JP2008175402A - Operating method of refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power recovering loss in starting a compressor of a refrigerating cycle device effectively recovering energy generated by expansion of fluid. <P>SOLUTION: The refrigerating cycle device is constituted by successively connecting the compressor 1, a radiator 2, an expander 3 and an evaporator 5, and comprises a fan 9 for the radiator and a fan 11 for the evaporator. In starting the compressor 1, at least one of the fan 9 for the radiator and the fan 11 for the evaporator is stopped or the air volume is reduced in comparison with that in a normal operation, so that differential pressure necessary for driving the expander 3 can be quickly secured, and a time to drive the expander 3 can be shortened, thus the power recovering loss of the expander 3 in starting the compressor 1 can be reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for operating a refrigeration cycle apparatus using an expander.

  In recent years, as a means for further improving the efficiency of the refrigeration cycle, an expander is provided in place of the expansion valve, and in the process of expansion of the refrigerant, the pressure energy is recovered in the form of electric power or power by the expander. A power recovery cycle that only reduces the input of the compressor has been proposed (see, for example, Patent Document 1).

  FIG. 17 shows a conventional refrigeration cycle apparatus described in Patent Document 1. In FIG. The compressor 1 is driven by a driving means (not shown) such as a traveling engine and sucks and compresses the refrigerant. The refrigerant discharged from the compressor 1 is cooled by the radiator 2. The refrigerant flowing out of the radiator 2 flows into the expander 3 to convert and recover the expansion energy of the refrigerant into mechanical energy (rotational energy), and supply the recovered mechanical energy (rotational energy) to the generator 4. Electric power is generated. The refrigerant expanded under reduced pressure by the expander 3 is evaporated by the evaporator 5 and then sucked into the compressor 1 again.

Since the refrigerant is decompressed while the expansion energy is converted into mechanical energy by the expander 3, the refrigerant flowing out of the radiator 2 undergoes a phase change along the isentropic line (c → d) as shown in FIG. While reducing enthalpy. Therefore, the enthalpy of the evaporator 5 can be increased by the amount of expansion work Δiexp as compared with the case of simply adiabatic expansion without performing expansion work when the refrigerant is decompressed (when changing the isenthalpy). Capability can be increased. Further, since mechanical energy (rotational energy) can be supplied to the generator 4 by the amount of expansion work Δiexp, the generator 4 can generate electric power for Δiexp. By supplying the electric power to the compressor 1, it is possible to reduce the electric power necessary for driving the compressor 1, and thus it is possible to improve the COP (coefficient of performance) of the refrigeration cycle.
JP 2000-329416 A

  However, since the expander 3 is driven by utilizing the high / low pressure difference in the refrigeration cycle, the conventional configuration described above does not stabilize the refrigeration cycle when the compressor 1 is started, and the high / low pressure difference is sufficient. In the state that is not secured, the torque required to drive the expander 3 is insufficient, and the compressor 1 continues to operate without the expander 3 being driven. At this time, since the expander 3 is stopped, the power is not recovered, and when the compressor 1 and the expander 3 are directly connected to one another, the load on the compressor 1 is increased and the power consumption is increased. There was a problem. In addition, since the refrigeration cycle is closed before and after the expander 3, the low pressure of the refrigeration cycle is abnormally lowered and no refrigerant is supplied to the compressor 1, and the cooling effect of the compressor 1 by the refrigerant is obtained. The compressor 1 may be damaged, and in the case of the scroll compressor 1, the normal revolving motion is impaired, the efficiency decreases due to the leakage of the refrigerant, the blade wear is accelerated due to excessive load on the blade, etc. There was a risk that this would occur.

The present invention solves the above-mentioned conventional problems, and at the time of starting the compressor, by controlling the capabilities of the radiator and the evaporator, the differential pressure necessary for the expander to be driven quickly can be secured. An object of the present invention is to provide a refrigeration cycle apparatus that minimizes power recovery loss at the time of starting the compressor and improves the reliability of the compressor.

  In order to solve the above-mentioned conventional problems, the operation method of the refrigeration cycle apparatus of the present invention includes a compressor, a radiator, an expander, and an evaporator, which are sequentially connected, and a radiator capacity control means and an evaporator. At least one of the capacity control means is provided, and at the time of starting the compressor, at least one of the radiator capacity control means and the evaporator capacity control means is controlled so as to reduce the capacity for a certain period of time compared to the normal operation.

  Thereby, since the differential pressure required for the expander to be driven quickly can be ensured, the time until the expander is driven can be shortened.

  The refrigeration cycle apparatus includes a bypass circuit including an expansion unit that bypasses the expander. When the compressor is started, the refrigerant flows into the bypass circuit side, and the radiator capacity control unit and the evaporator capacity At least one of the control means is controlled so as to reduce its capacity for a certain period of time compared to normal operation.

  As a result, the refrigeration cycle is not blocked when the compressor is started, so that an abnormal drop in the low pressure of the refrigeration cycle can be avoided.

  According to the operation method of the refrigeration cycle apparatus of the present invention, when the compressor is started, the differential pressure necessary for the expander to be driven quickly can be secured by controlling the capacity of the radiator and the evaporator. Therefore, the time until the expander is driven can be shortened, the power recovery loss at the time of starting the compressor can be minimized, and the reliability of the compressor can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1, the refrigeration cycle apparatus of the first embodiment includes a refrigeration cycle in which a compressor 1, a radiator 2, an expander 3, and an evaporator 5 are sequentially connected to circulate refrigerant. In addition, either a radiator capability control means 8 for controlling the capability of the radiator 2 or an evaporator capability control means 10 for controlling the capability of the evaporator 5 is provided.

  Further, the operation method of the refrigeration cycle apparatus of the first embodiment is a method of operating the refrigeration cycle apparatus, and when the compressor 1 is started, the radiator capacity control means 8 or the evaporator capacity control means 10. The start-up step for controlling one of the above capabilities to be reduced for a certain period of time as compared with that during normal operation, and the normal operation step.

  In the refrigeration cycle apparatus according to the first embodiment, such an operation method can ensure a differential pressure necessary for promptly driving the expander, and shorten the time until the expander is driven. Therefore, the power recovery loss of the expander at the time of starting the compressor can be reduced.

  Next, the refrigeration cycle apparatus of the first embodiment will be described in more detail.

The refrigeration cycle apparatus according to the first embodiment includes an expander 3, and preferably also includes a generator 4 connected to the expander 3. The expander 3 collects power by converting expansion energy of the refrigerant into mechanical energy. The expansion machine 3 converts and recovers the expansion energy of the refrigerant into mechanical energy (rotational energy), and supplies the recovered mechanical energy (rotational energy) to the generator 4 to generate electric power. The generated electric power is used, for example, as a drive source for the compressor 1. Compared with the case where the compressor 1 and the expander 3 are directly connected to each other by providing the generator 4 that generates electric power by supplying the expansion energy recovered by the expander 3, at the time of start-up Since the load on the compressor can be reduced, the power consumption can be reduced.

  Next, the radiator 2 and the radiator capacity control means 8 will be described.

  As the radiator 2, there are an air cooling type and a water cooling type.

  The radiator capacity control means 8 increases the radiator capacity, that is, the heat radiation amount of the radiator 2, and is a cooling means for the radiator 2. Cooling means includes those that exchange heat by sending air to the radiator using a radiator fan (air-cooled), and those that exchange heat using water or other fluids (such as water-cooled).

  One of the features of the first embodiment is that the capability of the radiator capability control means 8 is reduced. “Reducing the capability of the radiator capability control means 8” means reducing the cooling capability of the cooling means. By reducing the capability of the radiator capability control means 8 when the compressor 1 is started, the temperature of the radiator 2 is quickly increased. Thereby, the high voltage | pressure in the inlet_port | entrance of the expander 3 can be raised, and the expander 3 can be driven rapidly.

  Generally, the radiator capacity is expressed by the following (Equation 1).

(Equation 1) Q (W) = K (W / m ² K) × A (m ² ) × ΔT (K)
However, Q (W): radiator capacity K (W / m ² K): heat passage rate A (m ² ): radiator surface area ΔT (K): (radiator temperature−air or water temperature) .

  In order to drive the expander 3 quickly, the problem can be solved by quickly increasing the high-low pressure difference between the inlet and the outlet of the expander 3. For this purpose, the high pressure at the expander inlet may be increased or the low pressure at the expander outlet may be decreased.

In order to increase the high pressure at the expander inlet, the temperature of the radiator 2 may be increased due to the physical properties of the refrigerant. That is, the refrigeration cycle may be operated so as to increase ΔT (K) from (Equation 1), and K (W / m ² K) or A (m ² ) may be decreased. In order to decrease K (W / m ² K), it is only necessary to reduce the fan air volume in an air-cooled radiator and reduce the flow rate of a water-side circulation pump in a water-cooled radiator. Further, in order to reduce A (m ² ), when a plurality of radiators 2 a and 2 b connected in parallel as shown in FIG. 2 are provided, the radiator used by opening and closing operations of the on-off valves 301 and 302, for example. You can reduce the quantity.

  In the refrigeration cycle apparatus of the first embodiment, the radiator 2 is an air-cooled heat exchanger. The radiator capacity control means 8 includes an electric radiator fan 9 and a radiator fan controller 31 that supplies a voltage to the radiator fan 9.

  Next, the evaporator 5 and the evaporator capacity control means 10 will be described.

  The evaporator capacity control means 10 increases the heat absorption amount of the evaporator 5 and is a heating means of the evaporator 5. In this Embodiment 1, it heat-exchanges with air and the evaporator 5 by blowing with the fan 11 for evaporators.

  Another feature of the first embodiment is that the capacity of the evaporator capacity control means 10 is reduced. “Reducing the capability of the evaporator capability control means 10” means reducing the heating capability of the heating means. As described above, in order to shorten the time until the expander 3 is driven, it is necessary to quickly ensure a high-low pressure difference at the inlet / outlet of the expander 3. One method for this is to quickly reduce the low pressure at the outlet of the expander 3, that is, to quickly reduce the temperature of the evaporator 5. When the compressor 1 is started, the temperature of the evaporator 5 is quickly reduced by reducing the capacity of the evaporator capacity control means 10. Thereby, the low pressure | voltage at the exit of the expander 3 can be reduced, and the expander 3 can be driven rapidly.

  In the first embodiment, the evaporator 5 is also an air-cooled heat exchanger. The evaporator capacity control means 10 includes an electric evaporator fan 11 and an evaporator fan controller 32 that supplies a voltage to the evaporator fan 11.

  As shown in FIG. 1, the refrigeration cycle apparatus of the first embodiment desirably further includes a bypass circuit 6 that bypasses the expander 3, and has an expansion valve 7 as a decompression means in the bypass circuit 6. When the compressor 1 is started, the refrigerant is caused to flow into the bypass circuit 6 side, and at least one of the radiator capacity control means 8 and the evaporator capacity control means 10 is controlled to be reduced for a certain period of time from that during normal operation. It is desirable to do. As a result, since the refrigeration cycle is not blocked when the compressor 1 is started, it is possible to avoid an abnormal drop in the low pressure of the refrigeration cycle, and to improve the reliability of the compressor and the expansion machine when the compressor is started. Power recovery loss can be reduced at the same time.

  Further, the refrigeration cycle apparatus of the first embodiment includes a controller (control means C1) for controlling the start and stop of the compressor 1, the opening degree of the expansion valve 7, the radiator capacity control means 8, and the evaporator capacity control means 10. 211. The controller 211 has a timer 221 built therein. Although the timer 221 is provided in the controller 211 in FIG. 1, the timer 221 may be provided outside the controller 211 and connected to the controller. As will be described later, a simple and low-cost system can be constructed by using the timer 221 to shift from the control of the refrigeration cycle apparatus when the compressor 1 is started to the control during normal operation.

  Next, a change in the energy state of the refrigerant during the normal operation of the refrigeration cycle apparatus configured as described above will be described with reference to the Mollier diagram shown in FIG. 3 using a home air conditioner as an example.

  The low-temperature and low-pressure refrigerant is compressed by the operation of the compressor 1 to become a high-temperature and high-pressure refrigerant and is discharged (A → B).

  The discharged refrigerant exchanges heat with the outdoor air during the cooling operation and with the indoor air during the heating operation and flows into the expander 3 by the action of the radiator fan 9 in the radiator 2 (B → C).

  Isentropic expansion is performed in the expander 3, the pressure is reduced while generating mechanical energy, and the evaporator 5 is reached. At this time, the expansion valve 7 is fully closed by the control means C1 (C → D).

  Due to the action of the evaporator fan 11 in the evaporator 5, the refrigerant exchanged heat with the indoor air during the cooling operation and with the outdoor air during the heating operation becomes a gaseous state, and then passes through the suction pipe (not shown) to the compressor 1. (D → A).

As a result, when the radiator 2 is used as a heating source for a heater, a vending machine or the like, the coefficient of performance COP = (iB−iC) when the electric power generated by the generator 4 is used as a driving source for the compressor 1. / ((IB-iA)-(iE-iD)), and the required power of the compressor 1 can be reduced as compared with a refrigeration cycle apparatus that performs an enthalpy expansion with a conventional expansion valve, capillary tube, or the like. Efficiency is improved.

  When the evaporator 5 is used as a cooling source such as an air conditioner, a home refrigerator, a commercial refrigerator, an ice maker, or a vending machine, the electric power generated by the generator 4 is used as a drive source for the compressor 1. The coefficient of performance COP = ((iA−iE) + (iE−iD)) / ((iB−iA) − (iE−iD)), and a conventional refrigeration cycle apparatus that is enthalpy-expanded with an expansion valve or capillary tube Compared with the above, the required power of the compressor 1 is reduced and the refrigeration effect is increased, so that the efficiency is further improved.

  Next, an operation method of the refrigeration cycle apparatus of the first embodiment will be described using the flowchart of FIG. Here, the case where it is used as a heater will be described as an example.

  In the case of a heater, when an indoor temperature detection means (not shown) detects a temperature lower than a set temperature, the controller (control means C1) 211 starts the compressor 1 and starts the integration of the timer 221. In the starting step 100, a signal is sent from the control means C1 to the radiator capacity control means 8 and the evaporator capacity control means 10 to stop the radiator fan 9 and the evaporator fan 11 (or continue the stopped state) and expand. The throttle opening degree of the valve 7 is appropriately controlled, and the process proceeds to Step 110. At this time, the expansion energy is not collected by the expander 3 (the expander 3 is in a stopped state), and the refrigeration cycle operation in which the expansion valve 7 performs equal enthalpy expansion is performed.

  In step 110, the integrated value TA of the timer 221 is compared with a preset time TX1. When the integrated value TA of the timer 221 is smaller than the set time TX1, the operation returns to the start step 100 in order to avoid blockage of the refrigeration cycle, and the start step 100 is operated until the integrated value TA of the timer 221 becomes equal to or greater than the set time TX1. Maintain state. When the integrated value TA of the timer 221 is equal to or longer than the set time TX1, the routine proceeds to a normal operation step 120, where signals are sent from the control means C1 to the radiator capacity control means 8 and the evaporator capacity control means 10, and the radiator fan 9 and The evaporator fan 11 is operated, the expansion valve 7 is fully closed, the capabilities of the radiator 2 and the evaporator 5 are maximized, and the refrigerant is supplied only to the expander 3 side to recover the expansion energy. It becomes a driving state. At this time, the integrated value TA of the timer 221 is reset.

  When the normal operation step 120 is continued, for example, when an indoor temperature detection means (not shown) detects a set temperature or more, the routine proceeds to step 130 where the compressor 1, the radiator fan 9 and the evaporator fan 11 are stopped by the control means C1. To do.

  Although the case of a heater has been described above, the same applies to the case of a cooling device.

  In FIG. 5, the pressure change at the inlet / outlet of the expander 3 after the compressor 1 is started is shown by a solid line, and the differential pressure at the inlet / outlet of the expander 3 is shown by a broken line. Before the compressor 1 is started, the pressure at the inlet / outlet of the expander 3 is in a balanced state, so the differential pressure is almost 0 MPa.

When the compressor 1 is started, the radiator fan 9 and the evaporator fan 11 are stopped, so that the temperature of the radiator 2 rises quickly and the temperature of the evaporator 5 falls quickly, and as a result, expansion The inlet pressure PG of the machine 3 rises quickly, and the outlet pressure PE of the expander 3 falls quickly. Further, the differential pressure at the inlet / outlet of the expander 3 quickly increases, and when the differential pressure Δ (PG−PE) becomes the starting torque of the expander 3, that is, ΔPX which is the starting differential pressure, for example, the expander 3 is scroll expanded. In the case of a machine, a movable scroll (not shown) starts to rotate, decompressing and expanding the refrigerant, and recovering expansion energy. Therefore, the accumulated time after the compressor 1 is started (set time TX
When the relationship between 1) and the differential pressure ΔPX necessary for driving the expander 3 is obtained experimentally, as shown in the flowchart of FIG. At the same time as the motor 3 is driven, the radiator C 9 and the evaporator fan 11 are operated by the control means C 1, and the expansion valve 7 is fully closed, thereby increasing the capabilities of the radiator 2 and the evaporator 5.

  Further, when the compressor 1 is started up, the refrigerant is controlled to pass through to the bypass circuit 6 side, and supply of the refrigerant to the expander 3 side is started after sufficiently ensuring the differential pressure at the inlet / outlet of the expander 3. Thus, since the refrigeration cycle is not blocked, an abnormal drop in the low pressure of the refrigeration cycle can be avoided, and the reliability of the compressor 1 can be improved.

  In addition, although the refrigerating cycle apparatus of this Embodiment 1 was set as the structure provided with the bypass circuit 6 which bypasses the expander 3, as shown in FIG. 6, as a structure without the bypass circuit 6 which bypasses the expander 3 However, by stopping the radiator fan 9 or the evaporator fan 11 when the compressor 1 is started, the expander 3 can be driven more quickly than when the radiator fan 9 or the evaporator fan 11 is normally operated. It becomes possible.

  Although the radiator fan 9 and the evaporator fan 11 are stopped when the compressor 1 is started, the voltage applied to each fan is made smaller than that during normal operation, and the radiator 2 and the evaporator 5 are compared with those during normal operation. By reducing the amount of air passing through the compressor, it is possible to prevent an excessive increase in the compression ratio. Therefore, it is possible to reduce the power recovery loss by driving the expander 3 quickly while ensuring the reliability of the compressor 1. It becomes possible.

  In the above description, the case where the radiator fan 9 and the evaporator fan 11 are stopped has been described. It is clear that the effect is great when both of them are stopped, but when only one of them is stopped, or when only one of the airflows is reduced, the expander 3 is operated more quickly than when both are operating normally. Can be driven. Even in the refrigeration cycle apparatus having only one of the radiator fan 9 and the evaporator fan 11, the effect of the present invention can be obtained by stopping the fan or reducing the air volume.

(Embodiment 2-1)
As shown in FIG. 7, the refrigeration cycle apparatus of the present embodiment 2-1 includes a first pressure gauge 12 that detects the inlet pressure of the expander 3 in addition to the refrigeration cycle apparatus shown in FIG. 1. The second pressure gauge 13 for detecting the outlet pressure of the expander 3 is arranged in the outlet side pipe of the expander 3 in the inlet side pipe of the first pressure gauge 12 and the signals from the first pressure gauge 12 and the second pressure gauge 13. Thus, a controller (control means C2) 212 for controlling the opening degree of the expansion valve 7, the radiator capacity control means 8, and the evaporator capacity control means 10 is provided.

  In the operation method of the refrigeration cycle apparatus of the present embodiment 2-1, the first pressure gauge 12 and the second pressure gauge 13 are shifted from the startup step performed by the timer in the first embodiment to the normal operation step. This is a control method in which the difference in the pressure detected by becomes higher than a set value. With such an operation method, it is possible to determine the most accurate whether or not an appropriate differential pressure is ensured for driving the expander 3, and the power recovery is started more reliably by the expander 3, and at the same time, the radiator 2 and the ability of the evaporator 5 can be promptly shifted to the normal operation state.

  As shown in FIG. 7, the position of the first pressure gauge 12 is most suitable on the inlet side of the expander 3, but at a position from the discharge side of the compressor 1 to the outlet of the radiator 2 in the refrigeration cycle. If they can, they can play a similar role. As the arrangement position of the second pressure gauge 13, as shown in FIG. 7, piping on the outlet side of the expander 3 is most suitable, but the suction of the compressor 1 from the outlet side of the expander 3 of the refrigeration cycle. The side can play a similar role.

  Next, the operation method of the refrigeration cycle apparatus of the embodiment 2-1 will be described in detail based on the flowchart of FIG.

  For example, in the case of a heater, when an indoor temperature detection means (not shown) detects a temperature equal to or lower than a set temperature, the compressor 1 is activated by the control means C2, and the process proceeds to the activation step 200. In the starting step 200, a signal is sent from the control means C2 to the radiator capacity control means 8 and the evaporator capacity control means 10, and the radiator fan 9 and the evaporator fan 11 are stopped (or kept stopped), The throttle opening of the expansion valve 7 is appropriately controlled, and the process proceeds to step 210. At this time, the expansion energy is not collected by the expander 3 (the expander 3 is in a stopped state), and the refrigeration cycle operation in which the expansion valve 7 performs equal enthalpy expansion is performed.

  In step 210, the control means C2 calculates a difference Δ (PG−PE) between the detected value PG (input pressure) of the first pressure gauge 12 and the detected value PE (outlet pressure) of the second pressure gauge 13. The difference Δ (PG−PE) is compared with a preset differential pressure value ΔPX. When the difference Δ (PG−PE) is smaller than the differential pressure value ΔPX, the operation returns to the activation step 200 and the operation state of the activation step 200 is maintained until the difference Δ (PG−PE) becomes equal to or greater than the differential pressure value ΔPX. To do. When the difference Δ (PG−PE) becomes equal to or greater than the differential pressure value ΔPX, the routine proceeds to a normal operation step 220, and a signal is sent to the radiator capacity control means 8 and the evaporator capacity control means 10 by the control means C2, and the radiator fan 9 and the evaporator fan 11 are operated, the expansion valve 7 is fully closed, the capacity of the radiator 2 and the evaporator 5 is increased, and the refrigerant is supplied only to the expander 3 side to recover the expansion energy. It becomes a state.

  Next, when a room temperature detection means (not shown) detects a set temperature or higher, the process proceeds to step 230, and the compressor 1, the radiator fan 9, and the evaporator fan 11 are stopped by the control means C2.

  In this way, by detecting the pressure at the inlet / outlet of the expander 3, it is possible to determine the most accurate whether or not the differential pressure appropriate for driving the expander 3 is secured, and the expander is more reliably determined. At the same time that power recovery is started by 3, it is possible to quickly shift to a normal operation state in which the capabilities of the radiator 2 and the evaporator 5 are increased. As a result, it is possible to bypass the expander 3 when the compressor 1 is started up and minimize the time during which the radiator fan 9 and the evaporator fan 11 are stopped. It can be minimized.

(Embodiment 2-2)
As shown in FIG. 9, the refrigeration cycle apparatus of the present embodiment 2-2 as a modification of the embodiment 2-1 replaces the second pressure gauge 13 of the refrigeration cycle apparatus of the embodiment 2-1. In addition, a first thermometer 14 (for example, a thermistor) that detects the temperature of the evaporator 5 is provided. By moving from the startup step of the compressor 1 to the normal operation step based on the pressure value detected by the first pressure gauge 12 and the temperature detected by the first thermometer 14, an accurate and low-cost step is performed. Can be realized.

  The 1st thermometer 14 should just be a position which can detect the temperature of the evaporator 5. FIG. Specifically, it should just be installed in piping from the outlet of the expander 3 to the outlet of the evaporator 5.

  More desirably, the refrigeration cycle apparatus of the present embodiment 2-2 is a controller (control) that controls the opening degree of the radiator capacity control means 8, the evaporator capacity control means 10, and the expansion valve 7, as shown in FIG. Means C3) 213 is provided. The controller 213 is provided with expander outlet pressure calculation means for calculating a saturation pressure, that is, a pressure on the outlet side of the expander 3 from the physical properties of the refrigerant used based on the temperature detected by the first thermometer 14. Yes.

  A control method at the start-up of the compressor 1 of the refrigeration cycle apparatus configured as described above will be described based on the flowchart of FIG.

  For example, in the case of a heater, when a room temperature detecting means (not shown) detects a temperature below a set temperature, the compressor 1 is started by the controller (control means C3) 213, and the starting step 300 is performed. In the starting step 300, a signal is sent from the control means C3 to the radiator capacity control means 8 and the evaporator capacity control means 10, and the radiator fan 9 and the evaporator fan 11 are stopped and the throttle opening of the expansion valve 7 is stopped. Is appropriately controlled, and the process proceeds to step 310. Note that the outlet pressure PE 'of the expander 3 is always calculated from the detected value of the first thermometer 14 by the expander outlet pressure calculating means provided in the control means C3. At this time, the expansion energy is not collected by the expander 3 (the expander 3 is in a stopped state), and the refrigeration cycle operation in which the expansion valve 7 performs equal enthalpy expansion is performed.

  In step 310, the control means C3 determines the difference Δ (PG−) between the detected value PG (inlet pressure) of the first pressure gauge 12 and the outlet pressure PE ′ of the expander 3 predicted from the detected value of the first thermometer 14. PE ′) is calculated, and the difference Δ (PG−PE ′) is compared with a preset differential pressure value ΔPX. When the difference Δ (PG−PE ′) is smaller than the differential pressure value ΔPX, the process returns to the activation step 300 and the operation state of the activation step 300 is continued until the difference Δ (PG−PE ′) becomes larger than the differential pressure value ΔPX. To maintain. When the difference Δ (PG−PE ′) is larger than the differential pressure value ΔPX, the routine proceeds to a normal operation step 320, and a signal is sent to the radiator capacity control means 8 and the evaporator capacity control means 10 by the control means C3 to release the heat. Operating the ventilator fan 9 and the evaporator fan 11 and fully closing the expansion valve 7, raising the capabilities of the radiator 2 and the evaporator 5, and supplying the refrigerant only to the expander 3 side to recover the expansion energy, Normal operation is entered.

  Next, when an indoor temperature detection means (not shown) detects the set temperature or more, the process proceeds to step 330, and the compressor 1, the radiator fan 9, and the evaporator fan 11 are stopped by the control means C3.

  As a result, whether or not an appropriate differential pressure is secured for driving the expander 3 is determined more accurately and at a lower cost than when the outlet pressure of the expander 3 is detected by the second pressure gauge 13. It becomes possible to do.

  In addition, since the pressure difference at the inlet / outlet of the expander 3 is highly dependent on the pressure on the inlet side of the expander 3, the difference appropriate for driving the expander 3 is determined only by the detected value of the first pressure gauge 12. It is also possible to roughly determine whether the pressure is secured. In this case, it is not necessary to provide the second pressure gauge 13 or the first thermometer 14, so that it is possible to provide a more inexpensive refrigeration cycle.

(Embodiment 2-3)
As shown in FIG. 11, the refrigeration cycle apparatus of the present embodiment 2-3 as another modification of the embodiment 2-1 does not use a pressure gauge, and the radiator 2 from the discharge side of the compressor 1. It is the structure using the 2nd thermometer 15 which detects the temperature of piping which reaches the inlet of No.1. Since the inlet pressure of the expander 3 and the temperature of the piping from the discharge side of the compressor 1 to the inlet of the radiator 2 have a correlation, the temperature of the expander 3 is estimated by measuring the compressor discharge temperature. be able to.

  In Embodiment 2-3, when the second thermometer 15 detects a set temperature or higher, a signal is sent to the radiator capacity control means 8 and the evaporator capacity control means 10 by the controller (control means C4) 214, The radiator fan 9 and the evaporator fan 11 are operated, the expansion valve 7 is fully closed, the capabilities of the radiator 2 and the evaporator 5 are increased, and the refrigerant is supplied only to the expander 3 side to recover the expansion energy. The transition to the normal operation state can be realized at a lower cost.

(Embodiment 3)
FIG. 12 shows a schematic diagram of the refrigeration cycle apparatus in the third embodiment. In addition, the same code | symbol is attached | subjected about the same structure as Embodiment 1. FIG.

  In FIG. 12, the refrigeration cycle apparatus of the third embodiment is provided with an ammeter 16 for detecting the current flowing through the generator 4, and the opening degree of the expansion valve 7 and the radiator capacity control according to the signal of the ammeter 16. A controller (control means C5) 215 for controlling the means 8 and the evaporator capacity control means 10 is provided.

  The control method at the time of starting of the compressor 1 of the refrigeration cycle apparatus configured as described above will be described based on the flowchart of FIG.

  For example, in the case of a heater, when an indoor temperature detection means (not shown) detects a temperature equal to or lower than a set temperature, the compressor 1 is activated by the control means C5, and the process proceeds to the activation step 400. At the start step 400, a signal is sent from the control means C5 to the radiator capacity control means 8 and the evaporator capacity control means 10, and the radiator fan 9 and the evaporator fan 11 are stopped, and the throttle opening of the expansion valve 7 is appropriately set. Control proceeds to step 410. At this time, the expansion energy is not collected by the expander 3 (the expander 3 is in a stopped state), and the refrigeration cycle operation in which the expansion valve 7 performs equal enthalpy expansion is performed.

  In step 410, the control means C 5 detects the current value A 1 flowing through the generator 4 from the ammeter 16 and proceeds to step 420. In step 420, the current value A1 flowing through the generator 4 is compared with a preset current value AX (for example, 0 amperes). When the current value A1 flowing through the generator 4 is smaller than the preset current value AX, it is determined that the generator 4 has not started generating power, that is, the expander 3 is not driven, and flows through the generator 4. The state of the starting step 400 is maintained until the current value A1 becomes equal to or greater than a preset current value AX. If the current value A1 flowing through the generator 4 is greater than or equal to the preset current value AX, it is determined that the generator 4 has started generating power, that is, the expander 5 is being driven, and the normal operation step 430 is entered. Then, a signal is sent from the control means C5 to the radiator capacity control means 8 and the evaporator capacity control means 10, the radiator fan 9 and the evaporator fan 11 are operated, the expansion valve 7 is fully closed, and the radiator 2 and While the capacity of the evaporator 5 is increased, the refrigerant is supplied only to the expander 3 side to recover the expansion energy, and a normal operation state is obtained.

  Next, when an indoor temperature detection means (not shown) detects the set temperature or higher, the process proceeds to step 440, where the compressor 1, the radiator fan 9, and the evaporator fan 11 are stopped by the control means C5.

  In this way, by detecting the current value of the generator 4, it is possible to accurately grasp that the expander 3 has been driven, and at the same time the power recovery is started by the expander 3, the radiator 2 and the evaporator 5 Since it is possible to promptly shift to the normal operation state in which the capacity is increased, the power recovery loss of the expander 3 when the compressor 1 is started can be minimized.

(Embodiment 4)
FIG. 14 shows a schematic diagram of the refrigeration cycle apparatus in the fourth embodiment. In addition, the same code | symbol is attached | subjected about the same structure as Embodiment 1-3.

In FIG. 14, the refrigeration cycle apparatus of the fourth embodiment includes a primary side refrigerant circuit 17 and a secondary side refrigerant circuit 18. The primary refrigerant circuit 17 includes a compressor 1, a water-cooled radiator 2 that is, for example, a double pipe specification, an expander 3 that recovers power by converting expansion energy of the refrigerant into mechanical energy, and an evaporator 5. Are connected in series, and a bypass circuit 6 for bypassing the expander 3 is provided, and an expansion valve 7 is provided in the bypass circuit 6 as a pressure reducing means. Moreover, the secondary side refrigerant circuit 18 is comprised with the hot water storage tank 19, the heat radiator 2, and the circulation pump 20 for circulating water. The radiator capacity control means 8 includes a circulation pump 20 and a circulation pump control unit 33 that supplies a voltage to the circulation pump 20, and varies the amount of water flowing through the secondary side refrigerant circuit 18 by the action of the circulation pump 20. Thus, the capability control of the radiator 2 can be performed. The radiator 2 is configured such that the refrigerant flows in the primary side refrigerant circuit 17 and the secondary side refrigerant circuit 18 are opposed to each other. The hot water storage tank 19 is configured to supply tap water from the lower part and supply hot water that has become hot due to the action of the radiator 2 from the upper part to the use side circuit 21. Then, it is supplied to the bath tub 23 through the hot-water tap 22 and used. The hot water storage tank 19 is provided with a hot water storage tank water temperature thermometer 24 (for example, a thermistor) that detects the water temperature in the hot water storage tank 19, and the compressor 1 is started by a signal from the hot water storage tank water temperature thermometer 24. And a controller (control means C6) 216 having a built-in timer 226 for controlling the opening degree of the expansion valve 7, the radiator capacity control means 8, and the evaporator capacity control means 10.

  A control method at the time of starting the compressor 1 of the refrigeration cycle apparatus configured as described above will be described based on the flowchart of FIG.

  In step 500, when the hot water storage tank water temperature TB (° C.) detected by the hot water storage tank water temperature thermometer 24 detects the set temperature TL (° C.) or less, the process proceeds to step 510, and the compressor 1 is started by the control means C6, and the timer The accumulation of 226 starts. In the starting step 520, a signal is sent from the control means C6 to the radiator capacity control means 8 and the evaporator capacity control means 10, and the circulation pump 20 and the evaporator fan 11 are stopped (or the stop state is continued) and the expansion valve 7 is stopped. The throttle opening is appropriately controlled, and the process proceeds to step 530. At this time, the expansion energy is not collected by the expander 3 (the expander 3 is in a stopped state), and the refrigeration cycle operation in which the expansion valve 7 performs equal enthalpy expansion is performed.

  In step 530, the integrated value TA of the timer 226 is compared with a preset set time TX2. In step 530, until the integrated value TA of the timer 226 exceeds the set time TX2, the process returns to the start step 520, and the operation state of the start step 520 is maintained until the integrated value TA of the timer 226 becomes larger than the set time TX2. When the integrated value TA of the timer 226 becomes larger than the set time TX2, the routine proceeds to a normal operation step 540, and a signal is sent from the control means C6 to the radiator capacity control means 8 and the evaporator capacity control means 10, and the circulation pump 20 and the evaporator The fan 11 is operated, the expansion valve 7 is fully closed, the capabilities of the radiator 2 and the evaporator 5 are raised, the refrigerant is supplied only to the expander 3 side, and the expansion energy is recovered and the normal operation state is achieved. At this time, the integrated value TA of the timer 226 is reset.

  Next, when the hot water storage tank water temperature TB (° C.) detected by the hot water storage tank water temperature thermometer 24 in step 550 is detected to be equal to or higher than the set temperature TH (° C.), the process proceeds to step 560 and the control means C6 controls the compressor 1, the circulation pump 20. The evaporator fan 11 stops.

  In FIG. 16, the pressure change at the inlet / outlet of the expander 3 after the compressor 1 is started is indicated by a solid line, and the differential pressure at the inlet / outlet of the expander 3 is indicated by a broken line. Before the compressor 1 is started, the pressure at the inlet / outlet of the expander 3 is in a balanced state, so the differential pressure is almost 0 MPa.

When the compressor 1 is started, the circulation pump 20 and the evaporator fan 11 are stopped, so that the temperature of the radiator 2 rises quickly and the temperature of the evaporator 5 falls quickly. As a result, the expander 3, the inlet pressure PG of the expander 3 quickly increases, and the outlet pressure PE of the expander 3 quickly decreases. Further, the differential pressure at the inlet / outlet of the expander 3 quickly increases, and when the differential pressure Δ (PG−PE) becomes the starting torque of the expander 3, that is, ΔPX which is the starting differential pressure, for example, the expander 3 is scroll expanded. In the case of a machine, a movable scroll (not shown) starts to rotate, decompressing and expanding the refrigerant, and recovering expansion energy. Therefore, the accumulated time after the compressor 1 is started (set time TX2
) And the differential pressure ΔPX necessary for driving the expander 3 is experimentally obtained, the process proceeds from step 530 to the normal operation step 540 as shown in the flowchart of FIG. At the same time, the control means C6 operates the circulation pump 20 and the evaporator fan 11 and fully closes the expansion valve 7, thereby increasing the capabilities of the radiator 2 and the evaporator 5.

  In addition, although it was set as the structure provided with the bypass circuit 6 which bypasses the expander 3 similarly to Embodiment 1, even if it is a structure without the bypass circuit 6 which bypasses the expander 3, it is a circulation pump at the time of starting of the compressor 1 20 or the evaporator fan 11 is stopped, so that the expander 3 can be driven quickly.

  In addition, although the circulation pump 20 is stopped when the compressor 1 is started, the secondary side refrigerant circuit 18 that flows into the radiator 2 more than in the normal operation by making the voltage applied to the circulation pump 20 smaller than that in the normal operation. By reducing the amount of water, it is possible to prevent an excessive increase in the compression ratio. Therefore, it is possible to reduce the power recovery loss by driving the expander 3 quickly while ensuring the reliability of the compressor 1. Become.

  As described above, in the refrigeration cycle apparatus using hot water such as a water heater as in the first to third embodiments, the high pressure of the refrigeration cycle can be quickly increased, so that the expander 3 is driven. The pressure difference necessary for the expansion can be quickly secured and the time until the expander 3 is driven can be shortened, so that the power recovery loss of the expander 3 when the compressor 1 is started can be reduced. .

  In Embodiments 1 to 4, it is desirable to use carbon dioxide as the refrigerant. By using carbon dioxide as a refrigerant and operating the high pressure side in a supercritical state, the difference between the high and low pressures at the inlet and outlet of the expander 3 in the refrigeration cycle becomes large, so the pressure required to rotate the expander 3 The difference (torque) can be obtained more quickly, and the time for stopping the radiator fan 9 and the evaporator fan 11 when the compressor 1 is started can be shortened, so that the power recovery loss when starting the compressor 1 is minimized. It becomes possible to suppress to.

  As described above, the refrigeration cycle apparatus according to the present invention controls at least one of the radiator capacity control means and the evaporator capacity control means to reduce the capacity during normal operation for a certain period of time when the compressor is started. As a result, the power recovery loss of the expander at the time of starting the compressor can be reduced, so it can be used for a wide range of equipment such as water heaters, air conditioning and air conditioning equipment, vending machines, household refrigerators, commercial refrigerators, ice makers, etc. It can also be applied to.

Configuration diagram of a refrigeration cycle apparatus according to Embodiment 1 of the present invention. Configuration diagram of another refrigeration cycle apparatus in Embodiment 1 of the present invention Mollier diagram of the refrigeration cycle apparatus according to Embodiment 1 of the present invention. Flowchart of refrigeration cycle apparatus in Embodiment 1 of the present invention Pressure change diagram of refrigeration cycle apparatus in Embodiment 1 of the present invention Configuration diagram of another refrigeration cycle apparatus in Embodiment 1 of the present invention Configuration diagram of refrigeration cycle apparatus according to Embodiment 2-1 of the present invention Flowchart of refrigeration cycle apparatus in Embodiment 2-1 of the present invention Configuration diagram of refrigeration cycle apparatus according to Embodiment 2-2 of the present invention Flowchart of refrigeration cycle apparatus in embodiment 2-2 of the present invention Configuration diagram of a refrigeration cycle apparatus according to Embodiment 2-3 of the present invention Configuration diagram of a refrigeration cycle apparatus according to Embodiment 3 of the present invention. Flowchart of refrigeration cycle apparatus in Embodiment 3 of the present invention Configuration diagram of refrigeration cycle apparatus in Embodiment 4 of the present invention Flowchart of refrigeration cycle apparatus in Embodiment 4 of the present invention Pressure change diagram of refrigeration cycle apparatus in Embodiment 4 of the present invention Configuration diagram of conventional refrigeration cycle equipment Mollier diagram of conventional refrigeration cycle equipment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2, 2a, 2b Radiator 3 Expander 4 Generator 5 Evaporator 6 Bypass circuit 7 Expansion valve 8 Radiator capacity control means 9 Radiator fan 10 Evaporator capacity control means 11 Evaporator fan 12 First pressure Total 13 Second pressure gauge 14 First thermometer 15 Second thermometer 16 Ammeter 17 Primary side refrigerant circuit 18 Secondary side refrigerant circuit 19 Hot water storage tank 20 Circulation pump 21 Use side circuit 22 Hot water tap 23 Bath tub 24 Hot water storage tank water temperature thermometer 31 Radiator fan control unit 32 Evaporator fan control unit 33 Circulation pump control unit 100, 200, 300, 400, 520 Startup step 110, 130, 210, 230, 310, 330, 410, 420, 440 , 500, 510, 530, 550, 560 Step 120, 220, 320, 430, 540 Normal luck Step 211,212,213,214,215,216 controller 221,226 timer 301 off valve

Claims (15)

A method for operating a refrigeration cycle apparatus, comprising:
The refrigeration cycle apparatus includes:
A compressor, a radiator, an expander, and an evaporator sequentially connected to circulate the refrigerant, and further, a radiator capability control means for controlling the capability of the radiator, or the capability of the evaporator Having evaporator capacity control means for controlling
A startup step of controlling the capacity of the radiator capacity control means or the evaporator capacity control means to be reduced for a certain time from that during normal operation at the time of startup of the compressor;
A method for operating a refrigeration cycle apparatus having a normal operation step. The radiator is an air-cooled radiator,
The radiator capacity control means cools the radiator by exchanging heat with the radiator by blowing air from a fan,
The reduction of the capacity of the radiator capacity control means in the start-up step is to reduce the air volume by the fan for a certain time from the air volume in the normal operation step.
The operation method of the refrigeration cycle apparatus according to claim 1. The evaporator is an air-cooled evaporator;
The evaporator capacity control means heats the evaporator by exchanging heat with the evaporator by blowing air from a fan,
The reduction of the capacity of the evaporator capacity control means in the start-up step is to reduce the air volume by the fan for a certain time from the air volume in the normal operation step.
The operation method of the refrigeration cycle apparatus according to claim 1. The refrigeration cycle apparatus further includes a bypass circuit including an expansion valve that bypasses the expander,
In the starting step, the refrigerant is caused to flow into the bypass circuit.
The operating method of the refrigeration cycle apparatus in any one of Claims 1-3. The refrigeration cycle apparatus further includes a timer,
In the activation step, the timer is started after the compressor is activated, and when the timer reaches a set time, the normal operation step is performed.
The operating method of the refrigeration cycle apparatus in any one of Claims 1-4. The refrigeration cycle apparatus further includes a first pressure gauge on a pipe from the discharge side of the compressor to the outlet of the radiator,
In the start-up step, after the start of the compressor, when the first pressure gauge detects a set pressure value or more, the process proceeds to the normal operation step.
The operating method of the refrigeration cycle apparatus in any one of Claims 1-4. The refrigeration cycle apparatus includes a first pressure gauge on a pipe from the discharge side of the compressor to an outlet of the radiator, and a second pressure on a pipe from the outlet of the expander to the suction side of the compressor. With a meter,
In the start-up step, after the start-up of the compressor, when the difference in pressure detected by the first pressure gauge and the second pressure gauge detects a set value or more, the process proceeds to the normal operation step.
The operating method of the refrigeration cycle apparatus in any one of Claims 1-4. The refrigeration cycle apparatus further includes the first pressure gauge on a pipe from the discharge side of the compressor to an outlet of the radiator,
A first thermometer is provided in a pipe from the outlet of the expander to the outlet of the evaporator,
In the starting step, after starting the compressor, the pressure value detected by the first pressure gauge and the temperature detected by the first thermometer are shifted to the normal operation step.
The operating method of the refrigeration cycle apparatus in any one of Claims 1-4. The refrigeration cycle apparatus further includes a second thermometer that detects the temperature of a pipe from the discharge side of the compressor to the inlet of the radiator,
In the start-up step, after the start-up of the compressor, when the second thermometer detects a set temperature or higher, the process proceeds to a normal operation step.
The operating method of the refrigeration cycle apparatus in any one of Claims 1-4. The refrigeration cycle apparatus further includes a generator that generates electric power by being supplied with the expansion energy recovered by the expander.
The operation method of the refrigeration cycle apparatus according to claim 1. The refrigeration cycle apparatus further includes an ammeter that detects a current flowing through the generator,
In the start-up step, when the ammeter detects a set value or more after the start-up of the compressor, the process proceeds to the normal operation step.
The operation method of the refrigeration cycle apparatus according to claim 10. The radiator is a water-cooled radiator.
The operation method of the refrigeration cycle apparatus according to claim 1. The radiator is a water-cooled radiator,
The radiator capacity control means is composed of an electric circulation pump and a controller for driving the circulation pump,
In the startup step, the amount of water to exchange heat with the radiator is reduced for a certain time from the amount of water in the normal operation step.
The operation method of the refrigeration cycle apparatus according to claim 12. The refrigerant is carbon dioxide;
The operation method of the refrigeration cycle apparatus according to claim 1. A refrigeration cycle apparatus,
Compressor, radiator, expander, evaporator, radiator capacity control means for controlling the capacity of the radiator, or evaporation for controlling the capacity of the evaporator, which are sequentially connected to circulate the refrigerant. With the ability control means,
Furthermore, a refrigeration cycle apparatus having a controller that controls the capacity of the radiator capacity control means or the evaporator capacity control means to be reduced for a certain period of time from that during normal operation when the compressor is started.

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