Weak current College】 【University teaching building of BAS in air conditioning system control --- Power By】 【China power house network.

<br> Overview <br> <br> A university teaching buildings as the National University campuses a flag-type building. Total construction area 70000 square meters, total height nearly 100 meters. 3rd floor, ground floor, floor 27 floors. The building's .basement for equipment room, car park, group of buildings into large classrooms, laboratories and graduate and multimedia classroom activities Hall and multi-function Hall, International Conference Hall and small and medium-sized meeting rooms; the main building for Office space. The building .will be built in a genuine high-tech, intelligent electronic system. Its BAS system uses United States Johnson METASYS building company management system for design, here on this system of air conditioning systems of control for details. <br> <br> 1. .this general architecture (BAS) <br> <br> According to the floor using features and design requirements, building automation management (BAS) system for air-conditioning units, fan group, refrigerating station system for monitoring, control, recording and alarm; .on the power supply system main parameters monitoring, recording and alarm; elevator inspection and alarm, water hole detection and control of sewage pump; lighting system for monitoring and management to achieve a comfortable, convenient, efficient and easy to manage. <br> < .br> The system is mainly composed of one operator station, 1 network controller DDC controllers, 24. As in the following diagram: <br> <br> Action stations-network controller <br> <br> This system can Ethernet network (N1 .Grid) to the central station and network controller to connect all nodes, while installed in buildings everywhere direct digital control (DDC) via the RS485-fieldbus (N2) connected to the network controller, and other network controller for direct digital controllers and Central operations .station closely. Sensors and actuators, connected to the direct digital control (DDC). <br> <br> 2. (BAS) on control of air conditioning systems <br> <br> This building air-conditioning system mainly includes the following .equipment: <br> <br> (1) combination type air conditioning unit 26, <br> <br> (2) air supply unit 31; 38 units blowers; <br> <br> (3) 1 a Cryo systems; .<br> <br> 2.1 air-conditioning unit of monitoring <br> <br> The entire building has a total of 26 sets combined air-conditioning unit. One layer 8, second floor 7, three-layer 3, layer 4 to .8, 5-layer 3. Air conditioning unit for the comfort of air conditioning units, designed for meeting rooms, offices and classrooms provide comfortable and high quality air. The air treatment for: outdoor fresh air by fresh air valve adjustment after the initial result .of the filter and return air mixed preheating section, table, cold heating period, after being fed into the forced draft fan filters. <br> <br> Need to monitor as follows: <br> <br> Back to duct air temperature ( .AI) <br> <br> Fan monitoring (DI) <br> <br> Fan fault alarm signal (DI) <br> <br> Automatic or manual status display (DI) <br> <br> Fan switch control ( .DO) <br> <br> Fresh air throttle control (AO) <br> <br> Two-pass water valve control (AO) <br> <br> Indoor temperature (AI) <br> <br> Indoor humidity ( .AI) <br> <br> Indoor static pressure differential (AI) <br> <br> In the action stops, each air conditioning unit will show through color 3D graphics, intuitive representation of different air conditioning unit running status and alarm signal, .dynamic displays each unit's operational status, fault status, return air temperature, and individual air conditioning units scheduled commitment control, and can be modified by the mouse settings or terminal device opening, change the device status, and stopping in order to achieve optimal working environment .. <br> <br> The air conditioning unit from METASYS system on a daily pre-scheduled time, including the holiday program for air-conditioner unit monitoring and control. <br> <br> 2.1.1 air-conditioning unit of water .valves and air supply valve control <br> <br> Water valve control is based on the return air temperature sensor feedback temperature signal, adjust the hot and cold water valve to open degree, so that the air temperature trend setting temperature (PI ratio adjustment .); when the air temperature is higher than the set temperature, DDC auto output gateway signal, turn the hot and cold water valve, while open hot and cold water valve, thereby meets the set requirements for the indoor temperature to prevent the temperature is too .high, too low to inconvenience people work, and the biggest energy savings. According to General experience, there is no loading valve before valve opening is 85 per cent, with adjusted control valve, the valve opening is only 40% ~ 60%, therefore .can reduce energy consumption. <br> <br> Regulation of outdoor air valve to control the main use for the following three areas: (1) save energy. On fresh air valve for regulation to ensure the maximum utilization of fresh air. When the .outdoor air temperature near the indoor temperature, outdoor air valve open all; when the outdoor air temperature compared with the set temperature, the temperature differential is too large, you only need to ensure that the minimum ventilation rate, will close the air supply valve to .the minimum position, maximize return air. (2) protection of fans, due to local air quality, fresh air valve is normally open status, filters easy dirty, needs regular cleaning. Therefore you need to implement the fresh air valve and fan of chain ., when the fan is closed, the door closed automatically, preventing dust to enter. (3) in each of the rooms are equipped with multiple indoor static differential pressure sensor, can detect Interior and external environment for static differential pressure difference under hydrostatic and set .value comparison between to determine ventilation opening, so that the work of the Interior in an optimal learning environment. <br> <br> 2.2 air supply unit monitoring <br> <br> The entire building has a total of 31 sets of air supply .unit, responsible for second-level 1, level 1, 1, 2, 4 layers, three-layer 2, 5-layer 4, 7-26-1 per floor mainly for rooms with high-quality fresh air. The air treatment for .: outdoor fresh air by fresh air valve, by early filter, cooling heating period, each floor after Fed forced draft fan room. <b> </ b> R> <br> Monitoring of the content is as follows: <br> < .br> Air duct temperature (AI) <br> <br> Fan monitoring (DI) <br> <br> Fan fault alarm signal (DI) <br> <br> Blower automatic or manual status display (DI) <br> .<br> Fan switch control (DO) <br> <br> Fresh air throttle control (DO) <br> <br> Two-pass water valve control (AO) <br> <br> Outdoor air temperature (AI) < .br> <br> Air temperature (AI) <br> <br> In the action stops, each air supply unit are displayed by color 3D graphics, intuitive display different air supply unit's operational status and alarm signals. Dynamic display each unit's operational status ., fault status, the air temperature. At the same time, individual air supply unit scheduled commitment control, to achieve the best possible work environment. <br> <br> METASYS system air supply unit from the day of the time including pre-scheduled .holiday program on unit for monitoring and control. <br> <br> 2.3 equipment selection: <br> <br> (1) air duct temperature sensors-selection TE-6321P-1, it is a resistance temperature sensor, and General Electronic .temperature sensor compared to the advantages of low price, you can apply directly to the DDC signal transfer. <br> <br> (2) fresh air valve drive-use M-9116-GGA Proportioning Valve drive, you need to make a fresh .air ventilation valve stem in order to facilitate the valve to drive installation. <br> <br> (3) control valve and valve drive-select double DO valve and drive, its biggest advantage is completely satisfy the humidity PID, while normal Proportioning Valve .(AO valve), can save AO point (because the General controller, AO points less) at the cost of cheap 10 per cent to 30 per cent. <br> <br> (4) the pressure differential switch-selects P233A-10 .-AKC differential pressure switch, the product structure, lightweight, inexpensive. <br> <br> 5) outdoor temperature sensors-selection TE-6323P-1 resistive temperature sensor, the choice of two temperature sensors, located on the third floor of the .South and North, averaged temperature value, then the numerical transmission across the network to each air conditioning units of the DDC. <br> <br> (6) DDC controllers-selection DX-9100-8154, 8DI, 6DO, 6AI, 2AO ., DX-9100-8454, 8DI, 6DO, 6AI, 8AO so that you can save a lot of wiring work, and has a high price / performance ratio. <br> <br> 2.4 refrigerating station monitoring <br> <br> .The entire system consists of four chillers (three with one slave), six sets of frozen water pump (four with two preparation), an expansion tank, four cooling towers, water separator and set water dispenser, six-bed cooling water pump. < .br> <br> Refrigerating station system monitoring: <br> <br> Monitoring of cooling water supply and return water temperature (AI) <br> <br> Monitoring the chilled water supply and return water temperature (AI) <br> < .br> Monitoring the temperature of the chilled water backflow (AI) <br> <br> Monitoring the chilled water supply and return water pressure difference (AI) <br> <br> Control of pressure differential bypass valve (AO) <br> .<br> Frozen water pump running status, fault alarm, automatic State (DI) <br> <br> Heat pump operation status, fault alarm, automatic State (DI) <br> <br> Cooling fan running status, fault alarm, .automatic State (DI) <br> <br> Chiller operation and fault alarm, automatic State (DI) <br> <br> Expansion tank of high and low liquid alarm (DI) <br> <br> Fill the pump running, .fault alarm, automatic State (DI) <br> <br> Flow of frozen water (DI) <br> <br> Cooling water flow (DI) <br> <br> Chilled water pumps, cooling water pumps for start-up .and shut-down (DO) <br> <br> Chiller and stopping (DO) <br> <br> Cooling fan for stop-and-control (DO) <br> <br> Cooling water intake electric butterfly valve control ( .DO) <br> <br> Chilled water inlet electric butterfly valve control (DO) <br> <br> Cooling tower water electric butterfly valve control (DO) <br> <br> Cooling water pump and frequency control of chilled water pumps .(AO) <br> <br> By installing the engine in the frozen direct digital controller DDC according to the internal prewritten software program to control the start and stop the condenser and the associated device group control. <br> <br> Detection devices .running status, fault status, fan for start-up and shut-down control. In the action stops, each electromechanical equipment through color 3D graphics display, the icon changes color and blinking, visualize different device running and alarm signals. <br> < .br> Refrigerating station system by METASYS system on a daily pre-scheduled time including holiday program on cold station system for control and monitoring. <br> <br> 2.4.1 refrigerating station main equipment monitoring <br> <br> (1) .testing various mechanical and electrical hand automatically. Power larger equipment, for security considerations require additional hand automatic transfer switch, when hitting the manually, automatically does not work, this allows the system to debug and maintenance or emergency. <br> <br> ( .2) detection of frozen water of the temperature and the backwater back into water. According to the supply / return water temperature difference and back to the water flow to adjust UNTIS run number, while the corresponding circulation pump and cooling chain and stopping. <br .> <br> (3) according to the program or work schedule automatic switch refrigeration unit. Through the program control refrigeration unit, minimum power consumption, achieve minimum host of depreciation. <br> <br> (4) freezingWater supply water pressure difference ., at the same time back in chilled water for water mains (or set of water and water separator) install the pressure difference between the bypass valve. When frozen pipes for back pressure differential over the set value, the pressure differential bypass valve from opening automatically ., DDC adjust its opening, the pressure differential for back to meet the set requirements, preventing pressure too high and damage to the freezer. Thus ensuring freezer side of frozen water of a constant, guarantee the security of. refrigerator <br> <br> .(5) detection of high and low level of expansion tanks. When the expansion tank level below low liquid level switch, DDC control fill the pump-water supplement expansion tank, when the level reaches high level switch, invigorating water pump stops. <br .> <br> (6) when the cooling water, chilled water flow switch monitoring the water flow through the cooler are allowed to start, preventing the cooler air load operation, resulting in damage to the freezer. <br> <br> (7 .) on the frozen water of the water, cooling water electric butterfly valve control, reducing the system load. When the system opens a cooling machine, simply open a cooler cooling water, chilled water supply valve control. The opening of the unit's cooling water, .chilled water valve, while the butterfly valve the unit off. <br> <br> When a chilled water pumps, cooling water pumps or invigorating water pump fails, the standby pump will automatically be put into operation. <br> <br> ( .8) the start and stop programs of linkage equipment including an adjustable delay time feature to match the frozen system device characteristics. <br> <br> (9) detection of cooling water supply and return water temperature. When the temperature is higher than the .set value 37 degrees centigrade, the cooling fan to automatically start when you are not satisfied then start the next Tower until you meet up with the set temperature; when the temperature is lower than the set value 25 ℃, the cooling fan automatically shut down the .computer, temperatures also low, and close the next Tower until meet the use temperature setting. This will maximize the savings fan running time, reduce energy consumption. <br> <br> (10) for the cooling tower water, electric butterfly valve control .to reduce the load on the operating system. You only need to install the butterfly valve, inlet install General floating ball Tower for water control control. Because the cooling tower connected vessels belonging to an open, each level that was not vacuumed or filled, install .water inlet valve is optimized for cooling water pump start-up and shut-down control. <br> <br> 2.5 heat transfer station system <br> <br> The entire building by two exchanger unit provides heat, the heat transfer station system .including two heat unit, and cooling systems, the total of six sets of circulating pumps (four with two preparation), water separator, water, and an expansion tank. <br> <br> Heat exchange station system monitoring: <br> < .br> Monitoring two hot water supply temperature (AI) <br> <br> Detection of water pressure (AI) <br> <br> Hot water supply in the current state (DI) <br> <br> A hot water supply ., electric butterfly valve switch control (DO) <br> <br> Second hot water supply, electric butterfly valve switch control (DO) <br> <br> Other monitoring content with cold station system. <br> <br> By installing .the engine in the frozen direct digital controller DDC according to the internal prewritten software program to control heat device group control. <br> <br> (1) according to the program or work schedule automatic switch exchanger unit access water valve. Program control exchanger .unit, in order to achieve the lowest power, lowest host of depreciation. <br> <br> (2) to specify the pipeline location setting temperature sensor to measure the temperature of the chilled water for backwater. <br> <br> ( .3) when the expansion tank level below low liquid level switch, DDC control fill the pump-water supplement expansion tank. <br> <br> (4) when the hot water pipe flow switch monitoring the water flow through the circulation pumps are allowed .to start, preventing their empty-load operation. <br> <br> (5) the start and stop programs of linkage equipment including an adjustable delay time functionality to meet the thermal station system device characteristics. <br> <br> Closing remarks .<br> <br> Use the BAS, for air conditioning system has the following significant advantages: <br> 1. energy savings: <br> 2. Save on administrative costs: <br> 3. extend equipment life: <br> .4. improve management reliability: <br> 5. makes management standardization: <br> <br> BAS itself can be based on the management practices of the automatic control, automatic analysis of personnel management directive, makes some of the non-canonical management .standardization. <br>.