Frequency Conversion Control Cabinet
To promote energy saving and emission reduction, the Company developed its own smart energy-saving frequency conversion control cabinet independently in 2012; the product is capable of controlling running of fans according to pressure or temperature feedback signals, and effectively reducing evaporative condenser, closed cooling tower and other units’ energy consumption, thus providing the best energy-saving operation solution; the product has been awarded national utility model patent (patent number: ZL201320092910.8, certificate number: 3164279).
Its products and services are highly praised by domestic clients, as well as oversea clients from nearly 20 countries, such as the United States, Japan, Australia, New Zealand, Latin America, South America, Africa and Southeast Asia.
Frequency conversion cabinet is composed of control switch, electronic energy meter, Omron programmer, ABB frequency converter, small-sized contactor, AC contactor, motor protector, power inverter, built-in temperature control system, housing and ancillary components.
The frequency converting control principle is described as follows: pressure or temperature sensor is installed in inlet pipes of evaporative condenser/cooling tower to collect pressure / temperature parameters; when the collected pressure / temperature is higher than preset parameters, all the fans run at power frequency; when collected pressure / temperature is lower than preset parameters, the controller will enable the first fan via commands, reduce the power frequency of fan motor, thereby reduce overall air flow and cooling capacity. Thus，the temperature/pressure will be stable at a preset value. When the first fan power frequency is reduced to 50% of rated frequency, the fan power will be cut off, then the frequency converter will start to control the second fan; as long as the collected pressure / temperature is lower than the preset value, the frequency converter will reduce the operating frequency of fans one by one until the power is cut off.
When the ambient temperature is continuously changing, the control cabinet is capable to collect operating parameters automatically and take the necessary adjustments to make sure that the system is always running at relatively economical conditions, and bring significant energy saving effects, especially in winter or other lower-temperature seasons. In addition, the cabinet is provided with remote monitoring, motor protection and alarm functions, and thereby greatly reducing the probability of damage to all the motors.
Take YCB-7.5KW-4-D energy-saving control cabinet as an example: If the compressor’s discharge pressure is 12 Bar under economic conditions; condenser condensing pressure is higher than 12 Bar in hot summer, then all the fans run at power frequency; in spring, autumn or winter, wet bulb temperature decreases, when the condensing pressure is lower than 12 Bar, the frequency converter will decelerate the first fan to stabilize its condensing pressure to 12 Bar; if the pressure is still lower than 12 Bar after the first fan is decelerated and even stops running, the frequency converter will auto-switch to control the second fan; the rest fans can be controlled in the same manner, until the condensing pressure is stabilized at 12 Bar. Under the premise that the system is running well, the cabinet aims to save power energy by decelerating or stopping the fans.
Performances and features
1. Energy-saving and efficient. Available in frequency conversion and acceleration; through feedback signals from PID, the frequency converter of the product adjusts fans automatically to save energy, stabilize pressure or flow. The system is provided with independently-developed auxiliary devices, and can adjust automatically to the best energy-saving effects according to local climate and temperature.
2. Automation and reliability. Easy to operate and manage; the product is programmable in control, and its signal feedback device is under computer-based central control. A variety of protection features to ensure reliable running.
3. Cost savings. The product adopts single control unit to control at least two (or more) motors, thereby reducing number of motor control units in circuits effectively, especially frequency converters, optimizing the manufacturing cost of circuits, lowering the cost of motor control units doubly and even multiply, and avoiding waste of resources; Furthermore, motor control components such as frequency converters are adopted to control at least two motors (or more), thus to minimize losses of energy, and maximize energy saving effects of motor control circuits.