Vitosol 300 Vacuum Tube Collector Based On The Heat Pipe Principle - Viessmann Vitosol
100 Technical Manual

Vitosol 300 vacuum tube collector based on the heat pipe principle

A Evacuated glass tube
B Heat pipe
C Absorber
E
E Dual−pipe heat exchanger
F Connection pipe
G Thermal insulation
VITOSOL
D Condenser
E Dual−pipe heat exchanger
G F H K
H Retaining clip
K Connection housing
L Diverter
2.1 Construction and function of the collectors
The tube shape gives the collector great
stability.
Re−evacuation of the tubes is not
necessary as the tubes have a permanent
airtight seal.
The vacuum in the glass tubes ensures
optimum heat insulation. Convection
losses between the glass tube and the
absorber are almost completely
eliminated. This enables the utilisation of
even low radiation levels (diffused
radiation).
Built into each vacuum tube is a
Sol−Titanium coated copper absorber.
This ensures high absorption of solar
radiation and low emission of thermal
radiation.
A heat pipe filled with an evaporator
liquid is arranged on the absorber. The
heat pipe is connected to the condenser
via a flexible coupling. The condenser is
fitted inside a dual−pipe heat exchanger.
This involves a so−called dry connection,
i.e. the tubes can be rotated or replaced
even when the installation is filled and
under pressure.
Heat is transferred from the absorber to
the heat pipe. This lets the liquid
evaporate. The vapour then rises to the
condenser.
Note
The angle of inclination must be at least
25º to guarantee circulation of the
evaporator liquid inside the heat
exchanger.
The heat is transferred to the passing
process medium by the double−pipe heat
exchanger containing the condenser; this
causes the vapour to condense. The
condensate returns into the heat pipe and
the process is repeated.
Absorber surface areas of up to 6 m
L
be joined to form a single collector array.
For this purpose, the standard delivery
includes flexible connection pipes, sealed
with O−rings.
A connection kit with clamping ring
fittings enables the collector array to be
quickly connected to the pipes of the
solar circuit.
The collector temperature sensor is
installed in a sensor mounting on the
flow pipe in the collector connection
housing.
Vitosol 300
2
can
13