A design tool for a parabolic trough collector industrial process heat system based on dynamic simulation

Abstract

The most effective way to reduce the use of fossil fuels for energy production is by employing renewable energy systems. From the various types of renewable energy sources, the mostly used one is solar energy. Especially for Cyprus, the ratio of direct to diffuse solar radiation is 70:30, and thus a parabolic trough collector system (PTC) would be the perfect system for thermal energy production for high temperatures. It is very important to focus on renewable energy systems for the industrial sector specifically since the industrial sector is the second largest fuel consumer in Cyprus. Thus, PTC systems for low temperature steam production can be used in several industries to reduce fuel consumption. In this work, initially, an investigation of PTC systems used worldwide has been carried out, discussing also how this technology has been improved through the years. Next, an extensive literature review is carried out, which is classified into two sections; in the first one, an investigation has been done of PTC prototypes, thermal energy storage and Transient System Simulation (TRNSYS) simulation models which are mainly used for industrial process heat (IPH) applications, and in the second section, an overview of the Cyprus energy status is presented in order to investigate the potential of using this technology for IPH by the Cyprus industries. Subsequently the novel PTC system installed in an industry in Cyprus is described and analyzed through experimental and numerical investigation. A dynamic simulation model is built in TRNSYS simulation tool to investigate the performance of the system which is then validated using the monitoring data from the real PTC system installed at the factory. The novelty of this study is the development of a design tool based on a scaled-up model built in TRNSYS, which allows the potentially interested industries to identify the suitable system that fits their needs. All data are provided in the form of graphs and allow anyone to use as input data the thermal energy demand and required steam temperature of the industry to retrieve information about the size of a suitable system that satisfies these requirements depending on each case. The payback period for all cases examined varies from 2 to 6 years, depending on the size of the system.