Application of Flow Switch in water circulation ground source heat pump system

Application of flow switch in water circulation ground source Heat Pump

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Water circulation and ground source heat pump unit is a rapidly developing type of air conditioning. It is widely used in office buildings, shopping malls, residential buildings and other occasions.  due to its application flexibility and high efficiency and energy saving. For the water loop heat pump unit, a large water loop heat pump system can be composed of a cooling tower and a low-level heat source. Generally, such a water circulation heat pump system, it will include less than a few hundreds water circulation heat pump units. Such a huge system requires very strict hydraulic balance of the water system. Otherwise, some water circulation heat pump units will not get the water flow required by others, which may lead to During the operation in summer, the refrigeration system often has too high condensation pressure and the unit starts and stops frequently, resulting in compressor failure. During the operation in winter, the excessive heat absorption of the heat exchanger due to the too small water flow may cause the internal freezing of the heat exchanger, thus causing the "tube explosion" of the casing heat exchanger.

In order to ensure the proper water flow of heat exchanger, in addition to the careful optimization design and hydraulic balance of the water pipeline, a water flow switch must be set to ensure that the compressor stops after the water flow stop, which is a very important protection device. If the water flow switch is not installed on each unit, it may cause the "pipe burst" of heat exchanger and compressor failure. Due to the large water system of water circulation heat pump, for the consideration of energy saving and stable operation of the system. the water resistance of each component in the water circuit is required to be small, so the water resistance of water flow switch cannot be too large. At present, the commonly used types of water flow switch are differential pressure type, paddle type and other flow switches,

The differential pressure water flow switch is designed according to the curve of resistance and flow of HVAC equipment. We know that the heat exchanger of HVAC equipment has its performance curve of resistance and flow. By detecting the difference of inlet and outlet water pressure at both ends and comparing with the preset value of the device, the flow can be accurately controlled.

Compared with the target paddle type flow switch, the differential pressure type is a better choice for flow control, which has accurate flow control value. It is directly installed in the unit to avoid incorrect installation by users. If two copper pipes are connected from the differential pressure switch to the inlet and outlet of the heat exchanger in the unit, the differential pressure at the inlet and outlet shall be measured to reflect the flow. However, the user does not need to install and wire at the site, which avoids the hidden danger of unit failure caused by inaccurate installation of target water flow switch.

GE-511C Differential Pressure type flow switch with stainless steel body

GE-511C differential pressure switches adopt stainless steel material,...

The differential pressure type flow switch has the characteristics of accurate flow control, no additional resistance to the system, no requirement for pipe diameter, and no disturbance of water flow. It can replace any type of target type flow switch as the flow control of HVAC water system. Compared with the target type flow switch, it can avoid the false flow caused by pump cavitation (the actual flow rate is large, but there is air mixed in the water However, the actual flow rate is not large), so it can be widely used in the control of water flow rate of water circulation / ground source heat pump units with brazed plate heat exchanger and sleeve heat exchanger, and it also has the function of partial antifreeze protection

GE-511A Differential Pressure type flow switches

GE-511A Brass body is Pressure Differential Switch with adjustable set.

According to the feedback of using in water circulation / ground source heat pump unit, the differential pressure switch can effectively judge the problem of the water pipe installed on the site of the water ring heat pump unit, and can completely avoid the situation that the heat exchanger is frozen due to the small water flow, and can also protect the situation that the heat exchanger is frozen due to the decrease of the water flow caused by the blockage of the water filter. In addition, the differential pressure switch of the water pipe has no target flow switch's paddle fatigue The risk of failure, especially when there is a small amount of air in the water pipeline, the differential pressure switch works very stably, and it will not float like the target flow switch. After years of use feedback, no fault is found in the differential pressure switch itself.