Similar Condition Calculation Method For Energy Saving Retrofit Of Air Conditioning System Based On Energy Consumption Monitoring

Energy saving retrofit of central air conditioning system is one of the key points of energysaving retrofit of existing large-scale public buildings in China.The built building energy consumption monitoring platform provides big data resources for quantitative evaluation of air conditioning system energy saving retrofit.At the same time,EMC provides a feasible project implementation mode for energy saving retrofit of air-conditioning system.There are many factors affecting the energy consumption of before and after the energy-saving retrofit of central air conditioning system.Due to the large number of factors,complex process and difficult calculation of energy saving,energy consumption monitoring data and contract energy management mode have not been recognized by all parties in energy saving retrofit in practical application.This greatly limits the development of energy-saving retrofit technology of existing buildings and their air-conditioning systems in China.Therefore,it is urgent to deeply study the scientific and reasonable calculation method of energy saving before and after energysaving retrofit of air conditioning system.Relying on the massive data resources of building energy consumption monitoring platform,this paper systematically discussed the research progress of relevant issues at home and abroad,and then studied the suitable energy-saving calculation method for the energy-saving retrofit of existing building air-conditioning system in China.The specific contents are as follows.Firstly,in order to accurately calculate the energy saving of energy-saving retrofit by using energy consumption monitoring data,this paper analyzes the types and key parameters of energy consumption of air-conditioning system based on i BES,internent of Building Energy System.The dynamic mathematical model of building indoor cooling load and the key parameters affecting its size are analyzed.The key parameters of monitoring and accurately characterizing the energy consumption of air conditioning system were summarized by using i BES,and the characteristic parameter set of energy consumption comparison of air conditioning system energy saving retrofit was proposed.Second,the same or similar indoor and outdoor operating parameters are the premise for comparative analysis of the operating energy consumption of air conditioners before and after energy-saving retrofit.Based on the characteristic parameter set of energy consumption comparison of air-conditioning system energy saving retrofit,the definition and direct judgment method of air conditioning energy consumption comparison analysis of similar conditions before and after energy saving retrofit are proposed.The real-time acquisition method of various parameters under similar conditions suitable for i BES is studied,and the influence of operating conditions parameters on air conditioning energy consumption is studied by orthogonal experimental analysis method,which further simplifies the characteristic parameter set of energy saving calculation.Thirdly,accurate judgment of similar working conditions is the key to accurately calculate energy saving before and after energy saving retrofit.Based on the hourly variation characteristics of each working condition parameter and its influence on air conditioning energy consumption,a comparative analysis method of energy consumption of air conditioning system energy saving retrofit combination with similar daily weight is proposed,and the calculation method of classified weight coefficient and hourly weight coefficient of each working condition parameter is given.On this basis,the method of calculating the energy saving of the air conditioning system before and after energy saving retrofit is put forward.Fourthly,eliminating abnormal data in energy consumption monitoring data is the premise to accurately find and judge the similar working conditions and calculate energy saving.In this paper,we introduce POD,LSE and FCD methods,and propose an online recognition method for abnormal feature of the correlation dimension of energy consumption data.The consistency of the variation characteristics of POD temporal time coefficient and POD-LSE temporal coefficient and the feasibility of this method to identify abnormal data by partial branches are verified by using multi-branch lighting socket electricity sample data.The identification effect of this method on abnormal data under different calculation step sizes is analyzed,and the appropriate calculation step size is determined,which provides data quality guarantee for effectively eliminating abnormal data,accurately judging similar working conditions and saving energy in scientific calculation.Finally,in order to verify the accuracy and scientific nature of the above research methods,the combined weight similar daily energy saving calculation method is applied to the energy saving calculation project of a building in Wujiang,Suzhou.The effective data of working condition parameters and energy consumption parameters of the project before and after energy-saving retrofit are obtained by using the above methods of obtaining indoor and outdoor working condition parameters and abnormal data identification.Using the effective data,the weight coefficients and the similarity error limits of working conditions were determined,and the similarity days of working conditions before and after the energy saving retrofit were obtained.The energy saving of three cooling periods,two heating periods and two transition periods after energy saving retrofit is calculated.The results show that the energy consumption comparison characteristic parameter set including outdoor temperature and humidity,solar radiation intensity,power consumption of lighting socket,total power consumption of air conditioning,etc.can meet the energy saving calculation requirements of the project before and after the energy saving retrofit.The online recognition method of POD-LSE-FCD method can quickly and effectively identify abnormal data in energy consumption monitoring,and improve the accuracy of similar conditions judgment and energy saving calculation.The combination weighting methods similar conditions can be more easily to get,for this project,similar days in the validation period account for 20% to 42% which accounts 25% ～ 48% consumption.After the energy saving retrofit of the project,the verified periodic energy saving(energy saving rate)in three cooling periods is 119957 k Wh(9.48%),187182 k Wh(14.80%)and 267802 k Wh(21.17%),the verified periodic energy in two heating periods is 90930 k Wh(11.47%)and 136930 k Wh(17.28%),and the verified periodic energy in two transition periods is 40040 k Wh(9.43%)and81321k Wh(19.15%).This paper provides a basic theoretical method for the accurate calculation of energy saving before and after the existing building energy saving retrofit,and facilitates the quantitative evaluation of the existing building energy saving retrofit effect.It has important theoretical significance,and has important practical significance for the development and application of energy saving retrofit model of contract energy management in China.