Energy Consumption Model Calibration And Energy Efficiency Evaluation For Central Cooling Plant

Graded energy efficiency evaluation of central cooling plant system,subsystems and equipment can find weak links of energy efficiency and improve energy efficiency of central cooling plant.However,detailed evaluation requires energy consumption data of each equipment.In practice,most energy consumption monitoring platforms can only provide partial operation data,such as the total energy consumption,some points’ temperature,flow and pressure,which cannot support the hierarchical energy efficiency evaluation.In this paper,a method of energy consumption model calibration and energy efficiency evaluation for central cooling plant is proposed.Its realization process is divided into four steps.Firstly,the operation data of central cooling plant need to be collected and preprocessed.Secondly,aiming for the minimum error between the simulated and the measured total energy consumption,the energy consumption model of central cooling plant is calibrated.Then,the hourly simulation energy consumption of each device is obtained using the calibrated model.Finally,the graded energy efficiency of central cooling plant is evaluated with the temperature,flow provided by the central cooling plant and the simulated energy consumption.The proposed method is verified with a central cooling plant in Shanghai.The hourly average CVRMSE of simulated and measured total energy consumption of central cooling plant is 3.48%.The hourly average CVRMSE and MBE of simulated and measured energy consumption of 14 equipment are within 8.5% and ± 6.5% respectively.The relative errors of energy efficiency indexes calculated respectively by the simulated and measured energy consumption are within ± 7.5%.Further analysis shows that the hydraulic balance of three chillers and three secondary pumps are good.The No.2 chiller has better performance,the average COP of No.3 chiller is the highest,and that of No.1 chiller is the lowest,there may be faults.The efficiency of the secondary pumps are between 0.4 and 0.5,and the average efficiency of the No.1 secondary pump is 0.44,there may be faults.The energy efficiency of No.2 primary pump is lower.No.3 cooling pump and cooling tower have higher energy efficiency.The above analysis results provide effective technical support for the energy-saving operation and improvement of the central cooling plant.Finally,based on the GUIDE graphical user interface of MATLAB,a software for energy consumption model calibration and energy efficiency evaluation of central cooling plant is developed,which can complete the calibration and energy efficiency evaluation process on the graphical operation interface,and expand the practicability of the proposed method.