Hot water supply system

Abstract

The present invention relates to a hot water supply system, comprising a first heat pump, a second heat pump and a coupling device; the first heat pump comprises a first evaporator, a generator and an absorber, the first evaporator is provided with a first heat source inlet and a first heat source outlet, the generator is provided with a second heat source inlet and a second heat source outlet, and the absorber is provided with a first hot water inlet and a first hot water outlet; the second heat pump comprises a compressor and a second condenser, the second condenser is provided with a second hot water inlet and a second hot water outlet; the coupling device is connected to the first heat pump and forms a first condenser of the first heat pump, and the coupling device is connected to the second heat pump and forms a second evaporator of the second heat pump. The hot water supply system can recycle and utilize low-grade heat sources of 50°C to 70°C existing in the industrial field, thereby improving heat recovery efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of hot water supply, and in particular to a hot water supply system. Background Art

[0002] The second type of absorption heat pump can use a large amount of medium-temperature heat sources to generate a small amount of high-temperature useful heat energy. It is usually used to use industrial waste water as a heat source to produce higher temperature hot water or steam for use. However, the heat source water temperature range required by conventional second-type absorption heat pumps is generally 70℃~90℃, and only part of the waste heat can be recovered to produce higher temperature hot water, which is inefficient. And when producing higher temperature hot water, most of the heat must be discharged into the environment through cooling water. In the industrial field, there are a large number of low-grade heat sources at 50℃~70℃. At the usual cooling water temperature, such heat sources are difficult to meet the requirements of conventional second-type absorption heat pumps and cannot operate. Therefore, low-grade heat sources at 50℃~70℃ can only be discharged by cooling, resulting in energy waste.

[0003] How to recycle and utilize the low-grade heat sources of 50°C to 70°C existing in the industrial field and improve the heat recovery efficiency is a technical problem that technicians in this field need to solve. Summary of the invention

[0004] The object of the present invention is to provide a hot water supply system which can recycle low-grade heat sources of 50°C to 70°C existing in the industrial field and improve heat recovery efficiency.

[0005] To solve the above technical problems, the present invention provides a hot water supply system, including a first heat pump, a second heat pump and a coupling device; the first heat pump includes a first evaporator, a generator and an absorber, the first evaporator is provided with a first heat source inlet and a first heat source outlet, the generator is provided with a second heat source inlet and a second heat source outlet, and the absorber is provided with a first hot water inlet and a first hot water outlet; the second heat pump includes a compressor and a second condenser, the second condenser is provided with a second hot water inlet and a second hot water outlet; the coupling device is connected to the first heat pump and forms a first condenser of the first heat pump, and the coupling device is connected to the second heat pump and forms a second evaporator of the second heat pump.

[0006] The coupling device can play the role of the first condenser in the first heat pump and participate in the refrigerant (water) circulation in the first heat pump. The first heat pump is a second-type absorption heat pump. The combination of solution and refrigerant can be various. The most commonly used combination is that the solution is lithium bromide solution and the refrigerant is water. The present invention takes this as an example. At the same time, the coupling device can also play the role of the second evaporator in the second heat pump and participate in the refrigerant circulation. The second heat pump is a vapor compression heat pump. The most commonly used refrigerant working fluids are R134a, R245fa, etc.

[0007] By setting the coupling device, the first condenser of the first heat pump can supply heat to the second evaporator of the second heat pump. While the refrigerant passing through the second evaporator can evaporate, the water condensed by the first condenser can reach a lower temperature, and the internal pressure of the first condenser decreases. In this way, the generator connected to the first condenser can evaporate and concentrate the lithium bromide solution at a lower temperature, and at the same time can absorb more heat from the low-grade heat source, and the first evaporator also absorbs the heat from the low-grade heat source to evaporate the refrigerant (water), so that the low-grade heat source with a temperature in the range of 50°C to 70°C can be fully utilized to prepare hot water with a higher temperature, thereby solving the problem of recycling and utilizing a large number of low-grade heat sources with a temperature of 50°C to 70°C in the industrial field and improving the heat recovery efficiency.

[0008] Optionally, the first hot water inlet and the second hot water outlet are connected.

[0009] Optionally, the first heat source outlet is connected to the second heat source inlet.

[0010] Optionally, a first heat exchanger is further included, the second heat source outlet is connected to the third heat source inlet 43 of the first heat exchanger, the first heat exchanger further includes a third hot water inlet and a third hot water outlet, the third hot water outlet is connected to the first hot water inlet and / or the second hot water inlet.

[0011] Optionally, the coupling device includes the first condenser, the second evaporator, and a circulation loop connected between the first condenser and the second evaporator, and the circulation loop is connected to a water pump.

[0012] Optionally, the coupling device also includes a second heat exchanger, which is connected between the first condenser and the second evaporator. The water in the circulation loop can enter the second evaporator from the first condenser through the second heat exchanger, and the second heat source outlet is connected to the fourth heat source inlet of the second heat exchanger.

[0013] Optionally, the circulation loop is further connected to a water tank, and the medium in the circulation loop can flow from the second evaporator through the water tank and through the first condenser.

[0014] Optionally, the second heat pump further includes an economizer, which is respectively connected to the compressor, the second condenser and the second evaporator, and the compressor is a two-stage compressor.

[0015] Optionally, a flash tank is further included, and the flash tank is connected to the first hot water outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1is a schematic diagram of a first embodiment of a hot water supply system provided by an embodiment of the present invention;

[0017] Figure 2 is a schematic diagram of a second embodiment of a hot water supply system provided by an embodiment of the present invention;

[0018] Figure 3 is a schematic diagram of a third embodiment of a hot water supply system provided by an embodiment of the present invention;

[0019] Figure 4 Schematic diagram of a fourth embodiment of a hot water supply system provided in an embodiment of the present invention.

[0020] Attached Figure 1-Figure 4 In the figure, the reference numerals are described as follows:

[0021] 1-first heat pump, 11-first evaporator, 12-generator, 13-absorber, 14-first hot water inlet, 15-first hot water outlet, 16-first heat source inlet, 17-first heat source outlet, 18-second heat source inlet, 19-second heat source outlet;

[0022] 2-second heat pump, 21-compressor, 22-second condenser, 23-second hot water inlet, 24-second hot water outlet, 25-economizer;

[0023] 3-coupling device, 31-first condenser, 32-second evaporator, 33-circulation loop, 34-water pump, 35-second heat exchanger, 36-fourth heat source inlet, 37-fourth heat source outlet, 38-water tank;

[0024] 4-first heat exchanger, 41-third hot water inlet, 42-third hot water outlet, 43-third heat source inlet, 44-third heat source outlet;

[0025] 5- flash tank, 51- steam outlet, 52- drain outlet. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] like Figure 1As shown, the hot water supply system provided in this embodiment includes a first heat pump 1, a second heat pump 2 and a coupling device 3, wherein the first heat pump 1 includes a first evaporator 11, a generator 12 and an absorber 13, the first evaporator 11 is provided with a first heat source inlet 16 and a first heat source outlet 17, the generator 12 is provided with a second heat source inlet 18 and a second heat source outlet 19, the absorber 13 is provided with a first hot water inlet 14 and a first hot water outlet 15, the second heat pump 2 includes a compressor 21 and a second condenser 22, and the second condenser 22 is provided with a second hot water inlet 23 and a second hot water outlet 24.

[0028] The coupling device 3 is connected to the first heat pump 1 and the second heat pump 2 respectively. Specifically, the coupling device 3 is connected to the first heat pump 1 and forms a first condenser 31 of the first heat pump 1. At this time, the first heat pump 1 includes a first evaporator 11, a generator 12, an absorber 13 and a first condenser 31. The first heat pump 1 is a second-type absorption heat pump. The combination of solution and refrigerant can be various. The most commonly used combination is that the solution is lithium bromide solution and the refrigerant is water. This embodiment is described as an example; the coupling device 3 is connected to the second heat pump 2 and forms a second evaporator 32 of the second heat pump 2. At this time, the second heat pump 2 includes a compressor 21, a second condenser 22 and a second evaporator 32. The second heat pump 2 is a vapor compression heat pump. The most commonly used refrigerant working fluids are R134a, R245fa, etc.

[0029] In the first heat pump 1, the first evaporator 11, the absorber 13, the generator 12 and the first condenser 31 are connected in sequence to form a loop. The first evaporator 11 and the generator 12 generate steam by absorbing the heat of the low-grade heat source introduced from the heat source inlet. The steam of the first evaporator 11 is introduced into the absorber 13, and the lithium bromide solution in the absorber 13 absorbs the steam to make the solution concentration thinner, and releases heat at the same time, heating the hot water introduced from the first hot water inlet 14 into hot water with a higher temperature, and discharges it from the first hot water outlet 15 for use. After the diluted lithium bromide solution is introduced into the generator 12, it evaporates due to endothermic evaporation, making the lithium bromide solution concentrated again, and the evaporated steam will be introduced into the first condenser 31 to release heat and condense to form liquid water. After the liquid water is introduced into the first evaporator 11 again, it can absorb the heat of the low-grade heat source again and evaporate, and participate in the cycle.

[0030] Although the figure does not show the connection between the first evaporator 11, the absorber 13, the generator 12 and the first condenser 31 and the refrigerant water circulation loop, how the various components of the second type absorption heat pump are connected is already a well-known prior art for those skilled in the art.

[0031] In the second heat pump 2, the second evaporator 32, the compressor 21 and the second condenser 22 are connected in sequence to form a refrigerant circuit. In the refrigerant circuit, the refrigerant flows from the second evaporator 32 to one side of the compressor 21. When passing through the second evaporator 32, the refrigerant liquid can absorb heat and evaporate to generate refrigerant vapor. Then, the vapor is compressed by passing through the compressor 21 to increase the temperature. When passing through the second condenser 22 again, the absorbed heat is released and liquefied. The liquefied refrigerant passes through the throttling device (not marked in the figure) and enters the second evaporator 32 again to absorb heat and evaporate. The cycle works in this way to continuously absorb heat from the second evaporator 32 and transfer the heat to the second condenser 22.

[0032] The second condenser 22 is provided with a second hot water inlet 23 and a second hot water outlet 24 . Therefore, the heat released at the second condenser 22 can heat the hot water introduced through the second hot water inlet 23 , and the heated hot water can be discharged through the second hot water outlet 24 .

[0033] The coupling device 3 can play the role of the first condenser 31 in the first heat pump 1 and participate in the refrigerant water circulation in the first heat pump 1. At the same time, the coupling device 3 can also play the role of the second evaporator 32 in the second heat pump 2 and participate in the refrigerant circulation. Through the setting of the coupling device 3, the first condenser 31 of the first heat pump 1 can provide heat for the second evaporator 32 of the second heat pump 2. While the refrigerant passing through the second evaporator 32 can evaporate, the water condensed by the first condenser 31 can reach a lower temperature, and the internal pressure of the first condenser 31 decreases. In this way, the generator 32 connected to the first condenser 31 can evaporate and concentrate the lithium bromide solution at a lower temperature, and can absorb more heat from the low-grade heat source. The first evaporator 11 also absorbs the heat from the low-grade heat source to evaporate the refrigerant (water), so that the low-grade heat source with a temperature in the range of 50°C to 70°C can be fully utilized to prepare hot water with a higher temperature, thereby solving the problem of recycling and utilizing a large number of low-grade heat sources with a temperature of 50°C to 70°C in the industrial field and improving the heat recovery efficiency.

[0034] In such Figure 2 In the second embodiment shown, the first hot water inlet 14 and the second hot water outlet 24 are connected, that is, the hot water discharged from the second hot water outlet 24 of the second heat pump 2 is not used directly, but is passed into the first hot water inlet 14 of the first heat pump 1, and is heated again by the first heat pump 1 to prepare hot water with a higher temperature.

[0035] Of course, in this embodiment, it can also be as follows Figure 1 In the first embodiment shown, the first hot water outlet 15 and the second hot water outlet 24 can respectively discharge hot water to the customer demand side, and the COP (heating performance coefficient) is high. The specific settings can be made according to actual conditions.

[0036] like Figure 1-Figure 4 As shown, the first heat source outlet 17 is connected to the second heat source inlet 18, that is, the first heat source inlet 16 and the second heat source inlet 18 are connected in series, so that the entire system has only one heat source inlet, namely the first heat source inlet 16. The low-grade heat source is introduced into the system through the first heat source inlet 16, and after supplying heat to the first evaporator 11, it can also supply heat to the generator 12; of course, in this embodiment, the first heat source inlet 16 and the second heat source inlet 18 can also be arranged in parallel.

[0037] like Figure 3 As shown, the hot water supply system also includes a first heat exchanger 4, and the second heat source outlet 19 of the generator 12 is also connected to the third heat source inlet 43 of the first heat exchanger 4. The first heat exchanger 4 includes a third hot water inlet 41 and a third hot water outlet 42, wherein the third hot water outlet 42 is connected to the second hot water inlet 23. That is to say, the low-grade heat source flows into the system from the first heat source inlet 16, and after providing heat to the first evaporator 11 and the generator 12, it is then introduced into the third heat source inlet 43 of the first heat exchanger 4 to provide heat to the first heat exchanger 4, and heat is exchanged with the hot water introduced into the first heat exchanger 4 from the third hot water inlet 41, so that the hot water is introduced into the second hot water inlet 23 from the third hot water outlet 42 after preliminary preheating. If the first hot water outlet 15 and the second hot water outlet 24 discharge hot water to the customer demand side respectively, the third hot water outlet 42 of the first heat exchanger 4 can be connected to the first hot water inlet 14, or to the second hot water inlet 23, or to the first hot water inlet 14 and the second hot water inlet 23 respectively.

[0038] After the low-grade heat source supplies heat to the first evaporator 11, the generator 12 and the first heat exchanger 4 in sequence, it is discharged from the third heat source outlet 44 of the first heat exchanger 4. After three levels of heating, the temperature of the water discharged from the third heat source outlet 44 is greatly reduced. Such an arrangement can further make full use of the heat of the low-grade heat source and improve the heat recovery efficiency.

[0039] In this embodiment, there is no limitation on the specific structure of the coupling device 3. Figure 1-Figure 3 In the three embodiments shown, the coupling device 3 is equivalent to a heat exchange device, which can simultaneously participate in the refrigerant water circulation in the first heat pump 1 and absorb the heat of the refrigerant water to reduce the temperature of the refrigerant water, and can also participate in the refrigerant circulation in the second heat pump 2, releasing heat to the refrigerant, causing the temperature of the refrigerant to increase and evaporate. Figure 4In the fourth embodiment shown, the coupling device 3 includes a first condenser 31, a second evaporator 32 and a circulation loop 33. The circulation loop 33 is connected between the first condenser 31 and the second evaporator 32, and a water pump 34 is connected in the circulation loop 33. Specifically, the medium flowing in the circulation loop 33 can be water or other heat-carrying fluids. When the medium flows through the first condenser 31, it can absorb the heat of the first condenser 31, and when it flows through the second evaporator 32, it can release the heat. The water pump 34 can provide power for the circulation of the medium in the circulation loop 33.

[0040] Further, such as Figure 4 As shown, the coupling device 3 also includes a second heat exchanger 35, which is connected between the first condenser 31 and the second evaporator 32. The medium in the circulation loop 33 can enter the second evaporator 32 from the first condenser 31 through the second heat exchanger 35, and the second heat source outlet 19 of the generator 12 is connected to the fourth heat source inlet 36 of the second heat exchanger 35. The low-grade heat source flows into the system from the first heat source inlet 16, and after providing heat to the first evaporator 11 and the generator 12, it is passed into the fourth heat source inlet 36 to provide heat to the second heat exchanger 35, so that the medium in the circulation loop 33 is heated. When the medium flows into the second evaporator 32, it can increase the evaporation amount of the refrigerant in the second evaporator 32, so that the water temperature of the second hot water outlet 24 of the second heat pump 2 is increased or more hot water is produced. After the low-grade heat source supplies heat to the first evaporator 11, the generator 12 and the second heat exchanger 35 in sequence, the heat is discharged from the fourth heat source outlet 37 of the second heat exchanger 35. After three levels of heating, the temperature of the water discharged from the fourth heat source outlet 37 is greatly reduced. This arrangement can further make full use of the heat of the low-grade heat source and improve the heat recovery efficiency.

[0041] like Figure 4 As shown, the circulation loop 33 is also connected to a water tank 38. The medium stored in the water tank 38 is the same as the medium flowing in the circulation loop 33. After passing through the second evaporator 32, the medium in the circulation loop 33 passes through the water tank 38 and flows through the first condenser 31. That is to say, when the medium reaches the first condenser 31 along the circulation loop 33, it passes through the water tank 38. Since more medium is stored in the water tank 38, the temperature of the medium flowing out of the water tank 38 is relatively stable, thereby making the temperature of the medium flowing through the first condenser 31 stable.

[0042] like Figure 1-Figure 4As shown, the second heat pump 2 also includes an economizer 25, which is connected to the compressor 21, the second condenser 22 and the second evaporator 32 respectively, and the compressor 21 is a two-stage compressor 21, the pressure in the economizer 25 is less than the pressure of the second condenser 22, and greater than the pressure of the second evaporator 32, the liquid refrigerant condensed in the second condenser 22 enters the economizer 25 through a throttling device (not marked in the figure), and a certain amount of steam is generated in the economizer 25, and then the refrigerant steam is passed into the compressor 21, and the liquid refrigerant enters the second evaporator 32 through a throttling device (not marked in the figure), and the setting of the economizer 25 can achieve the effect of energy saving. Specifically, the specific structure and principle of the economizer 25 are well-known prior art to those skilled in the art, and will not be repeated here to save space. Of course, in this embodiment, the second heat pump 2 can also be provided with no economizer 25, and a throttling component can be provided between the second condenser 22 and the second evaporator 32.

[0043] like Figure 1 and Figure 2 As shown, the hot water supply system also includes a flash tank 5, such as Figure 2 As shown, when the second hot water outlet 24 is connected to the first hot water inlet 14, the first hot water outlet 15 is connected to the flash tank 5, as shown in FIG. Figure 1 As shown, when the first hot water outlet 15 and the second hot water outlet 24 respectively discharge hot water to the customer demand side, the first hot water outlet 15 and the second hot water outlet 24 are respectively connected to the flash tank 5. After the hot water flowing out of the hot water outlet enters the flash tank 5, the steam can be discharged from the exhaust port 51 above, and the hot water can be discharged from the drain port 52 below, thereby satisfying the separation of steam and hot water to meet different usage requirements.

[0044] When only steam is needed without hot water, the drain port 52 of the flash tank 5 can be connected to the first hot water inlet 14 and / or the second hot water inlet 23 through a pipeline to allow the hot water to participate in the heating cycle again.

[0045] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A hot water supply system, characterized in that: It comprises a first heat pump (1), a second heat pump (2) and a coupling device (3); The first heat pump (1) comprises a first evaporator (11), a generator (12) and an absorber (13); the first evaporator (11) is provided with a first heat source inlet (16) and a first heat source outlet (17); the generator (12) is provided with a second heat source inlet (18) and a second heat source outlet (19); and the absorber (13) is provided with a first hot water inlet (14) and a first hot water outlet (15); The second heat pump (2) comprises a compressor (21) and a second condenser (22), the second condenser (22) being provided with a second hot water inlet (23) and a second hot water outlet (24); The coupling device (3) is connected to the first heat pump (1) and forms a first condenser (31) of the first heat pump (1), and the coupling device (3) is connected to the second heat pump (2) and forms a second evaporator (32) of the second heat pump (2); The first heat source outlet (17) is in communication with the second heat source inlet (18); The coupling device (3) comprises the first condenser (31), the second evaporator (32), and a circulation loop (33) connected between the first condenser (31) and the second evaporator (32); The coupling device (3) further comprises a second heat exchanger (35), the second heat exchanger (35) being connected between the first condenser (31) and the second evaporator (32), the water in the circulation loop (33) being able to enter the second evaporator (32) from the first condenser (31) through the second heat exchanger (35), and the second heat source outlet (19) being connected to a fourth heat source inlet (36) of the second heat exchanger (35).

2. The hot water supply system according to claim 1, characterized in that: The first hot water inlet (14) and the second hot water outlet (24) are in communication.

3. The hot water supply system according to claim 1 or 2, characterized in that: The invention also comprises a first heat exchanger (4), wherein the second heat source outlet (19) is connected to a third heat source inlet (43) of the first heat exchanger (4), and the first heat exchanger (4) further comprises a third hot water inlet (41) and a third hot water outlet (42), wherein the third hot water outlet (42) is connected to the first hot water inlet (14) and / or the second hot water inlet (23).

4. The hot water supply system according to claim 1 or 2, characterized in that: The circulation loop (33) is connected to a water pump (34).

5. The hot water supply system according to claim 1 or 2, characterized in that: The circulation loop (33) is also connected to a water tank (38), and the medium in the circulation loop (33) can flow from the second evaporator (32) through the water tank (38) and through the first condenser (31).

6. The hot water supply system according to claim 1 or 2, characterized in that: The second heat pump (2) further comprises an economizer (25), the economizer (25) being respectively connected to the compressor (21), the second condenser (22) and the second evaporator (32), and the compressor (21) is a two-stage compressor (21).

7. The hot water supply system according to claim 1 or 2, characterized in that: It also comprises a flash tank (5), wherein the flash tank (5) is in communication with the first hot water outlet (15).

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