A large number of low-temperature air source variable frequency heat pump control system

Abstract

The utility model discloses a kind of big match number low-temperature air source variable frequency heat pump control systems, including variable frequency unit, fixed frequency unit and the control unit for controlling variable frequency unit and fixed frequency unit;The control unit includes centralized controller, remote communication module connected with centralized controller and local controller connected with centralized controller.The device can control the low-temperature air source heat pump system of big match number multiple fixed frequency and variable frequency compressor combination, when terminal load changes, the number and frequency of compressor can be adjusted by centralized control system, so that the heating / cooling capacity of unit and terminal consumption keep consistent, maintain the stability of water temperature, remote communication module can also be connected to upload data to server, view and control through remote mobile phone, computer.

Description

Technical Field

[0001] This utility model relates to heat source towers in the field of air conditioning technology, specifically a high-capacity low-temperature air source variable frequency heat pump control system. Background Technology

[0002] In the current technology, the application of low-temperature air source heat pump units is becoming more and more widespread. The existing low-temperature air source heat pump control system mostly adopts local control in the form of single-chip microcomputer. When multiple compressors are running in coordination, intelligent balanced operation is not achieved. As a result, when multiple compressors exist in a unit, only some units need to run for part of the load. Some compressors run for a long time, while others are shut down for a long time. The compressors in the unit do not receive even wear, which affects the service life of the whole unit.

[0003] Furthermore, current low-temperature air source heat pump units primarily use fixed-frequency scroll compressors. Under partial load, the loading and unloading of the compressor causes significant fluctuations in water temperature, affecting the heating or cooling experience. Operation is generally controlled by a local controller; moreover, the heat exchange efficiency of the shell-and-tube heat exchangers used in existing technology is not significant enough and needs improvement.

[0004] Therefore, in order to solve the above problems, it is necessary to develop a high-capacity low-temperature air source variable frequency heat pump control system with a reasonable structure and improved heat exchange efficiency. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a control system for a high-capacity, low-temperature air-source variable frequency heat pump; the technical solution is as follows: A high-capacity low-temperature air source variable frequency heat pump control system includes a variable frequency unit, a fixed frequency unit, and a control unit for controlling the variable frequency unit and the fixed frequency unit; the control unit includes a centralized controller, a remote communication module connected to the centralized controller, and a local controller connected to the centralized controller. The variable frequency unit includes a variable frequency scroll compressor, a variable frequency unit four-way valve, a variable frequency unit shell and tube heat exchanger, a variable frequency unit economizer, a variable frequency unit main expansion valve, and a variable frequency unit finned heat exchanger connected in sequence. The variable frequency unit finned heat exchanger is then returned to the variable frequency scroll compressor through the variable frequency unit four-way valve. The fixed-frequency unit includes a fixed-frequency scroll compressor, a fixed-frequency unit four-way valve, a fixed-frequency unit shell and tube heat exchanger, a fixed-frequency unit economizer, a fixed-frequency unit main expansion valve, and a fixed-frequency unit finned heat exchanger connected in sequence. The fixed-frequency unit finned heat exchanger is then returned to the fixed-frequency scroll compressor through the fixed-frequency unit four-way valve. The centralized controller controls the variable frequency scroll compressor, the four-way valve of the variable frequency unit, and the main expansion valve of the variable frequency unit in the variable frequency unit; The centralized controller also controls the fixed-frequency scroll compressor, the fixed-frequency four-way valve, and the fixed-frequency main circuit expansion valve in the fixed-frequency unit.

[0006] Furthermore, the frequency converter in the frequency converter unit is also equipped with a frequency converter unit auxiliary circuit, which is connected to the expansion valve of the main circuit of the frequency converter unit, and a frequency converter unit auxiliary circuit expansion valve is also installed on the frequency converter unit auxiliary circuit.

[0007] Furthermore, the fixed-frequency generator set's economizer is also equipped with a fixed-frequency generator set auxiliary circuit, which is connected to the main circuit expansion valve of the fixed-frequency generator set, and a fixed-frequency generator set auxiliary circuit expansion valve is also installed on the fixed-frequency generator set auxiliary circuit.

[0008] Furthermore, the fixed-frequency unit finned heat exchanger is equipped with a fixed-frequency fan; the variable-frequency unit finned heat exchanger is equipped with a variable-frequency fan.

[0009] Furthermore, the centralized controller controls the finned heat exchangers of the fixed-frequency unit and the variable-frequency unit by adjusting the fixed-frequency fan and the variable-frequency fan.

[0010] Furthermore, it also includes a unit inlet pipe and a unit outlet pipe; the unit inlet pipe and the unit outlet pipe respectively enter the shell-and-tube heat exchanger of the variable frequency unit and the shell-and-tube heat exchanger of the fixed frequency unit; and temperature sensors are installed on both the unit inlet pipe and the unit outlet pipe; and the centralized controller is connected to the temperature sensors.

[0011] Furthermore, the shell-and-tube heat exchanger of the variable frequency unit and the shell-and-tube heat exchanger of the fixed frequency unit have the same structure, including a shell, a flange installed on one side of the shell, an inlet pipe and an outlet pipe installed on the flange, and a U-shaped heat exchange tube installed inside the shell, with the two ends of the heat exchange tube connected to the inlet pipe and the outlet pipe respectively; the unit water inlet pipe is installed on the left side of the shell, and the unit water outlet pipe is installed on the right side.

[0012] Furthermore, the housing is also equipped with several vertical first heat exchange plates and second heat exchange plates. The first heat exchange plate is fixed to the inner wall of the housing, and an overflow hole is provided in the middle of the first heat exchange plate. The heat exchange tubes in the housing pass through the first heat exchange plate. The second heat exchange plate is fixed to the heat exchange tubes. An overflow gap is left between the edge of the second heat exchange plate and the inner wall of the housing. After the heat exchange tubes pass through the second heat exchange plate, the heat exchange tubes are fixed to the second heat exchange plate.

[0013] Furthermore, the first heat exchange plate and the second heat exchange plate are arranged alternately, and the spacing between adjacent heat exchange plates is the same.

[0014] Beneficial effects: This utility model has the following beneficial effects: 1) This device can control a low-temperature air source heat pump system consisting of multiple fixed-frequency and variable-frequency compressors of large capacity. When the terminal load changes, the number and frequency of the compressors can be adjusted through the centralized control system to keep the heating / cooling capacity of the unit consistent with the terminal consumption and maintain the stability of the water temperature. It can also be connected to a remote communication module to upload data to the server and be viewed and controlled remotely via mobile phone or computer. 2) This device can support the installation of heat exchange tubes through the first heat exchange plate. After all, the heat exchange tubes are suspended in the shell. The design of the heat exchange plate can fix the heat exchange tubes relatively stably, and the second heat exchange plate can also be fixed through the heat exchange tubes. The overall structure is stable and reliable.

[0015] 3) This device can increase the heat exchange area through heat exchange tubes. After the heat exchange tubes and heat exchange plates are installed in correspondence, the heat inside the heat exchange tubes is conducted to the heat exchange plates, and the heat exchange area with the water in the shell is significantly increased, effectively improving the heat exchange efficiency.

[0016] 3) After setting two different heat exchange plates, the water flow process is increased. The water needs to pass through the flow holes and then through the flow gaps, which increases the water flow time. The flow process must pass through the heat exchange tubes, which can also effectively increase the heat exchange efficiency and quality. Attached Figure Description

[0017] Figure 1 This is a structural diagram of the present utility model; Figure 2 This is a structural diagram of the shell-and-tube heat exchanger of this utility model; Figure 3 for Figure 2 AA view; Figure 4 for Figure 2 BB view. Detailed Implementation

[0018] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments. These embodiments are implemented under the premise of the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0019] like Figure 1 As shown, a high-capacity low-temperature air source variable frequency heat pump control system includes a variable frequency unit, a fixed frequency unit, and a control unit for controlling the variable frequency unit and the fixed frequency unit; the control unit includes a centralized controller, a remote communication module connected to the centralized controller, and a local controller connected to the centralized controller. The variable frequency unit includes a variable frequency scroll compressor 1, a variable frequency unit four-way valve 12, a variable frequency unit shell and tube heat exchanger 16, a variable frequency unit economizer 17, a variable frequency unit main expansion valve 14, and a variable frequency unit finned heat exchanger 18 connected in sequence. The variable frequency unit finned heat exchanger 18 is then returned to the variable frequency scroll compressor 1 through the variable frequency unit four-way valve 12. The fixed-frequency unit includes a fixed-frequency scroll compressor 8, a fixed-frequency unit four-way valve 9, a fixed-frequency unit shell and tube heat exchanger 19, a fixed-frequency unit economizer 20, a fixed-frequency unit main circuit expansion valve 5, and a fixed-frequency unit finned heat exchanger 21 connected in sequence. The fixed-frequency unit finned heat exchanger 21 is then returned to the fixed-frequency scroll compressor 8 through the fixed-frequency unit four-way valve 9. The centralized controller controls the variable frequency scroll compressor 1, the variable frequency unit four-way valve 12, and the variable frequency unit main circuit expansion valve 14 in the variable frequency unit; The centralized controller also controls the fixed-frequency scroll compressor 8, the fixed-frequency unit four-way valve 9, and the fixed-frequency unit main circuit expansion valve 5 in the fixed-frequency unit.

[0020] The frequency converter economizer 17 in the frequency converter unit is also equipped with a frequency converter auxiliary circuit, which is connected to the frequency converter main circuit expansion valve 14, and a frequency converter auxiliary circuit expansion valve 13 is also installed on the frequency converter auxiliary circuit.

[0021] The fixed-frequency generator set economizer 20 is also equipped with a fixed-frequency generator set auxiliary circuit, which is connected to the fixed-frequency generator set main circuit expansion valve 5, and a fixed-frequency generator set auxiliary circuit expansion valve 6 is also installed on the fixed-frequency generator set auxiliary circuit.

[0022] The fixed-frequency unit finned heat exchanger 21 is equipped with a fixed-frequency fan; the variable-frequency unit finned heat exchanger 18 is equipped with a variable-frequency fan 7.

[0023] The centralized controller controls the finned heat exchanger 21 of the fixed-frequency unit and the finned heat exchanger 18 of the variable-frequency unit by adjusting the fixed-frequency fan and the variable-frequency fan 7.

[0024] It also includes a unit inlet pipe 15 and a unit outlet pipe 10; the unit inlet pipe 15 and the unit outlet pipe 10 enter the variable frequency unit shell and tube heat exchanger 16 and the fixed frequency unit shell and tube heat exchanger 19 respectively; and temperature sensors are installed on the unit inlet pipe 15 and the unit outlet pipe 10; and the centralized controller is connected to the temperature sensors.

[0025] like Figure 2As shown, the shell-and-tube heat exchanger 16 of the variable frequency unit and the shell-and-tube heat exchanger 19 of the fixed frequency unit have the same structure, including a shell 22. A flange 23 is installed on one side of the shell 22, and an inlet pipe 24 and an outlet pipe 25 are installed on the flange 23. A U-shaped heat exchange tube 26 is installed inside the shell 22, and the two ends of the heat exchange tube 26 are connected to the inlet pipe 24 and the outlet pipe 25, respectively. The unit water inlet pipe 15 is installed on the left side of the shell 22, and the unit water outlet pipe 10 is installed on the right side.

[0026] like Figure 3 and Figure 4 As shown, several vertical first heat exchange plates 27 and second heat exchange plates 28 are also installed inside the shell 22. The first heat exchange plate 27 is fixed to the inner wall of the shell 22. An overflow hole 29 is provided at the middle position of the first heat exchange plate 27, and the heat exchange tube 26 inside the shell 22 passes through the first heat exchange plate 27. The second heat exchange plate 28 is fixed on the heat exchange tube 26. An overflow gap 30 is left between the edge of the second heat exchange plate 28 and the inner wall of the shell 22. After the heat exchange tube 26 passes through the second heat exchange plate 28, the heat exchange tube 26 is fixed on the second heat exchange plate 28.

[0027] The first heat exchange plate 27 and the second heat exchange plate 28 are arranged alternately, and the spacing between adjacent heat exchange plates is the same.

[0028] The specific working process of this device is as follows: The temperature is detected by the unit's inlet water temperature sensor. When the difference between the detected return water temperature and the set target temperature is large, in order to quickly raise the water temperature to the set value, the temperature signal detected by the unit's inlet water temperature sensor is transmitted to the unit's central controller. The central controller compares the received return water temperature value with the set required temperature value. If the difference exceeds a certain range, it sends start commands to the fixed-frequency component fan and the variable-frequency component fan. After a delay of several seconds, it sends start commands to the fixed-frequency scroll compressor and the variable-frequency scroll compressor, allowing the unit to start heating operation. Simultaneously, according to the set heating and cooling operating modes, it sends commands to the fixed-frequency component four-way valve and the variable-frequency component four-way valve to indicate whether the corresponding four-way valve needs to switch to heating or cooling. During the entire unit operation, it is also necessary to adjust the operating status of the fixed-frequency component main expansion valve, the fixed-frequency component auxiliary expansion valve, the variable-frequency component main expansion valve, and the variable-frequency component auxiliary expansion valve to ensure the unit operates in its optimal state.

[0029] When the unit detects that the temperatures detected by the return water temperature sensor and the outlet water temperature sensor are close to the set target temperature, the unit's central controller first sends a frequency reduction command to the variable frequency scroll compressor. This reduces the operating frequency of the variable frequency scroll compressor, thereby decreasing the unit's total heating capacity and slowing down the rate of temperature rise detected by the inlet water temperature sensor. During this operation, the water temperature detected by the inlet water temperature sensor is continuously compared with the set target temperature, thereby adjusting the operating frequency of the variable frequency scroll compressor to ensure that the actual water temperature detected by the inlet water temperature sensor is approximately close to the set target temperature.

[0030] If the variable frequency scroll compressor has already run at its lowest frequency, but the unit's heating capacity is still greater than the terminal load demand, causing the water temperature detected by the unit's inlet water temperature sensor to rise further to exceed the set target temperature, the unit will first stop the operation of the fixed frequency scroll compressor, send a stop command to the fixed frequency component fan, and at the same time quickly increase the operating frequency of the variable frequency scroll compressor to compensate for the drop in water temperature caused by the reduction in heating capacity due to the shutdown of the fixed frequency scroll compressor.

[0031] During continuous operation, the frequency of the variable frequency scroll compressor is controlled by the temperature detected by the unit's inlet water temperature sensor, so that the unit's heating capacity is close to the terminal load and the temperature detected by the unit's inlet water temperature sensor is consistent with the set target temperature.

[0032] During the water temperature drop, the frequency of the variable frequency scroll compressor is increased to maintain a stable water temperature. If the water temperature still cannot rise to the set target temperature after the variable frequency scroll compressor reaches its maximum frequency, the fixed frequency scroll compressor will be started, and the frequency of the variable frequency scroll compressor will be adjusted to maintain the water temperature.

[0033] The unit's heating, cooling, and defrosting operations are achieved by controlling the four-way valve of the fixed-frequency component and the four-way valve of the variable-frequency component.

[0034] The unit is controlled through the human-machine interface of the local controller, which allows switching between cooling and heating operation modes and adjusting the target temperature. The unit's operating data is sent to a remote server via a remote communication module, which can be viewed and controlled remotely via mobile phone or computer.

[0035] This device also provides a specific structure of a shell-and-tube heat exchanger. The shell-and-tube heat exchanger of this device mainly has two heat exchange plates with different structures inside the shell. First, the first heat exchange plate is fixed to the inner wall of the shell, and a flow hole is provided in the middle position. The second heat exchange plate is designed with a flow gap between the outer edge and the inner wall of the shell. The second heat exchange plate is directly fixed to the heat exchange tube.

[0036] With this setup, the heat exchange tubes can be supported by the first heat exchange plate, since the heat exchange tubes are suspended inside the shell. The heat exchange plate design can securely fix the heat exchange tubes, and the second heat exchange plate can also be fixed by the heat exchange tubes, making the overall structure stable and reliable.

[0037] On the other hand, the heat exchange area can be increased by using heat exchange tubes. After the heat exchange tubes and heat exchange plates are installed in correspondence, the heat inside the heat exchange tubes is conducted to the heat exchange plates, and the heat exchange area with the water in the shell is significantly increased, effectively improving the heat exchange efficiency.

[0038] Furthermore, by setting two different heat exchange plate intervals, the water flow process is increased. The water needs to pass through the flow holes and then through the flow gaps, which increases the water flow time. Since the flow process must pass through the heat exchange tubes, it can also effectively increase the heat exchange efficiency and quality.

[0039] The above-described specific embodiments are merely preferred embodiments of this utility model and are not intended to limit the implementation of this utility model or the scope of the claims. All equivalent changes and modifications made in accordance with the scope of protection of this utility model patent application should be included within the scope of this utility model patent application.

Claims

1. A control system for a high-capacity low-temperature air-source variable frequency heat pump, characterized in that: It includes variable frequency units, fixed frequency units, and control units for controlling the variable frequency units and fixed frequency units; the control unit includes a centralized controller, a remote communication module connected to the centralized controller, and a local controller connected to the centralized controller. The variable frequency unit includes a variable frequency scroll compressor (1), a variable frequency unit four-way valve (12), a variable frequency unit shell and tube heat exchanger (16), a variable frequency unit economizer (17), a variable frequency unit main expansion valve (14), and a variable frequency unit finned heat exchanger (18) connected in sequence. The variable frequency unit finned heat exchanger (18) is then returned to the variable frequency scroll compressor (1) through the variable frequency unit four-way valve (12). The fixed-frequency unit includes a fixed-frequency scroll compressor (8), a fixed-frequency unit four-way valve (9), a fixed-frequency unit shell and tube heat exchanger (19), a fixed-frequency unit economizer (20), a fixed-frequency unit main circuit expansion valve (5), and a fixed-frequency unit finned heat exchanger (21) connected in sequence. The fixed-frequency unit finned heat exchanger (21) is then returned to the fixed-frequency scroll compressor (8) through the fixed-frequency unit four-way valve (9). The centralized controller controls the variable frequency scroll compressor (1), the variable frequency unit four-way valve (12), and the variable frequency unit main circuit expansion valve (14) in the variable frequency unit. The centralized controller also controls the fixed-frequency scroll compressor (8), the fixed-frequency unit four-way valve (9), and the fixed-frequency unit main circuit expansion valve (5) in the fixed-frequency unit. It also includes a unit inlet pipe (15) and a unit outlet pipe (10); the unit inlet pipe (15) and the unit outlet pipe (10) respectively enter the variable frequency unit shell-and-tube heat exchanger (16) and the fixed frequency unit shell-and-tube heat exchanger (19); and temperature sensors are installed on the unit inlet pipe (15) and the unit outlet pipe (10); and the centralized controller is connected to the temperature sensors. The variable frequency unit shell-and-tube heat exchanger (16) and the fixed frequency unit shell-and-tube heat exchanger (19) have the same structure, including a shell (22). A flange (23) is installed on one side of the shell (22). An inlet pipe (24) and an outlet pipe (25) are installed on the flange (23). A U-shaped heat exchange tube (26) is installed inside the shell (22). The two ends of the heat exchange tube (26) are connected to the inlet pipe (24) and the outlet pipe (25) respectively. The unit water inlet pipe (15) is installed on the left side of the shell (22), and the unit water outlet pipe (10) is installed on the right side. The shell (22) is also equipped with several vertical first heat exchange plates (27) and second heat exchange plates (28). The first heat exchange plate (27) is fixed on the inner wall of the shell (22). An overflow hole (29) is provided at the middle position of the first heat exchange plate (27), and the heat exchange tube (26) in the shell (22) passes through the first heat exchange plate (27). The second heat exchange plate (28) is fixed on the heat exchange tube (26). An overflow gap (30) is left between the edge of the second heat exchange plate (28) and the inner wall of the shell (22). After the heat exchange tube (26) passes through the second heat exchange plate (28), the heat exchange tube (26) is fixed on the second heat exchange plate (28).

2. The control system for a large-capacity low-temperature air source variable frequency heat pump according to claim 1, characterized in that: The frequency converter economizer (17) in the frequency converter unit is also equipped with a frequency converter auxiliary circuit, which is connected to the frequency converter main circuit expansion valve (14), and a frequency converter auxiliary circuit expansion valve (13) is also installed on the frequency converter auxiliary circuit.

3. The control system for a large-capacity low-temperature air source variable frequency heat pump according to claim 1, characterized in that: The fixed-frequency generator set economizer (20) is also equipped with a fixed-frequency generator set auxiliary circuit. The fixed-frequency generator set auxiliary circuit is connected to the fixed-frequency generator set main circuit expansion valve (5), and a fixed-frequency generator set auxiliary circuit expansion valve (6) is also installed on the fixed-frequency generator set auxiliary circuit.

4. The control system for a large-capacity low-temperature air source variable frequency heat pump according to claim 1, characterized in that: The fixed-frequency unit finned heat exchanger (21) is equipped with a fixed-frequency fan; the variable-frequency unit finned heat exchanger (18) is equipped with a variable-frequency fan (7).

5. A high-capacity low-temperature air source variable frequency heat pump control system according to claim 4, characterized in that: The centralized controller controls the fixed-frequency unit finned heat exchanger (21) and the variable-frequency unit finned heat exchanger (18) by adjusting the fixed-frequency fan and the variable-frequency fan (7).

6. The control system for a large-capacity low-temperature air source variable frequency heat pump according to claim 1, characterized in that: The first heat exchange plate (27) and the second heat exchange plate (28) are arranged alternately, and the spacing between adjacent heat exchange plates is the same.

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