The design of ventilation automation system for warehouse
The storage facility object completed by us in terms of design, installation and commissioning of the automation system for general ventilation.
DESIGNING OF VENTILATION AUTOMATION
Considering the main purpose of the building, the project provides for the possibility of further expanding the network for dispatching and automation of engineering equipment. Additional control and monitoring panels with the necessary equipment may be located in the technical premises of the complex as the need arises to automate new systems.
This project includes:
- automation of ventilation systems of the engineering building;
Structurally, the automation system is a network of control, freely programmable controllers installed in the boards (together with the power unit) at the place of installation of this or that equipment.
The connection between controllers and external devices (drives, sensors) is carried out with the help of shielded cables, such as MKESH 2x1.0, 3x1.0, 4x1.0, the shields of which are properly grounded in order to avoid induced currents. The cabling of the automation system is carried out in separate metal trays, at a distance of at least 200 mm. from power wiring, and from trays to units in a metal corrugated pipe with a diameter of 16, 20, mm.
In addition to remote and automatic control of units, provides for "local" control, directly from the control panel; In addition, the project provides for installation of safety switches at the place of installation of units that are remote from the panel (pumps, general ventilation fans).
2. Basic automation solutions using Honeywell equipment.
2.1 To solve the problems of automation of the ventilation system, the project uses a complex of tools from Honeywell.
The complex includes:
- primary converters with unified output signal 0 ... 10V
(air temperature sensor, water (liquid) temperature sensors;
- differential pressure sensors with discrete output signal;
- drives of water valves and air dampers;
- freely programmable, multifunctional microprocessor controllers EXCEL 500;
- the device of communication of the personal computer with controllers - BNA;
2.2 In the premises of the placement of ventilation systems, the installation of electrical panels with built-in controllers is provided.
2.3 Systems management provides 3 modes:
- Local control of electric motors of fans, pumps from control panels.
- Remote control (from the CDP premises)
- Automatic systems management.
2.4 Automatic control is carried out according to a predetermined program embedded in the controller.
2.5 In order to transfer the unit or the entire system to local control mode,
it is necessary to switch the corresponding switch or all switches on the control panel to the “On” position.
Local control mode should be used only when debugging systems and in case of emergency.
2.6 Automatic control panel with EXCEL500 controllers provides:
- start in work in a certain combination and sequence of all units of the system;
- implementation of the necessary laws of regulation and management, blocking dependencies;
- the inclusion of a backup pump motor when a worker fails;
- measurement of current parameters and transfer of their values to the CPD;
- control of the state of the equipment (enabled / disabled, accident);
- remote on / off systems from the CPD;
- transfer to the CPD of emergency and statistical information about current technological processes.
3. Solutions for automation of ventilation systems.
3.1. To solve the problems of automation of ventilation, a complex of means is provided with the use of combined electric switchboards of control and automation. The complex includes:
- electrical control panels and automation with built-in controllers, located at the place of installation of the equipment they serve. The power characteristics of the general ventilation ventilation boards are as follows:
~ 380 V, 50 Hz, according to the 2nd category of power supply reliability,
- bus information exchange between controllers (C-BUS), physically representing a two-wire communication line.
3.2 Automation of engineering building ventilation systems includes:
- Management of ventilation systems (on / off) from the workplace of the dispatcher or automatically according to a temporary program.
- Control of the supply (exhaust) fan in automatic mode with observance of all necessary interlocks and dependencies, such as - blocking due to the absence of differential air pressure on the fan, danger of freezing the heat exchanger (according to a signal from the thermostat of low air temperature behind the heat exchanger), low temperature of the return heat carrier.
- Control of the circulating pump in the automatic mode - changing the mode of operation of the system by the operator from the central computer depending on the season, or in the automatic mode according to the readings of the outdoor temperature sensor.
- Control of the valve actuator on the coolant in automatic mode, observing all the necessary interlocks, such as opening the valve 100% with the threat of freezing of the heater, closing the valve when changing the season from "winter" to "summer". In the operating mode, the controller controls the valve depending on the air temperature in the room served by the supply system. Through its opening or closing, the supply air temperature varies according to a schedule from +13 to + 29◦С, depending on whether it is necessary to heat the air in the room or cool it to the setpoint set by the operator. To accurately maintain the air temperature in the room, the PID control law is used in the valve control program.
- Disable ventilation when a fire alarm signal is received from the fire alarm system on the ventilation control panel. Each ventilation control panel provides for the connection of an external signal from the PPP. Shutting off consumers of a shield, in order to increase reliability, is carried out at a “relay level”, i.e., even when consumers operate in manual or remote mode, they must be guaranteed to shut off.
3.3 Dispatching of ventilation systems provides:
- obtaining information about the temperature of the supply air;
- obtaining information about the temperature of the supply and return coolant;
- obtaining information (in graphical form on the CDP monitor) about the presence of pressure drop on the fan (supply and exhaust);
- obtaining information (graphically) on the presence of pressure drop on the filter;
- obtaining information (in graphical form) on the operation of a low-temperature thermostat behind a heat exchanger;
- obtaining information on the receipt of a signal about the fire of the control of ventilation from the fire alarm station (hereinafter PPP);
- obtaining information on the position of fire dampers (graphically).
- obtaining other statistical, preventive and emergency information.