JP2005164209A - Heat-pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-pump water heater that can improve defrosting performance by conducting a refrigerant in a defrosting operation so as to cause a condensing action in an evaporative heat exchanger. <P>SOLUTION: The heat-pump water heater comprises: a hot water storage tank 10 for storing a supply of hot water; and a heat pump unit 20 connecting in a series circuit by refrigerant piping a compressor 21, a water heating heat exchanger 22 for providing heat exchange between a high pressure refrigerant and water taken in from a feedwater side of the hot water storage tank 10, an expansion valve 23 with electrically controllable valve opening the evaporative heat exchanger 24, and an accumulator 25 for accumulating the refrigerant as separating it into a vapor refrigerant and a liquid refrigerant. The accumulator 25 is designed to discharge a part of the liquid refrigerant into a suction refrigerant discharged to the compressor 21, in a defrosting operation of stopping the heat exchange in the water heating heat exchanger 22 and controlling the expansion valve 23 to predetermined valve opening to defrost the evaporative heat exchanger 24. The defrosting performance can be thus improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat pump hot water supply apparatus including a hot water storage tank for storing hot water for hot water supply and a heat source means including a heat pump cycle, and more particularly to improvement of defrosting performance in the heat pump cycle.

  Conventionally, as a heat pump hot water supply apparatus of this type, for example, as shown in Patent Document 1, normal operation for heating hot water for hot water in a hot water storage tank, and defrosting for removing frost attached to an evaporation heat exchanger A heat pump water heater having an operation is known. In this apparatus, a hot water storage tank for storing hot water for hot water supply, a heat pump cycle comprising a compressor, a heat exchanger for hot water supply, a pressure reducing means for electrically adjusting the valve opening degree, and a heat exchanger for evaporation, and a hot water tank A circulation pump that circulates the fluid to the hot water supply heat exchanger and a defrost control means for performing defrosting of the evaporation heat exchanger.

  Then, when performing the defrosting operation, the defrosting control unit adjusts the valve opening degree of the decompression unit to be larger than that during the normal operation, and controls to stop the operation of the circulation pump. In both the defrosting operation and the defrosting operation, in the heat pump cycle, the refrigerant flows in the order of the compressor, the hot water heat exchanger, the pressure reducing device, and the heat source heat exchanger.

According to this, the amount of thermal energy released from the high-temperature refrigerant (hot gas) discharged from the compressor by the hot water heat exchanger can be reduced, and the temperature drop due to the reduced pressure can be reduced even by the decompression means. As a result, the hot gas discharged from the compressor can reach the evaporating heat exchanger without greatly lowering the temperature, and the evaporating heat exchanger can be defrosted. That is, an increase in system cost can be prevented without newly adding functional parts (for example, a four-way valve, an on-off valve, etc.) for performing the defrosting operation (see, for example, Patent Document 1).
Japanese Patent No. 3297657

  However, according to the above-mentioned Patent Document 1, defrosting is performed using the sensible heat of hot gas flowing into the evaporation heat exchanger from the decompression means. In particular, in this type of heat pump water heater, the outside air temperature When the value becomes low, there is a problem that the defrosting operation time in the defrosting operation becomes longer due to an increase in frost adhesion in the normal operation.

  In view of the above, the object of the present invention is to improve the defrosting performance by allowing the refrigerant to flow through the evaporating heat exchanger so that a condensing action is generated during the defrosting operation. It is to provide a heat pump water heater.

In order to achieve the above object, the technical means described in claims 1 to 5 are employed. That is, according to the first aspect of the present invention, a hot water storage tank (10) in which water is supplied from a water supply source to the water supply side and hot water for hot water supply is stored on the hot water storage side, a compressor (21) for compressing refrigerant, and the compression A hot water supply heat exchanger (22) for exchanging heat between the high-pressure refrigerant discharged from the machine (21) and the water taken from the water supply side of the hot water storage tank (10), and a decompression means (23 for electrically adjusting the valve opening degree) ), An evaporating heat exchanger (24) that absorbs atmospheric heat, and an accumulator (25) that separates the refrigerant into a gas-phase refrigerant and a liquid-phase refrigerant and stores the refrigerant in order and connected in an annular manner with a refrigerant pipe (20) In a heat pump hot water supply apparatus comprising:
The heat source means (20) stops heat exchange of the hot water supply heat exchanger (22), adjusts the pressure reducing means (23) to a predetermined valve opening degree, and frost attached to the evaporation heat exchanger (24). The refrigeration cycle is configured so that the refrigerant sucked into the compressor (21) has a wetness degree when performing the defrosting operation to remove the water.

  According to the first aspect of the present invention, the refrigeration cycle is configured so that the suction refrigerant sucked into the compressor (21) has a wetness, so that the heat is positively generated during the defrosting operation. In the accumulator (25) that has not been exchanged, the refrigeration cycle balances so that the suction refrigerant discharged to the compressor (21) and the outflow refrigerant flowing out of the evaporating heat exchanger (24) match. Since the wetness of the suction refrigerant is provided, the refrigerant flowing out from the evaporation heat exchanger (24) matches. This is because the condensation action is generated in the evaporating heat exchanger (24), so that the condensation heat is added and the defrosting is performed rather than the conventional defrosting only by the sensible heat by the hot gas. Thereby, the direction of this invention can aim at the improvement of a defrosting performance.

  In the invention according to claim 2, the accumulator (25) discharges a part of the liquid-phase refrigerant to the suction refrigerant discharged to the compressor (21) during the defrosting operation more than during the boiling operation. It is characterized by being configured as described above. According to the invention described in claim 2, specifically, the accumulator (25) is configured to discharge a part of the liquid-phase refrigerant to the suction refrigerant discharged to the compressor (21). In the part of the accumulator (25) that does not perform heat exchange, the refrigerant state at the outlet and the refrigerant state at the inlet are balanced on the refrigeration cycle. That is, the same amount of liquid-phase refrigerant that has flowed out of the accumulator (25) flows into the accumulator (25) from the evaporation heat exchanger (24). At this time, in the heat exchanger for evaporation (24), a refrigerant condensing action is generated, and defrosting is performed by the latent heat of condensation. Thereby, condensation latent heat is added rather than what was defrosted by the conventional sensible heat, and it defrosts. Thereby, the direction of this invention can aim at the improvement of a defrosting performance.

  In the invention according to claim 3, the accumulator (25) has an outlet pipe (254) that is open to the gas-phase refrigerant in which the upstream end is stored and whose downstream end is connected to the suction side of the compressor (21). The outlet pipe (254) provided is characterized in that it is configured to open to some liquid-phase refrigerant stored near the upstream end only during the defrosting operation.

  According to the third aspect of the present invention, in the accumulator (25), during the defrosting operation, the liquid-phase refrigerant distributed in various places in the refrigeration cycle flows into the accumulator (25) and the liquid level of the liquid-phase refrigerant Is higher than in normal operation. Therefore, only when the defrosting operation is performed, it is configured to open to a part of the liquid-phase refrigerant stored in the vicinity of the upstream end, so that the suction refrigerant discharged from the outlet pipe (254) to the compressor (21) can be reduced. A part of the liquid phase refrigerant can be discharged.

  In the invention according to claim 4, between the evaporating heat exchanger (24) and the accumulator (25), the refrigerant that flows into the accumulator (25) is activated during the defrosting operation and heated. The heating means (27) is provided.

  According to the invention described in claim 4, the refrigerant state at the outlet of the accumulator (25) is generally a saturated gas state. Therefore, the refrigerant flowing out of the evaporating heat exchanger (24) is heated by the heating means (27), so that the refrigerant state at the inlet flowing into the accumulator (25) can be matched with the refrigerant state at the outlet. As a result, an amount of liquid-phase refrigerant corresponding to the heating amount of the heating means (27) can be caused to flow out of the evaporation heat exchanger (24). Therefore, in the heat exchanger for evaporation (24), a refrigerant condensing action is generated, and defrosting can be performed by the latent heat of condensation.

  In the invention according to claim 5, the accumulator (25) is provided with heating means (27) for operating and heating the refrigerant stored in the accumulator (25) during the defrosting operation. It is said. According to the fifth aspect of the present invention, the accumulator (25) except for the outlet pipe (254) of the accumulator (25), in addition to the above-described evaporation heat exchanger (24) and the accumulator (25). The main body also flows into the accumulator (25) by heating the refrigerant flowing out of the evaporating heat exchanger (24), that is, the stored refrigerant by the heating means (27), as in the fourth aspect. The refrigerant state at the inlet can be matched with the refrigerant state at the outlet. As a result, an amount of liquid-phase refrigerant corresponding to the heating amount of the heating means (27) can be caused to flow out of the evaporation heat exchanger (24). Therefore, in the heat exchanger for evaporation (24), a refrigerant condensing action is generated, and defrosting can be performed by the latent heat of condensation.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment mentioned later.

(First embodiment)
Hereinafter, a heat pump hot water supply apparatus according to a first embodiment to which the present invention is applied will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic diagram showing the overall configuration of a heat pump hot water supply apparatus, and FIG. 2 is a longitudinal sectional view showing the overall configuration of an accumulator 25 in the present embodiment. As shown in FIG. 1, the heat pump hot water supply apparatus of the present embodiment includes a heat pump unit 10 that is a heat source means, a hot water storage tank 20 that stores hot water for hot water supply, a circulating water circuit 30 that connects the heat pump unit 10 and the hot water storage tank 20, and It is comprised from the control apparatus 40 etc. which are control means.

First, the heat pump unit 20 is configured by connecting a compressor 21, a hot water supply heat exchanger 22, an expansion valve 23 that is a decompression means, an evaporating heat exchanger 24, and an accumulator 25 in order through a refrigerant pipe 26. Carbon dioxide CO ₂ having a low critical temperature is used. The compressor 21 is driven by a built-in electric motor (not shown), and compresses and discharges the suction refrigerant sucked from the accumulator 25 to a critical pressure or higher under general use conditions.

The hot water supply heat exchanger 22 exchanges heat between the high temperature refrigerant (hot gas) discharged from the compressor 21 and the hot water supply water supplied from the hot water storage tank 20, and a refrigerant passage (through which the refrigerant flows) ( (Not shown) and a fluid passage (not shown) through which hot water flows. The flow direction of the refrigerant flowing through the refrigerant passage and the flow direction of the hot water flowing through the fluid passage are opposed to each other. It is configured. Since the refrigerant (CO ₂ ) flowing through the hot water supply heat exchanger 22 is pressurized to a critical pressure or higher by the compressor 21, the temperature is lowered by dissipating heat to the hot water supply water flowing through the hot water supply heat exchanger 22. However, it does not condense.

  The expansion valve 23, which is a decompression means, is a decompression device that decompresses the refrigerant flowing out of the hot water supply heat exchanger 22 in accordance with the valve opening, and the valve opening is electrically controlled by the control device 40. Yes. The evaporating heat exchanger 24 absorbs the refrigerant decompressed by the expansion valve 23 by heat exchange with the outside air blown by the blower 24a. Next, the accumulator 25 gas-liquid separates the refrigerant evaporated by the evaporating heat exchanger 24, stores the liquid phase refrigerant, causes only the gas phase refrigerant to be sucked into the compressor 21, and stores excess refrigerant in the cycle. It is something to keep.

  By the way, the accumulator 25 of this embodiment of this invention is comprised so that a part liquid phase refrigerant | coolant may be discharged to the suction | inhalation refrigerant | coolant discharged to the compressor 21 from the exit piping 254, when performing the defrost operation mentioned later. Yes. Specifically, as shown in FIG. 2, a cylinder 251 having a substantially cylindrical shape and a pressure vessel for storing a liquid-phase refrigerant in which end plates 252 are joined to both ends thereof, an inlet pipe 253 on an upper end plate 252, The lower end plate 252 includes an exit pipe 254 and a collision member 255 below the downstream end of the inlet pipe 253.

  The inlet pipe 253 is formed so that the gas-liquid mixed refrigerant that has flowed into the opening at the lower end collides with the collision member 255, and the collision member 255 receives the gas-liquid mixed refrigerant that flows from the inlet pipe 253. It is a member that promotes gas-liquid separation by collision. Therefore, the liquid-phase refrigerant that has been subjected to gas-liquid separation is stored below the collision member 255.

  The outlet pipe 254 has an opening 254a at the upper end, an opening 254b near the lower part of the opening 254a, and an oil return hole 254c below the opening 254a. During normal operation, the opening 254a is open. The gas phase refrigerant is configured to flow out from the outlet pipe 254 by communicating with the phase refrigerant, and during the defrosting operation, the opening hole 254b communicates with the liquid phase refrigerant so that a part of the liquid refrigerant is included in the gas phase refrigerant. The refrigerant is mixed and flows out from the outlet pipe 254 to the compressor 21.

  In the defrosting operation, the hot water supply water flowing through the fluid passage side of the hot water supply heat exchanger 22 is stopped and the refrigeration cycle is operated in the accumulator 25 as compared with the normal operation. The upper end of the liquid-phase refrigerant is accumulated up to the vicinity of the opening hole 254b.

By the way, the heat pump unit 20 configured as described above is a supercritical heat pump, and this supercritical heat pump refers to a heat pump cycle in which the refrigerant pressure on the high-pressure side is equal to or higher than the critical pressure of the refrigerant. In addition to CO ₂ , ethylene, ethane, nitric oxide or the like may be used. Incidentally, according to this supercritical heat pump, hot water for hot water supply having a temperature higher than that of a general heat pump cycle (for example, about 85 ° C. to 90 ° C.) can be boiled.

  Next, the hot water storage tank 10 is made of metal (for example, made of stainless steel) excellent in corrosion resistance, is formed in a vertically long shape, and a heat insulating material (not shown) is disposed on the outer peripheral portion, so that hot water for hot water supply can be used for a long time. Can be kept warm. In addition, an inlet 10a is provided on the bottom surface, and a water supply pipe 11 for introducing tap water into the hot water storage tank 10 is connected to the inlet 10a. In addition, upstream of the water supply pipe 11 is connected to tap water through a pressure reducing check valve and an on-off valve (not shown) to introduce tap water having a predetermined pressure.

  On the other hand, an outlet 10b is provided at the top of the hot water storage tank 10, and a hot water supply pipe 12 for connecting hot water for hot water supply in the hot water storage tank 10 is connected to the outlet 10b. A discharge pipe provided with a relief valve (not shown) is connected in the middle of the route of the hot water supply pipe 12. When the pressure in the hot water storage tank 10 rises to a predetermined pressure or higher, the hot water in the hot water storage tank 10 is supplied. Is discharged to the outside so as not to damage the hot water storage tank 10 or the like.

  Furthermore, hot water mixing means (not shown) is connected in the course of the hot water supply pipe 12 so that hot water in the hot water storage tank 10 and tap water are mixed to obtain hot water at a predetermined temperature. . In addition, a suction port 10 c for sucking water in the hot water storage tank 10 is provided in the lower part of the hot water storage tank 10, while hot water boiled in the hot water storage tank 10 is discharged in the upper part of the hot water storage tank 10. A discharge port 10d is provided.

  Next, the circulating water circuit 30 includes a cold water pipe 31a, a hot water pipe 31b, a circulation pump 32, and the like connected to a fluid passage (not shown) of the hot water supply heat exchanger 22. The cold water pipe 31a has an upstream end connected to a lower part (suction port 10c) of the hot water storage tank 10, and a hot water pipe 31b has a downstream end connected to an upper part (discharge port 10d) of the hot water storage tank 10.

  The circulation pump 32 is provided in the cold water pipe 31 a (or may be the hot water pipe 31 b), and is energized and rotated to circulate hot water supply water in the hot water storage tank 10 to the circulation water circuit 30. As shown by the arrows in FIG. 1, the flow direction of the hot water supply water is a lower portion 10 c in the hot water storage tank 10 → the cold water pipe 31 a → the fluid passage of the hot water supply heat exchange 22 → the hot water pipe 31 b → the hot water storage tank 10. It flows to the upper part 10d.

  Next, the control device 40 controls the energization of the compressor 21 (electric motor), the blower 24a, the expansion valve 23, and the circulation pump 32, and supplies hot water stored in the hot water storage tank 10 to a predetermined temperature range ( For example, boiling operation (hereinafter referred to as normal operation) is performed so that the temperature is 60 to 90 ° C. When the outside air temperature becomes low, frost adheres to the evaporating heat exchanger 24 by this normal operation, so that in addition to the normal operation, the compressor 21 (electric motor), the expansion valve 23, and the circulation pump 32 is energized to perform a defrosting operation for removing frost adhering to the evaporation heat exchanger 24.

  The defrosting operation is controlled by a defrosting control means provided in the control device 40, and is performed based on the flowchart shown in FIG. In the present embodiment, a temperature sensor 41 that detects the outlet refrigerant temperature of the evaporating heat exchanger 24 and an outside air temperature sensor 42 that detects the outside air temperature are provided. Based on the detection values of these temperature sensors 41 and 42. Defrosting operation. As an example, the defrosting operation is started when the detected value of the outside air temperature sensor 42 is 10 ° C. or less and the temperature difference between the detected value of the temperature sensor 41 and the detected value of the outside air temperature sensor 42 is 10 ° C. or more. The defrosting operation is terminated when the detection value of the sensor 41 rises to 10 ° C. or higher.

  Next, the operation of the heat pump water heater having the above configuration will be described. During normal operation in which hot water in the hot water storage tank 102 is supplied to the hot water heat exchanger 22 and heated, the temperature of the hot water heated by the hot water heat exchanger 22 is a predetermined temperature (for example, 85 ° C.). ), The flow rate of the fluid flowing through the fluid passage of the hot water supply heat exchanger 22 is controlled by the circulation pump 32. The hot water supply heat exchanger 22 is configured such that the flow direction of the refrigerant and the flow direction of the fluid face each other, so that the hot water supply water flowing in the hot water supply heat exchanger 22 flows from the inlet to the outlet. The temperature rises as you go. In the expansion valve 23 on the heat pump cycle side, the refrigerant pressure at the refrigerant inlet of the hot water supply heat exchanger 22 (the discharge pressure of the compressor 21) corresponds to the refrigerant temperature necessary for obtaining the above-described hot water temperature. The valve opening degree of the expansion valve 23 is controlled through the control device 40 so as to be the pressure.

  And when performing said normal operation, a defrost operation is performed by a defrost control means. Hereinafter, the defrosting operation based on the flowchart of the defrosting control means shown in FIG. 3 will be described. First, as shown in FIG. 3, it is determined in step 410 whether or not normal operation is being performed. If normal operation is being performed, it is determined in step 420 whether or not the detected value of the outside air temperature sensor 42, that is, the outside air temperature is 10 ° C. or less. Here, if the outside air temperature is 10 ° C. or higher, the normal operation is continued.

  If the outside air temperature is 10 ° C. or less, in step 430, the temperature difference between the detected value of the temperature sensor 41 and the detected value of the outside air temperature sensor 42, that is, the outside air temperature and the refrigerant outlet temperature of the evaporating heat exchanger 24. It is determined whether or not the temperature difference is 10 ° C. or more. If the temperature difference is 10 ° C. or less, normal operation is continued. If the temperature difference is 10 ° C. or more, in step 440, the normal operation is switched to the defrosting operation, and the valve opening of the expansion valve 23 is first opened to a specified value. Note that the valve opening at this time is larger (for example, fully open) than during normal operation.

  In step 450, the circulation pump 32 is stopped, and in step 460, the rotational speed of the compressor 21 is changed to the defrosting rotational speed. In step 470, it is determined whether or not the refrigerant outlet temperature of the evaporating heat exchanger 24 has exceeded 10 ° C, and the defrosting operation is continued until the refrigerant outlet temperature exceeds 10 ° C. Here, if the refrigerant outlet temperature exceeds 10 ° C., it is determined that the defrosting is finished, and in step 480, the valve opening degree of the expansion valve 23, the circulation pump 32, and the compressor 21 are controlled and removed. Switch from frost operation to normal operation. Thereby, the amount of heat energy released by the high-temperature refrigerant discharged from the compressor 21 at the hot water supply heat exchanger 22 can be reduced, and the temperature drop due to the decompression at the expansion valve 23 can be reduced. As a result, the high-temperature refrigerant discharged from the compressor 22 reaches the evaporating heat exchanger 24 without greatly reducing the temperature, and defrosting of frost adhering to the evaporating heat exchanger 24 is performed.

  By the way, in the high-temperature refrigerant discharged from the compressor 21 during the defrosting operation, a part of the liquid-phase refrigerant, that is, the wetness is mixed with the gas-phase refrigerant flowing into the compressor 21 from the accumulator 25. By configuring the 25 outlet pipes 254, a part of the liquid-phase refrigerant is mixed in the gas-phase refrigerant. That is, during the defrosting operation, the heat exchanger 22 for hot water supply is not dissipated so that the liquid refrigerant distributed in various places in the refrigeration cycle flows into the accumulator 25 and flows in the liquid phase refrigerant more than during normal operation. The liquid level rises.

  Therefore, the opening hole 254a communicates with the liquid phase refrigerant, and a part of the liquid phase refrigerant flows out of the opening hole 254a into the outlet pipe 254 and is mixed into the gas phase refrigerant. Accordingly, a part of the liquid phase refrigerant is mixed with the gas phase refrigerant and discharged to the compressor 21, and therefore, the accumulator 25 receives the same amount of the liquid phase refrigerant as the part of the liquid phase refrigerant discharged from the outlet pipe 254. It is balanced so as to flow in from the pipe 253.

  As a result, a condensing action is generated in the evaporating heat exchanger 24, and defrosting is performed by the latent heat of condensation at this time. As described above, the suction refrigerant flowing into the compressor 21 from the accumulator 25 is a refrigerant having a wetness by mixing a part of the liquid-phase refrigerant into the gas-phase refrigerant more than in normal operation. .

  According to the heat pump hot water supply apparatus of the first embodiment described above, the accumulator 25 is configured so that the refrigerant sucked into the compressor 21 has a wetness, so that the heat for hot water supply can be obtained during the defrosting operation. If heat exchange is not actively performed in the exchanger 22, the accumulator 25 refrigerates the refrigeration cycle so that the suction refrigerant discharged to the compressor 21 and the outflow refrigerant flowing out of the evaporation heat exchanger 24 coincide with each other. Therefore, when the suction refrigerant has a wetness, the refrigerant flowing out from the evaporating heat exchanger 24 matches the refrigerant. This is because the condensation effect is generated in the evaporating heat exchanger 24, so that the condensation heat is added and the defrosting is performed more than the conventional defrosting only by the sensible heat by the hot gas. Thereby, the direction of this invention can aim at the improvement of a defrosting performance.

  Specifically, the accumulator 25 is configured such that a part of the liquid-phase refrigerant is discharged to the suction refrigerant discharged to the compressor 21 more than the normal operation, so that the accumulator 25 that is not actively exchanging heat is used. In the part, the refrigerant state is balanced on the refrigeration cycle so that the refrigerant state at the outlet and the refrigerant state at the inlet coincide. That is, the same amount of liquid-phase refrigerant that has flowed out of the accumulator 25 flows into the accumulator 25 from the evaporation heat exchanger 24. At this time, the evaporating heat exchanger 24 has a refrigerant condensing action, and defrosting is performed by the latent heat of condensation. Thereby, condensation latent heat is added rather than what was defrosted by the conventional sensible heat, and it defrosts. Thereby, the condensation defrost heat can improve the defrosting performance rather than the sensible heat.

  Further, the accumulator 25 is provided with an outlet pipe 254 that is opened to the gas-phase refrigerant in which the upstream end is stored and whose downstream end is connected to the suction side of the compressor 21, and this outlet pipe 254 is used for defrosting operation. Since only a part of the liquid-phase refrigerant stored near the upstream end is opened, the liquid-phase refrigerant distributed in various parts of the refrigeration cycle flows into the accumulator 25 during the defrosting operation. As a result, the liquid level of the liquid phase refrigerant rises higher than that during normal operation, so that part of the liquid phase refrigerant can be discharged to the suction refrigerant discharged from the outlet pipe 254 to the compressor 21.

(Second Embodiment)
In the first embodiment described above, when performing the defrosting operation, the heat exchange of the hot water supply heat exchanger 22 is stopped, and a part of the liquid refrigerant is mixed into the suction refrigerant discharged from the accumulator 25 to the compressor 21. Although the accumulator 25 is configured as described above, the present invention is not limited to this, and the accumulator 25 is configured so that only the gas-phase refrigerant is discharged to the compressor 21, and the downstream side of the evaporation heat exchanger 24 and the accumulator 25. In the meantime, the heating means 27 for heating the refrigerant flowing into the accumulator 25 only during the defrosting operation may be configured.

  Specifically, as shown in FIG. 4, heating means 27 is provided between the downstream side of the evaporation heat exchanger 24 and the accumulator 25 to heat the refrigerant flowing into the accumulator 25 only during the defrosting operation. Is. This is because a part of the liquid-phase refrigerant condensed in the evaporating heat exchanger 24 is heated by the heating means 27 so that the gas-phase refrigerant flows into the accumulator 25, thereby evaporating heat exchange. The container 24 can generate a condensing action as in the first embodiment. In addition, the code | symbol shown in the figure attaches | subjects the same code | symbol as the structure similar to 1st Embodiment, and abbreviate | omits description.

  According to the heat pump hot water supply apparatus of the second embodiment described above, heating is performed between the evaporation heat exchanger 24 and the accumulator 25 by operating the refrigerant flowing into the accumulator 25 during heating in the defrosting operation. By providing the means 27, the refrigerant state at the outlet of the accumulator 25 is generally a saturated gas state.

  Accordingly, the refrigerant flowing out of the evaporating heat exchanger 24 is heated by the heating means 27 so that the refrigerant state at the inlet flowing into the accumulator 25 can be matched with the refrigerant state at the outlet. As a result, an amount of liquid refrigerant corresponding to the heating amount of the heating means 27 can be caused to flow out of the evaporating heat exchanger 24. Therefore, in the heat exchanger 24 for evaporation, a refrigerant condensing action is generated, and defrosting can be performed by the condensation latent heat.

  In the above configuration, the heating means 27 is disposed between the evaporation heat exchanger 24 and the accumulator 25. However, the present invention is not limited to this, and the accumulator 25 body excluding the outlet pipe 254 of the accumulator 25 is also excluded. A heating means 27 that operates during the frost operation may be provided. According to this, in the same way as described above, the accumulated refrigerant is heated by the heating means 27 in the accumulator 25, whereby the refrigerant state at the inlet flowing into the accumulator 25 can be matched with the refrigerant state at the outlet. As a result, an amount of liquid refrigerant corresponding to the heating amount of the heating means 27 can be caused to flow out of the evaporating heat exchanger 24. Therefore, in the heat exchanger 24 for evaporation, a refrigerant condensing action is generated, and defrosting can be performed by the condensation latent heat.

(Other embodiments)
In the first embodiment described above, one opening hole 254b formed in the outlet pipe 254 of the accumulator 25 is formed near the lower portion of the opening 254a. However, the present invention is not limited to this, and a plurality of opening holes 254b may be formed. Further, as shown in FIG. 5, an opening hole 254b may be formed so as to extend from the opening 254a. Further, the upstream end of the outlet pipe 254 may be disposed near the liquid surface during the defrosting operation, and the height of the opening 254a and the amount of the liquid phase refrigerant may be adjusted so that a part of the liquid phase refrigerant is mixed.

  In the above embodiment, the present invention is applied to the heat pump unit 20 including a supercritical heat pump including refrigerant functional parts such as the compressor 21, the hot water supply heat exchanger 22, the expansion valve 23, the evaporation heat exchanger 24, and the accumulator 25. However, the present invention is not limited to this, and may be applied to heat source means constituting a general heat pump cycle.

  Moreover, in the above embodiment, hot water for hot water stored in the hot water storage tank 10 may be used as it is for drinking water, bath water, etc., but the hot water in the hot water storage tank 10 is heated for drinking water and bath water. You may use as a heat carrier for doing. The hot water in the hot water storage tank 10 may be used not only for hot water supply but also for floor heating and indoor air conditioning.

It is a schematic diagram which shows the whole structure of the heat pump hot-water supply apparatus in 1st Embodiment of this invention. It is a longitudinal cross-sectional view which shows the whole structure of the accumulator 25 in 1st Embodiment of this invention. It is a flowchart which shows the control processing of the defrost control means in 1st Embodiment of this invention. It is a schematic diagram which shows the whole structure of the heat pump hot-water supply apparatus in 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the whole structure of the accumulator 25 in other embodiment.

Explanation of symbols

10 ... Hot water storage tank 20 ... Heat pump unit (heat source means)
DESCRIPTION OF SYMBOLS 21 ... Compressor 22 ... Heat exchanger for hot water supply 23 ... Expansion valve (pressure reduction means)
24 ... Evaporation heat exchanger 25 ... Accumulator 27 ... Heating means 254 ... Outlet piping

Claims (5)

A hot water storage tank (10) in which water is supplied from the water supply source to the water supply side, and hot water for hot water supply is stored on the hot water storage side;
A compressor (21) for compressing the refrigerant, a hot water supply heat exchanger (22) for exchanging heat between the high-pressure refrigerant discharged from the compressor (21) and water taken from the water supply side of the hot water storage tank (10), Pressure reducing means (23) that electrically adjusts the valve opening, an evaporating heat exchanger (24) that absorbs atmospheric heat, and an accumulator (25) that separates the refrigerant into a gas-phase refrigerant and a liquid-phase refrigerant and stores the refrigerant In a heat pump hot water supply device comprising heat source means (20) connected in an annular manner with a refrigerant pipe in order,
The heat source means (20) stops heat exchange of the hot water supply heat exchanger (22), adjusts the pressure reducing means (23) to a predetermined valve opening degree, and supplies the evaporation heat exchanger (24). A heat pump hot water supply apparatus, wherein a refrigeration cycle is configured so that the refrigerant sucked into the compressor (21) has a wetness degree when performing a defrosting operation to remove adhering frost.   The accumulator (25) is configured to discharge a part of the liquid-phase refrigerant to the suction refrigerant discharged to the compressor (21) during the defrosting operation more than during the boiling operation. The heat pump hot-water supply apparatus according to claim 1, wherein   The accumulator (25) is provided with an outlet pipe (254) having an upstream end opened to a gas-phase refrigerant stored therein and a downstream end connected to the suction side of the compressor (21). The heat pump hot water supply apparatus according to claim 2, wherein 254) is configured to open to a part of the liquid-phase refrigerant stored near the upstream end only during the defrosting operation.   Between the evaporating heat exchanger (24) and the accumulator (25), heating means (27) for heating the refrigerant flowing into the accumulator (25) by operating it during the defrosting operation. The heat pump hot water supply apparatus according to claim 1, wherein:   The said accumulator (25) is provided with the heating means (27) which act | operates and heats the refrigerant | coolant stored in the said accumulator (25) at the time of the said defrost operation. Heat pump water heater.

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