A phase-change cooling system for a vehicle includes an electronic control device for receiving power from a power source and having a first temperature. The device utilizes a unibody construction wherein the flow conduit is constructed entirely from an insulative, non-conducting material without resorting to a metallic outer housing. An optical receiver connector can be a second distance from the first side wherein the first and the second distances are different and wherein the optical receiver connector is at a second position along the first edges. A secondary intake passage extends from the primary passage to communicate with the primary passage. Based on a specified multiplication value, one set of intermediate values is selected.