Comparison and analysis of carbon emissions of traditional, prefabricated, and green material buildings in materialization stage

A Carbon Emission Emergy Factor (Em-CEF) accounting model was constructed by combining the carbon emission factor and emergy analysis methods. The Em-CEF model was used to calculate and compare the carbon emissions in the materialization stages of green material, prefabricated, and traditional buildings. The Em-CEF model can calculate the carbon emissions from building materials, machinery, and labor of traditional buildings, as well as from the new green building materials to solve the problem of an incomplete carbon emission factor database. The emergy phase diagram and index evaluation system were constructed to predict the sustainability of different buildings. The overall energy consumption of buildings was evaluated from the perspective of resource consumption. The Em-CEF model establishes an effective analysis method by combining emergy and carbon emission factors in the same system, improving evaluation result reliability. It was found from a case study that the Em-CEF model enabled better selection of carbon emission reduction strategies in the materialization stage; and the carbon emissions of prefabricated buildings were higher than those of traditional buildings. The sustainable development index of prefabricated structures was better than that of traditional and green material buildings and prefabricated structures were more conducive to reducing environmental load and promoting carbon emission reduction.