Investigation of the ratio of exergy consumption to energy consumption for building energy efficiency

The Ratio of Exergy consumption to Energy consumption (REXE) of the building is defined in the paper. The building life cycle REXELC provides a full understanding of high-quality energy consumption during the building life cycle. It is proposed as a new thermodynamic parameter to evaluate the building life cycle energy efficiency. It also can be applied as a simplified way to calculate the building life cycle exergy consumption. Five public buildings in China are taken as the study cases. The energy consumption, exergy consumption, and cost per construction area of the five cases are calculated to study the parameter REXELC. It is concluded that the building life cycle REXELC mainly depends on the energy consumption proportion and REXE of the building material's production stage and building running stage. The economic analysis of the buildings shows that the building with too large or too small REXELC would not be the economic one. At last 2 mathematical regression models are established to investigate the relation between building life cycle energy consumption and REXELC. According to the regression model, all the buildings can be divided into four zones. The REXELC would be an important instruction in optimizing the design of building envelope.