Heat exchange system capable of intelligently switching flow modes

Abstract

The invention provides a heat exchange system capable of intelligently switching flow modes, a heat source flow path comprises a first flow mode and a second flow mode, in the first flow mode, a pipeline valve and a second valve are opened, a first valve and an outlet valve are closed, and in the first flow mode of a heat source, the heat source passes through the pipeline valve to heat a heat exchanger and then passes through the second valve; the water flows out from the tail end of the inlet branch; the second flowing mode of the heat source is that the first valve and the outlet valve are opened, the second valve and the pipeline valve are closed, the pipeline valve heat source passes through the first valve to conduct heat exchanger and then flows into the heat source pipeline through the outlet valve, and the controller controls fluid to flow between the first mode and the second mode according to needs. According to the heat exchange system, the positions of the inlet and the outlet of the tube pass of the shell-and-tube heat exchanger can be changed, so that the temperatures of a heating cold source and a cooling heat source are kept in a certain range and can be selected.

Description

Technical Field

[0001] The present invention relates to a heat exchange system, and more particularly to an intelligent controlled heat source heat exchange system. Background Art

[0002] At present, the heat source of the heat exchange system is divided into various types, and the heat source may include solar energy, boiler hot water or steam, boiler waste heat, etc. Solar energy is an inexhaustible clean energy source with a huge amount of resources. The total amount of solar radiation energy received by the earth's surface every year is 1×10 18 kW·h, which is more than ten thousand times the total annual energy consumption of the world. However, due to the small energy density of solar radiation reaching the earth (about one kilowatt per square meter) and its discontinuity, it brings certain difficulties to large-scale development and utilization. Therefore, in order to widely utilize solar energy, not only technical problems need to be solved, but also it must be economically competitive with conventional energy sources. There are various industrial plants around cities in our country. During the industrial production process, heat source resources are generally present, especially in industries such as metallurgy, chemical industry, petroleum, building materials, glass, and paper. At present, the treatment method of industrial waste heat is to dissipate it into the atmosphere through the heat dissipation system in the plant area. According to statistics, nearly two-thirds of the waste heat has not been effectively utilized, consuming a large amount of energy in the industrial field, and finally most of the energy is discharged in the form of hot water and hot smoke, resulting in energy waste.

[0003] A heat pipe network, also known as a heat pipeline, starts from a boiler room, a direct-fired machine room, a heat supply center, etc., and is a heat supply pipeline leading from a heat source to the heat inlet of a building. Multiple heat supply pipelines form a pipeline network. The design pressure of the heat supply hot water medium is less than or equal to 2.5 MPa, and the design temperature is less than or equal to 200 °C. The design of the following heat pipe networks with a design pressure of the heat supply steam medium less than or equal to 1.6 MPa and a design temperature less than or equal to 350 °C. Currently, when heating, generally each household uses a heat exchanger for heat exchange to carry out heating.

[0004] A shell-and-tube heat exchanger, also known as a tubular heat exchanger, is a shell-and-tube type heat exchanger that uses the wall surface of the tube bundle enclosed in the shell as the heat transfer surface. This type of heat exchanger has a relatively simple structure, reliable operation, can be made of various structural materials (mainly metal materials), and can be used under high temperature and high pressure. It is the most widely used type at present.

[0005] Shell-and-tube heat exchangers are widely used in industries such as chemical engineering, petroleum, refrigeration, nuclear energy, and power. Due to the worldwide energy crisis, in order to reduce energy consumption, the demand for heat exchangers in industrial production is increasing, and the quality requirements for heat exchangers are also getting higher and higher. In recent decades, although compact heat exchangers (such as plate-type, plate-fin type, and welded-plate heat exchangers), heat pipe heat exchangers, direct-contact heat exchangers, etc. have developed rapidly, due to the high reliability and wide adaptability of shell-and-tube heat exchangers, they still dominate in terms of production and usage. According to relevant statistics, the usage of shell-and-tube heat exchangers in industrial installations currently still accounts for about 70% of the total usage of all heat exchangers.

[0006] In the current thermal system of shell-and-tube heat exchangers, there are the following problems: The flow directions at the inlet and outlet of the shell-and-tube heat exchanger cannot be changed. When the shell-and-tube heat exchanger is not in use, there is no fluid passing through, which is likely to breed bacteria, especially for shell-and-tube heat exchangers for domestic water. At the same time, the descaling effect of shell-and-tube heat exchangers is not good, and the dirt in the tube side cannot be removed in time.

[0007] In response to the above problems, the present invention has been improved by adopting a heat source heat exchange system with a new structure, which can solve at least one of the problems of changing the inlet direction of the shell side, ensuring sterilization inside the heat exchanger, and maintaining good descaling. Summary of the Invention

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] An intelligent switching flow mode heat exchange system, the heat source flow path includes a first flow mode and a second flow mode. In the first flow mode, the pipeline valve and the second valve are opened, and the first valve and the outlet valve are closed. The first flow mode of the heat source is that the heat source passes through the pipeline valve into the heat exchanger, then passes through the second valve, and flows out from the end of the inlet branch; the second flow mode of the heat source is that the first valve and the outlet valve are opened, and the second valve and the pipeline valve are closed. The heat source passes through the first valve into the heat exchanger, and then flows into the heat source pipeline through the outlet valve. The controller controls the flow of the fluid between the first mode and the second mode according to needs.

[0010] Preferably, the "needs" can be based on the scaling situation of the tube side of the heat exchanger.

[0011] Preferably, the tube side is descaled regularly. During the descaling stage, the controller controls the fluid to flow between the first mode and the second mode periodically according to needs.

[0012] Preferably, during the above descaling stage, the heat exchanger can still carry out heat exchange between the heat source and the cold source, and the cold source in the shell side can still be heated normally.

[0013] Preferably, the "needs" can be based on the heating temperature of the cold source.

[0014] Preferably, if a high cold source output temperature is required, countercurrent heat exchange in the first mode and the second mode is selected; if a low cold source output temperature is required, concurrent heat exchange in the first mode and the second mode is selected, so that the output temperature of the cold source can be controlled.

[0015] Preferably, a normal shell-and-tube heat exchanger operates in a countercurrent mode and switches between countercurrent and concurrent modes during descaling.

[0016] Preferably, the system includes a heat source pipeline, an inlet branch and an outlet branch connected to the inlet and outlet of the heat source pipeline. A first valve and a second valve are provided on the inlet branch, with the first valve upstream of the second valve. An outlet valve is provided on the outlet branch. A first pipeline is connected between the upstream of the first valve on the inlet branch and the upstream of the outlet valve on the outlet branch, and a pipeline valve is provided on the first pipeline. The system further includes a heat exchanger pipeline with a heat exchanger provided thereon. One end of the heat exchanger pipeline is connected to the inlet branch between the first valve and the second valve, and the other end is connected to the first pipeline between the pipeline valve and the outlet branch. A heat source valve is provided on the heat source pipeline between the inlet branch and the outlet branch.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The controller controls the fluid to flow periodically between the first mode and the second mode as needed, so that the heat source continuously flushes the tubes reciprocally, forming a reciprocating intermittent flow for sufficient descaling.

[0019] 2. The heat exchange system of the present invention can change the inlet and outlet positions of the tube side of the shell-and-tube heat exchanger, so that the temperatures of the heated cold source and the cooled heat source can be maintained within a certain selectable range. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of the heat exchange system of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] The following describes in detail the specific embodiments of the present invention with reference to the accompanying drawings.

[0022] In this article, unless otherwise specified, for formulas, " / " represents division, and "×", "*" represent multiplication.

[0023] Figure 1 Disclosed is an intelligent control heat source heat exchange system. As Figure 1As shown, the system includes a heat source pipeline 1, an inlet branch 2 and an outlet branch 3 connected to the inlet and outlet of the heat source pipeline. A first valve 4 and a second valve 5 are provided on the inlet branch, the first valve 4 is located upstream of the second valve 5, and an outlet valve 6 is provided on the outlet branch 3. A first pipeline 7 is connected between the upstream of the first valve 4 on the inlet branch 3 and the upstream of the outlet valve on the outlet branch 3, and a pipeline valve 8 is provided on the first pipeline 7; the system further includes a heat exchanger pipeline 9, and a heat exchanger 10 is provided on the heat exchanger pipeline. One end of the heat exchanger pipeline 10 is connected to the inlet branch 2 between the first valve and the second valve, and the other end is connected to the first pipeline 7 between the pipeline valve and the outlet branch. A heat source valve 11 is provided on the heat source pipeline between the inlet branch and the outlet branch.

[0024] Preferably, when the heat source needs to be utilized, the controller controls the heat source valve, the outlet valve and the first valve to close, and the pipeline valve, the second valve, the shell side inlet valve and the shell side outlet valve to open. After the heat source is heat-exchanged and cooled through the heat exchanger, it flows out from the end of the inlet branch. As an improvement, the heat source is hot water or steam, and the heat source becomes domestic water after heat exchange.

[0025] Preferably, when the heat source does not need to be utilized, the controller controls the heat source valve, the second valve, the shell side inlet valve and the shell side outlet valve to close, and the outlet valve and the first valve to open. The heat source passes through the heat exchanger without heat exchange and flows to the heat source pipeline through the outlet branch.

[0026] The heat exchange system of the present invention can always keep the tube side filled with the heat source, ensure the high-temperature sterilization effect in the tube side, and improve the quality of domestic water.

[0027] Preferably, the heat exchanger is a shell-and-tube heat exchanger, and the heat source passes through the tube side of the heat exchanger.

[0028] Preferably, a shell side inlet valve 11 and a shell side outlet valve 12 are respectively provided at the shell side inlet and the shell side outlet of the heat exchanger.

[0029] Preferably, the heat source flow path includes a first flow mode and a second flow mode. In the first flow mode, the pipeline valve and the second valve are open, and the first valve and the outlet valve are closed. The first flow mode of the heat source is that the heat source passes through the pipeline valve to the heat exchanger, then passes through the second valve, and flows out from the end of the inlet branch; the second flow mode of the heat source is that the first valve and the outlet valve are open, and the second valve and the pipeline valve are closed. The heat source passes through the first valve to the heat exchanger, and then flows into the heat source pipeline through the outlet valve. The controller controls the fluid to flow between the first mode and the second mode as needed.

[0030] The requirement can be based on the fouling condition of the tube side of the heat exchanger. For example, the tube side is descaled regularly. During the descaling stage, the controller controls the fluid to flow periodically between the first mode and the second mode as needed. Thereby, the heat source continuously reciprocally flushes the tubes, forming a reciprocating intermittent flow, so as to perform sufficient descaling.

[0031] During the above descaling stage, the heat exchanger can still perform heat exchange between the heat source and the cold source, and the cold source in the shell side can still be normally heated. Therefore, compared with the descaling methods of the prior art, the above descaling mode does not affect the normal use of the heat exchanger.

[0032] Preferably, the heat source can come from hot water heated by solar energy, hot water or steam heated by a boiler, or hot water heated by waste heat.

[0033] As an improvement, the requirement can be based on the heating temperature of the cold source. Since there are countercurrent or concurrent heat exchange situations in the first mode and the second mode of the heat source, and the heat exchange effects are different, the output temperature of the cold source is different. Therefore, if a high output temperature of the cold source is required, countercurrent heat exchange in the first mode and the second mode is selected; if a low output temperature of the cold source is required, concurrent heat exchange in the first mode and the second mode is selected, so as to control the output temperature of the cold source.

[0034] As an improvement, a normal shell-and-tube heat exchanger operates in a countercurrent mode. During descaling, it switches between countercurrent and concurrent modes.

[0035] The heat exchanger is arranged vertically, and a plurality of baffle plates are arranged in the shell. The baffle plates are arranged horizontally.

[0036] As an improvement, along the flow direction of the fluid in the tube side, from the tube side inlet to the middle position of the tube side, the spacing of the baffle plates continuously increases. Then from the middle position of the tube side to the tube side outlet, the spacing of the baffle plates continuously decreases. Because during the countercurrent process, the heat exchange amount per unit length between the shell side and the tube side along the fluid flow process is relatively uniform, thus making the overall heat exchange effect the best. However, it is found in experiments and simulations that the heat exchange amount in the middle is significantly greater than that at the tube side inlet and outlet. Therefore, by changing the baffle plate spacing, the heat exchange area between the tube side fluid and the shell side fluid in the baffle plates also changes. Therefore, by compensating for the non-uniformity of the heat exchange amount through the area change, the heat exchange efficiency is further improved.

[0037] As an improvement, along the flow direction of the fluid in the tube side, from the tube side inlet to the middle position of the tube side, the increasing amplitude of the baffle plate spacing continuously increases. Then from the middle position of the tube side to the tube side outlet, the decreasing amplitude of the baffle plate spacing continuously decreases. The above amplitude change can make the heat exchange amount per unit length of the entire fluid movement more uniform, further improving the heat exchange efficiency.

[0038] As an improvement, during heat exchange, part of the fluid enters the heat exchanger and part does not. When the heat exchange system is performing heat exchange, as Figure 1 shown, the shell-side inlet valve 11 and the shell-side outlet valve 12 are opened, a cold source is introduced into the heat exchanger 10, the pipeline valve 8 is opened, the first valve 4 is closed, and the second valve 5 is opened. The heat source in the heat source pipeline 1 flows from the water inlet branch 2 and then enters the pipeline 8. Then, part of the heat source directly flows back to the heat source pipeline 1 through the second branch 3, and the other part is introduced into the heat exchanger 10 through the top port of the heat exchanger 10 for cooling. The cooled heat source flows into the inlet branch 2 and flows out from the outlet of the inlet branch 2 into the water-using equipment. Since the heat source flowing back to the heat source pipeline 1 has not been cooled by the heat exchanger 10, it is not only beneficial to reduce the energy consumption of the heat exchanger 10 and avoid energy waste, but also can avoid the influence of the cooled heat source on the water temperature of the heat source pipeline 1, which is beneficial to maintaining the water temperature of the heat source in the heat source pipeline 1.

[0039] As an improvement, when the heat source heat exchange system stops heat exchange, as Figure 1 shown, the shell-side inlet valve 11 and the shell-side outlet valve 12 are closed, the cold source is no longer introduced into the heat exchanger 10, the pipeline valve 8 is closed, the first valve 4 is opened, and the second valve 5 is closed. The heat source in the heat source pipeline 1 flows from the water inlet branch 1 and then enters the heat exchanger pipeline, then enters the heat exchanger 10 through the bottom port of the heat exchanger 10, and exits from the upper port of the heat exchanger 10 and enters the outlet branch 3. Finally, the heat source drawn from the heat source pipeline 1 flows back into the heat source pipeline 1 again, which can ensure that the heat source in the heat source cooling system is always in a circulating state.

[0040] Although the present invention has been disclosed above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope defined by the claims.

Claims

1. A heat exchange system with intelligent switching of flow patterns. The heat source flow path includes a first flow pattern and a second flow pattern. In the first flow pattern, the pipeline valve and the second valve are open, and the first valve and the outlet valve are closed. The first flow pattern of the heat source is that the heat source passes through the pipeline valve to the heat exchanger, then through the second valve, and flows out from the end of the inlet branch. The second flow pattern of the heat source is that the first valve and the outlet valve are open, and the second valve and the pipeline valve are closed. The heat source passes through the first valve to the heat exchanger, then through the outlet valve and flows into the heat source pipeline. The controller controls the flow of the fluid between the first mode and the second mode as needed.

2. The heat exchange system according to claim 1, wherein The said need can be based on the fouling condition of the tube side of the heat exchanger.

3. The heat exchange system according to claim 2, wherein, The tube side is descaled regularly. During the descaling stage, the controller controls the fluid to flow between the first mode and the second mode periodically as needed.

4. The heat exchange system according to claim 3, characterized in that, During the above descaling stage, the heat exchanger can still carry out heat exchange between the heat source and the cold source, and the cold source in the shell side can still be heated normally.

5. The heat exchange system according to claim 1, wherein The said need can be based on the heating temperature of the cold source.

6. The heat exchange system according to claim 5, characterized in that If a high cold source output temperature is required, countercurrent heat exchange in the first mode and the second mode is selected. If a low cold source output temperature is required, concurrent heat exchange in the first mode and the second mode is selected, so that the output temperature of the cold source can be controlled.

7. The heat exchange system according to claim 1, wherein, As an improvement, a normal shell-and-tube heat exchanger operates in the countercurrent mode and switches between countercurrent and concurrent modes during descaling.

Images