Hot water preparation skid-mounted system and control method thereof

Abstract

The invention discloses a hot water preparation skid-mounted system and a control method thereof. The system comprises a gas generator set, an air source heat pump and an electric cabinet. The electric control box comprises a main circuit breaker, a programmable logic controller, a compensation capacitor and a contactor; the contactor comprises a capacitor switching contactor and a contactor coil; the contactor coil is connected with the main circuit breaker, the gas generator set is connected with the main circuit breaker, the air source heat pump is connected with the main circuit breaker, the main circuit breaker is connected with the compensation capacitor through the capacitor switching contactor, and the programmable logic controller is connected with the contactor coil, the gas generator set and the air source heat pump. By arranging the compensation capacitor, the operation power can be supplemented to reach the rated power when the power of the gas generator set and the air source heat pump is insufficient during island mode operation without grid-connected conditions, so that the overall energy efficiency ratio reaches the rated value, and the economic benefit is improved.

Description

Technical Field

[0001] The present application relates to the technical field of gas power generation and hot water preparation, and in particular to a hot water preparation skid-mounted system and a control method thereof. Background Art

[0002] The cogeneration system consisting of a gas generator and an air source heat pump uses clean energy as fuel, can produce hot water efficiently, and has the advantages of low noise, low harmful gas emissions, and flexible usage. It can be widely used in apartments, hotels, schools, hospitals, drying rooms, electroplating workshops and other scenarios.

[0003] Air source heat pumps are classified as inductive loads (the main component is the compressor) in terms of load type. When they are working normally, they not only need to obtain active power from the power supply side to ensure the operation of components such as the compressor, but also need to obtain a large amount of reactive power from the power supply side to establish and maintain the magnetic field. The active power provided by the gas generator set is greater than the rated operating power of the air source heat pump, but the reactive power provided by the gas generator set is less than the reactive power required for the normal operation of the air source heat pump. In the grid-connected operation mode of the gas generator, the reactive power required by the air source heat pump can be provided by the large power grid, but when the gas generator set is operated in an island mode without grid-connected conditions, the reactive power demand of the air source heat pump cannot be met, the operating power of the air source heat pump will be less than the rated power, the overall energy efficiency ratio will be lower than the rated value, and the economic benefits will be poor. Summary of the invention

[0004] The embodiment of the present application provides a hot water preparation skid-mounted system and a control method thereof, which can improve the operating efficiency of the air source heat pump in the island mode, and solve the technical problem that when the gas generator set is operated in the island mode without the conditions for grid connection, the reactive power demand of the air source heat pump cannot be met, the operating power of the air source heat pump will be less than the rated power, the overall energy efficiency ratio is lower than the rated value, and the economic benefits are poor.

[0005] The embodiment of the present application provides a skid-mounted system for preparing hot water, including a gas generator set, an air source heat pump and an electric control box;

[0006] The electric control box includes a main circuit breaker, a programmable logic controller, a compensation capacitor and a contactor, and the contactor includes a capacitor switching contactor and a contactor coil;

[0007] The gas generator set is connected to the main circuit breaker, the air source heat pump is connected to the main circuit breaker, the main circuit breaker is connected to the compensation capacitor through the capacitor switching contactor, and the programmable logic controller is connected to the contactor coil, the gas generator set and the air source heat pump;

[0008] When the hot water preparation skid-mounted system is started, the programmable logic controller sends a start-up instruction to the gas-fired generator set. After a first delay, the programmable logic controller sends a start-up instruction to the air source heat pump. When the programmable logic controller monitors that the power factor of the gas-fired generator set is greater than or equal to a first threshold value, it determines that the operating power of the air source heat pump has not reached the rated value, and keeps the air source heat pump running. When the programmable logic controller monitors that the power factor of the gas-fired generator set is less than the first threshold value, it determines that the operating power of the air source heat pump has reached the rated value, the programmable logic controller controls the contactor to close, the compensation capacitor is put into use and keeps the air source heat pump running.

[0009] Furthermore, the programmable logic controller is connected to the gas generator set via a digital control signal line, and the electrical control box is used to control the start, stop, reset and emergency stop of the gas generator set; the programmable logic controller is connected to the air source heat pump via a digital control signal line, and the electrical control box is used to control the start, stop, emergency stop and reset of the air source heat pump.

[0010] Furthermore, the programmable logic controller is connected to the gas generator set via a 485 signal line, and the electrical control box is used to obtain operating data of the gas generator set, and the operating data includes voltage, frequency, current and power factor; the programmable logic controller is connected to the air source heat pump via a 485 signal line, and the electrical control box is used to remotely control the start and stop of the air source heat pump and set the operating mode and operating parameters of the air source heat pump.

[0011] Furthermore, the gas-fired generator set includes at least one gas-fired generator, and the gas-fired generator is connected to the main circuit breaker via a power cable.

[0012] Furthermore, the air source heat pump includes at least one compressor, and the compressor is connected to the main circuit breaker via a power cable.

[0013] Furthermore, the capacitance compensation amount of the compensation capacitor is calculated according to the formula Calculate, where Q C is the capacity to be compensated, in kvar; P C is the rated active power of the air source heat pump, in kW; To compensate for the sine value of the power factor angle of the front gas generator set; It is the sine value of the power factor angle of the gas generator set after compensation.

[0014] Furthermore, the hot water preparation skid-mounted system further comprises a base; the gas generator set, the air source heat pump and the electric control box can be detachably mounted on the base; the gas generator set and the air source heat pump are arranged on both sides of the electric control box;

[0015] When the hot water preparation skid-mounted system is shut down, the programmable logic controller sends a shutdown command to the air source heat pump, and the air source heat pump starts to reduce power and shut down; when the programmable logic controller monitors that the power factor of the gas generator set is less than or equal to a second threshold, it determines that the operating power of the air source heat pump is in the process of decreasing, and keeps the air source heat pump from reducing power; when the programmable logic controller monitors that the power factor of the gas generator set is greater than the second threshold, the programmable logic controller controls the contactor to open, cuts off the compensation capacitor and keeps the air source heat pump from reducing power until the air source heat pump shuts down; the programmable logic controller sends a shutdown command to the gas generator set to control the gas generator set to shut down.

[0016] The present application also provides a control method for the above-mentioned hot water preparation skid-mounted system, which comprises:

[0017] The electric control box detects the power demand in real time;

[0018] When the electric control box obtains the electricity demand, it controls the hot water preparation skid-mounted system to start;

[0019] When the hot water preparation skid-mounted system is started, the programmable logic controller sends a start instruction to the gas generator set, and after a first delay, the programmable logic controller sends a start instruction to the air source heat pump;

[0020] The programmable logic controller monitors the power factor of the gas generator set in real time. When the programmable logic controller monitors that the power factor of the gas generator set is greater than or equal to a first threshold, it determines that the operating power of the air source heat pump has not reached the rated value, and keeps the air source heat pump running; when the programmable logic controller monitors that the power factor of the gas generator set is less than the first threshold, it determines that the operating power of the air source heat pump has reached the rated value, the programmable logic controller controls the contactor to close, the compensation capacitor is put into use and keeps the air source heat pump running.

[0021] Furthermore, after the contactor is closed and the compensation capacitor is put into use, the method further includes:

[0022] When the programmable logic controller monitors that the power factor of the gas generator set is greater than or equal to a third threshold, the programmable logic controller controls the contactor to open and cut off the compensation capacitor.

[0023] Furthermore, the control method of the hot water preparation skid-mounted system also includes:

[0024] When the electric control box detects that there is no electricity demand, it controls the hot water preparation skid-mounted system to shut down;

[0025] When the hot water preparation skid-mounted system is shut down, the programmable logic controller sends a shutdown instruction to the air source heat pump, and the air source heat pump starts to reduce power and shut down;

[0026] The programmable logic controller monitors the power factor of the gas generator set in real time. When the programmable logic controller monitors that the power factor of the gas generator set is less than or equal to a second threshold, it determines that the operating power of the air source heat pump is in the process of decreasing, and keeps the air source heat pump to continue to reduce power; when the programmable logic controller monitors that the power factor of the gas generator set is greater than the second threshold, the programmable logic controller controls the contactor to open, cuts off the compensation capacitor and keeps the air source heat pump to continue to reduce power until the air source heat pump stops;

[0027] The programmable logic controller sends a shutdown instruction to the gas generator set to control the gas generator set to shut down.

[0028] The hot water preparation skid-mounted system and control method thereof provided in the embodiments of the present application can realize that when operating in an island mode without grid connection conditions, the operating power can be supplemented to the rated power when the power of the gas generator set and the air source heat pump is insufficient, thereby improving the power value of the hot water preparation skid-mounted system when operating in the island mode, so that the overall energy efficiency ratio reaches the rated value, and the economic benefits are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0030] Figure 1 A schematic diagram of the structure of a skid-mounted system for preparing hot water provided in an embodiment of the present application.

[0031] Figure 2 This is a circuit schematic diagram of the hot water preparation skid-mounted system provided in an embodiment of the present application.

[0032] Figure 3 A power supply and control circuit diagram of the hot water preparation skid-mounted system provided in an embodiment of the present application.

[0033] Figure 4 This is a startup flow chart of the hot water preparation skid-mounted system provided in an embodiment of the present application.

[0034] Figure 5 This is a shutdown flow chart of the hot water preparation skid-mounted system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0036] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0037] For details, please refer to Figure 1 , Figure 2 , Figure 3 An embodiment of the present application provides a hot water preparation skid-mounted system, which includes a gas generator set 1, an air source heat pump 2 and an electric control box 3.

[0038] The electric control box 3 includes a main circuit breaker 31 , a programmable logic controller 32 (PLC), a compensation capacitor 33 and a contactor 34 . The contactor 34 includes a capacitor switching contactor 341 and a contactor coil 342 .

[0039] The gas generator set 1 is connected to the main circuit breaker 31, the air source heat pump 2 is connected to the main circuit breaker 31, the main circuit breaker 31 is connected to the compensation capacitor 33 through the capacitor switching contactor 341, and the programmable logic controller 32 is connected to the contactor coil 342, the gas generator set 1 and the air source heat pump 2.

[0040] like Figure 4As shown, when the hot water preparation skid-mounted system is started, the programmable logic controller 32 sends a start instruction to the gas generator set 1. After a first delay, the programmable logic controller 32 sends a start instruction to the air source heat pump 2; when the programmable logic controller 32 monitors that the power factor of the gas generator set 1 is greater than or equal to a first threshold value, it is determined that the operating power of the air source heat pump 2 has not reached the rated value, and the air source heat pump 2 is kept running; when the programmable logic controller 32 monitors that the power factor of the gas generator set 1 is less than the first threshold value, it is determined that the operating power of the air source heat pump 2 has reached the rated value, the programmable logic controller 32 controls the contactor 34 to close, and the compensation capacitor 33 is put into use and keeps the air source heat pump 2 running.

[0041] The gas generator set 1 uses natural gas or other combustible gases with equivalent calorific value as fuel and outputs electrical energy to the outside; through the start, stop and other timing control of the electrical control box 3, the air source heat pump 2 obtains the electrical energy output by the gas generator set 1 and operates under rated conditions to achieve the purpose of hot water preparation.

[0042] In the island mode, since the air source heat pump 2 needs to obtain both active and reactive power when it is running at rated value, and the reactive power supply capacity of the gas generator set 1 is insufficient, the hot water preparation skid system needs to achieve high-efficiency operation by connecting a suitable compensation capacitor 33 in parallel. The specific implementation method is that when the air source heat pump 2 is started, if the power factor of the generator set decreases, the compensation capacitor 33 is connected in parallel to the power supply circuit of the air source heat pump 2 to increase the reactive power of the system so that the air source heat pump 2 can operate in the rated range; when the air source heat pump 2 is shut down, the active power gradually decreases. Due to the existence of the parallel compensation capacitor 33, the power factor of the generator set will increase. When the power factor reaches a certain value, the parallel compensation capacitor 33 needs to be cut off from the circuit, otherwise the circuit voltage continues to increase, which may cause overvoltage shock to the air source heat pump 2.

[0043] Hot water preparation skid mounted system circuit diagram Figure 2 shown.

[0044] Furthermore, the programmable logic controller 32 is connected to the gas generator set 1 via a digital control signal line, and the electrical control box 3 is used to control the start, stop, reset and emergency stop of the gas generator set 1; the programmable logic controller 32 is connected to the air source heat pump 2 via a digital control signal line, and the electrical control box 3 is used to control the start, stop, emergency stop and reset of the air source heat pump 2.

[0045] Furthermore, the programmable logic controller 32 is connected to the gas generator set 1 via a 485 signal line, and the electrical control box 3 is used to obtain the operating data of the gas generator set 1, and the operating data includes voltage, frequency, current and power factor; the programmable logic controller 32 is connected to the air source heat pump 2 via a 485 signal line, and the electrical control box 3 is used to remotely control the start and stop of the air source heat pump 2 and set the operating mode and operating parameters of the air source heat pump 2.

[0046] Furthermore, the gas generator set 1 includes at least one gas generator, and the gas generator is connected to the main circuit breaker 31 through a power cable.

[0047] Furthermore, the air source heat pump 2 includes at least one compressor, and the compressor is connected to the main circuit breaker 31 via a power cable.

[0048] The power supply and control circuit of the hot water preparation skid system in island mode. The strong current part of the hot water preparation skid system is the power part from the gas generator set 1 to the air source heat pump 2 through the electric control box 3. The weak current part of the hot water preparation skid system is the control circuit and communication circuit between the gas generator set 1 and the electric control box 3, and between the air source heat pump 2 and the electric control box 3. The power supply and control circuit of the hot water preparation skid system, such as Figure 3 As shown. The digital control signal between the gas generator set 1 and the electric control box 3 is used by the electric control box 3 to control the start, stop, reset, emergency stop, etc. of the gas generator set 1; the communication signal between the gas generator set 1 and the electric control box 3 adopts the commonly used 485 signal, and the main function is for the electric control box 3 to obtain the operating data of the gas generator set 1, such as voltage, frequency, current, power factor, etc. The digital control signal between the air source heat pump 2 and the electric control box 3 is used by the electric control box 3 to control the emergency stop and reset of the air source heat pump 2; the communication signal between the air source heat pump 2 and the electric control box 3 also adopts the 485 signal, and the main function is for the electric control box 3 to remotely control the start and stop of the air source heat pump 2 and set the operating mode and operating parameters of the air source heat pump 2. In the power circuit part, the power cable at the output end of the gas generator set 1 enters the electric control box 3 and is divided into two paths. One path directly enters the incoming line end of the air source heat pump 2, and the second path is connected in parallel with the first path, which is composed of a contactor 34 and a group of compensation capacitors 33.

[0049] The working principle of the hot water preparation skid-mounted system in island mode is mainly divided into three parts. The first part is the selection of compensation capacitor 33; the second part is the startup process of the hot water preparation skid-mounted system; and the third part is the shutdown process of the hot water preparation skid-mounted system.

[0050] The first part is the selection of the compensation capacitor 33. The capacity of the compensation capacitor 33 is very important. If the capacitor capacity is too large, it will cause risks such as overvoltage, harmonics, and system instability. If the capacitor capacity is too small, the reactive power compensation will be insufficient, the efficiency of the air source heat pump 2 will decrease, and it may also cause current fluctuations and affect the service life of the device.

[0051] Furthermore, the capacitance compensation amount of the compensation capacitor 33 is calculated according to the formula Calculate, where Q C is the capacity to be compensated, in kvar; P C is the rated active power of the air source heat pump 2, in kW; To compensate for the sine value of the power factor angle of the front gas generator set 1; It is the sine value of the power factor angle of gas generator set 1 after compensation.

[0052] In the actual selection process, it is necessary to determine it based on the actual operating parameters of the air source heat pump 2 and the gas generator set 1.

[0053] Furthermore, the hot water preparation skid-mounted system also includes a base 4; the gas generator set 1, the air source heat pump 2 and the electric control box 3 can all be detachably installed on the base 4; the gas generator set 1 and the air source heat pump 2 are arranged on both sides of the electric control box 3.

[0054] The second part is the startup process of the hot water preparation skid-mounted system. Figure 4As shown. The startup process of the hot water preparation skid-mounted system is to start the gas generator set 1 first, and then start the air source heat pump 2. After the system receives the startup command, the programmable logic controller 32 (PLC) in the electric control box 3 sends a remote startup signal to the gas generator set 1. After the gas generator set 1 starts for the first time of 1 minute, the PLC determines that the gas generator set 1 has been stably started according to the feedback signal of the gas generator set 1, and then sends a startup command to the air source heat pump 2 and starts to monitor the power factor of the gas generator set 1. When the power factor of the gas generator set 1 monitored by the PLC is ≥ the first threshold PF1, it means that the operating power of the air source heat pump 2 has not reached the rated value and is still in the process of increasing. At this time, the PLC does not intervene in the control. When the PLC monitors that the power factor of the gas generator set 1 is < the first threshold PF1, it means that the operating power of the air source heat pump 2 is close to the rated value at this time, and the reactive power provided by the generator set is insufficient. The PLC controls the capacitor switching contactor 341 to close through the digital output point, thereby putting the compensation capacitor 33 into parallel with the air source heat pump 2. After the compensation capacitor 33 is put into the system, the air source heat pump 2 can reach the rated operating power. The power factor value PF1 for judging the capacitor input condition should be determined based on the actual operation of the gas generator set 1 and the air source heat pump 2, combined with the monitoring values ​​such as the loop voltage and current, and refer to the power supply requirements of the air source heat pump 2 (such as the minimum power supply voltage, etc.).

[0055] The third part is the shutdown process of the hot water preparation skid-mounted system. Figure 5As shown. The shutdown process of the hot water preparation skid-mounted system is to stop the air source heat pump 2 first and then stop the gas generator set 1. After receiving the shutdown signal, the PLC sends a stop command to the air source heat pump 2, and the air source heat pump 2 starts to reduce power and shut down according to the logic and timing set by the unit itself. The PLC starts to monitor the power factor of the gas generator set 1. When the power factor is not greater than the second threshold PF2, it means that the power of the air source heat pump 2 is still in the process of decreasing and has not reached a smaller value; when the power factor exceeds the second threshold PF2, it means that the power of the air source heat pump 2 has dropped to a smaller value. At this time, due to the presence of the compensation capacitor 33 in the circuit, the voltage begins to rise. The PLC controls the capacitor switching contactor 341 to open the gate through the digital output, and removes the compensation capacitor 33 from the circuit. The air source heat pump 2 continues to reduce power until the shutdown process is completed. After reading the shutdown signal of the air source heat pump 2, the PLC sends a shutdown command to the gas generator set 1, and the gas generator set 1 gradually completes the shutdown process according to its own logic. After the gas generator set 1 is shut down, the system shuts down. Among them, the power factor value PF1 for judging the capacitor removal condition should also be comprehensively judged based on the actual operation conditions of the gas generator set 1 and the air source heat pump 2, combined with monitoring values ​​such as loop voltage and current, and refer to the required range of the air source heat pump 2 for the power supply (such as the maximum power supply voltage, etc.).

[0056] Specifically, Figure 5 As shown, when the hot water preparation skid-mounted system is shut down, the programmable logic controller 32 sends a shutdown command to the air source heat pump 2, and the air source heat pump 2 starts to reduce power and shut down; when the programmable logic controller 32 monitors that the power factor of the gas generator set 1 is less than or equal to the second threshold, it determines that the operating power of the air source heat pump 2 is in the process of decreasing, and keeps the air source heat pump 2 to continue to reduce power; when the programmable logic controller 32 monitors that the power factor of the gas generator set 1 is greater than the second threshold, the programmable logic controller 32 controls the contactor 34 to open, cuts off the compensation capacitor 33 and keeps the air source heat pump 2 to continue to reduce power until the air source heat pump 2 shuts down; the programmable logic controller 32 sends a shutdown command to the gas generator set 1 to control the gas generator set 1 to shut down.

[0057] The present application monitors the circuit operating parameters through the programmable logic controller 32 and reasonably controls the switching of the compensation capacitor 33, so that the air source heat pump 2 can operate under rated conditions, thereby improving the efficiency of the entire hot water preparation skid-mounted system.

[0058] The present application also provides a control method for the above-mentioned hot water preparation skid-mounted system, which comprises:

[0059] The electric control box 3 detects the power demand in real time;

[0060] When the electric control box 3 obtains the electricity demand, it controls the hot water preparation skid-mounted system to start;

[0061] When the hot water preparation skid-mounted system is started, the programmable logic controller 32 sends a start instruction to the gas generator set 1. After a first delay, the programmable logic controller 32 sends a start instruction to the air source heat pump 2.

[0062] The programmable logic controller 32 monitors the power factor of the gas generator set 1 in real time. When the programmable logic controller 32 monitors that the power factor of the gas generator set 1 is greater than or equal to a first threshold value, it determines that the operating power of the air source heat pump 2 has not reached the rated value, and keeps the air source heat pump 2 running; when the programmable logic controller 32 monitors that the power factor of the gas generator set 1 is less than the first threshold value, it determines that the operating power of the air source heat pump 2 has reached the rated value, the programmable logic controller 32 controls the contactor 34 to close, the compensation capacitor 33 is put into use and keeps the air source heat pump 2 running.

[0063] Furthermore, after the contactor 34 is closed and the compensation capacitor 33 is put into use, the method further includes:

[0064] When the programmable logic controller 32 monitors that the power factor of the gas generator set 1 is greater than or equal to a third threshold, the programmable logic controller 32 controls the contactor 34 to open, and removes the compensation capacitor 33 .

[0065] Furthermore, the control method of the hot water preparation skid-mounted system also includes:

[0066] When the electric control box 3 detects that there is no electricity demand, it controls the hot water preparation skid-mounted system to shut down;

[0067] When the hot water preparation skid-mounted system is shut down, the programmable logic controller 32 sends a shutdown instruction to the air source heat pump 2, and the air source heat pump 2 starts to reduce power and shut down;

[0068] The programmable logic controller 32 monitors the power factor of the gas generator set 1 in real time. When the programmable logic controller 32 monitors that the power factor of the gas generator set 1 is less than or equal to a second threshold value, it determines that the operating power of the air source heat pump 2 is in the process of decreasing, and keeps the air source heat pump 2 to continue to reduce power; when the programmable logic controller 32 monitors that the power factor of the gas generator set 1 is greater than the second threshold value, the programmable logic controller 32 controls the contactor 34 to open, cuts off the compensation capacitor 33 and keeps the air source heat pump 2 to continue to reduce power until the air source heat pump 2 stops;

[0069] The programmable logic controller 32 sends a shutdown instruction to the gas generator set 1 to control the gas generator set 1 to shut down.

[0070] The hot water preparation skid-mounted system and control method thereof provided in the embodiment of the present application can realize that when operating in an island mode without grid connection conditions, the compensation capacitor 33 is set, and the operating power can be supplemented to the rated power when the power of the gas generator set 1 and the air source heat pump 2 is insufficient, thereby improving the power value of the hot water preparation skid-mounted system when operating in the island mode, so that the overall energy efficiency ratio reaches the rated value, and the economic benefits are improved.

[0071] The existing hot water preparation system can reach the rated operating power when the generator set is connected to the grid. However, in an environment where the conditions for grid connection are not met, the generator set cannot provide sufficient reactive power, and the operating power of the air source heat pump will be lower than the rated value. In addition to the low operating efficiency and poor economy of the system, it may cause failures of equipment, lines, etc.

[0072] The automatic capacitor switching technology used in this application can solve the problem of the hot water preparation system operating in island mode. By switching the capacitor, the air source heat pump can operate at the rated working condition, thereby ensuring the high efficiency of the hot water preparation system and maximizing its economic benefits. This technology starts and stops with one button throughout the process, and the system is automatically controlled without human intervention, saving time and effort, and being economical and reliable.

[0073] The above is a detailed introduction to a hot water preparation skid-mounted system and a control method thereof provided in an embodiment of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solution to deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A hot water preparation skid-mounted system, characterized in that: include: Gas generator set, air source heat pump and electric control box; The electric control box includes a main circuit breaker, a programmable logic controller, a compensation capacitor and a contactor, and the contactor includes a capacitor switching contactor and a contactor coil; The gas generator set is connected to the main circuit breaker, the air source heat pump is connected to the main circuit breaker, the main circuit breaker is connected to the compensation capacitor through the capacitor switching contactor, and the programmable logic controller is connected to the contactor coil, the gas generator set and the air source heat pump; When the hot water preparation skid-mounted system is started, the programmable logic controller sends a start-up instruction to the gas-fired generator set. After a first delay, the programmable logic controller sends a start-up instruction to the air source heat pump. When the programmable logic controller monitors that the power factor of the gas-fired generator set is greater than or equal to a first threshold value, it determines that the operating power of the air source heat pump has not reached the rated value, and keeps the air source heat pump running. When the programmable logic controller monitors that the power factor of the gas-fired generator set is less than the first threshold value, it determines that the operating power of the air source heat pump has reached the rated value, the programmable logic controller controls the contactor to close, the compensation capacitor is put into use and keeps the air source heat pump running.

2. The hot water preparation skid-mounted system according to claim 1, characterized in that: The programmable logic controller is connected to the gas generator set via a digital control signal line, and the electrical control box is used to control the start, stop, reset and emergency stop of the gas generator set; the programmable logic controller is connected to the air source heat pump via a digital control signal line, and the electrical control box is used to control the start, stop, emergency stop and reset of the air source heat pump.

3. The hot water preparation skid-mounted system according to claim 1, characterized in that: The programmable logic controller is connected to the gas generator set via a 485 signal line, and the electrical control box is used to obtain the operating data of the gas generator set, and the operating data includes voltage, frequency, current and power factor; the programmable logic controller is connected to the air source heat pump via a 485 signal line, and the electrical control box is used to remotely control the start and stop of the air source heat pump and set the operating mode and operating parameters of the air source heat pump.

4. The hot water preparation skid-mounted system according to claim 1, characterized in that: The gas generator set includes at least one gas generator, and the gas generator is connected to the main circuit breaker through a power cable.

5. The hot water preparation skid-mounted system according to claim 1, characterized in that: The air source heat pump includes at least one compressor, which is connected to the main circuit breaker via a power cable.

6. The hot water preparation skid-mounted system according to claim 1, characterized in that: The capacitance compensation amount of the compensation capacitor is calculated according to the formula Calculate, where Q C is the capacity to be compensated, in kvar; P C is the rated active power of the air source heat pump, in kW; To compensate for the sine value of the power factor angle of the front gas generator set; It is the sine value of the power factor angle of the gas generator set after compensation.

7. The hot water preparation skid-mounted system according to claim 1, characterized in that: It also includes a base; the gas generator set, the air source heat pump and the electric control box can be detachably mounted on the base; the gas generator set and the air source heat pump are arranged on both sides of the electric control box; When the hot water preparation skid-mounted system is shut down, the programmable logic controller sends a shutdown command to the air source heat pump, and the air source heat pump starts to reduce power and shut down; when the programmable logic controller monitors that the power factor of the gas generator set is less than or equal to the second threshold, it is determined that the operating power of the air source heat pump is in the process of decreasing, and the air source heat pump is kept to continue to reduce power; When the programmable logic controller monitors that the power factor of the gas generator set is greater than a second threshold, the programmable logic controller controls the contactor to open, cuts off the compensation capacitor and keeps the air source heat pump from continuing to reduce power until the air source heat pump shuts down; the programmable logic controller sends a shutdown command to the gas generator set to control the gas generator set to shut down.

8. A control method for a hot water preparation skid-mounted system according to any one of claims 1 to 7, characterized in that: include: The electric control box detects the power demand in real time; When the electric control box obtains the electricity demand, it controls the hot water preparation skid-mounted system to start; When the hot water preparation skid-mounted system is started, the programmable logic controller sends a start instruction to the gas generator set, and after a first delay, the programmable logic controller sends a start instruction to the air source heat pump; The programmable logic controller monitors the power factor of the gas generator set in real time. When the programmable logic controller monitors that the power factor of the gas generator set is greater than or equal to a first threshold, it determines that the operating power of the air source heat pump has not reached the rated value, and keeps the air source heat pump running; when the programmable logic controller monitors that the power factor of the gas generator set is less than the first threshold, it determines that the operating power of the air source heat pump has reached the rated value, the programmable logic controller controls the contactor to close, the compensation capacitor is put into use and keeps the air source heat pump running.

9. The control method of the hot water preparation skid-mounted system according to claim 8, characterized in that: After the contactor is closed and the compensation capacitor is put into use, the method further includes: When the programmable logic controller monitors that the power factor of the gas generator set is greater than or equal to a third threshold, the programmable logic controller controls the contactor to open and cut off the compensation capacitor.

10. The control method of the hot water preparation skid-mounted system according to claim 8, characterized in that: Also includes: When the electric control box detects that there is no electricity demand, it controls the hot water preparation skid-mounted system to shut down; When the hot water preparation skid-mounted system is shut down, the programmable logic controller sends a shutdown instruction to the air source heat pump, and the air source heat pump starts to reduce power and shut down; The programmable logic controller monitors the power factor of the gas generator set in real time. When the programmable logic controller monitors that the power factor of the gas generator set is less than or equal to a second threshold, it is determined that the operating power of the air source heat pump is in a decreasing process, and the air source heat pump is kept to continue to reduce power; When the programmable logic controller monitors that the power factor of the gas generator set is greater than a second threshold, the programmable logic controller controls the contactor to open, cuts off the compensation capacitor and keeps the air source heat pump to continue to reduce power until the air source heat pump stops; The programmable logic controller sends a shutdown instruction to the gas generator set to control the gas generator set to shut down.

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