the pipe begins to vaporize and rapidly rises to the top of
the heat pipe while carrying a large amount of energy to
the manifold. As the heat is off-loaded to the manifold,
the vapor condenses and liquid returns to the bottom of
the heat pipe. An aluminum fin, held in the tube by a spring clip, facilitates heat transfer and mechanically supports the
heat pipe in place. A schematic configuration of the evacuated tube solar collectors is shown in Fig. 1.
This paper studies evacuated tube collectors, in particular, in the context of solar water heaters. A solar water heater system often needs a booster (storage unit) to provide
heat whenever litde or no solar energy is available. Efficient
development of such storage devices have been widely studied