Flat plate thermal solar collector efficiency: Transient behavior under working conditions part II: Model application and design contributions Articles uri icon

publication date

  • October 2011

start page

  • 2385

end page

  • 2393


  • 14-15


  • 31

international standard serial number (ISSN)

  • 1359-4311

electronic international standard serial number (EISSN)

  • 1873-5606


  • An experimental research was performed on a solar facility with a nine-year-old, on-campus field with 50 m(2) area of flat plate solar collectors. A transient model was developed, adapted to the characteristics of this facility and experimentally validated as described in Part I of this paper. The efficiency normalization curve (ENC) operating conditions for the steady-state test are different from the working conditions. Significant differences between the ENC and the model based predictions were found and quantified. The significance of the transient behavior is compared with the thermal inertia proposed in the EN-12975:2006 standard for the quasi-dynamic test. Using the model capabilities to predict the collector performance under transient working conditions, the influence of the operating conditions on the collector efficiency and on the useful heat produced is studied individually. The relevance of those conditions is ranked as follows: the wind (velocity magnitude and direction) was the most influential, followed by the aging of the collector surfaces, convective heat losses, thermal inertia and the incident angle of irradiance.


  • solar energy ; flat plate collector ; transient model ; collector thermal efficiency ; collector performance ; solar domestic hot water