Steam generation heat pump device

Abstract

To improve operational stability and allow for shorter piping. [Solution] A thermosiphon circuit is configured including a condenser (22) and a gas-liquid separator (31). Separated circulating water of the liquid phase separated by the gas-liquid separator and supply water supplied from a water supply pump (34) after heat exchange with the refrigerant in the subcooler (22) are combined at a confluence point (P1). A steam generation unit (11) boils the combined water in the condenser and supplies it to the gas-liquid separator. A heat pump unit (12) evaporates and compresses the refrigerant with heat recovered from the heat source water, and uses the refrigerant to boil the combined water in the condenser. The circulation channel (32) connected from the gas-liquid separator to the condenser includes a first piping section (41) connected to the gas-liquid separator and supplying separated circulating water, and a second piping section (42) connecting the first piping section and the condenser. The second piping section has a confluence point and extends along the horizontal direction.

Description

Technical Field

[0001] The present invention relates to a steam generation heat pump device, and particularly to a steam generation heat pump device having a thermosiphon circuit.

Background Art

[0002] Patent Document 1 discloses a steam generation heat pump device including a heat pump unit that recovers heat from heat source water, and a steam generation unit that exchanges heat with the refrigerant of the heat pump unit in a condenser. In the steam generation unit, the heated water supplied from an external water supply source is heated in the condenser to a gas-liquid two-phase state, and further separated into a gas phase portion and a liquid phase portion by a water vapor separator. Then, the separated liquid phase portion is returned to the condenser after merging with the heated water supplied from the external water supply source through a water supply passage, thereby circulating the heated water by the thermosiphon phenomenon.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, when the heated water from an external water supply source is higher than expected in temperature and the output steam temperature is low, the heated water boils before entering the condenser. In Patent Document 1, in order to prevent the circulation by the thermosiphon phenomenon from being inhibited by the bubbles rising through the pipeline due to boiling, a rising portion that goes upward toward the downstream is formed in the flow path from the water vapor separator to the condenser, and a water supply passage is connected to the rising portion. However, there is a problem that forming the rising portion increases the length of the pipe, increases the pressure loss, and increases the cost of the pipe.

[0005] This invention has been made in view of these circumstances, and aims to provide a steam generation heat pump device that can stabilize operation and shorten piping. [Means for solving the problem]

[0006] A steam generating heat pump device according to one embodiment of the present invention comprises a thermosiphon circuit including a condenser and a gas-liquid separator, a steam generating unit in which the liquid phase separated circulating water separated by the gas-liquid separator and supply water supplied from a water supply pump after heat exchange with a refrigerant in a preheating heat exchanger merge at a confluence point, the merged water is boiled in the condenser and supplied to the gas-liquid separator, and a heat pump unit in which the refrigerant is evaporated and compressed with heat recovered from the heat source water, and the merged water is boiled in the condenser by the refrigerant, the flow path connecting the gas-liquid separator to the condenser comprises a first piping section connected to the gas-liquid separator and supplying the separated circulating water, and a second piping section connecting the first piping section and the condenser, the second piping section having the confluence point and, In the entire length direction It is characterized by extending horizontally or along an inclined direction where the downstream side is slightly higher than the horizontal. [Effects of the Invention]

[0007] According to the present invention, since the second piping section including the confluence point follows the aforementioned extension direction, the formation of a rising section as in the conventional method can be eliminated, and the piping length can be shortened. Furthermore, even if the heated water flowing through the second piping section contains air bubbles, these bubbles can be directed to the condenser. This prevents the circulation from being obstructed by the thermosiphon effect due to the air bubbles rising up the pipeline, and stabilizes operation even when temperature conditions change. [Brief explanation of the drawing]

[0008] [Figure 1] This is a circuit diagram showing the configuration of a steam generation heat pump device according to an embodiment. [Figure 2] This figure shows the water circulation path of the steam generation heat pump system shown in Figure 1. [Figure 3] This diagram shows the water circulation path of a modified steam generation heat pump device. [Modes for carrying out the invention]

[0009] The steam generation heat pump device according to the embodiment will be described below with reference to the attached drawings. Note that the present invention is not limited to the embodiments described below, and can be modified as appropriate without changing its essence. In the following figures, some components may be omitted for the sake of explanation.

[0010] Figure 1 is a circuit diagram showing the configuration of a steam generation heat pump device according to an embodiment. The steam generation heat pump device 10 is a device that recovers waste heat from waste hot water (heat source water) such as factory wastewater and generates steam using the recovered waste heat. The generated steam is sent to external steam utilization equipment such as drying equipment and sterilization equipment.

[0011] As shown in Figure 1, the steam generation heat pump device 10 has a heat pump unit 11 and a steam generation unit 12. The steam generation unit 12 heats the water to be heated using the heat source generated by the heat pump unit 11 and generates steam.

[0012] The heat pump unit 11 is a device having a heat pump cycle in which a compressor 25 for compressing a refrigerant, a condenser 21 for condensing the refrigerant compressed by the compressor 25, a subcooler 22 (preheating heat exchanger) for further cooling the liquid refrigerant condensed in the condenser 21, an expansion valve 23 for reducing the pressure of the refrigerant from the subcooler 22, and an evaporator 24 that recovers heat from waste hot water, evaporates the refrigerant from the expansion valve 23, and flows out to the compressor 25 are connected in a ring shape.

[0013] The refrigerant, compressed to high temperature and pressure by the compressor 25, is cooled and condensed in the condenser 21 by heat exchange with the heated water circulating in the steam generation unit 12 and the supply water supplied by the water supply pump 34. The refrigerant discharged from the condenser 21 is supercooled in the subcooler 22 by preheating the heated water. The supercooled refrigerant in the subcooler 22 is adiabatically expanded in the expansion valve 23, evaporates in the evaporator 24 by absorbing heat from the waste hot water, and is then discharged to the compressor 25.

[0014] The steam generation unit 12 includes a condenser 21 that generates steam by evaporating water using a refrigerant circulating in the heat pump unit 11 as a heat source, and a gas-liquid separator 31 that separates the heated water, which is a two-phase gas-liquid flow containing the water and steam generated by the condenser 21, into steam and water. Therefore, the steam generation unit 12 shares the condenser 21 with the heat pump unit 11. The gas-liquid separator 31 is, for example, composed of a cylindrical container oriented vertically.

[0015] Furthermore, the steam generation unit 12 has a circulation channel 32 (channel) that guides the heated water separated by the gas-liquid separator 31 from the condenser 21 to the gas-liquid separator 31 and circulates it. One end of the circulation channel 32 is connected to the lower end of the gas-liquid separator 31, and the other end is connected to the upper circumferential surface of the gas-liquid separator 31. A feedwater channel 33 is connected to the circulation channel 32 at a confluence point P1, and the feedwater supplied from the feedwater pump 34 through the feedwater channel 33 and the heated water in the liquid phase separated by the gas-liquid separator 31 are combined at the confluence point P1. A blowdown water channel 35 may be connected to a separation point P2 on the circulation channel 32 from the lower end wall of the gas-liquid separator 31 to the confluence point P1, to extract a portion of the heated water in the liquid phase separated by the gas-liquid separator 31 and discharge this extracted hot water as blowdown water.

[0016] Furthermore, a heat recovery unit 36 ​​is provided to perform heat exchange between the supply water in the supply water channel 33 between the feedwater pump 34 and the supercooler 22 and the blowdown water in the blowdown water channel 35. The heat recovery unit 36 ​​performs heat exchange between the blowdown water and the supply water, recovering the heat from the blowdown water into the supply water. The heat-recovered supply water is preheated in the supercooler 22 via a check valve 37, and the preheated supply water merges with the water to be heated at the confluence point P1 and is led to the condenser 21. A flow rate control valve 38 is placed in the blowdown water channel 35 between the separation point P2 and the heat recovery unit 36.

[0017] Furthermore, the steam generation unit 12 has a steam flow path 39 that supplies the steam separated in the gas-liquid separator 31 to external steam utilization equipment. The steam flow path 39 is connected to the upper end wall of the gas-liquid separator 31 and is a flow path that sends the steam (gas-phase heated water) to the outside after the liquid-phase heated water has been separated in the gas-liquid separator 31. A steam pressure regulating valve 39a is installed in the steam flow path 39 to adjust the pressure of the flowing steam. The opening degree of the steam pressure regulating valve 39a is adjusted based on the steam pressure inside the gas-liquid separator 31, which is measured by a pressure sensor (not shown).

[0018] Figure 2 shows the water circulation path of the steam generation heat pump system shown in Figure 1. In Figure 2, the dashed lines indicate the refrigerant pipeline, and the other solid lines indicate the water circulation path. The same applies to Figure 3.

[0019] As shown in Figure 2, in the steam generation unit 12, a supercooler 22 is shared with the heat pump unit 11 (see Figure 1) in addition to the condenser 21. The supercooler 22 is positioned above the condenser 21 via a support member (not shown). For example, the condenser 21 is installed on a foundation, and at least a portion of the condenser 21 and the supercooler 22 are arranged to overlap each other vertically.

[0020] The steam generation unit 12 includes the condenser 21, subcooler 22, gas-liquid separator 31, circulation flow path 32, water supply flow path 33, and water supply pump 34 described above. In the steam generation unit 12, the supply water supplied from the water supply pump 34 is heat-exchanged with the refrigerant in the subcooler 22, whereby the supply water is preheated in the subcooler 22 and then supplied to the condenser 21. In the condenser 21, the water to be heated is boiled by heat-exchanging with the refrigerant.

[0021] The water to be heated boiled in the condenser 21 is supplied to the gas-liquid separator 31 and separated into a gas phase (steam) and a liquid phase (hot water). Among the liquid phase separated by the gas-liquid separator 31, the portion excluding the blowdown water is joined at the junction point P1 of the circulation flow path 32 as the separated circulating water of the liquid phase with the supply water from the water supply pump 34 and the water supply flow path 33, and then supplied to the condenser 21. The water to be heated is circulated between the condenser 21 and the gas-liquid separator 31, and a thermosyphon circuit including the condenser 21, gas-liquid separator 31, and circulation flow path 32 is formed.

[0022] The circulation flow path 32 connected from the liquid phase outlet 31a of the gas-liquid separator 31 to the water inlet 21a of the condenser 21 includes a first pipe portion 41 and a second pipe portion 42.

[0023] The upper end (one end) of the first pipe portion 41 is connected to the liquid phase outlet 31a provided on the lower wall of the gas-liquid separator 31, and sends out the separated circulating water of the liquid phase separated by the gas-liquid separator 31. The first pipe portion 41 extends along the vertical direction between the gas-liquid separator 31 and the second pipe portion 42.

[0024] The second pipe portion 42 connects the lower end (the other end) of the first pipe portion 41 and the water inlet 21a of the condenser 21. In the present embodiment, the second pipe portion 42 extends along the horizontal direction in all of the length direction, the upstream end 42a which becomes the left end in FIG. 2 is connected to the lower end of the first pipe portion 41, and the downstream end 42b which becomes the right end in FIG. 2 is connected to the water inlet 21a of the condenser 21. In other words, the vertical positions of the lower end of the first pipe portion 41 and the water inlet 21a of the condenser 21 are set to be substantially the same, and the second pipe portion 42 linearly connects between them.

[0025] The second piping section 42 includes a confluence point P1, which is the downstream end of the water supply channel 33. At the confluence point P1, the liquid phase separated circulating water, which is separated in the gas-liquid separator 31 and sent from the first piping section 41 to the second piping section 42, and the heated water (supply water) supplied from the water supply pump 34, which undergoes heat exchange with the refrigerant in the subcooler 22 as it passes through the water supply channel 33, are combined. In the steam generation section 12, the combined water generated by this confluence is boiled in the condenser 21 and supplied to the gas-liquid separator 31.

[0026] According to the above embodiment, when the supply water preheated in the subcooler 22 boils and contains bubbles, the bubbles reach the second piping section 42 in the circulation channel 32 from the confluence point P1. Because the second piping section 42 extends horizontally, the bubbles themselves cannot move from the confluence point P1 to either the upstream end 42a or the downstream end 42b of the second piping section 42 by buoyancy alone. Therefore, the bubbles that reach the second piping section 42 move in the circulation direction of the heated water and flow into the condenser 21. This prevents the bubbles that reach the second piping section 42 from flowing back against the circulation direction of the heated water in the circulation channel 32, and suppresses the bubbles from obstructing the circulation of the thermosiphon circuit.

[0027] Therefore, even under operating conditions where the feedwater preheated in the supercooler 22 boils and bubbles are generated, the steam generation heat pump system 10 can be operated stably without being affected. Thus, the steam generation heat pump system 10 can substantially eliminate the upper limit on the temperature of the feedwater supplied through the confluence point P1, and the limitations on the sites in which it can be applied can be relaxed.

[0028] Furthermore, since the second piping section 42 extends horizontally, the lower end of the first piping section 41 and the water inlet 21a of the condenser 21 can be connected at the shortest distance while maintaining the same height. As a result, compared to conventional structures where the second piping section has a portion extending vertically, the length of the second piping section 42 can be shortened, reducing pressure loss in the second piping section 42, improving the circulation efficiency of the heated water, and enhancing the steam generation efficiency. Moreover, by shortening the length of the second piping section 42, the costs required for materials and installation work of the second piping section 42 can be reduced.

[0029] Furthermore, the length between the downstream end 42b of the second piping section 42 and the confluence point P1 may be set shorter than the length between the upstream end 42a of the second piping section 42 and the confluence point P1, thereby shortening the length of the second piping section 42 between the confluence point P1 and the condenser 21. This makes it easier for bubbles in the second piping section 42 to move in the direction of circulation of the heated water, and better prevents bubbles from flowing back in the direction of circulation of the heated water.

[0030] Furthermore, since the supercooler 22 is positioned above the condenser 21, and at least a portion of the condenser 21 and the supercooler 22 overlap each other vertically, the installation space can be reduced compared to the case where both the condenser 21 and the supercooler 22 are placed on a foundation.

[0031] It should be noted that the present invention is not limited to the embodiments described above, and can be implemented with various modifications. In the embodiments described above, the size, shape, orientation, etc., shown in the accompanying drawings are not limited thereto, and can be appropriately modified within the scope that allows the present invention to exert its effects. Furthermore, it can be implemented with appropriate modifications as long as it does not deviate from the scope of the objectives of the present invention.

[0032] For example, as shown in the modified example in Figure 3, the condenser 21 and the subcooler 22 may be arranged in different positions horizontally without overlapping vertically.

[0033] Furthermore, the diameters of the first piping section 41 and the second piping section 42 are designed according to the temperature of the steam output by the steam generation heat pump device 10. Therefore, for example, the first piping section 41 and the second piping section 42 may have the same diameter, or they may be made to be different in diameter, with the first piping section 41 having a larger diameter than the second piping section 42.

[0034] Furthermore, in addition to extending horizontally as in the above embodiment, the second piping section 42 may also be configured to extend along an inclined direction where the downstream end 42b is slightly higher than the horizontal end. This configuration also prevents bubbles that reach the second piping section 42 from flowing back against the circulation direction of the heated water in the circulation channel 32, and also prevents the second piping section 42 from becoming excessively long. [Explanation of Symbols]

[0035] 10: Steam generation heat pump device 11: Heat pump section 12: Steam generation unit 21: Condenser 22: Supercooler (heat exchanger for preheating) 31: Gas-liquid separator 32: Circulation channel (channel) 34: Water supply pump 41: Piping Section 1 42: Second Piping Section 42a: Upstream end 42b: Downstream end P1: Confluence point

Claims

1. A thermosiphon circuit including a condenser and a gas-liquid separator is configured, and the separated liquid phase circulating water separated by the gas-liquid separator and the supply water supplied from the water supply pump after heat exchange with the refrigerant in a preheating heat exchanger merge at a confluence point, and the combined water is boiled in the condenser and supplied to the gas-liquid separator in the steam generation unit, The system comprises a heat pump unit that evaporates and compresses the refrigerant using heat recovered from the heat source water, and uses the refrigerant to boil the combined water in the condenser, The flow path connecting the gas-liquid separator to the condenser is, A first piping section connected to the gas-liquid separator and for discharging the separated circulating water, The system comprises a second piping section connecting the first piping section and the condenser, The steam generating heat pump device is characterized in that the second piping section has the aforementioned confluence point and extends along the entire length in a horizontal direction or in an inclined direction where the downstream side is slightly higher than the horizontal direction.

2. The steam generating heat pump apparatus according to claim 1, characterized in that the preheating heat exchanger is positioned above the condenser, and at least a portion of the condenser and the preheating heat exchanger are arranged to overlap each other vertically.

3. The steam generating heat pump apparatus according to claim 1, characterized in that the first piping section extends vertically between the gas-liquid separator and the second piping section.

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