Abstract

A cooling system for passively cooling an enclosure incorporating at least one inclined heat pipe having an evaporator side extending within the enclosure and a condenser side extending outside the enclosure in contact with the ambient environment. A thermal storage device within the enclosure is configured having a first portion extending adjacent the evaporator side of the heat pipe and a second portion extending within, and generally concentric with, the evaporator side of the heat pipe. A solid-to-liquid phase change material is sealed within this thermal storage device such that this material changes to a liquid upon the absorption of heat. To further enhance the transfer of heat from within the enclosure to outside the enclosure, a series of fins can be added to the first portion of the thermal storage device as well as to the condenser side of the heat pipe. Additionally, a series of internal fins can be mounted to the second portion of the thermal storage device which would preferably be submerged in the working fluid contained within the evaporator side of the heat pipe.