(2015) Olcoz Basarte, Íñigo; Astrain Ulibarrena, David; Sanchis Gúrpide, Pablo; García-Barberena Labiano, Javier; García de Jalón, Alberto; Escuela Técnica Superior de Ingenieros Industriales y de Telecomunicación; Telekomunikazio eta Industria Ingeniarien Goi Mailako Eskola Teknikoa
Concentrating solar power is an important way of providing renewable energy. Model simulation
approaches play a fundamental role in the development of this technology and, for this, an accurately
validation of the models is crucial. This work presents the validation of the heat loss model of the
absorber tube of a parabolic trough plant by comparing the model heat loss estimates with real
measurements in a specialized testing laboratory. The study focuses on the implementation in the model
of a physical-meaningful and widely valid formulation of the absorber total emissivity depending on the
surface’s temperature. For this purpose, the spectral emissivity of several absorber’s samples are
measured and, with these data, the absorber total emissivity curve is obtained according to Planck
function. This physical-meaningful formulation is used as input parameter in the heat loss model and a
successful validation of the model is performed. Since measuring the spectral emissivity of the absorber
surface may be complex and it is sample-destructive, a new methodology for the absorber’s emissivity
characterization is proposed. This methodology provides an estimation of the absorber total emissivity,
retaining its physical meaning and widely valid formulation according to Planck function with no need for
direct spectral measurements. This proposed method is also successfully validated and the results are
shown in the present paper.
