Passive two phase heat transfer systems

A pool boiling apparatus comprising:

• a housing with a chamber;
• a heat transfer surface, comprising one or more protruding features which form channels in the chamber of the housing;
• and
• a first asymmetric diverter positioned over the heat transfer surface and extending at least partially across the one or more protruding features in the chamber and a passageway between the heat transfer surface and the asymmetric diverter, wherein the chamber of the housing is configured to form at one or more nucleation sites on the heat transfer surface one or more bubbles as a result of bubble nucleation creating a flow of the liquid on the heat transfer surface from which they have formed and wherein the first asymmetric diverter redirects the growth and path of the one or more bubbles preferentially in one direction as they form and grow so that the one or more bubbles push liquid out away from the growing one or more bubbles, wherein the one or more bubbles escape out of the passageway only out one side of the first asymmetric diverter causing liquid to flow into the passageway in the other side of the first asymmetric diverter, without an external pumping mechanism so as to improve heat transfer to the liquid and increase the critical heat flux limit.

A method for pool boiling, comprising:

• introducing a liquid into a chamber of a housing, wherein the chamber comprises a heat transfer surface, a first asymmetric diverter positioned over the heat transfer surface and a microgap between the heat transfer surface and the first asymmetric diverter;
• forming, at one or more nucleation sites on the heat transfer surface, one or more bubbles in the liquid on the surface of the chamber at the one or more bubble nucleation sites;
• and
• enhancing the flow of the liquid by redirecting with the first asymmetric diverter the growth and path of one of the one or more bubbles preferentially in one direction as they form and grow so that the one or more bubbles push liquid out away from the growing one or more bubbles, wherein the one or more bubbles escape out of the microgap only out one side of the first asymmetric diverter causing liquid to flow into the microgap in the other side of the first asymmetric diverter, wherein the liquid flow is caused without an external pumping mechanism and wherein the liquid flow improves heat transfer and increases the critical heat flux limit.