Energy Recovery and Recycle Network Optimization Considering Energy Load Variation for Large Public Buildings

Heat exchange network synthesis has been an effective method in industrial energy recovery system but seldom used in building energy system because of their low enthalpy features. This paper presents a methodology of multi-period synthesis and design optimization of large public building energy system based on pinch analysis concepts and mathematical programming methodology. An updated energy recovery and recycle network (ERRN) with multiple operating periods is constructed while the energy demand and variation trends are considered in deed. Based on heat transfer equation and law of conservation of energy, a mixed integer nonlinear programming (MINLP) model is formulated for the system. Moreover, the model is applied to study a detailed case and it is showed to be robust enough to optimize ERRN for large building. Compared with the result of method designed by maximum load, 8.4% of energy cost and 10.9% total cost savings were achieved.