Research Of Optimization Method And Integrated Design On Energy Utilizing And Recovery System In Public Building

Energy saving in Public building is one of the key works of energy-saving strategy in china because the public buildings consume large amount of energy and emit large amount of pollutants. In this paper, the energy integration concept was applied to building energy system optimization. Multiple optimization criteria integrated models were established for energy system in different types of public buildings.General physical model of building energy system was constructed. The building energy system was decomposed into energy utilized subsystem (heating, cooling and domestic hot water) and energy utilization and recovery subsystem (steam, high temperature hot water, condensing heat and recoverable waste heat).The models of exergy analysis, exergoenvironmental analysis and exergoeconomic analysis were established based on the second law of thermodynamics, the technical economy analysis and the carbon exergy tax. Optimal design scheme is different under three different optimal objectives. The ground source heat pump features higher exergy efficient while panel floor features superiority on economy and environmental objectives. Consequently, the newly developed methods of exergoenvironmental analysis and exergoeconomic analysis were applied and integrated. The comprehensive optimal scheme was obtained through the integrated optimization objective.Aimed at different-temperature heat energy demanded in public buildings (eg. hospital) developed further optimization to energy utilization and recovery subsystem, considering the different form of energy recovery system between different type of public building. All supplied heat was classified into multiple groups according to their temperature grades, heat requirements and waste energy with different temperature were regarded as cold or heat mass streams to establish an energy utilization and recovery network. Based on pinch analysis and mathematic programming method, a mixed integer nonlinear programming (MINLP) model was formulated for the system considering the seasonal different of energy supply. The GAMS software was applied to solve the model.An energy system of hospital was adopted by applying multiple-criteria optimization (efficient, cost, environmental protect) methodology. Based on the principle of cascade utilization recovery of waste and take seasonal feature of energy system into consideration. Compared with the results of the system without energy recovery, general exergy efficient of raised 6% and a relatively 8.9% of total cost could be saved. The results indicated that the integrated optimal method was practical and effective for building energy system in hospital and hotel.