|Authors: (C.J. Renedo, A. Ortiz, I. Fernandez, S. Perez, Department of Electrical and Energy Engineering, University of Cantabria, Santander Cantabria, Spain, and others)
Trigeneration systems are based on the integration of a cogeneration system and an
absorption chiller, which, by producing cold, provides extra heat. This way, a combined
triple power generation is obtained: heat, electricity and cold.
The integration of cold production based on the heat provided by the cogeneration
increases the heat demand in summer. Taking into account that the priority here is to
meet the thermal demand of the system, trigeneration expands the equivalent full load
hours per year of cogeneration, thus increasing the annual production of electricity at the
same time as it becomes more stable.
This chapter starts with an introduction to trigeneration systems, and then moves on
to a review of the fundamentals of absorption refrigeration, with comments on the most
relevant aspects of the thermodynamic process.
This is followed by the presentation of the working fluids and their properties,
which, in absorption refrigeration, are pairs of refrigerant-absorbent fluids.
The single-effect cycle of cold production by absorption is then introduced, and is
followed by a discussion of other more complex cycles. These cycles seek to do two
things: either increase efficiency, or take advantage of thermal sources at relatively low
Finally, one of the most typical trigeneration forms, the District Heating and Cooling
facilities, are considered.