The majority of tri-generation systems for building applications use the thermal energy rejected by the electrical generator to produce a useful cooling output. An extensive review of the literature has shown that both VAS and desiccant air conditioning systems have been used extensively (Badami and Portoraro 2009). The most common technological pairing has been found to be an ICE with a VAS (Minciuc et al. 2003; Al-Sulaiman et al. 2011; Wu et al. 2014). No research publications have been found describing a SOFC or even fuel cell based liquid desiccant tri-generation system. Due to the lack of work regarding the proposed system, this section of the literature review has been split into four key sections:
- (1) Domestic scale fuel cell tri-generation systems in Sect. 2.5.1
- (2) Large scale fuel cell tri-generation systems in Sect. 2.5.2
- (3) Domestic scale combustion based tri-generation systems in Sect. 2.5.3
- (4) Liquid desiccant based tri-generation systems in Sect. 2.5.4
This approach has been adopted to achieve a broader context of research, with the aim of drawing conclusions that are relevant to the specific SOFC liquid desiccant tri-generation system. Discussions will cover; what has been done to date, transferable lessons from equivalent systems or applications, system design and performance, operating issues and evaluation techniques. The advantages fuel cell technology can provide over conventional combustion based technology in tri-generation system applications is highlighted and the future of fuel cell tri-generation systems in the built environment discussed.
As previously stated, the proposed novel tri-generation system is applicable to a range of building scales. However, the thesis is focussing on the development of a system of 1.5 kWe, and therefore suitable for domestic building use. As a result, the literature review will, where possible, focus on this building type. The attributes that make fuel cells an attractive option for tri-generation system applications have been discussed in Sects. 2.2 and 2.4. Fuel cell CHP systems, of all scales, operating in building applications are well documented in the literature (Hawkes et al. 2009; Ellamla et al. 2015). A fuel cell tri-generation system is in principle very similar to a fuel cell CHP system, the thermal output is simply used in a heat driven cooling cycle instead of serving building heating demands.