JP7327023B2 - Expander and Rankine cycle device - Google Patents

Description

The present disclosure relates to expanders and Rankine cycle devices.

Patent Literature 1 discloses a refrigerating air conditioner with high refrigerating efficiency. This refrigeration air conditioner comprises a rotary valve for controlling the introduction of refrigerant into a cylinder and the discharge of refrigerant from the cylinder, and a housing having an internal space for rotatably inserting and holding the rotary valve. and an expander in which a solid lubricant layer is formed on at least one of the outer surface of the rotary valve and the inner surface of the housing facing the outer surface.

Patent Literature 2 discloses a Rankine cycle device with high power generation efficiency, a cogeneration system, and a method of operating the Rankine cycle device. This Rankine cycle device comprises a pump, an evaporator, an expander, a condenser and an internal heat exchanger. The internal heat exchanger exchanges heat between the working fluid discharged from the expander and the working fluid discharged from the pump. The temperature of the working fluid at the inlet of the expander is set such that the temperature of the working fluid at the outlet of the expander is above the saturation temperature on the high pressure side of the cycle.

JP-A-2001-272139 WO2014/087642

The present disclosure provides an expander with reduced heat transfer from the hot section to the cold section and improved efficiency, ie the ratio of electrical power generated to thermal energy supplied.

The present disclosure has a substantially cylindrical shape and includes a first passage extending from a first end surface to an outer diameter surface and a second passage extending from a second end surface on the back side of the first end surface to the outer diameter surface. and a working chamber arranged outside the outer diameter surface with respect to the valve and expanding the working fluid, the working fluid passing through the first passage from the first space facing the first end face and a Rankine cycle device using the expander in which the air is sucked into a working chamber and discharged from the working chamber through a second passage to a second space facing a second end face.

In the expander, the suction space, which is a high-temperature portion, is arranged on the first end surface side of the valve, and the discharge space, which is a low-temperature portion, is arranged on the opposite second end surface side of the valve. By separating the suction space from the discharge space and reducing the surface area of the boundary portion between the suction space and the discharge space, heat transfer from the high temperature portion to the low temperature portion is reduced. Therefore, by reducing the loss of thermal energy of the working fluid due to the temperature drop in the high-temperature part, the reduction in electric power obtained by converting the thermal energy is suppressed, so the efficiency of the expander can be improved.

Longitudinal cross-sectional view of the expander according to Embodiment 1 Enlarged view of the expansion mechanism part in Embodiment 1 Horizontal cross-sectional view along the AA plane in FIG. Schematic diagram showing the suction operation of the valve Schematic diagram showing the discharge operation of the valve A perspective view of the valve according to Embodiment 1 Front view of the valve in Embodiment 1 Top view of the valve in Embodiment 1 Configuration diagram of a Rankine cycle device according to Embodiment 2

(Knowledge, etc. on which this disclosure is based)
At the time when the inventors came up with the present disclosure, there was a technology of a power generation system having a Rankine cycle as one of the energy systems using natural energy such as sunlight or various types of waste heat. Such a Rankine cycle device generally operates an expander with a high-temperature and high-pressure working fluid, and generates power using power extracted from the working fluid by the expander.

Further, the expander comprises a working chamber whose volume changes due to the reciprocation of the piston, and an intake and exhaust mechanism that controls the introduction and discharge of the working fluid to and from the working chamber by a cylindrical valve housed in the housing, There is a technique for reducing friction between the valve and the housing by providing a solid lubricant layer on at least one of the outer surface of the valve and the inner surface of the housing.

In such an expander, the valve and the suction passage and the discharge passage communicating with the valve are arranged toward the top dead center from the working chamber so that the outer diameter of the expander does not become large from the viewpoint of reducing the size and weight. In addition, on the outer surface of the valve, an opening/closing groove for opening and closing the communication passage with the working chamber, an annular groove for constant communication with the passage provided in the housing, and the opening/closing groove and the annular groove are kept airtight. Therefore, a sealing portion and the like are provided to face the inner surface of the housing with a small clearance therebetween.

The open/close groove and the annular groove must have a predetermined cross-sectional area so as to increase the resistance when the working fluid flows, and the sealing portion must also have a width necessary to maintain airtightness. For this reason, the opening and closing groove, the annular groove, and the seal portion are arranged on the outer surface of the valve, and when considering the width of each of these, the total width becomes large, so the valve has a shape that is long in the axial direction compared to the diameter. was common. In addition, since the suction side of the open/close groove has a high pressure and the discharge side has a low pressure, a radial load acts on the valve due to the pressure difference between them. Since the valve is elongated in the axial direction compared to its diameter, the load due to the pressure difference acting on the valve is supported by the sliding surface between the seal portion and the housing. For this reason, the area of the outer diameter surface of the valve tends to increase also from the viewpoint of securing the area necessary for supporting the load.

Furthermore, in order to provide a suction path and a discharge path in the valve, it is necessary to provide a passage inside the valve so as not to communicate with the annular groove. In addition to these open/close grooves and annular grooves, it is necessary to arrange internal passages and the like in a complicated manner while ensuring that each of the open/close grooves, annular grooves, and passages has a cross-sectional area necessary for the flow of the working fluid. As a result, the surface area of the valve in contact with the working fluid is increased.

When such an expander is used in a Rankine cycle that extracts power from a high-temperature and high-pressure working fluid, the valve has a large area in contact with the working fluid, so heat transfer from the high-temperature intake gas to the valve and heat transfer from the valve to the low-temperature part heat transfer to the discharged gas increases. Furthermore, since the sealing portion of the valve and the housing face each other with a small clearance and the area of the sealing portion is large, the heat transfer from the valve to the housing increases, and the heat spreads from the housing to the entire expander.

Therefore, the inventors have discovered the problem that in an expander having a valve in the direction of the top dead center from the working chamber, the heat transfer from the high temperature part to the low temperature part increases and the efficiency decreases, and the inventors have solved the problem. have thus come to constitute the subject matter of this disclosure.

Accordingly, the present disclosure provides an expander with improved efficiency by reducing heat transfer from the hot section to the cold section. In this specification, an expander includes a mechanism section that expands a working fluid having thermal energy and a generator section that generates electric power using kinetic energy generated by the expansion of the working fluid. Efficiency refers to the ratio of electrical power generated to thermal energy supplied.

(Overview of one aspect of the present disclosure)
The expander according to the first aspect of the present disclosure includes:
A valve having a substantially cylindrical shape and having a first passage extending from a first end surface to an outer diameter surface and a second passage extending from a second end surface on the back side of the first end surface to the outer diameter surface. and,
a working chamber disposed outside the outer diameter surface with respect to the valve and configured to expand a working fluid;
has
The working fluid is
sucked into the working chamber via the first passage from the first space facing the first end face, and
The fluid is discharged from the working chamber through the second passage into the second space facing the second end face.

This first aspect is
A first end surface perpendicular to the rotation axis, a second end surface on the back side of the first end surface, an outer diameter surface formed in a circumferential direction at a constant distance from the rotation axis, and the outer diameter from the first end surface a valve having a first passageway to a surface and a second passageway from the second end surface to the outer diameter surface;
a working chamber disposed outside the outer diameter surface with respect to the valve and configured to expand a working fluid;
has
The working fluid is
Suction from the first space facing the first end face to the working chamber via the first passage, and the second end face from the working chamber via the second passage An expander that discharges into a facing second space.

In the expander, the technology according to the first aspect is to provide a suction space for high-temperature working fluid on the first end face side of the valve and a second end face side formed on the opposite side, that is, the back side of the first end face. A discharge space for the low-temperature working fluid is arranged. Therefore, the suction space and the discharge space are separated through the valve, and the surface area of the boundary portion between the suction space and the discharge space can be reduced. reduced. Since heat transfer is reduced in this way, the efficiency of the expander can be improved.

A second aspect of the present disclosure is, for example, in the expander according to the first aspect,
the valve
The axial length may be shorter than the outer diameter.

According to the second aspect, the length of the first passage and the second passage are shortened and the surface area of the valve is smaller, thus reducing heat transfer between the valve and the refrigerant. Also, since the outer diameter surface of the valve, that is, the area of the side surface is reduced, heat transfer from the valve to the cylinder block forming the working chamber is reduced. Therefore, heat transfer from the high temperature section to the low temperature section is further reduced. Therefore, the efficiency of the expander can be further improved.

A third aspect of the present disclosure is, for example, in the expander according to the first or second aspect,
a cylinder block including a housing in which the valve is rotatably accommodated, a plurality of the working chambers arranged around the housing, and bearings;
a shaft that shares a rotation axis with the valve, is integrated with the valve, and is rotatably supported by the bearing;
may be further provided.

According to the third aspect, since the valve is rotatably supported by the shaft and the bearing, the valve can be arranged so that the outer diameter surface of the valve and the housing that accommodates the valve do not contact each other. As a result, the friction between the valve and the housing is reduced, so that it is possible to reduce the heat loss and the loss due to the friction, thereby improving the efficiency of the expander.

A fourth aspect of the present disclosure is, for example, in the expander according to the third aspect,
The cylinder block is
A gap may be provided between each of the first end surface and the second end surface.

According to the fourth aspect, the heat transfer from the valve to the cylinder block can be reduced, and heat transfer can be further reduced, so that the efficiency of the expander can be further improved.

A fifth aspect of the present disclosure is, for example, in the expander according to the third or fourth aspect,
The thermal conductivity of the valve is
It may be lower than the thermal conductivity of the cylinder block.

According to the fifth aspect, since the thermal conductivity of the valve is low, heat transfer via the valve is further reduced, so that the efficiency of the expander can be further improved.

A sixth aspect of the present disclosure is a Rankine cycle device using the expander according to any one of the first to fifth aspects.

According to the sixth aspect, since the expander with improved efficiency is applied to the Rankine cycle device, the efficiency of the Rankine cycle is also improved. can.

Hereinafter, embodiments will be described in detail with reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially the same configurations may be omitted. This is to avoid the following description from becoming more redundant than necessary and to facilitate understanding by those skilled in the art.

It should be noted that the accompanying drawings and the following description are provided to allow those skilled in the art to fully understand the present disclosure and are not intended to limit the claimed subject matter thereby.

(Embodiment 1)
Embodiment 1 will be described below with reference to FIGS. 1 to 8. FIG.

[1-1. composition]
In FIG. 1 , an expander 100 includes a closed container 102 , and a generator section 110 and a mechanism section 120 that are housed in the closed container 102 . A suction chamber 146 and a discharge chamber 176 are formed in the mechanical portion 120 . In addition, lower spaces 178a, 178b, and 178c are formed inside the sealed container 102 . The space in the closed container 102 is filled with a working fluid, such as HFO, HFC, or hydrocarbons such as isopentane, which is normally used in the Rankine cycle.

Oil 104 is stored in the bottom of the lower space 178b. An oil supply mechanism 174 provided in the mechanism section 120 is immersed in the oil 104 . A suction pipe 106 and a discharge pipe 108 are attached to the sealed container 102 . The suction pipe 106 is connected to the suction chamber 146, and the discharge pipe 108 is connected to the lower space 178c.

The generator section 110 consists of a stator 112 with a copper wire wound around an iron core, and a rotor 114 with a built-in permanent magnet. A stator 112 is fixed to the inner surface of the closed container 102 . The rotor 114 is arranged on the inner diameter side of the stator 112 and attached to the shaft 128 of the mechanism section 120 .

Next, the mechanism section 120 will be described in detail with reference to FIGS. 2 to 5. FIG.

2 and 3, the mechanism section 120 is composed of a lower block 150, a cylinder block 122, and the like. The mechanism part 120 is fixed to the closed container 102 by a method such as welding the outer diameter surface of the lower block 150 and the inner surface of the closed container 102 . The lower block 150 also has a lower bearing 158 which is a cylindrical hole. The lower block 150 also has a communication hole 152 that connects the upper and lower spaces of the lower block 150 .

Cylinder block 122 is fixed to the upper surface of lower block 150 . A discharge chamber 176 surrounded by the cylinder block 122 and the lower block 150 is formed by covering the lower end surface of the cylinder block 122 with the lower block 150 . The cylinder block 122 also has an upper bearing 126 as a bearing 125, which is a cylindrical hole in the center. Above the upper bearing 126, a housing 142, which is a space having a cylindrical inner surface and which shares the center line with the upper bearing 126, is formed. Furthermore, a plurality of discharge passages 148a and 148b are provided around the upper bearing 126. As shown in FIG. The discharge passages 148 a and 148 b communicate between the spaces 122 a and 122 b provided in the bottom surface of the housing 142 and the discharge chamber 176 .

A disk-shaped swash plate 134 is fixed to the shaft 128 via a holder 135 . In the swash plate 134 , the normal line of an annular flat portion formed on the outer diameter side of the swash plate 134 is inclined with respect to the central axis of the shaft 128 . Shaft 128 is rotatably inserted into upper bearing 126 and lower bearing 158 with a small clearance. A thrust bearing 138 using a ball bearing is arranged between the holder 135 and the lower block 150 .

Around the upper bearing 126, cylinders 124a to 124f, which are six cylindrical holes, are arranged at regular intervals.

Hereinafter, the configuration will be described with respect to the combination of the cylinder 124a, the piston 132a and the working chamber 140a, but since the configuration is the same for other combinations, the corresponding constituent elements will be denoted by symbols b to f. omitted.

As mainly shown in FIGS. 3 and 4, a suction/discharge hole 144a is provided between the housing 142 and the cylinder 124a to communicate the space inside the housing 142 and the space inside the cylinder 124a. The suction/discharge hole 144a has a substantially rectangular cross section. The depth DH is less than half the height of the suction/discharge hole 144a, that is, the vertical width HH and the horizontal width WH. As a result, the spatial volume in the suction/discharge hole 144a is reduced while ensuring the cross-sectional area in the flow direction of the working fluid.

A piston 132a is reciprocally inserted into the cylinder 124a.
, the piston 132a and the head 154 form a working chamber 140a.

Pistons 132a are pivotably connected to the outer diameter side of swash plate 134 via a pair of shoes 136a and 137a, thereby determining the positions of pistons 132a within cylinder 124a. The inclination angle of the swash plate 134 determines the stroke L (not shown) of the piston 132a.

Since such pistons 132a-132f (132b, 132c, 132e, 132f are not shown) are arranged at equal intervals around the shaft 128, these pistons 132a-132f interlock with each other with a predetermined phase difference. reciprocating motion.

As shown in FIG. 2, the valve 160 is housed within a housing 142 with a housing cover 156 attached to the upper end surface of the housing 142 . A suction chamber 146 surrounded by a housing 142, a housing cover 156, and a valve 160 is formed.

As shown in FIGS. 6 and 7, the valve 160 has a generally cylindrical shape with an upper first end surface 162 , a lower second end surface 166 and an outer diameter surface 170 . The height HV of valve 160 is less than the diameter or outer diameter DV of valve 160 .

The valve 160 also has a first passage 164 that is a recess spanning the first end surface 162 and the outer diameter surface 170 and a second passage 168 that is a recess spanning the second end surface 166 and the outer diameter surface 170 . It has

In FIG. 7, the heightwise width of the first passage 164 is the sum of the dimensions M and J. In FIG. A cylindrical surface having a width of dimension K is provided on the underside of the first passageway 164 to form a seal. Also, the width in the height direction of the second passage 168 is the sum of the dimension M and the dimension K. As shown in FIG. Above the second passageway 168, a cylindrical surface having a width of dimension J is provided to form a seal.

Note that the dimension J and the dimension K, which are the vertical widths of the seal portion, are about half the dimension M. As shown in FIG.

Further, the dimension M is substantially equal to the height of the suction/discharge hole 144a, that is, the vertical width HH. The portion of the dimension M determines the vertical position of the valve 160 so as to face the suction/discharge hole 144a.

The height HV of the valve 160 is approximately twice the dimension M as it is the sum of the dimensions M, J and K. The height HV of the valve 160 is within three times the dimension M and within three times the height of the suction/discharge hole 144a, that is, the vertical width HH.

In the valve 160, the range of angles for providing the first passage 164 and the second passage 168 is selected so that the suction/discharge hole 144a can be opened and closed at a predetermined timing.

In FIG. 8, the direction O is the direction in which the piston 132a is at the top dead center when the direction O is positioned at the center of the suction/discharge hole 144a. The range of directions B through E about direction O is outside the range of first passageway 164 and second passageway 168 . Therefore, the suction/discharge hole 144a is closed by the valve 160 at the top dead center of the piston 132a. Although the volume of the working chamber 140a is minimized at the top dead center, a small gap is provided between the piston 132a and the head 154, so the volume does not become zero. The sum of the volume of the working chamber 140a at the top dead center and the volume of the suction/discharge hole 144a is called dead volume.

A first passage 164 is arranged in the range from direction B to C, and as shown in FIG. do.

In the range from direction C to D, the suction/discharge hole 144a is closed by the valve 160. As shown in FIG.

A second passage 168 is arranged in a range from direction D to E, and as shown in FIG. do.

An example of the specifications of the first passage 164 and the second passage 168 provided in the valve 160 is indicated by counterclockwise angles with respect to the direction O. degrees, direction D is 180-190 degrees, and direction E is 165-170 degrees.

When this valve 160 is used, when the center of the suction/discharge hole 144a and the direction D of the valve 160 coincide, the piston 132a is positioned at the bottom dead center, and the upper end surface of the piston 132a is positioned at a stroke L from the head 154. Nearby.

Further, when the center of the suction/discharge hole 144a and the direction C of the valve 160 are aligned, the upper end surface of the piston 132a is positioned about 1/4 of the stroke L from the head 154. As shown in FIG. Therefore, during the rotation of the valve 160 from direction C to D, in which the suction/discharge hole 144a is closed by the valve 160, the piston 132a is displaced downward and the volume of the working chamber 140a is increased by about four times.

The expansion ratio of the working fluid by the expander 100 is the ratio of the combined volume of the working chamber 140a and the suction/discharge hole 144a at the end of suction and the start of discharge. Therefore, even if the stroke L of the piston 132a is the same, the larger the dead volume, the smaller the expansion ratio. Therefore, in order to achieve the required expansion ratio with a smaller expander 100, it is desirable that the dead volume is small.

The angle from B to E is 20 to 30 degrees, but the length of this arc BE is longer than the width WH of the suction/discharge hole 144a. Therefore, when the suction/discharge hole 144a and the arc BE face each other, the first passage 164 and the second passage 168 do not communicate with each other via the suction/discharge hole 144a.

The outer diameter DV of the valve 160 is larger than the outer diameter DP of the piston 132a. For this reason, the width WH of the suction/discharge hole 144a is increased so that the valve 160 can seal the suction/discharge hole 144a while securing the necessary cross-sectional area of the flow path.

The valve 160 shares the rotation axis with the shaft 128 by fitting the holding portion 130, which is a small-diameter portion provided at the upper end of the shaft 128, with a cylindrical hole 172 provided at the center of the valve 160. is fixed in place.

A gap is provided between the second end face 166 which is the end face on the lower side of the valve 160 and the bottom face of the housing 142 . The gap (dimension G) between the spaces 122a and 122b, which are the portions on the outer diameter side, is larger than the gap between the end of the upper bearing 126 and the second end face 166. As shown in FIG.

The clearance between valve 160 and housing 142 is greater than the clearance between shaft 128 and upper bearing 126 .

Both the piston 132a and the cylinder block 122 are made of an aluminum alloy. Also, the valve 160 is made of stainless steel having a lower thermal conductivity than the cylinder block 122 .

When the center of the suction/discharge hole 144a and the direction C of the valve 160 are aligned, the upper end surface of the piston 132a is positioned approximately 1/4 of the stroke L from the head 154. As shown in FIG. Further, the height of the suction/discharge hole 144a, that is, the width HH in the vertical direction, is about 1/4 of the stroke L so that the entire width of the piston 132a and the head 154 at this time is open.

The first passage 164 and the second passage 168 have a height HV of the valve 160 from the viewpoint of minimizing the area of the outer diameter surface 170 of the valve 160 while ensuring the flow passage cross-sectional area and sealing portion. is less than the stroke L (not shown) of the piston 132a, preferably within 70% of the stroke L of the piston 132a.

[1-2. motion]
The operation of the expander 100 configured as described above will be described below.

A high-temperature, high-pressure working fluid flows into the suction chamber 146 from the suction pipe 106 .

In the state of the valve 160 shown in FIG. 3, the first passage 164 communicates with the suction/discharge hole 144d and the working chamber 140d, and is in the suction state shown in FIG. 132d, 144d). At this time, since the pressure in the working chamber 140d is high pressure and the lower surface of the piston 132d is low pressure, a downward force acts on the piston 132d.

The working chambers 140a, 140b, 140c communicate with the second passage 168 through suction/discharge holes 144a, 144b, 144c, respectively, and are in the discharge state shown in FIG. The second passage 168 communicates with the discharge chamber 176 via discharge passages 148a, 148b. As a result, the working chambers 140a, 140b, and 140c have the same low pressure as the discharge chamber 176 on the lower surface of the pistons, and no pressure acting force acts on these pistons 132a, 132b, and 132c.

Accordingly, a downward force acts on the piston 132d to move the piston 132d downward and drive the shaft 128 clockwise.

As a result, as the piston 132d descends, as indicated by the arrow in FIG. 4, the high-temperature, high-pressure working fluid flows from the suction chamber 146 to the working chamber 140d via the first passage 164 and the suction/discharge hole 144d. influx. Also, since the pistons 132a, 132b, 132c rise, as indicated by the arrows in FIG. Working fluid flows out. The working fluid in the discharge chamber 176 is discharged from the discharge pipe 108 via the communication hole 152 and the lower spaces 178a, 178b, 178c.

The working chambers 140e and 140f are in a state where the volumes of the working chambers 140e and 140f are expanded after the suction/discharge holes 144e and 144f are closed by the valve 160. FIG. Therefore, once the expander 100 starts rotating, the working fluid in the working chambers 140e and 140f expands as the volume expands, so the pressure in the working chambers 140e and 140f gradually decreases from the high pressure. However, since the opening/closing timing of the valve 160 is selected so that the pressure in the working chambers 140e and 140f is always higher than the low pressure on the lower surface of the pistons 132e and 132f, downward force is exerted on the pistons 132e and 132f. works.

Further, in the state of the valve 160 shown in FIG. 3, a downward force acts on the pistons 132d, 132e, and 132f to generate driving force to rotate the shaft 128. As shown in FIG. As the shaft 128 rotates, each working chamber sequentially sucks the working fluid, so that driving force can be obtained continuously. Moreover, by arranging six or more working chambers, the working fluid can be sucked in continuously, so that the expander can be stably driven.

As the rotor 114 of the generator section 110 rotates together with the shaft 128 in this way, the generator section 110 generates electricity and obtains electric power. Moreover, by arranging six or more working chambers, fluctuations in the torque generated by the expander 100 are reduced, and the output power is stabilized.

In addition, as the shaft 128 rotates, the oil 104 stored in the bottom of the sealed container 102 is pumped up by the oil supply mechanism 174, and the sliding parts between the lower bearing 158 and the upper bearing 126 and the shaft 128, the thrust bearing 138, and the Oil 104 is supplied to the sliding portions between the pistons 132a-f and the cylinders 124a-f for lubrication.

Next, heat transfer around the valve 160 will be described.

By locating an inlet chamber 146 with hot working fluid on a first end face 162 of the valve and a discharge chamber 176 with cold working fluid on an opposite second end face 166 of the valve, hot air is drawn through the valve 160 . It separates the working fluid from the cold working fluid. The hot working fluid contacts the first end surface 162 and the first passageway 164 . First passageway 164 is a recess that spans first end surface 162 and outer diameter surface 170 . The heightwise width of the first passage 164 is the sum of the dimensions M and J. This dimension is substantially equal to the minimum value of the sum of the height of the suction/discharge hole 144a, that is, the vertical width HH and the vertical seal width. Therefore, the path of the first passage 164 is short and the surface area in contact with the hot working fluid is small.

Also, the cold working fluid is in contact with the second end face 166 and the second passageway 168 . The second passageway 168 is a recess that spans the second end surface 166 and the outer diameter surface 170 . The heightwise width of the second passageway 168 is the sum of the M and K dimensions. This dimension is also substantially equal to the minimum value obtained by adding the height of the suction/discharge hole 144a, that is, the vertical width HH, and the vertical seal width. Therefore, the path of the second passage 168 is short and the surface area in contact with the cold working fluid is also small.

By reducing the surface area of the valve 160 located at the interface between the hot working fluid and the cold working fluid in this way, heat transfer from the hot section to the cold section is reduced.

The height HV of valve 160 is smaller than the diameter or outer diameter DV of valve 160, and the area of outer diameter surface 170 is smaller. Also, the height HV of the valve 160 is less than the stroke L of the piston 132a, preferably within 70% of the stroke L of the piston 132a. This further shortens the first and second passages 164 and 168 and reduces heat transfer between the valve 160 and the working fluid due to the reduced surface area of the valve 160 . Also, since the area of the outer diameter surface 170 of the valve 160 is small, heat transfer from the valve 160 to the cylinder block 122 via the housing 142 is reduced.

Further, the height HV of the valve 160 is within three times the height of the suction/discharge hole 144a, that is, the vertical width HH. As a result, the area of the outer diameter surface 170 of the valve 160 is reduced while ensuring the height of the suction/discharge hole 144a, that is, the width HH in the vertical direction, and the seal width. Heat transfer to 122 is reduced.

Due to the high pressure acting on the first passage 164 of the valve 160 and the low pressure acting on the second passage 168 of the valve 160 , the valve 160 is radially loaded. Since the gap between the valve 160 and the housing 142 is larger than the gap between the shaft 128 and the upper bearing 126, even if the shaft 128 is displaced within the gap of the upper bearing 126, the valve 160 and the housing 142 do not contact each other. is ensured. In this way, the radial load acting on the valve 160 due to the pressure difference is supported by the shaft 128 and the upper bearing 126 , thereby preventing contact between the outer diameter surface 170 of the valve 160 and the housing 142 .

Cylinder block 122 has a gap between it and the end face of valve 160 . This suppresses heat conduction from the valve 160 to the cylinder block 122, further reducing heat transfer.

Valve 160 has a lower thermal conductivity than cylinder block 122 . This can further reduce heat transfer through the valve 160 .

[1-3. effects, etc.]
As described above, in the present embodiment, the expander 100 has the valve 160 and the working chamber 140a. The valve 160 has a generally cylindrical shape and has a first passageway 164 extending from a first end surface 162 to an outer diameter surface 170 and a second passageway 168 extending from a second end surface 166 to the outer diameter surface 170 . The working chamber 140 a is arranged on the outer diameter side of the valve 160 . A working fluid is drawn into the working chamber through the first passage from the space facing the first end face, and from the working chamber through the second passage facing the second end face. It is discharged into space.

As a result, the suction space and the discharge space are separated by the valve 160, and the surface area of the valve 160, which is the boundary portion between the suction space and the discharge space, is reduced. reduced. Therefore, by reducing the loss of thermal energy of the working fluid due to the temperature drop in the high-temperature part, the reduction in electric power obtained by converting the thermal energy is suppressed, so the efficiency of the expander 100 can be improved.

Also, since high pressure acts on the first passage 164 of the valve 160 and low pressure acts on the second passage 168 of the valve 160 , a radial load acts on the valve 160 . Since the gap between the valve 160 and the housing 142 is larger than the gap between the shaft 128 and the upper bearing 126, even if the shaft 128 is displaced within the gap of the upper bearing 126, the valve 160 and the housing 142 do not contact each other. is ensured. In this way, the radial load acting on the valve 160 due to the pressure difference is supported by the shaft 128 and the upper bearing 126 , thereby preventing contact between the outer diameter surface 170 of the valve 160 and the housing 142 .

As a result, the valve 160 and the housing 142 are heated to a high temperature, difficult to lubricate, and difficult to form an oil film because the outer diameter surface 170 has a missing portion due to the first passage 164 and the second passage 168. Friction is reduced because the load does not need to be supported between Further, since the valve 160 and the housing 142 do not come into direct contact with each other, heat transfer due to heat conduction from the valve 160 can be suppressed.

As in the present embodiment, the expander 100 may have a cylindrical shape whose axial length is shorter than its outer diameter.

This reduces the transfer of heat between the valve 160 and the working fluid due to the reduced surface area of the valve 160 due to the short first and second passages 164 and 168 . Also, valve 1
Since the area of the outer diameter surface 170 of 60 is reduced, heat transfer from the valve 160 to the housing 142 is reduced, thereby reducing heat transfer from the hot section to the cold section. Therefore, the efficiency of the expander 100 can be improved by further reducing heat transfer.

As in this embodiment, the expander 100 includes a housing 142 in which a valve 160 is rotatably accommodated, a plurality of working chambers 140a to 140f formed around the housing 142, and an upper bearing 126 as a bearing 125. and a shaft 128 that shares a rotation axis with the valve 160 and is integrated with the valve 160 and rotatably supported by an upper bearing 126 .

Accordingly, by supporting the valve 160 with the shaft 128 and the upper bearing 126, contact between the outer diameter surface 170 of the valve 160 and the housing 142 is prevented, and friction between the valve 160 and the housing 142 is reduced. be. Therefore, while reducing the heat loss, it is possible to reduce the loss due to the friction of the valve 160 and improve the efficiency.

As in the present embodiment, the expander 100 may have a gap between the cylinder block 122 and the end surface of the valve 160 .

This reduces heat transfer from valve 160 to cylinder block 122 . Therefore, the efficiency of the expander 100 can be improved by further reducing heat transfer.

As in the present embodiment, in the expander 100, the valve 160 is made of a material having a lower thermal conductivity than the cylinder block 122, at least part of which forms the working chamber 140a.

This further reduces heat transfer through valve 160 . Therefore, the efficiency of the expander 100 can be improved by further reducing heat transfer.

(Embodiment 2)
Embodiment 2 will be described below with reference to FIG.

[2-1. composition]
In FIG. 9 , Rankine cycle device 200 includes expander 100 , evaporator 202 , condenser 206 , pump 208 and internal heat exchanger 210 . The evaporator 202, the expander 100, the internal heat exchanger 210, the condenser 206, the pump 208, the internal heat exchanger 210, and the evaporator 202 are pipe-connected in this order to form a closed cycle in which the working fluid flows. there is

The evaporator 202 is a heat exchanger that absorbs the heat energy generated by the heat source 204 and uses a finned-tube heat exchanger. A high-temperature working fluid (for example, high-temperature steam) supplied from the heat source 204 and a working fluid of the Rankine cycle device 200 exchange heat in the evaporator 202 . Thereby, the working fluid of the Rankine cycle device 200 is heated and evaporated.

The condenser 206 cools and condenses the working fluid by exchanging heat between the outside air and the working fluid discharged from the expander 100, and releases heat to the outside air. A known heat exchanger such as a fin-tube heat exchanger is used as the condenser 206 .

Pump 208 draws in and pressurizes the working fluid flowing out of condenser 206 and supplies the pressurized working fluid to evaporator 202 via internal heat exchanger 210 . A positive displacement gear pump is used as the pump 208 .

The internal heat exchanger 210 is a so-called regenerative heat exchanger, and heat-exchanges the working fluid discharged from the expander 100 and the working fluid discharged from the pump 208 . Specifically, the internal heat exchanger 210 has a low temperature side channel 212 and a high temperature side channel 214 . The working fluid discharged from the pump 208 flows through the low temperature side flow path 212 . The working fluid discharged from the expander 100 flows through the high temperature side passage 214 . A plate heat exchanger, for example, can be used as the internal heat exchanger 210 .

An organic working fluid can be preferably used as the working fluid for the Rankine cycle device 200 . Organic working fluids typically have low boiling points. Therefore, if the organic working fluid is used, power can be generated with high efficiency even when the temperature of the high-temperature fluid supplied from the heat source 204 is less than about 300.degree.

[2-2. motion]
Rankine cycle device 200 is operated, for example, in the following procedure.

First, the pump 208 is operated to start the operation of the Rankine cycle device 200 . When the circulation amount of the working fluid reaches a predetermined circulation amount, the high-temperature fluid is supplied from the heat source 204 to the evaporator 202 . The working fluid of the Rankine cycle device 200 receives heat from the high-temperature fluid in the evaporator 202 and changes into a superheated vapor-phase working fluid. The hot, vapor-phase working fluid is sent to the expander 100 . In the mechanism section 120 of the expander 100, the pressure energy of the working fluid is converted into mechanical energy to drive the generator section 110. As shown in FIG. Electric power is thereby generated in the generator unit 110 . The working fluid discharged from the expander 100 flows into the condenser 206 via the high temperature side flow path 214 of the internal heat exchanger 210 . The working fluid is cooled by ambient air and condenses in condenser 206 . The condensed working fluid is pressurized by the pump 208 and sent to the evaporator 202 again via the low temperature side flow path 212 of the internal heat exchanger 210 .

In the Rankine cycle device 200 using the internal heat exchanger 210, if the cycle pressure conditions (high pressure and low pressure) are the same, the higher the temperature of the working fluid at the inlet of the expander 100, the more the inlet of the expander 100 The difference in enthalpy between and the exit becomes large. As a result, the power generation efficiency of the Rankine cycle device can be improved.

[2-3. effects, etc.]
As described above, in the present embodiment, the Rankine cycle device 200 uses the expander 100 described in the first embodiment.

As a result, heat transfer from the high temperature section to the low temperature section in the expander 100 is reduced even when the high temperature working fluid is drawn into the expander 100 . Therefore, since the efficiency of the expander 100 is improved, the power generation efficiency of the Rankine cycle device 200 can be improved.

Note that the above-described embodiment is for illustrating the technology in the present disclosure, and various changes, replacements, additions, omissions, etc. can be made within the scope of the claims or equivalents thereof.

(Other embodiments)
In the first embodiment, as an example of the expander, which is one of the fluid machines, the valve 160 is made of stainless steel, which has a lower thermal conductivity than the cylinder block 122 . However, it is not limited to this. For example, the bulb may be made of resin or other material with low thermal conductivity. Alternatively, a layer with low heat conductivity may be provided only on the surface of the bulb. Further, the heat conductivity may be substantially lowered by making the inside of the bulb hollow. Any of these methods can suppress heat transfer through the valve.

In the first embodiment, as an example of the expander (fluid machine), the upper bearing 126 and the lower bearing 158 as the bearing 125 are sliding bearings. However, it is not limited to this. For example, a bearing using a more durable sliding member such as a bush may be used. Rolling bearings may also be used, in which case friction loss can be reduced compared to sliding bearings.

In Embodiment 1, as an example of an expander (fluid machine), thrust bearing 138 is a ball bearing using steel balls as rolling elements. However, it is not limited to this. For example, other types of thrust bearings such as roller bearings using cylindrical rollers or slide bearings using dynamic pressure or static pressure may be used as the rolling elements.

In the first embodiment, as an example of the expander (fluid machine), six working chambers are provided, but for example, seven or other plural number may be provided.

In Embodiment 2, the evaporator 202 using a fin-tube heat exchanger is shown as an example of the Rankine cycle device, which is one of the devices constituting the power generation system. However, the evaporator is not limited to this, and known heat exchangers such as plate heat exchangers and double tube heat exchangers can be used as the evaporator.

In the second embodiment, as an example of the Rankine cycle device (power generation system), the condenser 206 uses a fin-tube heat exchanger. However, not limited to this, for example, as a condenser, a heat exchanger such as a plate heat exchanger or a double tube heat exchanger is used, and a heat medium such as water flowing through a separately provided heat medium circuit and a working fluid to exchange heat and cool the working fluid.

In the second embodiment, as an example of the Rankine cycle device (power generation system), the positive displacement gear pump is used as the pump 208 . However, the pump is not limited to this, and for example, other general positive displacement or turbo pumps can be used as the pump. For example, positive displacement pumps such as piston pumps, vane pumps, and rotary pumps can be used. A centrifugal pump, a mixed flow pump, an axial flow pump, or the like can be used as the turbo pump.

The present disclosure is applicable to expanders and Rankine cycle devices with rotary valves. Specifically, the present disclosure is applicable not only to systems that generate only electric power, but also to cogeneration systems such as CHP systems.

100 expander 102 airtight container 104 oil 106 suction pipe 108 discharge pipe 110 generator section 112 stator 114 rotor 120 mechanism section 122 cylinder block 124a, 124b, 124c, 124d, 124e, 124f cylinder 125 bearing 126 upper bearing 128 shaft 1 30 Holding portion 132a, 132b, 132c, 132d, 132e, 132f Piston 134 Swash plate 135 Holder 136a, 136d, 137a, 137d Shoe 138 Thrust bearing 140a, 140b, 140c, 140d, 140e, 140f Working chamber 142 Housing 144a, 144b, 144c , 144d, 144e, 144f suction/discharge hole 146 suction chamber 148a, 148b discharge passage 150 lower block 152 communication hole 154 head 156 housing cover 158 lower bearing 160 valve 162 first end face 164 first passage 166 second end face 168 second 2 passage 170 outer diameter surface 172 hole 174 lubricating mechanism 176 discharge chamber 178a, 178b, 178c lower space 200 Rankine cycle device 202 evaporator 204 heat source 206 condenser 208 pump 210 internal heat exchanger 212 low temperature side passage 214 high temperature side flow path

Claims (6)

A valve having a substantially cylindrical shape and having a first passage extending from a first end surface to an outer diameter surface and a second passage extending from a second end surface on the back side of the first end surface to the outer diameter surface. and,
a working chamber disposed outside the outer diameter surface with respect to the valve and configured to expand a working fluid;
has
The working fluid is
sucked into the working chamber via the first passage from the first space facing the first end face, and
discharged from the working chamber through the second passage into a second space facing the second end surface;
inflator. The valve is
The axial length is shorter than the outer diameter,
The expander according to claim 1. a cylinder block including a housing in which the valve is rotatably accommodated, a plurality of the working chambers arranged around the housing, and bearings;
a shaft that shares a rotation axis with the valve, is integrated with the valve, and is rotatably supported by the bearing;
further comprising
The expander according to claim 1 or 2. The cylinder block is
having a gap between each of the first end surface and the second end surface;
The expander according to claim 3. The thermal conductivity of the valve is
lower than the thermal conductivity of the cylinder block;
The expander according to claim 3 or 4. A Rankine cycle device using the expander according to any one of claims 1 to 5.

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