For the medium and large central air conditioning system, we have launched self-operated differential pressure bypass and proportional integral differential pressure bypass solutions, which solve the problem that the flow through the medium and large chiller is constant, and the flow through the end is changed according to the load. The end water flow control of this scheme uses an electric two-way valve, and the energy between the ends can be transferred to each other.

Disadvantages of existing differential pressure bypass control

▶ The pressure difference controller is used to control the switch of the electric valve, because the pressure difference controller only has two states of on and off, the electric valve is always in the process of opening and closing, the life of the electric valve is greatly shortened, and the water flow through the end and the host is constantly changing, the host work is extremely unstable, and the host fails in serious cases.

▶ Can not perceive the current pressure difference value and the opening of the bypass electric valve, so that the whole air conditioning system is difficult to set the correct bypass pressure difference value, the pressure difference value is too large, the host flow is insufficient, the pressure difference value is too small, the bypass flow is too large, and the end can not get enough flow.

Benefits of differential pressure bypass control energy saving solutions

▶ Adopt self-regulated proportional differential pressure bypass valve, both ends of the bypass valve are installed with pressure gauges, you can refer to the pressure difference at both ends to set the differential pressure setting value of the bypass valve. The differential bypass valve adopts stainless steel valve shaft, brass seat and valve sleeve to ensure that the valve stem can be adjusted freely and the service life is longer. In order to normal water supply, due to the use of vertical scale, the user has only one adjustment point, will not cause misaction, the user set the indicated scale value is the water supply pressure.

▶ Adopt electric proportional integral control differential pressure bypass valve. An industrial capacitive differential pressure transmitter is installed in the inlet and outlet water main pipe to sense the pressure difference of the inlet and outlet water pipe. The pressure pressure of the transmitter is greater than 25bar, and the differential pressure signal is collected by the controller. The pressure difference value of the inlet and outlet pipe is precisely controlled at the set value.

Application of energy saving solutions for differential pressure bypass control

▶ For the differential pressure bypass we introduced two sets of solutions, self-operated proportional valve and proportional integral control electric valve, the proportional integral control is better in terms of performance, but the price is relatively higher, but the pressure differential bypass adjusted by the analog quantity can easily change the differential pressure setting value, and after debugging, it can ensure that the differential pressure bypass will not produce too large or too small bypass flow. It also plays a good role in protecting the host. At present, proportional integral control is more used in commercial buildings with a large number of terminals, and self-operated proportional valves can also be used when there is not much terminal equipment.