SOFC Tri-generation System Modelling and Analysis
In recent years, the dramatic increase in fossil fuel prices and the accompanying concerns regarding their environmental impact have driven governments, business and consumers towards cleaner energy resources and to use alternative methods for more efficient energy utilisation. Compared to a conventional separate generation scenario, energy conversion in a tri-generation configuration offers the potential for high energy efficiency and thus greater energy utilisation, providing a range of technical, environmental and economic benefits (Jradi and Riffat 2014d).
Chapter 3 has presented validated liquid desiccant dehumidifier and regenerator models. This chapter presents a theoretical analysis of the complete tri-generation system, integrating SOFC and liquid desiccant technology. The SOFC CHP system will produce an electrical and thermal output. The liquid desiccant dehumidifier will generate a cooling output. To facilitate continuous operation of the liquid desiccant air conditioning system the SOFC thermal output will be used for desiccant solution regeneration. As previously highlighted in Chap. 2, no work has been found in the literature regarding an SOFC liquid desiccant tri-generation system, thus the work in this chapter provides a contribution to knowledge through a theoretical analysis of the novel system. The aim of the chapter is to demonstrate the feasibility of combining SOFC and liquid desiccant air conditioning technology into an efficient and effective tri-generation system. The work presented seeks to quantify and qualify the benefits of combining the two technologies, to provide a comparison of performance compared to a conventional separated system and to offer a benchmark of perfor- mance/operational considerations for the experimental tri-generation system.
A schematic of the modelled tri-generation system is provided in Fig. 4.1, and is comprised of two main sub components, the SOFC CHP system and the desiccant air conditioning system. The complete tri-generation system is truly multifunctional, generating an electrical, heating and cooling output.
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T. Elmer, A Novel SOFC Tri-generation System for Building Applications, Springer Theses, DOI 10.1007/978-3-319-46966-9_4
Fig. 4.1 The modelled tri-generation system
This chapter is split into two sections. Section 4.2 provides a theoretical performance analysis of the tri-generation system’s SOFC and liquid desiccant subcomponents. The sub-component assessment focuses on the impact changes in operating values have on their performance. The analysis serves two purposes (1) to improve the understanding of the sub-component operation and its influence on performance, and (2) selection of specific sub-component operating values to facilitate effective tri-generation system integration.
Section 4.3 integrates the SOFC CHP and liquid desiccant sub-components into a complete tri-generation system. Firstly, a specific tri-generation system case, based on defined selection criteria, is presented. Following this, a parametric analysis is used to investigate the effect changes in electrical and cooling capacities have on tri-generation system performance. A 24 h tri-generation system simulation is also provided. Finally, a climatic performance investigation is presented for three locations. Throughout, the performance of the novel SOFC tri-generation system is compared to a conventional separated system comprising grid electricity, gas fired boiler and vapour compression cooling. Finally, conclusions based on the theoretical assessment that are relevant to the experimental system are provided.