Change the pump speed ：
Pump performance parameters are relative to a certain speed, when the speed changes, the performance parameters of the pump will change. When the fan coil unit system from the design load to part of the load, the total water supply will be reduced from the design flow to the running flow, this time can be changed by changing the speed of the pump to achieve this purpose.
Variable speed regulation and valve adjustment compared to the addition of no throttle loss, but also because the water pump power consumption is reduced by the 3 party relations, and makes the energy saving effect is significant, and the stability is good.
Variable speed regulation can be divided into the use of multi pole motor speed control and the use of frequency converter and other speed control device of the stepless speed regulation. It should be noted that the speed adjustment of the pump when the minimum speed should not be less than 50% of the rated speed, the general control in 70% ~ 100% between. Otherwise, the pump's operating efficiency is too low, resulting in excessive power consumption may be offset by reducing the speed of the energy saving effect. In addition, the output power of the motor is too much lower than the rated power, or the operating frequency is too much lower than the rated power frequency, will greatly reduce the efficiency of the motor. When the induction motor is driven by the inverter, the current of the motor will be increased by about 5% compared with the rated power frequency.
If pump had not equipped with speed control device, equipped with when it is necessary to pay attention to two aspects: one is the water flow of fan coil system generally in more than 90% of the rated flow of water pump change, do not need the speed control device. Because the speed control device itself is about 90% efficiency, at this time will not generate much energy efficiency, but will increase the energy consumption in close to 100% traffic operation. With speed regulating device will increase investment in equipment, to small capacity of pump is necessary, should technical and economic analysis and then make a decision. It is generally believed that within two years from the energy saving investment recovery can be configured.
The chiller artificial cold source, most are in a chiller correspond with a chilled water pump and a cooling water pump, so when a considerable potential for energy conservation, the variable speed operation is the most easy to achieve, and the operation and management are the most simple.
