HCE Tubes

Linear Absorber Tubes / Heat Collecting Elements

Linear Absorber Tubes or Heat Collecting Elements (HCEs), also simply referred to as Receivers, are used to absorb the concentrated sunlight from the Parabolic Trough [insert link to page with information about PT] collector or the Compact Linear Fresnel [insert link to page with information about CLFR]collector, and transfer the energy absorbed into a Heat Transfer Fluid (HFT) that is pumped through the HCEs. This energy in the form of heat, will elsewhere be used or converted into electricity. Rioglass Solar´s product line uses the registered brand name PTR®, which is the abbreviation for Parabolic Trough Receiver. In the picture below you can distinguish the main elements that form the HCE. Rioglass Solar offer its PTR® product line in different product variations:

Diameter steel tube: PTR® 70, PTR® 80, and PTR® 90 mm

Length steel tube: 4.060 mm (PTR® 70 and PTR® 90) and 4.386 mm (PTR® 80)

Different max. T: 4G for standard HTF or other generations for high temperature Applications

Please contact us for more information.

Assembly

• length: 4386 mm ± 2,0 mm at 20°C ambient temperature

• effective aperture length: ≥ 96.7 % of the bulk length at 350°C working temperature

Absorber

• outer diameter: 80,0 mm + 0,30 / – 0,30 mm

• wall thickness: 2,0 mm + 0,2 / – 0,2 mm

• steel-type: EN1.4541 or AISI321

• average solar absorptance of all receivers delivered: α ≥ 0,955 (95,5%) 2) ASTM

• absorptance of single absorber: αASTM ≥ 0,9452)

• average thermal emittance of all receivers delivered (400°C): ε ≤ 0.0953) (9,5%)

• emittance of single absorber (400°C): ε ≤ 0.123)

Glass Envelope

• borosilicate glass 4)

• outer diameter: 136 mm ± 3.0 mm

• antireflective coating on ≥ 95,0% of aperture length

• average solar transmittance of coated area of all receivers delivered: τ ≥ 0.9652) (96,5 %)

• transmittance of single glass envelope in coated area: τ ≥ 0,960 2) (96,0 %)

Weight

• 31 kg +3,0 kg / -3,0 kg (unfilled)

Vacum

• initial residual gas pressure ≤ 10-4 mbar

Average values only valid for operation with Rioglass shields

• mean heat loss values corresponding to emittance = 9.5%

• heat loss single values may vary due to deviation of emittance data’s

Heat transfer fluid (HTF)

non-corrosive thermal oil with an effective partial pressure of dissolved hydrogen of pH2 < 30 Pa 5)

Recomended wellding filler material

DIN1.4316 or DIN1.4551

Maximum Operating Temperature

Maximum bulk fluid temperature: 400 ºC

Flow rate

Reynolds number Re > 20.000

Operating pressure

≤ 37 barg

Operating conditions

Solar concentration ratio: C < 100

Environmental conditions

• Min / max temperature ambient: -10ºC / +50ºC

• Max. relative humidity: 95%

• Max. design wind speed: 40 m/s

• Max. base wind speed: 30 m/s – wind class 3

• Max. equivalent acceleration 0,4 g in case of seism

• Compliance with maximum C2 corrosivity class conditions according to ISO9223

Design and manufacturing codes

The RIOGLASS PTR®80-4G receivers are designed, manufactured and inspected in compliance to the following regulations

• Pressure Equipment Directive 2014/68/UE of the European Parliament

• ASME Sec. VIII Div. 1

Further requirements included in referred standards such as EN10217-7, A249, etc. are considered with the RIOGLASS PTR®80-4G receiver.

Standards for power or process piping (ASME B31.1 or ASME B31.3) are not designated for the RIOGLASS PTR®80-4G solar receiver as a component of pressure vessel. However, by following the requirements of ASME Sec. VIII Div. 1, RIOGLASS PTR®80-4G receivers fulfil also applicable requirements of ASME B31.1 and ASME B31.3.

Assembly

• length: 4.060 mm ± 2,0 mm at 20°C ambient temperature

• effective aperture length: ≥ 96.7 % of the bulk length at 350°C working temperature 1)

Absorber

• outer diameter: 88,9 mm + 0,15 / – 0,35 mm

• wall thickness: 2,5 mm + 0,25 / – 0,25 mm

• steel-type: DIN 1.4541 or similar

• average solar absorptance of all receivers delivered: αISO ≥ 0,957 (95,5%) 2) | αASMT ≥ 0,960 (95,5%) 3)

• absorptance of single absorber: αISO ≥ 0,945 2)

• average thermal emittance of all receivers delivered (400°C / 752ºF): ε ≤ 0.095) (9,5%) 4)

• emittance of single absorber (400°C): ε ≤ 0.105 4)

Glass envelope

• borosilicate glass 5)

• outer diameter: 142 mm ± 2.5 mm

• antireflective coating on ≥ 95,0% of aperture length

• average solar transmittance of coated area of all receivers delivered: τ ≥ 0.970) (97 %) 2)

• transmittance of single glass envelope in coated area: τ ≥ 0,960 2) (96,0 %) 2)

Weight

• 35 kg ± 10% (unfilled)

Vacum

• initial residual gas pressure ≤ 10-4 mbar