Abstract: A method of forming a thermal energy storage unit for a surface to be cooled or heated includes using an additive manufacturing process to form a plurality of non-rectilinear structures having a plurality of thermally conductive substructures, the substructures defining a plurality of interior cavities within the substructures and a plurality of exterior fluid channels that cross over or under the plurality of interior cavities, arranging the plurality of non-rectilinear structures in a plurality of housings, wherein each of the plurality of non-rectilinear structures is arranged in a corresponding one of the plurality of housings, and connecting the plurality of housings to each other to build up the thermal energy storage unit whereby the thermal energy storage unit is modular.

Abstract: A thermal energy storage unit is arranged on a surface to be cooled or heated and includes a housing defining at least one flow path that extends along the surface, and at least one non-rectilinear structure that is arranged in the at least one flow path and has a plurality of substructures that are interconnected. The interconnected substructures define a plurality of exterior fluid channels external to the substructures and a plurality of interior cavities within the substructures. The exterior flow paths cross over or under the interior cavities. One of either the plurality of exterior fluid channels or the plurality of interior cavities is configured to contain a phase change material and the other of the plurality of exterior fluid channels and the plurality of interior cavities accommodates a heat transfer fluid that cross-flows the phase change material.