Design and Evaluation Strategies for a Novel Hybrid Trigeneration System

Abstract

Renewable energy sources that involve the use of Concentrated Solar Power systems (CSP) are receiving increased attention due to many of the prominent features that it can provide. Most importantly, the simultaneous production of thermal and electrical energy that can be achieved via CSP systems is of great value and constitute many cogeneration processes. Moreover, CSPs have been proven to be an effective source of energy for industrial applications that require high amounts of clean energy, such as desalination. Hence, combining water production activities together with thermal and electrical energy production options via CSP technologies results in novel hybrid tri-generation systems. The possibility of locating such tri-generation systems on the eastern shore of the Mediterranean Sea is investigated in this paper. As such, several different design aspects such as the effect of direct normal irradiance (DNI) on the production freshwater via desalination has been studied. The daily and seasonal intermittency of sunlight, which consists a major challenge for CSP, necessitates the implementation of hybrid systems to ensure a continuous supply of energy for desalination purposes. This paper studies the design of a hybrid trigeneration system under different weather conditions, including four different seasons. The trigeneration system consists of a CSP plant as the main energy source. The system is usually coupled with a conventional fuel source, mainly natural gas, which serves as a backup energy source in the absence of solar energy. A desalination plant comprising of both thermal and membrane technology options for freshwater generation is also included. The design problem is translated into a Mixed Integer Non-Linear Program (MINLP) that can be solved for the optimal network structure based on appropriately selected technologies for steam, power and freshwater production. The environmental aspect of the system has also been studied by quantifying the total amount of carbon dioxide emissions. As such, the integration of a carbon capture technology to regulate those emissions has been also studied, subject to an appropriate value for the overall net carbon reduction target of the tri-generation system.