【 Weak current College 】 intelligent building air-conditioning automatic control system design-Power By 【 China power house network 】

Intelligent building is the use of system integration method, intelligent computer technology, communications technology, information technology and organic combination of architectural technology, through the device of automatic monitoring, for efficient management of information resources, to provide adequate information services, technical and architectural perfection, so that the owners of the investment, and have a safe, efficient, comfortable, energy-saving, convenient and flexible high-quality environment. Intelligent building is the information society and globalisation is the inevitable outcome, multidisciplinary, integrated high-tech's ingenious, it will become the mainstream of development in the construction industry, its essence is through the integrated configuration structures within the functional subsystem for structured cabling system as a platform to computer network system for bridges, the entire building of efficient management, control, and share.

Air conditioning system in the building's total energy consumption in very large. Therefore, ensure a comfortable environment to people, to reduce the energy consumption of air conditioning system, air conditioning system become intelligent building control system an important and essential part. There are statistics, BA system uses the optimal operation of the device number of the control, optimal start and stop control, enthalpy value control, face illuminance control, public area partition automatic lighting control, water supply system pressure control, temperature control and other energy-saving measures can reduce energy consumption by about 20% and, therefore, these initiatives have very important implications.

At present, China's most buildings with conventional air conditioning system is still on the air conditioning system of instruments for monitoring, control and management. As computer technology, information technology and the rapid development of automatic control technology, as well as in HVAC applications, use of the extensive system integration method instead of the traditional instruments, meters, can more effectively control the air conditioning system, improve the performance of air-conditioning system saving energy consumption. While also reducing operational management and administrative personnel's labor intensity. The following works for the author's work, for instance air-conditioning automatic control system design methods for quick analysis.

1. the objectives of the system construction

Building automation system (BAS) design quality is good or bad, is the entire building intelligent structure can truly embody their intelligence and reliability of one of the important factors. Users need more than just a suitable and reliable system, it also should be a combination of openness, flexibility and expandability of advanced systems. Thus, we use from the architectural point of view, in-depth understanding of user needs, improve system design, efforts to make the system meet ① efficient save energy. On the whole floor, air conditioning equipment for monitoring, managing device power consumption of the different period of time so that the system devices always in top running condition, reduce unnecessary waste and to achieve the purpose of saving power. ② substantial savings in manpower. Equipment for simple operation, maintenance, maintenance is to a large number of artificial completed, this work is done automatically by the system control program. ③ extend equipment life. Devices in the system process control, always in top running condition, promptly report equipment fault conditions and treatment, in accordance with running state of printing equipment maintenance report, avoid advance or delay, the appropriate extended equipment maintenance service life, efficiency. ④ security architecture and personal security, system monitoring, but running watch timely detection of failures, problems and accidents, elimination of failures in risk, exclude accidents in prevention, security architecture and security of person.

2. system composition

Building equipment and automatic control (BAS) is a modern computer network technology, control technology, sensor technology and other high-tech product of effective medicine and, therefore, the system can network, control and sensor components and software in three areas.

2.1 network introduction

(1) Web standards and Internet way

Intelligent control system for the use of today's latest I/A system that uses the control bus and now bus level network structure of distributed control systems, use of BACnet and LonMark are open standards communications protocol, so that different systems integration easier.

Control bus connection system file server, monitoring station, a computer system used to work on-site monitoring and field data rollup process saved. Fieldbus connection digital direct controller (DDC), intelligent sensors and actuators for on-site equipment of control and regulation. While the control bus and field bus, use the network bridge (NGS-ETHERNET) Internet, on-site data feed and manual instructions for download. Network bridge can be arranged by data classification, may also be redundant. Control of bus communication speed up to 10Mbps, field bus communication speed up to 78.8kbps.

(2) system structure

The overall management and operations leads the monitoring station, take the overall coordination and management, distributed in various parts of the DDC controller directly with the device connected to the site, the predecessor to install, and on the connected device implementation monitoring and control, the actual realization of DCSC (distributed control). At the same time, I/A system available mobile laptop on controller programming online an in-place nearby, in the network of observation and operations on the node on the network in any of the controller, the system ofdebugging, maintenance and operation and maintenance offers great convenience.

In addition, Lonworks, communication interface, you can easily and building the electromechanical equipment and systems (such as elevators, lighting, energy management, gas, etc.) of network communications, data to arm.

All of the information passing through onsite network, without a computer, central control room of the computer is turned on or not and is not related to the work of the DDC controllers, and does not affect the normal operation of BAS system, avoiding computer centralized control of the risk posed by the concentration. Because of the Fieldbus Communication Protocol using Lontalk, point-to-point communication enables incident action response time significantly shortened, for building control implementation provides a reliable guarantee.
R > 2.2 control and sensor devices

The building control and sensor equipment adopts United States JCI products, this article does not make the introduction.

3. air conditioning equipment management automation

3.1 this building a/c overview

3.1.1 integrated building construction area 45000 square meters, floor 14 layer (local 16 layers), ground floor. Building total height 66 m, is a comprehensive office building, North through the Hall and Auditorium.

Auditorium building area of 2000 square meters and can accommodate up to 1000 people meet and satisfy the needs of medium and dances.

3.1.2 the mansion in HVAC in the following ways, all with air-conditioning. Office building lobby, Conference reception room and report the hall full air conditioning system, the rest are fan-coil air conditioners. Room with three-speed switch control air.

3.1.3 summer cold source electric cooling chillers, winter heat utilization outside the network provided by the Park's plate heat exchanger, supply air conditioning system.

3.1.4 freezing room and uniform heat transfer station is scheduled to set Office building's basement.

3.2 this building of cold, heat source system basic monitoring follows table



3.3 heat system for automatic start and stop order

Open order: hot and cold water valve, cold and hot water pumps, hot and cold water flow switch signal, chiller start.

Close order: chiller, cold and hot and cold water pump flow switch, hot and cold water valve closed.

4. concluding remarks

BA systems engineering field has the following problems:

1) BA system equipment in the domestic manufacturers provide uncommon products.

2) BA systems engineering quality is not high, many reasons, such as design flaws, contractors, owners implementation capacity low purchasing devices that do not implement the interface configuration and BA system acceptance no uniform standards, how to improve the quality of BA system, to be our common efforts.

3) through the design of this project, I feel that to do an intelligent buildings air conditioning

System of automatic control system design and construction must be in different stages the following several aspects:

① actively involved in the project stage design, and implement user-controlled system for more specific needs.

② Learn more about the control object (equipment, the subsystem), performance parameters, control interface and controlled;

③ establish economic and reasonable, energy-saving system control block diagram.

④ Select reliable automation products, supporting air-conditioning equipment do detailed ordering instructions, and manufacturers cooperate to avoid automatic control equipment and air conditioning equipment is not necessary.

⑤ on professional equipment of control, the professional must complement each other, to avoid leaking selected phenomenon and automatic control equipment cuoxuan.

⑥ improve system integrators of deepening the design, installation, commissioning and maintenance of security capabilities.

⑦ perfection on automatic control system design, construction and acceptance criteria and specifications.