Industrial high-temperature heat pump systems

Abstract

The application discloses an industrial high-temperature heat pump system, which comprises a heat pump unit and a steam production unit. The heat pump unit is formed by a first compressor, a first condenser, a second compressor, a second condenser, a throttle valve and an evaporator which are sequentially connected to form a refrigerant circulation pipeline, and the second condenser is divided into a first section and a second section. The steam production unit is formed by a water tank and an ejector. A first-stage heating pipeline for heat exchange with the second section of the second condenser is arranged on the water tank, and a water pump and a three-way valve are arranged on the first-stage heating pipeline. A second-stage heating pipeline for heat exchange with the first section of the second condenser and the first condenser is connected to the three-way valve. The high-temperature steam inlet of the ejector is connected with the outlet of the second-stage heating pipeline, the flash steam inlet of the ejector is connected with the flash steam outlet of the water tank through a pipeline, and the high-temperature steam outlet of the ejector is provided with a pipeline leading to a target area. The application can improve the operation energy efficiency ratio of the heat pump system while ensuring the high-temperature heat pump heating temperature.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat pump, in particular to an industrial high-temperature heat pump system. BACKGROUND

[0002] In the industrial production process, such as textile, cigarette and paper, high-temperature steam is often used as a heat source to heat textiles, tobacco and paper. The traditional method is to use gas boilers to provide high-temperature steam. With the increasing awareness of environmental protection, the use of gas boilers is gradually decreasing. The newly emerging industrial high-temperature heat pump system uses the principle of reverse Carnot cycle to efficiently generate high-temperature steam to heat materials. The condensing temperature and pressure of the industrial high-temperature heat pump system directly determine the operating energy efficiency of the system. Industrial high-temperature heat pump systems that meet the use requirements often use a higher condensing temperature. Through research, it has been found that the energy efficiency ratio of the industrial high-temperature heat pump system gradually decreases as the condensing temperature increases. Therefore, under the premise of meeting the user's requirements, how to reduce the condensing pressure of the industrial high-temperature heat pump system and improve the energy efficiency of the heat pump system has become a problem to be solved. SUMMARY

[0003] In order to solve the above problems, the present application provides an industrial high-temperature heat pump system capable of maintaining a high energy efficiency ratio at a higher condensing temperature, which can specifically adopt the following technical scheme:

[0004] The industrial high-temperature heat pump system provided by the present application comprises

[0005] A heat pump unit comprising a first compressor, a first condenser, a second compressor, a second condenser, a throttling valve and an evaporator arranged in sequence, wherein the first compressor, the first condenser, the second compressor, the second condenser, the throttling valve and the evaporator are connected by pipelines to form a refrigerant circulation pipeline, and the second condenser is divided into a first section and a second section;

[0006] A steam generating unit comprising

[0007] A water tank, wherein a drain port, a return water port and a flash steam discharge port are arranged on the water tank, a first-stage heating pipeline for heat exchange with the second section of the second condenser is arranged between the drain port and the return water port, a water pump and a three-way valve are arranged on the first-stage heating pipeline, and a second-stage heating pipeline for heat exchange with the first section of the first condenser and the second condenser in sequence is connected to the three-way valve;

[0008] An ejector, wherein a high-temperature steam inlet, a flash steam inlet and a high-temperature steam outlet are arranged on the ejector, the high-temperature steam inlet is connected to the outlet of the second-stage heating pipeline, the flash steam inlet is connected to the flash steam discharge port of the water tank through a pipeline, and the high-temperature steam outlet is provided with a pipeline leading to a target area.

[0009] Furthermore, the refrigerant of the heat pump unit is R245fa, the first compressor and the second compressor are both twin-screw compressors, and the evaporator is an air-cooled fin heat exchanger or a shell and tube heat exchanger.

[0010] Preferably, the first section and the second section of the first condenser and the second condenser are both shell-and-tube heat exchangers.

[0011] In order to realize the automatic adjustment function and better adapt to the actual working conditions, the water pump is a variable frequency water pump, the three-way valve is an electric three-way valve, and the outlet of the secondary heating pipeline is provided with a pressure sensor. The signal output end of the pressure sensor is electrically connected to the signal input end of the PLC, and the control output end of the PLC is electrically connected to the control input end of the variable frequency water pump and the control input end of the electric three-way valve.

[0012] In order to achieve a better ejection effect, the high-temperature steam inlet and the high-temperature steam inlet of the ejector are coaxially arranged, and the flash steam inlet is arranged on the side of the ejector.

[0013] The industrial high-temperature heat pump system provided by the present invention has a simple structure, low cost, and is easy to maintain and repair. It is equipped with a first compressor, a second compressor, a first condenser, a second condenser, and an ejector. By controlling the cooling water flow in the first condenser, high-temperature steam of varying pressures is generated. The kinetic energy of the high-temperature steam and the ejector structure are used to reduce the pressure and cooling water temperature in the water tank connected to the second condenser, thereby reducing the condensing temperature and condensing pressure of the second condenser. This improves the operating energy efficiency of the heat pump system while ensuring the high-temperature heat pump heating temperature. Compared to existing electric heating or boiler heating systems, the present invention has lower energy consumption and can maintain high heating efficiency while meeting the heating demand. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0015] The following is a detailed description of an embodiment of the present invention in conjunction with the accompanying drawings. This embodiment is implemented based on the technical solution of the present invention, and a detailed implementation method and a specific construction process are given. However, the protection scope of the present invention is not limited to the following embodiment.

[0016] The industrial high-temperature heat pump system of the present invention, which consists of a heat pump unit and a steam generation unit, has a significant advantage over electric heating or boiler heating systems in that it has higher heating efficiency.

[0017] Specifically, if Figure 1As shown, the heat pump unit includes a first compressor 1, a first condenser 2, a second compressor 3, a second condenser (which is divided into a first section 41 and a second section 42), a throttle valve 5 and an evaporator 6, which are arranged in sequence. The first compressor 1, the first condenser 2, the second compressor 3, the second condenser, the throttle valve 5 and the evaporator 6 are connected by pipes to form a refrigerant circulation pipeline. The steam production unit includes a water tank 7 and an ejector 8, wherein the water tank 7 is provided with a drain port, a return port and a flash steam exhaust port. Between the drain port and the return port is a primary heating pipeline 91 for heat exchange with the second section 42 of the second condenser, and a water pump 92 and a three-way valve 93 are installed on the primary heating pipeline 91; the three-way valve 93 is connected to a secondary heating pipeline 94 for heat exchange with the first condenser 2 and the first section 41 of the second condenser in sequence; the ejector 8 is provided with a high-temperature steam inlet, a flash steam inlet and a high-temperature steam outlet, wherein the high-temperature steam inlet and the high-temperature steam inlet are coaxially arranged, and the flash steam inlet is located on the side of the ejector 8. The high-temperature steam inlet is connected to the outlet of the secondary heating pipeline 94, the flash steam inlet is connected to the flash exhaust port of the water tank 7 through a pipeline, and the high-temperature steam outlet is equipped with a pipeline leading to the target area.

[0018] The heat source for the high-temperature steam in ejector 8 is the first condenser 2 of the heat pump unit. This heat pump unit employs two-stage compression, directing the refrigerant from the outlet of the first compressor 1 into the first condenser 2, where it is cooled before being fed into the second condenser. This cooling process lowers the refrigerant vapor temperature at the inlet of the second compressor 3, reducing the compression work required and improving the heat pump unit's operating efficiency. To prevent damage to the second compressor 3 caused by refrigerant liquefaction due to the lower cooling temperature, the water inlet temperature to the first condenser 2 must be kept moderate.

[0019] The refrigerant at the outlet of the second compressor 3 enters the first section 41 of the second condenser, releasing sensible heat. At this point, the cooling water temperature in the first section 41 gradually rises, and the refrigerant vapor temperature decreases accordingly. By controlling the cooling water flow rate entering the first condenser 2, high-temperature steam at a specific pressure and temperature is obtained at the outlet of the secondary heating line 94.

[0020] After being cooled by the first section 41 of the second condenser, the refrigerant at the outlet of the second compressor 3 continues on to enter the second section 42 of the second condenser. There, the refrigerant releases heat, which is absorbed by the liquid water in the second section 42, which enters the water tank 7 through the primary heating line 91. The refrigerant then returns to the water tank 7 from the primary heating line 91 as liquid water at a higher temperature. Because the water temperature in the water tank 7 is relatively low, the condensing pressure in the second section 42 of the second condenser is relatively low, ensuring high energy efficiency for the heat pump unit.

[0021] The high-temperature steam generated by the heat exchange between the first condenser 2 and the first section 41 of the second condenser (located at the outlet of the secondary heating pipeline 94) enters the ejector 8, where it extracts the flash steam generated in the water tank 7. The high-temperature steam and flash steam are then mixed and supplied to the user through the high-temperature steam outlet and associated pipelines to meet various heating needs. The heating capacity of the steam is adjusted by the thermodynamic parameters of the high-temperature steam at the inlet of the ejector 8.

[0022] The ejector 8 can promptly draw out and remove flash gas generated in the water tank 7, thereby reducing the pressure within the water tank 7 and further lowering the temperature of the liquid water in the water tank 4. When the cooler cooling water in the water tank 7 enters the second section 42 of the second condenser via the water pump 92, heat exchange lowers the condensing temperature and pressure of the second condenser. This achieves the goal of lowering the condensing temperature and pressure of the high-temperature heat pump unit while providing a higher heating temperature.

[0023] Preferably, the refrigerant of the heat pump unit is R245fa, the first compressor 1 and the second compressor 3 are both twin-screw compressors, the evaporator 6 uses an air-cooled fin heat exchanger or a shell and tube heat exchanger according to the specific working conditions, and the first condenser 2 and the first section 41 and the second section 42 of the second condenser are both shell-and-tube heat exchangers, so as to obtain a good heating effect.

[0024] The water in the water tank 7 enters the second section 42 of the second condenser under the action of the water pump 92, and then passes through the three-way valve 93. Part of the water enters the first condenser 2 and the first section 41 of the second condenser, and the other part returns to the water tank 7. The opening degree of the three-way valve 93 is determined by the steam parameters at the outlet of the secondary heating pipeline 94.

[0025] To achieve automatic adjustment and better adapt to actual working conditions, a variable-frequency water pump is typically used for water pump 92, an electric three-way valve is used for three-way valve 93, and a pressure sensor 10 is installed at the outlet of secondary heating pipeline 94. The signal output of pressure sensor 10 is electrically connected to the signal input of the PLC, and the control output of the PLC is electrically connected to the control input of the variable-frequency water pump 92 and the control input of the electric three-way valve 93.

[0026] When the working conditions change or the user's demand changes, the steam parameters of the outlet section of the secondary heating pipeline 94 are collected and used to control the electric three-way valve 93 to control the cooling water flow entering the first condenser 2 and the first section 41 of the second condenser, thereby adjusting the high-pressure steam parameters and changing the inlet pressure and overall flow of the ejector 8 to adjust the heating temperature and heating capacity of the high-temperature heat pump system.

[0027] Through the above linkage relationship, the minimum cooling water flow rate for normal operation of the first condenser 2 and the second condenser, as well as the implementation of the cooling process and the safe operation of the high-temperature heat pump unit can be ensured.

[0028] It should be noted that, in the description of the present invention, terms indicating orientation or positional relationships such as “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “inside”, and “outside” are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

Claims

1. An industrial high-temperature heat pump system, characterized by: include A heat pump unit comprising a first compressor, a first condenser, a second compressor, a second condenser, a throttle valve, and an evaporator arranged in sequence, wherein the first compressor, the first condenser, the second compressor, the second condenser, the throttle valve, and the evaporator are connected by a pipeline to form a refrigerant circulation pipeline, wherein the second condenser is divided into a first section and a second section; Steam production unit, including a water tank, the water tank being provided with a drain port, a water return port, and a flash steam exhaust port; a primary heating pipeline for performing heat exchange with the second section of the second condenser being provided between the drain port and the water return port; a water pump and a three-way valve being provided on the primary heating pipeline; and a secondary heating pipeline for performing heat exchange with the first section of the first condenser and the first section of the second condenser being connected to the three-way valve; The ejector is provided with a high-temperature steam inlet, a flash steam inlet and a high-temperature steam outlet. The high-temperature steam inlet is connected to the outlet of the secondary heating pipeline, the flash steam inlet is connected to the flash exhaust port of the water tank through a pipe, and the high-temperature steam outlet is provided with a pipe leading to the target area.

2. The industrial high-temperature heat pump system according to claim 1, characterized in that: The refrigerant of the heat pump unit is R245fa, the first compressor and the second compressor are both twin-screw compressors, and the evaporator is an air-cooled fin heat exchanger or a shell and tube heat exchanger.

3. The industrial high-temperature heat pump system according to claim 1, characterized in that: The first section and the second section of the first condenser and the second condenser are both shell-and-tube heat exchangers.

4. The industrial high-temperature heat pump system according to claim 1, characterized in that: The water pump is a variable frequency water pump, the three-way valve is an electric three-way valve, and a pressure sensor is provided at the outlet of the secondary heating pipeline. The signal output end of the pressure sensor is electrically connected to the signal input end of the PLC, and the control output end of the PLC is electrically connected to the control input end of the variable frequency water pump and the control input end of the electric three-way valve.

5. The industrial high-temperature heat pump system according to claim 1, characterized in that: The high-temperature steam inlet and the high-temperature steam inlet of the ejector are coaxially arranged, and the flash steam inlet is arranged on the side of the ejector.

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