Basic Study on Flow Stabilization of Top-heat-type Thermosiphon

摘要

A top-heat-type thermosiphon utilizing vapor bubble pumping, which can realize heat transfer without anyexternal electric power, has been extensively studied. However, its application has some problems, one of whichis the unstable heat transfer, that is, intermittent circulation flow rate of the working fluid. This occurs under theconditions of less solar radiation during the morning and evening, and has been investigated by conducting a fieldexperiment using a model house. To overcome this problem, a thermosiphon control system has been proposed torealize stable heat transfer, that is, almost constant flow rate of the working fluid. In this study, a method forreducing the buffer chamber pressure is adopted to stabilize the flow rate. The control system comprises a bufferchamber, a solenoid valve, a pressure transducer, a vacuum pump with tank, and an embedded computer. Thepressure of the buffer chamber is ratcheted down to avoid violent boiling. In addition, the effectiveness of thesystem is demonstrated using the indoor experimental apparatus.