Heat pipe vacuum tubes

NARVA selected a construction for the heat pipe where no vent in the condenser was necessary. The temperature of the  NARVA heat pipe vacuum tube condenser does not exceed 160°C even when stagnant. As such, the device incorporates intrinsic safety features. the vaporizer fluid has been specially selected to ensure that not frost damage or fluid decomposition can occur over the 20 year product lifespan. Inside the heat pipe the pressure is max. 13 bar in stagnation.

 

• variable cut-off at 130 °C to 160 °C according to customer specification
• works in vertical position and up to an angle of 5° without loss of performance
• satisfies all requirements under DIN EN 12975-2
• designed for a lifetime of 20 years
• frost-proof

If the system is dimensioned towards maximum solar fraction, then a customer-specific temperature limit can be achieved via the intrinsically safe NARVA heat pipe.

Beschichtung Absorber: einseitig (Standard)	NARVA Vakuumröhre Heatpipe
Nennlänge LT (mm)	800                1.500                1.775                2.000
Rohrlänge (mm)	810                1.510                1.785                2.010
Durchmesser Glasrohr (mm)	56
Länge Anschlussrohr (mm)	30,5
Aperturfläche Glasrohr (m²)	0,0386          0,0750              0,090                0,1010
Rohr-Nennleistung (W) bei Einstrahlung von 1.000 W/m²	28                     56                      67                       76
gesammelte Wärme bei 1.000 kWh/a*m² Temperaturdifferenz 40 K (kWh/a)	25                     50                      60                       68
gesammelte Wärme bei 1.000 kWh/a*m² Temperaturdifferenz 1.000 K (kWh/a)	21                     42                      50                       57
Wärmedurchgangskoeffizient linear (W/m²K²)	1,12
Wärmedurchgangskoeffizient quadratisch (W / m²*K²)	0,004
Wirkungsgrad	0,750