Research On The Energy Consumption Simulation And Optimization Control Of Mall Central Air-conditioning System

Energy consumption, energy saving and environmental protection is the focus of attention in today's society, many cities have emerged energy shortage problem. The central air-conditioning as the large energy consumption, the energy consumption analysis and energy saving control research is of great significance. The energy consumption of the air-conditioning system is closely related with control system, building types, envelope, climate characteristics, personnel flow and equipment cooling and other internal and external disturbance. Which requires the study of energy saving control scheme must be based on the whole building, and the present control study mostly from the actual construction and the whole air-conditioning system, limited to some single link.First of all, this thesis introduces the basic principle of the composition and refrigeration of the central air-conditioning systems, studying on the influence of some factors on the performance and energy consumption of the air conditioning, such as refrigeration units, system efficiency COP, partial load factor IPLV, the matching scheme of refrigeration units' operating number, backwater temperature difference and the size of fluid flow, analyzing the impact of all sectors on the energy consumption of large department stores, and putting forward the energy saving control scheme along with the load change.Next, this paper using the comprehensive heat transfer, thermodynamics, fluid mechanics and other knowledge in Trnsys software re-build accurate mathematical model of central air conditioning systems, including pumps, fans, air/water pipe, valve assembly, to make up the shortage of Trnsys software only considering the thermodynamic characteristics of pipe network while ignoring the hydraulic characteristics.Then, this paper set up the project model of the business building and central air conditioning system in the Trnsys software, simulating air conditioning room temperature and cold and hot load, and the combined control scheme of all air conditioning system is put forward, including variable flow optimizing control of air supply, air return, fresh air and chilled water secondary pump, the matching scheme of refrigeration units, and the optimizing start-stop control of the number of units.By comparison with the original benchmark air conditioning system, the paper comprehensively analyzes the control effect. Through simulating each optimized control link and overall system energy consumption, the link saving ratio was 26.76%, 61.94%, 22.95%, 20.68%, 35.75% and 26.95%, overall energy-saving air-conditioning system was 26.95%. The results show that the energy conservation effect of optimization control system is good from a single control link to the overall system.