Energy and Exergy Analysis of Centralized Solar and Biogas Combined Heating System

The objective of this paper is to propose a centralized solar and biogas combined heating system (SBCHS) applied in rural areas, and to carry out thermodynamic analysis. The thermodynamic model of the SBCHS is established by MATLAB/Simulink, and the energy and exergy flow process of the system are analyzed. The simulation results indicate that the energy efficiency of the SBCHS is 65.4%. The solar fraction is 49.8 %, and the biogas subsystem accounted for 41.3 %. The analysis of the energy and exergy flows shows that a large fraction of the energy losses, mainly in the form of heat loss, occur at the solar collector and biogas boiler. Energy cascade utilization is the key to improve system energy efficiency. Compared with the single heating system, the SBCHS has better thermodynamic performance and economic benefits. The SBCHS provides a promising way for the effective utilization of centralized renewable energy.