Specifications

dual-vacuum glass tube with transfer fluid sealed in the inner tube to transfer the heat energy absorbed by selective coating.

        Introduction

All-glass solar heat pipe is entirely made of borosilicate glass 3.3. In an all-glass solar heat pipe, the inner tube with transfer fluid sealed in is evacuated to form another vacuum beside the one between the outer and the inner tubes. This evacuated inner tube works as a copper pipe to transfer heat energy.

Working principle

The selective coating absorbs solar energy to heat up the transfer fluid that is sealed in the inner tube. The transfer fluid evaporates and the vapor rises up in sound velocity to the Condenser at the top of the tube, where it transfers heat energy to the water. The vapor condenses and flows back. This circulation will continue as long as there is solar energy.

Advantages

(1).Superior thermal conductivityIt can transfer much more heat energy even than silver, copper or aluminum which has very high heat conductivity.

(2).Superior isothermal stability: There is little pressure drop as well as temperature drop in the inner tube.

(3).The density of heat flow in the inner tube can be changed by modifying the heating surface of the condenser or the evaporation part.

(4). It can be used in both pressurized and unpressurized systems.

(5). Heat energy of the hot water in the tank will not lose through the condenser when the tube stops absorbing solar energy as there is a vacuum in the inner tube.

(6). The tube is anti-freezing for there is no water in the tube.

Specification

 

 

Specification
Structure	Two concentric borosilicate glass tubes
Material	Borosilicate glass 3.3
Outer tube diameter	Φ47±0.7mm  &=1.6mm
	Φ58±0.7mm  &=1.6mm
Inner tube diameter	Φ37±0.7mm  &=1.6mm
	Φ47±0.7mm  &=1.6mm
Length	47mm-1500mm
	58mm-1800mm
Coating	SS-ALNx/Cu
Solar absorption efficiency	0.90~0.95AM1.5
Launch ratio	0.04~0.06(80oC±5oC)
Vacuum degree	P≤5.0×10-3 (Pa)
Max stagnation temperature	260~300
Vacuum degree of inner tube	P≤1.0×10¯³ (Pa)
Average heat loss coefficient	ULT= 0.4~0.6w/(m2.oC)
Length of Condenser	&=125mm±5mm(Φ47-1500mm )
	&=145mm±5mm(Φ58-1800mm)
Resistance performance	Hail diameter≤ 25mm