Modelling and Optimization of Transient Processes in Line Focusing Power Plants with Single-Phase HTF

摘要

A large number of commercial and research line focusing solar power \udplants are in operation and under development. Such plants include \udparabolic trough collectors (PTC) or linear Fresnel using thermal oil or \udmolten salt as the heat transfer medium (HTM). However, the continuously \udvarying and dynamic solar condition represent a big challenge for the \udplant control in order to optimize its power production and to keep the \udoperation safe. A better understanding of the behaviour of such power \udplants under transient conditions will help reduce defocusing instances, \udimprove field control, and hence, increase the energy yield and \udconfidence in this new technology. Computational methods are very \udpowerful and cost-effective tools to gain such understanding. However, \udmost simulation models described in literature assume equal mass flow \uddistributions among the parallel loops in the field or totally decouple \udthe flow and thermal conditions. In this paper, a new numerical model to \udsimulate a whole solar field with single-phase HTM is described.\ud\udThe proposed model consists of a hydraulic part and a thermal part that are \udcoupled to account for the effect of the thermal condition of the field \udon the flow distribution among the parallel loops. The model is \udspecifically designed for large line-focusing solar fields offering a \udhigh degree of flexibility in terms of layout, condition of the mirrors, \udand spatially resolved DNI data. Moreover, the model results have been \udcompared to other simulation tools, as well as experimental and plant data,\udand the results show very good agreement. The model can provide more \udprecise data to the control algorithms to improve the plant control. In \udaddition, short-term and accurate spatially discretized DNI forecasts can \udbe used as input to predict the field behaviour in-advance. In this \udpaper, the hydraulic and thermal parts, as well as the coupling procedure, are \uddescribed and some validation results and results of simulating an \udexample field are shown.