A system and heat balance method for transporting recycled water using an urban heating network

Abstract

The present invention relates to a system and a heat balance method for transporting recycled water by using a city heating network. The system comprises a city heating network, which comprises a city heating network return pipe and a city heating network water supply pipe; a recycled water plant, which is connected to the city heating network return pipe through a water injection pipe; a heat pump, which comprises a heat absorbing side and a heat releasing side, the heat absorbing side is used to absorb the heat of the heating network water entering therein, and the heat releasing side uses the heat absorbed from the heat absorbing side to heat the heating network water entering therein; the water inlet of the heat absorbing side is connected to the city heating network return pipe through a heating network return branch pipe, and the water outlet of the heat absorbing side is connected to a water user through a water pipe; the heat releasing side is connected to the city heating network or a secondary heating network through a water pipe, and releases heat to the city heating network or the secondary heating network; the recycled water is transported by using the city heating network, and there is no need to build a dedicated recycled water transport pipeline, thus saving infrastructure costs and reducing the recycled water output cost; heat loss is avoided by heat recovery using the heat pump, so as to achieve heat balance of the city heating network.

Description

Technical Field

[0001] The present invention relates to the technical field of heating and water supply systems, and in particular to a system and a heat balance method for transporting recycled water using a city heating network. Background Art

[0002] The recycled water from treated urban sewage has the characteristics of stable water quality and quantity, centralized and reliable supply. After purification, urban water becomes high-quality recycled water, which can be used to replenish the urban heating network (urban heating network for short), or used for production water of urban industrial enterprises or other industrial and commercial users. If the treated recycled water is reused, it can fill the huge gap of urban water shortage, alleviate the national water shortage problem, reduce sewage discharge, and achieve the unity of economic and environmental benefits.

[0003] The production of high-quality recycled water usually relies on sewage treatment plants, and recycled water users are often scattered in different places. If a new dedicated recycled water transmission pipeline is used, there are problems such as high infrastructure costs, great difficulty, and long time consumption, which reduces the economic benefits of recycled water utilization. Especially for some old urban areas, due to the complexity of underground pipelines and the lack of reserved pipe space, it is almost impossible to build a new supporting recycled water transmission pipeline. Therefore, the problem of recycled water transportation has become an important factor restricting the development of sewage recycling.

[0004] Northern cities are now fully covered by centralized heating pipe networks, and relying on existing heating pipe networks to transport recycled water is a very economical method. However, during the heating season, there is a large temperature difference between the return water temperature of the heating network (25℃-55℃) and the outlet water temperature of recycled water (about 15℃), which leads to the problem of heat loss of heat source. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a system and heat balance method for transporting recycled water using the urban heating network, which solves the problem of heat loss of heat source when transporting recycled water using the urban heating network, realizes the organic combination of urban heating network operation and recycled water transportation, and improves the economic benefits of recycled water utilization.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A system for transporting recycled water using a city heating network, comprising:

[0008] The urban heating network is used to provide heating for the city; the urban heating network includes an urban heating network return pipe and an urban heating network water supply pipe;

[0009] A recycled water plant, which is connected to the return water pipe of the urban heating network through a water injection pipe and is used to replenish the heating network water in the urban heating network;

[0010] A heat pump, comprising a heat absorbing side and a heat releasing side, wherein the heat absorbing side is used to absorb the heat of the water in the heating network entering the heat pump, and the heat releasing side uses the heat absorbed from the heat absorbing side to heat the water in the heating network entering the heat pump; the water inlet of the heat absorbing side is connected to the water return pipe of the urban heating network through the water return branch pipe of the heating network, and the water outlet of the heat absorbing side is connected to the water user through a water pipe; the heat releasing side is connected to the urban heating network or the secondary heating network through the water pipe, and releases heat to the urban heating network or the secondary heating network;

[0011] The urban heating network is connected to at least one of the heat pumps.

[0012] Preferably, the water inlet on the heat release side is connected to the city heating network return pipe through the heat pump inlet return pipeline, and the water outlet on the heat release side is connected to the city heating network return pipe through the heat pump outlet water supply pipeline, and heat is released to the city heating network return pipe.

[0013] Preferably, the water inlet on the heat release side is connected to the city heating network return pipe through the heat pump inlet return pipeline, and the water outlet on the heat release side is connected to the city heating network water supply pipe through the heat pump outlet water supply pipeline, and releases heat to the city heating network water supply pipe.

[0014] Preferably, the water inlet on the heat release side is connected to the city heat network water supply pipe through a heat network water supply branch pipe, and the water outlet on the heat release side is connected to the city heat network water supply pipe through a heat pump outlet water supply pipeline to release heat to the city heat network water supply pipe.

[0015] Preferably, the heat pump is one of a compression heat pump driven by electrical energy or an absorption heat pump driven by thermal energy, or a mixture of the two.

[0016] Preferably, the heat pump is a one-stage heat pump, or a cascade or multi-stage heat pump composed of at least two-stage heat pumps.

[0017] Preferably, the heat release side water outlet of the heat pump connected to the secondary heating network is provided with a heat supply peak shaving device for heating the water in the secondary heating network and then supplying it to the secondary heating network.

[0018] Preferably, the urban heating network is connected to a heat exchange unit, and the heat exchange unit is connected in parallel with the heat pump to supply heat to the secondary heating network.

[0019] Preferably, in a multi-heat source interconnected heating network system, the return pipe of the city heating network is connected to the return pipes of other district heating networks through pipes or booster pumps and pipes to supply recycled water to the other district heating networks.

[0020] A heat balance method for a system for transporting recycled water using an urban heat network comprises the following steps:

[0021] Supplying recycled water from the recycled water plant to the return water pipe of the urban heating network to supplement the heating network water in the urban heating network;

[0022] Input the hot water from the city heating network return pipe into the heat absorption side of the heat pump, and supply the hot water after cooling and extracting heat to water users;

[0023] The heating network water is input into the heat releasing side of the heat pump, and the heat releasing side releases heat to the urban heating network or the secondary heating network by using the heat absorbed from the heat absorbing side.

[0024] The present invention adopts the above technical solution, which has the following advantages:

[0025] 1. The system and heat balance method for transporting recycled water using the urban heating network provided by the present invention utilize the urban heating network to transport recycled water, and there is no need to build a new dedicated recycled water transportation pipeline, which saves infrastructure costs and reduces the cost of recycled water output.

[0026] 2. The system and heat balance method for transporting recycled water using the urban heating network provided by the present invention absorb the heat of the urban heating network water through the heat absorption side of the heat pump, then heat the absorbed heat to heat the hot network water entering the heat pump through the heat release side, and finally output the heat to the urban heating network or the secondary heating network, thereby reducing the heat loss of the heat source and achieving the heat balance of the urban heating network. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of a system connection for transporting recycled water using a city heating network provided by an embodiment of the present invention;

[0028] Figure 2 is a schematic diagram of the connection between the heat pump and the urban heating network in Example 2 of the present invention;

[0029] Figure 3 is a schematic diagram of the connection between the heat pump and the urban heating network in Example 3 of the present invention;

[0030] Figure 4 is a schematic diagram of the connection between the heat pump and the urban heating network in Example 4 of the present invention;

[0031] Figure 5 is a schematic diagram of the connection between the heat pump and the urban heating network in Example 5 of the present invention;

[0032] Figure 6 is a schematic diagram of the connection between the heat pump and the urban heating network in Example 6 of the present invention;

[0033] Figure 7 is a schematic diagram of the connection between different heat mesh areas in Example 7 of the present invention;

[0034] Figure 8 This is a flow chart of a system heat balance method for transporting recycled water using a city heating network in Example 7 of the present invention.

[0035] Markings in the accompanying drawings:

[0036] 1 is the return pipe of the urban heating network, 2 is the water supply pipe of the urban heating network, 3 is the heat pump, 301 is the heat absorption side, 302 is the heat release side, 4 is the recycled water user, 5 is the driving energy, 6 is the return branch pipe of the heating network, 7 is the water supply branch pipe of the heating network, 8 is the heat pump outlet water supply pipeline, 9 is the heat pump inlet return pipeline, 10 is the heat pump outlet return pipeline, 11 is the recycled water plant, 12 is the water pump, 13 is the water injection point, 14 is the heat exchanger unit, 15 is the secondary heating network, 16 is the heating peak-shaving device, 17 is the heat source, 18 is the booster pump, and 19 is the branch pipe. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "front", "back", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "assembly", "setting", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] The present invention provides a system and heat balance method for transporting recycled water using a city heating network. The system transports recycled water using a city heating network, reduces heat loss from heat sources through heat recovery using a heat pump, achieves an organic combination of city heating network operation and recycled water transport, and improves the economic benefits of recycled water utilization.

[0041] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0042] Example 1

[0043] Reference Figure 1As shown, the system for transporting recycled water using a city heating network provided in this embodiment includes a city heating network, a recycled water plant and a heat pump:

[0044] The urban heating network is used to provide heating for the city; the urban heating network includes an urban heating network return pipe 1 and an urban heating network water supply pipe 2, which are respectively connected to a heat source 17; specifically, the heat source 17 heats the heating network water in the urban heating network, and then outputs the heated heating network water through the urban heating network water supply pipe 2 to provide heating for heat users.

[0045] The reclaimed water plant 11 is connected to the urban heating network return pipe 1 through an injection pipe, and the connection point is an injection point 13; further, a water pump 12 for pressurizing is installed on the injection pipe, and is injected into the urban heating network return pipe 1 through the injection point 13 to replenish the hot network water of the urban heating network.

[0046] In this implementation, the location of the water injection point 13 is determined according to the location of the recycled water plant 11 from the urban heating network. Specifically, the water injection point 13 can be set on the urban heating network return pipe 1 at the entrance of the heat source 17, or it can be set at any position of the urban heating network return pipe 1.

[0047] The heat pump 3 includes a heat absorption side 301 and a heat release side 302, the heat absorption side 301 is an evaporator, and the heat release side 302 is a condenser; the heat absorption side 301 is used to absorb the heat of the hot water network entering it, and the heat release side 301 uses the heat absorbed from the heat absorption side 301 to heat the hot water network entering the heat release side 302; the water inlet of the heat absorption side 301 is connected to the urban hot water network return pipe through the hot water network return branch pipe 6, and the water outlet of the heat absorption side is connected to the water user 4 through a water pipe; the heat release side 302 is connected to the urban hot water network or the secondary hot water network 15 through a water pipe, and releases heat to the urban hot water network or the secondary hot water network 15.

[0048] In this implementation, the water temperature in the heat network return branch pipe 6 is 20°C-50°C, and the water temperature required by the water user 4 is 15°C. The heat of the heat network water in the heat network return branch pipe 6 is absorbed by the heat absorption side 301, so that the temperature of the heat network water is reduced to the temperature of recycled water, such as about 15°C, and then the absorbed heat is heated to enter the heat network water in the heat release side 302, wherein the heat pump 3 recovers heat by the driving energy 5 doing work.

[0049] The urban heating network is connected to at least one heat pump 3 .

[0050] In this embodiment, the heat pump 3 is one of an electric-driven compression heat pump or a thermal-driven absorption heat pump, or a combination of the two. Specifically, the heat pump 3 is a single-stage heat pump, or a cascade or multi-stage heat pump composed of two or more heat pumps.

[0051] Example 2

[0052] Reference Figure 2As shown, the system for transporting recycled water using the urban heating network provided in this embodiment, the water inlet of the heat release side 302 is connected to the urban heating network return pipe 1 through the heat pump inlet return pipe 9, and the water outlet of the heat release side is connected to the urban heating network return pipe 1 through the heat pump outlet return pipe 10, and heat is released to the urban heating network return pipe 1; the heat pump inlet return pipe 9 and the heat pump outlet return pipe 10 are provided with valves between the access points to the urban heating network return pipe 1, and the valve switch size is used to adjust the flow rate according to the heating demand of the heat pump.

[0053] In this implementation, the hot water in the urban hot water network return pipe 1 enters the heat release side 302 of the heat pump 3 through the heat pump inlet return pipeline 9. The heat release side 302 uses the absorbed heat to heat the hot water, thereby increasing the temperature of the hot water in the urban hot water network return pipe 1.

[0054] Example 3

[0055] Reference Figure 3 As shown, the system for transporting recycled water using the urban heating network provided in this embodiment, the water inlet of the heat release side 302 is connected to the urban heating network return pipe 1 through the heat pump inlet return pipeline 9, and the water outlet of the heat release side 302 is connected to the urban heating network water supply pipe 2 through the heat pump outlet water supply pipeline 8, and releases heat to the urban heating network water supply pipe 2.

[0056] In this implementation, the hot network water in the urban heating network return pipe 1 enters the heat release side 302 of the heat pump 3 through the heat pump inlet return pipeline 9. The heat release side 302 uses the absorbed heat to heat the hot network water entering it, and then outputs it to the urban heating network supply pipe 2 through the heat pump outlet water supply pipeline 8.

[0057] Example 4

[0058] Reference Figure 4 As shown, the system provided by this embodiment utilizes the city heating network to transport recycled water, the water inlet of the heat release side 302 is connected to the city heating network water supply pipe 2 through the heating network water supply branch pipe 7, and the water outlet of the heat release side 302 is connected to the city heating network water supply pipe 2 through the heat pump outlet water supply pipeline 8, and releases heat to the city heating network water supply pipe 2.

[0059] In this implementation, the hot network water in the urban hot network water supply pipe 2 enters the heat release side 302 of the heat pump 3 through the hot network water supply branch pipe 7. The heat release side 302 uses the absorbed heat to heat the hot network water, and then outputs it to the urban hot network water supply pipe 2 through the heat pump outlet water supply pipeline 8, thereby increasing the water supply temperature in the urban hot network water supply pipe 2.

[0060] Example 5

[0061] Reference Figure 5As shown, the system for transporting recycled water using the urban heating network provided in this embodiment, the heat release side 302 of the heat pump 3 is connected to the secondary heating network 15, and a heat peak-shaving device 16 is provided at the water outlet of the heat release side 302, which is used to heat the water in the secondary heating network and then supply it to the secondary heating network 15, so as to further ensure the water supply temperature of the secondary network.

[0062] Example 6

[0063] Reference Figure 6 As shown, in the system for transporting recycled water using the urban heating network provided in this embodiment, the urban heating network is connected to the heat exchanger 14, the water outlet at one end of the heat exchanger 14 is connected to the urban heating network return pipe 1, and the water inlet at one end of the heat exchanger 14 is connected to the urban heating network water supply pipe 2; the other end of the heat exchanger 14 is connected to the secondary heating network 15. The heat exchanger 14 is connected in parallel with the heat pump 3, the heat release side 302 of the heat pump 3 is connected to the secondary heating network 15, and the heat exchanger 14 and the heat pump 3 are connected in parallel to jointly supply heat to the secondary heating network.

[0064] In the present invention, the heat pump 3 can be connected to the urban heating network in a variety of ways, and can be connected to the urban heating network in a mixed manner; Figure 1 The system includes five heat pumps 3, and the five heat pumps 3 are connected to the urban heating network in different access modes to better achieve the thermal balance of the system.

[0065] Example 7

[0066] Reference Figure 7 As shown, the system for transporting recycled water using the urban heating network provided in this embodiment, the urban heating network return pipe 1 is connected to the return pipes 1 of other heating network areas through pipelines, and is used to supply recycled water to other heating network areas.

[0067] Specifically, the recycled water plant 11 injects recycled water from the injection point 13 into the urban heating network A via the injection pipe and the water pump 12. The heating network area B and the heating network area C have independent heat sources 17. During the heating season, the urban heating network A and the heating network areas B and C are each independently closed-circulated. If there are recycled water users 4 in the heating network areas B and C, the return water pipelines of the urban heating network A and the heating network area B are connected. If the return water pressure of the heating network area B at the connection point is higher than the return water pressure of the urban heating network A, the return water trunk line at the connection between the urban heating network A and the heating network area B is connected through a branch pipe and a pressurized water pump 18 for the recycled water users 4 in the heating network area B. Connect the return water pipelines of heating network B and heating network C. If the return water pressure of heating network area B at the connection point is higher than the return water pressure of heating network area C, connect the return water trunk lines at the connection between heating network area B and heating network area C through branch pipe 19 for recycled water users 4 in heating network area C.

[0068] The system of the present invention using the urban heating network to transport recycled water, referring to Figure 1The connection methods in the above embodiments can be combined to form a system for transporting recycled water, so as to better achieve thermal balance of the system.

[0069] Example 8

[0070] Reference Figure 8 As shown, the heat balance method of the system using the urban heating network to transport recycled water provided in this embodiment includes the following steps:

[0071] S01, supplying the recycled water from the recycled water plant 11 to the urban heating network return pipe 1 to replenish the heating network water in the urban heating network;

[0072] S02, inputting the hot water of the city heating network return pipe 1 into the heat absorption side 301 of the heat pump 3, and supplying the hot water after cooling and extracting heat to the water user 4;

[0073] S03, the hot water of the city heating network is input to the heat release side 302 of the heat pump 3, and the heat release side 302 releases heat to the city heating network or the secondary heating network 15 using the heat absorbed from the heat absorption side 301.

[0074] In this example, in step S03, the water inlet and outlet of the heat release side 302 can be connected to the urban heating network return pipe 1 respectively, and heat is released to the urban heating network return pipe 1; the water inlet of the heat release side 302 can also be connected to the urban heating network return pipe 1, and the water outlet of the heat release side 302 can be connected to the urban heating network water supply pipe 2, and heat is released to the urban heating network water supply pipe 2; the water inlet and outlet of the heat release side 302 can also be connected to the urban heating network water supply pipe 2 respectively, and heat is released to the urban heating network water supply pipe 2; various connection methods of the heat release side 302 and the urban heating network achieve thermal balance of the system.

[0075] The present invention changes the closed circulation system of the original urban heating network into an open system with injection and extraction. In order to avoid heat loss in the heating network system, it is necessary to maintain the same water temperature for injection and extraction. The present invention uses a heat pump 3 to absorb heat and cool the hot network water in the urban heating network return pipe 1, and then transports it to the recycled water user 4 for use. At the same time, the heat pump 3 returns the heat recovered by the driving energy 5 to the urban heating network. After multiple cycles, the hot network water in the urban heating network is all recycled water input by the recycled water plant 11. For large-scale production water users 4, a centralized heat pump station can be built to recover heat and use the heat to heat the hot network water. For dispersed water users, the heat pump 3 can be used in combination with the thermal power station to recover heat and use the heat for heating the secondary heating network 15. The change in the heat supply of the secondary heating network 15 is regulated by the heating peak-shaving device 16 or by the heat exchanger unit 14 for flow regulation.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for transporting recycled water using an urban heating network, characterized in that: include: The urban heating network is used to provide heating for the city; the urban heating network includes an urban heating network return pipe and an urban heating network water supply pipe; A recycled water plant, which is connected to the return water pipe of the urban heating network through a water injection pipe and is used to replenish the heating network water in the urban heating network; A heat pump, comprising a heat absorbing side and a heat releasing side, wherein the heat absorbing side is used to absorb the heat of the water in the heating network entering the heat pump, and the heat releasing side uses the heat absorbed from the heat absorbing side to heat the water in the heating network entering the heat pump; the water inlet of the heat absorbing side is connected to the water return pipe of the urban heating network through the water return branch pipe of the heating network, and the water outlet of the heat absorbing side is connected to the water user through a water pipe; the heat releasing side is connected to the urban heating network or the secondary heating network through the water pipe, and releases heat to the urban heating network or the secondary heating network; The urban heating network is connected to at least one of the heat pumps; The water inlet of the heat release side is connected to the return pipe of the city heating network through the heat pump inlet return pipe, and the water outlet of the heat release side is connected to the return pipe of the city heating network through the heat pump outlet water supply pipe, and releases heat to the return pipe of the city heating network; The water inlet on the heat release side is connected to the city heating network return pipe through the heat pump inlet return pipeline, and the water outlet on the heat release side is connected to the city heating network water supply pipe through the heat pump outlet water supply pipeline, and releases heat to the city heating network water supply pipe.

2. The system for transporting recycled water using the urban heating network according to claim 1, characterized in that: The water inlet on the heat release side is connected to the city heat network water supply pipe through the heat network water supply branch pipe, and the water outlet on the heat release side is connected to the city heat network water supply pipe through the heat pump outlet water supply pipeline to release heat to the city heat network water supply pipe.

3. The system for transporting recycled water using the urban heating network according to claim 1, characterized in that: The heat pump is one of a compression heat pump driven by electrical energy or an absorption heat pump driven by thermal energy, or a mixture of the two.

4. The system for transporting recycled water using the urban heating network according to claim 3, characterized in that: The heat pump is a one-stage heat pump, or a cascade or multi-stage heat pump composed of at least two-stage heat pumps.

5. The system for transporting recycled water using the urban heating network according to claim 1, characterized in that: The heat release side water outlet of the heat pump connected to the secondary heating network is provided with a heat supply peak shaving device for heating the water in the secondary heating network and then supplying it to the secondary heating network.

6. The system for transporting recycled water using the urban heating network according to claim 1, characterized in that: The urban heating network is connected to a heat exchange unit, and the heat exchange unit is connected in parallel with the heat pump to supply heat to the secondary heating network.

7. The system for transporting recycled water using the urban heating network according to claim 1, characterized in that: In a multi-heat source interconnected heating network system, the return pipe of the city heating network is connected to the return pipes of other district heating networks through pipes or booster pumps and pipes to supply recycled water to the other district heating networks.

8. The heat balance method of a system for transporting recycled water using an urban heating network according to any one of claims 1 to 7, characterized in that: Includes steps: Supplying recycled water from the recycled water plant to the return water pipe of the urban heating network to supplement the heating network water in the urban heating network; Input the hot water from the city heating network return pipe into the heat absorption side of the heat pump, and supply the hot water after cooling and extracting heat to water users; The heating network water is input into the heat releasing side of the heat pump, and the heat releasing side releases heat to the urban heating network or the secondary heating network by using the heat absorbed from the heat absorbing side.

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