Study On Control Strategy And Energy Saving Of Central Air Conditioning Operation In Public Buildings

In recent decades,the total energy consumption of buildings has increased with the rapid development of the construction industry.The HVAC system of public buildings accounts for a relatively high energy consumption of buildings,so it is necessary to optimize the energy-saving of HVAC systems in public buildings.The HVAC operation control and energy saving strategy of hospital buildings is mainly studied.The main goal is to develop and optimize the automatic control system of the HVAC system by establishing the building energy consumption model,combined with the load forecasting method and fuzzy PID algorithm with Smith predictive control.Fistly,the basic information of the target building was analyzed,and the building energy consumption model was established by using the energy consumption simulation software.To prove reliability of simulation data,the model was verified by measured data.The model analyzed the annual energy consumption variation characteristics of different equipment in the HVAC system.The results showed that the GSHPs consumed the most amount of energy,accounting for 64.6% of the total energy consumption of the HVAC system,while energy consumption of pumps accounted for 19.9% of the total energy consumption.Through the comparison of impact factors,the sensitivity of building energy consumption to different variables was studied.The results showed that the total energy consumption of HVAC system was most affected by the indoor design temperature,and the impact factor can reach above 0.5.Considering the ambient temperature and humidity and the total load of the HVAC system in the previous cycle,the energy consumption prediction formula was fitted.The results showed that the prediction method could accurately predict the total building load and kept the correlation coefficient of the prediction at 0.99.Secondly,based on the control of the variable flow,the mathematical model of water system was established.The response speed of the system was studied by the fuzzy PID control method with Smith predict control and compared with other control methods.The results showed that the fuzzy PID control technology with Smith predictive control not only had faster system response speed,but also greatly reduced the phenomenon of overshoot and oscillation.Besides,the anti-interference and robustness were also stronger.Fianlly,based on the automatic control system of the HVAC system of a hospital building,the main frame structure of the system was discussed.The automatic control system was established by PLC and host computer.The implementation method of fuzzy PID control technology in PLC and the idea of applying predictive control method to PLC were discussed.The operating characteristics and energy consumption of the components were compared through the data collected by the automatic control system.The results showed that through the optimized automatic control system,the equipment operation status could be optimized,and the overall energy consumption level of the HVAC system could be effectively reduced by 66,000 kWh per year,and the energy saving rate could reach 8.8%.The cost of pumps could be reduced by the optimized variable flow control system with energy saving of 43,200 kWh during summer,which account 65% of the total energy saving.The above research questions have solved many problems in the research of building energy-saving design,and provided ideas for future research.