A heat exchanger for cooling a plurality of heat-generating components with flat surfaces arranged in spaced parallel relation to one another has at least three flat, fluid-carrying panels, including a first end panel, a second end panel, and at least one middle panel. The middle panels have both of their opposed surfaces in thermal contact with a surface of a heat generating component. The end panels each have one surface in thermal contact with a surface of a heat-generating component. Inlet and outlet manifolds of the heat exchanger are in communication with the inlet and outlet openings of the middle panels. The inlet manifold communicates with the inlet opening of the first end panel, the outlet manifold communicates with the outlet opening of the second end panel, and the outlet opening of the first end panel communicates with the inlet opening of the second end panel.