Influence of climatic conditions on the energy performance of a residential building-integrated micro-cogeneration system

This work examines the performance of a residential building-integrated cogeneration system during the winter season by means of a whole building simulation software, considering the transient nature of building and occupant driven loads as well as the part-load characteristics of the cogeneration unit. A detailed dynamic model (calibrated and validated based on experimental results) was used to simulate a natural gas-fuelled internal combustion engine cogeneration unit with 6.0 kW as rated nominal electric output and 11.7 kW as rated nominal thermal output. Auxiliary thermal energy was supplied by a natural gas-fired boiler and the heat provided by both the MCHP device and the boiler was accumulated within a combined storage tank. The cogeneration system was coupled with a multi-family house composed of three floors, compliant with the transmittance values of both walls and windows suggested by the Italian Law. In order to evaluate the energy performance of the investigated system in various climatic conditions, the analyses were performed by considering the multi-family house located into four different Italian cities (Palermo, Napoli, Roma and Milano) that are to be considered representative of different climatic regions of Italy. The energy impact of the climatic conditions were analyzed by running the micro-cogeneration device under both electric and thermal load-following control strategies. The simualtion data were also compared with the performance of a conventional system composed of a natural gas-fired boiler (for thermal energy production) and the national electric grid (for electric energy production) in order to assess the potential energy saving of the proposed scheme.