Local emissions of a residential building-integrated micro-cogeneration system

The increasing diffusion of micro-cogeneration systems is raising the need for studying their environmental impact in order to assess their sustainability. The adoption of the systems for the combined production of heat and power may provide, as a consequence of cogeneration enhanced overall energy efficiency, a significant reduction of global impact in terms of CO2 emissions with respect to the separate production of electricity and heat. However, a comprehensive evaluation of this technology should take into account as well the impact due to the presence of plants spread over the territory that could increase the local pollution, in particular due to NOx and CO, and thus could worsen the local air quality.In this paper the NOx and CO emissions of a residential building-integrated micro-cogeneration system were evaluated and compared with those of a conventional system composed of a natural gas-fired boiler (for thermal energy production) and the central electric grid (for electricity production). The analyses were carried out by using the whole building simulation software TRNSYS. A natural gas fuelled internal combustion engine-based MCHP unit coupled with a multi-family house compliant with the transmittance values suggested by the Italian Law were considered.