The invention provides for an orientation insensitive heat exchanger assembly for cooling an electronic device comprising a hermetically sealed housing defining a boiling chamber and two condensing chambers. A partition is disposed in the boiling chamber and defines two sets of alternating channels extending in overlapping relationship to one another and with one set of alternating channels open to one of the condensing chambers and the other set of alternating channels open to the other condensing chamber for sealing the condensing chambers from one another. Coolant is maintained in each of the condensing chambers. In operation, if the thermosiphon is tilted with one side lower than the other, the channels open to the lower side are empty of coolant into the lower condensing chamber while the channels open to the opposite upper side hold the coolant over the entire boiling chamber aligning with an electronic device to continue cooling.