Modelling of a Small-Sized Parabolic-Trough Solar Collector Field for Process Heat in the Cork Industry
Abstract
The potential of solar energy for industrial processes has been demonstrated by International Energy Agency (IEA) Task 33 Solar Heat for Industrial Processes. A large number of industrial process heat (IPH) facilities with parabolic-trough collectors (PTCs) erected since the eighties, mainly in the U.S.A., but also in Europe, some of which are still in operation, confirm that small-sized parabolic-trough collectors are the best solar option in a temperature range from 80 to 250ºC. This paper presents design process and simulation results of a small-sized PTCs field pilot plant for supplying process heat in the cork industry in Badajoz (Spain), in which raw cork must be processed by immersion in hot water at 98ºC for one hour to eliminate any taste before being used in the food industry. There is no previous experience in application of solar heating in processing cork. A model with TRNSYS simulation environment of the PTC solar field was developed to take design decisions, such as PTC type, optimum size and configuration of the solar field and piping layout. This simulation environment was also used to analyze the performance of the selected solar field configuration over the operation period. According to results obtained, the solar field supplies 65% of the industrial process heat demand, with 50% annual system efficiency and 50% savings in the fossil energy required for conventional cork processing. Implementation of the system designed is expected to produce references and guidelines for future installations in the geographic area of the pilot project, characterized by high solar resource availability as demonstrated by the rapid deployment of CSP facilities in recent years.