The aluminum flat heat pipe using cyclopentane as working fluid

Aluminum flat heat pipes are expected to be very useful for electronic components cooling because thin, light and bendable pipes are possible. However, there is a problem that conventional working fluids, such as freons (including not only CFCs but also HCFCs and HFCs), are harmful to the global environment. In this paper, cyclopentane application to aluminum heat pipes is discussed. First, thermal resistance in aluminum-cyclopentane heat pipes was evaluated as compared with aluminum-HCFC123 heat pipes. Secondary, the long time reliability in aluminum-cyclopentane heat pipes was compared with that of aluminum-HCFC123. These evaluations showed the possibility of substitution for HCFC123 by cyclopentane and gave one answer to the working fluid problem in aluminum heat pipes.