Compressor and method of operating same

Abstract

A compressor (100) comprises: an oil-free compressor body (2) that compresses a gas; an exhaust heat recovery unit (3) that recovers exhaust heat from the compressor body (2) by using water W; a working fluid line (L2) to which the exhaust heat recovery unit (3) is connected and through which the water (W) flows; a temperature adjustment valve (4) that is connected to the working fluid line (L2) and adjusts the temperature of the water (W); a bypass line (L3) that branches from the working fluid line (L2) at a branching point (P1) upstream of the temperature adjustment valve (4) and downstream of the exhaust heat recovery unit (3) and merges with the working fluid line (L2) at a merging point (P2) downstream of the temperature adjustment valve (4) in the flow direction of the water (W); an electric valve (51) that is connected to the bypass line (L3) and controls a flow rate of the water (W) flowing through the bypass line (L3); a heat supply unit (6) that is connected downstream of the merging point (P2) and supplies heat by using the heat of the water (W); and a control unit (10) that controls the operation of the electric valve (51) in accordance with the heat supply status of the heat supply unit (6).

Description

Compressor and Method of Operating the Same

[0001] The present disclosure relates to a compressor and a method of operating the same.

[0002] Patent Document 1 discloses an oil-free compressor. Compressed gas from an oil-free compressor is cooled by heat exchange with a low-temperature aqueous solution in an interstage air cooler and a discharge-stage air cooler. During this process, the aqueous solution recovers heat from the compressed gas and increases in temperature. The temperature-increased aqueous solution is cooled by heat exchange with water in another heat exchanger. At this time, the water recovers heat from the aqueous solution and increases in temperature. In this way, hot water is produced by utilizing the exhaust heat of the compressor.

[0003] Japanese Unexamined Patent Publication No. Hei 1-170788

[0004] In Patent Document 1, when there is no demand for hot water from a heat demand destination (when no heat is supplied to the heat demand destination), heat exchange between the aqueous solution and water is not performed. As a result, the aqueous solution is not cooled, the temperature of the aqueous solution flowing through the interstage air cooler and the discharge-stage air cooler rises, and the cooling efficiency of the compressed gas decreases. Therefore, the compressor is forced to operate in low-performance operation (non-energy-saving operation) with insufficient cooling. In addition, a temperature control valve (flow rate adjustment valve) for adjusting the temperature of hot water may be required to supply heat in accordance with the heat demand from the heat demand destination. However, in this case, even when the temperature control valve is fully opened, it causes a certain degree of pressure loss (hereinafter also referred to as pressure drop), so the flow rate of the aqueous solution for cooling the compressor is also limited. Therefore, when there is no demand for hot water from the heat demand destination, there is a risk that the cooling efficiency of the compressed gas may be further reduced.

[0005] An object of the present disclosure is to suppress a decrease in performance of a compressor depending on a heat supply state to a heat demand destination in the compressor and a method of operating the compressor.

[0006] This disclosure provides a compressor comprising: an oil-free compressor body for compressing gas; a heat recovery unit for recovering waste heat from the compressor body using a working fluid; a working fluid line to which the heat recovery unit is connected and through which the working fluid flows; a temperature control valve connected to the working fluid line for adjusting the temperature of the working fluid; a bypass line that branches off from the working fluid line at a branching point upstream of the temperature control valve and downstream of the heat recovery unit in the flow direction of the working fluid, and rejoins the working fluid line at a confluence point downstream of the temperature control valve; a control valve connected to the bypass line for controlling the flow rate of the working fluid flowing through the bypass line; a heat supply unit connected downstream of the confluence point for supplying heat to a heat demander using the heat of the working fluid; and a control unit that controls the operation of the control valve according to the heat supply status of the heat supply unit. The control unit may also issue a control command to open the control valve when the heat supply unit is not supplying heat. Furthermore, the control unit may issue a control command to close the control valve when the heat supply unit is supplying heat.

[0007] According to the above configuration, the control valve is controlled according to the heat supply status of the heat supply unit, and the flow rate of the working fluid flowing through the bypass line is adjusted. Therefore, the flow rate of the working fluid flowing to the heat recovery unit can be adjusted regardless of the opening degree of the temperature control valve, and the compressor body can be sufficiently cooled. In particular, when the heat supply unit is not supplying heat (not supplying working fluid), temperature adjustment by the temperature control valve is unnecessary, so it is conceivable to fully open the temperature control valve to ensure a sufficient flow rate of working fluid. However, as mentioned above, even when the temperature control valve is fully open, there is a certain degree of pressure loss, so the flow rate of the working fluid is also limited. In contrast, with the above configuration, the control valve is opened and water flows through the bypass line, so the flow rate of the working fluid to the heat recovery unit can be increased regardless of the opening degree of the temperature control valve. As a result, the amount of heat recovered in the heat recovery unit increases, that is, the amount of cooling of the compressor body increases. Therefore, the deterioration of the compressor performance when heat is not supplied can be suppressed. Also, when the heat supply unit is supplying heat, the control valve is closed, so the bypass line that bypasses the temperature control valve is closed. Therefore, the temperature control valve functions accurately, and the desired heat supply can be achieved.

[0008] The heat supply unit may have a heat exchanger that exchanges heat between the working fluid and a heat transfer medium.

[0009] According to the above configuration, heat can be recovered from the working fluid into any heat transfer medium, and the heat transfer medium can be supplied to the heat demanding party.

[0010] The temperature control valve may be a self-operating control valve whose opening degree is automatically adjusted according to the temperature of the working fluid.

[0011] The above configuration allows for a mechanically simpler and more efficient design compared to using a solenoid valve or the like. Here, "self-operated" refers to a system where the opening degree is automatically adjusted according to the temperature of the working fluid, without electronic control. For example, a self-operated temperature control valve is a tube in which a fluid that expands or contracts according to the temperature of the working fluid is arranged in a ring shape, and the working fluid flows through the inside. Although the opening degree of a self-operated temperature control valve cannot be freely controlled, the flow rate of the working fluid can be freely adjusted by combining the temperature control valve with a bypass line and a control valve.

[0012] The cross-sectional area of ​​the flow path of the piping constituting the bypass line may be greater than or equal to the cross-sectional area of ​​the flow path of the piping constituting the working fluid line between the branching point and the confluence point.

[0013] According to the above configuration, the pressure loss of the working fluid flowing through the bypass line can be reduced, making it easier for the working fluid to flow through the bypass line, while also ensuring a sufficient flow rate of the working fluid.

[0014] The compressor body may include a first-stage compressor body and a second-stage compressor body that further compresses the gas discharged from the first-stage compressor body, and the heat recovery unit may include an intercooler that cools the gas discharged from the first-stage compressor body and an aftercooler that cools the gas discharged from the second-stage compressor body, and the intercooler and the aftercooler may be arranged in series in the working fluid line.

[0015] With the above configuration, exhaust heat can be recovered by both the intercooler and the aftercooler, thus improving the efficiency of exhaust heat recovery.

[0016] The heat recovery unit may further include an oil cooler for cooling the oil supplied to the first-stage compressor body and the second-stage compressor body, and the oil cooler, the intercooler, and the aftercooler may be arranged in series in the working fluid line.

[0017] With the above configuration, waste heat can be recovered by the oil cooler, intercooler, and aftercooler, thus improving the efficiency of waste heat recovery.

[0018] The heat recovery unit may further include a first cooling jacket for cooling the first-stage compressor body and a second cooling jacket for cooling the second-stage compressor body, and the oil cooler, the first cooling jacket, the second cooling jacket, the intercooler, and the aftercooler may be arranged in series in the working fluid line.

[0019] With the above configuration, exhaust heat can be recovered by the oil cooler, the first cooling jacket, the second cooling jacket, the intercooler, and the aftercooler, thus improving the efficiency of exhaust heat recovery.

[0020] The control unit may receive a signal indicating the heat supply status of the heat supply unit and control the operation of the control valve in accordance with the signal.

[0021] With the above configuration, the heat supply status of the heat supply unit can be identified based on the heat demand from the heat demand source, and the control valve can be easily controlled.

[0022] The system further comprises a housing that accommodates the compressor body and the heat recovery unit, and the temperature control valve, the bypass line, and the control valve may be located inside the housing.

[0023] With the above configuration, since the temperature control valve, bypass line, and control valve are arranged inside the housing, the temperature drop of the working fluid can be suppressed, and the decrease in the efficiency of heat recovery can be suppressed.

[0024] The system further comprises a housing that accommodates the compressor body and the heat recovery unit, and the temperature control valve, the bypass line, and the control valve may be located outside the housing.

[0025] With the above configuration, the temperature control valve, bypass line, and control valve are located outside the housing, allowing for a more compact compressor housing and increasing the flexibility of the layout design around the housing.

[0026] Another aspect of this disclosure provides a method for operating a compressor comprising: an oil-free compressor body for compressing gas; a heat recovery unit for recovering waste heat from the compressor body using a working fluid; a working fluid line to which the heat recovery unit is connected and through which the working fluid flows; a temperature control valve connected to the working fluid line for adjusting the temperature of the working fluid; a bypass line that branches off from the working fluid line at a branching point upstream of the temperature control valve and downstream of the heat recovery unit in the direction of flow of the working fluid, and rejoins the working fluid line at a confluence point downstream of the temperature control valve; a control valve connected to the bypass line for controlling the flow rate of the working fluid flowing through the bypass line; and a heat supply unit connected downstream of the confluence point for supplying heat to a heat demander using the heat of the working fluid, wherein the operation of the control valve is controlled according to the heat supply status of the heat supply unit.

[0027] According to this disclosure, in a compressor and its operating method, it is possible to suppress the deterioration of the compressor's performance due to the heat supply conditions to the outside.

[0028] A schematic diagram of the compressor according to the embodiment of this disclosure. A schematic diagram showing the water flow when the operating state of the compressor shown in Figure 1 is switched. A schematic diagram showing the water flow when the operating state of the compressor shown in Figure 1 is switched. A schematic diagram of the compressor according to a first modified example of the embodiment. A schematic diagram of the compressor according to a second modified example of the embodiment.

[0029] Embodiments will be described below with reference to the drawings. The same or corresponding elements are denoted by the same reference numerals throughout the drawings, and redundant detailed descriptions will be omitted.

[0030] (Embodiment) The compressor 100 shown in Figure 1 compresses a gas G such as air or refrigerant, supplies the compressed gas G (hereinafter referred to as compressed gas G) to a pressure demand destination 9, and provides water (hot water) W heated using the heat generated during compression to a heat demand destination 8.

[0031] The compressor 100 comprises a housing 1, a compressor body 2, a heat recovery unit 3, a temperature control valve 4, a bypass unit 5, a temperature acquisition unit 6, a heat supply unit 6, a cooling unit 7, a control unit 10, a first fluid line L1, and a second fluid line L2 (an example of a working fluid line). Gas G flows through the first fluid line L1. A pump 11 is connected to the second fluid line L2, and when the pump 11 operates, water W (an example of a working fluid) flows through it. The water W may be industrial water, groundwater such as well water, tap water, reclaimed water, or saline water containing salt. Alternatively, the working fluid may be a fluid other than water.

[0032] The housing 1 contains the compressor body 2, the heat recovery unit 3, the control unit 10, the first fluid line L1, and a portion of the second fluid line L2. In this embodiment, the temperature control valve 4 and the bypass unit 5 are also located inside the housing 1.

[0033] (Compressor Body) The compressor body 2 is a two-stage compressor, comprising a first-stage compressor body 21 on the low-pressure side and a second-stage compressor body 22 on the high-pressure side. The first-stage compressor body 21 and the second-stage compressor body 22 are oil-free screw compressors, and the first-stage compressor body 21 and the second-stage compressor body 22 are operated by the rotation of motors controlled by inverters.

[0034] The first-stage compressor body 21 compresses and discharges gas G drawn in from outside the housing 1 through the suction port. The second-stage compressor body 22 further compresses the gas G discharged from the first-stage compressor body 21 and supplies it to the pressure demand destination 9 outside the housing 1 through the discharge port. Compressor body

[0035] (Heat Recovery Unit) The heat recovery unit 3 uses water W to recover heat from the compressor body 2 as waste heat. The heat recovery unit 3 includes an oil cooler 31, an intercooler 32, an aftercooler 33, a first cooling jacket 34, and a second cooling jacket 35.

[0036] The oil cooler 31, intercooler 32, aftercooler 33, first cooling jacket 34, and second cooling jacket 35 are connected to the second fluid line L2 through which water W flows. The oil cooler 31, first cooling jacket 34, second cooling jacket 35, intercooler 32, and aftercooler 33 are arranged in this order from upstream to downstream in the direction of water W flowing through the second fluid line L2. In other words, the oil cooler 31, first cooling jacket 34, second cooling jacket 35, intercooler 32, and aftercooler 33 are arranged in series in the second fluid line L2. The intercooler 32 and aftercooler 33 are connected to the first fluid line L1 through which gas G flows. The first stage compressor body 21, intercooler 32, second stage compressor body 22, and aftercooler 33 are arranged in this order from upstream to downstream in the direction of gas G flow.

[0037] The oil cooler 31 exchanges heat between the oil O and water W supplied to the first-stage compressor body 21 and the second-stage compressor body 22. This cools the oil O and heats the water W. After being cooled by the oil cooler 31, the oil O is supplied to the bearings of the screw rotor of the compressor body 2 for cooling, lubrication, etc. In the figure, the lines through which the oil O flows are shown as dashed lines.

[0038] The intercooler 32 exchanges heat between the compressed gas G discharged from the first-stage compressor body 21 and the water W flowing through the second fluid line L2. Similarly, the aftercooler 33 exchanges heat between the compressed gas G discharged from the second-stage compressor body 22 and the water W flowing through the second fluid line L2. As a result, the compressed gas G is cooled and the water W is heated.

[0039] The first cooling jacket 34 is positioned outside the first-stage compressor body 21 and exchanges heat with the first-stage compressor body 21. This cools the first-stage compressor body 21 and heats the water W. Similarly, the second cooling jacket 35 is positioned outside the second-stage compressor body 22 and exchanges heat with the second-stage compressor body 22. This cools the second-stage compressor body 22 and heats the water W.

[0040] (Temperature Control Valve) The temperature control valve 4 is connected to the second fluid line L2 for adjusting the temperature of water W flowing through the second fluid line L2. The temperature control valve 4 of the present embodiment is a self-operated regulating valve that adjusts the opening degree by expanding or contracting according to the temperature of the water W. Here, the self-operated regulating valve is of a type that does not involve electronic control, and whose opening degree is automatically adjusted according to the temperature of the working fluid. For example, the self-operated temperature control valve 4 is an annularly arranged pipe filled with a fluid having the property of expanding or contracting according to the temperature of the water W, allowing the working fluid to flow inside the pipe. When the temperature of the water W drops, the temperature control valve 4 expands to narrow the pipe passage, thereby reducing (throttling) the flow rate of the water W passing through the temperature control valve 4. On the other hand, when the temperature of the water W rises, the temperature control valve 4 contracts to widen the pipe passage, thereby increasing the flow rate of the water W passing through the temperature control valve 4.

[0041] (Bypass Section) The bypass section 5 is configured such that the water W bypasses the temperature control valve 4. The bypass section 5 includes a bypass line L3 and a motor-operated valve 51 (an example of a control valve).

[0042] The bypass line L3 branches off from the second fluid line L2 at a branch point P1 located upstream of the temperature control valve 4 and downstream of the aftercooler 33, and joins the second fluid line L2 at a confluence point P2 located downstream of the temperature control valve 4.

[0043] The flow passage cross-sectional area of the pipes constituting the bypass line L3 is not less than the flow passage cross-sectional area of the pipes constituting the second fluid line L2 between the branch point P1 and the confluence point P2.

[0044] The motor-operated valve 51 is connected to the bypass line L3 and controls the flow rate of the water W flowing through the bypass line L3. In the present embodiment, the motor-operated valve 51 is of a flow rate control type or an on-off control type that operates under the control of a control unit 10 described later.

[0045] (Heat Supply Unit) In this embodiment, the heat supply unit 6 supplies hot water W to the heat demand destination 8. The heat supply unit 6 includes a first heat supply valve 61 provided in the second fluid line L2, and a heat supply line L4 that branches off from the second fluid line L2 and extends to the heat demand destination 8, and also extends from the heat demand destination 8 to rejoin the second fluid line L2. The heat supply line L4 branches off from the second fluid line L2 at a branching point P3 upstream of the first heat supply valve 61 and downstream of the confluence point P2, and rejoins the second fluid line L2 at a confluence point P4 downstream of the first heat supply valve 61. A second heat supply valve 62 is provided in the heat supply line L4 that branches off from the second fluid line L2 and extends to the heat demand destination 8. A third heat supply valve 63 is provided in the heat supply line L4 that extends from the heat demand destination 8 to rejoin the second fluid line L2.

[0046] The first to third heat supply valves 61, 62, and 63 are of the on / off control type and operate in response to a signal indicating heat demand from the heat demand destination 8. When there is heat demand from the heat demand destination 8, the first heat supply valve 61 is closed and the second and third heat supply valves 62 and 63 are opened. When there is no heat demand from the heat demand destination 8, the first heat supply valve 61 is opened and the second and third heat supply valves 62 and 63 are closed. The signal from the heat demand destination 8 is also sent to the control unit 10, which will be described later.

[0047] (Cooling section) The cooling section 7 is located downstream of the first heat supply valve 61 in the second fluid line L2 and cools the water W. The cooling section 7 has a heat exchanger 71 that cools the water W and heats the refrigerant C. In the second fluid line L2, there is a line that passes through the heat exchanger 71 and a line that bypasses the heat exchanger 71, and these are connected by a three-way valve 72. Here, the water W that has been cooled by passing through the heat exchanger 71, or the water W that has bypassed the heat exchanger 71, flows to the oil cooler 31 in the second fluid line L2. In this embodiment, the second fluid line L2 is configured in such a way that water W circulates.

[0048] (Control Unit) The control unit 10 controls the operation of each part of the compressor 100 (the compressor body 2 and the waste heat recovery unit 3). The control unit 10 is constituted by hardware such as a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory), and software installed in the hardware.

[0049] The control unit 10 controls the operation of the electric valve 51 according to the heat supply status of the heat supply unit 6. The heat supply status of the heat supply unit 6 is detected by receiving a signal indicating heat demand from the heat demand destination 8. Alternatively, it may be detected based on the opening / closing states of the first to third heat supply valves 61 to 63.

[0050] When the heat supply unit 6 does not supply heat (when there is no heat demand from the heat demand destination 8), the control unit 10 issues a control command to open the electric valve 51 (see FIG. 2A). In the present embodiment, the electric valve 51 is fully opened to increase the flow rate of water W flowing through the bypass line L3, and decrease the flow rate of water W passing through the temperature control valve 4.

[0051] When the heat supply unit 6 supplies heat, the control unit 10 closes the electric valve 51 (see FIG. 2B). In the present embodiment, the electric valve 51 is gradually fully closed from the fully open state, so that the flow rate of water W flowing through the bypass line L3 is gradually decreased, and the flow rate of water W passing through the temperature control valve 4 is gradually increased. Specifically, the control unit 10 keeps the electric valve 51 in an open state for a first period (for example, 30 seconds), and after the first period elapses, slowly throttles the opening degree over a second period (for example, 20 seconds or more). Note that the times set as the first period and the second period are not limited to the above, and may be appropriately changed according to the rotation speed of the compressor body 2, the discharge pressure of the compressor body 2, the pipe diameter (flow path cross-sectional area) of the second fluid line L2, the pipe diameter (flow path cross-sectional area) of the bypass line L3, and the like. Alternatively, the closing of the electric valve 51 may be switched immediately from fully open to fully closed when the heat supply unit 6 is switched to a heat supply state.

[0052] (Effects of the Embodiment) Since the electric valve 51 is controlled according to the heat supply status of the heat supply unit 6, the flow rate of water W flowing through the bypass line L3 is adjusted. Therefore, the flow rate of water W flowing to the heat recovery unit 3 can be adjusted regardless of the opening degree of the temperature control valve 4, and the compressor body 2 can be sufficiently cooled. In particular, when the heat supply unit 6 does not supply heat (does not supply hot water W), temperature adjustment with the temperature control valve 4 is unnecessary, so it is conceivable to fully open the temperature control valve 4 to ensure a sufficient flow rate of water W. However, even when the temperature control valve 4 is fully open, there is a certain degree of pressure loss, and there is a limit to the increase in the flow rate of water W. In contrast, in this embodiment, since the electric valve 51 is opened and water W flows through the bypass line L3, the flow rate of water W to the heat recovery unit 3 can be increased regardless of the opening degree of the temperature control valve 4. As a result, the amount of heat recovered in the heat recovery unit 3 increases, that is, the amount of cooling of the compressor body 2 increases. Therefore, the performance degradation of the compressor 100 when no heat is supplied can be suppressed. Furthermore, in this embodiment, when the heat supply unit 6 supplies heat, the electric valve 51 is closed, so the bypass line L3 that bypasses the temperature control valve 4 is closed. As a result, the temperature control valve 4 functions accurately, and the desired heat supply can be achieved.

[0053] Furthermore, because the temperature control valve 4 is self-operated, it can be constructed mechanically and simply compared to electromagnetic valves, etc. Although the opening degree of the self-operated temperature control valve 4 cannot be freely controlled, the flow rate of water W can be freely adjusted by combining the temperature control valve 4 with the bypass line L3 and the electric valve 51.

[0054] Furthermore, since the flow path cross-sectional area of ​​the piping constituting the bypass line L3 is defined as described above, the pressure loss of the water W flowing through the bypass line L3 can be reduced, making it easier for the water W to flow through the bypass line L3 and ensuring a sufficient flow rate of water W.

[0055] Furthermore, since waste heat can be recovered by the oil cooler 31, the first cooling jacket 34, the second cooling jacket 35, the intercooler 32, and the aftercooler 33, the efficiency of waste heat recovery is improved.

[0056] Furthermore, the heat supply status of the heat supply unit 6 can be identified based on the heat demand from the heat demand destination 8, and the electric valve 51 can be easily controlled.

[0057] (First Modified Example of the Embodiment) As shown in Figure 3, the heat supply unit 6 may have a heat exchanger 64 that exchanges heat between hot water W flowing in the heat supply line L4 and a heat transfer medium H. The heat exchanger 64 is located downstream of the second heat supply valve 62 and upstream of the third heat supply valve 63 in the heat supply line L4. In the heat exchanger 64, the hot water W is cooled and the heat transfer medium H is heated. This allows heat to be recovered from the hot water W into any heat transfer medium and supplied to the heat demand destination 8.

[0058] (Second Modification of the Embodiment) As shown in Figure 4, the temperature control valve 4 and the bypass section 5 may be located outside the housing 1. This makes the housing 1 more compact.

[0059] In the above embodiment, the control of the electric valve 51 is illustrated by the control unit 10 which controls the operation of each part of the compressor 100 (compressor body 2 and heat recovery unit 3). However, the control of the electric valve 51 may also be performed by a separate control unit (controller) dedicated to the electric valve 51, distinct from the control unit 10.

[0060] In the above embodiment, a case in which the compressor body 2 is configured as a two-stage type was described, but the compressor body 2 is not limited to a two-stage type, and may be a one-stage type or a three-stage or more type.

[0061] Furthermore, although the electric valve 51 in the above embodiment was a two-way valve, it may be a valve with three or more directions that can be switched in more than two directions. Also, although an electric electric valve 51 was described as an example of a control valve, the control valve may be an electromagnetic solenoid valve instead of the electric valve 51.

[0062] In the above embodiment, the heat recovery unit 3 had a first cooling jacket 34 and a second cooling jacket 35, but the first cooling jacket 34 and the second cooling jacket 35 can be omitted.

[0063] In the above embodiment, the first to third heat supply valves 61, 62, and 63 were of the on / off control type, but they may also be of the manual type that are opened and closed manually according to the heat demand of the heat demanding party, and manual opening and closing is performed as follows: If there is a heat demand at the heat demanding party 8, the first heat supply valve 61 is closed and the second and third heat supply valves 62 and 63 are opened. If there is no heat demand at the heat demanding party 8, the first heat supply valve 61 is opened and the second and third heat supply valves 62 and 63 are closed.

[0064] The three-way valve 72 in the above embodiment may be a three-way valve that switches the flow path, or it may be a three-way temperature control valve that controls the temperature of the working fluid (water W) on the downstream side to a constant level.

[0065] This disclosure may include the following embodiments: (Embodiment 1) A compressor comprising: an oil-free compressor body for compressing gas; a heat recovery unit for recovering waste heat from the compressor body using a working fluid; a working fluid line to which the heat recovery unit is connected and through which the working fluid flows; a temperature control valve connected to the working fluid line for adjusting the temperature of the working fluid; a bypass line that branches off from the working fluid line at a branching point upstream of the temperature control valve and downstream of the heat recovery unit in the flow direction of the working fluid, and merges with the working fluid line at a confluence point downstream of the temperature control valve; a control valve connected to the bypass line for controlling the flow rate of the working fluid flowing through the bypass line; a heat supply unit connected downstream of the confluence point for supplying heat to a heat demander using the heat of the working fluid; and a control unit that controls the operation of the control valve according to the heat supply status of the heat supply unit. (Embodiment 2) The compressor according to Embodiment 1, wherein the control unit issues a control command to open the control valve when the heat supply unit is not supplying heat. (Aspect 3) The compressor according to aspect 1 or 2, wherein the control unit issues a control command to close the control valve when the heat supply unit supplies heat. (Aspect 4) The compressor according to any one of aspects 1 to 3, wherein the heat supply unit has a heat exchanger that exchanges heat between the working fluid and a heat transfer medium. (Aspect 5) The compressor according to any one of aspects 1 to 4, wherein the temperature control valve is a self-operating control valve whose opening degree is automatically adjusted according to the temperature of the working fluid. (Aspect 6) The compressor according to any one of aspects 1 to 5, wherein the flow path cross-sectional area of ​​the piping constituting the bypass line is greater than or equal to the flow path cross-sectional area of ​​the piping constituting the working fluid line between the branching point and the confluence point. (Aspect 7) The compressor according to any one of aspects 1 to 6, wherein the compressor body comprises a first-stage compressor body and a second-stage compressor body that further compresses the gas discharged from the first-stage compressor body, the heat recovery unit comprises an intercooler that cools the gas discharged from the first-stage compressor body and an aftercooler that cools the gas discharged from the second-stage compressor body, and the intercooler and the aftercooler are arranged in series in the working fluid line.(Aspect 8) The compressor according to aspect 7, wherein the heat recovery unit further comprises an oil cooler for cooling the oil supplied to the first-stage compressor body and the second-stage compressor body, and the oil cooler, the intercooler, and the aftercooler are arranged in series in the working fluid line. (Aspect 9) The compressor according to aspect 8, wherein the heat recovery unit further comprises a first cooling jacket for cooling the first-stage compressor body and a second cooling jacket for cooling the second-stage compressor body, and the oil cooler, the first cooling jacket, the second cooling jacket, the intercooler, and the aftercooler are arranged in series in the working fluid line. (Aspect 10) The compressor according to any one of aspects 1 to 9, wherein the control unit receives a signal from the heat demand destination indicating the heat supply status of the heat supply unit and controls the operation of the control valve according to the signal. (Aspect 11) A compressor according to any one of aspects 1 to 10, further comprising a housing that houses the compressor body and the heat recovery unit, wherein the temperature control valve, the bypass line, and the control valve are arranged inside the housing. (Aspect 12) A compressor according to any one of aspects 1 to 10, further comprising a housing that houses the compressor body and the heat recovery unit, wherein the temperature control valve, the bypass line, and the control valve are arranged outside the housing. (Aspect 13) A method for operating a compressor comprising: an oil-free compressor body for compressing gas; a heat recovery unit for recovering waste heat from the compressor body using a working fluid; a working fluid line to which the heat recovery unit is connected and through which the working fluid flows; a temperature control valve connected to the working fluid line for adjusting the temperature of the working fluid; a bypass line that branches off from the working fluid line at a branching point upstream of the temperature control valve and downstream of the heat recovery unit in the flow direction of the working fluid, and rejoins the working fluid line at a confluence point downstream of the temperature control valve; a control valve connected to the bypass line for controlling the flow rate of the working fluid flowing through the bypass line; and a heat supply unit connected downstream of the confluence point for supplying heat to a heat demander using the heat of the working fluid, wherein the operation of the control valve is controlled according to the heat supply status of the heat supply unit.

[0066] This application is based on a claim of priority to Japanese Patent Application No. 2025-038501, filed on March 11, 2025. Japanese Patent Application No. 2025-038501 is incorporated herein by reference.

[0067] 1 Housing 2 Compressor body 3 Heat recovery unit 4 Temperature control valve 5 Bypass unit 6 Heat supply unit 7 Cooling unit 8 Heat demand destination 9 Pressure demand destination 10 Control unit 11 Pump 21 First stage compressor body 22 Second stage compressor body 31 Oil cooler 32 Intercooler 33 Aftercooler 34 First cooling jacket 35 Second cooling jacket 51 Electric valve (control valve) 61 First heat supply valve 62 Second heat supply valve 63 Third heat supply valve 64 Heat exchanger 71 Heat exchanger 72 Three-way valve 100 Compressor C Refrigerant G Compressed gas (gas) H Heat transfer medium L1 First fluid line L2 Second fluid line (working fluid line) L3 Bypass line L4 Heat supply line P1, P3 Branch point P2, P4 Confluence point W Water (hot water) (working fluid)

Claims

1. A compressor comprising: an oil-free compressor body for compressing gas; a heat recovery unit for recovering waste heat from the compressor body using a working fluid; a working fluid line to which the heat recovery unit is connected and through which the working fluid flows; a temperature control valve connected to the working fluid line for adjusting the temperature of the working fluid; a bypass line that branches off from the working fluid line at a branching point upstream of the temperature control valve and downstream of the heat recovery unit in the direction of flow of the working fluid, and rejoins the working fluid line at a confluence point downstream of the temperature control valve; a control valve connected to the bypass line for controlling the flow rate of the working fluid flowing through the bypass line; a heat supply unit connected downstream of the confluence point for supplying heat to a heat demander using the heat of the working fluid; and a control unit that controls the operation of the control valve according to the heat supply status of the heat supply unit.

2. The compressor according to claim 1, wherein the control unit issues a control command to open the control valve when the heat supply unit does not supply heat.

3. The compressor according to claim 1, wherein the control unit issues a control command to close the control valve when the heat supply unit supplies heat.

4. The compressor according to claim 1, wherein the heat supply unit has a heat exchanger that exchanges heat between the working fluid and a heat transfer medium.

5. The compressor according to claim 1 or 2, wherein the temperature control valve is a self-operating control valve whose opening degree is automatically adjusted according to the temperature of the working fluid.

6. The compressor according to claim 1 or 2, wherein the flow path cross-sectional area of ​​the piping constituting the bypass line is equal to or greater than the flow path cross-sectional area of ​​the piping constituting the working fluid line between the branching point and the confluence point.

7. The compressor according to claim 1 or 2, wherein the compressor body comprises a first-stage compressor body and a second-stage compressor body for further compressing the gas discharged from the first-stage compressor body, the heat recovery unit comprises an intercooler for cooling the gas discharged from the first-stage compressor body and an aftercooler for cooling the gas discharged from the second-stage compressor body, and the intercooler and the aftercooler are arranged in series in the working fluid line.

8. The compressor according to claim 7, wherein the heat recovery unit further includes an oil cooler for cooling the oil supplied to the first-stage compressor body and the second-stage compressor body, and the oil cooler, the intercooler, and the aftercooler are arranged in series in the working fluid line.

9. The compressor according to claim 8, wherein the heat recovery unit further comprises a first cooling jacket for cooling the first-stage compressor body and a second cooling jacket for cooling the second-stage compressor body, and the oil cooler, the first cooling jacket, the second cooling jacket, the intercooler, and the aftercooler are arranged in series in the working fluid line.

10. The compressor according to claim 1 or 2, wherein the control unit receives a signal indicating heat demand from the heat demand source and controls the operation of the control valve in accordance with the signal.

11. The compressor according to claim 1 or 2, further comprising a housing that accommodates the compressor body and the heat recovery unit, wherein the temperature control valve, the bypass line, and the control valve are arranged inside the housing.

12. The compressor according to claim 1 or 2, further comprising a housing that accommodates the compressor body and the exhaust heat recovery unit, wherein the temperature control valve, the bypass line, and the control valve are arranged outside the housing.

13. A method for operating a compressor comprising: an oil-free compressor body for compressing gas; a heat recovery unit for recovering waste heat from the compressor body using a working fluid; a working fluid line to which the heat recovery unit is connected and through which the working fluid flows; a temperature control valve connected to the working fluid line for adjusting the temperature of the working fluid; a bypass line that branches off from the working fluid line at a branching point upstream of the temperature control valve and downstream of the heat recovery unit in the flow direction of the working fluid, and rejoins the working fluid line at a confluence point downstream of the temperature control valve; a control valve connected to the bypass line for controlling the flow rate of the working fluid flowing through the bypass line; and a heat supply unit connected downstream of the confluence point for supplying heat to a heat demander using the heat of the working fluid, wherein the operation of the control valve is controlled according to the heat supply status of the heat supply unit.

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