Cooling and heating recovery system and method for starting the cooling and heating recovery system

Abstract

To provide a cold recovery system capable of suppressing clogging of a heat exchanger at start of the cold recovery system, and a starting method for the cold recovery system.SOLUTION: A cold recovery system includes: a first heat exchanger configured to transfer cold energy from liquefied gas to a cold heating medium; a cold recovery cycle including a cold pump provided downstream of the first heat exchanger to transfer the cold heating medium; a first gas liquid separator provided between the first heat exchanger and the cold pump in the cold recovery cycle and configured to separate the cold heating medium into a gas phase and a liquid phase; a pump bypass line for extracting the gas phase cold heating medium from the first gas liquid separator and guiding the gas phase cold heating medium to a portion downstream of the cold pump and upstream of the first heat exchanger in the cold recovery cycle; and air blowing means for sending the gas phase cold heating medium to the first heat exchanger via the pump bypass line.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a cold heat recovery system for recovering the cold heat energy of liquefied gas, and a method for starting the cold heat recovery system.

Background Art

[0002] Liquefied gas (for example, liquefied natural gas) is liquefied for the purpose of transportation and storage, and when supplied to a supply destination such as city gas or a thermal power plant, it is heated and vaporized by a heat medium such as seawater. When vaporizing liquefied gas, it may be performed to recover the cold heat energy of the liquefied gas instead of discarding it into seawater (for example, Patent Document 1).

[0003] Patent Document 1 discloses a cold heat power generation cycle that recovers the cold heat energy of liquefied natural gas as electric power. As this cold heat power generation cycle, a secondary medium Rankine cycle method and the like are known (see Patent Document 1). The secondary medium Rankine cycle method is a method in which a secondary medium circulating in a closed loop is heated and evaporated using seawater as a heat source in an evaporator, the steam is introduced into a turbine for cold heat power generation to obtain power, and then cooled and condensed with liquefied natural gas.

[0004] It is difficult to provide onshore LNG bases corresponding to each supply destination of liquefied natural gas because it is costly in terms of securing land and the like. For this reason, a ship equipped with an LNG storage facility for storing liquefied natural gas and a regasification facility for regasifying liquefied natural gas is moored at sea, and the liquefied natural gas regasified by the ship is sent via a pipeline to an onshore supply destination or an offshore power gauge (floating power plant).

[0005] Since a ship has less expandability than onshore facilities, in order to mount a cold heat power generation facility, it is important to miniaturize the cold heat power generation system, particularly the heat exchanger. Examples of small heat exchangers include printed circuit heat exchangers (PCHEs) and plate heat exchangers.

Prior Art Documents

Patent Document

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] When one heat exchange target is at a lower temperature than the freezing point of the other heat exchange target, in heat exchange in a heat exchanger, one heat exchange target may solidify, and the solidified heat exchange target may adhere to the surface of the heat exchanger, potentially blocking the heat exchanger. Compared with large heat exchangers (for example, shell-and-tube heat exchangers), small heat exchangers have a higher risk of blockage, so there are problems with reliability.

[0008] In a thermoelectric power generation cycle, when cooling a secondary medium circulating in the thermoelectric power generation cycle in a heat exchanger with liquefied natural gas, the heat exchanger may freeze. Especially during startup of a thermoelectric power generation cycle where the flow rate of the secondary medium circulating in the thermoelectric power generation cycle is small, the temperature of the secondary medium drops compared to steady operation, so the heat exchanger is highly likely to freeze. To prevent freezing of the heat exchanger, it is conceivable to provide a heating line for preheating the liquefied natural gas supplied to the heat exchanger, but such a heating line is not preferable because it leads to an increase in the size and cost of the system equipped with the thermoelectric power generation cycle.

[0009] In addition, in order to prevent the freezing of the heat exchanger, it is conceivable to increase the flow rate of the secondary medium that circulates through the thermoelectric power generation cycle when the thermoelectric power generation cycle is started. However, when the thermoelectric power generation cycle is stopped, the secondary medium may vaporize in the thermoelectric power generation cycle due to heat input from the ambient air to the thermoelectric power generation cycle. For this reason, at the start of the thermoelectric power generation cycle, the proportion of the vapor phase secondary medium in the circulation pump for circulating the secondary medium is larger than that during the steady operation of the thermoelectric power generation cycle. If the circulation rate of the circulation pump for circulating the secondary medium is increased, there is a problem that the possibility of starting failure due to gas biting of the circulation pump increases at the start of the thermoelectric power generation cycle.

[0010] In view of the above circumstances, an object of at least one embodiment of the present disclosure is to provide a cold heat recovery system capable of suppressing blockage of a heat exchanger at the start of a cold heat recovery system, and a method for starting the cold heat recovery system.

Means for Solving the Problems

[0011] A cold heat recovery system according to an embodiment of the present disclosure is A cold heat recovery system installed on a ship or a floating body having a liquefied gas storage device configured to store liquefied gas, A first heat exchanger configured to transfer cold heat energy from the liquefied gas withdrawn from the liquefied gas storage device to a cold heat medium, A cold heat recovery cycle configured to circulate the cold heat medium, the cold heat recovery cycle including at least a cold heat pump for sending the cold heat medium provided downstream of the first heat exchanger, A first gas-liquid separator provided between the first heat exchanger and the cold heat pump in the cold heat recovery cycle and configured to separate the cold heat medium into a vapor-phase cold heat medium and a liquid-phase cold heat medium, A pump bypass line for extracting the vapor-phase cold heat medium from the first gas-liquid separator and guiding it to a downstream side of the cold heat pump and an upstream side of the first heat exchanger in the cold heat recovery cycle, Blowing means for sending the heat medium for cold and heat of the gas phase to the first heat exchanger via the pump bypass line.

[0012] A method for starting a cold and heat recovery system according to an embodiment of the present disclosure is A method for starting a cold and heat recovery system installed on a ship or a floating body having a liquefied gas storage device configured to store liquefied gas, The cold and heat recovery system is A first heat exchanger configured to transfer cold and heat energy from the liquefied gas withdrawn from the liquefied gas storage device to a heat medium for cold and heat, A cold and heat recovery cycle configured to circulate the heat medium for cold and heat, the cold and heat recovery cycle including a cold and heat pump for sending the heat medium for cold and heat provided downstream of the first heat exchanger, The method for starting the cold and heat recovery system is A gas-liquid separation step of separating the heat medium for cold and heat into a gas-phase heat medium for cold and heat and a liquid-phase heat medium for cold and heat by a gas-liquid separator provided between the first heat exchanger and the cold and heat pump in the cold and heat recovery cycle, A blowing step of sending the gas-phase heat medium for cold and heat separated in the gas-liquid separation step to the first heat exchanger by bypassing the cold and heat pump, A cooling step of sending the liquefied gas from the liquefied gas storage device to the first heat exchanger and cooling the gas-phase heat medium for cold and heat sent to the first heat exchanger in the blowing step with the liquefied gas, A cold and heat pump driving step of driving the cold and heat pump after the cooling step.

Advantages of the Invention

[0013] According to at least one embodiment of the present disclosure, there are provided a cold and heat recovery system capable of suppressing blockage of a heat exchanger during startup of the cold and heat recovery system, and a method for starting the cold and heat recovery system.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0015] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, but are merely illustrative examples. For example, expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" not only strictly represent such arrangements, but also represent a state of being relatively displaced with tolerances or with angles and distances that can obtain the same function. For example, expressions indicating that things such as "identical", "equal", and "homogeneous" are in an equal state shall represent not only a strictly equal state, but also a state in which there is a tolerance or a difference to the extent that the same function can be obtained. For example, expressions representing shapes such as a rectangular shape or a cylindrical shape shall represent not only the shapes such as a rectangular shape or a cylindrical shape in a geometrically strict sense, but also shapes including concavo-convex portions, chamfered portions, etc. within a range where the same effect can be obtained. On the other hand, the expressions "comprising", "including", or "having" for one component are not exclusive expressions excluding the existence of other components. Note that the same reference numerals may be given to the same configurations and the description may be omitted.

[0016] (Ship, floating body) FIG. 1 is a schematic configuration diagram schematically showing the configuration of a ship 2A or a floating body 2B including a cold heat recovery system 1 according to a first embodiment of the present disclosure. The cold heat recovery system 1 according to some embodiments is installed in the ship 2A or the floating body 2B as shown in FIG. 1. The ship 2A and the floating body 2B are structures that can float on water. The ship 2A and the floating body 2B have a liquefied gas storage device (for example, a liquefied gas tank) 21 configured to store liquefied gas and a cold heat recovery system 1. In the illustrated embodiment, the ship 2A and the floating body 2B have a propulsion device (not shown) such as a propeller and a propulsion device (not shown) configured to drive the propulsion device, and are structures configured to be self-propelled by driving the propulsion device. Note that the present disclosure is also applicable to a non-self-propelled structure in which the ship 2A and the floating body 2B do not have a propulsion device for self-propulsion.

[0017] (Cold heat recovery system) As shown in FIG. 1, the cold and 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 the vaporized gas generated by vaporizing the liquefied gas in the first heat exchanger 11, a cold and heat recovery cycle 3 configured to circulate the heat medium for cold and heat exchanged with the liquefied gas in the first heat exchanger 11, a second heat exchanger 14, and a first gas-liquid separator 5.

[0018] (Cold and Heat Recovery Cycle) The cold and heat recovery cycle 3 is configured to circulate the heat medium for cold and heat under an organic Rankine cycle. In the following description, the upstream side in the circulation direction of the heat medium for cold and heat in the cold and heat recovery cycle 3 may be simply referred to as the upstream side, and the downstream side in the above circulation direction may be simply referred to as the downstream side. The cold and heat recovery cycle 3 includes a cold and heat pump 31 for sending the heat medium for cold and heat, and a cold and heat turbine 32 configured to be driven by the heat medium for cold and heat. The cold and heat pump 31 is provided on the downstream side of the first heat exchanger 11 and on the upstream side of the second heat exchanger 14 in the cold and heat recovery cycle 3. The cold and heat turbine 32 is provided on the upstream side of the first heat exchanger 11 and on the downstream side of the second heat exchanger 14 in the cold and heat recovery cycle 3.

[0019] Hereinafter, liquefied natural gas (LNG) will be taken as a specific example of the liquefied gas supplied from the liquefied gas storage device 21 which is the supply source of the liquefied gas, and propane will be taken as a specific example of the heat medium for cold and heat circulating in the cold and heat recovery cycle 3 for explanation. However, the present disclosure is also applicable when a liquefied gas other than liquefied natural gas (liquefied petroleum gas, liquid hydrogen, etc.) is used as the liquefied gas supplied from the liquefied gas storage device 21. Further, the present disclosure is also applicable when a heat medium other than propane (for example, an organic medium) is used as the heat medium for cold and heat flowing through the cold and heat recovery cycle 3. Note that the heat medium for cold and heat has a lower boiling point and freezing point than water.

[0020] (First Heat Exchanger) The first heat exchanger (liquefied gas vaporizer, cold heat side condenser) 11 is configured to perform heat exchange between the liquefied gas sent from the liquefied gas supply line 12 and the cold heat medium flowing downstream of the cold heat turbine 32 and upstream of the cold heat pump 31 in the cold heat recovery cycle 3. In the illustrated embodiment, the first heat exchanger 11 includes a liquefied gas side flow path 111 through which the liquefied gas sent from the liquefied gas supply line 12 flows, and a first cold heat side flow path 112 through which the cold heat medium circulating in the cold heat recovery cycle 3 flows. The liquefied gas flowing through the liquefied gas side flow path 111 is at a lower temperature than the cold heat medium flowing through the first cold heat side flow path 112.

[0021] In the first heat exchanger 11, heat exchange is performed between the liquefied gas flowing through the liquefied gas side flow path 111 and the cold heat medium flowing through the first cold heat side flow path 112, and the cold heat energy of the liquefied gas flowing through the liquefied gas side flow path 111 is transmitted to the cold heat medium flowing through the first cold heat side flow path 112. As a result, the liquefied gas flowing through the liquefied gas side flow path 111 is heated and vaporized, and the cold heat medium flowing through the first cold heat side flow path 112 is cooled and condensed.

[0022] (Second Heat Exchanger) The second heat exchanger 14 (cold heat side evaporator) is configured to perform heat exchange between the external water (heat medium) introduced from outside the cold heat recovery system 1 and the cold heat medium flowing downstream of the cold heat pump 31 and upstream of the cold heat turbine 32 in the cold heat recovery cycle 3. In the illustrated embodiment, the second heat exchanger 14 includes a second cold heat side flow path 141 through which the cold heat medium flows, and a heat medium side flow path 142 through which the external water flows. The second cold heat side flow path 141 (second heat exchanger 14) is provided downstream of the cold heat pump 31 and upstream of the cold heat turbine 32 in the cold heat recovery cycle 3. The external water flowing through the heat medium side flow path 142 is at a higher temperature than the cold heat medium flowing through the second cold heat side flow path 141.

[0023] In the second heat exchanger 14, heat exchange is performed between the heat medium for cold heat flowing through the second cold heat side flow path 141 and the external water flowing through the heat medium side flow path 142, and the thermal energy of the external water flowing through the heat medium side flow path 142 is transferred to the heat medium for cold heat flowing through the second cold heat side flow path 141. As a result, the heat medium for cold heat flowing through the second cold heat side flow path 141 is heated and vaporized.

[0024] (Liquefied gas supply system) One side (upstream end) of the liquefied gas supply line 12 is connected to the liquefied gas storage device 21, and the other side (downstream end) of the liquefied gas supply line 12 is connected to the upstream end (gas inlet of the first heat exchanger 11) of the liquefied gas side flow path 111. One side (upstream end) of the vaporized gas supply line 13 is connected to the downstream end (liquefied gas outlet of the first heat exchanger 11) of the liquefied gas side flow path 111, and the other side (downstream end) of the vaporized gas supply line 13 is connected to the supply destination 22 of the vaporized gas. Note that the supply destination 22 of the vaporized gas may be a facility provided outside the ship 2A or the floating body 2B (for example, an onshore power generation facility or a gas storage facility), or a facility mounted on the ship 2A or the floating body 2B.

[0025] The cold heat recovery system 1 further includes a liquefied gas pump 15 provided in the liquefied gas supply line 12. The liquefied gas pump 15 has a rotor blade (not shown) provided in the liquefied gas supply line 12, and by rotating this rotor blade by power supplied to the liquefied gas pump 15 or the like, the liquefied gas is sent 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, the liquefied gas stored in the liquefied gas storage device 21 is extracted into the liquefied gas supply line 12 and sent through the liquefied gas supply line 12 to the liquefied gas side flow path 111 of the first heat exchanger 11. The vaporized gas generated by vaporizing the liquefied gas in the liquefied gas side flow path 111 of the first heat exchanger 11 is sent by the liquefied gas pump 15 through the vaporized gas supply line 13 to the supply destination 22 of the gas.

[0026] (External water supply system) The cooling and heating recovery system 1 further includes an external water supply line 42 for supplying external water to a heat exchanger (second heat exchanger 14) that uses the external water of the cooling and heating recovery system 1 as a heat medium from a supply source 41 of the external water, an external water discharge line 44 for discharging the external water discharged from the heat exchanger that uses the external water as a heat medium to a discharge destination 43 of the external water, and an external water pump 45 provided in the external water supply line 42.

[0027] One side (upstream end) of the external water supply line 42 is connected to the supply source 41 of the external water, and the other side (downstream end) of the external water supply line 42 is connected to the upstream end of the heat medium side flow path 142 (the heat medium inlet of the second heat exchanger 14). One side (upstream end) of the external water discharge line 44 is connected to the downstream end of the heat medium side flow path 142 (the heat medium outlet of the second heat exchanger 14), and the other side (downstream end) of the external water discharge line 44 is connected to the discharge destination 43 of the external water. The external water may be water that can heat the heat exchange target as a heat medium in the heat exchanger (water at a higher temperature than the heat exchange target), and may be normal temperature water. The external water is preferably water that is easily obtainable on the ship 2A or the floating body 2B (for example, seawater outside the ship or engine cooling water that has cooled the engine of the ship 2A).

[0028] The supply source 41 of the external water may be a water intake provided on the ship 2A or the floating body 2B for taking in external water (for example, seawater) from outside the ship 2A or the floating body 2B, or may be a facility (for example, a water storage tank) provided inside the ship 2A or the floating body 2B. Further, the discharge destination 43 of the external water may be a drain port provided on the ship 2A or the floating body 2B for discharging the external water to the outside of the ship 2A or the floating body 2B, or may be a facility (for example, a drain tank) provided inside the ship 2A or the floating body 2B.

[0029] The external water pump 45 has impellers (not shown) provided in the external water supply line 42, and by rotating these impellers by power supplied to the external water pump 45 or the like, it is configured to send 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 out from the external water supply source 41 into the external water supply line 42 and sent through the external water supply line 42 to a heat exchanger (the second heat exchanger 14) using the external water as a heat medium.

[0030] (Cooling heat medium circulation system) As shown in FIG. 1, the cooling heat recovery cycle 3 further includes a first connection line 33 and a second connection line (main line) 34. The first connection line 33 connects the downstream end of the first cooling heat side flow path 112 (the outlet of the cooling heat medium of the first heat exchanger 11) and the upstream end of the second cooling heat side flow path 141 (the inlet of the cooling heat medium of the second heat exchanger 14). The above-described cooling heat pump 31 is provided in the first connection line 33. The second connection line 34 connects the downstream end of the second cooling heat side flow path 141 (the outlet of the cooling heat medium of the second heat exchanger 14) and the upstream end of the first cooling heat side flow path 112 (the inlet of the cooling heat medium of the first heat exchanger 11). The above-described cooling heat turbine 32 is provided in the second connection line 34.

[0031] (First gas-liquid separator) The first gas-liquid separator 5 is configured to separate the cooling heat medium into a gas phase and a liquid phase. The first gas-liquid separator 5 is provided in the cooling heat recovery cycle 3 on the downstream side of the first cooling heat side flow path 112 (the first heat exchanger 11) and on the upstream side of the cooling heat pump 31. Specifically, the first gas-liquid separator 5 is provided on the upstream side of the cooling heat pump 31 in the first connection line 33.

[0032] The first gas-liquid separator 5 includes a main body 52 configured to define an internal space 51 into which the heat transfer medium for cooling and heating sent from the first cooling and heating side flow path 112 (first heat exchanger 11) is introduced through the first connection line 33, an inlet 53 for introducing the heat transfer medium for cooling and heating into the internal space 51, a liquid phase discharge port 54 for discharging the liquid-phase heat transfer medium for cooling and heating from the internal space 51 to the outside of the first gas-liquid separator 5, and a gas phase discharge port 55 for discharging the gas-phase heat transfer medium for cooling and heating from the internal space 51 to the outside of the first gas-liquid separator 5.

[0033] The internal space 51 includes a lower storage space 51B in which the liquid-phase heat transfer medium for cooling and heating is stored, and an upper storage space 51A provided above the lower storage space 51B and communicating with the lower storage space 51B, in which the gas-phase heat transfer medium for cooling and heating is stored. The liquid phase discharge port 54 communicates with the lower storage space 51B. The gas phase discharge port 55 communicates with the upper storage space 51A.

[0034] The above-described first connection line 33 includes a first upper connection line 33A connecting the downstream end of the first cooling and heating side flow path 112 and the inlet 53, a first middle connection line 33B connecting the liquid phase discharge port 54 and the pump inlet 311 of the cooling and heating pump 31, and a first lower connection line 33C connecting the pump outlet 312 of the cooling and heating pump 31 and the upstream end of the second cooling and heating side flow path 141.

[0035] The heat transfer medium for cooling and heating cooled by the first heat exchanger 11 is guided to the first gas-liquid separator 5 through the first upper connection line 33A. The heat transfer medium for cooling and heating flowing into the internal space 51 from the inlet 53 is separated into a liquid phase and a gas phase in the internal space 51.

[0036] (Cooling and heating pump) The cooling and heating pump 31 is configured to send the heat transfer medium for cooling and heating to the downstream side of the cooling and heating recovery cycle 3 (the side where the second heat exchanger 14 is located). The cooling and heating pump 31 has an impeller (not shown) provided in the first connection line 33, and by rotating this impeller by the power supplied to the cooling and heating pump 31 or the like, the liquid-phase heat transfer medium for cooling and heating is sent to the downstream side of the first connection line 33.

[0037] By driving the heat pump 31 for cooling and heating, the liquid-phase heat medium for cooling and heating stored in the lower storage space 51B is guided to the heat pump 31 for cooling and heating through the liquid-phase discharge port 54 and the first middle-stage connection line 33B and pressurized by the heat pump 31 for cooling and heating. The liquid-phase heat medium for cooling and heating pressurized by the heat pump 31 for cooling and heating is sent by the heat pump 31 for cooling and heating to the second cooling-side flow path 141 (the second heat exchanger 14) through the first lower-stage connection line 33C.

[0038] (Equipment related to the heat pump for cooling and heating) As shown in FIG. 1, the cooling and heating recovery cycle 3 may further include a liquid return line 35 for returning the liquid-phase heat medium for cooling and heating from a position downstream of the heat pump 31 for cooling and heating and upstream of the second heat exchanger 14 in the cooling and heating recovery cycle 3 to the first gas-liquid separator 5, and a first flow rate adjustment valve 36 provided between a connection portion P1 of the upstream end of the liquid return line 35 in the cooling and heating recovery cycle 3 and the second heat exchanger 14. The first flow rate adjustment valve 36 is configured to be able to adjust the flow rate of the liquid-phase heat medium for cooling and heating guided to the second heat exchanger 14.

[0039] In the illustrated embodiment, the first gas-liquid separator 5 further includes a liquid return port 56 for introducing the liquid-phase heat medium for cooling and heating from the liquid return line 35 into the internal space 51. The liquid return port 56 communicates with the internal space 51. One side (upstream end) of the liquid return line 35 is connected to the connection portion P1 of the first lower-stage connection line 33C, and the other side (downstream end) of the liquid return line 35 is connected to the liquid return port 56. The first flow rate adjustment valve 36 is provided downstream of the connection portion P1 of the first lower-stage connection line 33C. The first flow rate adjustment valve 36 can adjust the flow rate of the heat medium for cooling and heating supplied to the downstream side (the 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 heat medium for cooling and heating. Note that the first flow rate adjustment valve 36 may be an on-off valve whose opening can be adjusted between fully closed and fully open, or an opening adjustment valve whose opening can be adjusted between fully closed, fully open, and at least one intermediate opening therebetween.

[0040] (Turbine for cooling and heating) In the turbine 32 for cooling and heating, the heat medium for cooling and heating that has been pressurized by the pump 31 for cooling and heating and whose temperature has been raised in the second heat exchanger 14 is introduced as the working fluid. The turbine 32 for cooling and heating includes a rotating shaft 321, turbine blades 322 attached to the rotating shaft 321, and a casing 323 that rotatably houses the turbine blades 322. In the casing 323, an inlet 324 for introducing the heat medium for cooling and heating into the inside of the casing 323 and an outlet 325 for discharging the heat medium for cooling and heating that has passed through the turbine blades 322 to the outside of the casing 323 are formed. The turbine 32 for cooling and heating is configured to rotate the turbine blades 322 by the energy of the heat medium for cooling and heating introduced into the inside of the casing 323 through the inlet 324. The heat medium for cooling and heating that has passed through the turbine blades 322 is discharged to the outside of the casing 323 through the outlet 325.

[0041] The cooling and heating recovery cycle 3 is configured to recover the rotational force generated by the turbine blades 322 as power. In the illustrated embodiment, the cooling and heating recovery cycle 3 further includes a generator 326 for cooling and heating that is configured to generate electricity by driving the turbine 32 for cooling and heating. The generator 326 for cooling and heating is mechanically connected to the rotating shaft 321 and is configured to convert the rotational force of the turbine blades 322 into electric power. In some other embodiments, the cooling and heating recovery cycle 3 may recover the rotational force generated by the turbine blades 322 as power as it is by a power transmission device (for example, a coupling, a belt, a pulley, etc.) instead of converting it into electric power.

[0042] The above-described second connection line 34 includes a second upper connection line 34A that connects the downstream end of the second cooling and heating side flow path 141 and the inlet 324 of the turbine 32 for cooling and heating, and a second lower connection line 34B that connects the outlet 325 of the turbine 32 for cooling and heating and the upstream end of the first cooling and heating side flow path 112.

[0043] (Equipment related to the turbine for cooling and heating) As shown in FIG. 1, the cooling / heating recovery cycle 3 further includes a turbine bypass line 37 that connects the upstream side and the downstream side of the cooling / heating turbine 32 of the second connection line 34 by bypassing the cooling / heating turbine 32, a second flow rate adjustment valve 38, and a third flow rate adjustment valve 39.

[0044] One side (upstream end) of the turbine bypass line 37 is connected to the branch portion P2 of the second upper connection line 34A, and the other side (downstream end) of the turbine bypass line 37 is connected to the confluence portion P3 of the second lower connection line 34B. The second flow rate adjustment valve 38 is provided on the downstream side (on the side of the cooling / heating turbine 32) of the branch portion P2 of the second upper connection line 34A. The third flow rate adjustment valve 39 is provided on the turbine bypass line 37. Each of the second flow rate adjustment valve 38 and the third flow rate adjustment valve 39 can adjust the flow rate of the cooling / heating heat medium supplied to the downstream side of the valve body by moving a valve body (not shown) that opens and closes the flow path of the cooling / heating heat medium. Note that each of the second flow rate adjustment valve 38 and the third flow rate adjustment valve 39 may be an on-off valve whose opening degree can be adjusted between fully closed and fully open, or an opening degree adjustment valve whose opening degree can be adjusted between fully closed, fully open, and at least one intermediate opening degree therebetween.

[0045] For example, by opening the second flow rate adjustment valve 38 (fully open or intermediate opening degree) and closing the third flow rate adjustment valve 39, the cooling / heating heat medium can be sent to the first heat exchanger 11 via the cooling / heating turbine 32. Also, by closing the second flow rate adjustment valve 38 and opening the third flow rate adjustment valve 39 (fully open or intermediate opening degree), the cooling / heating heat medium can be sent to the first heat exchanger 11 via the turbine bypass line 37.

[0046] (Pump bypass line, blowing means) As shown in FIG. 1, a heat recovery system 1 according to some embodiments extracts a vapor-phase heat medium for cold heat from a first gas-liquid separator 5 and guides it to a position downstream of a cold-heat pump 31 and upstream of a first heat exchanger 11 in a cold-heat recovery cycle 3. The system further includes a pump bypass line 6 and a blowing means 7 for sending the vapor-phase heat medium for cold heat to the first heat exchanger 11 via the pump bypass line 6. By the blowing means 7, the vapor-phase heat medium for cold heat extracted from the first gas-liquid separator 5 to the pump bypass line 6 is sent to the first heat exchanger 11.

[0047] One side (upstream end) 61 of the pump bypass line 6 is connected to the vapor-phase discharge port 55 of the first gas-liquid separator 5, and the other side (downstream end) 62 of the pump bypass line 6 is connected to a position downstream of the first flow rate adjustment valve 36 of the first lower connection line 33C, either to the second connection line 34 or the turbine bypass line 37.

[0048] In the embodiment shown in FIG. 1, the other side (downstream end) 62 of the pump bypass line 6 is connected to a connection position P4 downstream of the first flow rate adjustment valve 36 of the first lower connection line 33C.

[0049] In the illustrated embodiment, the blowing means 7 includes a blower 7A provided downstream of the third flow rate adjustment valve 39 of the turbine bypass line 37. The blower 7A is configured to send the vapor-phase heat medium for cold heat to the downstream side of the turbine bypass line 37. In the illustrated embodiment, the blower 7A includes a rotating shaft 71, a moving blade 72 attached to the rotating shaft 71, a casing 73 that rotatably houses the moving blade 72, and an electric motor 74 configured to supply a driving force for rotating the moving blade 72 to the moving blade 72.

[0050] The moving blade 72 is arranged on the downstream side of the third flow rate adjusting valve 39 of the turbine bypass line 37. In the casing 73, an inlet 731 for introducing the gas-phase heat medium for cooling and heating into the inside of the casing 73 and an outlet 732 for discharging the gas-phase heat medium for cooling and heating that has passed through the moving blade 72 to the outside of the casing 73 are formed. The electric motor 74 is mechanically connected to the rotating shaft 71. The moving blade 72 rotates when the driving force generated by the electric motor 74 is transmitted via the rotating shaft 71.

[0051] (Starting method of the cooling and heating recovery system) FIG. 2 is a flowchart of a starting method of a cooling and heating recovery system according to an embodiment of the present disclosure. FIG. 3 is an explanatory diagram for explaining an example of control in a cooling and heating recovery system according to an embodiment of the present disclosure. As shown in FIGS. 2 and 3, the period from the start-up of the cooling and heating recovery system 1 to the steady operation of the cooling and heating recovery system 1 is divided into a first period (gas-phase circulation period) T1, a second period (phase transition period) T2, and a third period (liquid-phase circulation period) T3. The second period T2 is a period after the first period T1 and a period before the third period T3.

[0052] In the first period T1, the gas-phase heat medium for cooling and heating extracted from the first gas-liquid separator 5 in the cooling and heating recovery cycle 3 is circulated. In the third period T3, the liquid-phase heat medium for cooling and heating extracted from the first gas-liquid separator 5 in the cooling and heating recovery cycle 3 is circulated. In the second period T2, the heat medium for cooling and heating circulating in the cooling and heating recovery cycle 3 is changed from the gas phase (the gas phase extracted from the first gas-liquid separator 5) to the liquid phase (the liquid phase extracted from the first gas-liquid separator 5).

[0053] As shown in FIG. 2, the starting method 100 of the cooling and heating recovery system 1 according to some embodiments includes a gas-liquid separation step S101, a blowing step S102, a cooling step S103, and a heat medium pump driving step S104.

[0054] In the gas-liquid separation step S101, the heat medium for cooling and heating is separated into a gas phase and a liquid phase by the above-described first gas-liquid separator 5. The gas-liquid separation step S101 is continuously performed from the start-up of the cooling and heating recovery system 1 until the steady operation and during the steady operation.

[0055] Due to the heat input from the ambient air to the cooling and heating recovery cycle 3 and the first gas-liquid separator 5 when the cooling and heating recovery system 1 stops, the heat medium for cooling and heating may vaporize in the cooling and heating recovery cycle 3. Therefore, at the start-up of the cooling and heating recovery system 1, compared with the steady operation of the cooling and heating recovery system 1, the ratio of the gas-phase heat medium for cooling and heating in the cooling and heating recovery cycle 3, such as the first gas-liquid separator 5 and the cooling and heating pump 31, is larger than that on the downstream side of the first heat exchanger 11 and in the second heat exchanger 14. If the ratio of the gas-phase heat medium for cooling and heating in the cooling and heating pump 31 is large, there is a risk of capacity reduction due to gas entrainment in the cooling and heating pump 31.

[0056] In the air supply step S102, the gas-phase heat medium for cooling and heating separated in the gas-liquid separation step S101 is sent to the first heat exchanger 11 bypassing the cooling and heating pump 31. In the illustrated embodiment, by driving the above-described blower 7A (air supply means 7), the gas-phase heat medium for cooling and heating is extracted from the first gas-liquid separator 5 to the pump bypass line 6. The gas-phase heat medium for cooling and heating extracted by the blower 7A is sent by the blower 7A to the first cooling-side flow path 112 (first heat exchanger 11). The heat medium for cooling and heating sent to the first cooling-side flow path 112 is sent to the first gas-liquid separator 5 after passing through the first upper connection line 33A.

[0057] Specifically, the gas-phase heat medium for cooling and heating extracted from the first gas-liquid separator 5 by the blower 7A passes through the pump bypass line 6, downstream of the connection position P4 of the first lower connection line 33C, the second cooling-side flow path 141 (second heat exchanger 14), upstream of the branch portion P2 of the second upper connection line 34A, and downstream of the confluence portion P3 of the turbine bypass line 37 and the second lower connection line 34B, and then is sent to the first cooling-side flow path 112 (first heat exchanger 11).

[0058] The air supply step S102 starts in the first period T1 and continues until the second period T2. As shown in FIG. 3, in the first period T1 and the second period T2, the second flow rate adjustment valve 38 is fully closed and the third flow rate adjustment valve 39 is opened (fully opened or at an intermediate opening degree), so that the heat medium for cold heat is sent to the first heat exchanger 11 via the turbine bypass line 37.

[0059] In the cooling step S103, liquefied gas is sent from the liquefied gas storage device 21 to the first heat exchanger 11, and the gaseous heat medium for cold heat sent to the first heat exchanger 11 in the air supply step S102 is cooled by the liquefied gas. In the illustrated embodiment, by driving the liquefied gas pump 15, the liquefied gas is sent from the liquefied gas storage device 21 to the liquefied gas side flow path 111 (the first heat exchanger 11) via the liquefied gas supply line 12. The cooling step S103 starts after the air supply step S102 in the first period T1.

[0060] By cooling and condensing the gaseous heat medium for cold heat circulating in the cold heat recovery cycle 3 via the pump bypass line 6 with the liquefied gas in the first heat exchanger 11, the proportion of the liquid-phase heat medium for cold heat can be increased earlier at a position downstream of the first heat exchanger 11 and upstream of the second heat exchanger 14 in the cold heat recovery cycle 3 such as the first gas-liquid separator 5 and the cold heat pump 31. By increasing the proportion of the liquid-phase heat medium for cold heat in the cold heat pump 31, the reduction in capacity due to gas biting of the cold heat pump 31 can be suppressed, so that the capacity of the cold heat pump 31 can be exerted from an early stage.

[0061] In the cold and heat pump driving step S104, the cold and heat pump 31 is driven after the cooling step S103. As shown in FIG. 3, the driving of the cold and heat pump 31 is performed after the driving of the liquefied gas pump 15. At the start of the cold and heat pump driving step S104 (at the start of driving the cold and heat pump 31), it is preferable that the first flow rate adjustment valve 36 is fully closed. At the start of the cold and heat pump driving step S104, since there is a small amount of the cold and heat medium that can be sent to the first heat exchanger 11 by the cold and heat pump 31, it may cause blockage of the first heat exchanger 11.

[0062] With the first flow rate adjustment valve 36 in the fully closed state, by driving the cold and heat pump 31, the liquid-phase cold and heat medium circulates through the first gas-liquid separator 5, the cold and heat pump 31, and the liquid return line 35. Specifically, with the first flow rate adjustment valve 36 in the fully closed state, by driving the cold and heat pump 31, the liquid-phase cold and heat medium is withdrawn from the first gas-liquid separator 5 through the liquid-phase discharge port 54. The liquid-phase cold and heat medium withdrawn from the first gas-liquid separator 5 is sent to the first gas-liquid separator 5 after passing through the upstream side of the connection part P1 of the first middle connection line 33B, the cold and heat pump 31, the first lower connection line 33C, and the liquid return line 35 from the cold and heat pump 31.

[0063] In the illustrated embodiment, as shown in FIG. 2, the startup method 100 of the cold and heat recovery system 1 further includes an open valve step S105 of opening the first flow rate adjustment valve 36 (changing from fully closed to fully open or an intermediate opening degree) after the start of the cold and heat pump driving step S104 and sending the liquid-phase cold and heat medium to the second heat exchanger 14 by the cold and heat pump 31, a blower means stop step S106 of stopping the blower 7A (blower means 7) after the open valve step S105, a cold and heat turbine driving step S107 of guiding the cold and heat medium to the cold and heat turbine 32 and driving the cold and heat turbine 32 after the open valve step S105, and an external water pump driving step S108 of driving the external water pump 45 before the open valve step S105.

[0064] The valve opening step S105 is performed, for example, when the flow rate of the heat transfer medium for cooling and heating in the liquid phase circulated by the cooling and heating pump 31 (the storage amount of the heat transfer medium for cooling and heating in the liquid phase in the lower storage space 51B) reaches a certain amount or more and can be sent to the first heat exchanger 11 by the cooling and heating pump 31. The heat transfer medium for cooling and heating in the liquid phase that has passed through the first flow rate adjustment valve 36 is heated and vaporized in the second heat exchanger 14 and then sent to the first heat exchanger 11.

[0065] Specifically, the heat transfer medium for cooling and heating in the liquid phase that has passed through the first flow rate adjustment valve 36 passes through the downstream side of the first flow rate adjustment valve 36 in the first lower connection line 33C, the second cooling side flow path 141 (the second heat exchanger 14), the upstream side of the branch portion P2 in the second upper connection line 34A, and the downstream side of the confluence portion P3 of the turbine bypass line 37 and the second lower connection line 34B, and then is sent to the first cooling side flow path 112 (the first heat exchanger 11).

[0066] Before the valve opening step S105, the external water pump 45 is driven (S108), and external water is supplied to the heat transfer medium side flow path 142 of the second heat exchanger 14. The heat transfer medium for cooling and heating in the liquid phase that has passed through the first flow rate adjustment valve 36 is heated and vaporized by the external water (heat transfer medium) in the second heat exchanger 14. As shown in FIGS. 2 and 3, the driving of the external water pump 45 (S108) may be performed before the air blowing step S102. In this case, by heating the heat transfer medium for cooling and heating flowing through the second heat exchanger 14 by the external water via the pump bypass line 6, clogging in the first heat exchanger 11 can be suppressed.

[0067] In the above-described second period T2, by executing the cooling and heating pump driving step S104, the valve opening step S105, and the air blowing means stop step S106, the heat transfer medium for cooling and heating circulating in the cooling and heating recovery cycle 3 is changed from the gas phase (the gas phase extracted from the first gas-liquid separator 5) to the liquid phase (the liquid phase extracted from the first gas-liquid separator 5). The cooling and heating turbine driving step S107 is performed in the above-described third period T3. That is, the cooling and heating turbine driving step S107 is performed after the air blowing means stop step S106.

[0068] In the cold and heat turbine driving step S107, as shown in FIG. 3, the second flow rate adjustment valve 38 is opened (changed from fully closed to fully open or an intermediate opening degree), and the third flow rate adjustment valve 39 is closed (changed from fully open or an intermediate opening degree to fully closed). As a result, the cold and heat heat medium pressurized by the cold and heat pump 31 and heated up by the second heat exchanger 14 is introduced into the cold and heat turbine 32, and the turbine blades 322 of the cold and heat turbine 32 rotate, thereby driving the cold and heat turbine 32.

[0069] According to the above method, the gaseous cold and heat heat medium separated in the gas-liquid separation step S101 is sent to the first heat exchanger 11 by bypassing the cold and heat pump 31 (blowing step S102), so that the gaseous cold and heat heat medium can be circulated in the cold and heat recovery cycle 3. Since the gaseous cold and heat heat medium is less likely to cause blockage in the first heat exchanger 11 than the liquid-phase cold and heat heat medium, blockage of the first heat exchanger 11 at the start of the cold and heat recovery system 1 can be suppressed.

[0070] Also, according to the above method, the gaseous cold and heat heat medium circulating in the cold and heat recovery cycle 3 is cooled by the liquefied gas in the first heat exchanger 11 (cooling step S103) and condensed, so that the ratio of the liquid-phase cold and heat heat medium can be increased earlier on the downstream side of the first heat exchanger 11 in the cold and heat recovery cycle 3, such as the first gas-liquid separator 5 and the cold and heat pump 31. By increasing the ratio of the liquid-phase cold and heat heat medium in the cold and heat pump 31, a decrease in capacity due to gas biting of the cold and heat pump 31 can be suppressed, so that the cold and heat pump 31 can be driven earlier (cold and heat pump driving step S104), and the capacity of the cold and heat pump 31 can be exerted from an early stage. Thereby, the cold and heat recovery system 1 can be shifted to steady operation earlier.

[0071] As shown in FIG. 1, the cold and heat recovery system 1 according to some embodiments includes the above-described first heat exchanger 11, the above-described cold and heat recovery cycle 3, the above-described first gas-liquid separator 5, the above-described pump bypass line 6, and blowing means 7.

[0072] According to the above configuration, by the blowing means 7, the gaseous heat medium for cold heat separated by the first gas-liquid separator 5 is sent to the first heat exchanger 11 through the pump bypass line 6, so that the gaseous heat medium for cold heat can be circulated in the cold heat recovery cycle 3. Since the gaseous heat medium for cold heat is less likely to cause blockage in the first heat exchanger 11 than the liquid heat medium for cold heat, blockage of the first heat exchanger 11 at the start of the cold heat recovery system 1 can be suppressed.

[0073] Also, according to the above configuration, when starting the cold heat recovery system 1, the gaseous heat medium for cold heat circulating in the cold heat recovery cycle 3 is cooled and condensed by the liquefied gas in the first heat exchanger 11, so that the proportion of the liquid heat medium for cold heat can be increased earlier on the downstream side of the first heat exchanger 11 in the cold heat recovery cycle 3, such as the first gas-liquid separator 5 and the cold heat pump 31. By increasing the proportion of the liquid heat medium for cold heat in the cold heat pump 31, the reduction in capacity due to gas biting of the cold heat pump 31 can be suppressed, so that the capacity of the cold heat pump 31 can be exerted from the early stage. Thereby, the cold heat recovery system 1 can be shifted to steady operation earlier.

[0074] (Specific Example 1 of the Connection Position of the Pump Bypass Line) In some embodiments, as shown in FIG. 1, the above-described pump bypass line 6 is connected upstream of the second heat exchanger 14 in the cold heat recovery cycle 3. In this case, even if the cold heat pump 31 is driven and the liquid heat medium for cold heat is sent to the downstream side of the cold heat pump 31, since the liquid heat medium for cold heat vaporizes in the second heat exchanger 14, on the downstream side of the second heat exchanger 14, the gaseous heat medium for cold heat flows in the same manner as before driving the cold heat pump 31. Therefore, during the period from the start to the steady operation of the cold heat recovery system 1, the transient change of the heat medium for cold heat flowing downstream of the second heat exchanger 14 and upstream of the first heat exchanger 11 can be suppressed.

[0075] Also, according to the above configuration, even after driving the heat pump for cooling and heating 31, since the gaseous heat medium for cooling and heating flows on the downstream side of the second heat exchanger 14 and on the upstream side of the first heat exchanger 11, there is no need to suddenly stop the blowing means 7, and it is possible to gently shift the cooling and heating recovery cycle 3 to steady operation. Therefore, according to the above configuration, the reliability during the period from the start-up to the steady operation of the cooling and heating recovery system 1 can be improved.

[0076] (Specific Example 2 of the Connection Position of the Pump Bypass Line) FIG. 4 is a schematic configuration diagram schematically showing the configuration of a ship or a floating body provided with a cooling and heating recovery system according to a second embodiment of the present disclosure. In some embodiments, as shown in FIG. 4, the above-described pump bypass line 6 is connected on the downstream side of the second heat exchanger 14 and on the upstream side of the turbine for cooling and heating 32 in the cooling and heating recovery cycle 3.

[0077] In the embodiment shown in FIG. 4, the other side (downstream end) 62 of the pump bypass line 6 is connected to a connection position P5 upstream of the branch portion P2 of the second upper connection line 34A. In the embodiment shown in FIG. 4, in the above-described blowing step S102, the gaseous heat medium for cooling and heating extracted from the first gas-liquid separator 5 by the blower 7A passes through the pump bypass line 6, between the connection position P5 and the branch portion P2 of the second upper connection line 34A, and downstream of the confluence portion P3 of the turbine bypass line 37 and the second lower connection line 34B, and then is sent to the first cooling and heating side flow path 112 (the first heat exchanger 11).

[0078] According to the above configuration, the pump bypass line 6 is connected downstream of the second heat exchanger 14 in the cold heat recovery cycle 3 and upstream of the cold heat turbine 32. In this case, even if the cold heat pump 31 is driven and the liquid-phase cold heat medium is sent to the downstream side of the cold heat pump 31, since the liquid-phase cold heat medium vaporizes in the second heat exchanger 14, on the downstream side of the second heat exchanger 14, the vapor-phase cold heat medium flows in the same manner as before driving the cold heat pump 31. Therefore, compared with the case where the pump bypass line 6 is connected upstream of the second heat exchanger 14 in the cold heat recovery cycle 3, the inflow of the liquid-phase cold heat medium into the pump bypass line 6 can be suppressed. As a result, the phase of the cold heat medium flowing through the pump bypass line 6 can be stabilized during the period from the start-up to the steady operation of the cold heat recovery system 1, and the volume change of the cold heat medium flowing through the pump bypass line 6 can be suppressed, so that the cold heat recovery system 1 can be gently shifted to the steady operation. Further, according to the above configuration, since the control device (for example, valve) and the measuring device provided in the pump bypass line 6 may be of single-phase specification (vapor-phase specification), the cost of the devices in the cold heat recovery system 1 can be reduced.

[0079] In some embodiments, as shown in FIG. 4, the above-described pump bypass line 6 is connected downstream of the second heat exchanger 14 in the cold heat recovery cycle 3 and upstream of the cold heat turbine 32. The above-described cold heat recovery system 1 further includes a check valve 63 provided in the pump bypass line 6 and configured to allow only the flow from the first gas-liquid separator 5 toward the cold heat recovery cycle 3.

[0080] The check valve 63 is configured to allow the cold heat medium to flow from one side 61 to the other side 62 of the pump bypass line 6, but to close the valve when the cold heat medium attempts to flow from the other side 62 to the one side 61 of the pump bypass line 6.

[0081] According to the above configuration, the check valve 63 can prevent the vapor-phase heat medium for cold heat, which has been heated in the second heat exchanger 14, from flowing backward through the pump bypass line 6 and entering the first gas-liquid separator 5. In this case, it is possible to prevent the cooling of the first gas-liquid separator 5 from being delayed due to the vapor-phase heat medium for cold heat flowing backward through the pump bypass line 6, so that the cold heat recovery system 1 can be quickly shifted to steady operation.

[0082] In some embodiments, as shown in FIGS. 1 and 4, the above-described cold heat recovery cycle 3 includes the above-described second connection line (main line) 34 and the above-described turbine bypass line 37, and the above-described blower 7A is provided in the turbine bypass line 37.

[0083] According to the above configuration, the blowing means 7 provided in the turbine bypass line 37 can send the vapor-phase heat medium for cold heat separated by the first gas-liquid separator 5 to the first heat exchanger 11 via the turbine bypass line 37 (bypassing the cold heat turbine 32). Thereby, the pressure loss in the cold heat turbine 32 can be suppressed, so that the performance of the blowing means 7 can be effectively exerted when the cold heat recovery system 1 is started. Further, according to the above configuration, when the cold heat turbine 32 is driven, the heat medium for cold heat can be sent to the first heat exchanger 11 without passing through the turbine bypass line 37. Thereby, the pressure loss in the blower 7A can be suppressed, so that the performance of the cold heat turbine 32 can be effectively exerted during the steady operation of the cold heat recovery system 1.

[0084] (Second gas-liquid separator) FIG. 5 is a schematic configuration diagram schematically showing the configuration of a ship or a floating body including the cold heat recovery system according to the third embodiment of the present disclosure. In some embodiments, as shown in FIG. 5, the above-described pump bypass line 6 is connected downstream of the second heat exchanger 14 in the cold heat recovery cycle 3 and upstream of the cold heat turbine 32. The above-described cold heat recovery cycle 3 includes the above-described second connection line (main line) 34 and the above-described turbine bypass line 37, and the above-described blower 7A is provided in the turbine bypass line 37. The above-described cold heat recovery system 1 further includes a second gas-liquid separator 8 configured to separate the cold heat transfer medium into a gas phase and a liquid phase. The second gas-liquid separator 8 is provided either between the connection position P5 and the branch portion P2 in the second connection line 34 or upstream of the blowing means 7 in the turbine bypass line 37.

[0085] In the embodiment shown in FIG. 5, the second gas-liquid separator 8 is provided upstream of the branch portion P2 in the second upper connection line 34A. The second gas-liquid separator 8 includes a main body portion 82 configured to define an internal space 81 into which the cold heat transfer medium sent from the pump bypass line 6 and the second heat exchanger 14 is introduced, a first inlet 83 for introducing the cold heat transfer medium from the second heat exchanger 14 into the internal space 81, a second inlet 84 for introducing the cold heat transfer medium from the pump bypass line 6 into the internal space 81, and a gas phase discharge port 85 for discharging the gas-phase cold heat transfer medium from the internal space 81 to the outside of the second gas-liquid separator 8.

[0086] The internal space 81 includes a lower storage space 81B in which the liquid-phase cold heat transfer medium is stored, and an upper storage space 81A provided above the lower storage space 81B and communicating with the lower storage space 81B, in which the gas-phase cold heat transfer medium is stored. Each of the first inlet 83, the second inlet 84, and the gas phase discharge port 85 communicates with the upper storage space 81A.

[0087] The cold heat transfer medium heated by the second heat exchanger 14 is led to the second gas-liquid separator 8 through a portion of the second upper connection line 34A upstream of the second gas-liquid separator 8. The other side (downstream end) 62 of the pump bypass line 6 is connected to the second inlet 84. The gaseous cold heat transfer medium stored in the first gas-liquid separator 5 is led to the second gas-liquid separator 8 through the pump bypass line 6. The gaseous cold heat transfer medium flowing into the internal space 81 from the first inlet 83 and the second inlet 84 has the liquid phase separated in the internal space 81. Downstream of the second gas-liquid separator 8 in the second upper connection line 34A, the gaseous cold heat transfer medium from which the liquid phase has been separated in the second gas-liquid separator 8 flows.

[0088] When starting up the cold heat recovery system 1 (specifically, during the second period T2), when changing the cold heat transfer medium circulating in the cold heat recovery cycle 3 from the gaseous phase to the liquid phase, if the liquid portion of the cold heat transfer medium suddenly flows into the turbine bypass line 37, there is a risk of causing a failure of the blower 7A. According to the above configuration, the second gas-liquid separator 8 separates the cold heat transfer medium into the gaseous phase and the liquid phase, thereby suppressing the liquid portion of the cold heat transfer medium from flowing into the turbine bypass line 37 and causing a failure of the blower 7A, so that the reliability of the cold heat recovery system 1 can be improved.

[0089] Note that the second gas-liquid separator 8 may be configured to discharge the liquid-phase cold heat transfer medium stored in the lower storage space 81B to the outside of the second gas-liquid separator 8. As shown in FIG. 5, the second gas-liquid separator 8 may include a liquid delivery line 86 for sending the liquid-phase cold heat transfer medium stored in the lower storage space 81B to the internal space 51 of the first gas-liquid separator 5. The liquid delivery line 86 includes a flow path connecting the lower storage space 81B and the internal space 51.

[0090] (Specific Example 3 of the Connection Position of the Pump Bypass Line) FIG. 6 is a schematic configuration diagram schematically showing the configuration of a ship or a floating body including a cold heat recovery system according to a fourth embodiment of the present disclosure. In some embodiments, as shown in FIG. 6, the above-described pump bypass line 6 is connected to a downstream side of the cold heat turbine 32 in the cold heat recovery cycle 3. The blower 7B (blowing means 7) is provided in the pump bypass line 6.

[0091] In the embodiment shown in FIG. 6, the other side (downstream end) 62 of the pump bypass line 6 is connected to the connection position P6 of the second lower connection line 34B. As shown in FIG. 6, the turbine bypass line 37 may merge into the pump bypass line 6 at the merging portion P7 and share the line 37A from the merging portion P7 to the connection position P6 with the pump bypass line 6.

[0092] In the illustrated embodiment, the blowing means 7 includes a blower 7B provided upstream of the merging portion P7 of the pump bypass line 6. The blower 7B is configured to send the gaseous cold heat medium to the downstream side of the pump bypass line 6. In the illustrated embodiment, the blower 7B includes a rotating shaft 71, a moving blade 72 attached to the rotating shaft 71, a casing 73 that rotatably houses the moving blade 72, and an electric motor 74 configured to supply a driving force for rotating the moving blade 72 to the moving blade 72, similar to the above-described blower 7A.

[0093] The moving blade 72 is disposed upstream of the merging portion P7 of the pump bypass line 6. The casing 73 is formed with an inlet 731 for introducing the gaseous cold heat medium into the inside of the casing 73 and an outlet 732 for discharging the gaseous cold heat medium that has passed through the moving blade 72 to the outside of the casing 73. The electric motor 74 is mechanically connected to the rotating shaft 71. The moving blade 72 rotates when the driving force generated by the electric motor 74 is transmitted through the rotating shaft 71.

[0094] The pump bypass line 6 includes a first pump bypass line 6A that connects the gas-phase discharge port 55 of the first gas-liquid separator 5 and the inlet 731 of the blower 7B, and a second pump bypass line 6B that connects the discharge port 732 of the blower 7B and the connection position P6 of the second lower-stage connection line 34B.

[0095] In the embodiment shown in FIG. 6, in the above-described blowing step S102, by driving the blower 7B, the gas-phase heat medium for cooling and heating is extracted from the first gas-liquid separator 5 into the pump bypass line 6. The gas-phase heat medium for cooling and heating extracted by the blower 7B passes through the downstream side of the pump bypass line 6 and the connection position P6 of the second lower-stage connection line 34B by the blower 7B, and then is sent to the first cooling and heating side flow path 112 (the first heat exchanger 11). The heat medium for cooling and heating sent to the first cooling and heating side flow path 112 is sent to the first gas-liquid separator 5 after passing through the first upper-stage connection line 33A.

[0096] When changing the heat medium for cooling and heating circulating in the cooling and heating recovery cycle 3 from the gas phase to the liquid phase, etc., the pressure of the gas-phase heat medium for cooling and heating introduced into the blowing means 7 suddenly increases, and the operating point of the blowing means 7 suddenly changes, which may damage the blowing means 7. According to the above configuration, by connecting the pump bypass line 6 to the downstream side of the heat medium turbine 32 for cooling and heating, it is possible to suppress the direct inflow of the heat medium for cooling and heating that has passed through the second heat exchanger 14 into the pump bypass line 6. Thereby, since the sudden change in the operating point of the blower 7B (blowing means 7) provided in the pump bypass line 6 can be suppressed, the risk of damage to the blower 7B can be reduced. In addition, since the pressure resistance performance required for the blower 7B can be reduced, the cost of the blower 7B can be reduced.

[0097] In some embodiments, as shown in FIG. 6, the above-described pump bypass line 6 is connected downstream of the cold and heat turbine 32 in the cold and heat recovery cycle 3. The blower 7B is provided in the pump bypass line 6. The above-described cold and heat recovery system 1 further includes a reflux line 64 that bypasses the blower 7B and connects the downstream side and the upstream side of the blowing means 7 of the pump bypass line 6. One side of the reflux line 64 is connected to the branch portion P8 of the second pump bypass line 6B, and the other side of the reflux line 64 is connected to the confluence portion P9 of the first pump bypass line 6A.

[0098] According to the above configuration, when the blower 7B is stopped, the cold and heat medium may flow backward through the pump bypass line 6. When the cold and heat medium flows backward through the pump bypass line 6, the reflux line 64 can be passed through because the pressure loss of the reflux line 64 is smaller than that of the line provided with the blower 7B. By suppressing the inflow of the backward-flowing cold and heat medium into the blower 7B, the steady operation of the blower 7B can be maintained for a long period of time, so that damage due to surging of the blower 7B can be suppressed. Thereby, the reliability of the cold and heat recovery system 1 can be improved.

[0099] (Pressure reducing valve) In some embodiments, as shown in FIG. 6, a pressure reducing valve 65 provided downstream of the branch portion P8 of the second pump bypass line 6B may be further provided. In the embodiment shown in FIG. 6, the pressure reducing valve 65 is provided upstream of the connection position with the confluence portion P7 in the second pump bypass line 6B. According to the above configuration, the pressure reducing valve 65 can suppress the high-pressure cold and heat medium that has passed through the second heat exchanger 14 from flowing into the upstream side of the pressure reducing valve 65 of the second pump bypass line 6B. Thereby, the sudden change in the operating point of the blower 7B (blowing means 7) can be effectively suppressed, so that the damage risk of the blower 7B can be effectively reduced. In addition, since the pressure resistance performance required for the blower 7B can be reduced, the cost of the blower 7B can be reduced.

[0100] (Specific example 3 of the connection position of the pump bypass line) FIG. 7 is a schematic configuration diagram schematically showing the configuration of a ship or a floating body including the heat recovery system according to the fifth embodiment of the present disclosure. In some embodiments, as shown in FIG. 7, the pump bypass line 6 described above includes a first line 6C connected to a first connection position P10 downstream of the turbine 32 for cold heat in the cold heat recovery cycle 3 from the first gas-liquid separator 5, a second line 6D in the cold heat recovery cycle 3 extending from the first connection position P10 to a branch position P11 upstream of the turbine 32 for cold heat, and a third line 6E connected from the branch position P11, bypassing the turbine 32 for cold heat, to a second connection position P12 downstream of the first connection position P10 in the cold heat recovery cycle 3. The turbine 32 for cold heat provided in the second line 6D is configured to function as the air blowing means 7 by rotating in the reverse direction.

[0101] In the illustrated embodiment, the generator 326 for cold heat is configured to convert the rotational force of the turbine blade 322 into electric power when the turbine blade 322 rotates (rotates forward) on one side in the rotational direction. Further, the generator 326 for cold heat has a function as an inverter motor, and is configured to generate a rotational force that rotates (rotates in the reverse direction) the turbine blade 322 to the other side in the rotational direction (the direction opposite to the above one side) when electric power is supplied.

[0102] In the startup method 100 of the heat recovery system 1 described above, the turbine 32 for cold heat functions as the air blowing means 7 from the start of the air blowing step S102 to the air blowing means stop step S106. By the reverse rotation of the turbine 32 for cold heat, a vapor-phase heat medium for cold heat can be sent to the downstream side of the pump bypass line 6.

[0103] In the illustrated embodiment, one side (upstream end) 61 of the first line 6C is connected to the gas-phase discharge port 55 of the first gas-liquid separator 5, and one side (downstream end) 62 of the third line 6E is connected to the confluence part P3 (second connection position P12) of the second lower connection line 34B. The other side (downstream end) of the first line 6C is connected to the first connection position P10 upstream of the confluence part P3 of the second lower connection line 34B. The second line 6D serves as a shared line for the part downstream of the branch part P2 (P11) of the second upper connection line 34A and the part upstream of the confluence part P3 (P10) of the second lower connection line 34B. The third line 6E and the turbine bypass line 37 serve as a shared line.

[0104] As shown in FIG. 7, the above-described cold and heat recovery system 1 may further include a first on-off valve 91 provided between the confluence part P3 (P10) of the second lower connection line 34B and the second connection position P12, and a second on-off valve 92 provided upstream of the branch part P2 (P11) of the second upper connection line 34A.

[0105] In the above-described air supply step S102, with the first on-off valve 91 and the second on-off valve 92 fully closed, the cold and heat medium in the gas phase extracted from the first gas-liquid separator 5 is sent to the first cold and heat side flow path 112 (first heat exchanger 11) after passing through the downstream side of the confluence part P3 of the first line 6C, the second line 6D, the third line 6E, and the second lower connection line 34B by the reversely rotating cold and heat turbine 32.

[0106] According to the above configuration, by making the cold and heat turbine 32 function as the air supply means 7, a dedicated air supply means for sending the cold and heat medium in the gas phase through the pump bypass line 6 becomes unnecessary, so that the cost of equipment in the cold and heat recovery system 1 can be reduced.

[0107] In some embodiments, as shown in FIGS. 1, 4 to 7, the above-described gas supply destination 22 includes the main engine 22A of the ship 2A or the floating body 2B. The main engine 22A is configured to generate a driving force (propulsive force) that drives a propeller (not shown) or the like by the energy of the supplied vaporized gas. The above-described vaporized gas supply line 13 includes a fuel supply line 13A for supplying the liquefied gas vaporized in the first heat exchanger 11 to the main engine 22A of the ship 2A or the floating body 2B.

[0108] The above-described cold heat recovery system 1 further includes a branch line 24 that branches from the fuel supply line 13A and supplies the liquefied gas (vaporized gas) vaporized in the first heat exchanger 11 to a supply destination different from the main engine 22A, and a gas combustion device 23 configured separately from the main engine 22A and connected to the branch line 24. One side (upstream end) of the branch line 24 is connected to the branch portion 25 of the fuel supply line 13A, and the other side (downstream end) is connected to the gas inlet of the gas combustion device 23. The gas combustion device 23 is configured to burn the supplied gas.

[0109] The above-described cold heat recovery system 1 may further include a third on-off valve 26 provided on the downstream side of the branch portion 25 of the fuel supply line 13A and a fourth on-off valve 27 provided on the branch line 24. When the cold heat recovery system 1 is started, the third on-off valve 26 is fully closed and the fourth on-off valve 27 is open. Therefore, the gas sent from the first heat exchanger 11 is sent to the gas combustion device 23. After executing the blower means stop step S106, when the flow rate of the heat medium for cold heat circulating in the cold heat recovery cycle 3 can be ensured, the fourth on-off valve 27 is fully closed and the third on-off valve 26 is opened. Thereby, the gas sent from the first heat exchanger 11 is sent to the main engine 22A.

[0110] When the cold and heat recovery system 1 is started, since the flow rate of the heat transfer medium for cold and heat circulating in the cold and heat recovery cycle 3 is small, liquefied gas is supplied to the main engine 22A without being sufficiently vaporized, which may cause a failure or malfunction of the main engine 22A. According to the above configuration, when the cold and heat recovery system 1 is started, vaporized gas or liquefied gas can be guided to the gas combustion device 23 through the branch line 24 and burned in the gas combustion device 23. Thereby, since it is possible to suppress the supply of liquefied gas to the main engine 22A without being sufficiently vaporized, it is possible to suppress the failure or malfunction of the main engine 22A.

[0111] (Control device) FIG. 8 is an explanatory diagram for explaining a control device of a cold and heat recovery system according to an embodiment of the present disclosure. In some embodiments, as shown in FIG. 8, the cold and heat recovery system 1 includes a liquid level acquisition device (in the illustrated example, a liquid level sensor) 93 configured to be able to acquire the liquid level WL of the heat transfer medium for cold and heat inside the first gas-liquid separator 5, and a cold and heat pump control device 94 that drives the cold and heat pump 31 when the liquid level WL acquired by the liquid level acquisition device 93 exceeds a threshold value TH. The starting method 100 of the cold and heat recovery system 1 described above further includes a liquid level acquisition step S109 of acquiring the liquid level WL of the liquid-phase heat transfer medium for cold and heat stored inside the first gas-liquid separator 5, and when the liquid level WL acquired in the liquid level acquisition step S109 exceeds the threshold value TH, the cold and heat pump drive step S104 is performed.

[0112] In the illustrated embodiment, the cooling / heating pump control device 94 is mounted on the control device 9 configured to perform operation control of the pumps included in the cooling / heating recovery system 1 and opening degree control of the valves included in the cooling / heating recovery system 1. The pumps (such as the cooling / heating pump 31) included in the cooling / heating recovery system 1 are configured to be driven and stopped in response to the operation instructions of the control device 9. The valves (such as the first flow rate adjustment valve 36) included in the cooling / heating recovery system 1 are configured to be able to adjust their opening degrees in response to the opening degree instructions of the control device 9. The cooling / heating recovery system 1 includes the control device 9. Note that some steps in the startup method 100 may be performed by the control device 9. Also, some steps in the startup method 100 may be performed using devices and equipment other than the control device 9, or may be performed manually.

[0113] The control device 9 is an electronic control unit for controlling the cooling / heating recovery system 1. The control device 9 is configured as a microcomputer including a CPU (processor) not shown, a memory such as a ROM and a RAM, a storage device such as an external storage device, an I / O interface, a communication interface, and the like. The control device 9 may realize the control in the cooling / heating pump control device 94 by the CPU operating (such as performing data operations) according to the instructions of a program loaded into the main storage device of the memory, for example.

[0114] According to the above configuration and method, when the liquid level WL of the liquid-phase cooling / heating heat medium stored inside the first gas-liquid separator 5 exceeds the threshold value TH, the ratio occupied by the liquid-phase cooling / heating heat medium in the cooling / heating pump 31 is sufficiently large. By using the liquid level WL as a determination criterion, it is possible to effectively suppress the reduction in capacity due to gas biting of the cooling / heating pump 31.

[0115] The present disclosure is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments and forms obtained by appropriately combining these forms.

[0116] The content described in some of the above-described embodiments is understood as follows, for example.

[0117] 1) The heat recovery system (1) according to at least one embodiment of the present disclosure 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, a first heat exchanger (11) configured to transfer cold heat energy from the liquefied gas withdrawn from the liquefied gas storage device (21) to a heat medium for cold heat, a cold heat recovery cycle (3) configured to circulate the heat medium for cold heat, the cold heat recovery cycle (3) including at least a cold heat pump (31) for sending the heat medium for cold heat provided downstream of the first heat exchanger (21), a first gas-liquid separator (5) provided between the first heat exchanger (11) and the cold heat pump (31) in the cold heat recovery cycle (3) and configured to separate the heat medium for cold heat into a gaseous heat medium for cold heat and a liquid heat medium for cold heat, a pump bypass line (6) for extracting the gaseous heat medium for cold heat from the first gas-liquid separator (5) and guiding it to a downstream side of the cold heat pump (31) and an upstream side of the first heat exchanger (11) in the cold heat recovery cycle (3), and a blowing means (7) for sending the gaseous heat medium for cold heat to the first heat exchanger (11) via the pump bypass line (6).

[0118] According to the configuration of 1) above, the blowing means (7) sends the gaseous heat medium for cold heat separated by the first gas-liquid separator (5) to the first heat exchanger (11) via the pump bypass line (6), so that the gaseous heat medium for cold heat can be circulated in the cold heat recovery cycle (3). Since the gaseous heat medium for cold heat is less likely to cause blockage in the first heat exchanger (11) compared to the liquid heat medium for cold heat, blockage of the first heat exchanger (11) at the start-up of the heat recovery system (1) can be suppressed.

[0119] Further, according to the configuration of 1) above, when the cold and heat recovery system (1) is started, the gaseous heat medium for cold and heat that circulates in the cold and heat recovery cycle (3) is cooled and condensed by liquefied gas in the first heat exchanger (11). Thus, the proportion of the liquid-phase heat medium for cold and heat can be increased earlier on the downstream side of the first heat exchanger (11) in the cold and heat recovery cycle (3), such as in the gas-liquid separator and the pump for cold and heat. By increasing the proportion of the liquid-phase heat medium for cold and heat in the pump for cold and heat, the reduction in capacity due to gas biting of the pump for cold and heat (31) can be suppressed, so that the capacity of the pump for cold and heat (31) can be exerted from the early stage. As a result, the cold and heat recovery system can be shifted to steady operation earlier.

[0120] 2) In some embodiments, there is provided the cold and heat recovery system (1) described in 1) above, wherein the cold and heat recovery cycle (3) further includes a cold and heat turbine (32) configured to be driven by the heat medium for cold and heat provided upstream of the first heat exchanger (11). The cold and heat recovery system (1) further includes a second heat exchanger (14) configured to transfer thermal energy from the heat medium to the heat medium for cold and heat flowing downstream of the pump for cold and heat (31) and upstream of the cold and heat turbine (32) in the cold and heat recovery cycle (3). The pump bypass line (6) is connected upstream of the second heat exchanger (14) in the cold and heat recovery cycle (3).

[0121] According to the configuration of 2) above, the pump bypass line (6) is connected upstream of the second heat exchanger (14) in the cold and heat recovery cycle (3). In this case, even if the cold and heat pump (31) is driven and the liquid-phase cold and heat heat medium is fed downstream of the cold and heat pump (31), since the liquid-phase cold and heat heat medium vaporizes in the second heat exchanger (14), on the downstream side of the second heat exchanger (14), the vapor-phase cold and heat heat medium flows in the same manner as before driving the cold and heat pump (31). Therefore, during the period from the startup to the steady operation of the cold and heat recovery system (1), the transient change of the cold and heat heat medium flowing on the downstream side of the second heat exchanger (14) and upstream of the first heat exchanger (11) can be suppressed. Also, even after driving the cold and heat pump (31), since the vapor-phase cold and heat heat medium flows on the downstream side of the second heat exchanger (14) and upstream of the first heat exchanger (11), there is no need to suddenly stop the blowing means (7), and it is possible to gently shift the cold and heat recovery cycle (3) to steady operation. Thus, according to the configuration of 2) above, the reliability during the period from the startup to the steady operation of the cold and heat recovery system (1) can be improved.

[0122] 3) In some embodiments, the cold and heat recovery system (1) described in 1) above, the cold and heat recovery cycle (3) further includes a cold and heat turbine (32) configured to be driven by the cold and heat heat medium provided upstream of the first heat exchanger (11), the cold and heat recovery system (1) further includes a second heat exchanger (14) configured to transfer heat energy from the heat medium to the cold and heat heat medium flowing downstream of the cold and heat pump (31) and upstream of the cold and heat turbine (32) in the cold and heat recovery cycle (3), the pump bypass line (6) is connected downstream of the second heat exchanger (14) and upstream of the cold and heat turbine (32) in the cold and heat recovery cycle (3).

[0123] According to the configuration of 3) above, the pump bypass line (6) is connected downstream of the second heat exchanger (14) in the cold and heat recovery cycle (3) and upstream of the cold and heat turbine (32). In this case, even if the cold and heat pump (31) is driven and a liquid-phase cold and heat heat medium is sent to the downstream side of the cold and heat pump (31), since the liquid-phase cold and heat heat medium vaporizes in the second heat exchanger (14), on the downstream side of the second heat exchanger (14), the gas-phase cold and heat heat medium flows in the same manner as before driving the cold and heat pump (31). Therefore, compared with the case where the pump bypass line (6) is connected upstream of the second heat exchanger (14) in the cold and heat recovery cycle (3), the inflow of the liquid-phase cold and heat heat medium into the pump bypass line (6) can be suppressed. As a result, the phase of the cold and heat heat medium flowing through the pump bypass line (6) can be stabilized during the period from the start-up of the cold and heat recovery system (1) to the steady operation, and the volume change of the cold and heat heat medium flowing through the pump bypass line (6) can be suppressed, so that the cold and heat recovery system (1) can be gently shifted to the steady operation. Further, according to the configuration of 3) above, the control device (for example, a valve) and the measuring device provided in the pump bypass line (6) may be of single-phase specification (gas-phase specification), so that the cost of the devices in the cold and heat recovery system (1) can be reduced.

[0124] 4) In some embodiments, it is the cold and heat recovery system (1) described in 3) above, further comprising a check valve (63) provided in the pump bypass line (6) and configured to allow only the flow from the first gas-liquid separator (5) to the cold and heat recovery cycle (3).

[0125] According to the configuration of 4) above, the check valve (63) can suppress the gas-phase cold and heat heat medium heated up in the second heat exchanger (14) from flowing backward through the pump bypass line (6) and flowing into the first gas-liquid separator (5). In this case, it is possible to suppress the delay in the cooling of the first gas-liquid separator (5) due to the gas-phase cold and heat heat medium flowing backward through the pump bypass line (6), so that the cold and heat recovery system (1) can be quickly shifted to the steady operation.

[0126] 5) In some embodiments, there is provided the cold and heat recovery system (1) described in 2) above, wherein the cold and heat recovery cycle (3) includes a main line (second connection line 34) connecting the second heat exchanger (14) and the first heat exchanger (11) and provided with the cold and heat turbine (32) between the second heat exchanger (14) and the first heat exchanger (11), and a turbine bypass line (37) connecting the upstream side and the downstream side of the cold and heat turbine (32) in the main line (34) by bypassing the cold and heat turbine (32). The air blowing means (7) is provided in the turbine bypass line (37).

[0127] According to the configuration of 5) above, the air blowing means (7) provided in the turbine bypass line (37) can send the gas-phase cold and heat heat medium separated by the first gas-liquid separator (5) to the first heat exchanger (11) via the turbine bypass line (37). Thereby, the pressure loss in the cold and heat turbine 32 can be suppressed, so that the performance of the air blowing means (7) can be effectively exerted when the cold and heat recovery system (1) is started.

[0128] 6) In some embodiments, there is provided the cold and heat recovery system (1) described in 3) or 4) above, wherein the cold and heat recovery cycle (3) includes a main line (second connection line 34) connecting the second heat exchanger (14) and the first heat exchanger (11) and provided with the cold and heat turbine (32) between the second heat exchanger (14) and the first heat exchanger (11), and a turbine bypass line (37) connecting the upstream side and the downstream side of the cold and heat turbine (32) in the main line (34) by bypassing the cold and heat turbine (32). The air blowing means (7) is provided in the turbine bypass line (37).

[0129] According to the configuration of 6) above, the gas-phase heat medium for cold heat separated by the first gas-liquid separator (5) can be sent to the first heat exchanger (11) via the turbine bypass line (37) by the blowing means (7) provided in the turbine bypass line (37). Thereby, since the pressure loss in the cold heat turbine (32) can be suppressed, the performance of the blowing means (7) can be effectively exhibited when the cold heat recovery system (1) is started up.

[0130] 7) In some embodiments, it is the cold heat recovery system (1) described in 6) above, A second gas-liquid separator (8) is provided at any one of the connection position of the pump bypass line (6) in the main line (34) from the connection position (P5) to the connection position (branch portion P2) of the upstream end of the turbine bypass line (37), or upstream of the blowing means (7) of the turbine bypass line (37), and is configured to separate the heat medium for cold heat into a gas-phase heat medium for cold heat and a liquid-phase heat medium for cold heat.

[0131] When changing the heat medium for cold heat circulating in the cold heat recovery cycle (3) from the gas phase to the liquid phase, etc., if the liquid portion of the heat medium for cold heat suddenly flows into the turbine bypass line (37), there is a risk of causing a failure of the blowing means (7). According to the configuration of 7) above, the second gas-liquid separator (8) separates the heat medium for cold heat into a gas phase and a liquid phase, thereby suppressing the liquid portion of the heat medium for cold heat from flowing into the turbine bypass line (37) and causing a failure of the blowing means (7), so that the reliability of the cold heat recovery system (1) can be improved.

[0132] 8) In some embodiments, it is the cold heat recovery system (1) described in 1) above, The cold heat recovery cycle (3) further includes a cold heat turbine (32) configured to be driven by the heat medium for cold heat provided upstream of the first heat exchanger (11), The pump bypass line (6) is connected downstream of the cold heat turbine (32) in the cold heat recovery cycle (3), The air blowing means (7) is provided in the pump bypass line (6).

[0133] When changing the heat transfer medium for cooling and heating that circulates in the cooling and heating recovery cycle 3 from the gas phase to the liquid phase, etc., the pressure of the gas-phase heat transfer medium for cooling and heating introduced into the air blowing means (7) suddenly increases, and due to the sudden change in the operating point of the air blowing means (7), the air blowing means (7) may be damaged. According to the configuration of the above (8), by connecting the pump bypass line (6) to the downstream side of the turbine (32) for cooling and heating, it is possible to suppress the direct inflow of the heat transfer medium for cooling and heating that has passed through the second heat exchanger (14) into the pump bypass line (6). Thereby, a sudden change in the operating point of the air blowing means (7) provided in the pump bypass line (6) can be suppressed, so that the risk of damage to the air blowing means (7) can be reduced. In addition, since the pressure resistance performance required for the air blowing means (7) can be reduced, cost reduction of the air blowing means (7) can be achieved.

[0134] 9) In some embodiments, it is the cooling and heating recovery system (1) described in the above (8), It further includes a reflux line (64) that connects the downstream side and the upstream side of the air blowing means (7) of the pump bypass line (6) by bypassing the air blowing means (7).

[0135] According to the configuration of the above (9), when the heat transfer medium for cooling and heating flows backward through the pump bypass line (6), since the reflux line (64) has a smaller pressure loss than the line provided with the air blowing means (7), it is possible to make it pass through the reflux line (64). By suppressing the inflow of the heat transfer medium for cooling and heating flowing backward into the air blowing means (7), the steady operation of the air blowing means (7) can be maintained for a long period of time, so that damage due to surging of the air blowing means (7) can be suppressed. Thereby, the reliability of the cooling and heating recovery system (1) can be improved.

[0136] 10) In some embodiments, it is the cooling and heating recovery system (1) described in the above (1), The cooling and heating recovery cycle (3) further includes a turbine (32) for cooling and heating driven by the heat transfer medium for cooling and heating provided upstream of the first heat exchanger (11). The pump bypass line (6) is a first line (6C) connected to a first connection position (P10) downstream of the cold heat turbine (32) in the cold heat recovery cycle (3) from the first gas-liquid separator (5); in the cold heat recovery cycle (3), a second line (6D) reaching from the first connection position (P10) to a branch position (P11) upstream of the cold heat turbine (32); a third line (6E) connected from the branch position (P11), bypassing the cold heat turbine (3), to a second connection position (P12) downstream of the first connection position (P10) in the cold heat recovery cycle (3), and includes the cold heat turbine (32) is configured to function as the blowing means (7) by rotating reversely.

[0137] According to the configuration of 10) above, by making the cold heat turbine (32) function as the blowing means (7), a dedicated blowing means for sending the gaseous cold heat medium through the pump bypass line (6) becomes unnecessary, so that the cost of the equipment in the cold heat recovery system 1 can be reduced.

[0138] 11) In some embodiments, it is the cold heat recovery system (1) described in any one of 1) to 10) above, a fuel supply line (13A) for supplying the liquefied gas vaporized by the first heat exchanger (11) to the main engine (22A) of the ship (2A) or the floating body (2B); a branch line (24) branched from the fuel supply line (13A) for supplying the liquefied gas vaporized by the first heat exchanger (11) to a supply destination (23) different from the main engine (22A); and further includes a gas combustion device (23) configured separately from the main engine (22A) connected to the branch line (24).

[0139] When the cold and heat recovery system (1) is started, since the flow rate of the heat medium for cold and heat in the cold and heat recovery cycle (3) is small, the liquefied gas is supplied to the main engine (22A) without being sufficiently vaporized, which may cause a failure or malfunction of the main engine (22A). According to the configuration of the above (11), when the cold and heat recovery system (1) is started, the vaporized gas or liquefied gas can be guided to the gas combustion device (23) through the branch line (24) and burned in the gas combustion device (23). Thereby, since it is possible to suppress the supply of the liquefied gas to the main engine (22A) without being sufficiently vaporized, it is possible to suppress a failure or malfunction of the main engine (22A).

[0140] 12) The starting method (100) of the cold and heat recovery system (1) according to at least one embodiment of the present disclosure is as follows: A starting method (100) of a cold and 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, wherein the cold and heat recovery system (1) includes: a first heat exchanger (11) configured to transfer cold and heat energy from the liquefied gas withdrawn from the liquefied gas storage device (21) to a heat medium for cold and heat; a cold and heat recovery cycle (3) configured to circulate the heat medium for cold and heat, the cold and heat recovery cycle (3) including a cold and heat pump (31) for sending the heat medium for cold and heat provided downstream of the first heat exchanger (11); The starting method (100) of the cold and heat recovery system includes: a gas-liquid separation step (S101) of separating the heat medium for cold and heat into a gaseous heat medium for cold and heat and a liquid heat medium for cold and heat by a gas-liquid separator (5) provided between the first heat exchanger (11) and the cold and heat pump (31) in the cold and heat recovery cycle (3); a blowing step (S102) of sending the gaseous heat medium for cold and heat separated in the gas-liquid separation step (S101) to the first heat exchanger (11) bypassing the cold and heat pump (31); Send the liquefied gas from the liquefied gas storage device (21) to the first heat exchanger (11), and a cooling step (S103) of cooling the gaseous heat medium for cold heat sent to the first heat exchanger (11) in the air supply step (S102) with the liquefied gas. A cold heat pump driving step (S104) of driving the cold heat pump (31) after the cooling step (S103).

[0141] According to the method of 12) above, the gaseous heat medium for cold heat separated in the gas-liquid separation step (S101) is sent to the first heat exchanger (11) by bypassing the cold heat pump (31) (air supply step S102), so that the gaseous heat medium for cold heat can be circulated in the cold heat recovery cycle (3). Since the gaseous heat medium for cold heat is less likely to cause blockage in the first heat exchanger (11) than the liquid heat medium for cold heat, blockage of the first heat exchanger (11) at the start of the cold heat recovery system (1) can be suppressed.

[0142] Also, according to the method of 12) above, the gaseous heat medium for cold heat circulating in the cold heat recovery cycle (3) is cooled (cooling step S103) and condensed by the liquefied gas in the first heat exchanger (11), so that the proportion of the liquid heat medium for cold heat can be increased earlier on the downstream side of the first heat exchanger (11) in the cold heat recovery cycle (3) such as the gas-liquid separator (5) and the cold heat pump (31). By increasing the proportion of the liquid heat medium for cold heat in the cold heat pump (31), the reduction in capacity due to gas biting of the cold heat pump (31) can be suppressed, so that the cold heat pump (31) can be driven earlier (cold heat pump driving step S104), and the capacity of the cold heat pump (31) can be exerted from the early stage. Thereby, the cold heat recovery cycle (1) can be shifted to steady operation earlier.

[0143] 13) In some embodiments, it is a start-up method (100) of the cold heat recovery system (1) described in 12) above, Further comprising a liquid level acquisition step (S109) of acquiring the liquid level of the liquid heat medium for cold heat stored inside the gas-liquid separator (5). When the liquid level acquired in the liquid level acquisition step (S109) exceeds a threshold value, the cold and heat pump driving step (S104) is performed.

[0144] According to the method of the above 13), when the liquid level of the liquid-phase cold and heat heat medium stored inside the first gas-liquid separator (5) exceeds the threshold value, the ratio of the liquid-phase cold and heat heat medium in the cold and heat pump (31) is sufficiently large. By using the above liquid level as a determination criterion, the reduction in the capacity of the cold and heat pump (31) due to gas biting can be effectively suppressed.

Explanation of symbols

[0145] 1 Cold and heat recovery system 2A Ship 2B Floating body 3 Cold and heat recovery cycle 5 First gas-liquid separator 6 Pump bypass line 6A First pump bypass line 6B Second pump bypass line 6C First line 6D Second line 6E Third line 7 Blowing means 7A, 7B Blower 8 Second gas-liquid separator 9 Control device 11 First heat exchanger 12 Liquefied gas supply line 13 Vaporized gas supply line 14 Second heat exchanger 15 Liquefied gas pump 21 Liquefied gas storage device 22 Gas supply destination 22A Main engine 23 Gas combustion device 24 Branch line 26 Third on-off valve 27 Fourth on-off valve 31 Cold and heat pump 32 Cold and heat turbine 33 First connection line 33A First upper connection line 33B First middle connection line 33C First lower connection line 34 Second connection line 34A Second upper connection line 34B Second lower connection line 35 Liquid return line 36 First flow control valve 37 Turbine bypass line 38 Second flow control valve 39 Third flow control valve 41 Source of external water 42 External water supply line 43 Destination of external water discharge 44 External water discharge line 45 External water pump 51 Internal space 51A Upper storage space 51B Lower storage space 52 Main body part 53 Inlet 54 Liquid phase discharge port 55 Gas phase discharge port 56 Liquid return port 63 Check valve 64 Flow line 65 Pressure reducing valve 71 Rotating shaft 72 Moving blade 73 Casing 74 Electric motor 100 Starting method of heat and cold recovery system S101 Gas-liquid separation step S102 Blowing step S103 Cooling step S104 Heat and cold pump driving step S105 Valve opening step S106 Blowing means stop step S107 Heat and cold turbine driving step S108 External water pump driving step S109 Liquid level acquisition step T1 First period T2 Period 2 T3 Period 3 TH Threshold WL Liquid Level

Claims

1. A cold heat recovery system installed on a ship or a floating body having a liquefied gas storage device configured to store liquefied gas, a first heat exchanger configured to transfer cold heat energy from the liquefied gas withdrawn from the liquefied gas storage device to a heat medium for cold heat; a cold heat recovery cycle configured to circulate the heat medium for cold heat, the cold heat recovery cycle including at least a cold heat pump for sending the heat medium for cold heat provided downstream of the first heat exchanger; a first gas-liquid separator provided between the first heat exchanger and the cold heat pump in the cold heat recovery cycle and configured to separate the heat medium for cold heat into a gaseous heat medium for cold heat and a liquid-phase heat medium for cold heat; a pump bypass line for extracting the gaseous heat medium for cold heat from the first gas-liquid separator and guiding it to a downstream side of the cold heat pump and an upstream side of the first heat exchanger in the cold heat recovery cycle; and a blowing means for sending the gaseous heat medium for cold heat to the first heat exchanger via the pump bypass line. A cold heat recovery system.

2. The cold heat recovery cycle further includes a cold heat turbine configured to be driven by the heat medium for cold heat provided upstream of the first heat exchanger, the cold heat recovery system further includes a second heat exchanger configured to transfer heat energy from a heat medium to the heat medium for cold heat flowing downstream of the cold heat pump and upstream of the cold heat turbine in the cold heat recovery cycle, the pump bypass line is connected upstream of the second heat exchanger in the cold heat recovery cycle, The cold heat recovery system according to claim 1.

3. The cold heat recovery cycle further includes a cold heat turbine configured to be driven by the heat medium for cold heat provided upstream of the first heat exchanger, the cold heat recovery system further includes a second heat exchanger configured to transfer heat energy from a heat medium to the heat medium for cold heat flowing downstream of the cold heat pump and upstream of the cold heat turbine in the cold heat recovery cycle, the pump bypass line is connected downstream of the second heat exchanger and upstream of the cold heat turbine in the cold heat recovery cycle, The cold heat recovery system according to claim 1.

4. Further comprising a check valve provided in the pump bypass line and configured to allow only the flow from the first gas-liquid separator to the cold heat recovery cycle. The cold heat recovery system according to claim 3.

5. The cold heat recovery cycle A main line connecting the second heat exchanger and the first heat exchanger, and provided with the cold heat turbine between the second heat exchanger and the first heat exchanger, A turbine bypass line connecting the upstream side and the downstream side of the cold heat turbine in the main line by bypassing the cold heat turbine, The blowing means is provided in the turbine bypass line, The cold heat recovery system according to claim 2.

6. The cold heat recovery cycle A main line connecting the second heat exchanger and the first heat exchanger, and provided with the cold heat turbine between the second heat exchanger and the first heat exchanger, A turbine bypass line connecting the upstream side and the downstream side of the cold heat turbine in the main line by bypassing the cold heat turbine, The blowing means is provided in the turbine bypass line, The cold heat recovery system according to claim 3 or 4.

7. Further comprising a second gas-liquid separator provided in any one of the pump bypass line, between the connection position of the pump bypass line in the main line to the connection position of the upstream end of the turbine bypass line, or upstream of the blowing means in the turbine bypass line, and configured to separate the cold heat medium into a gaseous cold heat medium and a liquid cold heat medium. The cold heat recovery system according to claim 6.

8. The cold heat recovery cycle further includes a cold heat turbine configured to be driven by the cold heat medium provided upstream of the first heat exchanger. The pump bypass line is connected downstream of the cold heat turbine in the cold heat recovery cycle. The blowing means is provided in the pump bypass line. The cold heat recovery system according to claim 1.

9. Further comprising a reflux line connecting the downstream side and the upstream side of the blowing means in the pump bypass line by bypassing the blowing means. The cold heat recovery system according to claim 8.

10. The cold heat recovery cycle further includes a cold heat turbine driven by the cold heat medium provided upstream of the first heat exchanger. The pump bypass line includes a first line connected to a first connection position downstream of the turbine for cold heat in the cold heat recovery cycle from the first gas-liquid separator, a second line in the cold heat recovery cycle from the first connection position to a branch position upstream of the turbine for cold heat, and a third line from the branch position, bypassing the turbine for cold heat, and connected to a second connection position downstream of the first connection position in the cold heat recovery cycle. The turbine for cold heat is configured to function as the blowing means by rotating in the reverse direction. The cold heat recovery system according to claim 1.

11. A fuel supply line for supplying the liquefied gas vaporized in the first heat exchanger to the main engine of the ship or the floating body, a branch line branched from the fuel supply line for supplying the liquefied gas vaporized in the first heat exchanger to a supply destination different from the main engine, and a gas combustion device configured separately from the main engine and connected to the branch line. The cold heat recovery system according to any one of claims 1 to 10.

12. A method for starting a cold heat recovery system installed on a ship or a floating body having a liquefied gas storage device configured to store liquefied gas, wherein the cold heat recovery system includes a first heat exchanger configured to transfer cold heat energy from the liquefied gas withdrawn from the liquefied gas storage device to a heat medium for cold heat, and a cold heat recovery cycle configured to circulate the heat medium for cold heat, the cold heat recovery cycle including a pump for cold heat for sending the heat medium for cold heat provided downstream of the first heat exchanger. The method for starting the cold heat recovery system includes a gas-liquid separation step of separating the heat medium for cold heat into a gaseous heat medium for cold heat and a liquid-phase heat medium for cold heat by a gas-liquid separator provided between the first heat exchanger and the pump for cold heat in the cold heat recovery cycle, a blowing step of sending the gaseous heat medium for cold heat separated in the gas-liquid separation step to the first heat exchanger by bypassing the pump for cold heat, and a cooling step of sending the liquefied gas from the liquefied gas storage device to the first heat exchanger and cooling the gaseous heat medium for cold heat sent to the first heat exchanger in the blowing step with the liquefied gas. A cold heat pump driving step of driving the cold heat pump after the cooling step, and the method for starting a cold heat recovery system comprising the same. A method for starting a cold heat recovery system.

13. Further comprising a liquid level acquisition step of acquiring a liquid level of the liquid-phase cold heat transfer medium stored inside the gas-liquid separator, The cold heat pump driving step is performed when the liquid level acquired in the liquid level acquisition step exceeds a threshold value. The method for starting a cold heat recovery system according to claim 12.

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