Case of energy system in a green building in tianjin

Abstract

Combined cooling, heating, and power (CCHP) system plays a significant role in efficient utilization of energy. In this chapter, a case study on energy system in a green building in Tianjin is presented. As for the energy system, a typical CCHP system is proposed including a power generation unit (PGU), an absorption chiller, and a ground heat source pump (GSHP) to substitute conventional electric chiller and auxiliary boiler. Then a matrix modeling approach is presented to optimize the CCHP system. Modeled in a matrix form, the CCHP system can be viewed as an input-output model. Energy conversion and flow from the system input to the output is modeled by a conversion matrix including the dispatch factors and components efficiencies. By designing the objective function and determining the constraint, the optimization problem of minimizing the comprehensive performance (CP) of operational cost, carbon dioxide emission, and primary energy consumption is solved. Thus the size of the PGU and GSHP is optimized using the linear search method. After that an illustrative case study is conducted to present the effectiveness, and results show that the thermal load and electric load are well satisfied by the proposed system no matter judging from the typical daily aspect or monthly aspect or annual aspect. Finally, the on-site energy matching (OEM) and on-site energy fraction (OEF) are employed to evaluate how much on-site generated energy is exported or wasted and how much demands are covered by the on-site generated energy. The results showed that the produced energy of the CCHP system is not fully used, while it can well satisfy the end user load.