Change search
ReferencesLink to record
Permanent link

Direct link
Gas-filled, flat plate solar collectors
Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
2012 (English)Doctoral thesis, monograph (Other academic)
Abstract [en]

This work treats the thermal and mechanical performances of gas-filled, flat plate solar collectors in order to achieve a better performance than that of air filled collectors. The gases examined are argon, krypton and xenon which all have lower thermal conductivity than air. The absorber is formed as a tray connected to the glass. The pressure of the gas inside is near to the ambient and since the gas volume will vary as the temperature changes, there are potential risks for fatigue in the material. One heat transfer model and one mechanical model were built. The mechanical model gave stresses and information on the movements. The factors of safety were calculated from the stresses, and the movements were used as input for the heat transfer model where the thermal performance was calculated. It is shown that gas-filled, flat plate solar collectors can be designed to achieve good thermal performance at a competitive cost. The best yield is achieved with a xenon gas filling together with a normal thick absorber, where normal thick means a 0.25 mm copper absorber. However, a great deal of energy is needed to produce the xenon gas, and if this aspect is taken into account, the krypton filling is better. Good thermal performance can also be achieved using less material; a collector with a 0.1 mm thick copper absorber and the third best gas, which is argon, still gives a better operating performance than a common, commercially produced, air filled collector with a 0.25 mm absorber. When manufacturing gas-filled flat plate solar collectors, one way of decreasing the total material costs significantly, is by changing absorber material from copper to aluminium. Best yield per monetary outlay is given by a thin (0.3 mm) alu-minium absorber with an argon filling. A high factor of safety is achieved with thin absorbers, large absorber areas, rectangular constructions with long tubes and short distances between glass and absorber. The latter will also give a thin layer of gas which gives good thermal performance. The only doubtii ful construction is an argon filled collector with a normal thick (> 0.50 mm) aluminium absorber. In general, an assessment of the stresses for the proposed construction together with appropriate tests are recommended before manufacturing, since it is hard to predict the factor of safety; if one part is reinforced, some other parts can experience more stress and the factor of safety actually drops.

Place, publisher, year, edition, pages
Göteborg: Chalmers University of Technology , 2012.
, Technical report D - Department of Building Technology, Building Services Engineering, Chalmers University of Technology, ISSN 0346-718X ; D2012:02
Keyword [en]
Solar collectors, Modelling, Mechanical stresses, Heated cavity, collector material
Research subject
Energi, skog och byggd miljö, Högeffektiva solfångare för svensk produktion
URN: urn:nbn:se:du-6182OAI: diva2:523432
Available from: 2012-01-04 Created: 2012-01-04 Last updated: 2012-04-24Bibliographically approved

Open Access in DiVA

fulltext(6695 kB)1144 downloads
File information
File name FULLTEXT01.pdfFile size 6695 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Vestlund, Johan
By organisation
Energy and Environmental Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 1144 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 771 hits
ReferencesLink to record
Permanent link

Direct link