At present, in the field of refrigeration and air conditioning, large central air conditioning occasions widely used dry or full liquid screw cold water/Heat pump unit as the main refrigeration unit, the use of dry shell and tube type evaporator and screw compressor chiller called dry screw chiller; if used for water/ground source heat pump and other heating occasions, it is called screw ground source heat pump unit. If the unit uses a flooded evaporator, it is called a flooded screw chiller/heat pump unit. Compared with the all-liquid evaporator, the dry evaporator has lower cost, and the refrigeration unit with the dry evaporator has a simple structure and simple control, so it has been widely used. However, with the continuous improvement of social requirements for energy conservation and environmental protection, how to improve the energy efficiency ratio of the refrigeration host has become particularly important, and the heat exchange efficiency of the evaporator directly determines the energy efficiency ratio of the refrigeration host. However, due to the characteristics of the dry evaporator itself, the improvement of its heat transfer efficiency is limited, resulting in the dry screw chiller/heat pump unit can not be used in many occasions with high energy efficiency requirements. However, the oil return system and control of the full-liquid unit are more complex, and the refrigerant charge is much larger than that of the dry unit. Although the operating efficiency of all-hydraulic units is higher than that of traditional dry units, there are problems such as high failure rate, high cost, and large refrigerant charge.

ForOvercoming the shortcomings of existing technologies,Technical StaffA two-stage falling film screw ground source heat pump unit with high heat exchange efficiency, energy saving, safety and reliability, and stable operation is provided.The screw ground source heat pump unitThe following technical scheme is adopted: a two-stage falling film screw type ground source heat pump unit includes screw compressor, oil separator, condenser, oil cooler, two-stage falling film evaporator and economizer. The screw compressor is provided with economizer interface. The two-stage falling film evaporator includes evaporator shell, first liquid inlet, second liquid inlet, first distributor, second distributor, evaporator heat exchange tube, fluorine inlet and economizer. The outlet of the screw compressor is connected with the fluorine inlet of the oil separator through the exhaust pipeline, the economizer interface of the screw compressor is connected with the return port of the economizer through the return pipeline, the oil supply of the screw compressor is connected with the oil outlet of the oil cooler through the oil supply pipeline, the suction port of the screw compressor is connected with the fluorine outlet of the evaporator through the suction pipeline, and the oil return port of the oil separator is connected with the oil inlet of the oil cooler through the oil cooler, the fluorine outlet of the condenser is connected with the liquid inlet of the economizer through the liquid supply pipe of the economizer, and the oil return port of the evaporator is connected with the fluorine inlet of the oil separator through the gas return pipe.The screw ground source heat pump unitThe oil separator is arranged outside the condenser and includes a fluorine inlet and two fluorine outlets, the fluorine inlet is arranged in the middle of the oil separator, and the two fluorine outlets are respectively arranged on two sides of the oil separator; a separation screen is arranged in the passage between the fluorine inlet and the two fluorine outlets. A solenoid valve is also provided on the liquid supply pipeline between the economizer outlet and the evaporator fluorine inlet; a stop valve is provided on the return pipeline between the economizer interface of the screw-type ground source heat pump unit and the economizer return port; a solenoid valve and a manual valve are also provided on the liquid supply pipeline between the condenser fluorine outlet and the economizer inlet. A dry filter is provided on the liquid supply pipe between the fluorine outlet of the condenser and the liquid inlet of the economizer, and an oil filter is provided on the oil return pipe between the oil return port of the evaporator and the fluorine inlet of the oil separator, and between the oil return port of the oil separator and the oil inlet of the oil cooler.

Compared with the existing technology,The above screw type ground source heat pump unitHas the following beneficial effects:The screw ground source heat pump unitThe two-stage falling film evaporator is used to provide two liquid supply channels, which eliminates the technical problem of poor heat exchange efficiency at the lower part of the traditional one-stage falling film, and greatly improves the heat exchange efficiency of the evaporator;The screw ground source heat pump unitCan be used for central air conditioning refrigeration, water source heat pump heating and industrial refrigeration. High heat exchange efficiency, energy saving, safe and reliable, can replace traditional dry, full liquid and ordinary falling film screw cold water/heat pump unit, has a wide range of application value.