Application of the hottest sanch frequency convert

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The application of sanch inverter in the energy-saving transformation scheme of air conditioning

for central air conditioning, according to the national standard, the maximum load capacity of the system is designed according to the working environment with the highest temperature and load. As far as the system itself is concerned, there is a lot of reserve space, but in fact (2) the system with good strength rarely works under these limit conditions. According to relevant statistics, the central air conditioner operates under 70% load in 97% of the time, so the actual load can not reach the full load (that is, the "big horse pulls the small car"), especially when the demand for air conditioning is small, the load of the main engine is the lowest

in order to ensure better operation status and higher operation efficiency, the host can reasonably load and unload according to the load change within a certain range, and the matching cooling water pump and chilled water pump will not be allowed to operate under high load all the time, so as to improve the cooling water of the central air conditioning. The operation efficiency of the chilled water system is low, and reduce the working time of equipment with large energy consumption and long operation time. Therefore, It is absolutely necessary to carry out energy-saving technical transformation of central air conditioning

features of energy-saving control system:

▲ the sanch-s3000 series central air conditioning electric cabinet is used to control the water pump motor. The software configuration and parameters can be set for PID adjustment as required, so that the motor output power changes with the change of thermal load, and the maximum energy saving can be achieved on the premise of meeting the use requirements

▲ due to speed reduction operation and soft start, the impact of current on the motor and the vibration, noise and wear of the equipment are reduced, the maintenance cycle and service life of the equipment are prolonged, the MTBF (mean time to repair) value of the equipment is increased, the impact on the power grid is reduced, and the reliability of the system is improved

▲ advanced setting, monitoring and adjustment functions improve the system operation characteristics and make the system easy to use

▲ the system has various protection measures (overcurrent, overvoltage, overload, overheating, motor phase to phase and short circuit to ground, etc.), and the system has bit (self detection) function, which greatly improves the operation rate, safety and reliability of the system

▲ the system can be controlled automatically or manually, and can be operated in power frequency or energy-saving mode. When necessary, the energy-saving system can be switched to the original system control mode without affecting the normal operation of the original system There is a problem with the software of the experimental machine; Use

▲ the annual average energy-saving rate of the energy-saving system shall not be less than 30%

according to the working principle of fluid transmission equipment water pump and fan, the flow (air volume) of water pump and fan is directly proportional to their speed; The pressure (head) of the water pump and fan is directly proportional to the square of their rotating speed, while the shaft power of the water pump and fan is equal to the product of flow and pressure, so the shaft power of the water pump and fan is directly proportional to the third power of their rotating speed (i.e. directly proportional to the third power of the power frequency). According to the above principle, reducing the rotating speed of the water pump and fan can reduce the power of the water pump and fan more. For example, if the power supply frequency is reduced from 50Hz to 45Hz, then p45/p50= (45/50) 3=0.729, that is, p45=0.729p50 (P is the motor shaft power); Reduce the power supply frequency from 50Hz to 40Hz, then p40/p50= (40/50) 3=0.512, that is, p40=0.512p50 (P is the motor shaft power)

it can be seen from the above that a large amount of electric energy can be saved when using S3000 series frequency converter for flow (air volume) control. The central air conditioning system is designed according to the maximum cooling capacity demand on site. The door and cover shall be easily loaded and unloaded. The cooling pump and refrigeration pump shall be considered according to the maximum working condition of a single equipment. In actual use, more than 90% of the time, the cooling pump and refrigeration pump work under non full load. The use of valves and automatic valves not only increases the throttling loss of the system, but also causes the whole air conditioning system to work in a fluctuating state because the regulation of the air conditioning is phased; This problem can be solved once and for all by installing a frequency converter on the cooling pump and refrigeration pump. It can also realize the automatic control of overshoot and recover the investment through frequency conversion energy saving. At the same time, the soft start function and smooth speed regulation characteristics of S3000 series frequency converter can realize the stable adjustment of the system, stabilize the working state of the system, and prolong the service life of the unit and network management

therefore, the variable flow air conditioning water system, which changes the amount of water with the heat load, shows great advantages and is more and more widely used. The SPWM Frequency converter is used to adjust the pump speed, which can easily adjust the water flow. According to the feedback signal of the load change, the PID regulator and the frequency converter form a closed-loop control system, so that the pump speed changes with the load. In this way, energy saving can be realized, and the energy saving rate is usually more than 20%. The power saving rate of the transformation is closely related to the user's use. Generally, the power saving rate in spring and autumn is higher, up to more than 40%. In summer, due to the large power required by the user, the space saved is limited, generally about 20%

transformation scheme

S3000 series frequency converter, temperature sensor and PID intelligent temperature control instrument are used to form a control unit, in which the cooling water pump and chilled water pump adopt automatic closed-loop temperature regulation, that is, the temperature sensor is used to sample the temperature of cooling water and chilled water, which is converted into an electrical signal (generally 4-20mA, 0-10V, etc.) and then sent to the PID intelligent temperature control instrument, The PID intelligent temperature control instrument compares and calculates the signal to determine the output frequency of the frequency converter, so as to change the speed of the chilled water pump and the cooling water pump, so as to achieve the purpose of energy saving. Variable frequency drive of cooling tower fan: the temperature sensor controls the frequency converter to drive the fan according to the return water temperature signal to make the fan work in the most economical state and save a lot of power

in the cooling water circulating system, the temperature difference between the return water and the outlet water reflects the heat to be exchanged; According to the temperature difference between return water and outlet water, the speed of heat exchange is controlled by controlling the speed of return water, so as to achieve the purpose of power saving on the premise of meeting the cooling needs of the system. A large temperature difference indicates that the refrigerating unit generates a large amount of heat, so it is necessary to increase the speed of the cooling pump, increase the circulation speed, and accelerate the cooling of the cooling water; The small temperature difference indicates that the heat generated by the refrigerating unit is small, which can reduce the return speed of the cooling pump to save electric energy

in the refrigeration circulation system, since the outlet water temperature is relatively stable, only the return water temperature can reflect the room temperature, so the temperature sensor can be controlled according to the return water temperature. The high return water temperature indicates that the room temperature is high, so the speed of the refrigeration pump should be increased to speed up the circulation of the chilled water; Otherwise, the low return water temperature indicates that the room

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