JP2011012644A - Heat engine cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new heat engine cycle device which increases net thermal efficiency, reduces a size and is enabled in flexible layout design.SOLUTION: A heat engine cycle device 10 is composed of heat exchangers HX1, HX2 for accommodating working fluids 19, a connection pipe 18, a control valve 11, an expander 12, introduction pipes 16, 17 for guiding heat source fluids from a heat source 1 or a cooling source 2 to the heat exchangers HX1, HX2, a flow path switching valve 14 for switching the heat source fluid guided to the introduction pipes 16, 17, and a control device 15 for monitoring a pressure difference between the working fluids 19 before and after the expander 12 circulating the working fluids 19 by opening the control valve 11 when the pressure difference reaches a set upper limit value and switching the heat source fluids guided to the introduction pipes 16, 17 by switching the flow path switching valve 14 when the pressure difference reaches the set lower limit value after the opening.

Description

  The present invention relates to a heat engine cycle apparatus that performs power recovery / power generation from a low-temperature heat source, and more particularly, to a temperature difference heat engine cycle apparatus that operates using a temperature difference between a high-temperature heat source and a low-temperature heat source.

One of the countermeasures for energy and environmental problems such as depletion of fossil fuels and global warming is the effective use of renewable energy, and the use of sunlight, wind power, hydropower, biomass, etc. is spreading. In addition, although it is generated in large quantities, it is expected to become a renewable energy even for low-temperature heat sources with low temperature and high dispersibility (for example, factory exhaust heat, exhaust heat from small gas turbines and automobile engines, solar heat, etc.). For example, if 5% of the annual factory exhaust heat in Japan (Japan) is converted into power or electric power, a reduction in CO ₂ emissions of approximately 1.25 million tons per year is expected when converted to carbon.

  As a heat engine cycle device that performs power recovery / power generation from a low-temperature heat source, there is a device that uses a Rankine cycle (see, for example, Patent Document 1). The Rankine cycle device is a basic steam cycle device and is typically composed of a feed pump (working fluid pump), an evaporator, a turbine / expander, a condenser, and a working fluid. The working fluid of the low-pressure liquid is adiabatically compressed by a supply pump to become high-pressure liquid, is heated at an equal pressure by an evaporator to become high-pressure steam, and performs mechanical work when adiabatically expanding by a turbine. After that, it becomes low-pressure steam and is cooled at the same pressure by a condenser to return to a low-pressure saturated liquid. The net thermal efficiency of the Rankine cycle system is a value obtained by subtracting the pump power from the turbine output and dividing by the heating amount.

  In a small, low temperature difference Rankine cycle device, when the heat source temperature, that is, the amount of heat fluctuates, the discharge pressure and flow rate of the working fluid pump change according to the fluctuation, so there is a working fluid pump that maintains high efficiency in the fluctuation range. Necessary. However, at present, it is difficult to select / design such a pump, and the use of a working fluid pump having high pump power to some extent leads to a decrease in net thermal efficiency. Also, it is necessary to secure an effective suction head to prevent cavitation from occurring at the pump inlet, which is an obstacle to downsizing of the apparatus and flexible layout design.

  In the Rankine cycle device of Patent Document 1, the working fluid in the gas phase is mixed with the working fluid in the liquid phase on the inlet side of the fluid pump, so that only the density of the working fluid is reduced without substantially changing the enthalpy. The density of the working fluid on the inlet side of the expander is also reduced to enable operation under efficient conditions. However, like a normal Rankine cycle device, a working fluid pump is required. However, the above-described problems (particularly the latter miniaturization and design flexibility) cannot be solved.

  Patent Document 2 discloses a high heat source by providing an evaporator, a gas-liquid separator, an absorber, and a regenerator in order to eliminate the disadvantages of the conventional Rankine cycle, such as a decrease in thermal efficiency and an increase in power generation cost. Although the temperature difference power generation device which reduced the motive power for pumping up a low heat source is disclosed, a working fluid pump is required like patent document 1, and the above-mentioned subject cannot be solved.

  Patent Document 3 discloses a power generator that recovers exhaust heat without requiring a working fluid pump. However, in the exhaust heat recovery power generation device of Patent Document 3, since the working fluid is transported from the airtight tank to the evaporation pipe by the position head, it is an unrealistic height that is unacceptable in terms of downsizing and device design. While the difference is necessary, it is considered that it is very difficult to actually operate the power generation device based on the experience of the present inventor.

JP 2009-103029 A Japanese Patent Laid-Open No. 7-91361 JP 54-148944 A

  An object of the present invention is to solve this problem and to provide a new heat engine cycle device that can increase the net thermal efficiency and can be downsized and flexible in layout design.

  The present inventor removed the working fluid pump, which was the main cause of the above problem, from the configuration of the conventional Rankine cycle device after intensive study, and the role of the heat exchanger as an evaporator or a condenser only by operating the valve. It has been found that if it can be switched alternately and intermittently, a new heat engine cycle device (power recovery / power generation device) similar to the Rankine cycle can be constructed, and the present invention has been completed.

The heat engine cycle device of the present invention includes, for example, first and second heat exchangers that contain a working fluid,
A connecting pipe that is connected to the first and second heat exchangers and that circulates the working fluid;
A control valve provided on the connecting pipe and controlling the flow of the working fluid by opening and closing the valve;
An expander that is provided on the connecting pipe and operates by circulation of the working fluid;
First and second introduction pipes for guiding a heat source fluid from a heat source or a cooling source to the first and second heat exchangers;
A flow path switching valve for switching the heat source fluid guided to the first and second introduction pipes;
When the pressure difference of the working fluid before and after the expander is monitored and the set upper limit value is reached, the control valve is opened to flow the working fluid, and after opening, the pressure difference reaches the set lower limit value And a control device for switching the heat source fluid guided to the first and second introduction pipes by switching the flow path switching valve.

  According to the heat engine cycle device of the present invention, the heat engine cycle can be operated without using a working fluid pump, which is essential in the conventional Rankine cycle device and the like and has been the main factor of the decrease in the net heat efficiency. Can be improved.

  Moreover, since the working fluid pump is not used, the layout design of the apparatus can be given flexibility and the sealing property of the working fluid can be ensured.

  In addition, if a fluid whose boiling point is lower than the boiling point of water and suitable for the temperature range of the heat source is selected as the working fluid, the heat source (factory exhaust heat, automobile exhaust heat, etc.) having a low temperature and high dispersibility can be used. The heat engine cycle device can be optimally applied, and the net thermal efficiency can be further improved.

It is the figure which showed the apparatus structure of the heat engine cycle apparatus which concerns on Example 1 of this invention. The Ts diagram and ph diagram in the heat engine cycle of the present invention are shown. It is a flowchart which shows the control method which the control apparatus 15 of this invention performs. 3 is a diagram illustrating an example of a change over time in turbine output while the control device 15 opens the control valve 11. FIG. It is the figure which showed the apparatus structure of the heat engine cycle apparatus which concerns on Example 2 of this invention. It is the figure which showed the apparatus structure of the heat engine cycle apparatus which concerns on Example 3 of this invention. It is the figure which showed the apparatus structure of the heat engine cycle apparatus which concerns on Example 4 of this invention. It is the figure which showed the structure of the heat engine cycle multiple connection system which concerns on Example 5 of this invention. It is the figure which showed the turbine output in each cycle apparatus of Example 5, and the generated electric power of the whole system which overlap | superposed these. It is the figure which showed the apparatus structure of the heat engine cycle multiple connection system which concerns on Example 6 of this invention. It is the figure which showed the apparatus structure of the heat engine cycle multiple connection system which concerns on Example 7 of this invention. It is the figure which showed the outline of the experimental apparatus for verifying the heat engine cycle of this invention. It is the figure which showed the experimental result (time change of a pressure and enthalpy) of the verification experiment of FIG. It is the figure which showed the experimental result (Pressure difference, enthalpy difference, mass flow rate, and time change of turbine output) of the verification experiment of FIG.

  Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. In addition, this invention is not limited to these Examples at all.

  FIG. 1 shows a heat engine cycle apparatus 10 according to a first embodiment of the present invention. The heat engine cycle device 10 includes a first heat exchanger HX1, a second heat exchanger HX2, a control valve 11, a reciprocating flow expander 12, a flow path switching valve 14, a control device 15, a first The inlet pipe 16, the second inlet pipe 17, and the connecting pipe 18 are configured.

  Since the first and second heat exchangers HX1 and HX2 can store the working fluid 19 and are connected to each other by the connecting pipe 18, the working fluid 19 includes the first heat exchanger HX1 and the second heat exchanger HX2. It is possible to go between (distribution). A control valve 11 whose opening and closing is controlled by the control device 15 and a reciprocating flow expander 12 driven by the flow of the working fluid 19 opened by the control valve 11 are provided on the connecting pipe 18. Power can be recovered by the operation of the reciprocating expander 12. Further, a generator 13 may be connected to the reciprocating expander 12, which makes it possible to convert the recovered power into electric power.

  The first introduction pipe 16 is piped so as to circulate inside the first heat exchanger HX1, and the fluid of the heat source 1 or the cooling source 2 (hereinafter also referred to as “heat source fluid”) is the first heat exchanger 1. And the working fluid 19 is heated or cooled. Similarly, the second introduction pipe 17 is piped so as to circulate inside the second heat exchanger HX2, and guides the heat source fluid of the heat source 1 or the cooling source 2 into the second heat exchanger 2, The working fluid 19 is heated or cooled.

  Examples of the heat source fluid include vaporized exhaust heat gas, liquid warm water, and cooling water. Since these heat source fluids have different physical property values (for example, specific heat and thermal conductivity), they are applied to the first and second introduction pipes 16 and 17 and the first and second heat exchangers HX1 and HX2 per unit flow rate. The amount of heat is different. Therefore, the first and second introduction pipes 16 and 17 and the first and second heat exchangers HX1 can be flexibly and appropriately designed (for example, downsized) by appropriately selecting the physical properties and flow rate of the heat source fluid. .

Next, the operation principle of the present invention will be described with reference to the apparatus configuration of the first embodiment.
(A) Equal volume heating First, the control valve 11 is set in a closed state by the control device 15, and the high-temperature fluid of the heat source 1 flows through the first heat exchanger HX1, while the cooling source is supplied to the second heat exchanger HX2. 2 cold fluid flows. That is, the first heat exchanger HX1 functions as an evaporator, and the second heat exchanger HX2 functions as a condenser. At this time, as an initial state, the first heat exchanger HX1 is filled with a larger amount of the working fluid 19 than the second heat exchanger HX2, or the working fluid 19 is sealed only in the first heat exchanger HX1. It shall be. By the equal volume heating, the working fluid 19 in the first heat exchanger HX1 becomes a high temperature and high pressure state. (On the other hand, when the working fluid 19 is also present in the second heat exchanger HX2, the working fluid 19 in the second heat exchanger HX2 is in a low temperature and low pressure state.)

(B) Isobaric heating When the pressure of the working fluid 19 in the first and second heat exchangers HX1 and HX2 reaches the set pressure set by the control device 15, the control valve 11 is opened by the control device 15. . The high-temperature and high-pressure working fluid 19 in the first heat exchanger HX1 is heated under substantially equal pressure to become steam (here, when the working fluid 19 is other than water, it is also called steam), and the first heat exchanger HX1. From the first through the connecting pipe 18 to the second heat exchanger HX2 (see the right arrow in FIG. 1).

(C) Adiabatic expansion At this time, the high-temperature and high-pressure working fluid 19 performs mechanical work by adiabatic expansion in a reciprocating flow expander (herein, the expander is also referred to as “turbine”) 12. Here, “adiabatic expansion” is ideal expansion without heat loss, and actually “expansion” with heat loss. For the convenience of explanation for comparison with the basic principle of Rankine cycle, “adiabatic expansion” is used. Reciprocating flow theory turbine output _{L T} of the expander 12 is multiplied by the difference between the reciprocating flow expander 12 enthalpy of about _h 1, _{h 2} in the mass flow rate m of the working fluid 19 expression at this time _(L T = m × (h _1- h ₂ )). However, unlike the conventional Rankine cycle turbine output L _T changes with time.

(D) Isobaric cooling The steam (working fluid) 19 that has passed through the reciprocating flow expander 12 becomes a low temperature and a low pressure, and is cooled under substantially equal pressure by the second heat exchanger HX2 to become a saturated liquid (or a gas-liquid two-phase state). . According to the operating principle of the present invention, the working fluid 19 in the first heat exchanger HX1 moves to the second heat exchanger HX2 after opening the control valve 11 (that is, the working fluid 19 before and after the reciprocating flow expander 12). during the pressure difference of the until) a zero or substantially zero, it is possible to obtain a turbine output L _T.

(E) Equal volume cooling Upon completion of the above process, most of the working fluid 19 is in a state of being accommodated in the second heat exchanger HX2. The control device 15 closes the control valve 11 opened to allow the working fluid 19 to pass, and switches the position of the flow path switching valve 14. During the time from when the control valve 11 is closed until the position of the flow path switching valve 14 is switched, the working fluid 19 in the second heat exchanger HX2 is cooled in the same volume. In actual operation, this time is assumed to end in a shorter time than other processes, and therefore, the state point is not clearly shown on the diagram of FIG.

  In this way, after the equal pressure cooling in the step (d) is finished, the control valve 11 is closed, and after the equal volume cooling in the step (e), the position of the flow path switching valve 14 is switched. While the low-temperature heat source fluid is guided to the first heat exchanger HX1), the high-temperature heat source fluid is guided to the second introduction pipe 17 (and hence the second heat exchanger HX2), and one cycle of the present invention is completed. To do. In the subsequent cycles, the first heat exchanger HX1 functioning as an evaporator and the second heat exchanger HX2 functioning as a condenser function as a condenser and an evaporator, respectively. That is, in the second heat exchanger HX2, the process returns to the process (a) equal volume heating process again, and the cycle of the present invention is started. Thus, in the present invention, by switching the heat exchanger function, the operation of pushing the working fluid by the supply pump from the low-pressure condenser to the high-pressure evaporator can be omitted in the Rankine cycle of the prior art.

  In the second cycle, the pressure of the working fluid 19 in the first and second heat exchangers HX1 and HX2 is set to the set pressure set by the control device 15 as in the adiabatic expansion process of the process (c). When it reaches, the control valve 11 is opened by the control device 15. The high-temperature and high-pressure working fluid 19 in the second heat exchanger HX2 is heated under equal pressure to become steam, and adiabatically expands in the reciprocating flow expander 12 to perform mechanical work. However, the working fluid 19 flows from the second heat exchanger HX2 toward the first heat exchanger HX1 opposite to the previous cycle (see the left arrow in FIG. 1).

  The heat engine cycle device 10 according to the first embodiment operates under the operating principle as described above. Paying attention to the changing process experienced by the working fluid 19, the cycle of the present invention includes (a) equal volume heating, (b) isobaric heating, (c) adiabatic expansion, (d) isobaric cooling, and (e) isobaric cooling. It is done in order. FIG. 2 shows the cycle of the present invention with a TS diagram (T: temperature, s: entropy) and a ph diagram (p: pressure, h: enthalpy). In these diagrams, when the cycle of the present invention is operated, the state changes in the order of point A → B point → C point → D point → (E point) → A point (however, in FIG. 2, (e ) Equal volume cooling and point E are omitted). Here, the difference in enthalpy h from point C to point D in FIG. 2 corresponds to the mechanical work performed by the reciprocating flow expander 12.

  2A and 2B, a diagram indicated by a broken line (A ′ point → Bp ′ point → B ′ point → C ′ point → D ′ point → (E ′ point) → A ′ point). Shows a conventional Rankine cycle (however, in FIG. 2, (e) equal volume cooling and E ′ point are omitted). Compared with this conventional cycle, it can be seen that the cycle of the present invention without a working fluid pump draws a diagram similar to that of the conventional cycle and performs equivalent mechanical work. Note that the state of the conventional cycle is changed from the point A ′ to the point Bp ′ to the point B ′ because the working fluid is once increased to the point B ′ by the working fluid pump essential for the conventional cycle. On the other hand, since the working fluid pump is unnecessary in the cycle of the present invention, the state shifts from point A to point B. The power of the working fluid pump consumed in the conventional cycle is replaced with the power required for controlling the flow path switching valve 14 that switches the flow of the heat source fluid in the cycle of the present invention.

  Next, the main elements constituting the heat engine cycle device 10 of the present invention will be described in detail. First, the flow path switching valve 14 is not limited to the four-way valve shown in FIG. 1, and for example, a three-way valve may be used. In addition, when using a three-way valve, it is necessary to prepare at least two, and in the case of a four-way valve, it is possible to perform flow path switching with only one.

  Further, the control valve 11 shown in FIG. 1 is provided on the connecting pipe 18 between the first heat exchanger HX1 and the reciprocating flow expander 12, but the present invention is not limited to this. You may provide on the connection pipe 18 between 2nd heat exchanger HX2. Further, two control valves 11 may be prepared and arranged on the connecting pipes 18 before and after the reciprocating flow expander 12, respectively. When a plurality of control valves 11 are arranged, there is an advantage that work handling (handling) is facilitated when the reciprocating flow expander 12 is mounted, repaired, or replaced.

  Examples of the reciprocating expander 12 include a Wells turbine, a rectifying impulse turbine, and a screw turbine that are used for wave power generation. If such a reciprocating flow expander 12 is used, power can be recovered with a single expander and the working fluid 19 can rotate only in the same direction regardless of the forward or backward flow of the working fluid 19. Therefore, the entire apparatus 10 becomes very compact.

  In addition, when the heat engine cycle device 10 of the present invention is intended for power generation, it is also possible to apply an expander 12 that can rotate forward and backward according to the flow direction of the working fluid 19 instead of the reciprocating flow expander 12. is there. That is, even if the rotation direction of the expander 12 is reversed, power can be generated or stored by adding an inverter and a regenerative converter (in the case of alternating current) or a reversible chopper (in the case of direct current) to the output side from the generator 13. It becomes possible. The forward / reverse rotation expander 12 preferably includes a rotary vane type or gear type expander, but is not limited to this, and has a structure such as an internal flow path mechanism so that it can rotate in the forward / reverse direction. If added, it can also be applied to expanders such as screw type, scroll type, axial piston type, disk turbine type, and radial turbine type.

  Although only one connecting pipe 18 is shown in FIG. 1, a plurality of (for example, two) connecting pipes 18 may be connected to the reciprocating flow expander (forward / reverse rotating expander) 12. In this case, each connecting pipe 18 is provided with a control valve 11. For example, when two connecting pipes 18 are connected to the expander 12, the working fluid 19 flows through the one connecting pipe 18 in the right direction (that is, the direction from the first heat exchanger HX1 to the second heat exchanger HX2). It is possible to use the other connecting pipe 18 when flowing in the left direction (that is, the direction from the second heat exchanger HX2 to the first heat exchanger HX1). By adopting such a configuration, it is possible to adapt to various turbine piping and inlet / outlet structures.

  In addition, the heat engine cycle device 10 of the present invention does not require a working fluid pump in which the working fluid easily leaks from the periphery of the shaft unlike the conventional device, and therefore, the hermeticity of the working fluid 19 is significantly higher than that of the conventional Rankine cycle device. There is also an advantage that can be improved. That is, it is not necessary to limit the working fluid 19 applicable to the present invention from the viewpoint of sealing.

  In addition, when applying the heat engine cycle apparatus 10 of the present invention to a heat source having a low temperature range (for example, 100 to 200 ° C.), the working fluid 19 preferably has a boiling point equal to or lower than that of water. The following are shown in Table 1. It should be noted that each working fluid 19 shown in Table 1 below has a different temperature range suitable for operation. (Note that the temperature range shown in Table 1 is an approximate guide, and may vary depending on pressure conditions, etc.) Therefore, the following table is used according to the temperature range of the heat source 1 to which the heat engine cycle device 10 of the present invention is applied. It is preferable to select the optimum working fluid 19 from the above. By doing so, the net thermal efficiency of the heat engine cycle device 10 of the present invention can be further improved.

Next, the control device 15 of the present invention will be described with reference to FIGS. The control device 15 monitors the pressures p ₁ and p ₂ of the connecting pipe 18 before and after the reciprocating expander 12 during the operation of the cycle of the present invention (see FIG. 1). FIG. 3 is a flowchart showing a control method performed by the control device 15. First, the control device 15 closes the control valve 11 (step S1). Then, the flow path switching valve 14 is operated, and the fluid of the heat source 1 or the cooling source 2 is guided to the first and second introduction pipes 16 and 17 to heat or cool the first and second heat exchangers HX1 and HX2 (step). S2). Then, the working fluid 19 accommodated in the connecting pipe 18 connected to the first and second heat exchangers HX1 and HX2 is heated on one side of the reciprocating flow expander 12 and cooled on the other side. The pressure difference Δp between p ₁ and the pressure p ₂ increases. When the pressure difference Δp reaches a pressure difference (upper limit pressure difference) Δp _SET set in advance in the control device 15, the control device 15 opens the control valve 11 (step S3). As a result, the reciprocating flow expander 12 (and the generator 13) operates, so that power / electric power can be recovered.

Figure 4 shows an example of a change with time of the turbine output L _T between opening the control valve 11. Figure 4 immediately after the control valve 11 open than it is large turbine output L _T obtained gradually output decreases (i.e., the pressure p ₁ and pressure p ₂ the same). When the pressure p ₁ and the pressure p ₂ are the same or almost the same (that is, when the pressure difference Δp becomes zero or a predetermined lower limit Δp _L ), the control device 15 closes the control valve 11 (step S1). S4).

  Further, if it is desired to continue the operation of the present invention to recover power / electric power, the heat source is switched in step S5 (that is, the flow path switching valve 14 is switched). When the heat source is switched, the process returns to step S2, but the fluid of the heat source 1 or the cooling source 2 that was flowing in one introduction pipe (for example, the first introduction pipe 16) in the previous step S2 is the other introduction pipe (for example, the second introduction pipe). The first and second heat exchangers HX1 and HX2 guided to the pipe 17) and heated (or cooled) in the previous step S2 are cooled (or heated) in the current step S2. In addition, when desired motive power / electric power is recovered and it is not desired to continue the operation of the cycle of the present invention, the heat source switching in step S2 is not executed, and the cycle of the present invention is terminated.

  FIG. 5 shows an apparatus configuration of a heat engine cycle apparatus 20 according to the second embodiment of the present invention. The heat engine cycle device 20 according to the second embodiment replaces the reciprocating flow expander 12 used in the first embodiment with a one-way flow expander 22 that allows the working fluid 19 to flow in only one direction, and before and after the one-way flow expander 22. A flow path switching valve 24 connected to the connecting pipe 18 is provided on the connecting pipe 18. In the second embodiment (and subsequent embodiments), the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. 5 and 6 omit the generator 13 for convenience of drawing.

  By configuring the heat engine cycle device 20 of the second embodiment as described above, a more general and easily available one-way flow expander 22 is used without using the reciprocating flow expander 12 having a special configuration. The cycle of the present invention can be activated. When the working fluid 19 flows from the first heat exchanger HX1 to the second heat exchanger HX2, the working fluid 19 flows in from the EX1 side of the one-way flow expander 22 and flows out from the EX2 side. When the control device 15 switches the heat source of the flow path switching valve 14 and the working fluid 19 flows from the second heat exchanger HX2 to the first heat exchanger HX1, the control device 15 The valve position is switched, and the process is performed so that the working fluid 19 flows in from the EX1 side of the one-way flow expander 22 (outflows from the EX2 side) and then returns to the first heat exchanger HX1.

  Note that the apparatus configuration of the second embodiment is disadvantageous in that the connecting pipe switching valve 24 is required and the piping of the connecting pipe 18 is complicated compared to the apparatus configuration of the first embodiment.

  FIG. 6 shows a configuration of a heat engine cycle device 30 according to the third embodiment of the present invention. The heat engine cycle device 30 of the third embodiment is provided with two unidirectional flow expanders 32a and 32b instead of the reciprocating flow expander 12 used in the first embodiment. The one-way flow expander 32a is driven by the working fluid 19 flowing only in the direction from the first heat exchanger HX1 to the second heat exchanger HX2, while the one-way flow expander 32b is driven by the second heat exchange. It is driven by the working fluid 19 flowing only in the direction from the heater HX2 to the first heat exchanger HX1. A connecting pipe 38 and a control valve 31 are further provided for moving and controlling the working fluid 19 in the one-way flow expander 32b. Opening and closing of the control valve 31 is controlled by the control device 15 according to the pressure (pressure difference) of the working fluid 19 around the one-way flow expander 32b.

  As described above, the cycle of the first embodiment is similar to the conventional Rankine cycle on each of the diagrams in FIG. 2 (however, there is no step-up process by the pump), but as shown in FIG. This is a dynamic cycle having temporal intermittency in the turbine output. In addition, the turbine output of the first embodiment draws a fluctuating time response curve that rapidly increases immediately after the control valve 11 is opened and maintains a constant output even after the control valve 11 is opened, and then decreases with the passage of time. Therefore, in order to make the present invention more practical, a device for leveling the turbine output / power is required.

  FIG. 7 shows the configuration of a heat engine cycle device 40 according to Embodiment 4 of the present invention. The heat engine cycle device 40 of the fourth embodiment is the same as the configuration of the first embodiment except that a power leveling device 431 connected to the generator 13 is further added. Examples of the power leveling device 431 include a device including a capacitor circuit such as an electric double layer capacitor, a flywheel, or a battery.

  As a device including a flywheel or a battery, for example, a kinetic energy regeneration system (for example, storing the shaft output of the expander 12 as mechanical power or power via a mechanical mechanism (gear, continuously variable transmission, etc.)). Kinetic Energy-Recovery System: KERS). Due to the presence of the power leveling device 431, intermittent and steep power as shown in FIG. 4 can be converted into more leveled power.

FIG. 8 shows a configuration of a heat engine cycle multiple connection system 50 according to Embodiment 5 of the present invention. In the heat engine cycle multi-connection system 50 of the fifth embodiment, a plurality of heat engine cycle devices configured as shown in the first embodiment are prepared (in FIG. 8, there are three devices, denoted as 10a, 10b, and 10c), These form a system connected to the heat source 1 or the cooling source 2 in parallel. Note that only one generator 53 is provided in the entire multi-connection system. In addition, a single shaft 533 or individual output shafts 533a, 533b, and 533c are connected to the generator 53 from the reciprocating flow expanders 12a, 12b, and 12c (differential gears that control the rotational speed and torque). Or may be connected via a transmission) by adjusting the opening / closing timing of the control valves 11a, 11b, 11c and the heat source switching timing of the flow path switching valves 14a, 14b, 14c by the control device 55. The superimposed turbine output L _{T system} becomes more continuous. The continuous turbine output is converted into electric power by the generator 53, and the converted electric power is further leveled by the power leveling device 531.

The controller 55 does not need to be prepared for each heat engine cycle device 10, and only one control device 55 is required for the entire multi-connection system, and the state of each heat engine cycle device 10 (for example, pressures p ₁ and p ₂ ). It is possible to monitor and operate the elements of the heat engine cycle devices 10a, 10b, 10c (for example, the control valves 11a, 11b, 11c and the flow path switching valves 14a, 14b, 14c). In the control device 55, when the recovered power / generated power (L _Ta , L _Tb , L _{Tc in the} figure) of the heat engine cycle devices 10a, 10b, 10c are superimposed as shown in FIG. Open / close timing of the control valves 11a, 11b, and 11c of the heat engine cycle devices 10a, 10b, and 10c and heat source switching timing of the flow path switching valves 14a, 14b, and 14c so as to obtain a proper value (L _{T system in the} figure). It is desirable to adjust (shift each other).

  FIG. 10 shows a configuration of a heat engine cycle multiple connection system 60 according to Embodiment 6 of the present invention. The heat engine cycle multiple connection system 60 according to the sixth embodiment is a system in which a plurality of heat engine cycle devices 10a, 10b, and 10c are connected in parallel to the heat source 1 or the cooling source 2 as in the fifth embodiment. Further, the difference from the fifth embodiment is that power generators 13a, 13b, and 13c are attached to the reciprocating flow expanders 12a, 12b, and 12c of the heat engine cycle devices 10a, 10b, and 10c of FIG. The device 631 is connected to each generator 13a, 13b, 13c. Accordingly, when the heat engine cycle multi-connection system 60 of the sixth embodiment is operated, the reciprocating flow expanders 12a, 12b, 12c collect power, and power is taken out separately for each of the generators 13a, 13b, 13c, and power leveling is performed. Supplied to the device 631. The electric power supplied to the power leveling device 631 is adjusted by adjusting the power generation timing by mechanically adjusting the opening timing of the control valves 11a, 11b, and 11c by the control device 65 as shown in the fifth embodiment. Alternatively, after the power is supplied to the power leveling device 631, an electric phase difference may be added to continuously level the power of the entire system.

  As described above in the device configurations of the fifth and sixth embodiments, the heat engine cycle devices 10a, 10b, and 10c of the present invention are connected in multiple, and the control devices 55 and 65 adjust the timing of control valve operation and heat source switching. Or the power leveling devices 531 and 631 are installed, the recovered power / generated power is continuously and leveled.

  In the fifth and sixth embodiments, the heat engine cycle devices 10a, 10b, and 10c based on the heat engine cycle device 10 of the first embodiment are connected. However, the present invention is not necessarily limited to this, and the present invention is not limited to the second embodiment. , 3 may be configured to be a multi-connection system in which apparatuses based on the heat engine cycle apparatuses 20 and 30 using the one-way flow expander are connected. That is, the expander 12 of Examples 5 and 6 includes various types other than the wells turbine and the rectifying impulse turbine that can be used as the reciprocating flow expander, the rotary vane type and the gear type expander that can be used as the reciprocating flow expander. It can be applied to any one-way flow expander, regardless of the type of expander.

  FIG. 11 shows a configuration of a heat engine cycle multiple connection system 70 according to Embodiment 7 of the present invention. The heat engine cycle multiple connection system 70 according to the seventh embodiment is a system in which a plurality of (for example, two) heat engine cycle devices 10 a and 10 b are connected in series to the heat source 1 or the cooling source 2. The difference from the fifth and sixth embodiments is that the fluid (refrigerant) used for the working fluid 19a accommodated in the upper cycle device 10a and the working fluid 19b accommodated in the lower cycle device 10b is different. It is. The upper working fluid 19a uses a fluid (for example, water) that can be adapted to a high temperature range of the heat source operating temperature level, and the lower working fluid 19b uses a fluid (for example, an HFO refrigerant) that can adapt to a low temperature range. It is preferable. By connecting multiple cycle devices 10a and 10b as in the seventh embodiment and selecting the working fluids 19a and 19b for each device, in some cases, a larger output is obtained than when a single working fluid is used. It becomes possible. For example, if a certain working fluid 19a cannot fully meet the operating temperature range of the heat source 1, if a working fluid 19b having other physical properties is used in the lower cycle device 10b, the heat source 1 can be seamlessly operated. The heat exchange cycle of the present invention can be carried out.

  In addition, the multiple connection system 50 and 60 of Example 5 and Example 6 in which the several heat engine cycle apparatus was connected in parallel with the heat source, and the multiple connection of Example 7 in which the several heat engine cycle apparatus was connected in series. It is also possible to configure a multi-connection system having a configuration in which the system 70 is combined.

(Cycle verification experiment)
In order to verify whether the heat engine cycle of the present invention really operates, a verification experiment described below was performed. FIG. 12 shows an outline of the experimental apparatus, and Table 2 below shows specifications of the apparatus components. As shown in Table 2, HFC245fa was selected as the working fluid 19. Plate-type heat exchangers were used for the first and second heat exchangers HX1 and HX2 serving as an evaporator / condenser. Both the heat source 1 and the cooling source 2 use water, the high temperature side heat source 1 fluid circulates while being heated by a resistance type plug heater, and the low temperature side cooling source 2 fluid is a cooling chiller. Circulation was performed while cooling. Switching between hot water and cold water to the first and second heat exchangers HX1, HX2 was manually performed by combining a three-way valve (flow path switching valve 14).

The adiabatic expansion in the reciprocating flow expander 12 was simulated by an expansion valve. This is a technique used in other Rankine cycle experiments. Further, the set pressure set by the control device 15 to open and close the control valve 11 is set to 1 MPa on the high temperature side and 0.1 MPa on the low temperature side (that is, the pressure difference Δp _SET = 0.9 MPa), and when this pressure difference is reached, the expansion valve And the working fluid 19 was adiabatically expanded. In the position shown in FIG. 12, the temperatures T ₁ and T ₂ of the working fluid 19 before and after the expansion valve, the pressures p ₁ and p ₂ , the lower temperatures T ₁ ′ and T ₂ ′ in the first and second heat exchangers (the working fluid side) ), And the mass transfer amount of the working fluid 19 was taken into a personal computer terminal at intervals of 2 seconds, and the pressure, enthalpy h ₁ and h _2, mass flow rate, and turbine output of the working fluid 19 before and after the expansion valve were calculated.

(Experimental result)
FIG. 13 shows the change over time of the pressures p ₁ and p ₂ before and after the expansion valve and the change over time of the enthalpies h ₁ and h ₂ when the heat engine cycle (switching of the working fluid 19) of the present invention is repeated three times. FIG. 14 shows the pressure difference Δp calculated from the experimental data such as the pressure, enthalpy, and temperature T ₁ , T ₁ ′, T ₂ , T ₂ ′ of the working fluid 19 as shown in FIG. The absolute value, the absolute value of enthalpy Δh (= h ₁ −h ₂ ), the mass flow rate m, and the turbine output are shown. Here, the turbine output is the product of the mass flow rate m and the enthalpy difference Δh, as shown in Equation 1. For convenience of explanation, FIG. 14 plots only the time response during the expansion valve opening period.

  From these FIGS. 13 and 14, it can be seen that a practically effective turbine output can be obtained from the novel heat engine cycle of the present invention (the instantaneous maximum output in the figure is about 267 W, and the average output is about 78 W). . In FIG. 13, the pressures p1 and p2 and the enthalpies h1 and h2 before and after the expansion valve (actually the part that becomes the expander) are alternately switched in size according to the time transition by switching the functions of the heat exchangers HX1 and HX2. I understand. In FIG. 14, during the expansion valve opening period (actually during the period when the control valve 11 is opened), the absolute value of the pressure difference Δp before and after the expander, the absolute value of the enthalpy difference Δh, and the mass flow rate are increased. It can be seen that the turbine output is obtained. Thus, the turbine output of the present invention is intermittent. In a normal Rankine cycle device, the working fluid pump continuously supplies working fluid to the evaporator, so that the turbine output is continuous.

  In this verification test, HFC245fa was selected as the working fluid 19, but qualitatively the same characteristics as those shown in FIGS. 13 and 14 should be obtained using the working fluid listed in Table 1 above. is there. In addition, energy of less than 2 kW was input to the heat source in this cycle verification experiment. In the case of an actual automobile engine, it is assumed that the amount of exhaust heat changes from several kW to nearly one hundred kW. In such a case, the apparatus of the present invention can sufficiently cope with the problem by increasing the heat source switching frequency in the flow path switching valve in accordance with the increase in heat input.

  The present invention is promising as a means for recovering a large amount of unused energy (low temperature and highly dispersible heat source) such as factory exhaust heat and automobile exhaust heat. In particular, since a working fluid pump is not required, downsizing of the apparatus, flexibility in layout design, and prevention of leakage of working fluid can be achieved, and therefore, the possibility of industrial use is very high. Furthermore, the use of a low-boiling working fluid is particularly useful in power recovery / power generation from a heat source at a temperature level below 200 ° C.

1 Heat source 2 Cooling source 10 (10a, 10b, 10c), 20, 30, 40, 50, 60 Heat engine cycle device 11 (11a, 11b, 11c) Control valve 12 (12a, 12b, 12c) Reciprocating flow expander ( Or forward and reverse rotating expander)
13 (13a, 13b, 13c) Generator 14 (14a, 14b, 14c) Flow path switching valve 15, 55, 65, 75 Control device 16 (16a, 16b, 16c) First introduction pipe 17 (17a, 17b, 17c) ) Second introduction pipe 18 (18a, 18b, 18c) Connection pipe 19 (19a, 19b, 19c) Working fluid 22 One-way flow expander 24 Connection pipe switching valve 31 Control valve 32a, 32b One-way flow expander 38 Connection pipe 50, 60, 70 Heat engine cycle multi-connection system 431, 531, 631, 731 Power leveling device 533 (533a, 533b, 533c) Output shaft

Claims (6)

First and second heat exchangers containing working fluid;
A connecting pipe that is connected to the first and second heat exchangers and that circulates the working fluid;
A control valve provided on the connecting pipe and controlling the flow of the working fluid by opening and closing the valve;
An expander that is provided on the connecting pipe and operates by circulation of the working fluid;
First and second introduction pipes for guiding a heat source fluid from a heat source or a cooling source to the first and second heat exchangers;
A flow path switching valve for switching the heat source fluid guided to the first and second introduction pipes;
When the pressure difference of the working fluid before and after the expander is monitored and the set upper limit value is reached, the control valve is opened to flow the working fluid, and after opening, the pressure difference reaches the set lower limit value A control device that switches the heat source fluid guided to the first and second introduction pipes by switching the flow path switching valve;
A heat engine cycle device comprising:   The heat engine cycle device according to claim 1, wherein a fluid that has a boiling point equal to or lower than that of water and that is suitable for a temperature range of the heat source is selected as the working fluid.   The heat engine cycle device according to claim 1 or 2, wherein the expander is a reciprocating flow expander or a forward and reverse rotation expander. The expander is a one-way flow expander;
A connection pipe switching valve for switching the flow path of the connection pipe;
The heat engine cycle device according to claim 1 or 2, wherein the control device switches the connecting pipe switching valve according to a flow direction of the working fluid to guide the working fluid to the expander. The expander is provided with a plurality of one-way flow expanders,
The control valve and the connecting pipe are prepared for the number of installation of the expander,
Some of the expanders are connected to the connecting pipe so as to distribute the working fluid from the first heat exchanger to the second heat exchanger, and the other expanders are connected to the second heat exchanger. Connected to the connecting pipe so as to circulate the working fluid to the first heat exchanger;
The heat engine cycle device according to claim 1 or 2, wherein the control device opens and closes the control valve to flow the working fluid.   The heat engine cycle device according to any one of claims 1 to 5, further comprising a power generator and a power leveling device connected to the power generator.

Images