Analysis of trigeneration plants: engine with liquid desiccant cooling and micro gas turbine with absorption chiller

Abstract

The performances of two natural gas small-scale trigeneration plants are dealt with in the paper. The two plants are part of a new cogeneration and trigeneration system laboratory at the Politecnico di Torino (Turin, Italy), which will be set up and exploited for scientific and technical purposes. The first plant has 126/220/210 kW electrical, heating and cooling capacities, respectively, and it is characterized by an innovative internal combustion engine (ICE) that has been coupled to a liquid LiCl–water desiccant cooling system. The other plant has 100/145/98 kW electrical, heating and cooling capacities and is composed of a micro gas turbine, coupled to a LiBr–Water absorption chiller. The aim of the paper was comparing the performances of the two plants from an energetic and economic point of view; the Primary Energy Savings are calculated for both installations through a commonly accepted methodology proposed by the European Union, and through another methodology, reported in literature, which seems more suitable to describe the energetic performances of trigeneration plants. The savings calculated with this second procedure result to be lower than those of the European Union methodology; moreover, the ICE installation always denotes higher performances with respect to the microturbine. From the economic point of view, it is evident that a fuel tax reduction for high-efficiency cogeneration plants is an essential contribution for the support and development of these systems. Copyright © 2011 John Wiley & Sons, Ltd.