Steam generation system and steam generation method

Abstract

Provided is a steam generation system capable of generating steam with high thermal efficiency even when an intermediate fluid for transferring heat from a heat pump to a steam generator is used. A steam generation system (1A) comprises: a heat pump (3) provided with a compressor (12) for compressing a refrigerant, a condenser (13) for condensing the refrigerant compressed by the compressor (12), an expansion valve (14) for decompressing the refrigerant condensed by the condenser (13), and an evaporator (15) for evaporating the refrigerant expanded by the expansion valve (14); a steam generator (7) for exchanging heat between water, which is an intermediate fluid, and feedwater and then generating steam from the water; and an intermediate fluid circulation flow path (5) for circulating the water, which is the intermediate fluid, between the condenser (13) and the steam generator (7). The pressure of the water which is the intermediate fluid is higher than that of the steam generated by the steam generator (7).

Description

Steam generation system and steam generation method

[0001] The present disclosure relates to a steam generating system and a method for generating steam.

[0002] It is known that water is heated by a heat pump using hot wastewater or air as a heat source to generate steam in order to supply steam to various processes in factories. For example, a heat pump steam generator disclosed in Patent Document 1 is configured to include a fluid heat transfer section in which an intermediate fluid circulates between a condenser of the heat pump and a steam generator. Water is heated in the steam generator by the intermediate fluid circulating through the fluid heat transfer section, generating steam. A hydrofluorocarbon with a relatively high boiling point is used as the intermediate fluid circulating through the fluid heat transfer section.

[0003] The heat pump steam generator of Patent Document 1 is operated so that the pressure of the intermediate fluid is lower than the pressure of the steam in the steam generator, in order to prevent the intermediate fluid from mixing with the steam in the steam generator even if the steam generator is damaged.

[0004] JP 2012-37197 A

[0005] However, if the pressure of the intermediate fluid circulating through the fluid heat transfer section is made lower than that of the steam as in Patent Document 1, there is a risk that a sufficient amount of heat cannot be transported from the heat pump to the steam generator via the intermediate fluid.

[0006] In particular, when negative pressure steam is generated in a steam generator by heating water at a low temperature below 100° C., the pressure of the intermediate fluid becomes even lower, resulting in a decrease in thermal efficiency.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a steam generation system and a steam generation method that can generate steam with high thermal efficiency even when using an intermediate fluid that transfers heat from a heat pump to a steam generator.

[0008] A steam generation system according to one aspect of the present disclosure includes a heat pump having a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that reduces the pressure of the refrigerant condensed by the condenser, and an evaporator that evaporates the refrigerant expanded by the expansion valve, a steam generator that generates steam from water by heat exchange between an intermediate fluid and the water, and an intermediate fluid circulation flow path through which the intermediate fluid circulates between the condenser and the steam generator, wherein the intermediate fluid has a higher pressure than the steam generated by the steam generator.

[0009] A steam generation method according to one aspect of the present disclosure is a steam generation method using a steam generation system including: a heat pump having a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that decompresses the refrigerant condensed by the condenser, and an evaporator that evaporates the refrigerant expanded by the expansion valve; a steam generator that generates steam by heat exchange between an intermediate fluid and water; and an intermediate fluid circulation flow path through which the intermediate fluid circulates between the condenser and the steam generator, wherein the intermediate fluid has a higher pressure than the steam generated by the steam generator.

[0010] Even when an intermediate fluid is used to transfer heat from the heat pump to the steam generator, steam can be generated with high thermal efficiency.

[0011] Fig. 1 is a schematic configuration diagram showing a steam generating system according to a first embodiment of the present disclosure. Fig. 2 is a schematic configuration diagram showing a modified example of the first embodiment. Fig. 3 is a schematic configuration diagram showing a reference example corresponding to Fig. 2. Fig. 4 is a schematic configuration diagram showing a steam generating system according to a second embodiment of the present disclosure. Fig. 5 is a schematic configuration diagram showing a modified example of the second embodiment. Fig. 6 is a schematic configuration diagram showing another modified example of the second embodiment.

[0012] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. [First Embodiment] Hereinafter, a first embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 discloses a steam generation system 1A according to this embodiment. The steam generation system 1A includes a heat pump 3, an intermediate fluid circulation passage 5, and a steam generator 7.

[0013] The heat pump 3 includes a refrigerant circulation path 11 that circulates a refrigerant. The refrigerant circulation path 11 includes a compressor 12 that compresses the refrigerant, a condenser 13 that condenses the refrigerant compressed by the compressor 12, an expansion valve 14 that reduces the pressure of the refrigerant condensed by the condenser 13, and an evaporator 15 that evaporates the refrigerant expanded by the expansion valve 14.

[0014] The compressor 12 may be a positive displacement compressor such as a scroll compressor or a rotary compressor, or a turbo compressor. The refrigerant may be a fluorocarbon substitute refrigerant such as HFC or HCFC, or a natural refrigerant such as a hydrocarbon or CO2. The operation of the compressor 12 is controlled by a control unit (not shown).

[0015] The heat source medium introduced into the evaporator 15 is heat source water, which is water at atmospheric pressure. For example, hot wastewater at about 40°C to 60°C can be used as the heat source water. Air (outside air) can also be used as the heat source medium instead of water. The refrigerant absorbs heat from the heat source water as it evaporates in the evaporator 15. A non-contact heat exchanger that exchanges heat between the heat source water and the refrigerant without contact is used as the evaporator 15, and for example, a partition wall heat exchanger such as a plate heat exchanger, a shell-and-plate heat exchanger, or a shell-and-tube heat exchanger can be used.

[0016] The condenser 13 exchanges heat with water (intermediate fluid: hereinafter referred to as "intermediate water") flowing through the intermediate fluid circulation flow path 5. The condenser 13 transfers the latent heat of condensation of the refrigerant to the intermediate water, thereby heating the intermediate water. The intermediate water is heated by the condenser 13 to, for example, about 90°C to about 100°C. A non-contact heat exchanger that exchanges heat between the intermediate water and the refrigerant without contacting each other is used as the condenser 13, and for example, a partition-type heat exchanger such as a plate heat exchanger, a shell-and-plate heat exchanger, or a shell-and-tube heat exchanger can be used.

[0017] The expansion valve 14 throttles and expands the liquid refrigerant guided from the condenser 13. The opening degree of the expansion valve 14 is controlled by a control unit (not shown).

[0018] The intermediate fluid circulation flow path 5 is a closed-loop flow path for circulating intermediate water. The intermediate water circulates in a liquid phase throughout the entire intermediate fluid circulation flow path 5 (except for local boiling that occurs near the heat transfer surface of the condenser 13, etc.). A water pump 17 is provided in the intermediate fluid circulation flow path 5. The operation of the water pump 17 is controlled by a control unit (not shown). Note that the intermediate water is not limited to pure water, and any water containing water as the main fluid may be used. For example, the intermediate water may contain additives such as agents for rust prevention, antiseptic effects, or antifreeze effects, or colorants.

[0019] The steam generator 7 is a non-contact heat exchanger in which heat is exchanged between the intermediate water and the feed water without contact, and a partition-type heat exchanger such as a plate-type heat exchanger, a shell-and-plate heat exchanger, or a shell-and-tube heat exchanger can be used.

[0020] A feedwater flow path 30 that supplies feedwater to be heated is connected to the steam generator 7. A pressure reducing valve 32 is provided in the feedwater flow path 30. The pressure reducing valve 32 works in cooperation with a steam compressor 35 (described later) to reduce the pressure of feedwater that has been brought to atmospheric pressure at room temperature (e.g., 20°C) to produce negative pressure water. The opening of the pressure reducing valve 32 is controlled by a control unit (not shown) in coordination with the operation of the compressor as necessary.

[0021] A steam supply line 34 is connected to the steam generator 7, through which the negative pressure steam generated by the steam generator 7 flows. The negative pressure steam generated by the steam generator 7 is generated by intermediate water whose temperature is lower than 100°C. For example, when the pressure of the feed water is -0.054 MPaG, saturated steam is at 80°C, so negative pressure steam can be generated with intermediate water at about 85°C.

[0022] The steam supply path 34 is provided with a steam compressor 35 and a supply amount adjustment unit 36. The steam compressor 35 compresses the negative pressure steam to a pressure equal to or higher than atmospheric pressure. As the steam compressor 35, for example, a positive displacement compressor such as a screw compressor or a claw compressor, or a turbo compressor, may be used. Furthermore, operation of the steam compressor 35 reduces the pressure in the flow path ranging from its upstream side to the downstream side of the pressure reducing valve 32. The supply amount adjustment unit 36 ​​separates the pressurized steam into gas and liquid and adjusts the amount of steam introduced to the steam user side.

[0023] A portion of the feed water is guided to the supply amount adjustment unit 36 ​​from the feed water flow path 30 via a water injection pipe 37. The steam guided to the supply amount adjustment unit 36 ​​is cooled by the injection of the feed water guided from the water injection pipe 37. The water injection pipe 37 may be provided in the steam compressor 35 or in the steam supply path 34 upstream of the steam compressor 35. The water injection pipe 37 may be provided with a pressure boosting means (such as a pump) to obtain the pressure required for injection.

[0024] The control unit is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium, for example, in the form of a program. The CPU reads this program into RAM and executes information processing and arithmetic operations to realize various functions. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0025] The steam generation system 1A described above operates as follows. The heat pump 3 absorbs heat from the heat source water in the evaporator 15 and releases heat of condensation in the condenser 13. In the condenser 13, the intermediate water is heated by the heat of condensation obtained from the heat pump 3. The intermediate water is at atmospheric pressure, so its saturated steam temperature is 100°C. This allows the condenser 13 to receive sensible heat of a temperature (e.g., 85°C) sufficient to evaporate the negative pressure water. Note that the term "atmospheric pressure" mentioned above also includes a state in which the pressure value deviates from the accurate atmospheric pressure depending on the measurement location due to local pressure increase or decrease caused by pressure loss or resistance in the intermediate fluid circulation flow path 5 during operation. When operation is stopped, the pressure as a whole is substantially equal to atmospheric pressure.

[0026] The intermediate water heated in the condenser 13 is guided to the steam generator 7 through the intermediate fluid circulation flow path 5, and heats the feed water guided from the feed water flow path 30. The feed water is depressurized to a negative pressure by the pressure reducing valve 32, and therefore evaporates at a temperature below 100°C (for example, 80°C) to become negative pressure steam.

[0027] The negative pressure steam generated by the steam generator 7 passes through a steam supply line 34 and is pressurized to a pressure equal to or higher than atmospheric pressure by a steam compressor 35. The pressurized steam is cooled by water injected from a water injection pipe 37 in a supply amount adjustment unit 36, and after gas-liquid separation, is supplied to the user side.

[0028] The effects of the present embodiment described above are as follows: The pressure of the water, which is the intermediate fluid, is atmospheric pressure, which is higher than the pressure of the negative pressure steam generated in the steam generator 7, so that the intermediate water can transport sufficient thermal energy from the condenser 13 of the heat pump 3 to the steam generator 7. This can improve the thermal efficiency of the steam generation system 1A.

[0029] The pressure reducing valve 32 reduces the pressure of the feedwater below atmospheric pressure to generate negative pressure water, which is then supplied to the steam generator 7. This allows the steam generator 7 to generate negative pressure steam by heating intermediate water below 100°C. As this produces intermediate water below 100°C, it is possible to use relatively low-temperature exhaust heat or air as the heat source water to be absorbed by the evaporator 15 of the heat pump 3.

[0030] <Modification 1> The intermediate water may be pressurized to atmospheric pressure or higher (for example, 0.3 MPaG). One means for pressurizing water is illustrated in Fig. 2. As shown in the figure, a pressure regulator 20 is provided in the intermediate fluid circulation flow path 5. The pressure regulator 20 may be provided in any of the flow paths of the intermediate fluid circulation flow path 5.

[0031] The pressure adjusting device 20 includes a container capable of storing a predetermined amount of water, one end of which is connected to the intermediate fluid circulation flow path 5, and the other end of which is connected to the discharge side of the compression pump 22. The compression pump 22 is a pump that compresses gas such as air, and the discharge pressure is adjusted by a control unit. The pressure of the intermediate water is set by the gas pressurized by the compression pump 22.

[0032] By setting the pressure in the intermediate fluid circulation flow path 5 to atmospheric pressure or higher, the saturation temperature of the intermediate water can be increased (for example, the saturation temperature is 143°C at 0.3 MPaG). This allows the temperature of the refrigerant supplied to the condenser 13 to be as high as 100°C or higher, thereby increasing the amount of heat transport by the intermediate water. In this case, the steam generator 7 can heat the feed water to a temperature of 100°C or higher.

[0033] The pressure adjusting device 20 is not limited to a type that uses the compression pump 22, and may be any device that can pressurize the intermediate fluid circulation flow path 5. For example, it may be a device that pressurizes the intermediate water in the container using a piston.

[0034] For example, if water, which is the intermediate fluid, is used at atmospheric pressure without being pressurized, the saturation temperature of water is 100°C, and therefore, as shown in Figure 3, the intermediate water will boil due to heating of the refrigerant, and a gas phase will be generated in the intermediate fluid circulation flow path 5, which will hinder smooth circulation of the intermediate water and may reduce the heat transport capacity of the intermediate water.

[0035] In contrast, in the present modification shown in FIG. 2 , the intermediate water is kept at atmospheric pressure or higher, thereby minimizing the evaporation of water in the condenser 13 to form a gas phase. This increases the amount of heat transport from the condenser 13 of the heat pump 3 to the steam generator 7. Even when pressurized, the temperature of the intermediate water can be maintained near its boiling point at atmospheric pressure. Furthermore, even when pressurized, maintaining the temperature of the intermediate water below its boiling point at atmospheric pressure reduces the temperature rise even in an operating environment where the heat source temperature of the heat pump 3 is relatively low. This maintains the COP value of the heat pump relatively high, and more effectively prevents the intermediate water from boiling. Furthermore, instead of intermediate water, brine (antifreeze) primarily composed of glycols such as ethylene glycol can be used as the intermediate fluid. Because brine has a boiling point slightly higher than 100°C, it can further suppress the boiling. Similarly to the intermediate water, brine can be pressurized for use. Even when pressurized, the brine temperature can be maintained near its boiling point at atmospheric pressure. Furthermore, even when the brine is used under pressure, by setting the temperature of the brine below its boiling point under atmospheric pressure, the temperature rise can be reduced even in an operating environment where the heat source temperature of the heat pump 3 is relatively low, and the COP value of the heat pump can be maintained relatively high.

[0036] Second Embodiment Next, a second embodiment of the present disclosure will be described with reference to Fig. 4. A steam generating system 1B according to this embodiment is similar to the first embodiment shown in Fig. 1 except that the intermediate fluid is changed from water to a heat medium that undergoes a phase change. Therefore, the following description will focus on the differences, and the same reference numerals will be used to designate common components, and their description will be omitted.

[0037] 4, a phase-change heat transfer medium circulates in the intermediate fluid circulation flow path 5′ of the steam generation system 1B according to this embodiment. The heat transfer medium is sealed in the intermediate fluid circulation flow path 5′ at a pressure equal to or higher than atmospheric pressure and circulated by a heat transfer medium pump 18.

[0038] The heat medium evaporates in the condenser 13 and condenses in the steam generator 7. As the heat medium, for example, neopentane can be used. When neopentane is used, it undergoes a phase change at 85° C. at a pressure of 0.72 MPaG.

[0039] In addition to the effects of the first embodiment described above, the present embodiment has the following advantages: By using a fluid that evaporates in the condenser 13 and condenses in the steam generator 7 as the intermediate fluid, it is possible to utilize the latent heat generated during the phase change. This increases the amount of heat transport from the condenser 13 of the heat pump 3 to the steam generator 7.

[0040] <Modification 2> This embodiment can be modified as shown in Fig. 5. Fig. 5 shows the intermediate fluid circulation passage 5, condenser 13, and steam generator 7 shown in Fig. 4. As shown in the figure, the steam generator 7 is provided at a higher position than the condenser 13. Preferably, the lower end of the heat transfer section of the steam generator 7 is positioned higher than the upper end of the heat transfer section of the condenser 13. Here, the heat transfer section means the portion where heat exchange takes place, and specifically means the region where heat transfer tubes and the like are present.

[0041] By providing the steam generator 7 at a higher position than the condenser 13 in this way, a head difference can be created between the liquid level of the heat medium (intermediate fluid) in the steam generator 7 and the liquid level of the heat medium (intermediate fluid) in the condenser 13. This provides a driving force for circulating the heat medium, allowing the power of the heat medium pump 18 to be reduced or the pump itself to be made smaller.

[0042] As shown in FIG. 5, when a sufficient head difference is provided, a sufficient driving force for circulating the heat medium can be obtained, so that the heat medium pump 18 (see FIG. 4) can be omitted.

[0043] <Modification 3> Alternatively, a modification can be made as shown in Fig. 6. Fig. 6 shows the intermediate fluid circulation passage 5, the condenser 13, the steam generator 7, and the heat medium pump 18 shown in Fig. 4.

[0044] In this modification, the liquid level L1 of the heat medium (intermediate fluid) in the steam generator 7 is controlled to be higher than the liquid level L2 of the heat medium in the condenser 13. Specifically, the flow rate of the heat medium pump 18 is controlled by the control unit to adjust the heat exchange amount in the condenser 13 and the steam generator 7, and the liquid levels L1, L2 are controlled to provide the head difference. For example, the head difference can be adjusted by increasing the circulation flow rate by controlling the rotation speed of the heat medium pump 18 to raise the liquid level L2 of the heat medium in the condenser 13. Note that when adjusting the head difference, level sensors that detect the liquid levels L1, L2 of the heat medium may be provided in the steam generator 7 and the condenser 13 for control.

[0045] In this way, a driving force for circulating the heat medium can be provided by creating a head difference between the liquid level L1 of the heat medium in the steam generator 7 and the liquid level L2 of the heat medium in the condenser 13. As a result, even if there are physical restrictions in the vertical direction for the space occupied by the entire system, the same effect as in <Modification 2> can be obtained.

[0046] The steam generating system and the steam generating method described in each of the above-described embodiments can be understood, for example, as follows.

[0047] The steam generation system according to a first aspect of the present disclosure comprises a heat pump (3) having a compressor (12) that compresses a refrigerant, a condenser (13) in which the refrigerant compressed by the compressor is condensed, an expansion valve (14) that reduces the pressure of the refrigerant condensed by the condenser, and an evaporator (15) in which the refrigerant expanded by the expansion valve is evaporated; a steam generator (7) that performs heat exchange between an intermediate fluid and water to generate steam from the water; and an intermediate fluid circulation flow path (5) in which the intermediate fluid circulates between the condenser and the steam generator, wherein the intermediate fluid has a higher pressure than the steam generated by the steam generator.

[0048] Since the pressure of the intermediate fluid is set higher than the pressure of the steam generated by the steam generator, sufficient thermal energy can be transported from the condenser of the heat pump to the steam generator by the intermediate fluid, thereby improving the thermal efficiency of the steam generation system.

[0049] A steam generating system according to a second aspect of the present disclosure is the above-mentioned first aspect, further including a pressure reducing valve (32) that reduces the pressure of water to be supplied to the steam generator to a pressure lower than atmospheric pressure.

[0050] The pressure reducing valve reduces the pressure of water below atmospheric pressure to generate negative pressure water, which is then supplied to the steam generator. This allows the steam generator to generate negative pressure steam by heating it with an intermediate fluid below 100°C. Since the intermediate fluid is below 100°C, relatively low-temperature exhaust heat or air can be used as the heat source to be absorbed by the evaporator of the heat pump.

[0051] A steam generating system according to a third aspect of the present disclosure is the steam generating system of the first or second aspect, wherein the intermediate fluid is at atmospheric pressure or higher.

[0052] Since the intermediate fluid is at atmospheric pressure or higher, the amount of heat transport from the condenser to the steam generator of the heat pump can be increased.

[0053] A fourth aspect of the present disclosure relates to a steam generation system according to any one of the first to third aspects, wherein the intermediate fluid is water or brine that circulates in a liquid phase through the intermediate fluid circulation flow path.

[0054] Since the intermediate fluid circulates in the liquid phase through the intermediate fluid circulation channel, no gas phase is generated in the intermediate fluid circulation channel, and heat transfer is not hindered. Note that the water is not limited to pure water, and any other fluid may be used as long as it is mainly water, for example, water to which antifreeze has been added.

[0055] A steam generating system according to a fifth aspect of the present disclosure is the steam generating system of any one of the first to fourth aspects, further comprising a pressurizing means for pressurizing the intermediate fluid circulating through the intermediate fluid circulation channel to a pressure equal to or higher than atmospheric pressure.

[0056] By pressurizing the intermediate fluid circulating through the intermediate fluid circulation passage to atmospheric pressure or higher, the saturation temperature of the intermediate fluid can be increased, which makes it possible to prevent the intermediate fluid from evaporating when heated in the condenser of the heat pump. As a result, no gas phase is generated in the intermediate fluid circulation passage, and heat transport is not hindered.

[0057] A steam generation system according to a sixth aspect of the present disclosure is any one of the first to third aspects, wherein the intermediate fluid is a fluid that evaporates in the condenser and condenses in the steam generator.

[0058] By using a fluid that evaporates in the condenser and condenses in the vapor generator as the intermediate fluid, the latent heat generated during the phase change can be utilized. This increases the amount of heat transport from the condenser to the vapor generator of the heat pump. For example, neopentane can be used as the intermediate fluid.

[0059] A seventh aspect of the present disclosure provides a steam generating system according to the sixth aspect, wherein the steam generator is provided at a higher position than the condenser.

[0060] Since the steam generator is provided at a higher position than the condenser, a head difference can be created between the liquid level of the intermediate fluid in the steam generator and the liquid level of the intermediate fluid in the condenser. This can provide a driving force for circulating the intermediate fluid. If a sufficient driving force for circulating the intermediate fluid can be obtained, the intermediate pump for circulating the intermediate fluid can be eliminated.

[0061] The steam generating system according to an eighth aspect of the present disclosure is the sixth aspect, further comprising a control means for making the liquid level of the intermediate fluid in the steam generator higher than the liquid level of the intermediate fluid in the condenser.

[0062] A head difference can be created by making the liquid level of the intermediate fluid in the steam generator higher than the liquid level of the intermediate fluid in the condenser. This provides a driving force for circulating the intermediate fluid. Examples of control means for creating the head difference include a circulation pump that circulates the intermediate fluid and a control unit for controlling the flow rate of the circulation pump. By controlling the circulation flow rate, the amount of heat exchange in the condenser and the steam generator can be adjusted, thereby creating a head difference.

[0063] A steam generation method according to a first aspect of the present disclosure is a steam generation method using a steam generation system including: a heat pump having a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that decompresses the refrigerant condensed by the condenser, and an evaporator that evaporates the refrigerant expanded by the expansion valve; a steam generator that generates steam by heat exchange between an intermediate fluid and water; and an intermediate fluid circulation flow path through which the intermediate fluid circulates between the condenser and the steam generator, wherein the intermediate fluid has a higher pressure than the steam generated by the steam generator.

[0064] 1A, 1B Steam generation system 3 Heat pump 5, 5' Intermediate fluid circulation passage 7 Steam generator 11 Refrigerant circulation passage 12 Compressor 13 Condenser 14 Expansion valve 15 Evaporator 17 Water pump 18 Heat medium pump 20 Pressure adjusting device 22 Compression pump 30 Water supply passage 32 Pressure reducing valve 34 Steam supply passage 35 Steam compressor 36 Supply amount adjusting section 37 Water injection pipe

Claims

1. A steam generation system comprising: a heat pump having a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that decompresses the refrigerant condensed by the condenser, and an evaporator that evaporates the refrigerant expanded by the expansion valve; a steam generator that generates steam from water by heat exchange between an intermediate fluid and the water; and an intermediate fluid circulation flow path through which the intermediate fluid circulates between the condenser and the steam generator, wherein the intermediate fluid has a higher pressure than the steam generated by the steam generator.

2. The steam generating system according to claim 1, further comprising a pressure reducing valve for reducing the pressure of the water supplied to the steam generator to below atmospheric pressure.

3. The steam generating system according to claim 1 or 2, wherein the intermediate fluid is at atmospheric pressure or higher.

4. The steam generating system according to claim 3, wherein the intermediate fluid is water or brine circulating in a liquid phase through the intermediate fluid circulation passage.

5. The steam generating system according to claim 4, further comprising a pressurizing means for pressurizing the intermediate fluid circulating through the intermediate fluid circulation passage to a pressure equal to or higher than atmospheric pressure.

6. The steam generating system according to claim 3, wherein the intermediate fluid is a fluid that evaporates in the condenser and condenses in the steam generator.

7. The steam generating system according to claim 6, wherein the steam generator is provided at a higher position than the condenser.

8. The steam generating system according to claim 6, further comprising a control means for controlling the liquid level of the intermediate fluid in the steam generator to be higher than the liquid level of the intermediate fluid in the condenser.

9. A method of generating steam using a steam generation system including: a heat pump having a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed by the compressor, an expansion valve that decompresses the refrigerant condensed by the condenser, and an evaporator that evaporates the refrigerant expanded by the expansion valve; a steam generator that generates steam by heat exchange between an intermediate fluid and water; and an intermediate fluid circulation flow path through which the intermediate fluid circulates between the condenser and the steam generator, wherein the intermediate fluid has a higher pressure than the steam generated by the steam generator.

Images