Energy, Vol.146, 26-33, 2018
Solar thermal networks operating with evacuated-tube collectors
This paper addresses the design and specification of solar collector networks for the capture of solar radiation and its transformation into thermal energy for use in low energy intensity processes. All glass evacuated tube solar collectors are the type of technology considered in this work. Target temperature and heat load are the design objectives in the design of solar collector networks and they are achieved by specification of two design variables, namely: a) number of collectors in series in a row and, b) number of rows in parallel. The variability of ambient conditions is accounted for by means of the specification of the critical point conditions for the design of the network. From the thermal point of view, the number of solar collectors or heat transfer surface area required to achieve the targets depends on the ambient conditions chosen for the design. The targeting approach for the specification of the network structure is based on the use of a thermal model. The various design options available to the designer to specify the number of solar collectors in a row, are presented in a graphical way as a function of mass flow rate, inlet temperature, solar radiation intensity and target temperature. (C) 2017 Elsevier Ltd. All rights reserved.