A heat network low-temperature return water super-cooling heat unit and a method for operating the same

Abstract

In the field of energy utilization, heat exchange process is widely used, especially in industrial production and civil heating and cooling fields. Heat can only spontaneously transfer from high-temperature objects to low-temperature objects, and the outlet temperature of the hot fluid needs to be higher than the inlet temperature of the cold fluid. In particular, in the field of civil heating, the outlet temperature of the primary network hot water needs to be reduced to a lower level than the inlet temperature of the secondary network to improve the pipe network delivery capacity and reduce the energy consumption and carbon emissions of heating. In order to achieve the purpose of reducing the outlet temperature of the primary network hot water to a significantly lower level than the inlet temperature of the secondary network, the invention proposes a heat network low-temperature return water super-cooling and heating unit and its operation method, which uses temperature potential energy conversion to mechanical work to realize the beneficial effect of reverse heat exchange, and breaks through the lower limit of the return water temperature of the primary network compared with the prior art, thereby significantly improving the heat exchange efficiency and reducing the heating cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of energy utilization, in particular relates to a cold and heat unit for deep heat exchange between primary network and secondary network and a running method thereof. BACKGROUND

[0002] In the field of energy utilization, heat exchange process is needed in large quantities, especially in the field of industrial production and civil heating and cooling. According to the second law of thermodynamics, heat can only spontaneously transfer from a high-temperature object to a low-temperature object. Even if the reverse flow heat exchange is used, the outlet temperature of the hot fluid needs to be higher than the inlet temperature of the cold fluid. From the perspective of general heat exchange, especially in the field of civil heating, the outlet temperature of the primary network hot water needs to be reduced to a level lower than the inlet temperature of the secondary network, which will produce significant beneficial effects:

[0003] (1) The temperature difference of the primary network supply and return water is significantly increased, which greatly improves the heating load of the primary pipe network without increasing the flow of the primary network, thereby reducing the investment of the pipe network and significantly increasing the heating area.

[0004] (2) The lower return water of the primary network can be used to recover industrial waste heat, such as power plant exhaust steam and industrial low-pressure waste steam, thereby significantly reducing the cost of heating.

[0005] In order to realize the full heat exchange between the primary network hot water and the secondary network hot water, significantly improve the heat exchange efficiency of the heat exchange process, and reduce the outlet temperature of the primary network hot water to a level significantly lower than the inlet temperature of the secondary network, fully utilize the internal energy of different temperature fluids, and thereby achieve a heat exchange efficiency significantly higher than the existing technology, the present application proposes a super cold and heat unit for low-temperature return water of the heat network and a running method thereof. SUMMARY

[0006] In order to realize the small irreversible loss heat exchange between the primary network hot water and the secondary network hot water, break through the limit of heat exchange temperature difference, and significantly break through the upper limit of heat exchange efficiency compared with the existing technology, the present application proposes a super cold and heat unit for low-temperature return water of the heat network and a running method thereof.

[0007] The application provides a heat network low-temperature return water super-cooling heat unit and a running method thereof, which comprises a primary network inlet (1), a primary network outlet (2), a secondary network inlet (3), a secondary network outlet (4), a high-temperature cavity (5), a low-temperature cavity (6), a pressure booster (7), a pressure reducer (8) and an energy extractor (9), wherein the primary network is cooled in the high-temperature cavity (5) and the low-temperature cavity (6) in sequence, the secondary network is heated in the low-temperature cavity (6) and the high-temperature cavity (5) in sequence, the high-temperature cavity (5) is connected with the primary network inlet (1), the secondary network outlet (4) and the low-temperature cavity (6), the low-temperature cavity (6) is connected with the primary network outlet (2), the secondary network inlet (3) and the high-temperature cavity (5), the pressure booster (7) and the pressure reducer (8) are installed in the low-temperature cavity (6), the pressure booster (7) sends the working medium on the left side of the low-temperature cavity (6) into the cavity on the right side of the low-temperature cavity (6) after boosting the pressure, the pressure reducer (8) sends the working medium on the right side of the low-temperature cavity (6) into the cavity on the left side of the low-temperature cavity (6) after reducing the pressure, the working medium reciprocates, the energy extractor (9) converts the temperature difference potential energy of the primary network hot water and the secondary network hot water into mechanical work or electric energy for driving the pressure booster (7), the energy extractor (9) automatically adjusts the efficiency of converting the temperature difference potential energy into mechanical work or electric energy according to the set outlet temperature of the primary network and the secondary network, when the outlet temperature of the primary network is lower than the set value or the outlet temperature of the secondary network is higher than the set value, the energy extractor (9) automatically increases the evaporation and condensation temperature difference of the circulating working medium in the energy extractor (9) to reduce the efficiency of converting the temperature difference potential energy into mechanical work or electric energy, so as to reduce the work or power generation, when the outlet temperature of the primary network is higher than the set value or the outlet temperature of the secondary network is lower than the set value, the energy extractor (9) automatically reduces the evaporation and condensation temperature difference of the circulating working medium in the energy extractor (9) to improve the efficiency of converting the temperature difference potential energy into mechanical work or electric energy, so as to improve the work or power generation.

[0008] The circulating working medium in the low-temperature cavity (6) is organic matter, inorganic matter or natural working medium.

[0009] The energy extractor (9) adopts a low-boiling-point working medium in a closed cycle, the working medium is heated and evaporated into high-pressure steam in the closed pipeline on the left side of the high-temperature cavity (5) by the primary network hot water, the steam drives the blade to do work, the working medium is cooled into low-pressure liquid in the closed pipeline on the right side of the high-temperature cavity (5) by the secondary network hot water, and then returns to the left side of the high-temperature cavity (5) to reciprocate.

[0010] The pressure booster (7) is a piston type, vortex type, centrifugal type, screw type or magnetic suspension type pressure booster.

[0011] The pressure reducer (8) is a hole plate type, capillary type or valve type.

[0012] The aforementioned low-temperature return water super heat and cold unit for heating networks and its operation method, wherein the energy extractor (9) adopts a temperature difference power machine, a temperature difference generator, or a heat exchanger. Attached Figure Description

[0013] Figure 1 Diagram of a low-temperature return water super chiller / heater unit system for a heating network;

[0014] Figure 2 This is a system diagram of a low-temperature return water super chiller unit for circulating the working fluid within the pipe of a heating network.

[0015] Figure 3 This is a system diagram of a low-temperature return water super chiller unit for a heating network used in a two-stage working fluid cycle.

[0016] Figure 4 This is a system diagram of a super chiller / heater unit for separating high and low temperature chambers in a heating network with low-temperature return water.

[0017] Figure 5 This is a system diagram of a low-temperature return water super-cooling and heating unit for heat exchange of secondary network hot water for different users.

[0018] Figure label:

[0019] 1- Primary network inlet, 2- Primary network outlet, 3- Secondary network inlet, 3A- User A secondary network inlet, 3B- User B secondary network inlet, 4- Secondary network outlet, 4A- User A secondary network outlet, 4B- User B secondary network outlet, 5- High-temperature chamber, 6- Low-temperature chamber, 7- Booster, 7A- Low-pressure booster, 7B- High-pressure booster, 8- Reducer, 8A- Low-pressure reducer, 8B- High-pressure reducer, 9- Energy extractor Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this invention. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this invention, and should not be construed as limiting the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] As attached Figure 1 As shown, attached Figure 1The system diagram of a super cold heat unit for a low-temperature return water of a heat network, the unit comprising a primary network inlet (1), a primary network outlet (2), a secondary network inlet (3), a secondary network outlet (4), a high-temperature cavity (5), a low-temperature cavity (6), a pressure booster (7), a pressure reducer (8) and an energy extractor (9), wherein the primary network is cooled in the high-temperature cavity (5) and the low-temperature cavity (6) in sequence, the secondary network is heated in the low-temperature cavity (6) and the high-temperature cavity (5) in sequence, the high-temperature cavity (5) is connected with the primary network inlet (1), the secondary network outlet (4) and the low-temperature cavity (6), the low-temperature cavity (6) is connected with the primary network outlet (2), the secondary network inlet (3) and the high-temperature cavity (5), the pressure booster (7) and the pressure reducer (8) are installed in the low-temperature cavity (6), wherein the pressure booster (7) boosts the working medium on the left side of the low-temperature cavity (6) and sends it into the right cavity of the low-temperature cavity (6), the pressure reducer (8) reduces the pressure of the working medium on the right side of the low-temperature cavity (6) and sends it into the left cavity of the low-temperature cavity (6) to realize the reciprocating circulation of the working medium.

[0022] In this embodiment, the circulating working medium in the low-temperature cavity (6) is carbon dioxide, the energy extractor (9) in the high-temperature cavity (5) is a temperature difference working machine, the pressure booster (7) is a centrifugal pressure booster driven by the temperature difference working machine, and the pressure reducer (8) is a valve type. The inlet temperature of the primary network hot water is 100℃, the outlet temperature of the primary network is 5℃, the inlet temperature of the secondary network is 30℃, and the outlet temperature of the secondary network is 50℃.

[0023] As shown in the accompanying drawings, Figure 2 as shown in the accompanying drawings, Figure 2The application relates to a system diagram for a heat network low-temperature return water super-cooling heat unit for circulating in a working medium pipe, which comprises a primary network inlet (1), a primary network outlet (2), a secondary network inlet (3), a secondary network outlet (4), a high-temperature cavity (5), a low-temperature cavity (6), a pressure booster (7), a pressure reducer (8) and an energy extractor (9), wherein the primary network is cooled in the high-temperature cavity (5) and the low-temperature cavity (6) in sequence, the secondary network is heated in the low-temperature cavity (6) and the high-temperature cavity (5) in sequence, the high-temperature cavity (5) is connected with the primary network inlet (1), the secondary network outlet (4) and the low-temperature cavity (6), the low-temperature cavity (6) is connected with the primary network outlet (2), the secondary network inlet (3) and the high-temperature cavity (5), the pressure booster (7) and the pressure reducer (8) are installed in the low-temperature cavity (6), the pressure booster (7) sends the working medium on the left side of the low-temperature cavity (6) to the right side of the low-temperature cavity (6) after boosting the pressure, the pressure reducer (8) sends the working medium on the right side of the low-temperature cavity (6) to the left side of the low-temperature cavity (6) after reducing the pressure, and the working medium reciprocally circulates. In the embodiment, the circulating working medium in the low-temperature cavity (6) flows in a closed pipe, the primary network hot water and the secondary network hot water flow outside the closed pipe, the circulating working medium in the closed pipe is water, the energy extractor (9) in the high-temperature cavity (5) is a thermoelectric generator, the pressure booster (7) is a screw type pressure booster and is driven by the thermoelectric generator, and the pressure reducer (8) is a hole plate type. The primary network hot water inlet temperature is 80 DEG C, the primary network outlet temperature is 20 DEG C, the secondary network inlet temperature is 40 DEG C, and the secondary network outlet temperature is 55 DEG C.

[0024] As shown in the accompanying drawings Figure 3 As shown in the accompanying drawings Figure 3This is a system diagram of a super chiller unit with low-temperature return water for a heating network used in a two-stage working fluid cycle. The unit consists of a primary network inlet (1), a primary network outlet (2), a secondary network inlet (3), a secondary network outlet (4), a high-temperature chamber (5), a low-temperature chamber (6), a booster (7), a pressure reducer (8), and an energy extractor (9). The primary network cools down in the high-temperature chamber (5) and the low-temperature chamber (6) sequentially, while the secondary network heats up in the low-temperature chamber (6) and the high-temperature chamber (5) sequentially. The high-temperature chamber (5) is connected to the primary network inlet (1), the secondary network outlet (4), and the low-temperature chamber (6), and the low-temperature chamber (6) is connected to the primary network outlet (2). The secondary network inlet (3) is connected to the high temperature chamber (5). The low temperature chamber (6) is equipped with two complete working fluid circulation stages. The low pressure booster (7A) pressurizes the working fluid on the left side of the low temperature chamber (6) and sends it into the empty cavity on the right side of the low temperature chamber (6). The low pressure reducer (8A) depressurizes the working fluid on the right side of the low temperature chamber (6) and sends it into the empty cavity on the left side of the low temperature chamber (6) for reciprocating circulation. The working fluid is carbon dioxide. The high pressure booster (7B) pressurizes the working fluid on the left side of the low temperature chamber (6) and sends it into the empty cavity on the right side of the low temperature chamber (6). The high pressure reducer (8B) depressurizes the working fluid on the right side of the low temperature chamber (6) and sends it into the empty cavity on the left side of the low temperature chamber (6) for reciprocating circulation. In this embodiment, the circulating working fluid in the low-temperature chamber (6) flows within a closed pipe, while the primary and secondary hot water flows outside this closed pipe. The circulating working fluid within the closed pipe is water. The energy extractor (9) in the high-temperature chamber (5) is a thermoelectric generator. The low-pressure booster (7A) is a vortex booster, and the high-pressure booster (7B) is a screw booster. Both boosters are driven by the thermoelectric generator. The low-pressure pressure reducer (8A) uses an electric valve, and the high-pressure pressure reducer (8B) uses an orifice plate. The primary hot water inlet temperature is 130°C, the primary network outlet temperature is 5°C, the secondary network inlet temperature is 45°C, and the secondary network outlet temperature is 60°C.

[0025] As attached Figure 4 As shown, attached Figure 4 This is a system diagram of a super chiller / heater unit for high and low temperature chamber separation in a heating network with low-temperature return water, and attached. Figure 2The difference of the flow is that the left and right cavities of the high pressure cavity (5) and the low pressure cavity (6) are connected by the primary network and the secondary network respectively, and the unit comprises a primary network inlet (1), a primary network outlet (2), a secondary network inlet (3), a secondary network outlet (4), a high temperature cavity (5), a low temperature cavity (6), a booster (7) and a pressure reducer (8), wherein the primary network is cooled in the high temperature cavity (5) and the low temperature cavity (6) in turn, and the secondary network is heated in the low temperature cavity (6) and the high temperature cavity (5) in turn, the high temperature cavity (5) adopts a plate heat exchanger, the high temperature cavity (5) is connected with the primary network inlet (1), the secondary network outlet (4) and the low temperature cavity (6), the low temperature cavity (6) is connected with the primary network outlet (2), the secondary network inlet (3) and the high temperature cavity (5), the booster (7) and the pressure reducer (8) are installed in the low temperature cavity (6), wherein the booster (7) sends the working medium on the left side of the low temperature cavity (6) to the right cavity of the low temperature cavity (6) after boosting the pressure, the pressure reducer (8) sends the working medium on the right side of the low temperature cavity (6) to the left cavity of the low temperature cavity (6) after reducing the pressure, so as to realize the reciprocating circulation of the working medium. In the embodiment, the circulating working medium in the low temperature cavity (6) flows in the closed pipeline, the primary network hot water and the secondary network hot water flow outside the closed pipeline, the circulating working medium in the closed pipeline is tetrafluoroethane, the high temperature cavity (5) is a plate heat exchanger, the booster (7) is a vortex booster driven by external power, and the pressure reducer (8) is a capillary type. The inlet temperature of the primary network hot water is 60℃, the outlet temperature of the primary network is 5℃, the inlet temperature of the secondary network is 30℃, and the outlet temperature of the secondary network is 40℃.

[0026] As shown in the accompanying drawings Figure 5 As shown in the accompanying drawings Figure 5 It is a system diagram of a heat network low temperature return water super cold heat unit for different user secondary network hot water heat exchange, and the accompanying drawings Figure 4The flow is different in that the high-pressure cavity (5) and the low-pressure cavity (6) are used for heating secondary nets of different users respectively, and the unit set comprises a primary net inlet (1), a primary net outlet (2), a secondary net inlet (3), a secondary net outlet (4), a high-temperature cavity (5), a low-temperature cavity (6), a pressure booster (7) and a pressure reducer (8), wherein the primary net is subjected to temperature reduction in the high-temperature cavity (5) and the low-temperature cavity (6) in sequence, and the secondary nets of different users are subjected to temperature rise in the low-temperature cavity (6) and the high-temperature cavity (5) respectively, the high-temperature cavity (5) is connected with the primary net inlet (1), the secondary net inlet (3B) of user B, the secondary net outlet (4B) of user B and the low-temperature cavity (6), the low-temperature cavity (6) is connected with the primary net outlet (2), the secondary net inlet (3A) of user A, the secondary net outlet (4A) of user A and the high-temperature cavity (5), the pressure booster (7) and the pressure reducer (8) are installed in the low-temperature cavity (6), wherein the pressure booster (7) boosts the pressure of the working medium in the left pipeline of the low-temperature cavity (6) and sends it into the right cavity of the low-temperature cavity (6), and the pressure reducer (8) reduces the pressure of the working medium in the right side of the low-temperature cavity (6) and sends it into the left cavity of the low-temperature cavity (6) to realize the reciprocating circulation of the working medium. In this embodiment, the circulating working medium in the low-temperature cavity (6) flows in the closed pipeline, the primary net hot water and the secondary net hot water flow outside the closed pipeline, the circulating working medium in the closed pipeline is tetrafluoroethane, the high-temperature cavity (5) is a plate heat exchanger, the pressure booster (7) is a magnetic suspension type pressure booster and is driven by external power, and the pressure reducer (8) is a capillary type. The inlet temperature of the primary net hot water is 90℃, the outlet temperature of the primary net is 3℃, the inlet temperature of the secondary net of user A is 35℃, the outlet temperature of the secondary net of user A is 45℃, the inlet temperature of the secondary net of user B is 45℃, and the outlet temperature of the secondary net of user B is 60℃.

[0027] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to some technical features thereof, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A heat network low-temperature return water super-cooling heat unit, characterized in that: The machine set comprises a primary net inlet (1), a primary net outlet (2), a secondary net inlet (3), a secondary net outlet (4), a high-temperature cavity (5), a low-temperature cavity (6), a pressure booster (7), a pressure reducer (8) and an energy extractor (9), wherein the primary net is cooled in the high-temperature cavity (5) and the low-temperature cavity (6) in sequence, the secondary net is heated in the low-temperature cavity (6) and the high-temperature cavity (5) in sequence, the high-temperature cavity (5) is connected with the primary net inlet (1), the secondary net outlet (4) and the low-temperature cavity (6), the low-temperature cavity (6) is connected with the primary net outlet (2), the secondary net inlet (3) and the high-temperature cavity (5), the pressure booster (7) and the pressure reducer (8) are installed in the low-temperature cavity (6), wherein the pressure booster (7) boosts the pressure of the working medium on the left side of the low-temperature cavity (6) and sends it into the cavity on the right side of the low-temperature cavity (6), the pressure reducer (8) reduces the pressure of the working medium on the right side of the low-temperature cavity (6) and sends it into the cavity on the left side of the low-temperature cavity (6) to realize the reciprocating circulation of the working medium, the energy extractor (9) converts the temperature difference potential energy of the hot water of the primary net and the hot water of the secondary net into mechanical work or electric energy to drive the pressure booster (7), the energy extractor (9) adopts a low-boiling-point working medium in a closed cycle, the working medium is heated, evaporated and changed into high-pressure steam in the closed pipeline on the left side of the high-temperature cavity (5) by the hot water of the primary net, the steam drives the blades to do work, the working medium is cooled, changed into low-pressure liquid in the closed pipeline on the right side of the high-temperature cavity (5) by the hot water of the secondary net and then returns to the left side of the high-temperature cavity (5) to realize the reciprocating circulation, the energy extractor (9) automatically adjusts the efficiency of the conversion of the temperature difference potential energy into mechanical work or electric energy according to the set outlet temperature of the hot water of the primary net and the hot water of the secondary net, when the outlet temperature of the primary net is lower than the set value or the outlet temperature of the secondary net is higher than the set value, the energy extractor (9) automatically increases the evaporation and condensation temperature difference of the circulating working medium in the energy extractor (9) to reduce the efficiency of the conversion of the temperature difference potential energy into mechanical work or electric energy to reduce the work amount or the power generation amount, when the outlet temperature of the primary net is higher than the set value or the outlet temperature of the secondary net is lower than the set value, the energy extractor (9) automatically reduces the evaporation and condensation temperature difference of the circulating working medium in the energy extractor (9) to improve the efficiency of the conversion of the temperature difference potential energy into mechanical work or electric energy to improve the work amount or the power generation amount.

2. The heat-supply network low-temperature return water supercooling heat unit according to claim 1, characterized in that: The energy extractor (9) is a temperature difference work machine, a temperature difference generator or a heat exchanger.

3. The heat-supply network low-temperature return water supercooling heat unit according to claim 1, characterized in that: The circulating working medium in the low-temperature cavity (6) is a natural working medium.

4. The heat-supply network low-temperature return water supercooling heat unit according to claim 1, characterized in that: The pressure booster (7) is a piston type, a scroll type, a centrifugal type, a screw type or a magnetic suspension type.

5. The heat-supply network low-temperature return water supercooling heat unit according to claim 1, characterized in that: The pressure reducer (8) is a hole plate type, a capillary type or a valve type.

6. The heat-supply network low-temperature return water supercooling heat unit according to claim 1, characterized in that: The high-temperature cavity (5) and the low-temperature cavity (6) are respectively used for heating the secondary nets of different users.

7. The heat-supply network low-temperature return water supercooling heat unit according to claim 1, characterized in that: The circulating medium in the closed pipeline inside the low-temperature cavity (6) exchanges heat with the primary net and the secondary net outside the pipeline.

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