JP2020186691A - Heat recovery device and method for collecting working medium of heat recovery device - Google Patents

Abstract

To provide a technique for reducing labor after a heat recovery device is stopped.SOLUTION: A heat recovery device 100 includes: a circulation flow passage configured to return a working medium sent out by a medium pump 111 to the medium pump 111 after causing the working medium to pass through an evaporator 112, an expander 113, a condenser 114 and a receiver 115 in this order; a cooling pump 117 supplying cooling fluid for condensing the working medium by exchanging heat with the working medium to the condenser 114; an upstream valve 122 opening/closing the circulation flow passage between the receiver 115 and the condenser 114; a downstream valve 121 opening/closing the circulation flow passage between the receiver 115 and the medium pump 111; and a stop control section 123 controlling a stop operation of the heat recovery device 100. The stop control section 123 stops the medium pump 111, closes the downstream valve 121, and when a preset condition is satisfied after the downstream valve 121 is closed, closes the upstream valve 122.SELECTED DRAWING: Figure 1

Description

The present invention relates to a heat recovery device that recovers heat from a heat source using a working medium and a method for collecting the working medium.

A heat recovery device that recovers heat from a heat source using a working medium is known (see Patent Document 1). The heat recovery device includes a medium pump that discharges the working medium, a circulation flow path connected to the discharge port and the suction port of the medium pump, and an evaporator, an expander, a condenser, and a receiver arranged in the circulation flow path. Have. The working medium delivered from the medium pump sequentially passes through the evaporator, the expander, the condenser and the receiver, and returns to the medium pump. The working medium vaporizes under heat exchange with a heat source in the evaporator. The vaporized working medium expands in the expander and performs a predetermined job. The working medium that has finished its work in the inflator is condensed by the condenser, and the condensed working medium flows into the receiver. The working medium stored in the receiver is pumped back to the evaporator by the medium pump.

When the heat recovery device is stopped, the working medium needs to be collected and managed in a predetermined place in order to suppress leakage of the working medium from the heat recovery device. Patent Document 1 proposes to attach a recovery cylinder to a stopped heat recovery device and recover the working medium in the heat recovery device to the recovery cylinder. In this case, the recovery cylinders are collected in a predetermined place after the working medium is collected and properly managed.

JP-A-2019-7373

When a recovery cylinder is used, it is necessary to remove the working medium from the heat recovery device to the recovery cylinder. After the work of extracting the working medium, inspection of the heat recovery device and proper management of the recovery cylinder are required. That is, various operations are required after the heat recovery device is stopped, and the labor involved in these operations is enormous.

An object of the present invention is to provide a technique for reducing labor after the heat recovery device is stopped.

The heat recovery device according to one aspect of the present invention is configured to recover the heat of the heat source. The heat recovery device includes a circulation flow path configured to pass the working medium delivered by the medium pump in the order of an evaporator, an expander, a condenser, and a receiver and then returned to the medium pump, and the working medium. A cooling pump that supplies a cooling fluid that condenses the working medium under heat exchange to the condenser, an upstream valve that opens and closes the circulation flow path between the receiver and the condenser, and the receiver. A downstream valve for opening and closing the circulation flow path and a stop control unit for controlling the stop operation of the heat recovery device are provided between the medium pump and the medium pump. The cooling pump continues to supply the cooling fluid to the condenser even after the start of the stop operation. The stop control unit stops the medium pump and closes the downstream valve, and after the downstream valve is closed, closes the upstream valve when a preset condition is satisfied.

According to the above configuration, the working medium is collected in the receiver, so no recovery cylinder is required. Therefore, labor such as extraction of the working medium from the heat recovery device to the recovery cylinder and management work for managing the recovery cylinder is not required.

With respect to the above configuration, at least a portion of the evaporator may overlap the accommodation space in which the working medium is stored in the receiver.

According to the above configuration, the downstream valve closes so that the working medium in the receiver flows into the evaporator even if at least part of the evaporator overlaps the accommodation space in which the working medium is stored. Is prevented.

With respect to the above configuration, the preset condition is that the saturation temperature of the working medium in the flow path through which the working medium flows toward the condenser is lowered to the temperature of the cooling fluid, or the working medium. The pressure may be reduced to the saturated vapor pressure of the working medium when the temperature of the working medium is the same as the temperature of the cooling fluid.

According to the above configuration, since the upstream valve is closed, the working medium stored in the receiver is not opened to the circulation flow path of the heat recovery device for an unnecessarily long period of time.

In the preset conditions, the temperature of the working medium in the flow path through which the working medium flows toward the condenser is substantially the same as the temperature around the heat recovery device, and the temperature in the flow path is substantially the same. The degree of superheat of the working medium may be 0 ° C. or higher.

According to the above configuration, since the upstream valve is closed, the working medium stored in the receiver is not opened to the circulation flow path of the heat recovery device for an unnecessarily long period of time.

The preset condition may be that the liquid level in the working medium in the receiver reaches a predetermined threshold.

According to the above configuration, the timing at which the upstream valve closes is determined based on the amount of working medium stored in the receiver, so that the upstream valve closes when a sufficient amount of working medium is collected in the receiver. The closing timing of the upstream valve can be set so as to be.

In the collection method according to another aspect of the present invention, the working medium delivered by the medium pump is circulated so as to be returned to the medium pump after passing through the evaporator, the expander, the condenser and the receiver in this order. It is used for collecting the working medium in the heat recovery device that recovers the heat supplied to the evaporator to the working medium. The collection method is to stop the medium pump, stop the outflow of the working medium from the receiver to the medium pump, and continue to supply the cooling fluid to the condenser even after the medium pump is stopped. By doing so, the condensation of the working medium in the condenser is continued, and after the outflow of the working medium from the receiver is stopped, when the preset conditions are satisfied, the condensation is performed. It comprises stopping the outflow of the condensed working medium from the pump to the receiver.

With respect to the above configuration, the preset condition is that the saturation temperature of the working medium in the flow path through which the working medium flows toward the condenser is lowered to the temperature of the cooling fluid, or the working medium. The pressure of the working medium may be reduced to the saturated vapor pressure of the working medium when the temperature of the working medium is the same as the temperature of the cooling fluid.

With respect to the above configuration, the preset conditions are such that the temperature of the working medium in the flow path through which the working medium flows toward the condenser is substantially the same as the temperature around the heat recovery device. The degree of superheat of the working medium in the flow path may be 0 ° C. or higher.

With respect to the above configuration, the preset condition may be that the liquid level in the working medium in the receiver has reached a predetermined threshold.

The above-mentioned technique can reduce the labor after the heat recovery device is stopped.

It is the schematic of the heat recovery apparatus configured to recover heat from a heat source. It is a schematic flowchart which shows the control process of the stop control part of a heat recovery device. It is a schematic diagram of a heat recovery device. It is a schematic diagram of a heat recovery device.

FIG. 1 is a schematic view of a heat recovery device (binary power generation device) 100 configured to recover heat from a heat source (for example, hot air, hot gas, steam or hot water). The heat recovery device 100 will be described with reference to FIG.

The heat recovery device 100 includes a circulation flow path 110 through which the working medium flows, and a medium pump 111, an evaporator 112, an expander 113, a condenser 114, and a receiver 115 arranged on the circulation flow path 110. The heat recovery device 100 further includes a cooling pump 117 that supplies a working medium and a cooling fluid (for example, seawater) having a temperature lower than the ambient temperature of the heat recovery device 100 to the condenser 114. The medium pump 111 has a suction port and a discharge port to which the circulation flow path 110 is connected. The medium pump 111 is fixed at a position lower than the arrangement positions of the evaporator 112, the expander 113, the condenser 114, and the receiver 115. The evaporator 112, the expander 113, the condenser 114, and the receiver 115 are arranged so that the working medium discharged by the medium pump 111 passes through them in sequence.

A heat source having a temperature higher than that of the working medium continuously or intermittently flows into the evaporator 112. The evaporator 112 is configured to evaporate the working medium of the liquid phase discharged by the medium pump 111 under heat exchange with a heat source. The heat exchange section in which the heat exchange takes place between the heat source and the working medium in the evaporator 112 extends in a substantially vertical direction.

The expander 113 has an internal rotor (not shown) that is rotated by the expansion action of the working medium vaporized by the evaporator 112. The internal rotor is connected to the generator 116. The generator 116 generates electric power under the rotation of the internal rotor.

The condenser 114 is configured to heat-exchange the working medium worked in the expander 113 with the cooling fluid supplied by the cooling pump 117 to produce a liquid phase working medium.

The receiver 115 forms a storage space in which the working medium of the liquid phase flowing out of the condenser 114 is stored. At the height position of the receiver 115, at least a part of the accommodation space of the receiver 115 is viewed horizontally, and heat exchange section (that is, heat exchange between the working medium and the heat source is performed in the evaporator 112). It is set to overlap with the section). Therefore, the height position of the liquid level of the working medium formed in the accommodation space of the receiver 115 overlaps the heat exchange section in the evaporator 112 when viewed in the horizontal direction.

The heat recovery device 100 further has a control-related portion used for controlling the stop operation of the heat recovery device 100. The control-related parts include a downstream valve 121, an upstream valve 122, a stop control unit 123, a pressure detection unit 124 (pressure gauge), two temperature detection units 125 and 126 (thermometer), and a bypass flow path 127. Includes an on-off valve 128.

The downstream valve 121 is attached to the circulation flow path 110 on the downstream side of the receiver 115 and on the upstream side of the medium pump 111. The downstream valve 121 is electrically connected to the stop control unit 123. The downstream valve 121 is configured to open and close the flow path of the working medium flowing from the receiver 115 to the medium pump 111 under the control of the stop control unit 123. As the downstream valve 121, a ball valve having high closing performance can be preferably used. However, the downstream valve 121 may be a gate valve or a butterfly valve.

The upstream valve 122 is attached to the circulation flow path 110 on the downstream side of the condenser 114 and on the upstream side of the receiver 115. The upstream valve 122 is electrically connected to the stop control unit 123. The upstream valve 122 is configured to open and close the flow path of the working medium flowing from the condenser 114 to the receiver 115 under the control of the stop control unit 123. As the upstream valve 122, a ball valve having high closing performance can be preferably used. However, the upstream valve 122 may be a gate valve or a butterfly valve.

The pressure detection unit 124 and the temperature detection unit 125 are attached to the circulation flow path 110 on the downstream side of the evaporator 112 and the upstream (suction) side of the expander 113. The pressure detection unit 124 and the temperature detection unit 125 are configured to detect the pressure and temperature of the working medium flowing from the evaporator 112 to the expander 113, respectively. The pressure detection unit 124 and the temperature detection unit 125 are configured to generate detection signals representing the detected pressure and temperature, respectively. The pressure detection unit 124 and the temperature detection unit 125 are electrically connected to the stop control unit 123 so that these detection signals are input to the stop control unit 123.

The temperature detection unit 126 is attached to the flow path of the cooling fluid so as to detect the temperature of the cooling fluid flowing from the refrigerant pump toward the condenser 114. The temperature detection unit 126 is configured to generate a detection signal representing the detected temperature. The temperature detection unit 126 is electrically connected to the stop control unit 123 so that the detection signal is input to the stop control unit 123.

The bypass flow path 127 branches from the circulation flow path 110 in the flow path section between the evaporator 112 and the expander 113, and the downstream end of the bypass flow path 127 is the flow between the expander 113 and the condenser 114. It is connected to the circulation flow path 110 in the road section.

The on-off valve 128 is attached to the bypass flow path 127. The on-off valve 128 is electrically connected to the stop control unit 123, and is configured to close or open the bypass flow path 127 under the control of the stop control unit 123.

The stop control unit 123 is configured to receive various external signals in addition to the above-mentioned detection signals. When the external signal requests the stop operation of the heat recovery device 100, the stop control unit 123 sends a control signal to the medium pump 111, the cooling pump 117, the downstream valve 121, and the upstream valve 122 according to a predetermined control program. It is configured to generate and output. The stop operation of the heat recovery device 100 is controlled based on the control signal from the stop control unit 123. The stop control unit 123 may be a signal generation circuit generated so as to generate a control signal according to a predetermined control program.

The external signal requesting the stop operation of the heat recovery device 100 may be a signal emitted from various sensors provided for detecting the presence or absence of an abnormality in the heat recovery device 100, or the heat recovery device 100 may be used. It may be generated according to the operation of the operator who operates it.

Before the stop operation of the heat recovery device 100 is required, in the heat recovery device 100, the working medium circulates along the circulation flow path 110, and the heat recovery operation for recovering heat from the heat source is performed. While the heat recovery operation is being performed, both the downstream valve 121 and the upstream valve 122 are in the open state. On the other hand, the on-off valve 128 is closed. During this time, the medium pump 111 and the cooling pump 117 discharge the working medium and the cooling fluid, respectively.

The working medium discharged from the medium pump 111 flows into the evaporator 112. The working medium exchanges heat with the heat source in the evaporator 112. As a result, the working medium evaporates and the temperature of the heat source decreases. The gas phase working medium flowing out of the evaporator 112 flows into the expander 113.

The internal rotor of the inflator 113 rotates under the expansion action of the working medium in the inflator 113. As a result, the generator 116 connected to the internal rotor generates electricity. The working medium after working in the inflator 113 flows into the condenser 114.

The working medium flowing into the condenser 114 exchanges heat with the cooling fluid supplied from the cooling pump 117. As a result, the temperature of the working medium is lowered and the working medium is condensed, while the temperature of the cooling fluid is raised. The working medium condensed as a result of the temperature drop flows into the receiver 115 and is stored in the receiver 115.

The working medium stored in the receiver 115 is sucked out by the medium pump 111 and supplied again to the evaporator 112.

The operation when the heat recovery device 100 is stopped will be described with reference to FIGS. 1 and 2. FIG. 2 is a schematic flowchart showing the control process of the stop control unit 123. Even in the stopped operation of the heat recovery device 100, the heat source continuously or intermittently flows into the evaporator 112.

The above-mentioned heat recovery operation is continued until the stop control unit 123 receives an external signal requesting the stop operation of the heat recovery device 100 (step S110). When the stop control unit 123 receives an external signal requesting the stop operation of the heat recovery device 100 (step S120), the stop control unit 123 starts the stop control for the stop operation of the heat recovery device 100. First, the stop control unit 123 generates a control signal for stopping the medium pump 111, a control signal for closing the downstream valve 121, and a control signal for opening the on-off valve 128. These control signals are output to the medium pump 111, the downstream valve 121, and the on-off valve 128 (step S130). The medium pump 111 stops in response to a control signal from the stop control unit 123. The downstream valve 121 closes in response to a control signal from the stop control unit 123. The on-off valve 128 opens in response to a control signal from the stop control unit 123. The on-off valve 128 is maintained in an open state until the stop operation of the heat recovery device 100 is completed. The stop timing of the medium pump 111 may be before or after the time when the downstream valve 121 closes. Alternatively, the medium pump 111 may stop at the same time as the downstream valve 121 closes.

Since the medium pump 111 is stopped and the downstream valve 121 is also closed, the inflow of the working medium into the evaporator 112 is stopped. Since the supply of the heat source to the evaporator 112 continues, the amount of the working medium in the evaporator 112 decreases as the working medium in the evaporator 112 is vaporized by the heat source.

While the medium pump 111 is stopped, the cooling pump 117 continues to supply the cooling fluid to the condenser 114 in order to continue the condensation of the working medium. As a result of the condenser 114 continuing to condense the working medium, the working medium of the liquid phase flows out of the condenser 114. The upstream valve 122 remains open to allow the working medium to flow from the condenser 114 to the receiver 115.

After outputting the control signal to the medium pump 111 and the downstream valve 121, the stop control unit 123 refers to the pressure and temperature represented by the detection signals from the pressure detection unit 124 and the temperature detection unit 126, and sets the upstream valve 122. It is determined whether or not a predetermined condition for changing from the open state to the closed state (hereinafter, referred to as “blocking condition”) is satisfied (step S140). The stop control unit 123 calculates the saturation temperature of the working medium based on the detection signal from the pressure detection unit 124. As the amount of evaporation of the working medium in the evaporator 112 decreases, the pressure detected by the pressure detector 124 decreases. As a result of the pressure drop, the calculated value of the saturation temperature also shows a decreasing tendency.

The stop control unit 123 refers to the detection signal from the temperature detection unit 126 and determines whether the saturation temperature of the working medium is substantially the same as the temperature of the cooling fluid (in other words, has it dropped to the temperature of the cooling fluid). Is repeatedly determined. When the saturation temperature of the working medium becomes substantially the same as the temperature of the cooling fluid, the working medium is condensed in the condenser 114 at once. The working medium that has flowed into the receiver 115 is stored in the receiver 115.

When it is determined that the saturation temperature of the working medium becomes substantially the same as the temperature of the cooling fluid, the stop control unit 123 generates a control signal for closing the upstream valve 122. The control signal is output from the stop control unit 123 to the upstream valve 122. The upstream valve 122 is closed in response to the control signal (step S150).

The stop control unit 123 may execute the control for stopping the cooling pump 117 in parallel with the control for closing the upstream valve 122. In this case, the stop control unit 123 generates a control signal for stopping the cooling pump 117, and the cooling pump 117 stops in response to the control signal.

The process of determining whether or not the closing condition is satisfied (step S140) may be performed based on the relationship between the pressure of the working medium and the saturated vapor pressure. Specifically, the stop control unit 123 acquires the temperature of the cooling fluid from the temperature detection unit 126, and calculates the saturated vapor pressure of the working medium when the temperature of the working medium becomes equal to the temperature of the cooling fluid. In the stop control unit 123, is the pressure detected by the pressure detection unit 124 (that is, the pressure of the working medium) substantially the same as the calculated saturated vapor pressure described above (in other words, up to the saturated vapor pressure described above)? Whether or not it has decreased) is repeatedly determined. When it is determined that the pressure of the working medium becomes substantially the same as the saturated vapor pressure of the working medium, a control signal for closing the upstream valve 122 is generated.

As a result of the processing shown in FIG. 2, when the heat recovery device 100 is stopped, most of the working medium used for the heat recovery operation of the heat recovery device 100 is confined in the receiver 115. .. As a result, it is possible to prevent the working medium from leaking from the circulation flow path 110 after the heat recovery device 100 is stopped.

Since the working medium is collected in the receiver 115, a dedicated collecting cylinder for collecting the working medium becomes unnecessary. Therefore, it is not necessary to remove the working medium from the heat recovery device 100 to the recovery cylinder and to manage the recovery cylinder after the working medium is recovered.

When the working medium is to be recovered by using the recovery cylinder, it is necessary to manage the recovery cylinder separately from the inspection of the heat recovery device 100 after the stop. On the other hand, in the present embodiment, it is possible to check whether or not the working medium is properly stored in the receiver 115 through the inspection of the receiver 115.

As described above, the working medium collected in the receiver 115 by closing the upstream valve 122 is not opened to the circulation flow path 110 for an unnecessarily long period of time. Therefore, the return of the working medium from the receiver 115 to the circulation flow path 110 is suppressed.

When an external signal requesting the stop of the heat recovery device 100 is input to the stop control unit 123, the downstream valve 121 is closed. Therefore, the working medium stored in the receiver 115 does not flow downstream.

In the present embodiment, the height position of the accommodation space in the receiver 115 overlaps the heat exchange section of the evaporator 112 when viewed in the horizontal direction. If the downstream valve 121 were not present, even if the medium pump 111 was stopped, the hydraulic head of the working medium in the receiver 115 could cause the working medium to flow into the evaporator 112. Then, if the supply of the heat source to the evaporator 112 is continued, the evaporation of the working medium in the evaporator 112 is also continued, and the pressure in the pipe downstream of the evaporator 112 becomes high. On the other hand, in the present embodiment, the downstream valve 121 is closed to prevent a new inflow of the working medium into the evaporator 112, and the pressurization in the evaporator 112 is suppressed.

It should be understood that the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is shown not by the above description but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

Regarding the above-described embodiment, the heat recovery device 100 may have a superheater or a preheater.

With respect to the above embodiment, in step S150, the cooling pump 117 is stopped. However, the operation of the cooling pump 117 may be continued even after the closing condition is satisfied. In this case, the stop control for the cooling pump 117 may be executed when an external signal requesting the stop of the cooling pump 117 is input to the stop control unit 123.

In step S140, when it is determined that the pressure detected by the pressure detection unit 124 is substantially equal to the calculated saturated vapor pressure, step S150 is executed.

Regarding the above-described embodiment, the temperature of the cooling fluid is detected by the temperature detection unit 126. However, as shown in FIG. 3, instead of the temperature detection unit 126, an ambient temperature detection unit 129 that detects the ambient temperature (hereinafter, referred to as ambient temperature) of the heat recovery device 100 may be used. .. The ambient temperature detection unit 129 is arranged so as to detect the ambient temperature of the heat recovery device 100. The ambient temperature detection unit 129 is configured to generate a detection signal representing the detected ambient temperature. The ambient temperature detection unit 129 is electrically connected to the stop control unit 123, and the detection signal is output from the ambient temperature detection unit 129 to the stop control unit 123.

The stop control unit 123 compares the temperatures represented by the detection signals output from the temperature detection unit 125 and the ambient temperature detection unit 129 in step S140 described with reference to FIG. The stop control unit 123 determines whether or not these temperatures are substantially equal. In addition, the stop control unit 123 calculates the degree of superheat of the working medium by using the detection signals output from the pressure detection unit 124 and the temperature detection unit 125. The stop control unit 123 determines whether or not the calculated degree of superheat is 0 ° C. or higher. In these determination processes, if it is determined that the temperatures detected by the temperature detection unit 125 and the ambient temperature detection unit 129 are substantially equal and the degree of superheat is 0 ° C. or higher, step S150 is executed. To. In other cases, the determination process of step S140 is repeated.

If the temperature of the working medium is substantially equal to the ambient temperature of the heat recovery device 100 and the degree of superheat of the working medium is 0 ° C. or higher, it can be seen that the working medium is almost condensed in the condenser 114.

When this state is obtained, most of the working medium in the heat recovery device 100 will be collected in the receiver 115.

The ambient temperature detection unit 129 may be used together with the temperature detection unit 126. In this case, the determination process using the detection signal from the ambient temperature detection unit 129 and the determination process using the detection signal from the temperature detection unit 126 may be performed in parallel. If a determination result that the blocking condition is satisfied is obtained in at least one of these determination processes, step S150 is executed.

The stop control unit 123 may more simply determine that the closing condition is satisfied when the temperature detected by the temperature detection unit 125 drops to the ambient temperature. Further, the stop control unit 123 may calculate the saturated vapor pressure of the working medium corresponding to the ambient temperature based on the ambient temperature detected by the ambient temperature detection unit 129. When the pressure detected by the pressure detection unit 124 drops to the calculated saturated vapor pressure, the stop control unit 123 may determine that the closing condition is satisfied.

In the above embodiment, as shown in FIG. 4, the upstream valve 122 may be closed based on the liquid level gauge 130 (float switch) that detects the liquid level of the working medium in the receiver 115.

The liquid level gauge 130 is configured to generate a detection signal indicating that the liquid level has reached a predetermined threshold value (height) when the liquid level of the working medium in the receiver 115 reaches a predetermined height. Has been done. The liquid level gauge 130 is electrically connected to the stop control unit 123. The liquid level at which the liquid level gauge 130 generates a detection signal is set at the height position of the liquid level obtained when a considerable part of the entire working medium in the heat recovery device 100 is housed in the receiver 115. There is.

When the liquid level of the working medium in the receiver 115 reaches a predetermined height, a detection signal is output from the liquid level meter 130 to the stop control unit 123. When the stop control unit 123 receives the detection signal from the liquid level gauge 130, the stop control unit 123 determines that the blocking condition in step S140 has been satisfied.

When the liquid level gauge 130 is used, the amount of working medium collected in the receiver 115 is directly detected by the liquid level gauge 130. Therefore, a predetermined amount of the working medium is collected in the receiver 115 without being influenced by the state of the working medium (temperature and pressure of the working medium), the temperature of the cooling fluid, and the temperature around the heat recovery device 100.

The liquid level gauge 130 may be used together with the pressure detection unit 124, the temperature detection units 125, 126 and / or the ambient temperature detection unit 129. Step S150 may be executed when a determination result that the blocking condition is satisfied is obtained in any of the above-mentioned determination processes using these detection devices.

Instead of various determination processes relating to whether or not the closure condition is satisfied, the elapsed period from the closing of the downstream valve 121 may be used for the determination processing of the closure condition. When the elapsed period exceeds a predetermined threshold value, the stop control unit 123 may determine that the closing condition is satisfied.

The technique of the above-described embodiment is suitably used for various applications in which heat is recovered from a heat source and the recovered heat energy is used to obtain power.

100 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Heat recovery device 111 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Media pump 112 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ Evaporator 113 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Expander 114 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ Receiver 117 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Cooling pump 121 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Downstream valve 122 ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Upstream valve 123 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Stop control unit

Claims (9)

A heat recovery device that recovers the heat of a heat source.
A circulation flow path configured to allow the working medium delivered by the medium pump to pass through the evaporator, expander, condenser, and receiver in that order and then returned to the medium pump.
A cooling pump that supplies a cooling fluid that condenses the working medium under heat exchange with the working medium to the condenser.
An upstream valve that opens and closes the circulation flow path between the receiver and the condenser,
A downstream valve that opens and closes the circulation flow path between the receiver and the medium pump,
A stop control unit for controlling the stop operation of the heat recovery device is provided.
The cooling pump continues to supply the cooling fluid to the condenser even after the start of the stop operation.
The stop control unit is a heat recovery device that stops the medium pump, closes the downstream valve, and closes the upstream valve when a preset condition is satisfied after the downstream valve is closed. The heat recovery device according to claim 1, wherein at least a part of the evaporator overlaps a storage space in which the working medium is stored in the receiver. The preset conditions are that the saturation temperature of the working medium in the flow path through which the working medium flows toward the condenser is lowered to the temperature of the cooling fluid, or the pressure of the working medium is the said. The heat recovery device according to claim 1 or 2, wherein the temperature of the working medium is lowered to the saturated vapor pressure of the working medium when the temperature of the cooling fluid is the same as the temperature of the cooling fluid. In the preset conditions, the temperature of the working medium in the flow path through which the working medium flows toward the condenser is substantially the same as the temperature around the heat recovery device, and the temperature in the flow path is substantially the same. The heat recovery device according to any one of claims 1 to 3, wherein the degree of superheat of the working medium is 0 ° C. or higher. The heat recovery device according to any one of claims 1 to 4, wherein the preset condition is that the liquid level in the working medium in the receiver reaches a predetermined threshold value. The heat supplied to the evaporator is circulated so as to be returned to the medium pump after the working medium sent out by the medium pump is passed through the evaporator, the expander, the condenser and the receiver in this order, and the heat supplied to the evaporator is circulated. It is a method of collecting the working medium in the heat recovery device to be recovered by the pump.
To stop the medium pump and stop the outflow of the working medium from the receiver to the medium pump.
By continuing to supply the cooling fluid to the condenser even after the medium pump is stopped, the condensation of the working medium in the condenser can be continued.
After stopping the outflow of the working medium from the receiver, when the preset conditions are met, stopping the outflow of the condensed working medium from the condenser to the receiver. How to collect the working medium. The preset conditions are that the saturation temperature of the working medium in the flow path through which the working medium flows toward the condenser is lowered to the temperature of the cooling fluid, or the temperature of the working medium is cooled. The collection method according to claim 6, wherein the pressure of the working medium is reduced to the saturated vapor pressure of the working medium at the same temperature as the fluid. In the preset conditions, the temperature of the working medium in the flow path through which the working medium flows toward the condenser is substantially the same as the temperature around the heat recovery device, and the temperature in the flow path is substantially the same. The collection method according to claim 6 or 7, wherein the superheat degree of the working medium is 0 ° C. or higher. The collection method according to any one of claims 6 to 8, wherein the preset condition is that the liquid level in the working medium in the receiver reaches a predetermined threshold value.

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