Post on 16-Jan-2023
Sun & Wind Energy 8/2011
Helmut Zangl, Managing Director of EuroSun Vacuum-Solar-Systems talks about its single-glass tubes at Intersolar. Photos (2): Wilhelm Breuer
OptimisedManufacturers of vacuum tube
collectors did not have much new to
put on show this year. Currently, the
focus is on improving the collectors’
appearance.
optics
87
Most of the vacuum tube collectors on the global market have double-walled glass tubes. The evacuated space between the
tubes insulates the absorber inside, the way a Thermos does. The tubes are produced in China. Chinese manufacturers have recently improved their absorber coatings. Along with the traditional alumini-um and aluminium nitride coatings, more and more tubes with additional coats of copper and stainless steel are on the market (see also article on page 80). European man ufacturers are increasingly using these tubes too (see table on page 90).
Kt Solar, the collector brand of Italy’s Turco Group S.r.l., also uses such tubes. The company has devel-oped a new collector series called the Sky Pro 1800. Kt formerly used 1,500 mm long tubes, but the Sky
Solar thermalVacuum tubeS
88
Solar thermal Vacuum tubeS
groundwater. In summer, groundwater cools the building. AMK built itself a generous headquarters. Along with 1,800 m2 of office space, the building has 2,500 m2 for storage and production. Initially, the company will lease a further 7,500 m2. If AMK grows as planned, in 10 years it will be using 10,000 m2 for production and storage.
Another new development at AMK is the SRCC test for its OWR collectors, which do not have CPC re-flectors. In addition, the company now offers collec-tors with black frames which blend in better with rooftops. Sales Manager Uwe Karl has announced the launch of a completely new collector for next year.
FK Solartechnik GmbH of Germany will also launch an improved vacuum tube collector next year. This
Sun & Wind Energy 8/2011
The new Sky Pro from Kt Solar is equipped with 1,800 m long tubes. Photo: Kt Solar
Pro is equipped with 1,800 mm tubes. This increases the stagnation temperature of the new design over its predecessor, the Sky CPC, from 249 to 259 °C.
Polish manufacturer Watt Sp. z.o.o. also offers something new. Last November, the company set up a new semi-automated line for vacuum tube CPC collectors.
In June, Switzerland’s AMK-Collectra AG moved from the town of Sevelen, near the Liechtenstein bor-der, to the town of Buchs, a few kilometres to the north. AMK’s building was built in accordance with the Swiss energy label Minergie. It has an active con-crete core combined with a heat pump, backed up by AMK collectors which extract thermal energy from
Sun & Wind Energy 8/2011
FK Solartechnik’s Sales Man-ager Michael Jaster explains the design of the heat pipes in the Solinas 3 collector. Photo: Jens-Peter Meyer
Hejia Solar covers its vacuum tubes with a glass plate. Photo: Jens-Peter Meyer
year, the company has added a feature to improve the visual appearance of the FK Solinas 3 heat pipe col-lector. A new cover fitted between adjacent collectors creates a uniform appearance when several collectors are connected to form a single field. Special insulat-ing elements for the interface between the collectors also reduce thermal losses. Like most manufacturers, FK Solartechnik uses mineral wool insulation in its collectors. What sets FK’s insulation apart, however, is a highly temperature-resistant pressed mineral wool with a 35 % better U-value than the insulation in a typical flat plate collector.
Chinese manufacturer Hejia Solar Energy Co., Ltd. also presented a new idea at Intersolar Europe. The vac-uum tubes in its collectors are placed behind a glass
Sun & Wind Energy 8/201190
Solar thermal Vacuum tubeS
Double glass tubes
Single glass tubes
Dies ist die Überschrift zu Tab in Datei:
st_jpm_Marktü_Vakuumr_double glass.xls
Manufacturer Product name Kind of tubes Number of tubes
Tube diameter [mm]
Tube length [mm]
Thickness inner tube [mm]
Thickness outer tube [mm]
Kind of glass τ [%]Absorption layer α [%] ε [%] Tube material
Manifold material
Manifold insulation
Thermal con-duction sheet
Reflector material
Testing norm μ0 1 a1 [W/m²·K] 1
a2 [W/m²·K²] 1
Stagnation temperature [°C]
Warranty[years]
Available in which countries
Calpak, Greece VTN U-type with CPC reflector
10 up to 16 47 1,500 1.6 1.6 borosilicate >90.1 3 layers >92.2 <7.5 copper copperglass wool and polyurethane
aluminium aluminium EN12975 3,4 0.665 0.700 0.036 227 10 worldwide
Camel Solar LTD, Macedonia
Vacuum ST-15
U-type without CPC reflector
10 / 15 58 1,800 1.7 1.7 borosilicate 91.5 3 layers95 up to 96
4 up to 5 copper aluminium rock wool aluminium - EN12975 6 n/a n/a n/a n/a 10 Serbia, Macedonia
Consolar, Germany
Tubo 12 CIU-type with CPC reflector
6 47 1,803 1.5 1.7 borosilicate 92 SC-coating93 up to 94
5 up to 6 Cu-Ni copper air aluminium aluminium EN12975 3 0.620 0.395 0.020 250 10 Europe
GREENoneTEC, Austria
VRK 10U-type with CPC reflector
10 / 14 47 1,520 1.6 1.6 borosilicate >91 Al-N 96 6 copper copper rock wool aluminium aluminium EN12975 3 0.605 0.85 0.01 286 5 worldwide
Hiramrut, IndiaSun-Ray water in glass 12 up to 37 47 1,800 1.6 1.6 borosilicate >92 Cu-S-Al n/a n/a glass n/a polyurethane - n/a MNRE 5 >0.45 1.760 2.120 200 15
IndiaSun-Ray water in glass 27 70 2,100 1.6 1.6 borosilicate >92 Cu-S-Al n/a n/a glass n/a polyurethane - n/a MNRE 5 >0.45 1.130 3.620 200 15
Huayang New Energy, China
hpheat pipe without CPC reflector
12 58 1,800 1.6 1.8 borosilicate 94 AL-SS-CO 94 n/a n/a n/a n/aaluminium alloy
rock wool EN12975 3,4,7 n/a n/a n/a 200 5 worldwide
Kt Solar, Italy Sky Pro 1800
U-type with reflector
10/12/14/16/18/20
58 1,800 1.6 1.7 borosilicate n/a AINx/Cu >94.5 <6.5 copper copper mineral wool n/a aluminium EN12975 3 0.718 1.051 0.004 259 10worldwide
Sky CPC 58U-type with reflector
8 /10/12/14/16/21
58 1,500 1.6 1.7 borosilicate n/a AINx/Cu >94.5 <6.5 copper copper mineral wool n/a aluminium EN12975 3 0.718 0.974 0.005 249 10
Ritter Solar, Germany
CPC 6/12/18 INOX
U-type with CPC reflector
6/12/18 47 1,500 1.6 1.6 borosilicate 91 AlN >94 < 6 stainless steelstainless steel /copper
rock wool aluminium aluminium EN12975 3,4 0.642 0.890 0.001 272 10worldwide
CPC 16/20 w INOX
U-type with CPC reflector
16/20 47 1,800 1.6 1.6 borosilicate 91 AlN >94 < 6 stainless steelstainless steel /copper
rock wool aluminium aluminium EN12975 3,4 0.644 0.749 0.005 301 10
Sunshore, China
Non pressure collector
water in glass 30 58 1,800 1.6 1.6 borosilicate ≥91 AlN/Al ≥86 ≤8 glass n/a polyurethane - aluminium EN12975 3 0.752 1.613 0.000 230 3 worldwide
Thermics, Italy 10 DTH-CPCcoaxial copper pipe with CPC reflector
10 58 1,800 1.6 2.2 borosilicate 91 Cr-AlN/Cu 95 5 copper aluminium rock wool aluminium aluminium EN12975 3 0.675 1.540 0.003 313 10 Europe
Unasol, Brazil 2AP30
heat pipe without CPC
30 58 1,800 1.8 1.6 borosilicate n/a AlN/Al >92 <8 copper aluminium glass wool aluminium - EN12975 3 0.687 1.505 0.011 245 10Brazil
AP20heat pipe without CPC
20 58 1,800 1.8 1.6 borosilicate n/a AlN/Al >93 <9 copper aluminium glass wool aluminium - EN12975 3 0.687 1.505 0.011 245 10
Vermos, Czech Republic
VU10-CPCU-type with CPC reflector
10 47 1,500 1.6 2.2 borosilicate 91 AINx/Cu 95 5 copper copper Armaflex copper aluminium n/a 0.650 1.210 0.011 210 8Europe
VU16-AU-type without reflector
16 47 1,500 1.6 2.2 borosilicate 91 AINx/Cu 95 5 copper copper Armaflex copper - n/a 0.810 1.840 0.009 210 8
Watt, Poland CPC 9 plus
U-type with CPC reflector
9 47 1,800 1.6 1.6 borosilicate 89 AlN 95.5 5.5 glass copper glass wool n/a aluminium EN12975 3 0.611 0.840 0.005 303 10Europe
CPC 15U-type with CPC reflector
15 47 1,800 1.6 1.6 borosilicate 89 AlN 95.5 5.5 glass copper glass wool n/a aluminium EN12975 3 0.573 1.240 0.006 304 5
Manufacturer Product name Kind of tubesNumber of tubes
Tube diam-eter [mm]
Tube length [mm]
Thickness tube [mm]
Kind of glass τ [%]Absorber sheet
Absorber layer α [%] ε [%]
Tube material
Tube absorber sheet connection
Material manifold
Manifold insulation
Tested for conformity with which standard/norm μ0 1 a1 [W/m²·K] 1
a2 [W/m²·K²] 1
Stagnation temperature [°C]
Warranty [years]
Available in which countries
3U Solar / EuroSun 5,
Germany
HP 65/30 heat pipe 20 / 30 65 1,980 2 borosilicate n/a copper tinox >95 <5 n/a ultrasoniccopper and aluminium
mineral wool EN12975 6 0.826 2 1.62 2 0.001 2 290 5Europe
DF 120/6 8 direct flow 6 120 2,950 3.5 borosilicate n/a copper tinox >95 <5 n/a ultrasoniccopper and aluminium
mineral wool EN12975 6 0.841 1.360 0.002 290 5
AkoTec, Germany
OEM Vario 3000
direct flow 30 56 2,000 1.8 soda lime 96 copper tinox 95 5 copper ultrasonic copper Armaflex/Kaiflex EN12975 3,4 0.749 1.485 0.002 192 10worldwide
OEM Vario 3000-30 hp
heat pipe 30 56 2,000 1.8 soda lime 96 copper tinox 95 5 copper ultrasonic copper Armaflex/Kaiflex EN12975 3,4 0.683 1.489 0.000 160 10
Elco, GermanyAuron DF 15 / Auron DF 20
direct flow 15 / 20 70 1,790 n/a borosilicate n/a aluminiumhighly selective
n/a n/a copper clamp ring copper rock wool EN12975 3 0.821 10 2.824 10 0.0047 10 206 5 Europe
Hewalex, PolandKSR10 / 2xKSR10
direct flow 10 / 20 56 2,000 1.8 borosilicate 96 copper tinox 95 4 copperultrasonic welding
brass rock wool EN12975 3 0.78 1.27 0.0012 303 5 Europe
Kingspan Renewables, Northern Ireland
HP250 heat pipe 30 65 1,960 1.5 soda lime 92 copper tinox 95 5 copper ultrasonic copper melamine foam EN12975 3 0.755 1.060 0.008 217 20 9 worldwide
Varisol direct flow 1 up to 150 7 65 1,950 1.5 soda lime 92 copper tinox 95 5 copper ultrasonic PPS n/a EN12975 3 0.783 1.061 0.023 240 20 9worldwide except US
Sunda, ChinaSeido1-16AS heat pipe 8/16 100 2,000 2.8 borosilicate >90 aluminium
selective coating
>92 <8 copper pressed copper polyurethane EN12975 3 0.694 2.118 0.004 235 5worldwide
Seido2-16 direct flow 8/16 100 2,000 2.8 borosilicate >90 aluminiumselective coating
>92 <8 copper pressed copper polyurethane EN12975 3,4 0.798 0.994 0.010 276 5
1 relating to aperture, 2 manufactured under Apricus license; 3 Solar Keymark labeled; 4 SRCC labeled; 5 MNRE labeled; 6 Solar Keymark certification is in progress; 7 Golden Sun labels
1 relating to aperture, 2 data for 30 tube collectors; 3 Solar Keymark labeled; 4 SRCC labeled; 5 EuroSun is part of the 3U Group ; 6 Solar Keymark certification is in progress; 7 number of tubes is variable; 8 also tubes with 100 mm diameter available; 9 conditions apply; 10 data for 20 tube collectors
Sun & Wind Energy 8/2011 91
Source: company data
Manufacturer Product name Kind of tubes Number of tubes
Tube diameter [mm]
Tube length [mm]
Thickness inner tube [mm]
Thickness outer tube [mm]
Kind of glass τ [%]Absorption layer α [%] ε [%] Tube material
Manifold material
Manifold insulation
Thermal con-duction sheet
Reflector material
Testing norm μ0 1 a1 [W/m²·K] 1
a2 [W/m²·K²] 1
Stagnation temperature [°C]
Warranty[years]
Available in which countries
Calpak, Greece VTN U-type with CPC reflector
10 up to 16 47 1,500 1.6 1.6 borosilicate >90.1 3 layers >92.2 <7.5 copper copperglass wool and polyurethane
aluminium aluminium EN12975 3,4 0.665 0.700 0.036 227 10 worldwide
Camel Solar LTD, Macedonia
Vacuum ST-15
U-type without CPC reflector
10 / 15 58 1,800 1.7 1.7 borosilicate 91.5 3 layers95 up to 96
4 up to 5 copper aluminium rock wool aluminium - EN12975 6 n/a n/a n/a n/a 10 Serbia, Macedonia
Consolar, Germany
Tubo 12 CIU-type with CPC reflector
6 47 1,803 1.5 1.7 borosilicate 92 SC-coating93 up to 94
5 up to 6 Cu-Ni copper air aluminium aluminium EN12975 3 0.620 0.395 0.020 250 10 Europe
GREENoneTEC, Austria
VRK 10U-type with CPC reflector
10 / 14 47 1,520 1.6 1.6 borosilicate >91 Al-N 96 6 copper copper rock wool aluminium aluminium EN12975 3 0.605 0.85 0.01 286 5 worldwide
Hiramrut, IndiaSun-Ray water in glass 12 up to 37 47 1,800 1.6 1.6 borosilicate >92 Cu-S-Al n/a n/a glass n/a polyurethane - n/a MNRE 5 >0.45 1.760 2.120 200 15
IndiaSun-Ray water in glass 27 70 2,100 1.6 1.6 borosilicate >92 Cu-S-Al n/a n/a glass n/a polyurethane - n/a MNRE 5 >0.45 1.130 3.620 200 15
Huayang New Energy, China
hpheat pipe without CPC reflector
12 58 1,800 1.6 1.8 borosilicate 94 AL-SS-CO 94 n/a n/a n/a n/aaluminium alloy
rock wool EN12975 3,4,7 n/a n/a n/a 200 5 worldwide
Kt Solar, Italy Sky Pro 1800
U-type with reflector
10/12/14/16/18/20
58 1,800 1.6 1.7 borosilicate n/a AINx/Cu >94.5 <6.5 copper copper mineral wool n/a aluminium EN12975 3 0.718 1.051 0.004 259 10worldwide
Sky CPC 58U-type with reflector
8 /10/12/14/16/21
58 1,500 1.6 1.7 borosilicate n/a AINx/Cu >94.5 <6.5 copper copper mineral wool n/a aluminium EN12975 3 0.718 0.974 0.005 249 10
Ritter Solar, Germany
CPC 6/12/18 INOX
U-type with CPC reflector
6/12/18 47 1,500 1.6 1.6 borosilicate 91 AlN >94 < 6 stainless steelstainless steel /copper
rock wool aluminium aluminium EN12975 3,4 0.642 0.890 0.001 272 10worldwide
CPC 16/20 w INOX
U-type with CPC reflector
16/20 47 1,800 1.6 1.6 borosilicate 91 AlN >94 < 6 stainless steelstainless steel /copper
rock wool aluminium aluminium EN12975 3,4 0.644 0.749 0.005 301 10
Sunshore, China
Non pressure collector
water in glass 30 58 1,800 1.6 1.6 borosilicate ≥91 AlN/Al ≥86 ≤8 glass n/a polyurethane - aluminium EN12975 3 0.752 1.613 0.000 230 3 worldwide
Thermics, Italy 10 DTH-CPCcoaxial copper pipe with CPC reflector
10 58 1,800 1.6 2.2 borosilicate 91 Cr-AlN/Cu 95 5 copper aluminium rock wool aluminium aluminium EN12975 3 0.675 1.540 0.003 313 10 Europe
Unasol, Brazil 2AP30
heat pipe without CPC
30 58 1,800 1.8 1.6 borosilicate n/a AlN/Al >92 <8 copper aluminium glass wool aluminium - EN12975 3 0.687 1.505 0.011 245 10Brazil
AP20heat pipe without CPC
20 58 1,800 1.8 1.6 borosilicate n/a AlN/Al >93 <9 copper aluminium glass wool aluminium - EN12975 3 0.687 1.505 0.011 245 10
Vermos, Czech Republic
VU10-CPCU-type with CPC reflector
10 47 1,500 1.6 2.2 borosilicate 91 AINx/Cu 95 5 copper copper Armaflex copper aluminium n/a 0.650 1.210 0.011 210 8Europe
VU16-AU-type without reflector
16 47 1,500 1.6 2.2 borosilicate 91 AINx/Cu 95 5 copper copper Armaflex copper - n/a 0.810 1.840 0.009 210 8
Watt, Poland CPC 9 plus
U-type with CPC reflector
9 47 1,800 1.6 1.6 borosilicate 89 AlN 95.5 5.5 glass copper glass wool n/a aluminium EN12975 3 0.611 0.840 0.005 303 10Europe
CPC 15U-type with CPC reflector
15 47 1,800 1.6 1.6 borosilicate 89 AlN 95.5 5.5 glass copper glass wool n/a aluminium EN12975 3 0.573 1.240 0.006 304 5
Manufacturer Product name Kind of tubesNumber of tubes
Tube diam-eter [mm]
Tube length [mm]
Thickness tube [mm]
Kind of glass τ [%]Absorber sheet
Absorber layer α [%] ε [%]
Tube material
Tube absorber sheet connection
Material manifold
Manifold insulation
Tested for conformity with which standard/norm μ0 1 a1 [W/m²·K] 1
a2 [W/m²·K²] 1
Stagnation temperature [°C]
Warranty [years]
Available in which countries
3U Solar / EuroSun 5,
Germany
HP 65/30 heat pipe 20 / 30 65 1,980 2 borosilicate n/a copper tinox >95 <5 n/a ultrasoniccopper and aluminium
mineral wool EN12975 6 0.826 2 1.62 2 0.001 2 290 5Europe
DF 120/6 8 direct flow 6 120 2,950 3.5 borosilicate n/a copper tinox >95 <5 n/a ultrasoniccopper and aluminium
mineral wool EN12975 6 0.841 1.360 0.002 290 5
AkoTec, Germany
OEM Vario 3000
direct flow 30 56 2,000 1.8 soda lime 96 copper tinox 95 5 copper ultrasonic copper Armaflex/Kaiflex EN12975 3,4 0.749 1.485 0.002 192 10worldwide
OEM Vario 3000-30 hp
heat pipe 30 56 2,000 1.8 soda lime 96 copper tinox 95 5 copper ultrasonic copper Armaflex/Kaiflex EN12975 3,4 0.683 1.489 0.000 160 10
Elco, GermanyAuron DF 15 / Auron DF 20
direct flow 15 / 20 70 1,790 n/a borosilicate n/a aluminiumhighly selective
n/a n/a copper clamp ring copper rock wool EN12975 3 0.821 10 2.824 10 0.0047 10 206 5 Europe
Hewalex, PolandKSR10 / 2xKSR10
direct flow 10 / 20 56 2,000 1.8 borosilicate 96 copper tinox 95 4 copperultrasonic welding
brass rock wool EN12975 3 0.78 1.27 0.0012 303 5 Europe
Kingspan Renewables, Northern Ireland
HP250 heat pipe 30 65 1,960 1.5 soda lime 92 copper tinox 95 5 copper ultrasonic copper melamine foam EN12975 3 0.755 1.060 0.008 217 20 9 worldwide
Varisol direct flow 1 up to 150 7 65 1,950 1.5 soda lime 92 copper tinox 95 5 copper ultrasonic PPS n/a EN12975 3 0.783 1.061 0.023 240 20 9worldwide except US
Sunda, ChinaSeido1-16AS heat pipe 8/16 100 2,000 2.8 borosilicate >90 aluminium
selective coating
>92 <8 copper pressed copper polyurethane EN12975 3 0.694 2.118 0.004 235 5worldwide
Seido2-16 direct flow 8/16 100 2,000 2.8 borosilicate >90 aluminiumselective coating
>92 <8 copper pressed copper polyurethane EN12975 3,4 0.798 0.994 0.010 276 5
1 relating to aperture, 2 manufactured under Apricus license; 3 Solar Keymark labeled; 4 SRCC labeled; 5 MNRE labeled; 6 Solar Keymark certification is in progress; 7 Golden Sun labels
Vacuum tubeS
The roof-integrated collector from AkoTec also takes advantage of reflected light striking the back side of the absorber.
Sun & Wind Energy 8/2011
cover. The company did not reveal how it intends to ap-ply this system, but one possible use could be on the façades of tall buildings, where a cover could offer in-creased protection against high winds.
Wind resistant: flat roof installation for harsh conditions
There are also some new developments in single glass tube collectors. In these tubes, the absorber is inside of a single-walled vacuum tube. Such tubes therefore require a glass-metal transition.
Germany’s AkoTec has developed a roof-integrat-ed version of its vacuum tube collector. An aluminium sheet behind the tubes stands in for roof tiles, en-abling the collectors to be installed in the same plane as the roofing and ensuring harmonious integration of the collectors into the roof. Collectors with a back wall are already part of AkoTec’s product range. This is due to a unique characteristic of the Narva tubes used by AkoTec: their absorbers can be coated on both sides. This enables the vacuum tubes to absorb sunlight on their back sides as well. The back wall of the AkoTec roof-integrated collectors also contributes to this ef-
Sun & Wind Energy 8/2011 93
The direct flow, single-glass collector Varisol presented last year by Kingspan is made of individually assembled tubes on the roof only. Photo: Kingspan
fect. According to Sales Manager Katrin Müller, mea-surement data shows that the collectors are capable of up to 20 % greater yield.
Another innovation from AkoTec is an installation system for flat roofs optimised for high winds. Lateral spoilers ensure that the collector is pressed down on-to the flat roof in high winds. This eliminates the need for weights to keep collectors in place on the roof. This is important, of course, in locations subject to high winds, such as buildings more than 25 m high.
Jens-Peter Meyer
Further information:3U Solar Systemhandel AG : www.3usolar.de AkoTec Produktionsgesellschaft mbH: www.akotec.euAMK Collectra AG: www.amk-collectra.ch
Market leader in Europe.
Industrially manufacturedtop quality products.
Distribution exclusively to OEM partners.
www.ritter-gruppe.com
Ritter Energie- und Umwelttechnik GmbH & Co. KGKuchenäcker 2 · 72135 Dettenhausen · GermanyTel. +49 7157 5359 1200 · info@ritter-gruppe.com
Leading manufacturer ofevacuated tube collectors
Beijing Sunda Solar Energy Technology Co., Ltd.: www.sundasolar.comCalpak-Cicero Hellas S.A.: www.calpak.grCamel Solar LTD: v_ristov@hotmail.com (website in construction)Consolar Solare Energiesysteme GmbH: www.consolar.deElco (Ariston Thermo S.p.A. ): www.elco.netEuroSun Vacuum-Solar-Systems GmbH: www.euro-sun-solar.deFK Solartechnik GmbH: www.fksolar.deGREENoneTEC Solarindustrie GmbH: www.greenonetec.comHejia Solar Energy Co., Ltd.: www.hjsolar.comHewalex: www.hewalex.plHiramrut Energies Pvt.Ltd: www.sunray.co.inKingspan Renewables Ltd.: www.kingspansolar.comKt Solar (Turco Group S.r.l.): www.ktsolar.comRitter Energie- und Umwelttechnik GmbH & Co. KG: www.ritter-gruppe.comSunshore Solar Energy Co.,Ltd :www.sunshore.cnThermics srl: www.thermics.itUnasol: www.unasol.com.brVermos s.r.o.: www.vermos.czWatt Sp. z o.o.: www.watt.pl