Biofuel-driven trigeneration systems for non-residential building applications: A holistic assessment from the energy, environmental and economic perspectives.

In the metropolises, it is unlikely to use merely solar and wind energy to pursue zero carbon building design. However, it would become possible if biofuel-driven trigeneration systems (BDTS) are adopted. It is thus essential to assess the application opportunity of BDTS in a holistic way. In this study, BDTS offered definite primary energy saving of up to 15% and carbon emissions reduction of at least 86% in different types of non-residential buildings as compared to the conventional systems. With 24/7 operation for the hotel and hospital buildings, the corresponding BDTS could even achieve zero carbon emissions. All the BDTS primed with compression-ignition internal combustion engine were not economically viable even in running cost due to the high local biodiesel price level. The BDTS primed with spark-ignition engine and fueled by biogas, however, would have economic merit when carbon price was considered for the conventional systems that fully utilize fossil fuels. Adoption of carbon tax and social cost could have the payback ceilings of 8 years and 2 years respectively for most of building types. Consequently, the results could reflect the application potential of BDTS for non-residential buildings, leading the pathway to carbon neutrality for sustainable sub-tropical cities.