Multi-heat-source hot water system based on terminal requirements and control method

Abstract

The invention belongs to the technical field of waste heat recovery of cigarette factories, and particularly relates to a multi-heat-source hot water system based on terminal requirements and a control method.The multi-heat-source hot water system comprises a water source heat pump unit, the water source heat pump unit is connected with a transfer water tank through a pipeline, and the transfer water tank is connected with the water source heat pump unit through a pipeline; the transfer water tank is connected with the constant-pressure water supply pump through a pipeline, the constant-pressure water supply pump is connected with the steam-water heat exchanger through a pipeline, and the steam-water heat exchanger is connected with the combined air conditioner through a pipeline. The combined air conditioner is connected with the transfer water tank through a pipeline. According to the technical scheme, the heat supply proportion of the water source heat pump and the steam-water heat exchanger can be dynamically and reasonably allocated through the transfer water tank by taking economic operation as the primary target according to the tail end requirement, and the steam-water heat exchanger can be cut off and the pipeline resistance and heat loss can be reduced on the premise that the output capacity of the water source heat pump is sufficient.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste heat recovery in tobacco factories, and in particular relates to a multi-heat source hot water system based on terminal demand and a control method. Background Art

[0002] Cigarette manufacturers generate a lot of waste heat during the production process. If this waste heat is not used, it will not only cause energy waste, but also cause thermal pollution to the environment. Therefore, cigarette manufacturers should actively explore waste heat recovery and utilization technology, convert waste heat into useful energy, improve energy efficiency, reduce production costs, and achieve sustainable development. At the same time, cigarette manufacturers have a large demand for heating in production and life in winter. The use of heat pump technology to recycle waste heat in the cigarette production process and improve its quality for heating in production and life can greatly reduce energy waste and significantly improve energy efficiency.

[0003] The time and speed of industrial waste heat generation are affected by production plans, while the heating demand for production and life is mainly affected by process parameters and weather. It is difficult to achieve an organic unity between the two. Usually, a water source heat pump is connected in series with a steam-water heat exchanger for series heating. The water temperature is used as the control target, the water source heat pump is used first, and the steam plate heat exchanger is used for temperature compensation. This method has a certain energy-saving effect, but the rationality of the water temperature setting, the misalignment of the water source heat pump's heating capacity and the terminal heating demand in the time dimension, can easily lead to unnecessary opening of the steam-water heat exchanger, making it difficult to achieve efficient use of waste heat and minimize the use of fossil energy. At the same time, the long-term water flow of the steam-water heat exchanger increases the power consumption and heat loss of the water pump. Summary of the invention

[0004] The object of the present invention is to provide a multi-heat source hot water system and a control method based on terminal demand to solve the problems existing in the above-mentioned background technology.

[0005] To achieve the above objectives, this application is implemented through the following technical solutions:

[0006] A multi-heat source hot water system based on terminal demand, comprising a water source heat pump unit, wherein the water outlet of the water source heat pump unit is connected to the heating water inlet of a transfer water tank through a first pipeline, and the heating water return port of the transfer water tank is connected to the water inlet of the water source heat pump unit through a second pipeline;

[0007] The hot water outlet of the transfer water tank is connected to the inlet of the constant pressure water supply pump through the third pipeline, the outlet of the constant pressure water supply pump is connected to the water inlet of the steam-water heat exchanger through the fourth pipeline, and the water outlet of the steam-water heat exchanger is connected to the water inlet of the combined air conditioner through the fifth pipeline; the outlet of the constant pressure water supply pump is connected to the fifth pipeline through the sixth pipeline, and the water outlet of the combined air conditioner is connected to the hot water return port of the transfer water tank through the seventh pipeline;

[0008] The steam inlet of the steam-water heat exchanger is connected to the steam pipeline, and the condensate outlet is connected to the condensate pipeline;

[0009] A water tank temperature sensor is provided on the transfer water tank, a heat pump unit electric valve is provided on the second pipeline, a heat exchanger electric valve is provided on the fifth pipeline, a short-circuit electric valve is provided on the sixth pipeline, and an air-conditioning electric valve is provided on the fifth pipeline near the water inlet of the combined air conditioner.

[0010] Furthermore, a circulation pump is also arranged on the second pipeline.

[0011] Furthermore, a water supply temperature sensor is provided on the fifth pipeline.

[0012] Furthermore, it also includes a controller, which is respectively connected to the water tank temperature sensor, the short-circuit electric valve, the heat exchanger electric valve, the water supply temperature sensor, the air-conditioning electric valve, the heat pump unit electric valve, the constant pressure water supply pump and the circulation pump via electrical signals.

[0013] Furthermore, the hot water of the multi-heat source hot water system includes the following three flow paths:

[0014] The first flow path is that the hot water passes through the transfer water tank, the constant pressure water supply pump, the steam-water heat exchanger, the combined air conditioner and then returns to the transfer water tank;

[0015] The second flow path is that the hot water enters the constant pressure water supply pump from the transfer water tank, and then part of it enters the steam-water heat exchanger and then enters the combined air conditioner, and the other part directly enters the combined air conditioner, and then returns to the transfer water tank from the combined air conditioner;

[0016] The third flow path is that the hot water enters the constant pressure water supply pump from the transfer water tank, now directly enters the combined air conditioner, and then returns to the transfer water tank from the combined air conditioner.

[0017] A control method for a multi-heat source hot water system based on terminal demand according to any one of the above items comprises the following steps:

[0018] S1. The process system is running and generates process waste heat. The water source heat pump unit is interlocked and started. The heating agent is driven by the circulating pump to heat the hot water in the transfer water tank, and the upper limit TH and the lower limit TL of the transfer water tank temperature are set.

[0019] S2. Use the average opening of the electric valve of the combined air conditioner X%, the opening of the electric valve of the steam-water heat exchanger Y%, and the temperature T of the transfer water tank as data sources to determine if , it is determined that the transfer water tank has insufficient heating capacity, and the process goes to step S3. , it is determined that the heating capacity of the transfer water tank is sufficient, and the process goes to step S4;

[0020] S3, the short-circuit electric valve is closed, the heat exchanger electric valve is opened, and the opening of the heat exchanger electric valve is controlled by the average opening of the air conditioning electric valve of the combined air conditioner as the control target to perform real-time PID adjustment to compensate for the terminal heating demand;

[0021] S4, the short-circuit electric valve is fully opened, the heat exchanger electric valve is closed, and the hot water in the transfer water tank meets the terminal heating demand.

[0022] Further, in step S2, the average opening degree X% of the electric valve of the combined air conditioner is obtained by the sliding window average calculation method, and the specific steps are:

[0023] Assume that the total width of the sliding window is i seconds, and collect data once every set time interval to form Data set, then , when entering the next data collection, Data is pushed into the stack, then .

[0024] The beneficial effects of the present invention are:

[0025] This technical solution can, based on terminal demand and with economic operation as the primary goal, smooth out the imbalance between supply and demand through the transfer water tank, dynamically and reasonably adjust the heating ratio of the water source heat pump and the steam-water heat exchanger, and can, on the premise that the output capacity of the water source heat pump is sufficient, remove the steam-water heat exchanger to reduce pipeline resistance and heat loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of a multi-heat source hot water system based on terminal demand according to the present invention.

[0027] Figure 2 This is a logic diagram of the control method of the present invention.

[0028] Description of reference numerals:

[0029] 1. Water source heat pump unit; 2. First pipeline; 3. Transfer water tank; 4. Water tank temperature sensor; 5. Third pipeline; 6. Constant pressure water supply pump; 7. Fourth pipeline; 8. Steam-water heat exchanger; 9. Heat exchanger electric valve; 10. Fifth pipeline; 11. Water supply temperature sensor; 12. Short-circuit electric valve; 13. Sixth pipeline; 14. Combined air conditioner; 15. Air conditioner electric valve; 16. Seventh pipeline; 17. Second pipeline; 18. Circulation pump, 19. Heat pump unit electric valve. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings. The following embodiments are merely exemplary and can only be used to explain and illustrate the technical solution of the present invention, but cannot be construed as limiting the technical solution of the present invention.

[0031] In this application, the water source heat pump unit: This unit is the core of the system and is linked to the process system. If the process system is running and process waste heat is generated, the heat pump unit will start and recover the waste heat to heat the hot water in the transfer water tank through the condensing side.

[0032] Transfer water tank: The transfer water tank is used to store hot water to ensure the continuity and stability of hot water supply. A temperature sensor is installed in the transfer water tank to monitor the water temperature in real time and provide feedback for the heat pump unit.

[0033] Constant pressure water supply device: This device ensures the constancy of the system water supply pressure to avoid the stability of hot water supply due to pressure fluctuations. In this application, it is a constant pressure water supply pump.

[0034] Steam-water heat exchanger: When the hot water generated by the waste heat recovery water source heat pump unit cannot meet the terminal hot water heating demand, steam heating is used to supplement heat energy through the steam-water heat exchanger.

[0035] Short-circuit electric valve: When the hot water in the transfer water tank is sufficient to meet the terminal heating demand, the short-circuit electric valve can be used to quickly short-circuit the steam-water heat exchanger to reduce pipeline losses and heat loss in the steam-water heat exchanger.

[0036] Temperature sensor: Multiple temperature sensors are distributed in different locations in the system to monitor the temperature of each link in real time and provide data support for the automatic control of the system.

[0037] like Figure 1 As shown, the present application provides a multi-heat source hot water system based on terminal demand, including a water source heat pump unit 1, the water outlet of the water source heat pump unit 1 is connected to the heating water inlet of the transfer water tank 3 through a first pipeline 2, and the heating return water port of the transfer water tank 3 is connected to the water inlet of the water source heat pump unit 1 through a second pipeline 17.

[0038] The hot water outlet of the transfer water tank 3 is connected to the inlet of the constant pressure water supply pump 6 through the third pipeline 5, the outlet of the constant pressure water supply pump 6 is connected to the water inlet of the steam-water heat exchanger 8 through the fourth pipeline 7, and the water outlet of the steam-water heat exchanger 8 is connected to the water inlet of the combined air conditioner 14 through the fifth pipeline 10; the outlet of the constant pressure water supply pump 6 is connected to the fifth pipeline 10 through the sixth pipeline 13, and the water outlet of the combined air conditioner 14 is connected to the hot water return port of the transfer water tank 3 through the seventh pipeline 16; the steam inlet of the steam-water heat exchanger 8 is connected to the steam pipeline, and the condensate outlet is connected to the condensate pipeline.

[0039] A water tank temperature sensor 4 is provided on the transfer water tank 3, a heat pump unit electric valve 19 is provided on the second pipeline 17, a heat exchanger electric valve 9 is provided on the fifth pipeline 10, a short-circuit electric valve 12 is provided on the sixth pipeline 13, and an air-conditioning electric valve 15 is provided at the water inlet of the fifth pipeline 10 near the combined air conditioner 14.

[0040] In the present application, a circulation pump 18 is further provided on the second pipeline 17 ; and a water supply temperature sensor 11 is provided on the fifth pipeline 10 .

[0041] The present application also includes a controller, which is respectively connected to the water tank temperature sensor, the short-circuit electric valve, the heat exchanger electric valve, the water supply temperature sensor, the air conditioner electric valve, the heat pump unit electric valve, the constant pressure water supply pump and the circulation pump by electrical signals.

[0042] In this application, the hot water of the multi-heat source hot water system includes the following three flow paths:

[0043] The first flow path is that the hot water passes through the transfer water tank, the constant pressure water supply pump, the steam-water heat exchanger, and the combined air conditioner in sequence and then returns to the transfer water tank.

[0044] The second flow path is that the hot water enters the constant pressure water supply pump from the transfer water tank, and then part of it enters the steam-water heat exchanger and then enters the combined air conditioner, and the other part directly enters the combined air conditioner, and then returns to the transfer water tank from the combined air conditioner.

[0045] The third flow path is that the hot water enters the constant pressure water supply pump from the transfer water tank, now directly enters the combined air conditioner, and then returns to the transfer water tank from the combined air conditioner.

[0046] The waste heat recovery type water source heat pump unit is linked to the process system (production line). If the process system is running and generates process waste heat, the water source heat pump unit is started for recovery, and the hot water in the transfer water tank is heated on the condensing side. The transfer water tank is equipped with a water tank temperature sensor. The operating load of the water source heat pump unit is controlled by the maximum limit of the transfer water tank temperature, and real-time PID adjustment is performed on the control target. Through the above technical route and the setting of the transfer water tank, the transfer storage and peak shaving of industrial waste heat are realized.

[0047] The hot water in the transfer water tank is supplied to the heating section of the combined air conditioner at the end through a constant pressure water supply device (hot water supply pump) to meet the heating needs of the production and living environment. The on-site ambient temperature is controlled by adjusting the opening of the air-conditioning electric valve of the combined air-conditioning heating section to adjust the amount of hot water passing through the heating section.

[0048] like Figure 2 As shown, the present application also provides a control method for a multi-heat source hot water system based on terminal demand, in which the hot water in the transfer water tank is supplied to the heating section of the combined air conditioner at the terminal through a hot water supply pump to meet the heating needs of the production and living environment, and the on-site ambient temperature is controlled by adjusting the opening of the air-conditioning electric valve of the heating section of the combined air-conditioner to adjust the amount of hot water passing through the heating section.

[0049] S1. The process system is running and generates process waste heat. The water source heat pump unit is interlocked and started. The heating agent is driven by the circulating pump to heat the hot water in the transfer water tank, and the upper limit value T of the transfer water tank temperature is set. H , the lower limit of the transfer tank temperature T L .

[0050] S2, the average valve opening of the electric valve of the combined air conditioner , Opening degree of heat exchanger electric valve of steam-water heat exchanger And the transfer tank temperature Assume that the average high-load opening limit of the electric valve of the combined air conditioner is , the low load opening limit is , transfer water tank temperature lower limit ,when , the signal of insufficient heating capacity of the transfer water tank is , a signal that the transfer tank has sufficient heating capacity ;when , the rising edge triggers the setting of the transfer water tank heating capacity sufficient signal , reset the transfer water tank heating capacity insufficient signal .

[0051] The average opening of the air-conditioning electric valve of the combined air conditioner is needed to reflect the adaptability of the heating system to the terminal heating demand. When the average opening of the air-conditioning electric valve of the combined air conditioner is too large or even fully open, it means that the margin of the heating system to respond to the terminal heating demand is insufficient or even insufficient. When the average opening of the air-conditioning electric valve of the combined air conditioner is too small, it means that the terminal heating demand is small. Suppose the average valve opening of the air-conditioning electric valve of the combined air conditioner is , which is calculated by the sliding window (the window here refers to the inner diameter of the air conditioning electric valve) average calculation method: Assume that the total width of the sliding window Seconds, collect data once per second to form Data, then , refreshed once per second, when entering the next second, Data is pushed into the stack, then .

[0052] S3. When the heating capacity insufficient signal of the transfer water tank of the series-connected steam-water heat exchanger is 1, the short-circuit electric valve is closed and the steam-water heat exchanger is put into use. The steam consumption is adjusted by the heat exchanger electric valve of the steam-water heat exchanger. The average valve opening of the air-conditioning electric valve of the combined air-conditioner is used as the control target for real-time PID adjustment to compensate and meet the terminal heating demand.

[0053] S4. When the heating capacity signal of the transfer water tank is 1, the short-circuit electric valve of the series-connected steam-water heat exchanger is fully opened to short-circuit the steam-water heat exchanger to reduce the power consumption of the water pump and heat loss.

[0054] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A multi-heat source hot water system based on terminal demand, characterized in that: It includes a water source heat pump unit, wherein the water outlet of the water source heat pump unit is connected to the heating water inlet of the transfer water tank through a first pipeline, and the heating water return port of the transfer water tank is connected to the water inlet of the water source heat pump unit through a second pipeline; The hot water outlet of the transfer water tank is connected to the inlet of the constant pressure water supply pump through the third pipeline, the outlet of the constant pressure water supply pump is connected to the water inlet of the steam-water heat exchanger through the fourth pipeline, and the water outlet of the steam-water heat exchanger is connected to the water inlet of the combined air conditioner through the fifth pipeline; the outlet of the constant pressure water supply pump is connected to the fifth pipeline through the sixth pipeline, and the water outlet of the combined air conditioner is connected to the hot water return port of the transfer water tank through the seventh pipeline; The steam inlet of the steam-water heat exchanger is connected to the steam pipeline, and the condensate outlet is connected to the condensate pipeline; A water tank temperature sensor is provided on the transfer water tank, a heat pump unit electric valve is provided on the second pipeline, a heat exchanger electric valve is provided on the fifth pipeline, a short-circuit electric valve is provided on the sixth pipeline, and an air-conditioning electric valve is provided on the fifth pipeline near the water inlet of the combined air conditioner.

2. The multi-heat source hot water system based on terminal demand according to claim 1, characterized in that: A circulation pump is also arranged on the second pipeline.

3. The multi-heat source hot water system based on terminal demand according to claim 1, characterized in that: A water supply temperature sensor is provided on the fifth pipeline.

4. The multi-heat source hot water system based on terminal demand according to claim 3 is characterized in that: It also includes a controller, which is respectively connected to the water tank temperature sensor, the short-circuit electric valve, the heat exchanger electric valve, the water supply temperature sensor, the air conditioner electric valve, the heat pump unit electric valve, the constant pressure water supply pump and the circulation pump through electrical signals.

5. The multi-heat source hot water system based on terminal demand according to claim 1, characterized in that: The hot water in the multi-heat source hot water system includes the following three flow paths: The first flow path is that the hot water passes through the transfer water tank, the constant pressure water supply pump, the steam-water heat exchanger, the combined air conditioner and then returns to the transfer water tank; The second flow path is that the hot water enters the constant pressure water supply pump from the transfer water tank, and then part of it enters the steam-water heat exchanger and then enters the combined air conditioner, and the other part directly enters the combined air conditioner, and then returns to the transfer water tank from the combined air conditioner; The third flow path is that the hot water enters the constant pressure water supply pump from the transfer water tank, now directly enters the combined air conditioner, and then returns to the transfer water tank from the combined air conditioner.

6. A control method for a multi-heat source hot water system based on terminal demand according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. The process system is running and generates process waste heat. The water source heat pump unit is interlocked and started. The heating agent is driven by the circulating pump to heat the hot water in the transfer water tank, and the upper limit value T of the transfer water tank temperature is set. H , the lower limit of the transfer tank temperature T L ; S2, using the average opening of the electric valve of the combined air conditioner X%, the opening of the electric valve of the steam-water heat exchanger Y%, and the temperature T of the transfer water tank as data sources to determine if , it is determined that the heating capacity of the transfer water tank is insufficient, and the process goes to step S3. , it is determined that the heating capacity of the transfer water tank is sufficient, and the process goes to step S4; S3, the short-circuit electric valve is closed, the heat exchanger electric valve is opened, and the opening of the heat exchanger electric valve is controlled by the average opening of the air conditioning electric valve of the combined air conditioner as the control target to perform real-time PID adjustment to compensate for the terminal heating demand; S4, the short-circuit electric valve is fully opened, the heat exchanger electric valve is closed, and the hot water in the transfer water tank meets the terminal heating demand.

7. The control method of a multi-heat source hot water system based on terminal demand according to claim 6, characterized in that: In step S2, the average opening degree X% of the electric valve of the combined air conditioner is obtained by the sliding window average calculation method, and the specific steps are as follows: Assume that the total width of the sliding window is i seconds, and collect data once every set time interval to form Data set, then , when entering the next data collection, Data is pushed into the stack, then .

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