JP2009228906A - Refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To protect a compressor, even if a detection value of the discharge refrigerant temperature becomes an abnormal value, in a refrigerating cycle device for controlling operation of the compressor, by using the temperature of a discharge refrigerant discharged from the compressor. <P>SOLUTION: When the detected supply hot water temperature Two of outflow hot water of a water-refrigerant heat exchanger 15 detected by a supply hot water temperature sensor 22 becomes a value higher than the detected discharge refrigerant temperature Td of the discharge refrigerant of the compressor 14 detected by a discharge refrigerant temperature sensor 21, operation of the compressor 14 is stopped. Since the actual temperature of the outflow hot water of the water-refrigerant heat exchanger 15 heated with the delivery refrigerant of the compressor 14 as a heat source does not become higher than the temperature of the delivery refrigerant of the compressor 14, the compressor 14 can be protected by surely determining that the detected hot and cold water temperature Two and the detected discharge refrigerant temperature Td are the abnormal value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus that controls the operation of a compressor using the temperature of refrigerant discharged from the compressor.

  Conventionally, Patent Document 1 is provided with a refrigerant temperature detecting means for detecting the temperature of the refrigerant discharged from the compressor (hereinafter referred to as the discharge refrigerant temperature), and the operation of the compressor is performed using the detected refrigerant discharge temperature detected. That is, a refrigeration cycle apparatus that controls the refrigerant discharge capacity of a compressor is disclosed.

Specifically, in the refrigeration cycle apparatus of Patent Document 1, during the normal operation of the cycle, the operation of the compressor is controlled so that the detected discharge refrigerant temperature detected by the refrigerant temperature detection means becomes a predetermined normal target temperature. At the start of the cycle, the operation of the compressor is controlled so that the detected discharge refrigerant temperature becomes the initial target temperature set slightly lower than the normal target temperature. Thereby, it is avoided that the discharged refrigerant temperature rises abnormally at the time of startup.
JP 2005-147437 A

  However, in the refrigeration cycle apparatus of Patent Document 1, on the premise that the detected value (detected discharged refrigerant temperature) of the discharge temperature sensor that is the refrigerant temperature detecting means is a normal value that is substantially equal to the actual discharged refrigerant temperature. Is controlling the operation. Therefore, when the detection value of the discharge temperature sensor is an abnormal value different from the actual discharge refrigerant temperature, the actual discharge refrigerant temperature may be abnormally increased.

  For example, if the detected discharge refrigerant temperature is an abnormal value lower than the actual discharge refrigerant temperature due to improper assembly of the discharge temperature sensor, improper mounting position, etc., the compressor operates so that the detected discharge refrigerant temperature becomes the target temperature. If the control is performed, the actual discharged refrigerant temperature rises abnormally. If the discharge refrigerant pressure rises abnormally as the discharge refrigerant temperature rises abnormally, it causes problems such as failure of the compressor and adverse effects on the durable life of the compressor.

  In view of the above points, the present invention provides a refrigeration cycle apparatus that controls the operation of the compressor using the temperature of the refrigerant discharged from the compressor. The purpose is to protect.

In order to achieve the above object, according to the first aspect of the present invention, the compressor (14) that compresses and discharges the refrigerant, and the amount of heat that the high-temperature refrigerant discharged from the compressor (14) has as the heat exchange target fluid. A radiator (15) for radiating heat, a decompression means (16) for decompressing and expanding the high-pressure refrigerant flowing out from the radiator (15), and an evaporator (17) for evaporating the low-pressure refrigerant decompressed by the decompression means (16) A discharge capacity changing means (14b) for changing the refrigerant discharge capacity of the compressor (14), a discharge capacity control means (20a) for controlling the operation of the discharge capacity changing means (14b), and a discharge of the compressor (14) Refrigerant temperature detection means (21) for detecting the temperature of the refrigerant, and fluid temperature detection means (22) for detecting the temperature of the heat exchange target fluid flowing out from the radiator (15),
The discharge capacity control means (20a) is configured such that the detected fluid temperature (Two) detected by the fluid temperature detection means (22) is higher than the detected discharge refrigerant temperature (Td) detected by the refrigerant temperature detection means (21). It is characterized by a refrigeration cycle apparatus that performs compressor protection control to reduce the refrigerant discharge capacity of the compressor (14) when it is turned on.

  According to this, when the detected fluid temperature (Two) is higher than the detected discharge refrigerant temperature (Td), the discharge capacity control means (20a) decreases the refrigerant discharge capacity of the compressor (14). Since the compressor protection control is performed, the compressor (14) can be protected even if the detected values of the refrigerant temperature detecting means (21) and the fluid temperature detecting means (22) become abnormal values.

  The reason is that the heat exchange target fluid is heated by using the refrigerant discharged from the compressor (14) as a heat source, so that the actual temperature of the heat exchange target fluid flowing out from the radiator (15) is discharged from the actual compressor (14). This is because it cannot be higher than the temperature of the refrigerant.

  That is, if the detected fluid temperature (Two) is higher than the detected discharge refrigerant temperature (Td), at least one of the detected values of the refrigerant temperature detecting means (21) and the fluid temperature detecting means (22) is abnormal. Means value.

  Therefore, by comparing the detected discharge refrigerant temperature (Td) with the detected fluid temperature (Two), it is easy to detect that the detected values of the refrigerant temperature detecting means (21) and the fluid temperature detecting means (22) are abnormal values. Can be judged. Furthermore, when it is determined that the detected value is an abnormal value, the refrigerant discharge capacity of the compressor (14) is reduced, so that the compressor (14) can be protected.

  In the present invention, “reducing refrigerant discharge capacity” simply means reducing the refrigerant discharge capacity to reduce the flow rate of refrigerant circulating in the cycle or changing the opening of the decompression means to lower the discharge pressure. It does not mean that the refrigerant is circulated in the cycle, but includes a state in which the refrigerant is not circulated in the cycle, that is, the operation of the cycle is substantially stopped by setting the flow rate of the refrigerant circulating in the cycle to zero.

  According to a second aspect of the present invention, in the refrigeration cycle apparatus according to the first aspect, the discharge capacity control means (20a) has a detected fluid temperature (Two) after a predetermined time has elapsed since the start of the cycle. When the temperature is equal to or lower than a predetermined temperature, start-up protection control for reducing the refrigerant discharge capacity of the compressor (14) is performed.

  According to this, as will be described in an embodiment described later, the detection values of both the refrigerant temperature detection means (21) and the fluid temperature detection means (22) are based on the actual discharge refrigerant temperature and the temperature of the heat exchange target fluid. Even when the value is low, the compressor (14) can be protected.

  According to a third aspect of the present invention, in the refrigeration cycle apparatus according to the first or second aspect, the discharge capacity control means (20a) is set in advance to the detected fluid temperature (Two) detected by the fluid temperature detection means (22). The compressor protection control is performed when the temperature to which the determined reference offset amount (α) is added is higher than the detected discharge refrigerant temperature (Td) detected by the refrigerant temperature detection means (21). Features.

  According to this, for example, even if a detection error due to an individual difference between the refrigerant temperature detection means (21) and the fluid temperature detection means (22) occurs, it is possible to appropriately determine the detection value abnormality. As a result, the compressor (14) can be appropriately protected without unnecessarily reducing the refrigerant discharge capacity of the compressor (14).

  Therefore, as in the invention described in claim 4, if the reference offset amount (α) is determined based on the measurement error amount of at least one of the refrigerant temperature detecting means (21) and the fluid temperature detecting means (22). Good. The measurement error amount is a value determined by manufacturing errors and individual differences of the refrigerant temperature detection means (21) and the fluid temperature detection means (22), and is, for example, a value that is three times the standard deviation of the measurement error. Etc. can work.

  According to a fifth aspect of the present invention, in the refrigeration cycle apparatus according to any one of the first to fourth aspects, the discharge capacity control means (20a) further includes a reference temperature at which the detected fluid temperature (Two) is predetermined. (Kte) It is characterized by performing compressor protection control when it is equal to or greater than (Kte). According to this, it is possible to prevent the detection value abnormality from being unnecessarily determined when the actual discharged refrigerant temperature is not sufficiently increased, for example, immediately after the start of the cycle.

  According to a sixth aspect of the present invention, in the refrigeration cycle apparatus according to any one of the first to fifth aspects, the discharge capacity control means (20a) is a predetermined reference time (after the cycle is started) The compressor protection control is performed after elapse of Kti). According to this, since the detected value abnormality can be determined after the actual discharge refrigerant temperature has sufficiently increased, it is possible to prevent the detected value abnormality from being unnecessarily determined.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the refrigeration cycle apparatus of the present invention is applied to a heat pump type hot water heater 10, and FIG. 1 is an overall configuration diagram of the heat pump type hot water heater 10 of the present embodiment.

  The heat pump type hot water heater 10 includes a hot water storage tank 11 that stores hot water, a water circulation circuit 12 that circulates the hot water in the hot water storage tank 11, and a heat pump cycle 13 that is a refrigeration cycle device for heating the hot water. ing.

  First, the hot water storage tank 11 is a hot water tank that is made of a metal (for example, stainless steel) having excellent corrosion resistance, has a heat insulating structure, and can keep hot hot water for a long time.

  Hot water stored in the hot water storage tank 11 is discharged from a hot water outlet 11a provided in the upper part of the hot water storage tank 11, mixed with cold water from the water at a temperature control valve (not shown), and then adjusted to a temperature in the kitchen or bath. Hot water is supplied. In addition, tap water is supplied from a water supply port 11 b provided in the lower part of the hot water storage tank 11.

  The water circulation circuit 12 is provided with an electric water pump 12a for circulating hot water. When the electric water pump 12a is operated, the hot water is supplied from an electric water pump 12a to a water-refrigerant heat exchanger 15 described later. It circulates in the order of the water passage 15a → the hot water inlet 11d at the upper part of the hot water storage tank 11 → the hot water storage tank 11 → the hot water outlet 11c at the lower part of the hot water storage tank 11 → the electric water pump 12a.

  The heat pump cycle 13 is a refrigeration cycle in which a compressor 14, a water-refrigerant heat exchanger 15, an electric expansion valve 16, an evaporator 17 and the like are sequentially connected by piping. The heat pump cycle 13 employs carbon dioxide as a refrigerant, and constitutes a supercritical refrigeration cycle in which the high-pressure refrigerant discharged from the compressor 14 has a high pressure equal to or higher than the critical pressure of the refrigerant.

  The compressor 14 sucks the refrigerant in the heat pump cycle 13 and compresses and discharges the refrigerant until the pressure becomes equal to or higher than the critical pressure. The electric compression drives the fixed displacement compressor 14a having a fixed discharge capacity by the electric motor 14b. Machine. Specifically, as the fixed capacity compressor 14a, various compression mechanisms such as a scroll compressor and a vane compressor can be employed.

  The operation (rotation speed) of the electric motor 14b is controlled by a control signal output from the control device 20 to be described later, and any type of an AC motor and a DC motor may be adopted. And the refrigerant | coolant discharge capability of the compressor 14 is changed by this rotation speed control. Accordingly, in the present embodiment, the electric motor 14b constitutes a discharge capacity changing unit.

  The refrigerant discharge port of the compressor 14 is connected to the refrigerant passage 15 b inlet side of the water-refrigerant heat exchanger 15. The water-refrigerant heat exchanger 15 is a heat exchanger configured to include a water passage 15a through which hot water passes and a refrigerant passage 15b through which high-temperature and high-pressure refrigerant discharged from the compressor 14 passes. 14 is a heat radiator that dissipates heat to the hot water supply.

  Therefore, in this embodiment, the hot water is the heat exchange target fluid. In the heat pump cycle 13 of the present embodiment, a supercritical cycle in which the pressure of the refrigerant discharged from the compressor 14 is equal to or higher than the critical pressure constitutes the refrigerant passing through the refrigerant passage 15b of the water-refrigerant heat exchanger 15. The heat is dissipated in a supercritical state without condensing.

  The inlet side of the electric expansion valve 16 is connected to the outlet side of the refrigerant passage 15 b of the water-refrigerant heat exchanger 15. The electric expansion valve 16 is a pressure reducing means for decompressing and expanding the high-pressure refrigerant flowing out from the refrigerant passage 15b, and a pressure for controlling the high-pressure side refrigerant pressure from the refrigerant discharge port of the compressor 14 to the inlet side of the electric expansion valve 16. It is also a control means.

  More specifically, the electric expansion valve 16 includes a valve body 16a that can adjust the throttle opening, and an electric actuator 16b that includes a servo motor that variably controls the throttle opening of the valve body 16a. Composed.

  An evaporator 17 is connected to the outlet side of the electric expansion valve 16. The evaporator 17 performs heat exchange between the low-pressure refrigerant decompressed by the electric expansion valve 16 and the outside air (outdoor air) blown by the blower fan 17a, thereby evaporating the low-pressure refrigerant and exerting an endothermic effect. It is a heat exchanger for use. A refrigerant suction port of the compressor 14 is connected to the refrigerant outlet side of the evaporator 17.

  Next, an outline of the electric control unit of the present embodiment will be described. The control device 20 is composed of a microcomputer and its peripheral circuits, and the output side thereof is connected to the electric water pump 12a, the electric motor 14b of the compressor 14, the electric actuator 16b of the electric expansion valve 16, the blower fan 17a and the like. And control the operation of these devices.

  Although the control device 20 is configured integrally with the above-described control means for controlling each actuator, in the present embodiment, in particular, the operation of the electric motor 14b of the compressor 14 in the control device 20 is controlled. The configuration (hardware and software) to be used is the discharge capacity control means 20a. Of course, you may comprise the discharge capability control means 20a and the control apparatus 20 separately.

  Further, on the input side of the control device 20, the refrigerant flows out of the discharge refrigerant temperature sensor 21 as discharge temperature detection means for detecting the discharge refrigerant temperature discharged from the compressor 14 and the water passage 15 a of the water-refrigerant heat exchanger 15. A sensor group such as a hot water temperature sensor 22 as fluid temperature detecting means for detecting the hot water temperature is connected.

  Other sensors include a high-pressure refrigerant temperature sensor 23 that detects the refrigerant temperature Tdo flowing out from the refrigerant passage 15b of the water-refrigerant heat exchanger 15, and heat exchange with the low-pressure refrigerant downstream of the electric expansion valve 16 in the evaporator 17. An outside air temperature sensor 24 that detects the outside air temperature Tam that is detected, an evaporation temperature sensor 25 that detects the evaporation temperature Te of the low-pressure refrigerant in the evaporator 17, and the like are connected, and detection signals from these sensor groups are input to the control device 20.

  In the present embodiment, as the discharge refrigerant temperature sensor 21, a thermistor that specifically detects the surface temperature of the refrigerant pipe on the inlet side of the refrigerant passage 15b of the water-refrigerant heat exchanger 15 is employed. A discharge temperature detecting means (for example, a thermocouple) may be employed. Further, the temperature of the refrigerant discharged from the compressor 14 may be directly detected, or a discharge temperature detecting means may be disposed inside or on the surface of the compressor 14 so that the temperature of the refrigerant discharged from the compressor 14 can be detected.

  Further, as the hot water temperature sensor 22, a thermistor for detecting the surface temperature of the hot water pipe on the outlet side of the water passage 15a of the water-refrigerant heat exchanger 15 is specifically employed. You may employ | adopt a detection means and may detect the temperature of the hot water flowed out from the water path 15a of the water-refrigerant heat exchanger 15 directly.

  Further, an operation panel 26 is connected to the input side of the control device 20, and an operation signal for hot water heater operation / stop, a hot water supply temperature setting signal for the water heater, and the like are input to the control device 20.

  Next, operation | movement of the heat pump type water heater 10 of this embodiment in said structure is demonstrated using FIG. FIG. 2 is a flowchart showing a control process executed by the control device 20. This control process starts when a hot water heater operation signal of the operation panel 26 is input to the control device 20 in a state where power is supplied to the heat pump hot water heater 10 from the outside.

  First, in step S10, flags, timers, etc. are initialized. In the next step S20, it is determined whether or not each of the above-described sensors 21 to 25 is operating. Specifically, if no detection signal is output from each sensor, it is assumed that the sensor is disconnected. If the detection signal of each sensor has a value corresponding to the applied voltage, the sensor is short-circuited (short-circuited). ) Has occurred, it is determined that each sensor is not operating.

  When it is determined in step S20 that each sensor is not operating, the operation of the heat pump type hot water heater 10 is stopped. On the other hand, if it is determined in step S20 that the sensors 21 to 25 are operating, the operation signal of the operation panel 26 and the detection signals detected by the sensor groups 21 to 25 and the like in the next step S30. Is read.

  Next, the process proceeds to step S40, and control states of various actuators, that is, control signals output to the various actuators are determined based on the operation signal and detection signal read in step S30. Specifically, control signals to be output to the electric water pump 12a, the electric motor 14b of the compressor 14, the electric actuator 16b of the electric expansion valve 16, the blower fan 17a, and the like are determined.

  For example, the control signal output to the electric water pump 12 a is determined such that the detected hot water temperature Two detected by the hot water temperature sensor 22 approaches the set hot water temperature of the operation panel 26.

  The control signal output to the electric motor 14b is determined so that the detected discharge refrigerant temperature Td detected by the discharge refrigerant temperature sensor 21 approaches a predetermined target temperature. The target temperature is a value determined based on the detected hot water temperature Two, the outside air temperature, the set hot water temperature of the operation panel 26, and the like.

  The control signal output to the electric actuator 16b is determined so that the high-pressure side refrigerant pressure approaches a predetermined target high pressure. The target high pressure is determined based on the refrigerant temperature Tdo detected by the high-pressure refrigerant temperature sensor 23 with reference to a control map stored in advance in the control device 20 so that the coefficient of performance (COP) of the cycle is substantially maximum. It is a value determined to be.

  Next, the process proceeds to step S50, and it is determined whether or not the detected hot water temperature Two detected by the hot water temperature sensor 22 is higher than the detected discharged refrigerant temperature Td detected by the discharged refrigerant temperature sensor 21. .

  In step S50, if the detected hot water temperature Two is higher than the detected discharge refrigerant temperature Td, at least one of the detected discharge refrigerant temperature Td and the detected hot water temperature Two is compressed. It determines with it being an abnormal value which has a bad influence on the durable life of the machine 14, and compressor protection control is performed in step S60.

  Specifically, in step S60, a control signal is output to the electric motor 14b so that the refrigerant discharge capacity of the compressor 14 becomes 0, and the operation of the compressor 14 is stopped. Then, the operation of the heat pump type hot water heater 10 is stopped.

  On the other hand, when the detected hot water temperature Two is not higher than the detected discharge refrigerant temperature Td in step S50, both the detected discharge refrigerant temperature Td and the detected hot water temperature Two are detected by the compressor 14. It determines with it being a normal value which does not have a bad influence on a durable life, and progresses to step S70.

  That is, step S50 of the present embodiment is a detection value for determining that at least one of the detected discharge refrigerant temperature Td and the detected hot water temperature Two is an abnormal value that adversely affects the durable life of the compressor 14. It functions as an abnormality determination means.

  In step S70, control signals are output from the control device 20 to the various actuators 12a, 14b, 16b, and 17a so that the control state determined in step S40 is obtained.

  In the next step S80, when the hot water heater stop signal from the operation panel 26 is input to the control device 20, the operation of the various actuators is stopped and the operation of the heat pump hot water heater 10 is stopped. On the other hand, when the water heater stop signal is not input, after waiting for a predetermined control period, the process returns to step S20.

  Although not shown in FIG. 2, startup protection control is also executed in the control flow of the present embodiment. Start-up protection control refers to a heat pump water heater when the detected hot water temperature Two is equal to or lower than a predetermined boiling temperature after a predetermined time has elapsed since the heat pump water heater 10 was started. 10 is control which stops the operation | movement of the heat pump type hot water heater 10 as what has not heated the hot water supply appropriately.

  Therefore, in the heat pump hot water heater 10 of the present embodiment, it is determined in step S20 that the sensors 21 to 25 and the like are operating, and in step S50, the detected discharge refrigerant temperature Td and the detected hot water temperature. During normal operation when it is determined that at least one of the two detected values is not an abnormal value that adversely affects the durable life of the compressor 14, the operation is as follows.

  The high-temperature and high-pressure refrigerant discharged from the compressor 14 flows into the refrigerant passage 15b of the water-refrigerant heat exchanger 15, and the water of the water-refrigerant heat exchanger 15 from the lower side of the hot water storage tank 11 by the electric water pump 12a. Heat exchange is performed with hot water flowing into the passage 15a. Thereby, the hot water is heated, and the heated hot water is stored above the hot water storage tank 11.

  At this time, in the heat pump cycle 13 of the present embodiment, carbon dioxide is used as the refrigerant and the supercritical refrigeration cycle is configured. Therefore, the temperature of the high-pressure refrigerant is increased as compared with the case where CFC is used as the refrigerant. be able to. As a result, in the water-refrigerant heat exchanger 15, the amount of heat that the refrigerant dissipates to the hot water supply can be increased, and the hot water temperature can be increased.

  The high-pressure refrigerant flowing out from the water-refrigerant heat exchanger 15 is decompressed and expanded by the electric expansion valve 16. The refrigerant expanded under reduced pressure by the electric expansion valve 16 flows into the evaporator 5 and absorbs heat from the outside air blown from the electric blower fan 17a to evaporate. Then, the refrigerant flowing out of the evaporator 5 is sucked into the compressor 14.

  On the other hand, if it is determined in step S50 that at least one of the detected discharge refrigerant temperature Td and the detected hot water temperature Two is an abnormal value that adversely affects the durable life of the compressor 14, Since the refrigerant discharge capability of the compressor 14 is reduced and the operation of the heat pump type hot water heater 10 is stopped by the compressor protection control, the compressor 14 can be protected.

  Here, in step S50 of the present embodiment, it is possible to determine that at least one of the detected discharge refrigerant temperature Td and the detected hot water temperature Two is an abnormal value that adversely affects the durable life of the compressor 14. Will be described.

  The hot water in the present embodiment is heated in the water-refrigerant heat exchanger 15 using the refrigerant discharged from the compressor 14 as a heat source, so that the actual hot water temperature flowing out of the water-refrigerant heat exchanger 15 is actually compressed. In principle, it cannot be higher than the discharge refrigerant temperature of the machine 14.

  Therefore, if the detected hot water temperature Two is higher than the detected discharge refrigerant temperature Td, the discharge refrigerant temperature sensor 21 outputs an abnormal value lower than the actual discharge refrigerant temperature, or hot water supply water. This means that the temperature sensor 22 outputs an abnormal value higher than the actual hot water temperature.

  When the discharge refrigerant temperature sensor 21 outputs an abnormal value lower than the actual discharge refrigerant temperature, the control device 20 unnecessarily needs the compressor 14 to bring the detected discharge refrigerant temperature Td closer to the target temperature. This increases the refrigerant discharge capacity. That is, the control device 20 unnecessarily increases the number of rotations of the electric motor 14b and adversely affects the durability life of the compressor 14.

  Therefore, if it is determined in step S50 whether or not the detected hot water temperature Two is higher than the detected discharge refrigerant temperature Td, at least one of the detected discharge refrigerant temperature Td and the detected hot water temperature Two is detected. It can be easily determined that the value is an abnormal value that adversely affects the durable life of the compressor 14.

  If the discharge refrigerant temperature sensor 21 detects a value higher than the actual discharge refrigerant temperature and the hot water supply temperature sensor 22 detects a value higher than the actual hot water supply temperature, in step S50, Any detected value of the detected discharge refrigerant temperature Td and the detected hot water temperature Two may be determined to be a value that does not adversely affect the durable life of the compressor 14.

  In this case, since the control device 20 unnecessarily decreases the refrigerant discharge capacity of the compressor 14, the actual hot water temperature is simply lower than the set hot water temperature of the operation panel 26. The durability of the compressor 14 is not adversely affected.

  If the discharge refrigerant temperature sensor 21 detects a value lower than the actual discharge refrigerant temperature, and further the hot water supply temperature sensor 22 detects a value lower than the actual hot water supply temperature, in step S50, Any detected value of the detected discharge refrigerant temperature Td and the detected hot water temperature Two may be determined to be a value that does not adversely affect the durable life of the compressor 14.

  In this case, since the value of the detected hot water temperature Two is lower than the actual hot water temperature, the system can be stopped by the above-described startup protection control. Therefore, the endurance life of the compressor 14 is not adversely affected.

  As described above, in this embodiment, the compressor 14 can be protected even if the detected values of the discharged refrigerant temperature sensor 21 and the hot water temperature sensor 22 become abnormal values.

(Second Embodiment)
In this embodiment, as shown in FIG. 3, step S50 which is a detection value abnormality determination means is changed with respect to 1st Embodiment. FIG. 3 is a flowchart corresponding to FIG. 2 of the first embodiment, and the same or equivalent parts as those of the first embodiment are denoted by the same reference numerals. The same applies to the following drawings. The structure of the other heat pump type water heater 10 is the same as that of the first embodiment.

  In step S50 of the present embodiment, a temperature obtained by adding a predetermined reference offset amount α to the detected hot water temperature Two detected by the hot water temperature sensor 22 is a detected discharged refrigerant temperature Td detected by the discharged refrigerant temperature sensor 21. It is determined whether or not the value is higher.

  In the present embodiment, the reference offset amount α is a value corresponding to the measurement error amount of the discharged refrigerant temperature sensor 21. Further, the measurement error amount means a measurement variation based on individual differences of the discharged refrigerant temperature sensors 21, and is, for example, three times the standard deviation when the same temperature is measured by a plurality of discharged refrigerant temperature sensors 21. A value or the like may be adopted.

  In the heat pump type water heater 10 of the present embodiment, not only can the same effect as in the first embodiment be obtained, but even if a detection error due to individual differences in the discharged refrigerant temperature sensor 21 occurs, it is appropriately detected in step S50. Value abnormality can be determined. Of course, the reference offset amount α may be a value corresponding to the measurement error amount of the hot water temperature sensor 22, or may be a total value of the measurement error amount of the discharge refrigerant temperature sensor 21 and the measurement error amount of the hot water temperature sensor 22. .

(Third embodiment)
In the present embodiment, step S45 is added to the first embodiment as shown in FIG. FIG. 4 is a flowchart corresponding to FIG. 2 of the first embodiment. The structure of the other heat pump type water heater 10 is the same as that of the first embodiment.

  In step S45 of this embodiment, it is determined whether or not the detected hot water temperature Two detected by the hot water temperature sensor 22 is equal to or higher than a predetermined reference temperature Kte, and the detected hot water temperature Two is equal to or higher than the reference temperature Kte. If the detected hot water temperature Two is not equal to or higher than the reference temperature Kte, the process proceeds to step S70.

  According to the heat pump type hot water heater 10 of the present embodiment, when the actual discharge refrigerant temperature is not sufficiently increased, just after the start of the heat pump type hot water heater 10, the detection value abnormality is erroneously determined. Can be prevented. The reference temperature Kte may be a value equivalent to the boiling temperature used for the start-up protection control described in the first embodiment.

(Fourth embodiment)
In the present embodiment, step S46 is added to the first embodiment as shown in FIG. FIG. 5 is a flowchart corresponding to FIG. 2 of the first embodiment. The structure of the other heat pump type water heater 10 is the same as that of the first embodiment.

  In step S46 of this embodiment, it is determined whether or not the reference time Kti is equal to or greater than a predetermined reference time Kti after the start of the cycle. If the reference time Kti is greater than or equal to the reference time Kti, the process proceeds to step S50. If not, the process proceeds to step S70. The reference time Kti is a time corresponding to a time required for the actual discharge refrigerant temperature to sufficiently increase.

  According to the heat pump type hot water heater 10 of the present embodiment, when the actual discharge refrigerant temperature is not sufficiently increased, just after the start of the heat pump type hot water heater 10, the detection value abnormality is erroneously determined. Can be prevented.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows.

  (1) In the above-described embodiment, when it is determined in step S50 that the detected discharge refrigerant temperature Td and the detected hot water supply temperature Two are abnormal values that adversely affect the durable life of the compressor 14, The operation of the heat pump type hot water heater 10 is stopped, but of course, the refrigerant discharge capacity of the compressor 14 may be reduced by a predetermined amount.

  Further, when it is determined that the detected discharge refrigerant temperature Td and the detected hot water temperature Two are abnormal values that adversely affect the durable life of the compressor 14, a warning is given to warn the user with light, sound, vibration, or the like. Means may be provided.

  (2) In the above-described embodiment, the refrigerant discharge capacity of the compressor 14 is reduced by controlling the operation of the discharge capacity changing means of the compressor 14 as the compressor protection control. However, as the compressor protection control, the fluid temperature When the detected fluid temperature detected by the detecting means is higher than the detected discharge refrigerant temperature detected by the refrigerant temperature detecting means, control for reducing the high-pressure side refrigerant pressure may be performed.

  For example, the compressor 14 can be protected by reducing the load on the compressor 14 by increasing the opening degree of the electric expansion valve 16 by a predetermined amount as compressor protection control.

  (3) In the above-described embodiment, the detected discharge refrigerant temperature Td and the detected hot water temperature Two are abnormal values that adversely affect the durable life of the compressor 14 after determining the control state of various actuators in step S40. However, the determination and the execution timing of the control are not limited to this. For example, in FIG. 2 of 1st Embodiment, you may perform between step S30 and step S40.

  (4) In the above-described embodiment, an example in which an electric compressor is employed as the compressor 14 has been described. However, the compressor 14 is not limited to this. For example, an engine-driven variable capacity compressor may be employed. In this case, the capacity control means of the variable capacity compressor becomes the discharge capacity changing means. Further, an engine-driven fixed capacity compressor may be employed. In this case, an electromagnetic clutch for intermittently transmitting power between the engine and the fixed displacement compressor serves as the discharge capacity changing means.

  (5) The heat pump cycle 13 of the above-described embodiment may be provided with an accumulator as a gas-liquid separation unit that separates the gas-liquid of the refrigerant flowing out of the evaporator 17 and stores excess refrigerant.

  (6) The heat pump cycle 13 of the above-described embodiment may be provided with an internal heat exchanger that exchanges heat between the refrigerant sucked by the compressor 14 and the refrigerant flowing out of the refrigerant passage 15b of the water-refrigerant heat exchanger 15.

It is a whole lineblock diagram of the heat pump type hot water heater of a 1st embodiment. It is a flowchart which shows the control processing of the control apparatus of 1st Embodiment. It is a flowchart which shows the control processing of the control apparatus of 2nd Embodiment. It is a flowchart which shows the control processing of the control apparatus of 3rd Embodiment. It is a flowchart which shows the control processing of the control apparatus of 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 14 Compressor 14b Electric motor 15 Water-refrigerant heat exchanger 16 Electric expansion valve 17 Evaporator 20a Discharge capability control means 21 Discharge refrigerant temperature sensor 22 Hot water temperature sensor

Claims (6)

A compressor (14) for compressing and discharging the refrigerant;
A heat radiator (15) for radiating heat of the high-temperature refrigerant discharged from the compressor (14) to the heat exchange target fluid;
Decompression means (16) for decompressing and expanding the high-pressure refrigerant flowing out of the radiator (15);
An evaporator (17) for evaporating the low-pressure refrigerant decompressed by the decompression means (16);
Discharge capacity changing means (14b) for changing the refrigerant discharge capacity of the compressor (14);
A discharge capacity control means (20a) for controlling the operation of the discharge capacity changing means (14b);
Refrigerant temperature detection means (21) for detecting the temperature of the refrigerant discharged from the compressor (14);
Fluid temperature detecting means (22) for detecting the temperature of the heat exchange target fluid flowing out of the radiator (15),
The discharge capacity control means (20a) has a detected fluid temperature (Two) detected by the fluid temperature detection means (22) based on a detected discharge refrigerant temperature (Td) detected by the refrigerant temperature detection means (21). A refrigeration cycle apparatus that performs compressor protection control for reducing the refrigerant discharge capacity of the compressor (14) when the value is high.   If the detected fluid temperature (Two) is equal to or lower than a predetermined temperature after a predetermined time has elapsed since the start of the cycle, the discharge capacity control means (20a) The refrigeration cycle apparatus according to claim 1, wherein start-up protection control is performed to reduce the refrigerant discharge capacity of   The discharge capacity control means (20a) is configured such that a temperature obtained by adding a predetermined reference offset amount (α) to the detected fluid temperature (Two) detected by the fluid temperature detection means (22) is the refrigerant temperature detection means ( The refrigeration cycle apparatus according to claim 1 or 2, wherein the compressor protection control is performed when the detected discharge refrigerant temperature (Td) detected by 21) is higher.   The reference offset amount (α) is a value determined based on a measurement error amount of at least one of the refrigerant temperature detecting means (21) and the fluid temperature detecting means (22). 3. The refrigeration cycle apparatus according to 3.   The discharge capacity control means (20a) further performs the compressor protection control when the detected fluid temperature (Two) is equal to or higher than a predetermined reference temperature (Kte). The refrigeration cycle apparatus according to any one of 1 to 4.   6. The compressor protection control according to claim 1, wherein the discharge capacity control means (20a) performs the compressor protection control after the start of a cycle and after a predetermined reference time (Kti) has elapsed. The refrigeration cycle apparatus according to any one of the above.

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