WO2012039225A1

WO2012039225A1 - Rankine cycle device

Info

Publication number: WO2012039225A1
Application number: PCT/JP2011/068981
Authority: WO
Inventors: 村上　和朗; 井口　雅夫; 英文森; 榎島　史修
Original assignee: 株式会社豊田自動織機
Priority date: 2010-09-24
Filing date: 2011-08-23
Publication date: 2012-03-29
Also published as: JP2012067687A

Abstract

Disclosed is a Rankine cycle device including a waste heat source, an operating fluid circuit, and a limiting unit. The operating fluid circuit is configured by sequentially connecting a pump, a heat exchanger, an expander, and a condenser. The pump delivers under pressure the operating fluid. The heat exchanger subjects the operating fluid, which is delivered from the pump under pressure, to heat exchange with waste heat from the waste heat source. The expander outputs mechanical energy by expanding the operating fluid having been subjected to the heat exchange at the heat exchanger. The condenser condenses the operating fluid expanded by the expander. The limiting unit limits the amount of heat which, on the basis of temperature information detected at the inlet of the pump or the inlet of the expander, the operating fluid receives in the portion of the operating fluid circuit which extends from the outlet of the pump to the inlet of the expander.

Description

Rankine cycle equipment

The present invention relates to a Rankine cycle device including a working fluid circuit in which a pump, a heat exchanger, an expander, and a condenser are sequentially connected.

As this type of Rankine cycle apparatus, for example, the Rankine cycle apparatus disclosed in Patent Document 1 can be cited. The Rankine cycle apparatus of Patent Document 1 is configured by connecting a pressure feed pump, a regenerative heat exchanger, an evaporator, an expander, and a condenser in order through a flow path. The working fluid pumped from the pump is heated by the regenerative heat exchanger and then further heated by the evaporator.

JP 2009-138684 A

In the Rankine cycle device of Patent Document 1, the amount of heat (the amount of heat absorbed by the working fluid) of the working fluid immediately after passing through the evaporator and before being sucked into the expander may be excessive. And if the heat quantity of the working fluid at the outlet of the expander is excessive and exceeds the heat dissipation capacity of the condenser, the heat of the working fluid cannot be thrown away by the condenser and it operates in the condenser. Cavitation occurs at the inlet of the pressure pump because the fluid is mixed with gas and liquid. In order to prevent the occurrence of cavitation, the heat dissipation capability of the condenser must be increased. If the heat dissipation capability is increased, the size of the condenser will increase, leading to an increase in cost. In addition, if the amount of heat in the working fluid before being sucked into the expander becomes excessive, the suction temperature at the expander inlet becomes too high, and the expander must adopt a heat-resistant design, increasing costs. It will lead to.

An object of the present invention is to provide a Rankine cycle device capable of limiting the amount of heat received by the working fluid between the outlet of the pump and the inlet of the expander.

In order to achieve the above object, according to one aspect of the present invention, a Rankine cycle device including a waste heat source, a working fluid circuit, and a limiting unit is provided. The working fluid circuit is configured by sequentially connecting a pump, a heat exchanger, an expander, and a condenser. The pump pumps the working fluid. The heat exchanger causes the working fluid pumped from the pump to exchange heat with waste heat from the waste heat source. The expander expands the working fluid heat-exchanged by the heat exchanger and outputs mechanical energy. The condenser condenses the working fluid expanded by the expander. The restricting unit is configured to provide the working fluid between the outlet of the pump and the inlet of the expander on the working fluid circuit based on temperature information detected at the inlet of the pump or the inlet of the expander. Limit the amount of heat received.

According to this, by providing the limiting portion in the Rankine cycle device, the amount of heat (amount of heat absorbed) received by the working fluid between the outlet of the pump and the inlet of the expander can be limited, and is sucked into the expander. It is possible to prevent an excessive amount of heat from the working fluid before the operation. And since a part of heat amount which a working fluid has is taken out as mechanical energy with an expander, the heat amount which a working fluid has at an expander exit will decrease from the heat amount which it had at an expander entrance. For this reason, it is prevented that the calorie | heat_amount which a working fluid has at an expander exit exceeds the heat dissipation capability of a condenser, and a working fluid can be liquefied with a condenser. As a result, the working fluid can be prevented from becoming a gas-liquid mixed state in the condenser, cavitation can be prevented from occurring at the pump inlet, and the condenser can be enlarged to prevent cavitation. There is no need. In addition, by providing a restriction part in the Rankine cycle device, it is possible to prevent the amount of heat of the working fluid before inhaling the expander from being excessive, so that the intake temperature at the expander inlet becomes too high. This eliminates the need to adopt a heat resistant design for the expander.

Preferably, the Rankine cycle apparatus further includes a waste heat path through which a waste heat medium flows. Waste heat from the waste heat source is transferred to the waste heat medium. In the heat exchanger, heat is exchanged between the waste heat medium and the working fluid. The restriction unit is a heat exchanger bypass passage provided so that at least a part of the waste heat medium flowing through the waste heat path bypasses the heat exchanger.

According to this, the amount of the waste heat medium that can exchange heat with the working fluid in the heat exchanger by bypassing the heat exchanger with a part of the waste heat medium flowing through the waste heat path by the heat exchanger bypass passage. And the amount of heat the working fluid receives in the heat exchanger can be limited (reduced).

Preferably, the waste heat path is a cooling medium circulation circuit that circulates a cooling medium that cools the waste heat source. The waste heat medium is the cooling medium.

According to this, a part of the cooling medium that has received heat by heat exchange with the waste heat source can be bypassed by the heat exchanger bypass passage. For this reason, the amount of the cooling medium that can exchange heat with the working fluid in the heat exchanger can be reduced, and the amount of heat received by the working fluid in the heat exchanger can be limited (reduced).

Preferably, the restriction portion is a heat exchanger bypass passage provided so that at least a part of the working fluid flowing in the working fluid circuit bypasses the heat exchanger.

According to this, a part of the working fluid circulating in the working fluid circuit is bypassed by the heat exchanger by the heat exchanger bypass passage, thereby reducing the amount of the working fluid that can be heat exchanged by the heat exchanger, and the working fluid. The amount of heat received from the heat exchanger can be reduced.

Preferably, based on the suction temperature of the working fluid at the inlet of the expander as the temperature information, the degree of superheat at the inlet of the expander, or the degree of supercooling at the inlet of the pump, the heat exchanger Adjust the opening of the bypass passage.

According to this, it is possible to clearly grasp whether or not the amount of heat (absorption amount) of the working fluid is excessive by using each temperature information.

Preferably, the heat exchanger has a first heat exchanger that exchanges heat with the working fluid pumped by the pump, and a second heat exchange that exchanges heat with the working fluid that has exchanged heat with the first heat exchanger. Including The restriction portion is a throttle whose opening degree can be adjusted provided in a portion of the working fluid circuit downstream of the first heat exchanger and upstream of the second heat exchanger. Preferably, the opening degree of the throttle is adjusted so that the pressure of the working fluid that has passed through the first heat exchanger is higher than the saturation pressure of the working fluid at the waste heat medium temperature of the first heat exchanger. To do.

According to this, the amount of heat that can be received by the working fluid in the first heat exchanger can be reduced by increasing the pressure of the working fluid at the pump outlet by the throttle. As a result, the amount of heat of the working fluid that has passed through the second heat exchanger can be reduced.

Preferably, based on the suction temperature of the working fluid at the inlet of the expander as the temperature information, the degree of superheat at the inlet of the expander, or the degree of supercooling at the inlet of the pump, the opening of the throttle is preferably determined. Adjust the degree.

According to this, it is possible to clearly grasp whether or not the amount of heat (heat absorption amount) of the working fluid is excessive by using each temperature information.

Preferably, the pump is driven according to the rotational speed of an external drive source.

According to this, by providing the limiting portion in the Rankine cycle device, the amount of heat (amount of heat absorbed) received by the working fluid between the outlet of the pump and the inlet of the expander can be limited, and is sucked into the expander. The temperature of the working fluid before the operation can be lowered. Therefore, in order to lower the suction temperature at the inlet of the expander, it is not necessary to increase the flow rate of the working fluid autonomously by increasing the rotation speed of the pump, and the Rankine cycle device uses a pump that cannot adjust the flow rate autonomously. Even so, the suction temperature of the expander can be lowered.

(A) is a schematic diagram which shows the Rankine cycle apparatus which concerns on the 1st Embodiment of this invention. (B) is a figure which shows the change of the enthalpy and pressure in a Rankine cycle apparatus. (A) is a schematic diagram which shows the Rankine cycle apparatus which concerns on 2nd Embodiment. (B) is a figure which shows the change of the enthalpy and pressure in a Rankine cycle apparatus. (A) is a schematic diagram which shows the Rankine-cycle apparatus which concerns on 3rd Embodiment. (B) is a figure which shows the change of the enthalpy and pressure in the conventional Rankine cycle apparatus. (C) is a figure which shows the change of the enthalpy and pressure in the Rankine cycle apparatus of 3rd Embodiment. The figure which shows the Rankine-cycle apparatus which applied the exhaust gas circuit as another example of a waste heat path. The figure which shows the Rankine cycle apparatus which made temperature information detectable by a supercooling degree.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIG.

As shown to Fig.1 (a), Rankine cycle apparatus 10 connects the expander 20, the condenser 30, the pump 40, and the boiler 50 as a heat exchanger by the

flow path

11, 14, 15, 16 sequentially. A refrigerant circulation circuit 12 is provided as a working fluid circuit. In the refrigerant circulation circuit 12, the refrigerant circulates as a working fluid. In the refrigerant circulation circuit 12, the refrigerant flows through the refrigerant circulation circuit 12 along the arrangement order of the expander 20, the condenser 30, the pump 40, and the boiler 50. The direction in which the refrigerant flows is the refrigerant circulation direction. In the pump 40, a drive shaft (not shown) is operatively connected to an external drive source Fb via a pulley Fa. Therefore, the driving force of the external drive source Fb is directly transmitted to the pump 40 via the pulley Fa, and the pump 40 is always rotated when the external drive source Fb is rotated. For this reason, the pump 40 is driven according to the rotational speed of the external drive source Fb, and the pump 40 itself cannot adjust the rotational speed, so that the flow rate cannot be adjusted autonomously.

A boiler 50 is connected to a discharge port (not shown) that is an outlet of the pump 40 via the first flow path 11. The boiler 50 is provided on a cooling medium circulation circuit 52 as a waste heat path connected to the waste heat source 51. Waste heat from the waste heat source 51 is transmitted (heat exchanged) to a cooling medium (cooling water in this embodiment) as a waste heat medium circulating in the cooling medium circulation circuit 52, and by the heat transfer (heat exchange) The waste heat source 51 is cooled. Then, the cooling water heated by receiving the waste heat from the waste heat source 51 circulates in the cooling medium circulation circuit 52 along the direction indicated by the arrow Y in FIG. The refrigerant discharged from the pump 40 is heated by heat exchange in the boiler 50 with the cooling water to which the waste heat is transmitted from the waste heat source 51.

A suction port (not shown) that is the inlet of the expander 20 is connected to the boiler 50 via the second flow path 14, and the refrigerant heated by the boiler 50 passes through the second flow path 14 and the suction port. Via the expander 20. And the refrigerant | coolant which expand | swelled with the expander 20 and a part of calorie | heat_amount which a refrigerant | coolant has was taken out as mechanical energy, and it temperature-falls and pressure-reduced is the 3rd flow path 15 and the suction port (not shown) from the exit of the expander 20. It is sucked into the condenser 30 via the. A suction port (not shown) that is an inlet of the pump 40 is connected to the discharge port (not shown) of the condenser 30 via the fourth flow path 16. In the condenser 30, the refrigerant is condensed to change into a liquid refrigerant, and the liquid refrigerant is sucked into the pump 40 through the fourth flow path 16 and the suction port.

In the cooling medium circulation circuit 52, a position downstream from the boiler 50 and upstream from the waste heat source 51 and a position downstream from the waste heat source 51 and upstream from the boiler 50 are a heat exchanger bypass passage 53 as a limiting unit. Connected by. On the heat exchanger bypass passage 53, an opening / closing valve 54 is provided as a restricting portion, and the opening degree of the heat exchanger bypass passage 53 can be adjusted by the opening / closing valve 54. When the on-off valve 54 is in the closed state, all of the cooling water heat exchanged by the waste heat source 51 flows toward the boiler 50. On the other hand, when the on-off valve 54 is in the open state, a part of the cooling water exchanged by the waste heat source 51 flows through the heat exchanger bypass passage 53 and the remaining cooling water flows toward the boiler 50 as a cooling medium circulation circuit. Flow through 52. The cooling water that has flowed through the boiler 50 and the cooling water that has flowed through the heat exchanger bypass passage 53 are merged near the outlet of the heat exchanger bypass passage 53 and flow toward the waste heat source 51.

Further, a temperature sensor S is provided on the flow path 14 located downstream of the boiler 50 and upstream of the expander 20 (near the inlet) in the refrigerant circulation direction in the refrigerant circulation circuit 12. The temperature sensor S detects the suction temperature at the inlet of the expander 20 and detects the suction temperature as temperature information. The temperature sensor S is signal-connected to the control unit 73. Then, the control unit 73 adjusts the opening degree of the heat exchanger bypass passage 53 by adjusting the opening / closing of the on-off valve 54 based on the temperature information detected by the temperature sensor S.

The opening degree adjustment of the on-off valve 54 is performed to limit the amount of heat (heat absorption amount) received by the refrigerant in the boiler 50. This restriction on the amount of heat is performed so that the amount of heat of the refrigerant at the outlet of the expander 20 does not exceed the heat dissipation capability at the outlet of the condenser 30. Specifically, the opening degree of the on-off valve 54 is adjusted in order to prevent the gas-liquid mixture state of the refrigerant in the condenser 30 from occurring. As the opening degree of the on-off valve 54 becomes smaller, the flow rate of the cooling water flowing to the boiler 50 increases. Therefore, the amount of heat that can be received by the boiler 50 increases, and the opening degree of the on-off valve 54 becomes larger. Since the flow rate of the cooling water flowing through the boiler 50 decreases, the amount of heat that the refrigerant can receive in the boiler 50 decreases.

In order to prevent the heat quantity of the refrigerant at the outlet of the expander 20 from exceeding the heat dissipation capability of the condenser 30, the control unit 73 opens the on-off valve 54 with respect to temperature information (suction temperature of the expander 20). A map in which the degrees are associated is stored in advance. The temperature of the refrigerant immediately after passing through the boiler 50 indirectly represents the heat absorption amount of the refrigerant in the boiler 50. Then, the opening degree of the on-off valve 54 is obtained in advance by experiments so that the heat quantity of the refrigerant at the outlet of the expander 20 does not exceed the heat dissipation capacity in the condenser 30 with respect to the temperature information. The control unit 73 is signal-connected to the on-off valve 54 so that the opening degree of the on-off valve 54 can be controlled.

FIG. 1B shows changes in the enthalpy and pressure of the refrigerant in the Rankine cycle apparatus 10 of the first embodiment. In FIG. 1B, the horizontal axis represents enthalpy, the vertical axis represents pressure, and the curve E represents a saturated liquid line and a saturated vapor line. Note that enthalpy is the amount of internal pressure added to the product of refrigerant pressure and volume, and the amount of heat entering and exiting the refrigerant is equal to the amount of change in enthalpy under constant pressure conditions. The quantity indicates the amount of change in the heat quantity of the refrigerant.

1B, a solid line G1 from the intersection M1 to the intersection M2 represents a condensation stroke by the condenser 30, and a solid line G2 from the intersection M2 to the intersection M3 represents a pumping stroke by the pump 40. A solid line G3 from the intersection M3 to the intersection M4 represents a heating stroke by the boiler 50, and a solid line G4 from the intersection M4 to the intersection M1 represents an expansion stroke by the expander 20. The solid lines G1 to G4 indicate the change in the enthalpy and pressure of the refrigerant in the Rankine cycle device 10 according to the first embodiment.

Further, a straight line obtained by combining the two-dot chain line G5 from the intersection point M5 to the intersection point M1 in the two-dot chain line in FIG. 1B and the above-described solid line G1 is a case where the heat exchanger bypass passage 53 and the on-off valve 54 are not provided. Indicates the condensation process. Further, a straight line obtained by combining the two-dot chain line G6 from the intersection point M6 to the intersection point M4 and the above-described solid line G3 indicates a heating stroke when the heat exchanger bypass passage 53 and the on-off valve 54 are not provided. A two-dot chain line G7 from the intersection point M6 to the intersection point M5 indicates an expansion stroke when the heat exchanger bypass passage 53 and the on-off valve 54 are not provided. Further, the amount of enthalpy increase in the boiler 50 in the first embodiment (the length of the solid line G3) is Δh11, and the amount of enthalpy increase in the boiler 50 when the heat exchanger bypass passage 53 and the on-off valve 54 are not provided ( The total length of the solid line G3 and the two-dot chain line G6) is Δh12.

Now, in the Rankine cycle device 10 of the first embodiment, the control unit 73 adjusts the opening degree of the on-off valve 54 with reference to a map based on the temperature information detected by the temperature sensor S. That is, the amount of heat absorbed by the boiler 50 becomes excessive, the temperature of the refrigerant before being sucked into the expander 20 is high, and the amount of heat of the refrigerant at the outlet of the expander 20 exceeds the heat dissipation capability of the condenser 30. If so, the controller 73 opens the on-off valve 54 and adjusts its opening.

Then, a part of the cooling water flowing through the cooling medium circulation circuit 52 flows through the heat exchanger bypass passage 53 and the remaining cooling water flows toward the boiler 50. As a result, the flow rate of the cooling water flowing toward the boiler 50 is reduced, and the amount of heat received by the refrigerant from the boiler 50 is reduced as compared with the case where the on-off valve 54 is closed.

In the boiler 50, the refrigerant exchanges heat with the cooling water whose amount of heat has decreased. For this reason, as shown in FIG.1 (b), in Rankine cycle apparatus 10 of 1st Embodiment which provided the heat exchanger bypass passage 53 and the on-off valve 54, the enthalpy increase amount (heat absorption amount) in a heating process Is represented by Δh11. Therefore, in the Rankine cycle device 10 of the first embodiment, the enthalpy increase amount (heat absorption amount) Δh11 in the heating stroke is the enthalpy increase amount in the heating stroke when the heat exchanger bypass passage 53 and the on-off valve 54 are not provided. (Endothermic amount) Δh12 is smaller, indicating that the endothermic amount in the boiler 50 is decreasing. As a result, the temperature of the refrigerant before being sucked into the expander 20 becomes lower than that of the conventional Rankine cycle device.

According to the first embodiment, the following advantages can be obtained.

(1) In the Rankine cycle device 10, the cooling medium circulation circuit 52 of the waste heat source 51 is provided with a heat exchanger bypass passage 53 for bypassing the boiler 50, and an open / close valve 54 is provided in the heat exchanger bypass passage 53. The opening degree of the heat exchanger bypass passage 53 can be adjusted. The amount of heat that the refrigerant can receive in the boiler 50 can be limited by opening the on-off valve 54 and bypassing the boiler 50 with a part of the cooling water circulating in the cooling medium circulation circuit 52. Therefore, the amount of heat received by the refrigerant between the outlet of the pump 40 and the inlet of the expander 20 can be limited. As a result, after mechanical energy is taken out by the expander 20, it is possible to prevent the amount of heat of the refrigerant at the outlet of the expander 20 from exceeding the heat dissipation capability of the condenser 30. Can be liquefied. Thereby, it is possible to prevent the refrigerant in the gas-liquid mixed state from being supplied to the pump 40.

Therefore, according to the Rankine cycle device 10 of the first embodiment, by providing the heat exchanger bypass passage 53 and the on-off valve 54, the occurrence of cavitation at the inlet of the pump 40 is prevented, and the pumping capability of the refrigerant by the pump 40 is achieved. A decrease can be prevented. In order to prevent the occurrence of cavitation, it is not necessary to increase the size of the condenser 30 to increase the heat dissipation capability, and therefore, an increase in cost due to an increase in the size of the condenser 30 does not occur. In addition, it is possible to prevent the intake temperature of the expander 20 from becoming too high by reducing the amount of heat of the refrigerant before the expander 20 is sucked, and the cost is increased by adopting the heat resistant design of the expander 20. Does not occur.

(2) By providing the heat exchanger bypass passage 53 and the on-off valve 54 in the cooling medium circulation circuit 52, the amount of heat (heat absorption amount) received by the refrigerant in the boiler 50 can be limited. When the amount of heat of the refrigerant after passing through the boiler 50 is large and the suction temperature at the inlet of the expander 20 is high, it is conceivable to increase the flow rate by increasing the rotational speed of the pump 40 in order to lower the suction temperature. However, in the first embodiment, since the pump 40 is directly driven by the external drive source Fb and the flow rate cannot be autonomously adjusted, the rotational speed of the pump 40 cannot be increased and the suction temperature is lowered. I can't. However, in the first embodiment, by providing the heat exchanger bypass passage 53 and the on-off valve 54 in the cooling medium circulation circuit 52, it is possible to limit the amount of heat received by the refrigerant in the boiler 50, and the intake of the inlet of the expander 20 The temperature can be lowered. Therefore, the suction temperature of the expander 20 can be lowered even when the pump 40 that cannot autonomously adjust the flow rate is used in the Rankine cycle device 10.

(3) In order to liquefy all the refrigerant with the condenser 30 in order to prevent the occurrence of cavitation, it is conceivable to increase the pressure of the refrigerant in the condenser 30 and reduce the amount of heat released to liquefy the refrigerant. However, increasing the pressure of the refrigerant in the condenser 30 is not preferable because the mechanical energy output by the expansion of the refrigerant in the expander 20 is reduced. On the other hand, the Rankine cycle apparatus 10 is provided only with a restricting portion (a heat exchanger bypass passage 53 and an on-off valve 54) in order to liquefy all the refrigerant in the condenser 30, and the refrigerant in the condenser 30 There is no need to increase the pressure of the expander 20, and there is no decrease in mechanical energy output in the expander 20.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In the following description, the same components as those in the first embodiment already described are denoted by the same reference numerals, and the redundant description thereof is omitted or simplified.

As shown in FIG. 2A, in the Rankine cycle apparatus 10, the cooling medium circulation circuit 52 is not provided with the heat exchanger bypass passage 53 and the on-off valve 54. Further, in the refrigerant circulation direction in the refrigerant circulation circuit 12, a position downstream from the pump 40 and upstream from the boiler 50 and a position downstream from the boiler 50 and upstream from the expander 20 are defined as a restriction unit. It is connected by a boiler bypass passage 55 which is a heat exchanger bypass passage. On the boiler bypass passage 55, an opening / closing valve 56 is provided as a restricting portion, and the opening degree of the boiler bypass passage 55 can be adjusted by the opening / closing valve 56. When the on-off valve 56 is in the closed state, the refrigerant pumped from the pump 40 flows toward the boiler 50. On the other hand, when the on-off valve 56 is in the open state, a part of the refrigerant pumped from the pump 40 flows toward the boiler 50, and the remaining refrigerant flows through the boiler bypass passage 55. The refrigerant flowing through the boiler 50 and the refrigerant flowing through the boiler bypass passage 55 are merged in the vicinity of the outlet of the boiler bypass passage 55 and flow toward the expander 20.

A superheat degree sensor 57 is provided on the flow path 14 located downstream of the boiler 50 and upstream of the expander 20 (near the inlet) in the refrigerant circulation direction in the refrigerant circulation circuit 12. This superheat degree sensor 57 detects the superheat degree (difference between the temperature of superheated steam and the temperature of saturated steam (boiling point)) at the inlet of the expander 20 as temperature information. The superheat degree sensor 57 is signal-connected to the control unit 73, and the control unit 73 adjusts the opening degree of the on-off valve 56 based on temperature information (superheat degree) from the superheat degree sensor 57. This opening / closing adjustment of the on-off valve 56 is performed to limit the amount of heat (heat absorption amount) received by the refrigerant in the boiler 50.

If the amount of heat (heat absorption amount) received by the refrigerant in the boiler 50 becomes excessive, the degree of superheat of the refrigerant increases. If the heat absorption amount becomes excessive and the superheat degree exceeds a predetermined value, the heat amount of the refrigerant at the outlet of the expander 20 exceeds the heat dissipation capability in the condenser 30. Therefore, in the second embodiment, the opening degree of the on-off valve 56 is adjusted based on the temperature information from the superheat degree sensor 57 so that the superheat degree of the refrigerant after passing through the boiler 50 does not exceed a predetermined value. The amount of heat possessed by the refrigerant at the outlet 20 is prevented from exceeding the heat dissipation capability of the condenser 30.

As the opening degree of the on-off valve 56 increases, the amount of refrigerant flowing through the boiler bypass passage 55 increases and the amount of refrigerant flowing through the boiler 50 decreases, so the amount of heat that can be received by the boiler 50 decreases, and overheating The degree can be reduced. On the other hand, as the opening degree of the on-off valve 56 becomes smaller, the amount of refrigerant flowing into the boiler bypass passage 55 decreases and the amount of refrigerant flowing into the boiler 50 increases, so the amount of heat that can be received by the boiler 50 increases, and the degree of superheat Becomes bigger.

The controller 73 associates the opening degree of the on-off valve 56 with the temperature information (degree of superheat) so that the heat quantity of the refrigerant at the outlet of the expander 20 does not exceed the heat dissipation capability of the condenser 30. Maps are stored in advance.

FIG. 2B shows changes in the enthalpy and pressure of the refrigerant in the Rankine cycle apparatus 10 of the second embodiment. In FIG. 2B, the horizontal axis represents enthalpy, the vertical axis represents pressure, and the curve E represents a saturated liquid line and a saturated vapor line. Note that enthalpy is the amount of internal pressure added to the product of refrigerant pressure and volume, and the amount of heat entering and exiting the refrigerant is equal to the amount of change in enthalpy under constant pressure conditions. The quantity indicates the amount of change in the heat quantity of the refrigerant.

2B, a solid line K1 from the intersection H1 to the intersection H2 represents a condensation stroke by the condenser 30, and a solid line K2 from the intersection H2 to the intersection H3 represents a pumping stroke by the pump 40. A solid line K3 from the intersection H3 to the intersection H4 represents a heating stroke by the boiler 50, and a solid line K4 from the intersection H4 to the intersection H1 represents an expansion stroke by the expander 20. The solid lines K1 to K4 indicate changes in the enthalpy and pressure of the refrigerant in the Rankine cycle device 10 according to the second embodiment.

Further, the straight line obtained by combining the two-dot chain line K5 from the intersection point H5 to the intersection point H1 in the two-dot chain line in FIG. 2B and the solid line K1 described above is a condensation process when the boiler bypass passage 55 and the on-off valve 56 are not provided. Indicates. Furthermore, a straight line obtained by combining the two-dot chain line K6 from the intersection H6 to the intersection H4 and the above-described solid line K3 indicates a heating stroke when the boiler bypass passage 55 and the on-off valve 56 are not provided. A two-dot chain line K7 from the intersection H6 to the intersection H5 indicates an expansion stroke when the boiler bypass passage 55 and the on-off valve 56 are not provided. Further, the amount of enthalpy increase in the boiler 50 in the second embodiment (heat absorption amount: length of the solid line K3) is Δh21, and the amount of enthalpy increase in the boiler 50 when the boiler bypass passage 55 and the on-off valve 56 are not provided. (Endothermic amount: the total length of the solid line K3 and the two-dot chain line K6) is Δh22.

Now, in the Rankine cycle apparatus 10 of the second embodiment, the control unit 73 adjusts the opening degree of the on-off valve 56 from the map based on the temperature information detected by the superheat degree sensor 57. That is, when the degree of superheat of the refrigerant after passing through the boiler 50 is high (a large amount of heat absorption), and the amount of heat that the refrigerant has at the outlet of the expander 20 after mechanical energy is taken out exceeds the heat dissipation capability of the condenser 30, The control unit 73 opens the on-off valve 56 and adjusts the opening degree.

Then, a part of the refrigerant flowing through the refrigerant circulation circuit 12 flows through the boiler bypass passage 55 and the remaining refrigerant flows toward the boiler 50. Since the amount of refrigerant flowing through the boiler 50 is reduced, the amount of heat that can be received by the boiler 50 is reduced as compared with the case where the refrigerant does not flow through the boiler bypass passage 55. Therefore, when the refrigerant that has flowed through the boiler 50 and the refrigerant that has flowed through the boiler bypass passage 55 merge at the outlet of the boiler bypass passage 55, the amount of heat that the refrigerant has at that junction is that all the refrigerant passes through the boiler 50. Compared to when it flows (when the on-off valve 56 is closed), it decreases.

Therefore, as shown in FIG. 2B, in the Rankine cycle device 10 of the second embodiment provided with the boiler bypass passage 55 and the on-off valve 56, the enthalpy increase amount (heat absorption amount) in the heating stroke is Δh21. It is shown in Therefore, in the Rankine cycle device 10 of the second embodiment, the enthalpy increase amount Δh21 in the heating stroke is smaller than the enthalpy increase amount Δh22 in the heating stroke when the boiler bypass passage 55 and the on-off valve 56 are not provided. It is shown that the endothermic amount in the boiler 50 is decreasing. As a result, the temperature of the refrigerant immediately after passing through the boiler 50 is lower than the temperature of the refrigerant immediately after passing through the boiler 50 in a Rankine cycle device in which the boiler bypass passage 55 and the on-off valve 56 are not provided.

According to the second embodiment, in addition to the same advantages as (2) and (3) of the first embodiment, the following advantages can be obtained.

(4) In the Rankine cycle device 10, the refrigerant circulation circuit 12 is provided with a boiler bypass passage 55 for bypassing the boiler 50, and an open / close valve 56 is provided in the boiler bypass passage 55, so that the opening degree of the boiler bypass passage 55 is increased. Made adjustable. Then, by opening the on-off valve 56 and bypassing the boiler 50 with a part of the refrigerant circulating in the refrigerant circulation circuit 12, the amount of heat received by the refrigerant from the boiler 50 can be limited, and the expander is provided from the outlet of the pump 40. It is possible to limit the amount of heat received by the refrigerant up to 20 inlets. Accordingly, the amount of heat (heat absorption amount) of the refrigerant before the expander 20 is sucked can be reduced, and after the mechanical energy is taken out by the expander 20, the amount of heat of the refrigerant at the outlet of the expander 20 is reduced. It is possible to prevent the heat dissipation capacity from being exceeded. As a result, the refrigerant is liquefied by the condenser 30, and the pump 40 can be prevented from being supplied with the refrigerant in a gas-liquid mixed state.

Therefore, according to the Rankine cycle device 10 of the second embodiment, the provision of the boiler bypass passage 55 and the on-off valve 56 prevents the pump 40 from generating cavitation and prevents the pump 40 from reducing the pressure of the refrigerant. can do. In order to prevent the occurrence of cavitation, it is not necessary to increase the size of the condenser 30 to increase the heat dissipation capability, and therefore, an increase in cost due to an increase in the size of the condenser 30 does not occur. In addition, by reducing the amount of heat of the refrigerant immediately after passing through the boiler 50, the intake temperature of the expander 20 can be prevented from becoming excessively high, and an increase in cost due to the use of the heat resistant design of the expander 20 also occurs. Absent.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In the following description, the same components as those in the first embodiment already described are denoted by the same reference numerals, and the redundant description thereof is omitted or simplified.

As shown in FIG. 3A, in the refrigerant circulation circuit 12 of the Rankine cycle device 10, a first heat exchanger is connected to a discharge port (not shown) that is an outlet of the pump 40 via a first flow path 11. As a first boiler 64 is connected. The first boiler 64 is provided on a first cooling water circulation path 59 connected to an engine 58 as a waste heat source. A radiator 62 is provided on the first cooling water circulation path 59. Then, the waste heat from the engine 58 is transmitted, and the coolant as a waste heat medium that has cooled the engine 58 circulates through the first coolant circulation path 59 and serves as a heat source for the first boiler 64. Therefore, the refrigerant discharged from the outlet of the pump 40 receives heat from the cooling water by heat exchange with the cooling water in the first boiler 64 and is heated.

Further, an exhaust passage 66 for exhaust gas exhaust is connected to the engine 58, and exhaust gas as a waste heat medium to which waste heat from the engine 58 is transmitted flows through the exhaust passage 66. Yes. An exhaust gas heat exchanger 67 is provided on the exhaust passage 66. The exhaust gas heat exchanger 67 is provided on the second cooling water circulation path 68. A second boiler 65 as a second heat exchanger is provided on the second cooling water circulation path 68, and the second boiler 65 is connected to the outlet of the first boiler 64 via the connection flow path 63. ing.

In the exhaust gas heat exchanger 67, heat exchange is performed between the exhaust gas and the cooling water in the second cooling water circulation path 68. Then, the cooling water heat-exchanged with the waste heat of the exhaust gas is heated and circulated through the second cooling water circulation path 68. The cooling water circulating in the second cooling water circulation path 68 is a heat source for the second boiler 65. In the cooling water that is the heat source in the first boiler 64 and the cooling water that is the heat source in the second boiler 65, the temperature of the cooling water in the second boiler 65 is slightly higher, and the temperature difference is small.

A suction port (not shown) that is the inlet of the expander 20 is connected to the outlet of the second boiler 65 via the second flow path 14. A condenser 30 is connected to the expander 20 via a flow path 15, and a pump 40 is connected to the condenser 30 via a flow path 16.

In the refrigerant circulation direction in the refrigerant circulation circuit 12, a restrictor 69 is provided as a restricting portion on the connection flow path 63 that is downstream from the first boiler 64 and upstream from the second boiler 65. The aperture 69 can be adjusted in opening. The refrigerant introduced into the throttle 69 is expanded and depressurized, and then introduced into the second boiler 65 through the connection channel 63.

Further, a temperature sensor 70 is provided on the flow path 14 located downstream from the second boiler 65 and upstream from the expander 20 in the refrigerant circulation direction in the refrigerant circulation circuit 12. The temperature sensor 70 is the temperature of the refrigerant immediately after passing through the second boiler 65, and detects the suction temperature at the inlet of the expander 20. The temperature sensor 70 is signal-connected to the control unit 73. Then, the control unit 73 adjusts the opening degree of the diaphragm 69 based on the temperature information from the temperature sensor 70.

In order to prevent the heat quantity of the refrigerant at the outlet of the expander 20 from exceeding the heat dissipation capacity of the condenser 30, the control unit 73 opens the throttle 69 with respect to the temperature information (suction temperature of the expander 20). A map in which the degrees are associated is stored in advance.

FIG. 3 (b) shows changes in the enthalpy and pressure of the refrigerant in the Rankine cycle apparatus without the throttle 69, and FIG. 3 (c) shows the enthalpy and pressure of the refrigerant in the Rankine cycle apparatus 10 of the third embodiment. Showing change. 3 (b) and 3 (c), the horizontal axis represents enthalpy, the vertical axis represents pressure, the curve E represents a saturated liquid line and a saturated vapor line, and the curve T represents cooling water. Represents the isotherm. Note that enthalpy is the amount of internal pressure added to the product of refrigerant pressure and volume, and the amount of heat entering and exiting the refrigerant is equal to the amount of change in enthalpy under constant pressure conditions. The quantity indicates the amount of change in the heat quantity of the refrigerant.

3B, a two-dot chain line J1 from the intersection point Q1 to the intersection point Q2 represents a condensation stroke by the condenser 30, and a two-dot chain line J2 from the intersection point Q2 to the intersection point Q3 represents a pumping stroke by the pump 40. A two-dot chain line J3 from the intersection point Q3 to the intersection point Q4 is a first heating stroke by the first boiler 64, and a two-dot chain line J4 from the intersection point Q4 to the intersection point Q5 is a second heating stroke by the second boiler 65, the intersection point from the intersection point Q5. A two-dot chain line J5 up to Q1 represents an expansion stroke by the expander 20. The two-dot chain lines J1 to J5 indicate changes in the enthalpy and pressure of the refrigerant in the Rankine cycle device without the throttle 69.

3C, a solid line D1 from the intersection R1 to the intersection R2 represents a condensation stroke by the condenser 30, and a solid line D2 from the intersection R2 to the intersection R3 represents a pressure feed stroke by the pump 40. A solid line D3 from the intersection R3 to the intersection R4 is a first heating stroke by the first boiler 64, a solid line D4 from the intersection R4 to the intersection R5 is a decompression stroke by the throttle 69, and a solid line D5 from the intersection R5 to the intersection R6 is a second line D5. The second heating stroke by the boiler 65, the solid line D6 from the intersection R6 to the intersection R1 represents the expansion stroke by the expander 20. The solid lines D1 to D6 indicate changes in the enthalpy and pressure of the refrigerant in the Rankine cycle device 10 according to the third embodiment.

Note that in the Rankine cycle device that does not include the throttle 69, the circuit components other than the throttle 69 are the same as the circuit components of the Rankine cycle device 10 of the third embodiment. These circuit constituent members will be described using the same member numbers as the circuit constituent members in the Rankine cycle apparatus 10 of the third embodiment.

In the Rankine cycle device not provided with the throttle 69, the expansion of the pump 40 and the pump 40 is performed such that the refrigerant pressure P1 at the outlet of the pump 40 is lower than the saturation pressure Psat (t11) at t11 which is the refrigerant temperature in the first boiler 64. The capacity ratio of the machine 20 is preset (Formula 1).

P1 <Psat (t11) ... Formula 1
Further, in the Rankine cycle device in which the throttle 69 is not provided, the refrigerant receives heat from the first boiler 64 by Δh31 and also receives heat from the second boiler 65 by Δh32. Since the refrigerant can receive heat up to a position where the curve T (isothermal line) and the pressure P1 intersect at the maximum, the amount of heat received (heat absorption amount) may be excessive.

In the Rankine cycle device 10 of the third embodiment, the temperature of the refrigerant immediately after passing through the first boiler 64 is t21, and the pressure of the refrigerant is P2. Further, as shown in FIG. 3C, the enthalpy increase amount (endothermic amount: length of the solid line D3) in the first boiler 64 is Δh41, and the enthalpy increase amount (endothermic amount: solid line D5) in the second boiler 65. Is set to Δh42.

Now, in the Rankine cycle device 10 of the third embodiment, when the control unit 73 determines that the endothermic amount is excessive based on the temperature information detected by the temperature sensor 70, the control unit 73 decreases the opening of the throttle 69. That is, the temperature of the refrigerant after passing through the second boiler 65 is high (a large amount of heat absorption), and after the mechanical energy is taken out by the expander 20, the heat quantity of the refrigerant at the outlet of the expander 20 becomes the heat dissipation of the condenser 30. If the control unit 73 determines that the capacity is exceeded, the control unit 73 reduces the opening of the diaphragm 69. At this time, since the suction volume of the expander 20 and the refrigerant flow rate do not change, the refrigerant pressure P1 in the second boiler 65 does not change. Therefore, when the opening degree of the throttle 69 is reduced, the pressure of the refrigerant upstream of the throttle 69 increases to P2. That is, the opening degree of the throttle 69 is adjusted by the first boiler 64 so that the refrigerant pressure P2 is higher than the saturation pressure Psat (t1) at the temperature t1 of the cooling water (waste heat medium) (Equation 2). .

P2> Psat (t1) ... Formula 2
When the opening degree of the throttle 69 is adjusted as described above, the maximum amount of heat (increased enthalpy) Δh41 that can be received by the refrigerant in the first boiler 64 is equal to the refrigerant pressure P2 and the curve T in the first boiler 64. Limited to the intersection. Therefore, in the Rankine cycle device 10 of the third embodiment, the enthalpy increase amount Δh41 in the first boiler 64 is smaller than the enthalpy increase amount Δh31 in the first boiler 64 in the Rankine cycle device without the throttle 69 (formula 3).

Δh41 <Δh31 ... Formula 3
Thereafter, the refrigerant is depressurized by the throttle 69 and receives heat by the second boiler 65 by an enthalpy increase amount Δh42. Since the enthalpy increase amount Δh42 in the second boiler 65 is substantially the same as the enthalpy increase amount Δh32 in the second boiler 65 in the Rankine cycle device without the throttle 69, the amount of heat received in the first boiler 64 is (increase amount). The amount of heat received by the Rankine cycle apparatus 10 provided with the throttle 69 is decreased by the amount of decrease (Equation 4).

Δh41 + Δh42 <Δh31 + Δh32 (Formula 4)
As a result, the amount of heat of the refrigerant immediately after passing through the second boiler 65 is less than the amount of heat of the refrigerant immediately after passing through the second boiler 65 in the Rankine cycle device without the throttle 69.

According to the third embodiment, in addition to the same advantages as (2) and (3) of the first embodiment, the following advantages can be obtained.

(5) The refrigerant circulation circuit 12 of the Rankine cycle device 10 is provided with the first boiler 64 and the second boiler 65, and is throttled 69 downstream from the first boiler 64 and upstream from the second boiler 65 in the refrigerant circulation direction. Was provided. The amount of heat received by the refrigerant in the first boiler 64 intersects with the pressure P2 of the refrigerant in the first boiler 64 and the isotherm T by increasing the refrigerant pressure P2 in the first boiler 64 by the throttle 69. It is limited to the position (until it becomes equal to the temperature t1 of the cooling water). Therefore, in the Rankine cycle device 10, the enthalpy increase amount Δh41 in the first boiler 64 is smaller than the enthalpy increase amount Δh31 in the first boiler 64 in the Rankine cycle device without the throttle 69, and the expander 20 is discharged from the pump 40 outlet. The amount of heat received by the refrigerant can be limited up to the entrance (first boiler 64). As a result, it is possible to prevent the amount of heat of the refrigerant at the outlet of the expander 20 from exceeding the heat dissipation capability of the condenser 30. Therefore, it is possible to prevent the refrigerant from being liquefied by the condenser 30 and supplied to the pump 40 in the gas-liquid mixed state, to prevent the pump 40 from generating cavitation, and to pump the refrigerant by the pump 40. A decrease can be prevented. In order to prevent the occurrence of cavitation, it is not necessary to increase the size of the condenser 30 to increase the heat dissipation capability, and therefore, an increase in cost due to an increase in the size of the condenser 30 does not occur. In addition, by reducing the amount of heat of the refrigerant immediately after passing through the first boiler 64, the intake temperature at the inlet of the expander 20 can be prevented from becoming too high, and the cost of adopting the heat resistant design of the expander 20 There is no increase.

Note that the first to third embodiments may be modified as follows.

In the first embodiment, the waste heat medium is embodied in the cooling water to which the waste heat from the waste heat source 51 is transmitted, and is embodied in the cooling medium circulation circuit 52 in which the cooling water circulates in the waste heat path. Not exclusively. As shown in FIG. 4, in the Rankine cycle device 10 of the third embodiment, the waste heat path is embodied in the exhaust passage 66 connected to the engine 58, and the waste heat medium is embodied in the exhaust gas flowing in the exhaust passage 66. To do. Further, a second boiler 65 is provided on the exhaust passage 66, and the second boiler 65 enables heat exchange between the exhaust passage 66 and the connection flow path 63. That is, heat exchange is possible between the exhaust gas flowing through the exhaust passage 66 and the refrigerant flowing through the connection flow path 63, and waste heat from the engine 58 is transferred to the refrigerant via the exhaust gas to exchange heat. A muffler 74 is provided in the exhaust passage 66.

Also, in the exhaust gas exhaust direction in the exhaust passage 66, the upstream and downstream sides of the second boiler 65 are connected by a heat exchanger bypass passage 75 as a restricting portion. The heat exchanger bypass passage 75 allows the exhaust gas to bypass the second boiler 65 when the exhaust gas flows through the exhaust passage 66. On the heat exchanger bypass passage 75, an on-off valve 76 is provided as a limiting portion. And based on the temperature information from the temperature sensor 70, the control part 73 adjusts the opening / closing of the on-off valve 76, and adjusts the opening degree of the heat exchanger bypass passage 75. FIG.

As the opening degree of the opening / closing valve 76 becomes smaller, the flow rate of the exhaust gas flowing through the second boiler 65 increases, so the amount of heat that can be received by the refrigerant in the second boiler 65 increases, and the opening degree of the opening / closing valve 76 becomes larger. As the flow rate increases, the flow rate of the exhaust gas flowing through the second boiler 65 decreases, and the amount of heat that the refrigerant can receive by the second boiler 65 decreases. Then, the opening degree of the on-off valve 76 is controlled by the control unit 73 so that the heat quantity of the refrigerant at the outlet of the expander 20 does not exceed the heat dissipation capacity in the condenser 30 with respect to the temperature information.

In the first to third embodiments, instead of the temperature sensor S, the superheat degree sensor 57, and the temperature sensor 70, a supercooling degree sensor is provided at the inlet of the pump 40. The degree of supercooling may be detected as temperature information, and the opening degree of the on-off

valves

54 and 56 and the throttle 69 may be adjusted based on the degree of supercooling.

Specifically, as shown in FIG. 5, in the first embodiment, the temperature sensor S is deleted, and a supercooling degree sensor 71 is provided at a position that becomes the inlet (suction side) of the pump 40 in the refrigerant circulation circuit 12. The supercooling degree sensor 71 is provided and connected to the control unit 73. If the heat absorption amount in the boiler 50 becomes excessive, the degree of supercooling at the inlet of the pump 40 detected by the supercooling degree sensor 71 is less than a predetermined value (for example, 5 ° C. or less, usually 5 to 15 ° C.), the control unit 73 adjusts the opening degree of the on-off valve 54. As a result, the amount of heat received by the refrigerant between the outlet of the pump 40 and the inlet of the expander 20 is limited.

In the first embodiment, a superheat degree sensor 57 may be provided instead of the temperature sensor S, and the superheat degree detected by the superheat degree sensor 57 may be used as temperature information.

In the second embodiment, a temperature sensor S may be provided instead of the superheat degree sensor 57, and the temperature detected by the temperature sensor S may be used as temperature information.

In the third embodiment, the opening degree of the diaphragm 69 is adjusted by the control of the control unit 73, but instead of the diaphragm 69, a limiter that can be controlled internally may be used.

The Rankine cycle device 10 may be used for a solar power generation system, a power generation system in a factory, and the like in addition to the vehicle.

The working fluid may be changed to water or the like instead of the refrigerant. Further, the waste heat medium may be a gas instead of a liquid such as cooling water.

Although the pump 40 is directly connected to an external drive source through a pulley, the pump 40 may be driven by a motor. In this case, the motor cannot be controlled by the inverter.

The pump 40 and the expander 20 may be one in which the pump 40 and the shaft of the expander 20 are directly connected. In this case, the pump 40 is driven by the external drive source Fb. When the expander 20 starts to output mechanical energy, the pump 40 is driven using the output mechanical energy as a power source.

In the second embodiment, a temperature-sensitive expansion valve is used instead of the superheat degree sensor 57, and a change in the superheat degree of the refrigerant that has exited the boiler 50 is detected by a temperature-sensitive cylinder, and flows into the boiler 50 according to the detection result. The refrigerant to be adjusted may be adjusted. And the temperature-sensitive expansion valve keeps the degree of superheating of the refrigerant constant, and limits the amount of heat absorption so that the heat quantity of the refrigerant at the outlet of the expander 20 does not exceed the heat dissipation capability of the condenser 30. Also good.

Fb: external drive source, 10: Rankine cycle device, 12: refrigerant circulation circuit as working fluid circuit, 20: expander, 30 ... condenser, 40 ... pump, 50 ... boiler as heat exchanger, 51 ... waste heat source 52 ... Cooling medium circulation circuit as a waste heat path, 53 ... Heat exchanger bypass passage as a restriction section, 54 ... Open / close valve as a restriction section, 55 ... Boiler bypass passage as a heat exchanger bypass passage of the restriction section, 56: Open / close valve as a limiting unit, 58 ... Engine as a waste heat source, 64 ... First boiler as a first heat exchanger, 65 ... Second boiler as a second heat exchanger, 66 ... As a waste heat path Exhaust passage, 69... Restriction as restricting portion, 75... Heat exchanger bypass passage as restricting portion, 76.

Claims

Rankine cycle device,
Waste heat source,
A working fluid circuit, the working fluid circuit comprising:
A pump for pumping the working fluid;
A heat exchanger for exchanging heat between the working fluid pumped from the pump and waste heat from the waste heat source;
An expander that expands the working fluid heat-exchanged by the heat exchanger and outputs mechanical energy;
A condenser for condensing the working fluid expanded by the expander;
The working fluid circuit configured by sequentially connecting
Limiting the amount of heat received by the working fluid from the outlet of the pump to the inlet of the expander on the working fluid circuit based on temperature information sensed at the pump inlet or the expander inlet A restriction section to
A Rankine cycle device comprising:
The Rankine cycle device further includes a waste heat path through which a waste heat medium flows,
Waste heat from the waste heat source is transferred to the waste heat medium, and in the heat exchanger, heat is exchanged between the waste heat medium and the working fluid,
The Rankine cycle apparatus according to claim 1, wherein the restriction unit is a heat exchanger bypass passage provided so that at least a part of the waste heat medium flowing through the waste heat path bypasses the heat exchanger.
The Rankine cycle apparatus according to claim 2, wherein the waste heat path is a cooling medium circulation circuit that circulates a cooling medium that cools the waste heat source, and the waste heat medium is the cooling medium.
2. The Rankine cycle device according to claim 1, wherein the restriction unit is a heat exchanger bypass passage provided so that at least a part of the working fluid flowing in the working fluid circuit bypasses the heat exchanger.
Based on the intake temperature of the working fluid at the inlet of the expander as the temperature information, the degree of superheat at the inlet of the expander, or the degree of supercooling at the inlet of the pump, the heat exchanger bypass passage The Rankine cycle device according to any one of claims 2 to 4, wherein the opening degree is adjusted.
The heat exchanger includes: a first heat exchanger that exchanges heat with the working fluid pumped from the pump; and a second heat exchanger that exchanges heat with the working fluid heat-exchanged in the first heat exchanger. Including
2. The restriction is an aperture-adjustable throttle provided in a portion of the working fluid circuit that is downstream from the first heat exchanger and upstream from the second heat exchanger. Rankine cycle equipment.
The throttle opening is adjusted so that the pressure of the working fluid that has passed through the first heat exchanger is higher than the saturation pressure of the working fluid at the waste heat medium temperature of the first heat exchanger. 6. Rankine cycle device according to 6.
The opening degree of the throttle is adjusted based on the intake temperature of the working fluid at the inlet of the expander, the degree of superheat at the inlet of the expander, or the degree of supercooling at the inlet of the pump as the temperature information The Rankine cycle apparatus according to claim 6 or 7.
The Rankine cycle device according to any one of claims 1 to 8, wherein the pump is driven in accordance with the rotational speed of an external drive source.