The RS-UVAC 70-7G is based on the RS-UVAC 6G technology, which is an advanced technologically tubular heat collecting element (“HCE”) for Concentrated Solar Power plants (CSP) based on Parabolic Trough technology, and uses synthetic thermal oil as heat transfer fluid (HTF).
The RS-UVAC 70-7G is the 7th generation of vacuum tubes that has been developed by Rioglass based on more than 20 years of proven track record of developing HCEs for the solar thermal industry by Solel.
The RS-UVAC tubes are built and tested for extreme environmental conditions and complies with strict standards and quality for Power Piping as well as for Boiler & Pressure vessel (e.g.: ASME B31.1, ASME VIII)
UVAC 70-7G benefits at a glance:

  • Extremely high solar absorption
  • Reduced heat losses
  • Larger active area
  • Increased thermal heat production
  • No fluorescent phenomena
  • Long-term hydrogen prevention
  • Based on over 20-years of field-proven experience


Rioglass’s UVAC 70-7G is a technologically advanced tubular heat collecting element (HCE) for concentrated solar power plants (CSP) based on parabolic trough technology, which uses synthetic thermal oil as heat transfer fluid (HTF).

The UVAC 70-7G is the sixth generation of vacuum tubes developed by Rioglass. Our technology is based on a proven track record including over 20 years of experience developing HCE’s for the solar thermal industry.

All of our UVAC tubes are built and tested to withstand extreme environmental conditions and comply with strict quality standards for Power Piping as well as for Boiler & Pressure vessels (e.g., ASME B31.1 and ASME VIII).

Stainless steel tube

  • Length: 4,061mm, ± 1mm
  • Outer diameter: 70mm, ± 0.3mm
  • Wall thickness: 2mm, ± 0.2mm
  • Selective coating at THTF (HTF temperature): 20℃
  • Coating technique: Sputtered, Selective
  • Average solar absorptance by spectrophotometer after annealing (according to ASTM G173): α ≥ 96.2%
  • Emissivity Factor (by FTIR): ε≤ 9.5% at temperature 400℃

Glass tube

  • Outer diameter (Borosilicate A.R.): 115mm, ±1.8mm
  • Wall thickness: 3mm, ±0.5mm
  • Mean solar transmittance along 100% of the glass envelope (Air Mass 1.5 according to ASTM G173): τ ≥ 96.7%
  • Active area (bellow shadowing) at THTF of 350℃: ≥ 96.4% of bulk length
  • Number of bellow convolutions: 3
  • Net weight (without HTF): 23 kg
  • Maximum absolute design pressure (at 350˚C): 40 bar
  • Vacuum pressure: 10-4 mbar
  • Getter Hydrogen absorber: Designed for 25 years product lifetime
  • Designed for maximum HTF temperature of 400°C (450°C for 10% of the accumulative operation time)

Contact us today to learn more about the Rioglass UVAC 7G and our other products.

The UVAC 70-7G Components:

  1. Coated Stainless Steel Absorber tube
  2. Coated Glass Sleeve Enclosure
  3. Glass to metal Joints
  4. Bellows
  5. Getter & Barium Getters
  6. External shields
  7. Internal shield