With the intention to place the University City of Rome in a vanguard position in the use of renewable and low-emission energy sources, it has been planned to subdivide the district in “islands”, each characterized from different energy sources. One phase of this new energetic organization involves the installation of a trigeneration system based on a microturbine for the electric power production and an absorption chiller, fed directly from the exhaust, to supply thermal energy for the satisfaction of the winter energy requirements and of the necessities of summer air conditioning. In the paper, a methodology for the preliminary choice of the main equipment, based on the data provided in the technical descriptions of the suppliers, in order to obtain an objective “evaluation parameter”, is described. The methodology could be useful to synthetize the valence of the project, not only from the economic point of view but also considering the environmental value.