NARVA Lichtquellen GmbH + Co. KG

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last updated / print date: 23.11.2017
direct flow vacuum tubes | NARVA Lichtquellen GmbH + Co. KG | Light can do more.
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NARVA Lichtquellen GmbH + Co. KG, Industriegebiet Nord, Erzstraße 22, D-09618 Brand-Erbisdorf
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direct flow vacuum tubes

  • usable in continuous operation due to their flat caracteristic line, up to the heat transfer temperature of 150 °C
  • fulfil all requirements under DIN EN 12975-2
  • designed for a lifetime of 20 years
  • stagnation temperature: up to 300 °C
  • if there is a risk of frost a corresponding heat transfer substance is to be used


If the heat requirements of the process are always higher than the maximum output ofn the solar collectors, the system benefits from the high degree of efficiency of the direct flow NARVA vacuum tubes.
 
 
 
 

Ordering data - direct flow vacuum tubes

 Absorber
coating
 
Length
mm
 connection
 length mm
PUOrder no.
VR 1775 Standard          one side  1.775                 57   10   1301 0016
                               
VR 2000 Standard          one side  2.000                 57   10   1301 0006
                               
VR 1775 Power        both sides  1.775                 57   10   1301 0017
                             
VR 2000 Power        both sides  2.000                 57   10   1301 0005
                            

 

 
 
 
 
 

technical data - direct flow vacuum tubes

Absorber coating: one side (standard)NARVA vacuum tubes
direct flow
nominal length LT (mm)      1.775          2.000
 
tube length (mm)      1.785          2.010
diameter of glass tube (mm)     56
diameter of connecting tube (mm)     57
apertureface of glass tube (m²)        0,090         0,1010
nominal tube output (W)
at an irradiance of 1,000 W/m²
          71              80
absorbed heat at 1,000 kWh/a*m²
temperature difference 40K (kWh/a)
          64              72
absorbed heat at 1,000 kWh/a*m²
temoerature difference 100 K (kWh/a)
          54               61
heat transmission coeffizient linear (W / m²*K²)      1,12
heat transmission coefficient linear (W / m²*K²)        0,004
efficiency factor        0,781