A new TRNSYS collector model for evacuated tubular collectors with tubular absorbers is developed. Traditional flat plate collector performance equations have been integrated over the whole absorber circumference. On each tube the model determines the size and position of the shadows caused by the neighbor tube. An all glass tubular collector with tubular absorbers with 14 tubes connected in parallel is investigated theoretically with the model and experimentally in an outdoor collector test facility. Performance calculations with the new model are compared with measured results and a good degree of similarity between the measured and calculated results is found. Further, it is illustrated how the model can be used for geometrical parameter studies both for constant collector mean fluid temperatures and for varying temperature conditions in a solar heating plant. These investigations are performed for two climates: Copenhagen (Denmark) and Uummannaq (Greenland).

1.
Weiss
,
W.
,
Bergmann
,
I.
,
Faninger
,
G.
, 2004, “
Solar Heating Worldwide. Markets and Contributions to the Energy Supply 2001
.” IEA Solar Heating & Cooling Programme, Feb.
2.
Barrett
,
A. L.
et al.
, 1988, “
Thermal Modelling of Evacuated Tubular Solar Collectors
,” Solar 88,
Proceedings of the 1988 annual meeting of the American Solar Energy Society
, pp
505
510
.
3.
Qin
,
L.
, and
Furbo
,
S.
, 1999, “
Evaluation of Evacuated Tubular Solar Collectors for Large SDHW Systems and Combined Space Heating Systems
,”
Proceedings of NorthSun99, 11–14 August, 1999
,
Edmonton
,
Alberta
, Canada.
4.
Perez
et al.
, 1995, “
Calculating Solar Radiation Received by Tubular Solar Energy Collectors
,”
Sol. Engineering
0038-092X,
I
, pp.
699
704
.
5.
Lart
,
S.
, 2000, “
Development of a Thermal Performance Test for an Integrated Collector-Storage Solar Water Heating System
,” Ph.D. thesis, Division of Mechanical Engineering and Energy Studies, University of Wales Cardiff, pp.
90
100
.
6.
Shah
,
L. J.
, and
Furbo
,
S.
, 2004, “
Vertical Evacuated Tubular Collectors Utilizing Solar Radiation from All Directions
,”
Appl. Energy
0306-2619,
78/4
pp
371
395
.
7.
Klein
,
S. A.
et al.
, 1996, TRNSYS 14.2, User Manual, University of Wisconsin Solar Energy Laboratory.
8.
Shah
,
L. J.
, and
Furbo
,
S.
, 2003, “
Thermal Performance of Evacuated Tubular Collectors Utilizing Solar Radiation from all Directions
,”
Proceedings, ISES World Sun Congress
,
Gothenburg
.
9.
Solar Energy. The State of the Art
, ISES Position Papers, 2001,
Gordon
,
J.
, ed.,
James & James
, London.
10.
Pyrko
,
J.
, 1984, “
A Model of the Average Solar Radiation for the Tubular Collector
,”
Int. J. Sol. Energy
0142-5919,
32
, pp.
563
565
.
11.
Duffie
,
J. A.
, and
Beckman
,
W. A.
, 1991,
Solar Engineering of Thermal Processes
,
2nd ed.
,
Wiley Interscience
, New York.
12.
Incropera
,
F. P.
, and
de Witt
,
D. P.
, 1990,
Introduction to Heat Transfer
,
Wiley
, Singapore, pp.
428
467
.
13.
Svendsen
,
S.
, and
Jensen
,
F. F.
, 1994, “
Soltransmittans
,” Lecture note. Thermal Insulation Laboratory, Technical University of Denmark.
14.
Lund
,
H.
, 1995, “
The Design Reference Year Yser Manual
,” Report of IEA-SHC Task 9, Report 274, Thermal Insulation Laboratory,
Technical University of Denmark
.
15.
Kragh
,
J.
et al.
, 2002, “
Grønlandske vejrdata. Nuuk. Uummannaq
,” Department of Civil Engineering, Technical University of Denmark, November.
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