Abstract: in this paper, the specific classification and itemized energy consumption devices of the equipment installed in the energy consumption monitoring system of large public buildings will be analyzed in detail, and the data information detected by the energy consumption of large public buildings will be dynamically analyzed with the help of GPRS / Wi Fi and other wireless transmission technologies, so as to make a practical contribution to the cause of energy conservation and consumption reduction in China, Monitor the energy consumption of large public buildings, and effectively optimize and control if excessive energy consumption is found.

Key words: monitoring system; Energy consumption device; Control system

0.Background

 China's Ministry of construction has proposed that through the statistical analysis of big data, by the end of 2020, the total construction area of the country has exceeded 40 billion square meters, and the building energy consumption will reach 1.09 billion tons of standard coal. The energy directly consumed by buildings in the process of construction and use has accounted for about 30% of the total energy consumption of the whole society. At present, there are some problems in the measurement, transmission and energy-saving supervision of energy consumption of large public buildings in China. Extensive energy consumption management will cause a lot of energy consumption waste to a certain extent. Energy consumption monitoring and energy-saving management of large public buildings have become the focus of energy conservation and consumption reduction in China. Although China has carried out the supervision of informatization, there are many problems of concealment in the process of data reporting, which directly increases the difficulty of energy consumption data statistics because of the low degree of automation of data collection and low degree of management informatization. In order to achieve accurate energy consumption data collection and effective dynamic control of energy consumption, this paper will analyze the energy consumption monitoring system of large public buildings in detail.

1. Development of energy consumption monitoring system for large public buildings at home and abroad

   Looking abroad, foreign intelligent building technology has been relatively mature, and the intelligent and automatic level of energy consumption data and information monitoring is also relatively high. For developed countries, especially for large public buildings, great attention is paid to energy consumption monitoring, intelligent energy consumption monitoring equipment is constantly improved, and the engineering system operates stably. For China, although intelligent building technology has been applied, it lacks systematic intelligent building integration system, relevant concepts and ideas have not been formed, and there is still a large gap with foreign countries. During the operation of many intelligent building systems in China, the lack of overall operation mechanism of relevant systems will lead to the problem of twice the result with half the effort, resulting in a waste of investment. The real-time, reliability and stability of intelligent building monitoring system are difficult to reach the world standard level. At present, many foreign information technology enterprises have developed matching systematic products for the energy consumption monitoring system of large public buildings. American Honeywell, American Johnson Controls, German Siemens and other companies have actively carried out the research and development of energy consumption monitoring system products, so as to promote the operation of energy consumption monitoring system of national large public buildings to be more stable and efficient. Although there are imperfections in the development of intelligent buildings in China, they are actively developing under the joint efforts of the state and enterprises. China's Shanghai Yuanshang energy consumption measurement and management system and Advantech BEMS building energy management system all show their unique value and are widely used in the energy consumption monitoring of large public buildings in China.

2 Energy consumption monitoring data collection of large public buildings

2.1 Energy consumption monitoring data collection

 The internal data system of energy consumption of large public buildings is complex, and there are many energy consuming units. In order to do a good job in the framework of energy consumption monitoring system of large public buildings, it is necessary to control the content of energy consumption monitoring data of large public buildings. According to the requirements in the specific contents of state organ office buildings and large public buildings issued by China, the monitoring content of energy consumption data information of large public buildings is shown in Figure 1.

Figure 1 energy consumption monitoring data collection content

2.2 Energy consumption monitoring data processing

 In the process of energy consumption monitoring of large public buildings, the energy consumption data information can be detected with the help of general inspection and metering devices, and various data can be monitored on the basis of clarifying the peak and valley values of energy consumption metering devices. Verify the power in the watt hour meter. In order to ensure the effectiveness of data and information collection, data and information collection can be carried out twice in a row, and the errors of the two data and information collection can be controlled to ensure that the power is less than twice the peak power of the energy consuming equipment on the road. On the basis of ensuring the accuracy of data information collection, it is also necessary to carry out sub item energy consumption data calculation, carry out detection with the help of metering devices, and ensure the measurement and detection level in combination with the calculation method of various energy consumption indicators.

3 Construction framework of energy consumption monitoring system for large public buildings

3.1 System framework

The energy consumption monitoring system of large-scale public buildings studied in this paper is designed in close accordance with the requirements of "energy consumption monitoring system of state organ office buildings and large-scale public buildings - software development guidance manual", which effectively meets the design standards specified in our country. The framework construction mode of energy consumption monitoring system for large public buildings is shown in Figure 2. Its main purpose is to obtain the front-end data information of the collector. For the information resources and data layer, it is to achieve the acquisition and transmission of first-hand energy consumption data information in large public buildings, and classify the collected energy consumption data information. For the application layer, it covers four levels: data and information management, analysis and display, information service and background management. Many words are covered in different levels. The function of the application layer in the energy consumption monitoring of large public buildings is used for energy consumption data information processing, display and data information monitoring. In the application layer, each function can be regarded as an independent system module. When designing the application layer module, each processing module should be relatively independent to reduce the mutual interference between each module and pave the way for the subsequent energy consumption data information processing. For the performance layer, it is to analyze the energy consumption data information of large-scale public buildings for different roles in the society in combination with their own actual needs.

Figure 2 construction framework of energy consumption monitoring system for large public buildings

3.2 Software architecture

 The energy consumption monitoring of large public buildings is generally controlled and managed with the help of software app. The energy consumption monitoring system software of large public buildings mentioned in this paper covers monitoring terminal, database, data management system, data acquisition system, firewall, communication network, concentrator and building data information acquisition terminal. The energy consumption data information collected by the intelligent building system will be transmitted to the data concentrator for centralized processing of energy consumption data information and operation status such as electric energy meter, water meter, cooling meter and gas meter in the building. The concentrator will convert the data information into TCP / IP protocol packets. Under the action of firewall, the communication network will promote the operation of data information processing module and transmit the relevant energy consumption data information to the database. The data acquisition system manages the building terminal communication protocol in the concentrator and checks the errors in data communication regularly. Conduct relevant data processing for many contents such as data loss and abnormal work, effectively obtain relevant data information in the database, and dynamically monitor, evaluate, analyze, store and display the energy consumption in the building in combination with the energy consumption monitoring indicators set by the system. The monitoring terminal will generally obtain relevant data from the database and obtain the evaluation results for comprehensive analysis and control. The monitoring terminal will analyze the control instructions in combination with the database, data acquisition system, communication network, firewall, concentrator, etc., so as to control the data information status of the acquisition terminal of the building.

4 Key technologies of energy consumption monitoring system for large public buildings.

4.1 Multiple energy consumption acquisition terminal access technologies

 In the energy consumption monitoring system of large public buildings, one of the key technologies is a variety of energy consumption acquisition terminal access technology, so as to integrate and collect a variety of energy consumption in public buildings. There are different access technologies of multiple energy consumption acquisition terminals in different brands of energy consumption monitoring systems. How to connect multiple energy consumption acquisition terminals with one concentrator is very important. Because there are private protocols for different energy consumption monitoring systems, when selecting the energy consumption monitoring system of large public buildings, we should analyze the systems of different brands, clarify the private protocols and energy consumption collection and connection modes of each brand, and ensure that the energy consumption monitoring system developed by different brands can meet the actual use needs of large public buildings, Ensure that the software system can be smoothly connected to different energy consumption acquisition terminals.

4.2 System software development technology

In the actual application of large-scale public building energy consumption monitoring system, it is necessary to introduce the development technology of this software platform in combination with the overall framework and module layered characteristics of the system. With the help of Java, javascrip and other programming languages for program coding design, the data repository is connected with cloud storage technology to ensure the security and huge capacity of energy consumption data information storage. During data information transmission and communication, a stable RS485 data communication standard should be selected to ensure the high-quality operation of stored data information.

5 Introduction to ankerui energy consumption monitoring system

Acrel-5000 energy consumption online monitoring system is a user-side energy management and analysis system. Based on the electric energy management system, it adds centralized collection and analysis of water, gas, coal, oil and heat (cooling) capacity. By subdividing and counting all energy consumption at the user-side, it shows the use and consumption of various energy to managers or decision-makers with intuitive data and charts, It is convenient to find out high energy consumption points or unreasonable energy consumption habits, effectively save energy, and provide accurate data support for users' further energy-saving transformation or equipment upgrading. Users can implement energy audit in accordance with relevant national regulations, analyze the current situation, find problems, tap energy-saving potential, put forward practical energy-saving measures, and submit energy audit reports to the administrative department of energy conservation of the people's government at or above the county level.

5.1 Platform structure

Acrel-5000 energy consumption online monitoring system takes computers, communication equipment and measurement and control units as basic tools, and adopts one or more combined networking modes of fieldbus, optical fiber ring network or wireless communication according to the actual situation of the site, providing a basic platform for real-time data acquisition, remote management and control of large public buildings, It can form any complex monitoring system with detection equipment. It is open, networked, unitized and configurable, and adopts the object-oriented hierarchical, hierarchical and distributed intelligent integrated structure. Establish the following hierarchy:

Figure 3 platform structure

5.2 Platform functions

 (1) The system can count the energy consumption of each classification of buildings - electricity, water, gas, central heating, central cooling and other energy consumption according to the service year, and automatically convert it into the corresponding standard coal consumption, so as to reflect the energy consumption and comprehensive energy consumption of each classification of buildings in the current year. The system displays the proportion of the energy consumption of the four major power sub items of the building in the form of pie chart. The system shows the consumption trend of various energy consumption with curves and graphs, which is convenient for the owner to grasp the energy consumption in real time and intuitively.

(2) The system can query the energy consumption according to the branch name of classified energy consumption, and display the peak energy consumption of the current day and the current month. It shows the comparison of energy consumption of the current day, the current month, the current year and the same period of yesterday, the same period of last month and the same period of last year. The energy consumption in the past 48 hours, 31 days, 12 months and 3 years is displayed in a bar. The upper right corner shows the curve of the past 15 minutes (the electricity meter shows the power curve and the flow meter shows the flow rate curve).

(3) The system selects and sets energy consumption measurement points according to the distribution of building energy consumption, so that the energy consumption monitoring system can cover the whole building. The system user can access the energy consumption statistical report of each energy consumption node of the building through the relevant interface to reduce the "running, emitting, dripping and leakage" and measurement error of energy consumption.

(4) According to the guidelines for energy consumption data collection of sub items of residential buildings, the system divides the power consumption of buildings into lighting sockets, air conditioners, power and special power, selects and sets metering devices, divides and makes statistics according to energy consumption areas or functional areas, and displays the energy consumption of the area in the form of statements and comparison bar charts.

(5) The system can accurately locate equipment or areas with large energy consumption, so as to facilitate the management to formulate energy-saving performance evaluation system and promote the effective implementation of energy conservation and consumption reduction. Establish operation record files for key energy consuming equipment, track and record the energy efficiency analysis and evaluation results during equipment operation for a long time, and provide basis for equipment operation and maintenance in combination with equipment maintenance records.

(6) The system provides hierarchical authority management function and provides open information maintenance interface for users with authority. Users can add, delete, modify and query the information of buildings and measurement points within the monitoring range of the system. Building information includes building type, construction age, building area, number of building personnel, etc. The system also provides manual input function for measurement information that cannot be automatically collected, so that users can master the overall energy consumption of buildings.

5.3 Data upload

According to the requirements of the system platform interface protocol specification defined in the technical specification of the on-line monitoring system for energy consumption of key energy users, the on-line monitoring system for energy consumption of ankerui will upload the basic information, measuring instrument information, energy consumption data and energy efficiency data of energy consuming enterprises to the provincial or national platform, and the uploaded data will be encrypted and transmitted through HTTPS protocol. If the data transmission fails or times out (network failure), the data will be retransmitted until a successful feedback message is received.

5.4 Selection of energy meters

6 Conclusion

In a word, the energy consumption monitoring system of large public buildings has certain advantages, and can meet the current social green energy-saving development needs in the process of operation. Therefore, in combination with the current development needs of China's construction industry, we should actively innovate the energy consumption monitoring system and related equipment of large public buildings, improve the relevant supporting facilities of the energy consumption monitoring system, dynamically and timely analyze the energy consumption of large public buildings, timely find the problems caused by excessive energy consumption, and make targeted improvements, Truly implement the development needs of energy conservation and consumption reduction in China and the world.