Application of Differential Pressure Flow Switch in Water Source Heat Pump System
September 11 10:06:02, 2022
Water source heat pump unit is currently the most rapidly developing type of air conditioning, which is widely used in office buildings, shopping malls, residential and other occasions with the application of flexibility and energy-saving features. For the water source heat pump unit can be combined with the cooling tower and low heat source to form a large water source heat pump system, water source heat pump unit is divided into two types of water - air and water - water source heat pump is obtained from the water cold and heat, so flow After each water source heat pump water flow and design flow consistent in order to ensure the unit cooling capacity and heating capacity, but also a reliable unit work an important condition, if you can not ensure that the appropriate flow rate will likely lead to high condensing pressure and the unit frequently start and stop , Resulting in failure, the following to ensure water source heat pump water flow method for an introduction. First, the flow balance valve + water flow switch In the water source heat pump outlet installed flow balance valve, flow meter to adjust the flow balance valve to the unit demand flow, the disadvantage of this method is the flow balance valve expensive, the other balance of the cost of flow test price Accounting for 30% of the balance valve costs, this fee is also higher. In addition, water flow switch must also be installed to provide water source heat pump unit controller feedback signal. If the system does not install the flow balance valve will be difficult to ensure the required flow of water units, the results prone to high pressure refrigeration system protection, the compressor may have failed, and if you do not install the water flow switch, the system operator may not be able to confirm the system has no water flow, Compressor may cause the boot run in the absence of water flow, but also easily lead to compressor failure. In addition, because the flow balance valve is based on differential pressure to adjust the flow, will have some resistance to the water system. Second, the pressure differential flow switch + ball valve This method is to use casing or plate heat exchanger inlet and outlet pressure drop and flow curve to complete the differential pressure switch has a clear action and reset the flow rate, the reset flow is Refers to the water flow through the heat exchanger water flow to make it close after the pump is running, the action flow refers to the flow down to the flow when the differential pressure switch is off, the reset flow can detect the flow of the water system meets the design requirements, the correct Set the pressure switch to reset the flow rate to ensure that the water flow through the heat exchanger is required, usually used in the water source heat pump water side (water side) of the pressure switch reset value flow rate greater than 80% of the rated flow, so you can basically guarantee that through the exchange The flow of the heater is appropriate. The actual application of pressure switch can be installed directly in the plant by the factory or installed in the field, before the installation must be tested for pressure and flow to get the appropriate pressure switch and reset the water flow settings, the specific use of By adjusting the opening of the ball valve so that the pressure switch can be closed, then the water flow through the heat exchanger has been greater than 80% of the rated flow. At the same time as a flow control switch with flow control accuracy, no additional resistance to the system, but also on the pipe diameter is not required and no interference of water flow disturbance characteristics, can replace any form of target flow switch as HVAC water system flow control . This method is a debugging simple, low cost, reliable control of water source heat pump water flow control solutions.
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