Chapter 9 - Residential cogeneration and trigeneration with fuel cells

The energy consumption in the residential sector, due to the electricity appliances consumption, space heating, space cooling and hot water usage, represents, in terms of total primary energy, around 40% in industrialized societies with similar contribution to carbon dioxide emissions. In order to achieve the greenhouse gas emission reduction goal, reinforced by the climate agreement reached at the COP21 climate conference in Paris at the end of 2015, it is essential to develop strategies to make electricity, heating and cooling in buildings more efficient and sustainable. In response to this issue, combined heat/cooling and power (cogeneration/trigeneration) systems, mainly consisting of a prime mover and a heat recovery module fully integrated, are a solution since they generate simultaneously both useful heat and electricity in a single process and from a single energy source. In the last years, Fuel Cell-based systems have gained great attention for application in the residential sector (0.5-5 kW) and are designed to produce heat and power mainly for single and multi-family residential dwellings. With respect to conventional power generation technologies, fuel cells systems offer significant operational advantages, such as higher achievable efficiencies over a broad range of load profiles, reduced noise and vibrations during operation, flexibility of fuel use and, thanks to their high efficiencies, lower emissions without the need for additional controls. Among the different types of fuel cells, Solid Oxide Fuel Cell (SOFC) and Proton Exchange Membrane Fuel Cell (PEMFC) are the most suitable technologies for early market introduction, attracting the most attention and investment in residential application. Thus, in this chapter, SOFC and PEMFC (both low and high temperature) micro-cogeneration/trigeneration systems are presented and examined by considering plant configurations, components, working conditions as well as operational strategies. Moreover, in the case of trigeneration applications different schemes for the absorption chilling unit are evaluated considering their integration with the fuel cell power unit. In order to establish the current status of the technology and its deployment, the main world FC micro-CHP demonstration programs are described and discussed.