The Study Of Energy Efficiency Diagnosis Methodology For Air-Conditioning Systems With The Actual Operating Data

In recent years, studies of energy efficiency diagnosis of air-conditioning system have been a concern. As a typical energy efficiency diagnosis methodology for air-conditioning system, OTI (Observation/questionâ†'Test/calculationâ†'Identification/resolution) has been widely used in most diagnose analysis of actual projects. But it has obvious disadvantages. For example, this method needs to be tested and evaluated frequently according to the actual system condition and needs diagnose indicators of artificial selection. But in actual diagnose process, it also needs to be changed and adjusted to adapt to different requirements of different program. That is to say, it is used only on specific issues. In recent years, many researchers have been tried to develop and improve both new and old methods. But in terms of current methods, it still belongs to OTI’s category. Therefore, there is no need to discuss whether the diagnose method is revolutionized or not.On the other hand, system operating data has directly and truly reveals the real operating condition of air-conditioning system. In order to achieve saving the energy of air-conditioning, one important method is to monitor the operating data automatically and reduce system operating energy by taking corresponding control strategy. Currently, many air-conditioning systems of buildings have achieved collecting operating data and large amounts of data which are accumulated from the system have provided a foundation for analyzing both energy condition and operating circumstances of the system. But large amounts of data also cause a data disaster which makes managements hardly to find energy waste and abnormal energy problems quickly and efficiently.Therefore, this paper proposed a new energy efficiency diagnosis methodology based on the actual operating data of air-conditioning system. From the aspects of data processing, data analysis and energy efficiency potential calculation, the methodology was researched. The detailed studies are as follows:Firstly, a more typical case which was an ice storage air-conditioning system was chosen in the paper in order to expound the research work better. Then, the operating data of air-conditioning system were comprehended from the perspectives of data attributes and specialty attributes of the operating data of the case. Finally, the operating data of air-conditioning system were defined as the different scales of multi-source heterogeneity tracking data with time lag of two-way interaction.Considering the deficiencies of a typical energy consumption diagnosis method, the energy consumption space-time diagnosis method was put forward, based on the comprehension of the operating data. Meanwhile, the 5W2H analysis method was introduced to evaluate these two methods from the perspectives of factors composition of energy consumption activities. Afterwards, the basic requirements were proposed for the diagnosis data quality. The data preprocessing which was crucial procedure before the formal diagnosis work, and the first stage of the energy consumption space-time diagnosis, was introduced with strong pertinence and practicality.As the second stage of the energy consumption space-time diagnosis of air-conditioning system, the two main method, longitudinal research and cross-sectional research were used from the two levels of time distribution and space distribution of energy consumption of air-conditioning system based on the case data. Equipment frequency conversion characteristic, systems operation strategy, equipment operation sequence, actual offside operation analysis, system condition pattern recognition, equipment actual operation feature of the air-conditioning system were analyzed and studied, which were related to energy efficiency potential analysis.Various heat constraints of air-conditioning system energy consumption model were deduced and analyzed in the third stage of the energy consumption space-time diagnosis. The energy efficiency operation optimization methods applied in the paper were restricted specifically combined with the characteristics of actual operating data after analyzing system energy efficiency operation optimization principle.At last, the particle swarm optimization algorithm (PSO) was introduced to calculate system energy efficiency potential in the case. A particle swarm evolutionary drive mode adapt this problem mechanism was proposed. Considering all the constraints synthetically, the predetermined load distribution scheme was rescheduled in accordance with energy consumption calculations in order to obtain the solutions meeting the practical application.To sum up, the new energy efficiency diagnosis methodology for air-conditioning systems putted forward in this paper, by using the actual operating data of air-conditioning systems, studying the actual operating features of systems and equipment, and calculating the energy benchmarking (or cost benchmarking) of systems, it can provide the important information for energy efficiency potential rapid judgment and system optimization of air-conditioning systems.