Heat exchange system

Abstract

The utility model relates to a heat exchange system which comprises a fan, a heat exchanger, a first temperature sensing unit, a control unit and a water tank, an air inlet is located at the bottom of the heat exchanger, an air outlet is located at the top of the heat exchanger, a first water inlet is configured to be connected with an external water supply pipe, and a water pipe is configured to conduct heat exchange between an external water source and smoke. The first water outlet is configured to discharge water subjected to heat exchange; the first temperature sensing unit is configured to detect the temperature of water from the heat exchanger; and the control unit is configured to adjust the air inlet amount of the fan according to the water temperature. The water tank includes a first region and a second region separated by a partition plate. The heat exchange system can recover heat in the flue gas and reduce thermal pollution to the environment.

Description

Technical Field

[0001] The utility model relates to the field of gypsum board production, and more specifically, to a heat exchange system. Background Art

[0002] Gypsum board is an important building material, consisting of gypsum slurry sandwiched between two layers of facing paper. The production process for gypsum board includes slurry mixing, board forming, cutting, and drying. During the drying process, steam is typically used to heat air, which is then used to dry the gypsum board. The hot air after drying the gypsum board contains residual heat.

[0003] Furthermore, due to the high moisture content of gypsum boards before drying, the exhaust gas from the dryer contains a large amount of water vapor. The temperature of the exhaust gas can reach 130-160°C. Currently, the exhaust gas from the dryer is usually discharged directly into the atmosphere, which increases energy waste and causes thermal pollution to the environment. Utility Model Content

[0004] In order to solve at least part of the above problems, the present invention proposes a heat exchange system that can recover heat in flue gas and reduce thermal pollution to the environment.

[0005] Specifically, the first aspect of the present invention proposes a heat exchange system, including a fan, a heat exchanger, a first temperature sensing unit, and a control unit, wherein the fan is connected to the heat exchanger, and the fan is configured to introduce the flue gas into the heat exchanger; the heat exchanger includes an air inlet, an air outlet, a first water inlet, a water pipe and a first water outlet, the air inlet is located at the bottom of the heat exchanger, the air outlet is located at the top of the heat exchanger, the first water inlet is configured to be connected to an external water supply pipe and introduce an external water source into the water pipe, the water pipe is configured to exchange heat between the external water source and the flue gas, the outside of the water pipe is configured to contact the flue gas, the inside of the water pipe is configured to accommodate the external water source, and the first water outlet is configured to The exchanged water is discharged, and the air outlet is configured to discharge the exhaust gas that has undergone heat exchange; the first temperature sensing unit is configured to detect the temperature of the water that has undergone heat exchange; and the control unit is connected to the first temperature sensing unit and the fan, and the control unit is configured to adjust the air intake of the fan according to the temperature of the water that has undergone heat exchange; and the water tank includes: a partition, which divides the water tank into a first area and a second area, and the bottom of the first area is connected to the bottom of the second area; and a second water inlet and a second water outlet, the second water inlet is connected to the first water outlet, the second water inlet is located above the first area, and the second water outlet is located below the first area, and the second water outlet is configured to supply water to the downstream production line.

[0006] In one embodiment of the present invention, a first frequency converter is further included, wherein the first frequency converter is communicatively coupled to the control unit and the fan, and the fan can be precisely adjusted via the frequency converter.

[0007] In one embodiment of the present invention, a water pump and a second temperature sensing unit are further included. The water tank further includes a third water outlet, wherein the third water outlet is located below the second area. The water inlet of the water pump is connected to the third water outlet and the external water supply pipe, and the water outlet of the water pump is connected to the first water inlet. The second temperature sensing unit is configured to detect the water temperature in the second area. The control unit is further configured to adjust the water intake of the water pump based on the water temperature in the second area. The water pump can promote water circulation in the water tank, thereby improving water temperature uniformity.

[0008] In one embodiment of the present invention, a second frequency converter is further included, wherein the second frequency converter is communicatively coupled to the control unit and the water pump.

[0009] In one embodiment of the present invention, the system further includes an induced air duct connected to the fan and configured to receive the smoke from the external duct; and an exhaust duct connected to the air outlet and configured to discharge the exhaust gas to the external duct; wherein the induced air duct is provided with a first valve and the exhaust duct is provided with a second valve, the first valve being configured to adjust the flow rate of the smoke, and the second valve being configured to adjust the flow rate of the exhaust gas. The valves provided on the induced air duct and the exhaust duct can achieve good control of the smoke.

[0010] In one embodiment of the present invention, the water tank further includes a third water inlet, the system further includes a third valve and a liquid level sensing unit, the third water inlet is connected to the third valve, the third valve is an automatic opening control valve, the third valve is configured to be connected to the external water supply pipe and control the water inlet of the external water supply pipe, and the liquid level sensing unit is configured to detect the liquid level of the water tank.

[0011] In one embodiment of the present invention, a third temperature sensing unit is further included, wherein the third temperature sensing unit is configured to detect the temperature of the flue gas, and the control unit is further configured to adjust the opening state of the fan according to the temperature of the flue gas.

[0012] In one embodiment of the present invention, the third temperature sensing unit is located in the main duct or the induced air duct.

[0013] In one embodiment of the present invention, the water pipe includes a plurality of U-shaped tube units, which are sequentially connected to form a channel, wherein each U-shaped tube unit includes one or more fins. The arrangement of the U-shaped tube units and fins can increase the heat exchange area, thereby improving heat exchange efficiency.

[0014] In one embodiment of the present invention, the heat exchanger further comprises a water extraction pipe located near the water pipe and configured to collect water generated by condensation of the flue gas. The condensed water collected by the water extraction pipe can be used in other production processes.

[0015] In addition, the second aspect of the present invention relates to a control method applied to any one of the various embodiments of the first aspect of the content of the present invention, including obtaining the set temperature of the water that has undergone heat exchange; obtaining the detected temperature of the water that has undergone heat exchange; and controlling the air intake volume of the fan based on the difference between the set temperature of the water that has undergone heat exchange and the detected temperature of the water that has undergone heat exchange.

[0016] In one embodiment of the present invention, the method further includes obtaining a set temperature of the flue gas; obtaining a detected temperature of the flue gas; and turning on the fan when the detected temperature of the flue gas is greater than or equal to the set temperature of the flue gas.

[0017] In one embodiment according to the contents of the present invention, it also includes, when the detected temperature of the water that has undergone heat exchange is greater than or equal to the set temperature of the water that has undergone heat exchange, opening the water pump and the valve between the water pump and the water tank; obtaining the detected temperature of the second area; and adjusting the water inlet flow of the water pump based on the difference between the detected temperature of the second area and the set temperature of the water that has undergone heat exchange.

[0018] In one embodiment according to the content of the present invention, it also includes opening the third valve; obtaining the set liquid level of the water tank; obtaining the detected liquid level of the water tank; and when the detected liquid level of the water tank is higher than or equal to the set liquid level of the water tank, closing the third valve.

[0019] In addition, the third aspect of the present invention relates to an electronic device, which includes a memory and a processor, wherein the memory stores computer-readable instructions, and when the computer-readable instructions are executed by the processor, the processor implements the control method described in any one of the embodiments of the second aspect of the present invention.

[0020] Furthermore, the fourth aspect of the present invention relates to a computer-readable storage medium having computer-executable instructions stored thereon, and the computer-executable instructions are used to execute the control method described in any one of the embodiments of the second aspect of the present invention.

[0021] Finally, the fifth aspect of the present invention relates to a computer program product, which is tangibly stored on a computer-readable storage medium and includes computer-executable instructions, which, when executed by at least one processor, cause the at least one processor to perform the control method according to any one of the embodiments of the second aspect of the present invention.

[0022] In summary, the heat exchange system and control method according to the technical solution of the present invention utilizes an air-to-water heat exchanger to treat the flue gas generated during the gypsum board drying process. The high-temperature flue gas heats the water in the heat exchanger's water pipes, releasing sensible heat, while the high-water content flue gas condenses, releasing latent heat. The hot water and condensed water flowing out of the heat exchanger can be stored for use in other production processes. Therefore, the heat exchange system can recover heat from the flue gas and reduce thermal pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The features, advantages and other aspects of the various embodiments of the present invention will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Several embodiments of the present invention are shown herein in an illustrative and non-limiting manner. In the accompanying drawings:

[0024] Figure 1 FIG. 1 is a schematic structural diagram of an exemplary heat exchange system 100 according to an embodiment of the present invention.

[0025] Figure 2 A schematic structural diagram of a control unit of a heat exchange system according to an embodiment of the present invention is shown.

[0026] Figure 3 A schematic structural diagram of a downstream device in a heat exchange system according to another embodiment of the present invention is shown.

[0027] Figure 4 A schematic structural diagram of a control unit of a heat exchange system according to an embodiment of the present invention is shown.

[0028] Figure 5 A flow chart of a control method 200 for a heat exchange system according to an embodiment of the present invention is shown.

[0029] Figure 6FIG. 2 is a flow chart of a wind turbine control method 210 according to an embodiment of the present invention.

[0030] Figure 7 FIG. 2 is a flow chart of a water pump control method 220 according to an embodiment of the present invention.

[0031] Figure 8 FIG. 2 is a flow chart of a water level control method 230 for a water tank according to an embodiment of the present invention.

[0032] Figure 9 FIG. 1 is a schematic diagram of an electronic device 300 according to another embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following describes in detail various exemplary embodiments of the present invention with reference to the accompanying drawings. Although the exemplary methods and devices described below include software and / or firmware executed on hardware among other components, it should be noted that these examples are merely illustrative and should not be regarded as restrictive. For example, it is contemplated that any or all hardware, software, and firmware components may be implemented exclusively in hardware, exclusively in software, or in any combination of hardware and software. Therefore, although exemplary methods and devices have been described below, it should be readily understood by those skilled in the art that the examples provided are not intended to limit the manner in which these methods and devices are implemented.

[0034] In addition, the flowcharts and block diagrams in the accompanying drawings illustrate possible architectures, functions, and operations of the methods and systems according to various embodiments of the present utility model. It should be noted that the functions marked in the boxes may also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession may actually be executed substantially in parallel, or they may sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the flowchart and / or block diagram, and the combination of boxes in the flowchart and / or block diagram, may be implemented using a dedicated hardware-based system that performs the specified functions or operations, or may be implemented using a combination of dedicated hardware and computer instructions.

[0035] The terms "including," "comprising," and similar terms used in this utility model are open-ended terms, i.e., "including but not limited to," indicating that other contents may also be included. The term "based on" means "based at least in part on." The term "one embodiment" means "at least one embodiment," and the term "another embodiment" means "at least one additional embodiment," etc.

[0036] In the present invention, the terms "first", "second" and the like are not used to limit the order of precedence and the number of components, unless otherwise specified. In the present invention, the meaning of "plurality" refers to two or more, unless otherwise clearly and specifically defined. In addition, in the present invention, unless otherwise clearly and specifically defined, the terms "installation", "connection", "attachment" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral whole; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in this article can be understood according to the specific circumstances.

[0037] refer to Figure 1 , Figure 1 The schematic diagram of the structure of an exemplary heat exchange system 100 applicable to an embodiment of the present invention is shown. The exemplary heat exchange system 100 can receive flue gas from an external pipe 10 through an induced air duct 110 and discharge exhaust gas through an exhaust duct 120. The exemplary heat exchange system 100 (hereinafter referred to as "system 100") includes a fan 130, a heat exchanger 140, a first temperature sensing unit 150, a control unit 160 ( Figure 1 Not shown) and water tank 12.

[0038] Figure 1 The system 100 is shown as being connected to an external duct 10 and a dryer 11. The external duct 10 is connected to the dryer 11. The dryer 11 is used to dry gypsum boards and exhaust fumes through the external duct 10. An induced draft duct 110 is connected to the external duct 10 at one end and to a fan 130 at the other end.

[0039] The induced draft duct 110 is connected to the external duct 10, and the induced draft duct 110 is used to receive flue gas from the external duct. The external duct 10 is the main duct, and the induced draft duct 110 draws in part of the flue gas from the main duct and transmits this part of the flue gas to the fan 130. The fan 130 is connected to the induced draft duct 110 and the heat exchanger 140. The fan 130 is used to introduce the flue gas into the heat exchanger. The inlet of the fan 130 is connected to the induced draft duct 110, and the outlet of the fan 130 is connected to the heat exchanger 140. In some embodiments, valves (not shown) may be provided on the induced draft duct and the exhaust duct to achieve good control of the flue gas. For example, a first valve is provided on the induced draft duct, and a second valve is provided on the exhaust duct. The first valve is used to adjust the flow rate of the flue gas, and the second valve is used to adjust the flow rate of the exhaust gas. In some examples, the first valve and the second valve may be butterfly valves or ball valves.

[0040] Heat exchanger 140 includes an air inlet 141 and an air outlet 142. Air inlet 141 is located at the bottom of heat exchanger 140, while air outlet 142 is located at the top of heat exchanger 140. Air outlet 142 is connected to exhaust duct 120. Flue gas flows from the lower area of ​​heat exchanger 140 through the upper area to complete heat exchange. The exhaust gas after heat exchange is discharged through exhaust duct 120.

[0041] The heat exchanger 140 also includes a water inlet 143 (first water inlet), a water pipe 144 and a water outlet 145 (first water outlet). The water inlet 143 is used to connect to an external water pipe to introduce the external water source 13 into the water pipe 144. The water pipe 144 is used to exchange heat between the external water source and the flue gas. The outside of the water pipe 144 is in contact with the flue gas, and the inside of the water pipe 144 accommodates the external water source. The water inside the water pipe 144 does not contact the flue gas. Normal temperature water enters the water pipe from the water inlet 143, and the water in the water pipe exchanges heat with the external high-temperature flue gas to form hot water, which is discharged from the water outlet 145. In some examples, normal temperature water can be municipal water. The temperature of the hot water after heat exchange can be higher than 50°C. The water outlet 145 is used to discharge the hot water. Figure 1 In the example of , hot water can be stored in the water tank 12. The hot water in the water tank 12 can be used in gypsum board production line processes, such as gypsum slurry preparation, face paper making, etc.

[0042] The flue gas generated after drying the gypsum board includes not only the residual heat from the hot air after drying, but also the latent heat of vaporization of the water vapor after the moisture in the board evaporates. After the flue gas passes through the heat exchanger 140, the residual heat from the hot air heats the room-temperature water in the water pipe, transferring the heat to the water. In addition, the moisture in the flue gas can be condensed, thereby recovering the latent heat. The temperature of the condensed water can reach 80°C. In some examples, the condensed water can be retained in the heat exchanger to heat the water pipes therein. In some examples, the condensed water can also be extracted for use in the gypsum board production line process. In some examples, the heat exchanger 140 may also include a water extraction pipe, located near the water pipe 144, for collecting and discharging the water generated by the condensation of the flue gas. In some examples, the condensed water discharged from the water extraction pipe can be used in the gypsum board production line process.

[0043] In some embodiments, the water pipe 144 in the heat exchanger 140 may have a serpentine shape to increase the contact area with the flue gas. For example, the water pipe may include multiple U-shaped tube units, which are sequentially connected to form a channel. In some examples, each U-shaped tube unit may include one or more fins, which may be located on the outside and / or inside of the U-shaped tube unit. The provision of fins can increase the heat exchange area and improve heat exchange efficiency.

[0044] After the flue gas undergoes heat exchange, the heat-exchanged exhaust gas is discharged through the exhaust port 142. The temperature of the exhaust gas can be lower than 50°C. The exhaust duct 120 is connected to the external duct 10 and is used to discharge the exhaust gas to the external duct 10.

[0045] The first temperature sensing unit 150 is located at the water outlet 145 of the heat exchanger 140 or somewhere downstream of the water outlet 145. The first temperature sensing unit 150 is used to detect the temperature of the hot water exiting the heat exchanger. In some examples, the temperature sensing unit can be one or more of a thermocouple, a thermistor, a resistance temperature detector (RTD), an analog thermometer IC, and a digital thermometer IC.

[0046] The control unit 160 is communicatively connected to the first temperature sensing unit 150 and the fan 130. In some examples, the control unit 160 can receive an analog signal from the first temperature sensing unit 150 and convert it into a digital signal, or directly receive a digital signal from the first temperature sensing unit 150 and read the switch state or pulse quantity, or use a specific communication interface to receive data from the first temperature sensing unit 150, or connect to the first temperature sensing unit 150 through a bus interface template and read the corresponding sensed data through addresses and commands.

[0047] The control unit 160 controls the motor of the fan through the output module. In some embodiments, the air intake can be adjusted by adjusting the speed of the fan. When the temperature of the water after heat exchange needs to be increased, the speed of the fan can be increased to increase the air intake. When the temperature of the water after heat exchange needs to be reduced, the speed of the fan can be reduced to reduce the air intake. The control unit 160 is used to adjust the air intake of the fan 130 according to the temperature of the water after heat exchange. For example, the temperature of the water treated by the heat exchanger is detected by the temperature sensing unit 150 and converted into an analog input signal. After analog-to-digital conversion, the analog signal can be compared with a predetermined value in the control unit 160, and then converted into an analog output signal through digital-to-analog conversion. The control unit can control and adjust the speed of the fan based on the analog output signal.

[0048] In some examples, the system 100 further includes a frequency converter 180 (a first frequency converter) to precisely regulate the fan. Figure 2 The following is a schematic diagram illustrating the structure of a control unit for a heat exchange system according to one embodiment of the present invention. The control unit 160 is communicatively coupled to the sensing unit 150 and the inverter 180, and the inverter 180 is communicatively coupled to the fan 130. In some examples, the inverter 180 may be integrated with the control unit 160 or the fan 130. The sensing unit 150 is used to detect the outlet water temperature of the heat exchanger. The control unit 160 receives feedback signals from the sensing unit 150 and controls the output frequency of the inverter 180 to control the motor speed of the fan 130.

[0049] In some examples, direct torque control can be used in inverters to control speed. Real-time motor current detection and feedback are used to adjust the inverter's switching state, achieving motor torque control. In some examples, vector control can be used in inverters to control speed. By decomposing the motor's stator current, the excitation current and torque current are derived, allowing for separate control.

[0050] The frequency converter 180 can convert AC power of fixed frequency and voltage into AC power of variable frequency and variable voltage, thereby adjusting the operating speed of the motor connected to the frequency converter. In some examples, an open-loop speed control method can be used in the frequency converter to control the speed. The motor speed is regulated by adjusting the output frequency of the inverter. This method has a simple structure but low accuracy. In some examples, a closed-loop speed control method can be used in the frequency converter to control the speed. A speed sensor is set to detect the actual speed of the motor in real time. It is then compared with the target speed to calculate an error signal. After processing the error signal, the output frequency of the inverter is adjusted to accurately regulate the motor speed.

[0051] Specifically, the inverter 180 first converts the input AC power into DC power via an internal rectifier. Using the switching elements within the inverter and pulse-width modulation (PWM) technology, the DC power is converted into variable-frequency AC power. By controlling the switching frequency and duty cycle of the switches, AC output with varying frequencies and amplitudes is generated. The inverted variable-frequency AC power is then fed to the motor, thereby controlling its operating speed. By varying the output frequency, the motor's speed can be precisely controlled.

[0052] In some examples, the water tank 12 can not only store the hot water produced by the heat exchanger, but also reduce water temperature fluctuations through hard insulation. Figure 3 The following is a schematic diagram showing the structure of the downstream device of the heat exchange system according to an embodiment of the present invention. Figure 3 In the example of FIG. 1 , the system 100 may further include a temperature-zoned water tank 121 .

[0053] refer to Figure 3 Water tank 121 includes a partition 122. The partition divides the partition water tank into two left and right areas, namely, a first area I and a second area II. The bottom of the first area I is connected to the bottom of the second area II. Water tank 121 also includes a water inlet 123 (second water inlet) and a water outlet 124 (second water outlet).

[0054] The water inlet 123 is connected to the water outlet 145 of the heat exchanger 140. The water inlet 123 is located above the first area I, and the water outlet 124 is located below the first area I. The water inlet 123 is used to receive hot water from the heat exchanger and input it into the water tank 121. The water outlet 124 is used to supply water to the downstream production line. Figure 3 As can be seen, water tank 121 is hard-isolated by partition 122. When hot water is introduced into first region I through water inlet 123, the water already in first region I flows through the bottom portion of the connection between the two regions into second region II. In some examples, water tank 121 can have a capacity of up to 10 tons. This arrangement buffers the hot water supply and existing cold water in the tank, thereby reducing temperature fluctuations within the tank.

[0055] In some embodiments, the system 100 may further include a water pump device that can circulate the water in the water tank. Figure 3 System 100 includes a water pump 170. Water tank 121 also includes a water outlet 125 (third water outlet), which is located below second region II. The water inlet of water pump 170 is connected to water outlet 125 and an external water supply pipe, and the water outlet of water pump 170 is connected to water inlet 143 of heat exchanger 140.

[0056] The system 100 further includes a second temperature sensing unit 151 ( Figure 3 (not shown). Second temperature sensing unit 151 can be located in second region II of water tank 121 to detect the water temperature in second region II. Control unit 160 can also be configured to adjust the water intake of water pump 170 based on the water temperature in second region II detected by second temperature sensing unit 151. In some examples, system 100 also includes fourth temperature sensing unit 152, located outside water inlet 143 of heat exchanger 140, to detect the temperature of water entering heat exchanger 140.

[0057] In some examples, the system 100 further includes a frequency converter 181 (a second frequency converter) to precisely regulate the water pump 170 . Figure 4The schematic diagram of the structure of the control unit of the heat exchange system of one embodiment of the present invention is shown. The control unit 160 is connected to a variety of sensing units. For example, the sensing unit 151 and the sensing unit 152. In some examples, the control unit can also be connected to the sensing unit 150. In addition, a pressure sensing unit 154 is provided outside the water inlet 143 of the heat exchanger 140, and a pressure sensing unit 153 is provided outside the water outlet 145 of the heat exchanger 140. These two pressure sensing units are used to detect the water pressure of the water entering and leaving the heat exchanger. The control unit 160 is communicatively coupled to the frequency converter 181, and the frequency converter 181 is communicatively coupled to the water pump 170. In some examples, the frequency converter 181 can be integrated with the control unit 160 or the water pump 170. The temperature sensing unit 151 is used to detect the water temperature in the second area II, and the temperature sensing unit 152 is used to detect the temperature of the water entering the heat exchanger. The control unit 160 receives feedback signals from the temperature sensing units 151 , 152 and the pressure sensing units 153 , 154 , and controls the output frequency of the inverter 181 to control the motor speed of the water pump 170 to adjust the water intake.

[0058] The inverter 181 can convert fixed-frequency and voltage AC power into variable-frequency and variable-voltage AC power, thereby adjusting the operating speed of the water pump motor connected to the inverter. The water intake of the water pump is adjusted based on the difference between the water temperature detected by the second temperature sensing unit 151 and the set temperature. For example, when the water temperature detected by the temperature sensing unit 151 is lower than the set temperature, the water output from the water outlet 125 can be increased, accelerating the water in the water tank to enter the heat exchanger circulation. When the water temperature detected by the temperature sensing unit 151 is higher than the set temperature, the water output from the water outlet 125 can be reduced or even closed to maintain the water in the water tank near the set temperature. When the water temperature detected by the temperature sensing unit 152 is higher than the set temperature, the water output from the water outlet 125 can be reduced or even closed to maintain the water in the water tank near the set temperature. In some examples, the set temperature here can be the water temperature detected by the temperature sensing unit 150. A valve may be provided between the water outlet 125 and the water pump to adjust the water flow cutoff between the water outlet tank and the water pump. In some examples, the water temperature of the temperature sensing units 150, 151, and 152 may be comprehensively considered to adjust the water intake of the water pump. The control unit 160 regulates the water pump 170 via the inverter 181 to circulate the water in the water tank 121, thereby improving the uniformity of the water temperature within the water tank. The control unit 160 may also control the inverter 181 to adjust the water pump based on the feedback signals from the pressure sensing units 153 and 154 to maintain the water pressure stability within the system 100.

[0059] In some embodiments, before the hot water in the heat exchange water tank enters the water tank, part of the water in the water tank can be connected to the municipal water source. Figure 3The water tank 121 also includes a water inlet 126 (third water inlet) for connecting water from the outside so that the water tank 121 maintains a certain water level before the heat exchange system works. In some examples, the system may also include a third valve (not shown in the figure) and a liquid level sensing unit (not shown in the figure). The water inlet 126 is connected to the third valve, and the third valve is connected to the external water supply pipe and is used to control the water intake of the external water supply pipe. The liquid level sensing unit is used to detect the liquid level of the water tank. In some examples, the third valve is an automatic opening control valve. The size of the opening of the third valve is controlled by the size of the current, and the valve opening increases continuously as the current increases. The control unit can convert the acquired digital quantity into a corresponding analog current to achieve automatic control of the third valve.

[0060] In some embodiments, the system 100 may further include a temperature sensing unit (third temperature sensing unit) for detecting the temperature of the flue gas entering the heat exchanger. In some examples, the third temperature sensing unit may be located in the main duct 10 or the induced draft duct 110. The third temperature sensing unit is used to detect the temperature of the flue gas in the external duct 10 or the induced draft duct 110. The control unit 160 is also configured to adjust the opening state of the fan according to the flue gas temperature detected by the third temperature sensing unit. For example, when the dryer 11 just starts working, the flue gas temperature detected by the third temperature sensing unit is relatively low, for example, below 120°C. The control unit 160 controls the fan not to start. After the dryer 11 has been working for a period of time, the flue gas temperature detected by the third temperature sensing unit is higher than 120°C, and the control unit 160 controls the fan to start working.

[0061] Regarding the heat exchange system 100 , an embodiment of the present invention further discloses a control method 200 for the heat exchange system. Figure 5 A flow chart of a control method 200 is shown.

[0062] Any one or more steps in method 200 may be performed by, for example Figure 1 、 Figure 3 Any one of the devices in the heat exchange system 100, Figure 2 or Figure 4 control unit 160, Figure 9 The electronic device 300 is implemented. Figure 5 As shown, the control method 200 for the heat exchange system can be specifically described as follows.

[0063] In S201 , the set temperature of the water after heat exchange is obtained.

[0064] The set temperature of the water exiting the heat exchanger can be set based on the actual conditions of the production line. For example, when the heat-exchanged water is used for gypsum slurry mixing, the set temperature can be anywhere between 50°C and 60°C. The set temperature can be obtained from the heat exchange system's control unit (e.g., a programmable logic controller (PLC)), a temperature sensing unit, and / or any storage device storing sensing data.

[0065] In S202 , the detected temperature of the water after heat exchange is obtained.

[0066] The detected temperature of the water subjected to the heat exchange process may be acquired from the temperature sensing unit 150 .

[0067] In S203 , the air intake volume of the fan is controlled based on the difference between the set temperature of the heat-exchanged water and the detected temperature of the heat-exchanged water.

[0068] At the beginning of the heat exchange process, the detected water temperature is lower than the set temperature, and the fan motor speed is increased to increase the air flow. As the heat exchange process progresses, the detected water temperature approaches or exceeds the set temperature, and the fan motor speed is reduced to reduce the air flow.

[0069] Controlling the air intake volume of the fan herein may refer to the control unit 160 or any other device in the heat exchange system 100 sending an instruction to adjust the motor speed of the fan.

[0070] The control method for a heat exchange system according to the present invention utilizes high-temperature flue gas to heat ambient-temperature water, thereby recovering the heat from the high-temperature flue gas. Furthermore, the fan airflow is adjusted based on the difference between the hot water temperature after heat exchange and the set water temperature, enabling real-time adjustments based on feedback.

[0071] In some embodiments, a PID algorithm may be used to calculate the difference between the detected water temperature and the set water temperature, and a frequency converter may be used to adjust the motor speed of the fan to achieve precise regulation.

[0072] In some embodiments, before the flue gas enters the heat exchanger, whether to turn on the fan can be determined by detecting the temperature of the flue gas. Figure 6 FIG. 2 is a flow chart of a fan control method 210 according to an embodiment of the present invention. Figure 6 As shown, the fan control method 210 can be specifically described as follows.

[0073] In S211 , the set temperature of the flue gas is obtained.

[0074] The set temperature of the flue gas may be obtained from a control unit of the heat exchange system, a temperature sensing unit, and / or any storage device storing sensing data.

[0075] In S212, the detected temperature of the flue gas is obtained.

[0076] The flue gas temperature can be detected by a third temperature sensing unit provided in the main duct 10 or the induced draft duct 110 .

[0077] In S213 , it is determined whether the detected temperature of the flue gas is greater than or equal to the set temperature of the flue gas.

[0078] If the detected flue gas temperature is greater than or equal to the set flue gas temperature, the process directly proceeds to step S214; otherwise, the process returns to the previous step. In the initial stage of operation of the dryer 11, the detected flue gas temperature will be lower than the set temperature. As the dryer 11 operates, the flue gas temperature will gradually increase to approach or exceed the set temperature.

[0079] In S214, when the detected temperature of the flue gas is greater than or equal to the set temperature of the flue gas, the fan is turned on. When the temperature of the flue gas entering the fan reaches the set temperature, it indicates that the fan can be started.

[0080] In some embodiments, the air inlet speed of the fan is controlled based on the difference between the set temperature and the detected temperature, and when the detected temperature reaches the set temperature, the water in the water tank and the heat exchanger can be circulated by a water pump to equalize the water temperature in the water tank. Figure 7 FIG. 2 is a flow chart of a water pump control method 220 according to an embodiment of the present invention. Figure 7 As shown, the water pump control method 220 can be specifically described as follows.

[0081] In S221 , when the detected temperature of the heat-exchanged water is greater than or equal to the set temperature of the heat-exchanged water, the water pump and the valve between the water pump and the water tank are opened.

[0082] When the hot water temperature coming out of the heat exchanger detected by the sensing unit 150 reaches the set temperature, the water pump and the valve between the water pump and the water tank outlet 125 can be opened to allow the water in the water tank and the water in the heat exchanger to circulate.

[0083] In S222 , the detected temperature of the second area is acquired.

[0084] The water temperature in the second zone II of the water tank can be detected by the temperature sensing unit 151. Because the upper portions of the first and second zones I and II are isolated, water can flow only through the interconnected bottom portions. Hot water from the heat exchanger first enters the first zone I of the water tank, then flows through the bottom of the tank into the second zone II. When the temperature in the second zone II reaches a preset temperature, it indicates that the minimum temperature in the water tank has reached that preset temperature.

[0085] In S223 , the water inlet flow rate of the water pump is adjusted based on the difference between the detected temperature of the second area and the set temperature of the heat-exchanged water.

[0086] For example, when the water temperature of the detected second area II is lower than the set temperature, the water inlet from the water outlet 125 can be increased so that the water in the water tank enters the heat exchanger circulation faster. When the water temperature of the detected second area II is higher than the set temperature, the water inlet from the water outlet 125 can be reduced or even shut off so that the water in the water tank can be maintained near the set temperature. In some examples, the set temperature here may refer to the water temperature detected by the temperature sensing unit 150. After the heat exchanger has been running for a period of time, the water temperature detected by the temperature sensing unit 150 is close to or equal to the set temperature. In some examples, the difference between the detected water temperature and the set water temperature can be calculated by a PID algorithm, and the motor speed of the water pump can be adjusted by a frequency converter to achieve precise adjustment. The error of the water temperature in the water tank after the water pump circulation can be within ±0.5°C.

[0087] In some embodiments, the initial state of the water tank is empty, that is, the hot water from the heat exchanger enters the empty water tank. In some other embodiments, the initial state of the water tank is not empty, that is, the water tank can be partially filled with water from municipal water. Figure 8 FIG. 2 is a flow chart showing a water level control method 230 for a water tank according to an embodiment of the present invention. Figure 8 As shown, the water level control method 230 of the water tank can be specifically described as follows.

[0088] In S231 , the third valve is opened.

[0089] The third valve controls the water that enters the water tank from an external water source rather than the heat exchanger. When the water tank is empty, the third valve is opened to allow water to enter from the external water source.

[0090] In S232 , the set liquid level of the water tank is obtained.

[0091] The set liquid level of the water tank may be obtained from a control unit of the heat exchange system, a liquid level sensing unit, and / or any storage device storing sensing data.

[0092] In S233, the detected liquid level of the water tank is obtained.

[0093] The liquid level in the water tank can be obtained by a liquid level sensing unit. In some examples, the liquid level sensing unit can be any one of an optical liquid level sensor, a capacitive liquid level sensor, a conductive liquid level sensor, a vibration liquid level sensor, an ultrasonic liquid level sensor, and a microwave liquid level sensor.

[0094] In S234 , it is determined whether the detected liquid level of the water tank is higher than or equal to the set liquid level of the water tank.

[0095] The data of the set liquid level and the detected liquid level can be compared to determine whether the detected liquid level has reached the set liquid level requirement. If so, the process proceeds to S235; otherwise, the process returns to the previous step.

[0096] In S235 , when the detected liquid level of the water tank is higher than or equal to the set liquid level of the water tank, the third valve is closed.

[0097] If the detected liquid level reaches the set liquid level requirement, that is, the water level in the water tank reaches the requirement, the external water source entering the water tank can be closed.

[0098] The water level control method 230 of the water tank can ensure that there is a certain amount of water in the water tank in the heat exchange system, and can play a buffering role when subsequently receiving hot water from the heat exchanger, rather than just serving as a water tank for receiving hot water.

[0099] refer to Figure 9 , Figure 9 A schematic diagram of an electronic device 300 according to an embodiment of the present invention is shown. The electronic device 300 includes a processor (e.g., a central processing unit (CPU)) 301 and a memory 302 coupled to the processor 301. The memory 302 is used to store computer-executable instructions, which, when executed, cause the processor 301 to perform the method in the above embodiment. The processor 301 and the memory 302 are connected to each other via a bus, and an input / output (I / O) interface is also connected to the bus. The electronic device 300 may also include multiple components (not shown) connected to the I / O interface, including but not limited to: an input unit, such as a keyboard, a mouse, etc.; an output unit, such as various types of displays, speakers, etc.; a storage unit, such as a magnetic disk, an optical disk, etc.; and a communication unit, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit allows the electronic device 300 to exchange information / data with other devices via a computer network such as the Internet and / or various telecommunication networks.

[0100] Now back Figure 1 The heat exchange system 100. The control unit 160 of the heat exchange system 100 may include a processor and a memory, and the processor and the memory may be, for example, Figure 9 The heat exchange system 100 may further include at least one controller (such as a PLC).

[0101] The controller can be an independent hardware structure or a module integrated into other hardware. Alternatively, the controller can be a software module, for example, including a set of control instructions. In some examples, the controller can be integrated with the processor 301, or can be separate from the processor 301 and can communicate with each other (for example, via a communication link). For example, the controller can provide various acquired information to the processor 301. In some examples, the controller can be the processor 301.

[0102] In some examples, the system 100 may also include a display device (not shown in the figure). The display device is also communicatively coupled to the control unit 160, and may be, for example, a touch screen, a liquid crystal display, or the like. Although in this example, the display device is shown as being part of the system 100, in other examples, the display device may also be a display device independent of the system 100. In some examples, the display device may also be a display screen of an electronic device such as a smart phone or a tablet computer, and so on. The number of display devices may be one or more. For example, the display device may include a main screen and a touch screen, the main screen being mainly used to display a virtual production site, and the touch screen being mainly used for human-computer interaction. The display device has a display interface, which includes multiple display areas, each display area corresponding to at least one device.

[0103] In addition, alternatively, the above method can be implemented by a computer-readable storage medium. The computer-readable storage medium is loaded with computer-readable program instructions for executing the various embodiments of the present utility model. The computer-readable storage medium can be a tangible device that can hold and store instructions used by an instruction execution device. The computer-readable storage medium can be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. More specific examples (non-exhaustive) of computer-readable storage media include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, for example, a punch card or a protruding structure in a groove on which instructions are stored, and any suitable combination thereof. The computer-readable storage medium used herein is not to be construed as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., light pulses through a fiber optic cable), or an electrical signal transmitted through wires.

[0104] Therefore, in another embodiment, the present invention provides a computer-readable storage medium having computer-executable instructions stored thereon, and the computer-executable instructions are used to execute the methods in various embodiments of the present invention.

[0105] The present invention also provides a computer program product, which is tangibly stored on a computer-readable storage medium and includes computer-executable instructions. When the computer-executable instructions are executed, at least one processor is enabled to perform the methods in various embodiments of the present invention.

[0106] In general, the various example embodiments of the present invention may be implemented in hardware or dedicated circuitry, software, firmware, logic, or any combination thereof. Certain aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. When various aspects of the embodiments of the present invention are illustrated or described as block diagrams, flow charts, or using some other graphical representation, it will be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented, as non-limiting examples, in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or a controller or other computing device, or some combination thereof.

[0107] Computer-readable program instructions or computer program products for executing the various embodiments of the present invention can also be stored in the cloud. When needed, users can access the computer-readable program instructions for executing an embodiment of the present invention stored in the cloud through mobile Internet, fixed network or other networks, thereby implementing the technical solutions disclosed in accordance with the various embodiments of the present invention.

[0108] Although embodiments of the present invention have been described with reference to several specific embodiments, it should be understood that the embodiments of the present invention are not limited to the specific embodiments disclosed. The embodiments of the present invention are intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A heat exchange system, characterized in that: It includes: a fan, a heat exchanger, a first temperature sensing unit, a control unit and a water tank, wherein: The fan is connected to the heat exchanger, and the fan is configured to introduce the flue gas into the heat exchanger; The heat exchanger includes an air inlet, an air outlet, a first water inlet, a water pipe, and a first water outlet. The air inlet is located at the bottom of the heat exchanger, and the air outlet is located at the top of the heat exchanger. The first water inlet is configured to be connected to an external water supply pipe and to introduce an external water source into the water pipe. The water pipe is configured to perform heat exchange between the external water source and the flue gas. The exterior of the water pipe is configured to contact the flue gas, and the interior of the water pipe is configured to accommodate the external water source. The first water outlet is configured to discharge the water that has undergone heat exchange, and the air outlet is configured to discharge the exhaust gas that has undergone heat exchange. The first temperature sensing unit is configured to detect the temperature of the heat-exchanged water; and The control unit is connected to the first temperature sensing unit and the fan, and the control unit is configured to adjust the air intake volume of the fan according to the temperature of the water that has undergone heat exchange; and The water tank comprises: a partition, the partition dividing the water tank into a first area and a second area, the bottom of the first area being connected to the bottom of the second area; and A second water inlet and a second water outlet, the second water inlet is connected to the first water outlet, the second water inlet is located above the first area, the second water outlet is located below the first area, and the second water outlet is configured to supply water to a downstream production line.

2. The heat exchange system according to claim 1, characterized in that The system further includes a first frequency converter, wherein the first frequency converter is communicatively coupled to the control unit and the fan.

3. The heat exchange system according to claim 1, characterized in that It also includes a water pump and a second temperature sensing unit, and the water tank also includes a third water outlet, wherein, The third water outlet is located below the second area, the water inlet of the water pump is connected to the third water outlet and the external water supply pipe, and the water outlet of the water pump is connected to the first water inlet; The second temperature sensing unit is configured to detect a water temperature of the second area; and The control unit is further configured to adjust the water intake of the water pump according to the water temperature of the second area.

4. The heat exchange system according to claim 3, characterized in that A second frequency converter is also included, and the second frequency converter is communicatively coupled to the control unit and the water pump.

5. The heat exchange system according to claim 1, characterized in that Also includes, an induced air duct connected to the fan, the induced air duct being configured to receive the flue gas from an external duct; as well as an exhaust duct connected to the air outlet, the exhaust duct being configured to discharge the exhaust gas to the external duct; Wherein, a first valve is provided on the induced air duct, and a second valve is provided on the exhaust air duct. The first valve is configured to adjust the flow rate of the flue gas, and the second valve is configured to adjust the flow rate of the exhaust gas.

6. The heat exchange system according to claim 1, characterized in that The water tank also includes a third water inlet, and the system also includes a third valve and a liquid level sensing unit. The third water inlet is connected to the third valve, and the third valve is an automatic opening control valve. The third valve is configured to be connected to the external water supply pipe and control the water inlet of the external water supply pipe. The liquid level sensing unit is configured to detect the liquid level of the water tank.

7. The heat exchange system according to claim 1, characterized in that The system further comprises a third temperature sensing unit configured to detect the temperature of the flue gas. The control unit is further configured to adjust the opening state of the fan according to the temperature of the flue gas.

8. The heat exchange system according to claim 7, characterized in that: The third temperature sensing unit is located in the main duct or the induced air duct.

9. The heat exchange system according to claim 1, characterized in that The water pipe includes a plurality of U-shaped pipe units, which are sequentially connected to form a channel, wherein each U-shaped pipe unit includes one or more fins.

10. The heat exchange system according to claim 1, characterized in that The heat exchanger further includes a water extraction pipe located near the water pipe and configured to collect water generated by condensation of the flue gas.

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