Abstract. This paper presents the model developed to compare a trigeneration system to existing heating, cooling and electricity generation methods. The archetype of a typical 13 storey multi-unit residential building has been simulated in TRNSYS with an array of commercially available cogeneration units. These units provide the required heating to the building through water storage and produce electricity as a subsidiary. During cooling periods heat from these units fuels a combination of absorption machines modelled especially for this application. Results show a reduction of primary energy consumption compared to an actual scenario. Further analysis of the controls and storage size would be required to optimize this system.