention are attained in a system for ice storage to provide time offset cooling to the cooling system of a building or refrigeration unit, wherein a tank defines a storage chamber including inlet and outlet ports through which circulates a heat transfer medium, and a plurality of buoyant panels are arranged in a dense array for receiving, storing, and releasing thermal energy carried by the heat transfer medium.
In a preferred embodiment, each panel is formed of a thin film material, such as a PVC plastic, to result in a bag-like structure.
Preferably, opposing sides of the panel are fused together at discrete points to define a quilted structure having a defined maximum thickness when filled and a generally undulating outer surface which allows passage of the transfer medium between adjacent bags while determining a well-defined thin panel geometry Granular ballast at the bottom of each bag maintains the vertical alignment of the panels and prevents the panel from rising out of the medium in its buoyant frozen state.