A thermodynamic method to calculate energy & exergy consumption and CO₂ emission of building materials based on economic indicator

Due to the data deficiency in developing countries like China, the calculation of the building production phase only considers a few major materials. To solve this problem, three indexes are put forward, which are cost-based energy, cost-based exergy and cost-based carbon, and a new concept, the equivalent coefficient of thermodynamic cost, is presented based on social economic indicator, energy intensity. Then a thermodynamic method is built up to estimate the energy, exergy consumption and CO₂ emission of building materials in production phase. Compared to the conventional calculation, this thermodynamic method takes full account of every material in the BOQ (bill of quantity), and the data used in the method, energy intensity, can be found in government publications. The production phase of the case building is analyzed using this method, and results show that the production phase accounts for 12.34% of the life cycle energy consumption, also contributes 15.48% towards the life cycle CO₂ emissions. The embodied energy of the case building is about 4.995 GJ/m² which matches the results from other LCA research, thus verifies the validity of the proposed calculation. This method is practical and significant in improving sustainable building assessment tools and enacting energy policies in building sector.