JP2010071603A - Heat pump water heater - Google Patents

Abstract

To provide a long-term highly reliable and low-cost heat pump water heater by detecting an abnormality and stopping a compressor without using a pressure switch or a discharge pressure detecting means.
A heat pump (1) formed by connecting a compressor (2), a radiator (3), a decompression means (4) and an air heat exchanger (5), a hot water storage tank (8) for storing hot water heated by the radiator (2), Current value detecting means 34 for detecting a current value flowing through the compressor 2, and when the current value becomes a predetermined value or more within a predetermined time after the start-up of the compressor 2, the operation of the compressor 2 is performed. In a heat pump water heater characterized by having a configuration that stops the operation, the compressor is stopped by detecting an abnormality without using a pressure switch or a discharge pressure detection means, thereby achieving high reliability and low performance over a long period of time. Cost heat pump water heater can be provided.
[Selection] Figure 1

Description

  The present invention relates to a heat pump water heater that supplies hot water by storing heated hot water in a hot water storage tank.

  FIG. 2 shows a conventional heat pump water heater (see, for example, Patent Document 1 and Patent Document 2).

  As shown in FIG. 2, the heat pump water heater includes a hot water storage tank 8 and heating means using the heat pump 1, and is connected to the heat pump 1 from the lower part of the hot water storage tank 8 with a boiling pipe 9. Connected to the top. The heat pump 1 is configured by connecting a compressor 2, a radiator 3, a decompression unit 4, and an air heat exchanger 5 in an annular shape.

  In the boiling operation, the high-temperature and high-pressure gas refrigerant pressurized by the compressor 2 of the heat pump 1 is sent to the radiator 3 to exchange heat with the cold water at the bottom of the hot water storage tank 8 conveyed by the boiling pump 7. It becomes a low-temperature refrigerant. Then, the refrigerant radiated to the cold water by the radiator 3 is decompressed by the decompression device 4 and becomes a two-phase refrigerant, which is sent to the air heat exchanger 5 to exchange heat with the atmosphere to become a low-temperature gas refrigerant and circulate to the compressor 2. .

  On the other hand, the cold water at the bottom of the hot water storage tank 8 is conveyed to the radiator 3 by the boiling pump 7 and absorbs the heat of the refrigerant to become hot water, and is sent to the upper portion of the hot water tank through the boiling pipe 9. . At this time, the hot water is hardly mixed with water due to the density difference, and the hot water is stacked from the upper part of the hot water storage tank 8 so that the hot water is accumulated in the hot water storage tank 8.

  At this time, when the discharge pressure of the refrigerant by the compressor 2 in the heat pump 1 rises abnormally, the driving of the compressor 2 is stopped.

For example, when an abnormality occurs in the refrigeration cycle of the heat pump and the discharge pressure of the compressor exceeds a certain level, a stop means 29 that stops the compressor 2 in response to turning off the pressure switch 10 is connected to the AC power supply line to the compressor. The configuration used is proposed. Further, there is provided stop means for stopping the compressor 2 when the discharge pressure is detected by the discharge pressure detection means 10 to detect an abnormality in the refrigeration cycle and when it exceeds a predetermined value.
JP 2005-249293 A JP 2008-14511 A

  However, in the above-described conventional configuration, the pressure switch or the discharge pressure detecting means for detecting the abnormality is repeatedly started and stopped of the heat pump. For example, in the heat pump using carbon dioxide gas as the refrigerant, the pressure at the time of stopping Since the operation is repeated from about 4 MPa to about 10 MPa at the time of operation, if the heat pump water heater is used for many years, the detection accuracy of the sensor will be deviated. The water heater stops and cannot fully function.

  Or there was a problem in terms of long-term reliability, such as the compressor not stopping despite the abnormality and causing the heat pump water heater to fail.

  Further, the pressure switch or the discharge pressure detecting means is an expensive part, which increases the cost.

  An object of the present invention is to provide a long-term reliability improvement and low-cost heat pump water heater by detecting an abnormality and stopping the compressor without using a pressure switch or a discharge pressure detecting means. It is an object.

  In order to solve the above problems, the present invention provides a heat pump formed by connecting a compressor, a radiator, a decompression unit, and an air heat exchanger, a hot water storage tank for storing hot water heated by the radiator, A current value detecting means for detecting a current value flowing through the compressor, and the operation of the compressor is stopped when the current value becomes a predetermined value or more within a predetermined time after the start of the compressor. In the heat pump water heater characterized by the above, when the decompression means is normal, after the compressor is started, an appropriate high pressure is maintained by the operation of the decompression means. While the pressure state becomes approximately constant, the degree of increase slows down, but there is an abnormality in the decompression means, and in the closed state, the current value continues to increase as the high pressure increases immediately after the compressor starts, Pressure reducing valve is positive To indicate the value that exceeds the current value of a state, it detects an abnormality of the pressure reducing means by the current value detecting means.

  ADVANTAGE OF THE INVENTION According to this invention, the heat pump water heater which can detect abnormality and can stop a compressor operation without using a pressure switch or a discharge pressure detection means can be provided.

  A first invention includes a heat pump formed by connecting a compressor, a radiator, a decompression unit, and an air heat exchanger, a hot water storage tank for storing hot water heated by the radiator, and a current flowing through the compressor And a current value detecting means for detecting a value, and the operation of the compressor is stopped when the current value becomes a predetermined value or more within a predetermined time after the start of the compressor. If the pressure reducing means is normal in the heat pump water heater, after starting up the compressor, it is maintained at an appropriate high pressure by the operation of the pressure reducing means, so the current value rise is approximately constant at each temperature and pressure state of the refrigeration cycle However, if the decompression means is abnormal and is in a closed state, the current value continues to rise as the high pressure rises immediately after the compressor starts, and the decompression valve is normal. State current value exceeded To indicate that value, it detects an abnormality of the pressure reducing means by the current value detecting means.

  The second invention is a heat pump formed by connecting a compressor, a radiator, a pressure reducing means, and an air heat exchanger, a hot water storage tank for storing hot water heated by the radiator, and the heat radiator. An inlet water temperature detecting means for detecting an incoming water temperature; and a hot water temperature detecting means for detecting a hot water temperature flowing out of the radiator; and after a predetermined time after the start of the compressor, The heat pump water heater is configured to stop the operation of the compressor when the temperature difference of the temperature is equal to or less than a predetermined value. During the operation of the heat pump, the water enters the hot water storage tank and the hot water from the hot water storage tank. If the hot water is circulated normally, the water will receive heat from the heat pump and the hot water temperature will rise compared to the incoming water temperature. However, if the water circulation is abnormal, especially if it does not circulate, there will be almost no temperature difference. For entering It is possible to detect the abnormality due to the temperature difference between the temperature and the tapping temperature.

A third invention includes a heat pump formed by connecting a compressor, a radiator, a decompression unit, and an air heat exchanger, a hot water storage tank for storing hot water heated by the radiator, and a compressor discharge of the heat pump. A discharge temperature detection means for detecting temperature; and a tapping temperature detection means for detecting a tapping temperature flowing out of the radiator; a temperature between the discharge temperature and the tapping temperature after a predetermined time after the compressor is started. The heat pump water heater is configured to stop the operation of the compressor when the difference is equal to or greater than a predetermined value. During the operation of the heat pump, the water enters the hot water storage tank and the hot water discharge from the hot water storage tank. If the water is circulated normally, the water will receive heat from the heat pump and the tapping temperature will rise.However, if the water circulates abnormally, especially if it does not circulate, the heat generated by the heat pump will be transferred to the water. No reason, despite the discharge temperature is high, the hot water temperature does not rise, it is possible to detect an abnormality due to the temperature difference between the temperature difference between the discharge temperature and the tapping temperature.

  The fourth invention is characterized in that, in any one of the first to third inventions, the refrigerant flowing through the radiator is pressurized to a supercritical pressure during compressor operation, and flows through the radiator. Since the refrigerant is pressurized to supercritical pressure by the compressor, it will not condense even if the heat is taken away by the radiator and the temperature drops, and a temperature difference is formed between the refrigerant and water throughout the radiator. It becomes easy and heat exchange efficiency can be made high.

  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)
Hereinafter, the water heater according to Embodiment 1 will be described with reference to the drawings. FIG. 1 is a circuit diagram of a heat pump water heater in an embodiment of the present invention.

  The outline of the apparatus includes a hot water storage tank 8 in which low temperature hot water and high temperature hot water are stored in a layered state, and a heat pump 1 that is a heating source for heating the hot water. Water is heated and boiled for hot water storage and used for hot water supply.

  First, the configuration of the heat pump 1 as a heating source will be described with reference to FIG.

  The heat pump 1 includes a compressor 2 that compresses the refrigerant, a radiator 3 that cools the refrigerant, a decompression unit 4 that decompresses the refrigerant, and an air heat exchanger 5 that evaporates and evaporates the refrigerant, and radiates heat from the discharge side of the compressor 2. The pressure reducing means 4 is connected via the compressor 3 and further connected to the suction side of the compressor 2.

  Further, in the heat pump 1, carbon dioxide is used as the refrigerant, and the refrigerant compressed by the compressor 2 enters the radiator 3 as a high-temperature and high-pressure supercritical refrigerant, where it radiates and cools. . Thereafter, the pressure is reduced in the pressure reducing means 4 to form low-temperature and low-pressure wet steam, and the air heat exchanger 5 exchanges heat with air to evaporate and return to the compressor 2. At this time, the blower 6 forcibly circulates the air to the air heat exchanger 5 in order to increase the heat exchange efficiency of the air heat exchanger 5.

  Discharge temperature detection means 36 for detecting the temperature of the refrigerant flowing between the compressor 2 and the radiator 3 and current value detection means 34 for detecting the current flowing through the compressor 2 are provided. The current detected by the current value detection means 34 may be a current flowing through the heat pump 1 or a current flowing through the entire heat pump water heater.

  The upper part of the hot water storage tank to which the boiling pipe 9 is connected is sufficient if the hot water is on the high temperature layer side of the hot water storage tank 8, and the lower part of the hot water storage tank 8 is if the hot water is on the low temperature layer side of the hot water storage tank. Good. In order to send hot water from the hot water storage tank 8 to the radiator 3 and return it to the hot water storage tank 8, a boiling pump 7 capable of arbitrarily changing the output is provided on the way.

Further, an incoming water temperature detecting means 15 for detecting the temperature of the low hot water before being heated in the heat pump 1 is provided near the radiator 3 inlet side of the incoming water pipe 18 and a hot water temperature detecting means 16 for detecting the temperature of the heated hot hot water. The heating tube 9 is provided near the outlet of the radiator 3. And in order to grasp | ascertain the temperature distribution and heat storage amount of the hot water storage tank 8, the hot water storage temperature sensor 17 is provided in the orthogonal | vertical direction on the outer wall surface.

  As a configuration related to hot water supply, a water supply pipe 19 for supplying water from a water supply source is connected, and the water supply source 19 supplies the water supply pipe 19 with a pressure reduced to an appropriate pressure by a pressure reducing valve 20. In addition, a hot water supply pipe 21 is connected to the upper part of the hot water storage tank 8 for discharging the hot water stored in the hot water and using it for hot water supply, and a water supply bypass pipe 22 from the water supply pipe 19 is connected in the middle thereof.

  Moreover, the mixing valve 23 which can mix the high temperature water from the hot water supply pipe 21 and the low temperature water from the water supply bypass pipe 22 in arbitrary ratios is provided. On the downstream side of the mixing valve 23, a hot water supply temperature sensor 25 is provided to detect the mixed hot water supply temperature, and a hot water supply terminal 24 is connected to the end thereof.

  As a configuration related to pouring water into the bath, a hot water pipe 28 branched from the middle of the hot water pipe 21 and poured into the bathtub 13 is provided. Like the hot water pipe 21, high hot water from the hot water pipe 21 is provided. A bath mixing valve 26 is provided so that the hot water from the water supply bypass pipe 22 can be mixed and poured, and a pouring temperature sensor 35 is provided downstream thereof. Moreover, the pouring pipe 28 is provided with a pouring electromagnetic valve 27, which is arbitrarily opened and closed to pour water into the bathtub 13 automatically.

  Regarding the circuit configuration of the bath heating operation for heating and keeping hot water in the bathtub 13, in the use side circuit 31, the hot water in the bathtub 13 is circulated to the bath heat exchanger 14 by the use side pump 12. In addition, a bath water temperature sensor 32 is provided to detect the temperature in the bathtub 13. Then, hot water in the hot water storage tank 8 is circulated to the bath heat exchanger 14 by the heat source side pump 11 and circulated to the hot water storage tank 8.

  In addition, a circulating temperature sensor 33 for detecting the temperature of hot water circulated and circulated by the use-side pump 11 from the bath heat exchanger 14 is attached.

  The compressor first stop means 37 includes a current value detection means 34 for detecting the value of the operating current of the compressor 2 and until the temperature and pressure states of the refrigeration cycle of the heat pump 1 become substantially constant after the compressor 2 is started. If the current value detected by the current value detection means 34 is equal to or greater than the predetermined value within the predetermined time, the operation of the compressor 2 is stopped.

  The compressor stop second means 38 includes an incoming water temperature detecting means 15 for detecting the incoming water temperature flowing into the radiator 3, a hot water temperature detecting means 16 for detecting the hot water temperature flowing out from the radiator 3, and the incoming water temperature detecting means 15. And a hot water temperature detection means 16, and a hot water temperature difference calculation means 41 for calculating a temperature difference between the detected incoming water temperature and the hot water temperature, respectively, and the calculation result of the hot water temperature difference calculation means 41 is less than a predetermined value. The operation of the compressor 2 is stopped.

  The compressor third stop means 39 includes a discharge temperature detection means 42 that detects the discharge temperature of the refrigerant from the compressor 2 until it flows into the radiator 3, the discharge temperature detection means 42, and the tapping temperature detection means 16. It comprises discharge hot water temperature difference calculating means 42 for calculating a temperature difference with the detected hot water temperature, and the operation of the compressor 2 is stopped when the calculation result of the discharged hot water temperature difference calculating means 42 is a predetermined value or more. .

  The compressor first stop means 37, the compressor stop second means 38, and the compressor third stop means 39 constitute a controller 43.

In the water heater configured as described above, the operation and action will be described below with reference to FIG.

  In the hot water storage operation in which hot water is stored in the hot water storage tank 8, the refrigerant compressed by the compressor 2 enters the radiator 3 as a high-temperature, high-pressure supercritical refrigerant, and heats water from the inlet pipe 18 here. Dissipate heat to cool. Thereafter, the pressure is reduced in the pressure reducing means 4 to become low-temperature and low-pressure wet steam, and the air heat exchanger 5 exchanges heat with air to evaporate and return to the compressor 2. At this time, the blower 6 forcibly circulates the air to the air heat exchanger 5 in order to increase the heat exchange efficiency of the air heat exchanger 5.

  Then, the temperature of the water heated by the heat pump 6 is detected by the tapping temperature sensor 16 and the output of the boiling pump 7 is changed to control the tapping temperature from the heat pump 6 so that the heating becomes the target temperature. Do.

  In this way, hot water is stored in the hot water storage tank 8, and the amount of heat stored in the hot water storage tank 8 is detected based on the temperature detected by the hot water storage temperature detection means 17 a, 17 b, 17 c, 17 d and the incoming water temperature sensor 15. When the predetermined heat storage amount is reached, the heat pump 1 is stopped.

  Further, when the compressor 2 starts operation, if the decompression means 4 is abnormal and is in a closed state, the current value continues to rise as the high pressure increases immediately after the compressor 2 is started, and the decompression valve 4 is in a normal state. A value exceeding the current value of. At this time, the current value detected by the current value detection means 34 is transmitted to the compressor stop first means, and if the current value is equal to or less than the predetermined current value within a predetermined time after the compressor 2 is started, the operation is performed. The operation of the compressor 2 is stopped when the current value is equal to or greater than the predetermined value.

  Further, when the compressor 2 starts operation, when the abnormality is generated in the boiling pump 7 and water is not circulated, the heat generated in the heat pump 1 cannot be transferred to the water, so that the high pressure increases. . Further, since heat cannot be transferred, there is no temperature difference between the incoming water temperature and the outgoing hot water temperature of the boiling pump 7.

  At this time, the incoming water temperature detected by the incoming water temperature detecting means 15 and the outgoing hot water temperature detected by the outgoing hot water temperature detecting means 16 are transmitted to the compressor stop second means, and after a predetermined time from the start of the compressor 2, the incoming water temperature and When the temperature difference of the tapping temperature is not more than a predetermined value, the operation of the compressor 2 is stopped. If the temperature difference between the incoming water temperature and the outgoing hot water temperature is greater than a predetermined value, the operation is continued.

  Furthermore, when the compressor 2 starts operation, when the abnormality occurs in the boiling pump 7 and the water is not circulated, the heat generated in the heat pump 1 cannot be transferred to the water, so that the high pressure increases. Thus, the hot water temperature does not rise despite the high discharge temperature. At this time, the discharge temperature detected by the discharge temperature detection means 36 and the hot water temperature detected by the hot water temperature detection means 16 are transmitted to the compressor stop third means, and after a predetermined time from the start of the compressor 2, the discharge temperature and If the temperature difference of the tapping temperature is larger than a predetermined value, the compressor 2 is stopped. The operation is continued if the temperature difference between the discharge temperature and the tapping temperature is not more than a predetermined value.

  In the hot water supply operation to the hot water supply terminal 24, when the hot water supply terminal 24 is opened for hot water supply, hot water in the hot water storage tank 8 is discharged from the hot water supply pipe 21 and supplied from the water supply pipe 19 to the hot water storage tank 8.

Further, the hot water supply temperature is changed by mixing the low temperature water from the water supply bypass pipe 22 branched from the water supply pipe 19, the hot water from the hot water storage tank 8 and the hot water mixing valve 23 at a mixing ratio. Hot water is supplied to the terminal 24. The mixing ratio at this time is controlled according to the hot water temperature detected by the hot water temperature sensor 25 and is kept at the hot water temperature selected by the user by a remote controller (not shown).

  In the pouring operation to the bath, when the pouring operation is started, the pouring solenoid valve 27 is opened, the water supply is branched by the water supply bypass pipe 22, and hot water from the hot water storage tank 8 and low hot water from the water supply are used for the bath. The mixing valve 26 changes the mixing ratio and mixes, so that the pouring temperature is changed and the bath 13 is poured. The mixing ratio at this time is controlled according to the pouring temperature detected by the pouring temperature sensor 35, and is kept at the pouring temperature selected by the user by a remote controller (not shown). That is, hot water is poured into the bathtub 13 by mixing the hot water and water in the hot water storage tank 8 and lowering the temperature.

  In the bath heating operation for heating the hot water in the bathtub 13, the heat of the hot water in the hot water storage tank 8 is radiated to the hot water in the bathtub 13. In the use side circuit 31, the flow path switching means 36 circulates hot water in the bathtub 13 to the bath heat exchanger 14 by the use side pump 12. On the other hand, in the heat source side circuit 30, the hot water in the hot water storage tank 8 is circulated to the bath heat exchanger 14 by the heat source side pump 11 and circulated to the hot water storage tank 8. In the bath heat exchanger 14, the hot water in the high temperature heat source side circuit 30 and the hot water in the usage side circuit 31 having a low temperature exchange heat to heat the hot water in the usage side circuit 31. This series of operations is continued until the bath temperature sensor 32 determines that the predetermined bath temperature has been reached.

  Thus, based on the current value detected by the current value detection means 34, the compressor stop first means for stopping the operation of the compressor, and the incoming water temperature and hot water temperature detection means 16 detected by the incoming water temperature detection means 15 are detected. The difference between the discharge temperature detected by the discharge temperature detection means 16 and the discharge temperature detected by the discharge temperature detection means 16 and the compressor stop second means for stopping the operation of the compressor 2 based on the difference temperature with the discharged hot water temperature A compressor stop third means for stopping the operation of the compressor 2 based on the temperature is provided.

  That is, by detecting an abnormality without using a pressure switch or a discharge pressure detecting means and stopping the compressor, it is possible to provide a long-term reliability improvement and a low-cost heat pump water heater.

  As described above, the heat pump water heater according to the present invention has high reliability over a long period of time by detecting an abnormality without using a pressure switch or a discharge pressure detecting means and stopping the compressor. Useful for low-cost heat pump water heaters.

Circuit diagram of heat pump water heater in Embodiment 1 of the present invention Circuit diagram of conventional heat pump water heater

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat pump 2 Compressor 3 Radiator 4 Pressure reduction means 5 Air heat exchanger 8 Hot water storage tank 15 Incoming water temperature detection means 16 Hot water temperature detection means 34 Current value detection means 36 Discharge temperature detection means 37 Compressor stop first means 38 Compressor stop Second means 39 Compressor stop third means 41 Hot water incoming water temperature difference calculating means 42 Discharged hot water temperature difference calculating means

Claims (4)

A heat pump formed by connecting a compressor, a radiator, a decompression unit, and an air heat exchanger, a hot water storage tank for storing hot water heated by the radiator, and a current value for detecting a current value flowing through the compressor A heat pump water heater comprising: a detecting unit configured to stop the operation of the compressor when the current value becomes a predetermined value or more within a predetermined time after the compressor is started. A heat pump formed by connecting a compressor, a radiator, a decompression means, and an air heat exchanger, a hot water storage tank for storing hot water heated by the radiator, and an incoming water for detecting an incoming water temperature flowing into the radiator A temperature detection means and a hot water temperature detection means for detecting the temperature of the hot water flowing out of the radiator, and after a predetermined time after the start of the compressor, a temperature difference between the incoming water temperature and the outgoing hot water temperature is a predetermined value. The heat pump water heater is configured to stop the operation of the compressor at the following times. A heat pump formed by connecting a compressor, a radiator, a decompression means, and an air heat exchanger, a hot water storage tank for storing hot water heated by the radiator, and a discharge temperature for detecting a compressor discharge temperature of the heat pump And a hot water temperature detecting means for detecting a hot water temperature flowing out from the radiator, and after a predetermined time after the compressor is started, a temperature difference between the discharge temperature and the hot water temperature is a predetermined value or more. When the heat pump water heater is configured to stop the operation of the compressor. The heat pump water heater according to any one of claims 1 to 3, wherein the refrigerant flowing through the radiator is pressurized to a supercritical pressure during compressor operation.

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