Analysis of the Role of Thermal Energy Storage in a Solar-Driven Polygeneration System for a Dairy Industry
Abstract
Solar-driven technologies have a great potential to meet the increasing energy demands in agri-food industrial sectors. Polygeneration systems can produce two or more outputs like electricity, cooling and heating. So, for agri-food industries, combining a polygeneration system with solar thermal energy can be a good approach for producing clean and efficient energy outputs, including heating, cooling and power. The technical, economic and environmental assessment of a proposed Solar Driven Polygeneration (SDP) system consisting of parabolic trough solar collectors coupled with a cogeneration Organic Rankine Cycle, auxiliary boiler, mechanical chiller, and thermal energy storage, covering the heating, cooling and electricity demands of a dairy industry located in Tauste, Zaragoza, Spain, has been studied. Several analyses encompassing: i) the assumption of selling or not electricity to the grid, ii) the study of the role of different thermal energy storages, iii) as well as sensitivity and robustness analyses, have been carried out for the proposed SDP system in order to assess the system performance at different operating conditions. The results showed that the proposed SDP system reached a solar fraction of 76% with a lower cost (close to 30%) and lower greenhouse gas emissions (close to 70%) as compared to the conventional energy supply system. Moreover, it was determined the effective contributions of the different thermal energy storages as well as the positive interaction with the electrical network, which was a “virtual” energy storage, in enhancing the SDP system's performance.
Keywords
Solar-driven Polygeneration System, Solar Thermal Energy, Optimization, Thermal Energy Storage, Agri-food Industries