Waste heat utilization heating system

Abstract

The utility model relates to a waste heat recovery technical field especially a waste heat utilization heating system. Waste heat utilization heating system includes two heat exchange passages: first heat exchange passage heats 30 DEG C return water to 85 DEG C medium temperature water supply gradually; second heat exchange passage is heated to 55 DEG C low temperature water supply; Waste heat pipe network is divided into three branches: 80 DEG C medium temperature waste heat is directly exchanged through plate heat exchanger; 50 DEG C waste heat is cooled by two stage heat pump cascade; 40 DEG C low temperature waste heat is treated by plate heat exchanger and four stage heat pump, and finally waste heat is reduced to 32 DEG C or 33 DEG C and is discharged into cooling tower. The system improves energy efficiency through temperature accurate matching and small temperature difference multistage heat extraction, realizes high waste heat recovery rate, has the advantages of double temperature water supply adaptation different heating demand, modular heat pump load regulation etc. simultaneously, and is applicable to industrial waste heat recovery and regional heating scene.

Description

Technical Field

[0001] This utility model relates to the field of waste heat recovery technology, and in particular to a waste heat utilization heating system. Background Technology

[0002] Waste heat recovery heating systems are comprehensive energy utilization systems that recover waste heat generated in industrial production or other processes that would otherwise be discarded or emitted, and convert it into heat energy that can be used for heating to meet the winter heating needs of buildings or specific areas.

[0003] Currently, some waste heat recovery systems utilize waste heat within a specific temperature range, failing to comprehensively and effectively utilize waste heat at different temperatures. Furthermore, they may lack the capacity to adequately raise the temperature of return heating water, unable to effectively heat water from 30°C to higher temperatures to meet varying heating needs. Other systems do not fully recover heat from waste heat, resulting in some waste; they can only provide heating water at a single temperature, unable to flexibly provide different temperatures based on the heating needs of different areas or at different times. Existing waste heat recovery systems lack effective integration and collaborative mechanisms between various heat exchange and heat pump devices, leading to low overall system efficiency. Utility Model Content

[0004] The technical problem to be solved by this utility model is: in order to solve the problems existing in the prior art in the background art, a waste heat utilization heating system is provided, which realizes energy cascade utilization through multi-stage heat exchange and heat pump collaboration.

[0005] The technical solution adopted by this utility model to solve its technical problem is: a waste heat utilization heating system, including: a first plate heat exchanger, a second plate heat exchanger, a first centrifugal heat pump, a second centrifugal heat pump, a third centrifugal heat pump, a fourth centrifugal heat pump, a fifth centrifugal heat pump, a sixth centrifugal heat pump, a heating water return pipe, a medium-temperature heating water supply pipe, a low-temperature heating water supply pipe, and a waste heat water supply network; The heating water return pipe is connected to the first heat exchange passage and the second heat exchange passage respectively. The first heat exchange passage flows through the first plate heat exchanger, the first centrifugal heat pump and the second centrifugal heat pump in sequence. After heat exchange and temperature increase in each stage, it is connected to the medium-temperature heating water supply pipe. The second heat exchange passage flows through the second plate heat exchanger, the third centrifugal heat pump, the fourth centrifugal heat pump, the fifth centrifugal heat pump and the sixth centrifugal heat pump in sequence. After heat exchange and temperature increase in each stage, it is connected to the low-temperature heating water supply pipe. The waste heat water supply network includes a first waste heat branch, a second waste heat branch, and a third waste heat branch. The first medium-temperature waste water output from the first waste heat branch is heat-exchanged by a first plate heat exchanger and then output as low-temperature water connected to a backup plate heat exchanger. The second medium-temperature waste water output from the second waste heat branch is heat-exchanged by a second centrifugal heat pump and a first centrifugal heat pump in sequence and then output as low-temperature water connected to a backup plate heat exchanger. The low-temperature waste water output from the third waste heat branch is cooled by heat exchanged by a second plate heat exchanger and a third, fourth, fifth, and sixth centrifugal heat pump before entering the cooling tower.

[0006] By setting up first and second plate heat exchangers and multiple centrifugal heat pumps, two independent heat exchange pathways are formed. The return heating water enters these two pathways respectively, undergoing step-by-step heat exchange and temperature increase in different heat exchange devices before finally connecting to medium- and low-temperature heating water supply pipes. This achieves staged heating of the heating water to meet the temperature requirements of different scenarios. Simultaneously, the waste heat supply network is divided into three branches, each introducing waste water at different temperatures into corresponding heat exchange devices for heat exchange, fully utilizing waste heat resources at various temperatures and improving overall energy efficiency.

[0007] According to one embodiment of the present invention, the input water temperature of the first waste heat branch is 80°C and the output water temperature is 35°C.

[0008] The first medium-temperature waste water with an input temperature of 80℃ is output as low-temperature water at 35℃ after heat exchange in the first plate heat exchanger. This clearly defined water temperature change setting makes the heat exchange process predictable and controllable: on the one hand, the 80℃ waste water has high thermal energy, which can provide sufficient heat for the heating water return through heat exchange; on the other hand, the output 35℃ low-temperature water is connected to the backup plate heat exchanger and can be used for other processes or equipment that require low-temperature heat sources, realizing further cascade utilization of waste heat and improving the energy utilization efficiency of the entire system.

[0009] According to one embodiment of the present invention, the input water temperature of the second waste heat branch is 50°C and the output water temperature is 39.4°C.

[0010] The second medium-temperature waste water, with an input temperature of 50℃, passes through a second centrifugal heat pump and then a first centrifugal heat pump for heat exchange, outputting low-temperature water at 39.4℃. The 50℃ waste water temperature is relatively moderate, and the heat exchange through the two-stage centrifugal heat pumps effectively extracts its heat for heating the return water from the heating system. The output 39.4℃ low-temperature water is also connected to a backup heat exchanger to provide a heat source for other low-temperature heating applications, further expanding the application range of waste heat and reducing energy waste.

[0011] According to one embodiment of the present invention, the input water temperature of the third waste heat branch is 40°C and the output water temperature is 32°C.

[0012] Low-temperature waste water with an input temperature of 40℃ is cooled by heat exchange through a second plate heat exchanger and multiple centrifugal heat pumps before entering the cooling tower. Although the waste water is at a low temperature of 40℃, through a reasonable combination of heat exchange equipment, some of its heat can still be transferred to the heating water return. After heat exchange, the water temperature drops to 32℃ before entering the cooling tower. This not only realizes the recovery and utilization of waste heat, but also ensures that the cooling tower can operate with water at a lower temperature, improving the operating efficiency of the cooling tower, and reducing the impact of water temperature on the environment.

[0013] According to one embodiment of the present invention, the input water temperature of the first heat exchange passage is 30°C and the output water temperature is 85°C.

[0014] The heating water return water with an input temperature of 30℃ is heated through a series of heat exchangers, including the first plate heat exchanger, the first centrifugal heat pump, and the second centrifugal heat pump, until the output water temperature reaches 85℃. This medium-temperature heating water can meet the heating needs of areas or equipment with high heating temperature requirements. Through the action of multi-stage heat exchange equipment, the heating water temperature is gradually increased, ensuring the stability and efficiency of the heat exchange process.

[0015] According to one embodiment of the present invention, the input water temperature of the second heat exchange passage is 30°C and the output water temperature is 55°C.

[0016] Similarly, the return water, which is 30°C, flows through the second plate heat exchanger and multiple centrifugal heat pumps in sequence, and the output water temperature is 55°C. The 55°C heating water is suitable for areas with relatively low heating temperature requirements. This tiered heating method can rationally allocate heat according to the needs of different users, avoid excessive energy consumption, and improve the targeted use of energy.

[0017] According to one embodiment of the present invention, in the first heat exchange passage, the temperature rise of the first centrifugal heat pump and the second centrifugal heat pump is 5.3°C.

[0018] The temperature rise of the first centrifugal heat pump and the second centrifugal heat pump in the first heat exchange path is limited to 5.3℃. This precise temperature rise setting helps optimize the operating parameters of the heat pumps and ensures that the heat pumps work under optimal conditions. By controlling the temperature rise, the heat pumps can maintain a high energy efficiency ratio during the extraction of waste heat and heating of heating water, reducing energy consumption and improving the heat exchange efficiency of the entire heat exchange path. At the same time, a stable temperature rise is also conducive to the stable operation of the system and reduces the damage to the equipment caused by temperature fluctuations.

[0019] According to one embodiment of the present invention, in the second heat exchange path, the temperature rise of each centrifugal heat pump from the third to the sixth centrifugal heat pump is 4.75°C.

[0020] The temperature rise of each centrifugal heat pump in the second heat exchange path, from the third to the sixth centrifugal heat pump, is limited to 4.75℃. Similar to the first heat exchange path, this step-by-step temperature rise setting is to optimize the coordinated operation of multiple centrifugal heat pumps. Through reasonable temperature rise distribution, each heat pump can fully utilize its heat exchange capacity, achieving a gradual and stable temperature rise in the heating water return water. At the same time, precise temperature rise control helps improve the reliability and stability of the entire heat exchange path, ensuring that low-temperature heating water can be supplied according to the expected temperature requirements.

[0021] According to one embodiment of the present invention, in the second waste heat branch, the temperature drop of the second centrifugal heat pump and the first centrifugal heat pump is 5.3°C.

[0022] The temperature drop of the second centrifugal heat pump and the first centrifugal heat pump in the second waste heat branch is limited to 5.3℃. In the second waste heat branch, by controlling the temperature drop of the centrifugal heat pump, the heat in the 50℃ waste water can be effectively extracted and transferred to the heating water return. The precise temperature drop setting helps to improve the heat exchange efficiency of the heat pump and make full use of the waste heat. At the same time, the stable temperature drop also helps to ensure the stability of the heat exchange process and avoid adverse effects on the equipment and system due to excessive temperature changes.

[0023] According to one embodiment of the present invention, in the third waste heat branch, the temperature drop of the third centrifugal heat pump, the fourth centrifugal heat pump, the fifth centrifugal heat pump, and the sixth centrifugal heat pump is all 5°C.

[0024] The temperature drop of the third, fourth, fifth, and sixth centrifugal heat pumps in the third waste heat branch is limited to 5℃. For the low-temperature waste water at 40℃, the heat can be transferred to the heating water return water through heat exchange via the separate temperature drops of multiple centrifugal heat pumps. The reasonable temperature drop setting can ensure that each heat pump can operate under suitable conditions, improving the efficiency of waste heat recovery. At the same time, the waste water temperature drops to 33℃ before entering the cooling tower, providing a suitable inlet water temperature for the cooling tower and ensuring the normal operation of the cooling system.

[0025] The beneficial effects of this utility model are: (1) The system can make full use of waste heat resources at different temperatures. Through reasonable heat exchange equipment combination and precise water temperature control, the heat in the waste heat can be extracted to the maximum extent and converted into heat energy that can be used for heating. At the same time, the low temperature water after heat exchange is reasonably utilized, realizing the cascade utilization of waste heat and improving the comprehensive utilization efficiency of energy. (2) By setting up two independent heat exchange channels, the heating water return water is heated to 85℃ and 55℃ respectively, which meets the diverse needs of different users for heating temperature; medium temperature heating water can be used in industrial or special process scenarios with high heating temperature requirements, while low temperature heating water is suitable for heating ordinary civil buildings, avoiding energy waste and improving the targeting of energy utilization.

[0026] (3) Precise control of the step-by-step temperature rise and fall in each heat exchanger ensures the stability of the system during operation. Stable temperature changes help reduce the damage to equipment caused by temperature fluctuations, extend the service life of the equipment, and reduce the maintenance cost of the system. (4) The system reduces dependence on traditional energy sources, lowers energy consumption and operating costs, and reduces thermal pollution caused by direct emissions of waste heat by efficiently recovering and utilizing waste heat. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Figure 1 This is a schematic diagram of the structure of this utility model.

[0029] In the diagram: 1. First plate heat exchanger; 2. Second plate heat exchanger; 3. First centrifugal heat pump; 4. Second centrifugal heat pump; 5. Third centrifugal heat pump; 6. Fourth centrifugal heat pump; 7. Fifth centrifugal heat pump; 8. Sixth centrifugal heat pump; 9. Heating water return pipe; 10. Medium-temperature heating water supply pipe; 11. Low-temperature heating water supply pipe; 12. 80℃ waste hot water supply pipe; 13. 50℃ waste hot water supply pipe; 14. 40℃ waste hot water supply pipe; 15. Protective plate heat exchanger; 16. Cooling tower. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0031] like Figure 1As shown, a waste heat utilization heating system includes a first plate heat exchanger 1, a second plate heat exchanger 2, a first centrifugal heat pump 3, a second centrifugal heat pump 4, a third centrifugal heat pump 5, a fourth centrifugal heat pump 6, a fifth centrifugal heat pump 7, a sixth centrifugal heat pump 8, a heating water return pipe 9, a medium-temperature heating water supply pipe 10, a low-temperature heating water supply pipe 11, and a waste heat supply network. The heating water return pipe 9 connects to the first heat exchange path and the second heat exchange path. The first heat exchange path flows sequentially through the first plate heat exchanger 1, the first centrifugal heat pump 3, and the second centrifugal heat pump 4, and after staged heat exchange and temperature increase, it connects to the medium-temperature heating water supply pipe 10. The second heat exchange path flows sequentially through the second plate heat exchanger 2, the third centrifugal heat pump 5, the fourth centrifugal heat pump 6, the fifth centrifugal heat pump 7, the sixth centrifugal heat pump 8, the second plate heat exchanger 9, the third centrifugal heat pump 10, the fifth centrifugal heat pump 11, the sixth centrifugal heat pump 11, and the waste heat supply network. Heat pump 6, centrifugal heat pump 7, and centrifugal heat pump 8 are connected to the low-temperature heating water supply pipe 11 after being heated through heat exchange in stages. The waste heat supply network includes the first waste heat branch, the second waste heat branch, and the third waste heat branch. The first medium-temperature waste water output from the first waste heat branch is heated by the first plate heat exchanger 1 and then output as low-temperature water connected to the protection plate heat exchanger 15. The second medium-temperature waste water output from the second waste heat branch is heated by the second centrifugal heat pump 4 and the first centrifugal heat pump 3 in sequence and then output as low-temperature water connected to the protection plate heat exchanger 15. The low-temperature waste water output from the third waste heat branch is cooled by the second plate heat exchanger 2 and the third centrifugal heat pump 5, the fourth centrifugal heat pump 6, the fifth centrifugal heat pump 7, and the sixth centrifugal heat pump 8 before entering the cooling tower 16.

[0032] Specifically, the first waste heat branch is connected to an 80°C waste hot water supply pipe 12. 80°C water is input, passes through the first plate heat exchanger 1, and outputs water at 35°C, which is then connected to the protective plate heat exchanger 15. The second waste heat branch is connected to a 50°C waste hot water supply pipe 13. 50°C water is input, passes through the second centrifugal heat pump 4, outputs water at 44.7°C, and then passes through the first centrifugal heat pump 3, outputting water at 39.4°C, which is then connected to the protective plate heat exchanger 15. Thus, in the second waste heat branch, the temperature drop between the second centrifugal heat pump 4 and the first centrifugal heat pump 3 is 5.3°C. The third waste heat branch is connected to the 40℃ waste hot water supply pipe 14. Water at 38℃ is input, and after heat exchange in the second plate heat exchanger 2, the output water temperature is 32℃ before entering the cooling tower 16. At the same time, the 38℃ water is cooled to 33℃ after heat exchange in the third centrifugal heat pump 5, the fourth centrifugal heat pump 6, the fifth centrifugal heat pump 7, and the sixth centrifugal heat pump 8, and then also enters the cooling tower 16. Thus, in the third waste heat branch, the temperature drop of the third centrifugal heat pump 5 to the sixth centrifugal heat pump 8 is 5℃.

[0033] The first heat exchange path connects to the heating water return pipe 9. Water at 30°C is heated to 74.4°C by the first plate heat exchanger 1, then to 79.7°C by the first centrifugal heat pump 3, and finally to 85°C by the second centrifugal heat pump 4 before being connected to the medium-temperature heating water supply pipe 10. Thus, in the first heat exchange path, the temperature rise of the first centrifugal heat pump 3 and the second centrifugal heat pump 4 is 5.3°C. In the second heat exchange path, the 30℃ water output from the heating water return pipe 9 is heated to 36℃ by the second plate heat exchanger 2, then heated to 40.75℃ by the third centrifugal heat pump 5, then heated to 45.5℃ by the fourth centrifugal heat pump 6, then heated to 50.25℃ by the fifth centrifugal heat pump 7, and finally heated to 55℃ by the sixth centrifugal heat pump 8 before entering the low-temperature heating water supply pipe 11. Thus, in the second heat exchange path, the temperature rise of each stage from the third centrifugal heat pump 5 to the sixth centrifugal heat pump 8 is 4.75℃.

[0034] The waste heat utilization heating system in this embodiment is divided into three independent branches based on the temperature difference of the waste heat source, each matching different heat demands. Waste heat at 80℃ is directly supplied via plate heat exchangers, while waste heat at 50℃ is progressively heated by heat pumps, achieving precise energy level matching for medium-temperature heating and low-temperature heating. The third waste heat branch uses a composite processing mode of one plate heat exchanger and four heat pumps to handle 40℃ low-temperature waste heat, raising the traditionally unusable low-grade heat to a heating temperature of 55℃ through multi-stage heat pumps. The final outlet temperature of the waste heat drops to 32℃ or 33℃, close to the ambient temperature. Six centrifugal heat pumps form a two-stage heating chain, with each stage temperature rise controlled within the range of 4.75-5.3℃. This multi-stage heating strategy with small temperature differences reduces compressor power consumption compared to a single-stage large temperature rise. Separate 85℃ and 55℃ water supply pipelines are provided to avoid energy quality waste caused by supplying water at a single temperature.

[0035] Furthermore, if one waste heat branch fails, the remaining branches can still maintain basic heating through the backup power supply. Compared to traditional electric boiler heating, this system utilizes waste heat as the primary heat source, with only the heat pump consuming electricity. Moreover, the centrifugal heat pump adopts a modular design, with the temperature rise of a single unit controlled at around 5°C, reducing the power requirement of a single unit and allowing for load adjustment by increasing or decreasing the number of operating units, thus reducing costs.

[0036] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A waste heat utilization heating system, characterized in that, include: First plate heat exchanger (1), second plate heat exchanger (2), first centrifugal heat pump (3), second centrifugal heat pump (4), third centrifugal heat pump (5), fourth centrifugal heat pump (6), fifth centrifugal heat pump (7), sixth centrifugal heat pump (8), heating water return pipe (9), medium temperature heating water supply pipe (10), low temperature heating water supply pipe (11) and waste heat water supply network; The heating water return pipe (9) is connected to the first heat exchange passage and the second heat exchange passage respectively. The first heat exchange passage flows through the first plate heat exchanger (1), the first centrifugal heat pump (3) and the second centrifugal heat pump (4) in sequence. After the heat exchange is raised step by step, it is connected to the medium-temperature heating water supply pipe (10). The second heat exchange passage flows through the second plate heat exchanger (2), the third centrifugal heat pump (5), the fourth centrifugal heat pump (6), the fifth centrifugal heat pump (7) and the sixth centrifugal heat pump (8) in sequence. After the heat exchange is raised step by step, it is connected to the low-temperature heating water supply pipe (11). The waste heat water supply network includes a first waste heat branch, a second waste heat branch and a third waste heat branch. The first medium-temperature waste water output from the first waste heat branch is heat-exchanged by the first plate heat exchanger (1) and then output as low-temperature water connected to the protection plate heat exchanger (15). The second medium-temperature waste water output from the second waste heat branch is heat-exchanged by the second centrifugal heat pump (4) and the first centrifugal heat pump (3) in sequence and then output as low-temperature water connected to the protection plate heat exchanger (15). The low-temperature waste water output from the third waste heat branch is heat-exchanged and cooled by the second plate heat exchanger (2) and the third centrifugal heat pump (5), the fourth centrifugal heat pump (6), the fifth centrifugal heat pump (7) and the sixth centrifugal heat pump (8) and then enters the cooling tower (16).

2. The waste heat utilization heating system according to claim 1, characterized in that: The input water temperature of the first waste heat branch is 80℃, and the output water temperature is 35℃.

3. The waste heat utilization heating system according to claim 1, characterized in that: The input water temperature of the second waste heat branch is 50℃, and the output water temperature is 39.4℃.

4. The waste heat utilization heating system according to claim 1, characterized in that: The input water temperature of the third waste heat branch is 40℃, and the output water temperature is 32℃.

5. The waste heat utilization heating system according to claim 1, characterized in that: The input water temperature of the first heat exchange passage is 30°C, and the output water temperature is 85°C.

6. The waste heat utilization heating system according to claim 1, characterized in that: The input water temperature of the second heat exchange passage is 30°C, and the output water temperature is 55°C.

7. The waste heat utilization heating system according to claim 1, characterized in that: In the first heat exchange path, the temperature rise of the first centrifugal heat pump (3) and the second centrifugal heat pump (4) is 5.3℃.

8. The waste heat utilization heating system according to claim 1, characterized in that: In the second heat exchange path, the temperature rise of the third centrifugal heat pump (5) to the sixth centrifugal heat pump (8) is 4.75℃.

9. The system according to claim 1, characterized in that: In the second waste heat branch, the temperature drop of the second centrifugal heat pump (4) and the first centrifugal heat pump (3) is 5.3℃.

10. The system according to claim 1, characterized in that: In the third waste heat branch, the temperature drop of the third centrifugal heat pump (5), the fourth centrifugal heat pump (6), the fifth centrifugal heat pump (7), and the sixth centrifugal heat pump (8) is 5℃.

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