Self-driven chemical heat pipe

A method and apparatus for a self-driven chemical heat pipe are provided in a circuit including an endothermic reaction chamber and an exothermic chamber connected by a pair of arms extending therebetween. Reactant is endothermically reacted near the heat source to create reaction product at a pressure greater than exists at the exothermic reaction chamber to promote flow thereof through one of the arms. Reaction product is exothermically reacted in the exothermic reaction chamber near the heat sink to liberate heat and form recombined gaseous reactant. That gaseous reactant is converted to liquid form, which liquid-form reactant occludes part of the other arm and flows therethrough toward the endothermic chamber to complete the cycle. The liquid occlusion of that arm ensures adequate unidirectional flow about the circuit. Provision may be made for selectively reversibly storing reaction product or reactant to accommodate differences in time between heat production at the source and heat demand at the sink.