Cold heat recovery system and cold heat recovery system starting method

Abstract

A cold heat recovery system includes a first heat exchanger that transfers cold energy from liquefied gas to a cold heat medium, a cold heat recovery cycle that includes a cold heat pump provided on a downstream side of the first heat exchanger, a second heat exchanger that transfers heat energy from a heat carrier to the cold heat medium flowing between the cold heat pump and the first heat exchanger, a gas-liquid separator that is provided between the first heat exchanger and the cold heat pump and separates the cold heat medium into a gas phase and a liquid phase, a liquid return line for returning the liquid phase cold heat medium from between the cold heat pump and the second heat exchanger to the gas-liquid separator, and a third heat exchanger that transfers cold energy of the liquefied gas to the liquid phase cold heat medium returned to the gas-liquid separator via the liquid return line or the cold heat medium present inside the gas-liquid separator.

Description

Technical Field

[0001] This invention relates to a cold and heat recovery system for recovering cold energy from liquefied petroleum gas and a method for starting up the cold and heat recovery system.

[0002] This application claims priority based on Japanese Patent Application No. 2021-125923, filed with the Japan Patent Office on July 30, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] Liquefied gas (e.g., liquefied natural gas) is liquefied for the purpose of transportation and storage. When supplied to destinations such as city gas and thermal power plants, it is heated and vaporized by a heat medium such as seawater. In the process of vaporizing liquefied gas, sometimes the cold energy of the liquefied gas is not thrown into the seawater but is recovered (e.g., Patent Document 1).

[0004] Patent Document 1 discloses a thermal power generation cycle that recovers the cold energy of liquefied natural gas as electricity. As such a thermal power generation cycle, the secondary medium Rankine cycle and the like are known (see Patent Document 1). The secondary medium Rankine cycle involves heating and evaporating the secondary medium circulating in a closed loop in an evaporator using seawater as a heat source. This steam is then introduced into a turbine for thermal power generation to obtain power, and subsequently cooled and condensed using liquefied natural gas.

[0005] Because securing land and other resources requires significant investment, establishing onshore LNG bases corresponding to different LNG supply destinations is challenging. Therefore, sometimes ships equipped with LNG storage facilities and LNG regasification equipment are anchored at sea, and the LNG regasified on these ships is transported via pipelines to onshore supply destinations and offshore power plants (floating power plants).

[0006] Shipboard equipment lacks the scalability of land-based equipment, therefore miniaturization of thermal power generation systems, especially heat exchangers, is crucial for accommodating thermal power generation equipment. Examples of miniaturized heat exchangers include printed circuit heat exchangers (PCHEs) and plate heat exchangers.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Utility Model Application Publication No. 61-59803 Summary of the Invention

[0010] The technical problem to be solved by the invention

[0011] If the freezing point of one heat exchanger is lower than that of the other, one heat exchanger may solidify during heat exchange in the heat exchanger, and the solidified heat exchanger may adhere to the surface of the heat exchanger, causing blockage. Small heat exchangers have a higher risk of blockage than large heat exchangers (e.g., shell-and-tube heat exchangers), thus posing a reliability challenge.

[0012] In a cooling-heating power generation cycle, the heat exchanger may freeze when liquefied natural gas (LNG) is used to cool the secondary medium circulating in the cycle. This is especially true when starting a cooling-heating power generation cycle with a small flow rate of the secondary medium; the temperature of the secondary medium drops compared to stable operation, thus increasing the likelihood of heat exchanger freezing. To prevent heat exchanger freezing, preheating lines for the LNG supplied to the heat exchanger could be considered, but such heating lines would lead to larger or more expensive systems with cooling-heating power generation cycles, and are therefore not preferred.

[0013] Furthermore, to prevent the heat exchanger from freezing, it is advisable to increase the flow rate of the secondary medium circulating in the cooling and heating power generation cycle when starting it up. However, when the cooling and heating power generation cycle stops, the secondary medium in the cycle may sometimes vaporize due to heat input from the surrounding air. Therefore, when starting up the cooling and heating power generation cycle, the proportion of gaseous secondary medium in the circulation pump used to circulate the secondary medium is larger compared to when the cycle is running stably. Increasing the circulation rate of the circulation pump used to circulate the secondary medium increases the possibility of poor start-up due to cavitation of the circulation pump when starting up the cooling and heating power generation cycle.

[0014] In view of the above, the object of at least one embodiment of the present invention is to provide a heat recovery system capable of suppressing blockage of the heat exchanger when starting the heat recovery system and a method for starting the heat recovery system.

[0015] Technical means for solving the problem

[0016] One embodiment of the present invention relates to a heat recovery system installed on a ship or buoy having a liquefied gas storage device configured to store liquefied gas, comprising:

[0017] The first heat exchanger is configured to transfer cold energy from the liquefied gas extracted from the liquefied gas storage device to a heat medium for heating and cooling.

[0018] The heat recovery cycle is configured to circulate the heat medium and includes at least a heat pump for conveying the heat medium, located downstream of the first heat exchanger.

[0019] The second heat exchanger is configured to transfer heat energy from a heat carrier to the heat medium flowing downstream of the heat pump in the heat recovery cycle and upstream of the first heat exchanger.

[0020] A gas-liquid separator is disposed between the first heat exchanger and the cold and heat pump in the cold and heat recovery cycle, and is configured to separate the cold and heat heat medium into a gas phase cold and heat heat medium and a liquid phase cold and heat heat medium.

[0021] A liquid return line is provided for returning the liquid-phase heating medium from the downstream side of the heating pump in the heating and cooling recovery cycle and the upstream side of the second heat exchanger to the gas-liquid separator; and

[0022] The third heat exchanger is configured to transfer the cold energy of the liquefied gas extracted from the liquefied gas storage device to either the liquid phase heating medium that returns to the gas-liquid separator via the liquid return line, or the heating medium that exists inside the gas-liquid separator.

[0023] One embodiment of the present invention relates to a method for starting up a heat recovery system, specifically a method for starting up a heat recovery system installed on a ship or buoy having a liquefied gas storage device configured to store liquefied gas.

[0024] The heat recovery system includes:

[0025] The first heat exchanger is configured to transfer cold energy from the liquefied gas extracted from the liquefied gas storage device to a heat medium for heating and cooling.

[0026] A heat recovery cycle is configured to circulate the heat transfer medium, and includes at least a heat pump for conveying the heat transfer medium located downstream of the first heat exchanger; and

[0027] The second heat exchanger is configured to transfer heat energy from a heat carrier to the heating medium flowing downstream of the heating pump in the heat recovery cycle and upstream of the first heat exchanger.

[0028] The startup method of the heat recovery system includes the following steps:

[0029] In the gas-liquid separation step, a gas-liquid separator located between the first heat exchanger and the cold and heat pump in the cold and heat recovery cycle separates the cold and heat heat medium into a gas phase cold and heat heat medium and a liquid phase cold and heat heat medium.

[0030] In the circulation step, the heating and cooling pump is driven to return the liquid-phase heating and cooling medium separated in the gas-liquid separation step to the gas-liquid separator via a liquid return pipeline. The liquid return pipeline is connected downstream of the heating and cooling pump in the heating and cooling recovery cycle and upstream of the second heat exchanger to the gas-liquid separator.

[0031] The cooling step involves transferring and cooling either the liquid-phase heating medium that returns to the gas-liquid separator via the liquid return line during the circulation step, or the heating medium that exists inside the gas-liquid separator, to either the liquefied gas extracted from the gas storage device.

[0032] Invention Effects

[0033] According to at least one embodiment of the present invention, a heat recovery system capable of suppressing blockage of the heat exchanger when starting the heat recovery system and a method for starting the heat recovery system can be provided. Attached Figure Description

[0034] Figure 1 This is a schematic structural diagram illustrating the structure of a ship or buoy equipped with a heat recovery system according to an embodiment of the present invention.

[0035] Figure 2 This is a flowchart of a startup method for a heat recovery system according to one embodiment of the present invention.

[0036] Figure 3 This is an explanatory diagram illustrating an example of control in a heat recovery system according to one embodiment of the present invention.

[0037] Figure 4 This is a schematic structural diagram illustrating the structure of a ship or buoy equipped with a heat recovery system according to an embodiment of the present invention.

[0038] Figure 5 This is a schematic structural diagram illustrating the structure of a ship or buoy equipped with a heat recovery system according to an embodiment of the present invention.

[0039] Figure 6 This is a schematic structural diagram illustrating the structure of a ship or buoy equipped with a heat recovery system according to an embodiment of the present invention.

[0040] Figure 7 This is a schematic structural diagram illustrating the structure of a ship or buoy equipped with a heat recovery system according to an embodiment of the present invention.

[0041] Figure 8This is a schematic structural diagram illustrating the structure of a ship or buoy equipped with a heat recovery system according to an embodiment of the present invention.

[0042] Figure 9 This is an explanatory diagram illustrating the control device of a heat recovery system according to one embodiment of the present invention. Detailed Implementation

[0043] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of the constituent components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention thereto.

[0044] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" that indicate relative or absolute configurations not only strictly indicate such configurations, but also indicate the state of relative displacement by angle or distance with tolerance or the degree to which the same function can be obtained.

[0045] For example, expressions such as "same," "equal," and "homogeneous" that indicate the state of equality of things not only strictly indicate the state of equality, but also indicate the state of difference in the degree to which there is tolerance or the ability to obtain the same function.

[0046] For example, the expressions representing shapes such as quadrilaterals and cylindrical shapes not only represent shapes such as quadrilaterals and cylindrical shapes in a strict geometric sense, but also, within the range where the same effect can be achieved, shapes including concave and convex parts and chamfered parts.

[0047] On the other hand, expressions that "possess," "include," or "have" a constituent element are not exclusive expressions that exclude the existence of other constituent elements.

[0048] In addition, sometimes the same symbols are used to mark the same structures, and the explanation is omitted.

[0049] (ships, floating bodies)

[0050] Figure 1 This is a schematic structural diagram illustrating the structure of a ship 2A or a float 2B equipped with the heat recovery system 1 according to one embodiment of the present invention. Figure 1As shown, the heat recovery system 1 involved in several embodiments is installed on a ship 2A or a floating body 2B. The ship 2A or floating body 2B is a structure capable of floating on water. The ship 2A or floating body 2B has a liquefied gas storage device (e.g., a liquefied gas tank) 21 configured to store liquefied gas and the heat recovery system 1. In the illustrated embodiment, the ship 2A or floating body 2B has a propeller (not shown) and a propulsion device (not shown) configured to drive the propeller, and is a structure configured to be self-propelled by driving the propulsion device. Furthermore, the present invention can also be applied to cases where the ship 2A or floating body 2B is a non-self-propelled structure without a propulsion device for self-propelled movement.

[0051] (Heat and cold recovery system)

[0052] like Figure 1 As shown, the heat recovery system 1 includes: a first heat exchanger 11; a liquefied gas supply line 12 for supplying liquefied gas from the liquefied gas storage device 21 to the first heat exchanger 11; a vaporized gas supply line 13 for supplying vaporized gas generated by vaporizing liquefied gas in the first heat exchanger 11; a heat recovery cycle 3 configured to circulate a heat exchange medium for exchanging heat with liquefied gas in the first heat exchanger 11; a second heat exchanger 14; and a gas-liquid separator 5.

[0053] (Heat and cold recovery cycle)

[0054] The heat recovery cycle 3 is configured to circulate the heat transfer medium in an organic Rankine cycle. In the following description, the upstream side of the circulation direction of the heat transfer medium in the heat recovery cycle 3 is sometimes simply referred to as the upstream side, and the downstream side of the aforementioned circulation direction is sometimes simply referred to as the downstream side. The heat recovery cycle 3 includes a heat transfer pump 31 for conveying the heat transfer medium and a heat transfer turbine 32 configured to be driven by the heat transfer medium. In the heat recovery cycle 3, the heat transfer pump 31 is located downstream of the first heat exchanger 11 and upstream of the second heat exchanger 14. In the heat recovery cycle 3, the heat transfer turbine 32 is located upstream of the first heat exchanger 11 and downstream of the second heat exchanger 14.

[0055] The following description uses liquefied natural gas (LNG) as a specific example of LNG supplied from the LNG storage unit 21, which serves as the LNG supply source, and propane as a specific example of the heating medium circulating in the heat recovery cycle 3. However, the present invention can also be applied to cases where other liquefied gases (such as liquefied petroleum gas, liquid hydrogen, etc.) are supplied from the LNG storage unit 21. Furthermore, the present invention can also be applied to cases where other heating media (such as organic media) are used as the heating medium flowing in the heat recovery cycle 3. Additionally, the boiling point and freezing point of the heating medium are lower than those of water.

[0056] (Heat Exchanger 1)

[0057] The first heat exchanger (liquefied gas vaporizer, hot and cold side condenser) 11 is configured to exchange heat between liquefied gas supplied from the liquefied gas supply line 12 and a hot and cold medium flowing downstream of the hot and cold turbine 32 and upstream of the hot and cold pump 31 in the hot and cold recovery cycle 3. In the illustrated embodiment, the first heat exchanger 11 includes a first liquefied gas side flow path 111 for the liquefied gas supplied from the liquefied gas supply line 12 and a first hot and cold side flow path 112 for the hot and cold medium circulating in the hot and cold recovery cycle 3. The temperature of the liquefied gas flowing in the first liquefied gas side flow path 111 is lower than the temperature of the hot and cold medium flowing in the first hot and cold side flow path 112.

[0058] In the first heat exchanger 11, liquefied gas flowing in the first liquefied gas side flow path 111 exchanges heat with a hot / cold heat transfer medium flowing in the first hot / cold side flow path 112. The cold energy of the liquefied gas flowing in the first liquefied gas side flow path 111 is transferred to the hot / cold heat transfer medium flowing in the first hot / cold side flow path 112. As a result, the liquefied gas flowing in the first liquefied gas side flow path 111 is heated and vaporized, while the hot / cold heat transfer medium flowing in the first hot / cold side flow path 112 is cooled and condensed.

[0059] (Second heat exchanger)

[0060] The second heat exchanger (hot and cold side evaporator) 14 is configured to exchange heat between external water (heat carrier) introduced from outside the heat recovery system 1 and a hot and cold medium flowing downstream of the heat recovery pump 31 and upstream of the heat recovery turbine 32 in the heat recovery cycle 3. In the illustrated embodiment, the second heat exchanger 14 includes a second hot and cold side flow path 141 for the hot and cold medium and a heat carrier side flow path 142 for the external water. In the heat recovery cycle 3, the second hot and cold side flow path 141 (second heat exchanger 14) is located downstream of the heat recovery pump 31 and upstream of the heat recovery turbine 32. The temperature of the external water flowing in the heat carrier side flow path 142 is higher than the temperature of the hot and cold medium flowing in the second hot and cold side flow path 141.

[0061] In the second heat exchanger 14, heat exchange occurs between the heating medium flowing in the second hot / cold side flow path 141 and the external water flowing in the heat carrier side flow path 142. The thermal energy of the external water flowing in the heat carrier side flow path 142 is transferred to the heating medium flowing in the second hot / cold side flow path 141. As a result, the heating medium flowing in the second hot / cold side flow path 141 is heated and vaporized.

[0062] (Liquefied petroleum gas supply system)

[0063] One side (upstream end) of the liquefied gas supply pipeline 12 is connected to the liquefied gas storage device 21, and the other side (downstream end) of the liquefied gas supply pipeline 12 is connected to the upstream end (gas inlet of the first heat exchanger 11) of the first liquefied gas side flow path 111. One side (upstream end) of the vaporized gas supply pipeline 13 is connected to the downstream end (gas outlet of the first heat exchanger 11) of the first liquefied gas side flow path 111, and the other side (downstream end) of the vaporized gas supply pipeline 13 is connected to the vaporized gas supply destination 22. Furthermore, the vaporized gas supply destination 22 can be equipment located outside the ship 2A or the floating body 2B (e.g., onshore power generation equipment or gas storage equipment), or it can be equipment mounted on the ship 2A or the floating body 2B.

[0064] The heat recovery system 1 also includes a liquefied gas pump 15 installed in the liquefied gas supply line 12. The liquefied gas pump 15 has rotating blades (not shown) installed in the liquefied gas supply line 12, and is configured to rotate these blades using electricity or the like supplied to the liquefied gas pump 15, thereby supplying liquefied gas to the downstream side of the liquefied gas supply line 12 (the side where the first heat exchanger 11 is located). By driving the liquefied gas pump 15, liquefied gas stored in the liquefied gas storage device 21 is drawn out to the liquefied gas supply line 12 and transported through the liquefied gas supply line 12 to the first liquefied gas side flow path 111 of the first heat exchanger 11. The vaporized gas generated by the vaporization of liquefied gas in the first liquefied gas side flow path 111 of the first heat exchanger 11 is transported by the liquefied gas pump 15 through the vaporized gas supply line 13 to the gas supply destination 22.

[0065] (External water supply system)

[0066] The heat recovery system 1 also includes: an external water supply line 42 for supplying external water from an external water supply source 41 to a heat exchanger (second heat exchanger 14) that uses external water as a heat carrier; an external water discharge line 44 for discharging external water discharged from the aforementioned heat exchanger that uses external water as a heat carrier to an external water discharge destination 43; and an external water pump 45 installed in the external water supply line 42.

[0067] One side (upstream end) of the external water supply pipe 42 is connected to the external water supply source 41, and the other side (downstream end) of the external water supply pipe 42 is connected to the upstream end (heat carrier inlet of the second heat exchanger 14) of the heat carrier side flow path 142. One side (upstream end) of the external water discharge pipe 44 is connected to the downstream end (heat carrier outlet of the second heat exchanger 14) of the heat carrier side flow path 142, and the other side (downstream end) of the external water discharge pipe 44 is connected to the external water discharge destination 43. The external water can be any water that can be used as a heat carrier to heat the heat exchange object in the heat exchanger (water at a higher temperature than the heat exchange object), or it can be water at room temperature. The external water is preferably water that is readily available in the ship 2A or the buoy 2B (e.g., seawater or other external water, or engine cooling water for cooling the engine of the ship 2A).

[0068] The external water supply source 41 can be a water intake on the vessel 2A or the float 2B for taking in external water (e.g., seawater) from the outside of the vessel 2A or the float 2B, or it can be a device (e.g., a water storage tank) installed inside the vessel 2A or the float 2B. Similarly, the external water discharge destination 43 can be a drain outlet on the vessel 2A or the float 2B for discharging external water to the outside of the vessel 2A or the float 2B, or it can be a device (e.g., a drainage trough) installed inside the vessel 2A or the float 2B.

[0069] The external water pump 45 has rotating blades (not shown) installed in the external water supply line 42, and is configured to rotate the blades using electricity or the like supplied to the external water pump 45, thereby supplying external water to the downstream side of the external water supply line 42 (the side where the second heat exchanger 14 is located). By driving the external water pump 45, external water is drawn from the external water supply source 41 to the external water supply line 42, and then transported through the external water supply line 42 to the heat exchanger (second heat exchanger 14) that uses the external water as a heat carrier.

[0070] (Heat medium circulation system for both heating and cooling)

[0071] like Figure 1 As shown, the heat recovery cycle 3 also includes a first connecting pipe 33 and a second connecting pipe 34. The first connecting pipe 33 connects the downstream end of the first heat-side flow path 112 (the outlet of the heat medium for heat exchanger 11) to the upstream end of the second heat-side flow path 141 (the inlet of the heat medium for heat exchanger 14). The aforementioned heat pump 31 is installed in the first connecting pipe 33. The second connecting pipe 34 connects the downstream end of the second heat-side flow path 141 (the outlet of the heat medium for heat exchanger 14) to the upstream end of the first heat-side flow path 112 (the inlet of the heat medium for heat exchanger 11). The aforementioned heat turbine 32 is installed in the second connecting pipe 34.

[0072] (Gas-liquid separator)

[0073] The gas-liquid separator 5 is configured to separate the heating medium for heating and cooling into a gas phase and a liquid phase. In the heating and cooling recovery cycle 3, the gas-liquid separator 5 is located downstream of the first heating and cooling side flow path 112 (first heat exchanger 11) and upstream of the heating and cooling pump 31. Specifically, the gas-liquid separator 5 is located upstream of the heating and cooling pump 31 in the first connecting pipe 33.

[0074] The gas-liquid separator 5 includes: a main body 52 configured to define an internal space 51 in which a hot or cold medium is introduced from the first hot or cold side flow path 112 (first heat exchanger 11) via a first connecting pipe 33; an inlet 53 for introducing the hot or cold medium into the internal space 51; and a liquid phase outlet 54 for discharging the liquid phase hot or cold medium from the internal space 51 to the outside of the gas-liquid separator 5.

[0075] The internal space 51 includes: a lower storage space 51B for storing a liquid-phase heating medium; and an upper storage space 51A above the lower storage space 51B for storing a gaseous heating medium that is connected to the lower storage space 51B. A liquid discharge port 54 is connected to the lower storage space 51B.

[0076] The first connecting pipe 33 mentioned above includes: a first upper connecting pipe 33A, which connects the downstream end of the first hot and cold side flow path 112 to the inlet 53; a first middle connecting pipe 33B, which connects the liquid phase outlet 54 to the pump inlet 311 of the hot and cold pump 31; and a first lower connecting pipe 33C, which connects the pump outlet 312 of the hot and cold pump 31 to the upstream end of the second hot and cold side flow path 141.

[0077] The hot and cold medium cooled in the first heat exchanger 11 is guided to the gas-liquid separator 5 through the first upper connecting pipe 33A. The hot and cold medium flowing into the internal space 51 from the inlet 53 is separated into liquid and gas phases in the internal space 51.

[0078] (Pump for both heating and cooling)

[0079] The heating / cooling pump 31 is configured to deliver a heating / cooling medium to the downstream side of the heating / cooling recovery cycle 3 (the side where the second heat exchanger 14 is located). The heating / cooling pump 31 has a rotating blade (not shown) installed in the first connecting pipe 33, and is configured to rotate the rotating blade using electricity or the like supplied to the heating / cooling pump 31, thereby delivering a liquid-phase heating / cooling medium to the downstream side of the first connecting pipe 33.

[0080] By driving the heating and cooling pump 31, the liquid-phase heating and cooling medium stored in the lower storage space 51B is guided to the heating and cooling pump 31 through the liquid discharge port 54 and the first intermediate connecting pipe 33B, and is pressurized by the heating and cooling pump 31. The liquid-phase heating and cooling medium pressurized by the heating and cooling pump 31 is then transported by the heating and cooling pump 31 through the first lower connecting pipe 33C to the second heating and cooling side flow path 141 (the second heat exchanger 14).

[0081] (Equipment related to heating and cooling pumps)

[0082] like Figure 1 As shown, the heat recovery system 1 further includes: a liquid return line 6 for returning the liquid-phase heat transfer medium from the downstream side of the heat pump 31 in the heat recovery cycle 3 and the upstream side of the second heat exchanger 14 to the gas-liquid separator 5; and a first flow regulating valve 35, disposed between the connection P1 at the upstream end of the liquid return line 6 in the heat recovery cycle 3 and the second heat exchanger 14. The first flow regulating valve 35 is configured to adjust the flow rate of the liquid-phase heat transfer medium guided to the second heat exchanger 14.

[0083] In the illustrated embodiment, the gas-liquid separator 5 further includes a liquid return port 55 for introducing liquid-phase heating / cooling medium from the liquid return line 6 into the internal space 51. The liquid return port 55 communicates with the internal space 51. One side (upstream end) of the liquid return line 6 is connected to the connection portion P1 of the first lower section connecting line 33C, and the other side (downstream end) of the liquid return line 6 is connected to the liquid return port 55. A first flow regulating valve 35 is provided downstream of the connection portion P1 of the first lower section connecting line 33C. The first flow regulating valve 35 can adjust the flow rate of the heating / cooling medium supplied to the downstream side (second heat exchanger 14 side) of the valve body by moving a valve body (not shown) that opens and closes the flow path of the heating / cooling medium. In addition, the first flow regulating valve 35 can be an on / off valve whose opening degree can be adjusted to be completely closed and completely open, or an opening regulating valve whose opening degree can be adjusted to be completely closed, completely open, and at least one intermediate opening degree in between.

[0084] (Turbine for heating and cooling)

[0085] A heating / cooling medium, pressurized by a heating / cooling pump 31 and heated in a second heat exchanger 14, is introduced as the working fluid into a heating / cooling turbine 32. The heating / cooling turbine 32 includes a rotating shaft 321, turbine blades 322 mounted on the rotating shaft 321, and a housing 323 rotatably housing the turbine blades 322. An inlet 324 for introducing the heating / cooling medium into the housing 323 and an outlet 325 for discharging the heating / cooling medium that has passed through the turbine blades 322 to the outside of the housing 323 are formed on the housing 323. The heating / cooling turbine 32 is configured to rotate the turbine blades 322 using the energy of the heating / cooling medium introduced into the housing 323 through the inlet 324. The heating / cooling medium that has passed through the turbine blades 322 is discharged to the outside of the housing 323 through the outlet 325.

[0086] The heat recovery cycle 3 is configured to recover the rotational force generated by the turbine blades 322 as power. In the illustrated embodiment, the heat recovery cycle 3 also includes a heat recovery generator 326, which is configured to generate electricity by driving the heat recovery turbine 32. The heat recovery generator 326 is mechanically connected to the rotating shaft 321 and is configured to convert the rotational force of the turbine blades 322 into electricity. Alternatively, in several other embodiments, the heat recovery cycle 3 may not convert the rotational force generated by the turbine blades 322 into electricity, but instead recover power directly through a power transmission device (e.g., coupling, belt, pulley, etc.).

[0087] The second connecting pipe 34 mentioned above includes: a second upper connecting pipe 34A, which connects the downstream end of the second hot and cold side flow path 141 to the inlet 324 of the hot and cold turbine 32; and a second lower connecting pipe 34B, which connects the outlet 325 of the hot and cold turbine 32 to the upstream end of the first hot and cold side flow path 112.

[0088] (Turbine-related equipment for heating and cooling)

[0089] like Figure 1 As shown, the heat recovery cycle 3 also includes: a turbine bypass pipe 36, which bypasses the heat recovery turbine 32 and connects the upstream and downstream sides of the heat recovery turbine 32 of the second connecting pipe 34; a turbine side flow regulating valve 37; and a turbine bypass side flow regulating valve 38.

[0090] One side (upstream end) of the turbine bypass pipe 36 is connected to a branch P2 of the second upper connecting pipe 34A, and the other side (downstream end) of the turbine bypass pipe 36 is connected to a confluence P3 of the second lower connecting pipe 34B. A turbine-side flow regulating valve 37 is located downstream of the branch P2 of the second upper connecting pipe 34A (on the side of the heating / cooling turbine 32). A turbine bypass-side flow regulating valve 38 is located in the turbine bypass pipe 36. Both the turbine-side flow regulating valve 37 and the turbine bypass-side flow regulating valve 38 can adjust the flow rate of the heating / cooling medium supplied downstream of the valve body by moving a valve body (not shown) that opens and closes the flow path of the heating / cooling medium. Furthermore, the turbine-side flow regulating valve 37 and the turbine bypass-side flow regulating valve 38 can be either fully closed or fully open valves, or opening regulating valves that can be adjusted to fully closed, fully open, or at least one intermediate opening.

[0091] By opening the turbine-side flow regulating valve 37 (fully open or partially open) and setting the turbine bypass-side flow regulating valve 38 to fully close, a cooling or heating medium can be supplied to the first heat exchanger 11 via the cooling or heating turbine 32. Furthermore, by setting the turbine-side flow regulating valve 37 to fully close and opening the turbine bypass-side flow regulating valve 38 (fully open or partially open), a cooling or heating medium can be supplied to the first heat exchanger 11 via the turbine bypass line 36.

[0092] (Third heat exchanger)

[0093] like Figure 1 As shown, the heat recovery system 1 according to several embodiments also includes a third heat exchanger 7, which is configured to transfer the cold energy of the liquefied gas extracted from the liquefied gas storage device 21 to either the liquid phase heat medium that returns to the gas-liquid separator 5 via the liquid return line 6, or the heat medium that exists inside the gas-liquid separator 5.

[0094] The third heat exchanger (precooler) 7 is configured to exchange heat between liquefied gas extracted from the liquefied gas storage unit 21 and a hot or cold medium circulating via the gas-liquid separator 5 or the liquid return line 6. Figure 1 In the illustrated embodiment, the third heat exchanger 7 (7A) includes a third hot / cold side flow path 71 for the flow of a hot / cold medium disposed in the liquid return line 6 and a second liquefied gas side flow path 72 for the flow of liquefied gas. The temperature of the hot / cold medium flowing in the third hot / cold side flow path 71 is higher than the temperature of the liquefied gas flowing in the second liquefied gas side flow path 72.

[0095] In the third heat exchanger 7 (7A), heat exchange occurs between the hot / cold medium flowing in the third hot / cold side flow path 71 and the liquefied gas flowing in the second liquefied gas side flow path 72. The cold energy of the liquefied gas flowing in the second liquefied gas side flow path 72 is transferred to the hot / cold medium flowing in the third hot / cold side flow path 71. As a result, the hot / cold medium flowing in the third hot / cold side flow path 71 is cooled.

[0096] (Liquefied gas introduction system for precooler)

[0097] like Figure 1 As shown, the heat recovery system 1 also includes: a liquefied gas inlet pipe 81 for guiding liquefied gas from the liquefied gas storage device 21 to the third heat exchanger 7; and a gas outlet pipe 82 for guiding vaporized gas formed by the vaporization of liquefied gas from the third heat exchanger 7.

[0098] exist Figure 1 In the illustrated embodiment, one side (upstream end) of the liquefied gas inlet pipe 81 is connected to the downstream connection point P4 of the liquefied gas pump 15 of the liquefied gas supply pipe 12. The other side (downstream end) of the liquefied gas inlet pipe 81 is connected to the upstream end (gas inlet of the third heat exchanger 7) of the second liquefied gas side flow path 72. One side (upstream end) of the gas outlet pipe 82 (82A) is connected to the downstream end (gas outlet of the third heat exchanger 7) of the second liquefied gas side flow path 72. The other side (downstream end) of the gas outlet pipe 82 (82A) is connected to the connection point P5 of the vaporized gas supply pipe 13.

[0099] By driving the liquefied gas pump 15, the liquefied gas stored in the liquefied gas storage device 21 is drawn out to the liquefied gas supply line 12, and is transported to the second liquefied gas side flow path 72 of the third heat exchanger 7 through the upstream part of the connection position P4 of the liquefied gas supply line 12 and the liquefied gas inlet line 81.

[0100] The vaporized gas generated by the vaporization of liquefied gas in the second liquefied gas side flow path 72 of the third heat exchanger 7 is transported to the gas supply destination 22 by the liquefied gas pump 15 through the downstream part of the connection position P5 of the gas discharge line 82 (82A) and the vaporized gas supply line 13.

[0101] exist Figure 1In the illustrated embodiment, the heat recovery system 1 further includes a second flow regulating valve 83, a third flow regulating valve 84, a fourth flow regulating valve 85, and a fifth flow regulating valve 86. Furthermore, the second flow regulating valve 83 is an opening regulating valve capable of adjusting its opening to fully closed, fully open, and at least one intermediate opening in between. The flow regulating valves 84, 85, and 86 can be on / off valves capable of adjusting their opening to fully closed and fully open, or opening regulating valves capable of adjusting their opening to fully closed, fully open, and at least one intermediate opening in between.

[0102] The second flow regulating valve 83 is provided in the liquefied gas inlet pipe 81 and is configured to regulate the flow rate of liquefied gas guided to the third heat exchanger 7. The third flow regulating valve 84 is provided downstream of the connection point P4 of the liquefied gas supply pipe 12 and is configured to regulate the flow rate of liquefied gas guided to the first heat exchanger 11. By opening the second flow regulating valve 83 (fully open or partially open) and setting the third flow regulating valve 84 to be fully closed, liquefied gas can be supplied from the liquefied gas storage device 21 to the third heat exchanger 7 using the liquefied gas pump 15. Furthermore, by setting the second flow regulating valve 83 to be fully closed and opening the third flow regulating valve 84 (fully open or partially open), liquefied gas can be supplied from the liquefied gas storage device 21 to the first heat exchanger 11 using the liquefied gas pump 15.

[0103] The fourth flow regulating valve 85 is located upstream of the connection point P5 of the vaporized gas supply line 13 and is configured to regulate the flow rate of the vaporized gas guided to the gas supply destination 22. The fifth flow regulating valve 86 is located in the gas discharge line 82 and is configured to regulate the flow rate of the vaporized gas guided to the gas supply destination 22. By opening the fourth flow regulating valve 85 (fully open or partially open) and setting the fifth flow regulating valve 86 to be fully closed, the liquefied gas pump 15 can deliver a hot or cold heat medium from the first heat exchanger 11 to the gas supply destination 22. Furthermore, by setting the fourth flow regulating valve 85 to be fully closed and opening the fifth flow regulating valve 86 (fully open or partially open), the liquefied gas pump 15 can deliver a hot or cold heat medium from the third heat exchanger 7 to the gas supply destination 22.

[0104] (Start-up method for a heat recovery system)

[0105] Figure 2 This is a flowchart of a startup method for a heat recovery system according to one embodiment of the present invention. Figure 3 This is an explanatory diagram illustrating an example of control in a heat recovery system according to one embodiment of the present invention. Figure 2 , Figure 3As shown, the period from the start-up of the heat recovery system 1 to its stable operation is divided into three periods: the first period (pre-cooling period) T1, the second period (transition period) T2, and the third period (heat recovery period) T3. The second period T2 is the period after the first period T1 and the period before the third period T3.

[0106] During the first period T1, liquefied gas extracted from the liquefied gas storage unit 21 is transported to the third heat exchanger 7. During the third period T3, liquefied gas extracted from the liquefied gas storage unit 21 is transported to the first heat exchanger 11. During the second period T2, the destination of the liquefied gas extracted from the liquefied gas storage unit 21 is changed from the third heat exchanger 7 to the first heat exchanger 11.

[0107] like Figure 2 As shown, the start-up method 100 of the heat recovery system 1 according to several embodiments includes a gas-liquid separation step S101, a circulation step S102 and a cooling step S103.

[0108] In the gas-liquid separation step S101, the gas-liquid separator 5 separates the heating medium for heating and cooling into a gas phase and a liquid phase. The gas-liquid separation step S101 is performed continuously from the start-up of the heat recovery system 1 until stable operation and during stable operation.

[0109] When the heat recovery system 1 is shut down, the heating medium in the heat recovery cycle 3 may sometimes vaporize due to the heat input from the surrounding air to the heat recovery cycle 3 or the gas-liquid separator 5. Therefore, compared to when the heat recovery system 1 is running stably, the proportion of the gaseous heating medium downstream of the first heat exchanger 11 and in the second heat exchanger 14 of the heat recovery cycle 3, such as the gas-liquid separator 5 or the heating pump 31, increases during startup. If the proportion of the gaseous heating medium in the heating pump 31 is high, it may lead to a decrease in capacity caused by cavitation of the heating pump 31.

[0110] In the circulation step S102, the heating / cooling pump 31 is driven to return the liquid-phase heating / cooling medium separated in the gas-liquid separation step S101 to the gas-liquid separator 5 via the liquid return line 6. Thus, the liquid-phase heating / cooling medium circulates within the gas-liquid separator 5, the heating / cooling pump 31, and the liquid return line 6. The circulation step S102 begins in the first period T1 and continues until the second period T2.

[0111] Specifically, in cycle step S102, with the first flow regulating valve 35 fully closed, the cooling and heating pump 31 is driven to extract the liquid-phase cooling and heating medium from the gas-liquid separator 5 via the liquid phase discharge port 54. The liquid-phase cooling and heating medium extracted from the gas-liquid separator 5 is transported to the gas-liquid separator 5 after passing through the upstream side of the connection P1 between the cooling and heating pump 31, the first intermediate connecting pipe 33B, the cooling and heating pump 31, and the first lower connecting pipe 33C, and the liquid return pipe 6.

[0112] In the cooling step S103, the cold energy of the liquefied gas extracted from the liquefied gas storage device 21 is transferred to either the liquid phase heating medium that returns to the gas-liquid separator 5 via the liquid return pipe 6 in the circulation step S102, or the heating medium that exists inside the gas-liquid separator 5, and the liquefied gas is cooled.

[0113] In cooling step S103, liquefied gas is supplied from the liquefied gas storage device 21 to the third heat exchanger 7, where it is used to cool the heating medium. Thus, the liquid-phase heating medium circulating in the gas-liquid separator 5, the heating pump 31, and the liquid return line 6 is cooled. In the illustrated embodiment, cooling step S103 begins after circulation step S102 in the first period T1. Figure 3 As shown, the liquefied gas pump 15 is driven after the cooling and heating pump 31 is driven.

[0114] Specifically, in the cooling step S103, the liquefied gas pump 15 is driven with the second flow regulating valve 83 or the fifth flow regulating valve 86 open (fully open or partially open) and the third flow regulating valve 84 or the fourth flow regulating valve 85 fully closed. This allows liquefied gas to be supplied from the liquefied gas storage device 21 to the third heat exchanger 7, and vaporized gas to be supplied from the third heat exchanger 7 to the gas supply destination 22.

[0115] In cooling step S103, the liquid-phase heating medium circulating in the gas-liquid separator 5, the heating / cooling pump 31, and the liquid return line 6 is cooled, thereby reducing the internal temperature of the gas-liquid separator 5 and causing the gas-phase heating / cooling medium present inside the gas-liquid separator 5 to condense. This allows for an earlier increase in the proportion of the liquid-phase heating / cooling medium in the downstream side of the first heat exchanger 11 and the upstream side of the second heat exchanger 14 in the heat recovery cycle 3, including the gas-liquid separator 5 and the heating / cooling pump 31. By increasing the proportion of the liquid-phase heating / cooling medium in the heating / cooling pump 31, the capacity reduction caused by cavitation of the heating / cooling pump 31 can be suppressed, thus enabling the heating / cooling pump 31 to operate at its full capacity from an earlier stage.

[0116] like Figure 2As shown, in the illustrated embodiment, the start-up method 100 of the heat recovery system 1 further includes: a valve opening step S104, which opens the first flow regulating valve 35 (changing from completely closed to fully open or intermediate opening) after the start of the cooling step S103, and the heat pump 31 delivers the heat medium to the first heat exchanger 11; a change step S105, which changes the destination of the liquefied gas extracted from the liquefied gas storage device 21 from the third heat exchanger 7 to the first heat exchanger 11 after the valve opening step S104; a heat turbine driving step S106, which guides the heat medium to the heat turbine 32 after the change step S105 and drives the heat turbine 32; and an external water pump driving step S107, which drives the external water pump 45 before the valve opening step S104.

[0117] The valve opening step S104 is performed, for example, when the internal temperature of the gas-liquid separator 5 is below a predetermined temperature (the condensation temperature of the heating medium for heating or cooling). After the internal temperature of the gas-liquid separator 5 is below the predetermined temperature, the internal temperature of the gas-liquid separator 5 is maintained within a predetermined range with the predetermined temperature as the upper limit by adjusting the second flow regulating valve 83. The liquid phase heating medium for heating or cooling, after passing through the first flow regulating valve 35, is heated and vaporized in the second heat exchanger 14 and then transported to the first heat exchanger 11.

[0118] Specifically, the liquid-phase heating and cooling medium that has passed through the first flow regulating valve 35 is transported to the first heating and cooling side flow path 112 (first heat exchanger 11) after passing downstream of the first flow regulating valve 35 in the first lower connecting pipe 33C, the second heating and cooling side flow path 141 (second heat exchanger 14), the upstream side of the branch P2 of the second upper connecting pipe 34A, the downstream side of the confluence P3 of the turbine bypass pipe 36 and the second lower connecting pipe 34B. Figure 3 As shown, during the first period T1 and the second period T2, by setting the turbine-side flow regulating valve 37 to be completely closed and opening the turbine bypass-side flow regulating valve 38 (fully open or at an intermediate opening), the heat medium for heating or cooling can be supplied to the first heat exchanger 11 via the turbine bypass line 36.

[0119] Before the valve opening step S104, the external water pump 45 is driven (S107) to supply external water to the heat carrier side flow path 142 of the second heat exchanger 14. The liquid-phase heating medium that has passed through the first flow regulating valve 35 is heated and vaporized by the external water (heat carrier) in the second heat exchanger 14. Before performing the change step S105, no heat exchange occurs between the liquefied gas and the heating medium in the first heat exchanger 11. The gaseous heating medium that has passed through the first heat exchanger 11 is condensed in the gas-liquid separator 5, which is internally cooled by the third heat exchanger 7.

[0120] In addition, in the valve opening step S104, by adjusting the opening degree of the first flow regulating valve 35, the amount of liquid phase heating medium inside the gas-liquid separator 5 can be stabilized.

[0121] By performing the change step S105 during the second period T2, the destination of the liquefied gas extracted from the liquefied gas storage device 21 is changed from the third heat exchanger 7 to the first heat exchanger 11. The cooling and heating turbine drive step S106 is performed during the third period T3. That is, the cooling and heating turbine drive step S106 is performed after the change step S105.

[0122] The modification step S105 is performed, for example, when the flow rate (the amount of liquid-phase heating medium stored in the lower storage space 51B) of the heating medium that can be circulated by the heating and cooling pump 31 and delivered by the heating and cooling pump 31 to the first heat exchanger 11 becomes a certain amount or more. Figure 3 As shown, in the modification step S105, the second flow regulating valve 83 or the fifth flow regulating valve 86 is closed (changing from fully open or intermediate opening to fully closed), and the third flow regulating valve 84 or the fourth flow regulating valve 85 is opened (changing from fully closed to fully open or intermediate opening). This allows liquefied gas to be supplied from the liquefied gas storage device 21 to the first heat exchanger 11, and allows vaporized gas to be supplied from the first heat exchanger 11 to the gas supply destination 22. After performing the modification step S105, heat exchange between the liquefied gas and the heating medium for heating or cooling occurs in the first heat exchanger 11.

[0123] like Figure 3 As shown, in the turbine driving step S106, the turbine-side flow regulating valve 37 is opened (changing from fully closed to fully open or intermediate opening), and the turbine bypass-side flow regulating valve 38 is closed (changing from fully open or intermediate opening to fully closed). As a result, the heat medium for cooling and heating, pressurized by the cooling and heating pump 31 and heated in the second heat exchanger 14, is introduced into the cooling and heating turbine 32, driving the cooling and heating turbine 32 by the rotation of its turbine blades 322.

[0124] According to the above method, by using liquefied gas to cool the liquid-phase heating medium circulating in the gas-liquid separator 5, the heating / cooling pump 31, and the liquid return line 6 in the third heat exchanger 7 (cooling step S103), the proportion of the liquid-phase heating / cooling medium in the downstream side of the first heat exchanger 11 in the heat recovery cycle 3, including the gas-liquid separator 5 and the heating / cooling pump 31, can be increased at an earlier stage. By increasing the proportion of the liquid-phase heating / cooling medium in the heating / cooling pump 31, the capacity reduction caused by cavitation of the heating / cooling pump 31 can be suppressed, thus enabling the heating / cooling pump 31 to operate at an earlier stage. As a result, the heat recovery system 1 can be transitioned to stable operation at an earlier stage.

[0125] Furthermore, according to the above method, since heat exchange in the first heat exchanger 11 is not performed until the flow rate of the heating medium supplied to the first heat exchanger 11 reaches a large flow rate that does not cause blockage of the first heat exchanger 11, blockage of the first heat exchanger 11 when the heat recovery system 1 is started can be suppressed.

[0126] like Figure 1 As shown, the heat recovery system 1 according to several embodiments includes the first heat exchanger 11, the second heat exchanger 14, the heat recovery cycle 3, the gas-liquid separator 5, the liquid return pipeline 6, and the third heat exchanger 7.

[0127] According to the above structure, by using liquefied gas to cool the liquid-phase heating medium circulating in the gas-liquid separator 5, the heating / cooling pump 31, and the liquid return line 6 in the third heat exchanger 7, the proportion of the liquid-phase heating / cooling medium in the downstream side of the first heat exchanger 11 in the heat recovery cycle 3, including the gas-liquid separator 5 and the heating / cooling pump 31, can be increased at an earlier stage. By increasing the proportion of the liquid-phase heating / cooling medium in the heating / cooling pump 31, the capacity reduction caused by cavitation of the heating / cooling pump 31 can be suppressed, thus enabling the heating / cooling pump 31 to operate at an earlier stage. As a result, the heat recovery system 1 can be transitioned to stable operation at an earlier stage.

[0128] Furthermore, according to the above structure, heat exchange in the first heat exchanger 11 is not performed until the flow rate of the heating medium supplied to the first heat exchanger 11 reaches a large flow rate that does not cause blockage of the first heat exchanger 11, thereby suppressing blockage of the first heat exchanger 11 when the heat recovery system 1 is started.

[0129] like Figure 1 As shown, in several embodiments, the heat recovery system 1 includes the first flow regulating valve 35. According to this structure, by closing the first flow regulating valve 35, a closed loop including the gas-liquid separator 5, the heat pump 31, and the liquid return line 6 can be formed. By cooling the heat medium circulating in this closed loop with liquefied gas in the third heat exchanger 7, compared to cooling the heat medium circulating in the heat recovery cycle 3, which is wider than the closed loop, the internal temperature of the gas-liquid separator 5 can be rapidly reduced to below a predetermined temperature. Therefore, the heat recovery system 1 can be transitioned to stable operation earlier.

[0130] like Figure 1As shown, in several embodiments, the third heat exchanger 7 (7A) is configured to transfer the cooling energy of the liquefied gas extracted from the liquefied gas storage device 21 to the liquid-phase heating medium flowing in the liquid return line 6. According to this configuration, the third heat exchanger 7 (7A) can utilize the liquefied gas to cool the heating medium flowing in the liquid return line 6, thus rapidly reducing the internal temperature of the gas-liquid separator 5 to below a specified temperature. This allows the heat recovery system 1 to be transitioned to stable operation at an earlier stage.

[0131] Figures 4-8 These schematic diagrams illustrate the general structural features of a ship or buoy equipped with a heat recovery system according to one embodiment of the present invention.

[0132] like Figure 4 As shown, in several embodiments, the liquid return line 6 includes a first liquid return line 6A provided with a third heat exchanger 7 and a second liquid return line 6B that bypasses the third heat exchanger 7.

[0133] In the illustrated embodiment, one side (upstream end) of the first liquid return pipe 6A is connected to the connection portion P1 of the first lower connecting pipe 33C, and the other side (downstream end) of the first liquid return pipe 6A is connected to the liquid return port 55. One side (upstream end) of the second liquid return pipe 6B is connected to the branch portion P6 of the first liquid return pipe 6A located upstream of the third heat exchanger 7, and the other side (downstream end) of the second liquid return pipe 6B is connected to the confluence portion P7 of the first liquid return pipe 6A located downstream of the third heat exchanger 7.

[0134] like Figure 4 As shown, the liquid return line 6 may further include a first on / off valve 61 located between a branch P6 of the first liquid return line 6A and the third heat exchanger 7, and a second on / off valve 62 located in the second liquid return line 6B. By opening the first on / off valve 61 and fully closing the second on / off valve 62, the circulating hot / cold medium passes through the third heat exchanger 7. By fully closing the first on / off valve 61 and opening the second on / off valve 62, the circulating hot / cold medium passes through the second liquid return line 6B (bypassing the third heat exchanger 7).

[0135] During stable operation of the heat recovery system 1, the heat pump 31 is rotated at a stable rotational speed. Even after the valve opening step S104 is performed, the heat medium for heat recovery is circulated through the liquid return line 6.

[0136] According to the above structure, when the cooling of the hot and cold medium is not required by the third heat exchanger 7 (for example, during stable operation), the pressure loss in the third heat exchanger 7 can be suppressed by allowing the circulating hot and cold medium to pass through the second liquid return pipe 6B (bypassing the third heat exchanger 7). Therefore, the performance of the hot and cold recovery cycle 3 can be effectively utilized during the stable operation of the hot and cold recovery system 1.

[0137] like Figure 5 As shown, in several embodiments, the third heat exchanger 7 (7B) is configured to transfer the cold energy of the liquefied gas extracted from the liquefied gas storage device 21 to the hot and cold medium present inside the gas-liquid separator 5.

[0138] exist Figure 5 In the illustrated embodiment, the third heat exchanger 7 (7B) includes a third liquefied gas side flow path 73 disposed within the internal space 51 of the gas-liquid separator 5 for supplying liquefied gas flow. For example... Figure 5 As shown, the third liquefied gas side flow path 73 can be a pipeline in which liquefied gas can flow and whose outer surface faces the inner space 51.

[0139] The other side (downstream end) of the liquefied gas inlet pipe 81 is connected to the upstream end (gas inlet of the third heat exchanger 7) of the third liquefied gas side flow path 73. One side (upstream end) of the gas outlet pipe 82 is connected to the downstream end (gas outlet of the third heat exchanger 7) of the third liquefied gas side flow path 73. The temperature of the heating medium for heating and cooling existing in the internal space 51 is higher than the temperature of the liquefied gas flowing in the third liquefied gas side flow path 73.

[0140] In the third heat exchanger 7 (7B), the hot and cold heat medium existing in the internal space 51 exchanges heat with the liquefied gas flowing in the third liquefied gas side flow path 73, and the cold energy of the liquefied gas flowing in the third liquefied gas side flow path 73 is transferred to the hot and cold heat medium existing in the internal space 51. As a result, the hot and cold heat medium existing in the internal space 51 is cooled.

[0141] According to the above structure, the liquefied gas can be used to cool the hot and cold heat medium inside the gas-liquid separator 5, thereby rapidly reducing the internal temperature of the gas-liquid separator 5 to below a specified temperature. This allows the heat recovery system 1 to be transitioned to stable operation at an earlier stage.

[0142] like Figure 1 , Figure 4 , Figure 6 and Figure 7As shown, in several embodiments, the gas supply destination 22 includes the main engine 22A of the ship 2A or the float 2B. The main engine 22A is configured to utilize the energy of the supplied vaporized gas to generate a driving force (propulsion force) to drive a propeller or other thruster (not shown). The vaporized gas supply line 13 includes a fuel supply line 13A for supplying the main engine 22A of the ship 2A or the float 2B with liquefied gas vaporized in the first heat exchanger 11.

[0143] exist Figure 1 , Figure 4 In the illustrated embodiment, the gas discharge line 82 (82A) includes a flow path for guiding the vaporized gas, formed by vaporizing liquefied gas, from the third heat exchanger 7 to the main engine 22A. In this case, the vaporized gas that has passed through the third heat exchanger 7 is guided to the main engine 22A via the gas discharge line 82 (82A) and the like.

[0144] exist Figure 6 , Figure 7 In the illustrated embodiment, the gas discharge line 82 includes a start-up gas supply line 82B for guiding vaporized gas, formed from liquefied gas, from the third heat exchanger 7 to the gas combustion device 23, which is separately configured from the main engine 22A. The gas combustion device 23 is configured to combust the supplied gas. One side (downstream end) of the start-up gas supply line 82B is connected to the gas inlet of the gas combustion device 23.

[0145] exist Figure 6 In the illustrated embodiment, during startup, the other side (upstream end) of the gas supply line 82B is connected to the downstream end (gas outlet of the third heat exchanger 7) of the second liquefied gas side flow path 72. Figure 7 In the embodiment shown, during startup, the other side (upstream end) of the gas supply line 82B is connected to the downstream end (gas outlet of the third heat exchanger 7) of the third liquefied gas side flow path 73.

[0146] When the heat recovery system 1 is started, due to the small flow rate of the heat-using medium circulating in the heat recovery cycle 3, the liquefied gas may be supplied to the main engine 22A without being fully vaporized, which may lead to malfunction or poor actuation of the main engine 22A. According to Figure 6 , Figure 7 The structure shown allows the vaporized gas or liquefied gas to be guided to the gas combustion device 23 via the start-up gas supply line 82B when the heat recovery system 1 is started, and to be burned in the gas combustion device 23. This prevents the liquefied gas from being supplied to the main engine 22A without sufficient vaporization, thus preventing malfunctions or poor actuation of the main engine 22A. Furthermore, according to... Figure 6 , Figure 7The structure shown eliminates the need for complete vaporization of the liquefied gas in the third heat exchanger 7 during startup of the heat recovery system 1, thus enabling early activation of the heat recovery cycle 3 or the external water pump 45. This allows the heat recovery system 1 to transition to stable operation from an earlier stage.

[0147] (Bypass piping for the second heat exchanger)

[0148] like Figure 8 As shown, in several embodiments, the heat recovery system 1 can be configured such that, when the external water pump 45 is in operation, heat exchange between the heat transfer medium in the second heat exchanger 14 and the external water is not required. In the illustrated embodiment, the heat recovery system 1 further includes a heat exchanger-side bypass pipe 46 that bypasses the second heat exchanger 14 and connects the external water supply pipe 42 to the external water discharge pipe 44. One side (upstream end) of the heat exchanger-side bypass pipe 46 is connected to a branch P8 of the external water supply pipe 42. The other side (downstream end) of the heat exchanger-side bypass pipe 46 is connected to a junction P9 of the external water discharge pipe 44.

[0149] The aforementioned heat recovery system 1 may further include: a first external water-side on / off valve 47, located downstream of a branch P8 of the external water supply pipeline 42; and a second external water-side on / off valve 48, located in the heat exchanger-side bypass pipeline 46. By opening the first external water-side on / off valve 47 and completely closing the second external water-side on / off valve 48, external water flows through the second heat exchanger 14. By completely closing the first external water-side on / off valve 47 and opening the second external water-side on / off valve 48, external water flows through the heat exchanger-side bypass pipeline 46 (bypassing the second heat exchanger 14).

[0150] The time required from the start of driving the external water pump 45 to its transition to a stable state is significant. During this period, the flow rate of external water supplied to the second heat exchanger 14 is unstable, potentially causing instability in the heating of the heat transfer medium in the second heat exchanger 14. By allowing external water to flow through the heat exchanger-side bypass pipe 46 during the transition of the external water pump 45 to a stable state, stable operation can be achieved when the heat recovery system 1 transitions to stable operation. In the aforementioned start-up method 100 for the heat recovery system 1, external water can also be flowd through the heat exchanger-side bypass pipe 46 for a predetermined period starting from the start of the external water pump driving step S107. The valve opening step S104 can also be initiated during this predetermined period.

[0151] Alternatively, the heat recovery system 1 can also have a bypass line instead of the heat exchanger side bypass line 46, which bypasses the second heat exchanger 14 and connects the downstream part of the connection P1 of the first lower section connecting line 33C to the upstream part of the branch P2 of the second upper section connecting line 34A.

[0152] (Control device)

[0153] Figure 9 This is an explanatory diagram illustrating a control device for a heat recovery system according to one embodiment of the present invention. In several embodiments, such as Figure 9 As shown, the heat recovery system 1 further includes: a temperature acquisition device (a temperature sensor in the example) 87, configured to acquire the temperature of the heat transfer medium inside the gas-liquid separator 5; and a valve opening control device 88, which controls the opening of the second flow regulating valve 83 to ensure that the temperature of the heat transfer medium acquired by the temperature acquisition device 87 falls within a specified range. By increasing the opening of the second flow regulating valve 83 by the valve opening control device 88, the flow rate of liquefied gas supplied to the third heat exchanger 7 can be increased, thereby correspondingly cooling the interior of the gas-liquid separator 5.

[0154] In the illustrated embodiment, a valve opening control device 88 is mounted on a control device 9, which is configured to control the operation of the pumps included in the heat recovery system 1 and the opening of the valves included in the heat recovery system 1. The pumps included in the heat recovery system 1 (such as the heat pump 31) are configured to be driven or stopped according to the operation instructions of the control device 9. The valves included in the heat recovery system 1 (such as the first flow regulating valve 35) are configured to adjust their opening according to the opening instructions of the control device 9. The heat recovery system 1 includes a control device 9. Furthermore, several steps in the start-up method 100 can be performed by the control device 9. Also, the steps in the start-up method 100 can be performed using devices or equipment other than the control device 9, or manually.

[0155] Control device 9 is an electronic control unit used to control the heat recovery system 1. Control device 9 is configured as a microcomputer consisting of a CPU (processor) (not shown), a memory such as ROM or RAM, an external storage device, an I / O interface, a communication interface, etc. Control device 9 can, for example, perform actions (e.g., data operations) according to commands (such as data processing) from programs loaded into the main storage device of the aforementioned memory via the CPU to achieve control in valve opening control device 88.

[0156] According to the above structure, the valve opening control device 88 controls the opening of the second flow regulating valve 83 to maintain the temperature of the hot and cold medium obtained by the temperature acquisition device 87 within a specified range. This can suppress the capacity reduction caused by cavitation of the hot and cold pump 31 at an early stage, and can stabilize the temperature of the hot and cold medium flowing in the repeated circulation or hot and cold recovery circulation 3, which includes the gas-liquid separator 5, the hot and cold pump 31, and the liquid return pipeline 6, at an early stage. As a result, the valve opening step S104 and the change step S105 can be executed at an early stage, thus enabling the hot and cold recovery system 1 to enter stable operation at an early stage.

[0157] The present invention is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments or appropriate combinations thereof.

[0158] The contents described in the above embodiments can be understood, for example, as follows.

[0159] 1) The heat recovery system (1) according to at least one embodiment of the present invention is a heat recovery system (1) installed on a ship (2A) or a floating body (2B) having a liquefied gas storage device (21) configured to store liquefied gas, and includes:

[0160] The first heat exchanger (11) is configured to transfer cold energy from the liquefied gas extracted from the liquefied gas storage device (21) to a heat medium for heating and cooling.

[0161] The heat recovery cycle (3) is configured to circulate the heat medium and includes at least a heat pump (31) for conveying the heat medium, which is located downstream of the first heat exchanger (11).

[0162] The second heat exchanger (14) is configured to transfer heat energy from the heat carrier to the heat medium flowing downstream of the heat pump (31) in the heat recovery cycle (3) and upstream of the first heat exchanger (11).

[0163] A gas-liquid separator (5) is disposed between the first heat exchanger (11) and the cold and heat pump (31) in the cold and heat recovery cycle (3), and is configured to separate the cold and heat heat medium into a gas phase cold and heat heat medium and a liquid phase cold and heat heat medium.

[0164] A liquid return line (6) is used to return the liquid-phase heating medium from the downstream side of the heating pump (31) and the upstream side of the second heat exchanger (14) in the heating and cooling recovery cycle (3) to the gas-liquid separator (5); and

[0165] The third heat exchanger (7) is configured to transfer the cold energy of the liquefied gas extracted from the liquefied gas storage device (21) to either the liquid phase heating medium that returns to the gas-liquid separator (5) via the liquid return line (6) or the heating medium that exists inside the gas-liquid separator (5).

[0166] Based on the structure described in 1), by using liquefied gas to cool the liquid-phase heating medium circulating in the gas-liquid separator (5), the heating and cooling pump (31), and the liquid return line (6) in the third heat exchanger (7), the proportion of the liquid-phase heating medium in the downstream side of the first heat exchanger (11) in the heat recovery cycle (3) including the gas-liquid separator (5) and the heating and cooling pump (31) can be increased at an early stage. By increasing the proportion of the liquid-phase heating and cooling medium in the heating and cooling pump (31), the capacity reduction caused by cavitation of the heating and cooling pump (31) can be suppressed, and thus the capacity of the heating and cooling pump (31) can be utilized at an early stage. As a result, the heat recovery system (1) can be transitioned to stable operation at an early stage.

[0167] Furthermore, according to the structure of 1) above, heat exchange in the first heat exchanger (11) is not performed until the flow rate of the heat medium supplied to the first heat exchanger (11) reaches a large flow rate that does not cause blockage of the first heat exchanger (11), thereby suppressing blockage of the first heat exchanger (11) when the heat recovery system 1 is started.

[0168] 2) In several embodiments, according to the heat recovery system (1) described in 1) above, wherein,

[0169] The third heat exchanger (7) is configured to transfer the cold energy of the liquefied gas extracted from the liquefied gas storage device (21) to the liquid phase hot and cold medium flowing in the liquid return line (6).

[0170] Based on the structure described in 2), the liquefied gas can be used to cool the hot and cold medium flowing in the liquid return line (6) via the third heat exchanger (7), thus rapidly reducing the internal temperature of the gas-liquid separator (5) to below the specified temperature. As a result, the heat recovery system (1) can be transitioned to stable operation at an earlier stage.

[0171] 3) In several embodiments, according to the heat recovery system (1) described in 1) above, wherein,

[0172] The third heat exchanger (7) is configured to transfer the cold energy of the liquefied gas extracted from the liquefied gas storage device (21) to the hot medium for heating and cooling that exists inside the gas-liquid separator (5).

[0173] According to the structure described in 3), the liquefied gas can be used to cool the hot and cold heat medium inside the gas-liquid separator (5) through the third heat exchanger (7), thus rapidly reducing the temperature inside the gas-liquid separator (5) to below the specified temperature. As a result, the heat recovery system (1) can be switched to stable operation at an early stage.

[0174] 4) In several embodiments, according to the heat recovery system (1) described in 2) above, wherein,

[0175] The liquid return pipeline (6) includes:

[0176] The first liquid return line (6A) is equipped with the third heat exchanger (7); and

[0177] The second liquid return line (6B) bypasses the third heat exchanger (7).

[0178] According to the structure of 4) above, when the cooling of the hot and cold medium is not required by the third heat exchanger (7), the pressure loss in the third heat exchanger (7) can be suppressed by allowing the circulating hot and cold medium to pass through the second liquid return pipeline (6B) (bypassing the third heat exchanger (7)). Therefore, the performance of the hot and cold recovery cycle (3) can be effectively utilized when the hot and cold recovery system (1) is running stably.

[0179] 5) In several embodiments, the heat recovery system (1) according to any one of 1) to 4) above further comprises:

[0180] A fuel supply line (13A) is provided for supplying the liquefied gas, vaporized in the first heat exchanger (11), to the main engine (22A) of the vessel (2A) or the buoy (2B); and

[0181] At startup, a gas supply line (82B) is used to guide the vaporized gas formed by the vaporization of the liquefied gas from the third heat exchanger (7) to a gas combustion device (23) that is separately formed from the main engine (22A).

[0182] When the heat recovery system (1) is started, the flow rate of the heat medium circulating in the heat recovery cycle (3) is small, so the liquefied gas is supplied to the main engine (22A) without being fully vaporized, which may cause the main engine (22A) to malfunction or fail to operate. According to the structure of 5) above, when the heat recovery system (1) is started, the vaporized gas or liquefied gas can be guided to the gas combustion device (23) through the start-up gas supply line (82B) and burned in the gas combustion device (23). As a result, the supply of liquefied gas to the main engine (22A) without being fully vaporized can be suppressed, thus suppressing the malfunction or failure to operate of the main engine (22A). Furthermore, according to the structure of 5) above, when the heat recovery system (1) is started, it is not necessary to completely vaporize the liquefied gas in the third heat exchanger (7), so the heat recovery cycle 3 or the external water pump 45 can be driven from an early stage. As a result, the heat recovery system (1) can be transferred to stable operation from an early stage.

[0183] 6) In several embodiments, the heat recovery system (1) according to any one of 1) to 5) above further includes a first flow regulating valve (35), which is disposed between the connection (P1) at the upstream end of the liquid return pipeline (6) in the heat recovery cycle (3) and the second heat exchanger (14), and is configured to adjust the flow rate of the liquid phase heat medium for heat recovery guided to the second heat exchanger (14).

[0184] Based on the structure described in 6), by closing the first flow regulating valve (35), a closed loop can be formed, including the gas-liquid separator (5), the heating / cooling pump (31), and the liquid return line (6). By using liquefied gas to cool the heating / cooling medium circulating in this closed loop in the third heat exchanger (7), compared to the case where the heating / cooling medium circulates in a heating / cooling recovery cycle (3) that is wider than the closed loop, the internal temperature of the gas-liquid separator (5) can be rapidly reduced to below the specified temperature. As a result, the heating / cooling recovery system (1) can be transitioned to stable operation at an earlier stage.

[0185] 7) In several embodiments, the heat recovery system (1) according to any one of 1) to 6) above further comprises:

[0186] A liquefied gas inlet pipe (81) connects the liquefied gas storage device (21) to the third heat exchanger (7);

[0187] The second flow regulating valve (83) is provided in the liquefied gas inlet pipe (81) and is configured to regulate the flow rate of the liquefied gas guided to the third heat exchanger;

[0188] Temperature acquisition device (87) is configured to acquire the temperature of the heating medium for heating and cooling within the gas-liquid separator (5); and

[0189] The valve opening control device (88) controls the opening of the second flow regulating valve (83) so that the temperature of the heating medium for heating and cooling obtained by the temperature acquisition device (87) falls within a specified range.

[0190] According to the structure of 7) above, the opening of the second flow regulating valve (83) is controlled by the valve opening control device (88) to maintain the temperature of the hot and cold medium obtained by the temperature acquisition device (87) within a specified range. This can suppress the capacity reduction caused by cavitation of the hot and cold pump (31) in the early stage, and can stabilize the temperature of the hot and cold medium flowing in the repeated circulation or hot and cold recovery cycle (3) including the gas-liquid separator (5), the hot and cold pump (31) and the liquid return pipeline (6) in the early stage. As a result, the hot and cold recovery system (1) can be transferred to stable operation in the early stage.

[0191] 8) The start-up method (100) of the heat recovery system according to at least one embodiment of the present invention is a start-up method (100) of the heat recovery system (1) installed on a ship (2A) or a floating body (2B) having a liquefied gas storage device (21) configured to store liquefied gas.

[0192] The heat recovery system (1) includes:

[0193] The first heat exchanger (11) is configured to transfer cold energy from the liquefied gas extracted from the liquefied gas storage device (21) to a heat medium for heating and cooling.

[0194] The heat recovery cycle (3) is configured to circulate the heat medium and includes at least a heat pump (31) for conveying the heat medium, located downstream of the first heat exchanger (11); and

[0195] The second heat exchanger (14) is configured to transfer heat energy from the heat carrier to the heat transfer medium flowing downstream of the heat pump (31) in the heat recovery cycle (3) and upstream of the first heat exchanger (11).

[0196] The startup method (100) of the heat recovery system includes the following steps:

[0197] In the gas-liquid separation step (S101), the gas-liquid separator (5) located between the first heat exchanger (11) and the cold and heat pump (31) in the cold and heat recovery cycle (3) separates the cold and heat heat medium into a gas phase cold and heat heat medium and a liquid phase cold and heat heat medium.

[0198] In the circulation step (S102), the heating and cooling pump (31) is driven to return the liquid phase heating and cooling medium separated in the gas-liquid separation step (S101) to the gas-liquid separator (5) via the liquid return pipe (6), which is connected downstream of the heating and cooling pump (31) in the heating and cooling recovery cycle (3) and upstream of the second heat exchanger (14) to the gas-liquid separator (5); and

[0199] In the cooling step (S103), the cold energy of the liquefied gas extracted from the liquefied gas storage device (21) is transferred to either the liquid phase heating medium for cooling and heating that returns to the gas-liquid separator (5) via the liquid return pipe (6) in the circulation step (S102), or the heating medium for cooling and heating that exists inside the gas-liquid separator (5), and is then cooled.

[0200] According to the method described in 8), by using liquefied gas to cool the liquid-phase heating medium circulating in the gas-liquid separator (5), the heating and cooling pump (31), and the liquid return line (6) (cooling step S103), the proportion of the liquid-phase heating medium in the downstream side of the first heat exchanger (11) in the heat recovery cycle (3) including the gas-liquid separator (5) and the heating and cooling pump (31) can be increased at an earlier stage. By increasing the proportion of the liquid-phase heating medium in the heating and cooling pump (31), the capacity reduction caused by cavitation of the heating and cooling pump (31) can be suppressed, and thus the capacity of the heating and cooling pump (31) can be utilized at an earlier stage. As a result, the heat recovery system (1) can be transitioned to stable operation at an earlier stage.

[0201] Furthermore, according to the method described in 8), since heat exchange in the first heat exchanger (11) is not performed until the flow rate of the heat medium supplied to the first heat exchanger (11) reaches a large flow rate that does not cause blockage of the first heat exchanger (11), blockage of the first heat exchanger (11) when the heat recovery system 1 is started can be suppressed.

[0202] Symbol Explanation

[0203] 1-Heat and cold recovery system, 2A-Ship, 2B-Floating body, 3-Heat and cold recovery cycle, 5-Gas-liquid separator, 6-Liquid return pipeline, 7-Third heat exchanger, 9-Control device, 11-First heat exchanger, 12-Liquefied gas supply pipeline, 13-Vacuum gas supply pipeline, 13A-Fuel supply pipeline, 14-Second heat exchanger, 15-Liquefied gas pump, 21-Liquefied gas storage device, 22-Gas supply destination, 22A-Main engine, 31-Heat and cold recovery system Pump, 32-Heating / cooling turbine, 33-First connecting pipe, 33A-First upper connecting pipe, 33B-First middle connecting pipe, 33C-First lower connecting pipe, 34-Second connecting pipe, 34A-Second upper connecting pipe, 34B-Second lower connecting pipe, 35-First flow regulating valve, 36-Turbine bypass pipe, 37-Turbine side flow regulating valve, 38-Turbine bypass side flow regulating valve, 41-External water supply source, 42-External water supply pipe, 4 3-Destination of external water discharge, 44-External water discharge pipeline, 45-External water pump, 46-Bypass pipeline on the heat exchanger side, 47-First external water side on / off valve, 48-Second external water side on / off valve, 51-Internal space, 51A-Upper storage space, 51B-Lower storage space, 52-Main body, 53-Inlet, 54-Liquid phase outlet, 55-Liquid return outlet, 61-First on / off valve, 62-Second on / off valve, 81-Liquefied gas inlet pipeline, 8 2-Gas discharge pipeline, 83-Second flow regulating valve, 84-Third flow regulating valve, 85-Fourth flow regulating valve, 86-Fifth flow regulating valve, 87-Temperature acquisition device, 88-Valve opening control device, 100-Start-up method, S101-Gas-liquid separation step, S102-Circulation step, S103-Cooling step, S104-Valve opening step, S105-Change step, S106-Turbine drive step for heating and cooling, S107-Pump drive step for external water.

Claims

1. A heat recovery system installed on a ship or buoy having a liquefied gas storage device configured for storing liquefied gas, the heat recovery system comprising: The first heat exchanger is configured to transfer cold energy from the liquefied gas extracted from the liquefied gas storage device to a heat medium for heating and cooling. The heat recovery cycle is configured to circulate the heat medium and includes at least a heat pump for conveying the heat medium, located downstream of the first heat exchanger. The second heat exchanger is configured to transfer heat energy from a heat carrier to the heat medium flowing downstream of the heat pump in the heat recovery cycle and upstream of the first heat exchanger. A gas-liquid separator is disposed between the first heat exchanger and the cold and heat pump in the cold and heat recovery cycle, and is configured to separate the cold and heat heat medium into a gas phase cold and heat heat medium and a liquid phase cold and heat heat medium. A liquid return line is provided for returning the liquid-phase heating medium from the downstream side of the heating pump in the heating and cooling recovery cycle and the upstream side of the second heat exchanger to the gas-liquid separator; and The third heat exchanger is configured to transfer the cold energy of the liquefied gas extracted from the liquefied gas storage device to either the liquid phase heating medium that returns to the gas-liquid separator via the liquid return line, or the heating medium that exists inside the gas-liquid separator.

2. The heat recovery system according to claim 1, wherein, The third heat exchanger is configured to transfer the cold energy of the liquefied gas extracted from the liquefied gas storage device to the liquid phase heating medium flowing in the liquid return line.

3. The heat recovery system according to claim 1, wherein, The third heat exchanger is configured to transfer the cold energy of the liquefied gas extracted from the liquefied gas storage device to the hot medium for heating and cooling that exists inside the gas-liquid separator.

4. The heat recovery system according to claim 2, wherein, The liquid return pipeline includes: The first liquid return pipeline is equipped with the third heat exchanger; and The second liquid return line bypasses the third heat exchanger.

5. The heat recovery system according to any one of claims 1 to 4, further comprising: A fuel supply line for supplying the liquefied gas, vaporized in the first heat exchanger, to the main engine of the vessel or the buoy; and The gas supply line at startup is used to guide at least one of the liquefied gas or the gasified gas formed by the vaporization of the liquefied gas from the third heat exchanger to the gas combustion device which is separate from the main engine.

6. The heat recovery system according to any one of claims 1 to 4, further comprising a first flow regulating valve, the first flow regulating valve being disposed between the connection between the upstream end of the liquid return pipeline in the heat recovery cycle and the second heat exchanger, configured to adjust the flow rate of the liquid phase heat medium being guided to the second heat exchanger.

7. The heat recovery system according to any one of claims 1 to 4, further comprising: A liquefied gas inlet pipeline connects the liquefied gas storage device to the third heat exchanger; The second flow regulating valve is provided in the liquefied gas inlet pipeline and is configured to adjust the flow rate of the liquefied gas guided to the third heat exchanger; The temperature acquisition device is configured to acquire the temperature of the hot and cold heat medium inside the gas-liquid separator. and A valve opening control device controls the opening of the second flow regulating valve so that the temperature of the heating medium for heating or cooling, as obtained by the temperature acquisition device, falls within a specified range.

8. A method for starting a heat recovery system, said heat recovery system being installed on a ship or buoy having a liquefied gas storage device configured to store liquefied gas. The heat recovery system includes: The first heat exchanger is configured to transfer cold energy from the liquefied gas extracted from the liquefied gas storage device to a heat medium for heating and cooling. The heat recovery cycle is configured to circulate the heat medium and includes at least a heat pump for conveying the heat medium, located downstream of the first heat exchanger. and The second heat exchanger is configured to transfer heat energy from a heat carrier to the heating medium flowing downstream of the heating pump in the heat recovery cycle and upstream of the first heat exchanger. The startup method of the heat recovery system includes the following steps: In the gas-liquid separation step, a gas-liquid separator located between the first heat exchanger and the cold and heat pump in the cold and heat recovery cycle separates the cold and heat heat medium into a gas phase cold and heat heat medium and a liquid phase cold and heat heat medium. In the circulation step, the heating and cooling pump is driven so that the liquid phase heating and cooling medium separated in the gas-liquid separation step is returned to the gas-liquid separator via a liquid return pipeline. The liquid return pipeline is connected to the downstream side of the heating and cooling pump in the heating and cooling recovery cycle and the upstream side of the second heat exchanger is connected to the gas-liquid separator. and The cooling step involves transferring and cooling either the liquid-phase heating medium that returns to the gas-liquid separator via the liquid return line during the circulation step, or the heating medium that exists inside the gas-liquid separator, to either the liquefied gas extracted from the gas storage device.

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