A heat-exchange apparatus and a mounting component set for installation into storage tanks. The heat-exchange apparatus comprises a heat-exchanging component, a coupling manifold configured to engage with the heat-exchanging component, and a hollow, elongate, flow-directing element that delivers fluid to the heat-exchanging component. The mounting component set comprises an inner flange for engaging the inner wall of the storage tank, an outer flange for engaging the outer wall of the storage tank, and at least one gasket cooperable with one of the flanges. The heat-exchange apparatus sealably engages the outer flange such that the heat-exchanging component extends into the interior of the tank, and the coupling manifold is interconnectable to an external supply of heat-exchange fluid.