Basic Study on Flow Stabilization of Top-Heat-Type Thermosiphon
Abstract
A top-heat-type thermosiphon utilizing vapor bubble pumping, which can realize heat transfer without any external electric power, has been extensively studied. However, its application has some problems, one of which is the unstable heat transfer, that is, intermittent circulation flow rate of the working fluid. This occurs under the conditions of less solar radiation during the morning and evening, and has been investigated by conducting a field experiment using a model house. To overcome this problem, a thermosiphon control system has been proposed to realize stable heat transfer, that is, almost constant flow rate of the working fluid. In this study, a method for reducing the buffer chamber pressure is adopted to stabilize the flow rate. The control system comprises a buffer chamber, a solenoid valve, a pressure transducer, a vacuum pump with tank, and an embedded computer. The pressure of the buffer chamber is ratcheted down to avoid violent boiling. In addition, the effectiveness of the system is demonstrated using the indoor experimental apparatus.