Abstract
A new type of heat pipe, called BACH (Bubble-Actuated Circulating Heat pipe), was revised so as to be capable of both top-heat mode and bottom-heat mode by valve switching. In this research, heat transport characteristics of the BACH between underground and ground surface were measured experimentally. The working fluid was R134a. The obtained results show that at bottom-heat mode, BACH can transport heat of 200W maximum, while it can transport heat of 300W maximum at top-heat mode. The heat transport characteristics were affected by underground length and cooling method of intermediate cooled section, and in general the underground length 4m was optimal.
