Comparison of systems for integrated cogeneration and district energy

Abstract

Systems for integrated cogeneration and district energy are compared, pointing out similarities and differences. The cases considered in the comparison exercise are carefully described, including the specification of efficiency measures. Performance and efficiency measures are defined and discussed for the chillers, for cogeneration and heating, and for integrated cogeneration-based district energy. The comparison of several systems for integrated cogeneration and district energy demonstrates the merits of different integrated systems for cogeneration and district energy, and also clarifies the separate technologies involved and how they operate in tandem in mutually beneficial manners. The comparison highlights the need for proper measures of merit for systems for cogeneration-based district energy, particularly when they include cooling, and the way in which district cooling systems using absorption chillers can complement district heating systems when both use heat supplied from a cogeneration plant because the demand for heat become more balanced seasonally. Comparative assessments are demonstrated to be both useful and necessary, given the breadth of technologies available for cogeneration, heating, cooling, district heating and district cooling, particularly as a way of assisting designers in selecting parameter values and system configurations, and in helping decision-makers choose among competing options. The comparisons in this chapter also serve to illustrate the technologies that are involved in cogeneration-based district energy, and to help demonstrate the merits of different integrated cogeneration and district energy systems by providing fair comparative assessments.