JP2013120041A - Refrigerating cycle apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating cycle apparatus which can estimate a compressor power consumption without providing a compressor current detection means, can estimate an ejection pressure with high precision and can be provided at a low cost.SOLUTION: The refrigerating cycle apparatus includes: an electric source current detection means for detecting the current value of an electric source supplied to the refrigerating cycle apparatus as the compressor power consumption estimation means for estimating power consumed by a compressor; an electric source voltage detection means for calculating the voltage of the electric source from a DC voltage provided by rectifying and smoothing the voltage of the electric source; a power factor estimation means for calculating a power factor from the value detected by the electric source current detection means and the electric source voltage detection means; and an ejection pressure estimation means for estimating the pressure of coolant ejected from the compressor by using an evaporator temperature, an external temperature, the number of rotations of the compressor, and power consumption of the compressor, wherein the compressor or an expansion valve is controlled based on an ejection pressure estimated by the ejection pressure estimation means.

Description

  The present invention relates to a refrigeration cycle apparatus using a substance that can be supercritical on the high-pressure side as a refrigerant.

  FIG. 6 is a configuration diagram of a refrigeration cycle apparatus mounted on a conventional heat pump water heater. The refrigerant circuit 5 is configured by connecting the compressor 1, the radiator 2, the expansion valve 3, and the evaporator 4 in the order of a ring. The incoming water pipe 6 and the outgoing hot water pipe 7 are connected to the radiator 2. The pressure switch 8 is connected to a branch pipe 10 branched from the refrigerant circuit 5 between the compressor 1 and the radiator 2. The switch means 9 is provided on an AC power supply circuit supplied to the refrigeration cycle apparatus (see, for example, Patent Document 1).

  The high-pressure refrigerant discharged from the compressor 1 is supplied to the radiator 2, and heat is exchanged with water in the radiator 2 to dissipate heat and then supplied to the expansion valve 3. After being depressurized by the expansion valve 3, it is supplied to the evaporator 4, absorbs heat, and then sucked into the compressor 1. In a refrigeration cycle apparatus (for example, a refrigeration cycle apparatus mounted on an air conditioner using R410A as a refrigerant) in which the discharge pressure of the refrigerant discharged from the compressor 1 is equal to or lower than the critical pressure, the discharge pressure is determined from the condensation temperature of the condenser. In a refrigeration cycle apparatus (for example, a refrigeration cycle apparatus mounted on a heat pump water heater that uses carbon dioxide as a refrigerant) in which the discharge pressure exceeds the critical pressure, although an abnormal increase in the discharge pressure can be recognized, It is difficult to estimate the discharge pressure from the temperature of the radiator 2. Therefore, the pressure switch 8 operates when the pressure of the refrigerant discharged from the compressor 1 exceeds a preset threshold value, and the switch means 9 switches from on to off in accordance with the operation of the pressure switch 8. Shut off the AC power circuit. By providing these, even in the refrigeration cycle apparatus in which the refrigerant is in a supercritical state on the high-pressure side, it is possible to recognize an abnormal increase in discharge pressure, stop the operation of the refrigeration cycle apparatus, and increase the discharge pressure abnormally. Play a role to prevent.

  FIG. 7 is a configuration diagram of a refrigeration cycle apparatus mounted on another conventional heat pump water heater. Discharge pressure estimation means 11 for estimating the discharge pressure from the operating state of the refrigeration cycle apparatus, compressor current detection means 12 for detecting the current value flowing to the motor of the compressor 1, and compressor rotation speed for detecting the rotation speed of the motor A detection means 13, a radiator outlet temperature detection means 14 for detecting the temperature of the refrigerant sent from the radiator 2 to the expansion valve 3, and an evaporator temperature detection means 15 for detecting the refrigerant temperature in the evaporator 4, Based on the values detected by the discharge pressure estimation means 11 at least by the compressor current detection means 12, the compressor rotation speed detection means 13, the radiator outlet temperature detection means 14, and the evaporator temperature detection means 15, the discharge pressure estimation means 11 The discharge pressure is estimated from the correlation between the power consumption of the motor and the discharge pressure recorded in advance (see, for example, Patent Document 2).

  By providing the discharge pressure estimating means 11, it is possible to recognize the discharge pressure without providing a pressure detecting means such as a pressure switch or a pressure sensor.

Japanese Patent No. 4222227 JP 2010-2090 A

However, in the refrigeration cycle apparatus described in Patent Document 1, the pressure switch 8 and the branch pipe 10 rise to substantially the same temperature as the refrigerant discharged from the compressor 1 (about 90 to 120 ° C.). There was a problem that heat leakage from the part occurred and the energy consumption efficiency of the refrigeration cycle apparatus was reduced.

  In addition, the refrigeration cycle apparatus described in Patent Document 2 includes discharge pressure estimation means 11 that estimates the discharge pressure from the operating state of the refrigeration cycle apparatus without including pressure detection means such as a pressure switch and a pressure sensor. Although there is no heat leakage due to the provision of the pressure detection means, it is necessary to have the compressor current detection means 12 used for calculating the compressor power, and there is a problem that leads to an increase in the cost of the refrigeration cycle apparatus.

  The present invention solves the above-mentioned conventional problems, and is a refrigeration cycle apparatus that can estimate the discharge pressure of a compressor with an inexpensive configuration without including pressure detection means such as a pressure sensor and a pressure switch and compressor current detection means. The purpose is to provide.

  In order to solve the conventional problem, a refrigeration cycle apparatus according to the present invention includes a refrigerant circuit in which at least a compressor, a radiator, an expansion valve, and an evaporator are connected in an annular shape to circulate refrigerant, and circulates through the evaporator. In the refrigeration cycle apparatus, comprising the evaporator temperature detection means for detecting the temperature of the refrigerant, the outside temperature detection means for detecting the outside air temperature, and the compressor rotation speed detection means for detecting the rotation speed of the compressor, the compression As a compressor power consumption estimation means for estimating the power consumed by the compressor, a power supply current detection means for detecting a current value of a power supply supplied to the refrigeration cycle apparatus, and a DC voltage obtained by rectifying and smoothing the voltage of the power supply Power supply voltage detection means for calculating, power source current detection means, and power factor estimation means for calculating a power factor from the value detected by the power supply voltage detection means, the evaporator temperature and the outside air temperature, A discharge pressure estimating means for estimating the pressure of the refrigerant discharged from the compressor using the compressor rotation speed and the compressor power consumption, and the compression based on the discharge pressure estimated by the discharge pressure estimating means Or operating the expansion valve.

  This makes it possible to estimate the compressor power consumption without the need to provide a compressor current detection means, and therefore to accurately estimate the discharge pressure, correctly recognize the occurrence of an abnormal increase in the discharge pressure, and The operation of the apparatus can be stopped to prevent the operation at an abnormal pressure exceeding the design pressure.

  Detected by the power supply current detection means for detecting the power supply current value, the power supply voltage detection means for calculating the power supply voltage value, the power supply current detection means and the power supply voltage detection means as the power consumption calculation means used for estimating the discharge pressure By calculating the discharge pressure of the compressor from the power factor estimating means for calculating the power factor from the measured value, it is not necessary to have a pressure switch, a pressure sensor, and a compressor current detecting means, and the compressor is inexpensive and accurate. It is possible to estimate the discharge pressure.

Configuration diagram of a refrigeration cycle apparatus according to Embodiment 1 of the present invention. Correlation diagram of power factor with respect to power supply current value and power supply voltage value in the first embodiment Correlation diagram of blower power consumption with respect to blower rotation speed in the first embodiment Correlation diagram of control unit power consumption with respect to power supply current value in the first embodiment Correlation diagram of estimated discharge pressure against compressor power consumption and evaporator temperature in the first embodiment Configuration diagram of conventional refrigeration cycle equipment Configuration diagram of another conventional refrigeration cycle apparatus

  A first invention includes a refrigerant circuit in which at least a compressor, a radiator, an expansion valve, and an evaporator are connected in an annular shape so that the refrigerant circulates, and an evaporator temperature detection unit that detects the temperature of the refrigerant circulating in the evaporator. Compressor consumption for estimating electric power consumed by the compressor in a refrigeration cycle apparatus comprising an outside air temperature detecting means for detecting the outside air temperature and a compressor rotation speed detecting means for detecting the rotation speed of the compressor As power estimation means, power supply current detection means for detecting the current value of the power supplied to the refrigeration cycle apparatus, power supply voltage detection means for calculating the voltage of the power supply from a rectified and smoothed DC voltage, and the power supply current detection And a power factor estimating means for calculating a power factor from a value detected by the power supply voltage detecting means, using the evaporator temperature, the outside air temperature, the compressor rotational speed, and the compressor power consumption. The A discharge pressure estimating means for estimating the pressure of the refrigerant discharged from the compressor, and controlling the compressor or the expansion valve based on the discharge pressure estimated by the discharge pressure estimating means to perform compression. It is possible to estimate the compressor power consumption without the need to provide a machine current detection means, and therefore to accurately estimate the discharge pressure, correctly recognize the occurrence of an abnormal increase in the discharge pressure, and operate the refrigeration cycle apparatus. It can be stopped and operation at abnormal pressure exceeding the design pressure can be prevented.

  According to a second invention, in particular, in the first invention, the power supply voltage value detected by the power supply voltage detecting means can be calculated with high accuracy by performing the power supply voltage value before the operation of the compressor. Become.

  The third invention is the blower for promoting the evaporation of refrigerant in the evaporator, the blower rotational speed detecting means for detecting the rotational speed of the blower, and the detected rotational speed, particularly in the first or second invention. Moreover, it is provided with a blower power consumption estimation means for calculating the power consumed by the blower, and the compressor power consumption value is a value obtained by subtracting the blower power consumption value, thereby reducing the compressor power consumption. It is possible to calculate with higher accuracy and to estimate the discharge pressure with high accuracy.

  In a fourth aspect of the invention, in particular, in any one of the first to third aspects, at least the control unit that controls the compressor, the expansion valve, the blower, and the like, and the power consumed by the control unit A control unit power consumption estimation unit that calculates from the current value detected by the current detection unit, wherein the compressor power consumption value is a value obtained by subtracting the control unit power consumption value; Can be calculated more accurately, and the discharge pressure can be estimated with high accuracy.

  In a fifth aspect of the invention, in particular, in any one of the first to fourth aspects of the invention, the compressor or the pressure reducing mechanism is controlled so that the discharge pressure estimated by the discharge pressure estimation means matches a preset target value. Thus, the refrigeration cycle apparatus can be operated with high energy efficiency.

  In a sixth aspect of the invention, in particular, in any one of the first to fifth aspects of the invention, when the discharge pressure estimated by the discharge pressure estimating means exceeds a preset threshold value, the compressor or the pressure reducing mechanism is controlled to operate. By doing so, an abnormal increase in the discharge pressure of the refrigeration cycle apparatus can be prevented.

  In the seventh invention, in particular, in any one of the first to sixth inventions, when the compressor is driven, the high pressure of the refrigerant circuit is operated at a supercritical pressure, so that the discharge pressure can be estimated with high accuracy. .

  In the eighth invention, in particular, by using carbon dioxide as the refrigerant, there is no danger of combustion even if the refrigerant leaks, and the refrigeration cycle apparatus can be operated with peace of mind.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of a refrigeration cycle apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the control unit 18 includes a power supply current detection unit 19, a power supply voltage detection unit 20, a power factor estimation unit 21, a blower rotation speed detection unit 22, a blower power consumption estimation unit 23, and a control unit power consumption estimation. Means 24, compressor power consumption estimation means 25, compressor rotation speed detection means 28, expansion valve control means 26, compressor control means 27, and discharge pressure estimation means 11.

  Further, a compressor 1, a radiator 2, an expansion valve 3 and an evaporator 4 are connected in an annular shape on the refrigerant circuit 5 side, and carbon dioxide is circulated as a refrigerant, and a water inlet pipe 6, a hot water outlet pipe 7, an evaporator. A blower 17 for evaporating the refrigerant inside, an evaporator temperature detecting means 15, an outside air temperature detecting means 16, and a discharge temperature detecting means 29 are provided. The evaporator temperature detecting means 15 is provided on the pipe surface of the refrigerant inlet of the evaporator 4. The outside air temperature detection means 16 is provided on the windward side of the evaporator 4 so as to detect the temperature of the air introduced into the evaporator 4. The discharge temperature detecting means 29 is provided on the surface of the pipe for introducing the refrigerant from the compressor 1 to the radiator 2.

  About the refrigerating-cycle apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the refrigeration cycle apparatus is in operation, the rotation speed fc of the compressor 1 is determined by the compressor control means 27 to a preset rotation speed so that the heating capacity in the radiator 2 becomes a target value. . As a result, the refrigeration cycle apparatus can be operated by selecting a compressor rotational speed that satisfies the required heating capacity in accordance with the operating conditions.

  The opening degree of the expansion valve 3 is controlled and determined by the expansion valve control means 26 so that the discharge temperature Td detected by the discharge temperature detection means 29 coincides with a preset target value. By doing so, the expansion valve 3 can be controlled and operated so that the energy consumption efficiency of the refrigeration cycle apparatus is maximized. The expansion valve control means 26 controls the expansion valve 3 so that the superheat degree of the refrigerant increases as the outside air temperature increases, so that the superheat degree of the refrigerant sucked into the compressor 1 has a correlation with the outside air temperature Tat. .

  The power supply current detection means 19 detects the total current value IHP supplied to the refrigeration cycle apparatus, and sends the detected current value IHP to the compressor power consumption estimation means 25 as a signal.

  The power supply voltage detection means 20 detects the power supply voltage value VHP from the value calculated from the DC voltage of the rectifying / smoothing circuit that rectifies and smoothes the power supply voltage before the compressor 1 is operated, and compresses the detected power supply voltage value VHP as a signal. To the power consumption estimation means 25. However, detection and updating of the power supply voltage value VHP value are not performed during operation so as not to be affected by the power factor correction circuit or the like.

  FIG. 2 is a correlation diagram of the power factor with respect to the power supply current value and the power supply voltage value. The power factor estimating means 21 calculates a power factor from the current value IHP detected by the power supply current detecting means 19 and the voltage value VHP detected by the power supply voltage detecting means 20 from FIG. The rate value PFHP is sent to the compressor power consumption estimation means 25 as a signal.

  The evaporator temperature detecting means 15 detects the temperature of the pipe surface at the refrigerant side inlet of the evaporator 4 and sends the refrigerant temperature Te in the evaporator 4 to the discharge pressure estimating means 11 as a signal. Since the evaporator temperature detection means 15 detects the temperature of the pipe surface, when the operation of the refrigeration cycle apparatus is in a substantially steady state, the detected evaporator temperature Te and the refrigerant temperature inside the pipe are substantially the same. .

  The outside air temperature detection means 16 detects the temperature of the air introduced into the evaporator 4 and sends the outside air temperature Tat as a signal to the discharge pressure estimation means 11.

  The compressor rotation speed detection means 28 detects the rotation speed of the compressor and sends the compressor rotation speed fHZ to the discharge pressure estimation means 11 as a signal.

  FIG. 3 is a correlation diagram of blower power consumption with respect to blower rotation speed. The blower power consumption estimation means 23 calculates the blower power consumption from the predetermined FIG. 3 based on the rotation speed FMrpm detected by the blower rotation speed detection means 22 for detecting the rotation speed of the blower 17, and the blower power consumption Wf. Is sent to the compressor power consumption estimation means 25 as a signal.

  FIG. 4 is a correlation diagram of the control unit power consumption with respect to the power supply current value. The control unit power consumption estimation unit 24 calculates the control unit power consumption from the predetermined power supply current value IHP detected by the power supply current detection unit 19 from FIG. 4, and uses the control unit power consumption Wp as a signal as a compressor. This is sent to the power consumption estimation means 25.

  The compressor power consumption estimation means 25 sends the power supply current value IHP sent as a signal from the power supply current detection means 19, the power supply voltage value VHP sent as a signal from the power supply voltage detection means 20, and the power factor estimation means 21 sends it as a signal. The refrigeration cycle power consumption WHP is calculated from the obtained power factor value PFHP. Further, the blower power consumption value Wf sent as a signal from the blower power consumption estimation means 23 and the control unit power consumption Wp sent as a signal from the control section power consumption estimation means 24 are subtracted from the refrigeration cycle power consumption WHP, and the compressor The power consumption Wc is calculated, and the calculated compressor power consumption Wc is sent to the discharge pressure estimation means 11 as a signal.

  FIG. 5 is a correlation diagram of the estimated discharge pressure with respect to the compressor power consumption and the evaporator temperature. The discharge pressure estimating means 11 is determined in advance by the compressor power consumption Wc sent as a signal from the compressor power consumption estimating means 25 and the evaporator temperature Te sent as a signal from the evaporator temperature detecting means 15. The discharge pressure Pd is estimated using FIG. The outside air temperature Tat sent as a signal from the outside air temperature detection means 16 and the compressor rotation speed fHZ sent as a signal from the compressor rotation speed detection means 28 influence the outside air temperature and the compressor rotation speed fluctuation. By correcting the discharge pressure Pd, the detection accuracy can be further improved.

  When the discharge pressure Pd estimated by the discharge pressure estimating means 11 as described above exceeds a preset threshold value P0, the compressor control means 27 determines that an abnormal increase in pressure has occurred in the refrigeration cycle apparatus and operates. To stop.

  As described above, in the present embodiment, it is possible to estimate the compressor power consumption Wc without the need for providing the compressor current detection means, and hence it is possible to estimate the discharge pressure with high accuracy. Then, it is possible to correctly recognize the occurrence of the abnormal increase in the discharge pressure, stop the operation of the refrigeration cycle apparatus, and prevent the operation at an abnormal pressure exceeding the design pressure.

  The compressor control means 27 of the present embodiment reduces the rotational speed of the compressor 1 when the discharge pressure Pd estimated by the discharge pressure estimation means 11 exceeds a preset threshold value P0. Also good. By doing in this way, even in a transient state such as immediately after the start of the refrigeration cycle apparatus, the occurrence of an abnormal increase in the pressure of the refrigeration cycle apparatus is correctly determined, and the number of revolutions of the compressor 1 is decreased to discharge exceeding the design pressure. An abnormal increase in pressure can be suppressed.

The expansion valve control means 26 of the present embodiment increases the opening of the expansion valve 3 when the discharge pressure Pd estimated by the discharge pressure estimation means 11 exceeds a preset threshold value P0. Also good. By doing so, even in a transient state such as immediately after the start of the refrigeration cycle apparatus, it is correctly determined that the pressure has risen abnormally, the opening of the expansion valve 3 is increased, and the discharge pressure exceeds the design pressure. Can be suppressed.

  As described above, the refrigeration cycle apparatus according to the present invention can estimate the discharge pressure from the compressor including the supercritical state without including a pressure sensor, a pressure switch, or the like, and the heat pump water heater or hot water heater In a refrigeration cycle apparatus that uses a refrigerant in a supercritical state on the high-pressure side, the energy efficiency can be improved and the apparatus can be applied to a protective device.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Radiator 3 Expansion valve 4 Evaporator 5 Refrigerant circuit 6 Inlet piping 7 Outlet piping 8 Pressure switch 9 Switch means 10 Branch piping 11 Discharge pressure estimation means 12 Compressor current detection means 13 Compressor rotation speed detection means 14 Heat radiation Outlet temperature detection means 15 Evaporator temperature detection means 16 Outside air temperature detection means 17 Blower 18 Controller 19 Power supply current detection means 20 Power supply voltage detection means 21 Power factor estimation means 22 Blower rotational speed detection means 23 Blower consumption power estimation means 24 Control Power consumption estimation means 25 compressor power consumption estimation means 26 expansion valve control means 27 compressor control means 28 compressor rotation speed detection means 29 discharge temperature detection means

Claims (8)

A refrigerant circuit in which at least a compressor, a radiator, an expansion valve, and an evaporator are connected in an annular shape to circulate the refrigerant, an evaporator temperature detecting means for detecting the temperature of the refrigerant circulating in the evaporator, and an outside air temperature are detected. In a refrigeration cycle apparatus comprising an outside air temperature detection means and a compressor rotation speed detection means for detecting the rotation speed of the compressor, as the compressor power consumption estimation means for estimating the power consumed by the compressor, Power supply current detection means for detecting the current value of the power supplied to the refrigeration cycle apparatus, power supply voltage detection means for calculating the power supply voltage from a rectified and smoothed DC voltage, the power supply current detection means, and the power supply voltage detection Power factor estimating means for calculating a power factor from the value detected by the means, from the compressor using the evaporator temperature, the outside air temperature, the compressor rotational speed, and the compressor power consumption Comprising a discharge pressure estimation means for estimating a pressure of the refrigerant issued, the refrigeration cycle device, characterized in that to operate by controlling the compressor or the expansion valve based on the discharge pressure estimated by said discharge pressure estimation means. The refrigeration cycle apparatus according to claim 1, wherein the power supply voltage value detected by the power supply voltage detection means is performed before the operation of the compressor. The blower power consumption for calculating the power consumed by the blower from the blower for promoting the evaporation of the refrigerant in the evaporator, the blower revolution number detecting means for detecting the revolution number of the blower, and the detected revolution number. The refrigeration cycle apparatus according to claim 1, further comprising: an estimation unit, wherein the compressor power consumption value is a value obtained by subtracting the blower power consumption value. A control unit that controls at least the compressor, the expansion valve, the blower, and the like; and a control unit power consumption estimation unit that calculates power consumed by the control unit from a current value detected by the power source current detection unit. The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the compressor power consumption value is a value obtained by subtracting the control unit power consumption value. 5. The operation according to claim 1, wherein the compressor or the pressure reducing mechanism is controlled to operate so that the discharge pressure estimated by the discharge pressure estimating means matches a preset target value. The refrigeration cycle apparatus described. The refrigeration according to any one of claims 1 to 5, wherein when the discharge pressure estimated by the discharge pressure estimation means exceeds a preset threshold value, the compressor or the pressure reducing mechanism is controlled to operate. Cycle equipment. The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein when the compressor is driven, the refrigerant circuit is operated at a supercritical pressure. The refrigeration cycle apparatus according to claim 7, wherein carbon dioxide is used as the refrigerant.