JP2008196769A - Heat pump hot-water supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure durability of a compressor even when a temperature of the water flowing into a heat exchanger for hot water supply is high. <P>SOLUTION: This heat pump hot-water supply device is constituted by circularly connecting the compressor 21, the heat exchanger 22 for hot water supply, a first expansion valve 23, a heat accumulator 25, a first opening and closing valve 28, a second expansion valve 29 and an evaporator 30 by piping, and comprises a first bypass circuit 32 bypassing the first expansion valve 23, the heat accumulator 25 and the first opening and closing valve 28 and provided with a second opening and closing valve 33, a heat pump cycle 20 connecting the piping between the heat accumulator 25 and the first opening and closing valve 28 and the piping between the compressor 21 and the evaporator 30, and provided with a second bypass circuit 34 provided with a third opening and closing valve 35, and a hot water storage tank 41 for storing the hot water heated by using the heat pump cycle 20, and the heat of a refrigerant coming out from the heat exchanger 22 for hot water supply is accumulated by the heat accumulator 25, when a water supply temperature is high. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat pump water heater.

  Conventionally, hot water supply apparatuses using various heat pump cycles have been proposed, and an example thereof will be described with reference to FIG.

  FIG. 3 is a configuration diagram of a conventional heat pump water heater.

  As shown in FIG. 3, the conventional heat pump water heater is a refrigerant circulation circuit comprising a compressor 1, a hot water supply heat exchanger 2, a throttling device 3, and an evaporator 4, a hot water tank 5, a circulation pump 6, and a hot water supply heat exchange. It consists of a hot water supply circuit to which a heater 2 and an auxiliary heater 7 are connected.

  The high-temperature and high-pressure superheated gas discharged from the compressor 1 flows into the hot water supply heat exchanger 2, where the hot water supplied by the circulation pump 6 is heated. Then, the condensed and liquefied refrigerant is decompressed by the expansion device 3 and flows into the evaporator 4 where it absorbs atmospheric heat to evaporate and returns to the compressor 1 to become high-temperature and high-pressure superheated gas again.

On the other hand, hot water heated by the hot water supply heat exchanger 2 flows into the upper part of the hot water storage tank 5 and is gradually stored from above. Then, when the inlet water temperature of the hot water supply heat exchanger 2 reaches a set value, the water temperature detector 8 detects it, stops the heat pump operation by the compressor 1, and switches to the auxiliary operation of the auxiliary heater 7 (for example, Patent Documents). 1).
JP 60-164157 A

  However, in the conventional configuration, as the boiling operation time elapses, a hot water mixed layer is formed at a portion where the hot water in the hot water tank 5 is in contact with water, and the layer gradually expands. This occurs due to heat conduction and convection in high temperature hot water and low temperature water. Heat is transferred from the high temperature hot water to the low temperature water, and the temperature of the high temperature hot water decreases at the boundary portion, while the temperature of the low temperature water increases.

  Accordingly, when the boiling operation is nearly completed, the temperature of the water flowing into the hot water supply heat exchanger 2 becomes high, so that the discharge pressure of the compressor 1 increases and the durability of the compressor 1 deteriorates. It was.

  This invention solves the said conventional subject, and it aims at providing the heat pump hot-water supply apparatus which ensured the durability of the compressor, even when the water temperature which flows in into the heat exchanger for hot water supply is high.

  In order to solve the conventional problems, a heat pump hot water supply apparatus of the present invention includes a compressor, a heat exchanger for hot water supply, a first expansion valve, a heat accumulator, a first on-off valve, a second expansion valve, and evaporation. A first bypass circuit in which a vessel is annularly connected, bypassing the first expansion valve, the heat accumulator, and the first on-off valve and provided with a second on-off valve, and the heat accumulator A heat pump cycle in which a pipe between the first on-off valve and a pipe between the compressor and the evaporator are connected and a second bypass circuit provided with a third on-off valve is provided; and the heat pump cycle is It has a hot water storage tank for storing hot water that has been used and heated.

  With a heat storage unit, when the incoming water temperature is high, the outlet temperature of the hot water heat exchanger also rises in the normal heat pump cycle, and the refrigerant hold amount of the hot water heat exchanger and evaporator decreases, increasing the high pressure. However, by storing the heat of the refrigerant in the heat accumulator as in the present invention and cooling the refrigerant that has exited the hot water heat exchanger, the refrigerant enthalpy is reduced and its density is increased. Since the dryness of the evaporator inlet also decreases and the refrigerant hold amount of the evaporator increases, the heat pump cycle can be operated safely without increasing the high pressure even when the incoming water temperature is high.

  The heat pump water heater of the present invention can ensure the durability of the compressor even when the water temperature flowing into the hot water heat exchanger is high.

  According to a first aspect of the present invention, a compressor, a hot water supply heat exchanger, a first expansion valve, a heat accumulator, a first on-off valve, a second expansion valve, and an evaporator are connected in a ring shape with a pipe, and the first A first bypass circuit that bypasses the first on-off valve, the second on-off valve, and a pipe between the regenerator and the first on-off valve, A heat pump cycle that connects a pipe between the compressor and the evaporator and includes a second bypass circuit provided with a third on-off valve; and a hot water storage tank that stores hot water heated using the heat pump cycle ing.

  With this configuration, when the incoming water temperature is high, in the normal heat pump cycle, the outlet temperature of the hot water heat exchanger also rises, and the refrigerant hold amount of the hot water heat exchanger and the evaporator decreases, so the high pressure tends to rise. However, by storing the heat of the refrigerant in the regenerator as in the present invention and cooling the refrigerant that has exited the hot water heat exchanger, the refrigerant enthalpy is reduced and its density is increased. Since the dryness of the inlet also decreases and the refrigerant hold amount of the evaporator increases, the heat pump cycle can be operated safely without increasing the high pressure even when the incoming water temperature is high.

  In particular, in the heat pump water heater of the first invention, the second aspect of the invention is a water inlet temperature detection means for detecting the temperature of the water side inlet of the heat exchanger for hot water supply, and a regenerator temperature for detecting the temperature of the regenerator. Detecting means, and depending on the temperature of the water-side inlet of the hot water heat exchanger detected by the incoming water temperature detector and the temperature of the regenerator detected by the regenerator temperature detecting means, The on-off valve 1, the second on-off valve, and the third on-off valve are controlled.

  With this configuration, the heat accumulator can act as a heat absorber and a heat sink, and when the heat accumulator acts as a heat radiator, the heat absorbed can be recovered, so that a more efficient heat pump water heater can be realized.

  According to a third aspect of the invention, in particular, in the heat pump water heater of the second aspect of the invention, when the first on-off valve is closed, the second on-off valve is open, and the third on-off valve is open, Decreasing the capacity of the evaporator.

  With this configuration, the fan input, that is, the input to the heat pump cycle can be reduced, so that a more efficient heat pump water heater can be realized.

  In a fourth aspect of the invention, in particular, in the heat pump hot water supply apparatus of the second or third aspect of the invention, the heat accumulator is filled with a latent heat storage agent.

  With this configuration, heat is dissipated to the regenerator made of the latent heat storage agent at the end of boiling operation, so the rise in the outlet temperature of the regenerator can be moderated, and further the increase in high pressure can be moderated. An efficient heat pump water heater can be realized.

  Furthermore, since the heat stored in the regenerator can be recovered, a more efficient heat pump water heater can be realized.

  In a fifth aspect of the invention, in particular, in the heat pump hot water supply apparatus of the second or third aspect of the invention, the regenerator is filled with a plurality of latent heat storage agents having different melting points.

  With this configuration, since the amount of heat that can be recovered by filling the heat accumulator with a plurality of latent heat storage agents having different melting points is increased, a more efficient heat pump water heater can be realized.

  In a sixth aspect of the invention, in particular, in the heat pump hot water supply apparatus of the fifth aspect of the invention, in the heat accumulator, the refrigerant flows from a latent heat storage agent having a high melting point to a latent heat storage agent having a low melting point.

  This configuration dissipates heat to the regenerator where the refrigerant flows from the latent heat storage agent with a high melting point to the latent heat storage agent with a low melting point at the end of boiling operation. Since the rise can be further moderated, a more efficient heat pump water heater can be realized during heat pump cycle operation.

  Further, since the amount of heat that can be recovered by filling the heat accumulator with a plurality of latent heat storage agents having different melting points is increased, a more efficient heat pump water heater can be realized.

  In the seventh invention, in particular, in any one of the second to sixth inventions, the refrigerant used in the heat pump cycle is carbon dioxide, and the high pressure side is operated in a state exceeding the critical pressure.

  With this configuration, the hot water supply can be heated at high efficiency, and even when the refrigerant leaks to the outside, the influence on global warming is very small.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiment.
(Embodiment 1)
FIG. 1 is a configuration diagram of a refrigeration circuit of a heat pump hot water supply apparatus according to a first embodiment of the present invention.

  As shown in the figure, the heat pump cycle 20 includes a compressor 21, a hot water heat exchanger 22, a first expansion valve 23, a heat accumulator 25, a first on-off valve 28, a second expansion valve 29, and an evaporator. 30 is connected in an annular shape by piping. Note that a fan 31 for blowing air to the evaporator 30 is provided.

  In addition, a first bypass circuit 32 that bypasses the first expansion valve 23, the heat accumulator 25, and the first on-off valve 28 is provided, and the second on-off valve 33 is provided in the first bypass circuit 32. ing.

  In addition, a second bypass circuit 34 is provided in which a pipe between the heat accumulator 25 and the first on-off valve 28 and a pipe between the compressor 21 and the evaporator 30 are connected. Is provided with a third on-off valve 35.

  A fourth on-off valve 24 is provided in parallel with the first expansion valve 23.

  The regenerator 25 is composed of a high melting point latent heat storage agent 26 and a low melting point latent heat storage agent 27, and is provided with a regenerator temperature detection means 25A.

  The controller 36 receives the hot water temperature detected by the incoming water temperature detection means 22B, which will be described later, and the regenerator temperature detected by the regenerator temperature detection means 25A, and is output by the on-off valve setting means 37. The opening / closing of the second on-off valve 33, the third on-off valve 35, and the fourth on-off valve 24 is set.

  In addition, it is preferable that the heat pump hot-water supply apparatus by a present Example uses a carbon dioxide as a refrigerant | coolant, and it drive | operates in the state exceeding a critical pressure on the high pressure side.

  Next, a hot water supply circuit of the heat pump hot water supply apparatus in the first embodiment of the present invention will be described.

  The first bottom pipe 42 of the hot water storage tank 41 is connected to a water supply pipe 44 such as a water pipe via a pressure reducing valve 43, and water is supplied from the first bottom pipe 42 to the hot water storage tank 41 in a state where the pressure is reduced to a predetermined pressure. Is supplied.

  The second bottom piping 45 of the hot water storage tank 41 is connected to the inflow side of the water piping 22 </ b> A of the hot water supply heat exchanger 22 via the circulation pump 46. Further, an incoming water temperature detecting means 22B is installed on the inlet side of the water pipe 22A of the hot water supply heat exchanger 22, and a hot water temperature detecting means 22C is installed on the outlet side.

  The first upper pipe 47 of the hot water storage tank 41 is connected to the outflow side of the water pipe 22 </ b> A of the hot water supply heat exchanger 22 through a three-way valve 48. The third bottom piping 49 of the hot water storage tank 41 is connected to the three-way valve 48.

  The second upper pipe 50 of the hot water storage tank 41 is connected to a kitchen or a faucet such as a bathroom or a bath terminal (not shown).

  Next, the hot water storage operation of the heat pump hot water supply apparatus in the first embodiment of the present invention will be described with reference to the flowchart of FIG.

  First, when the user opens the faucet, the hot water is discharged from the second upper pipe 50, and when the amount of remaining hot water in the hot water storage tank 41 decreases, the compressor 21 is activated and the heat pump cycle 20 starts operation (step 1).

  Next, the incoming water temperature detecting means 22B detects the incoming water temperature, and the regenerator temperature detecting means 25A detects the regenerator temperature (step 2).

  Next, it is determined whether the incoming water temperature is equal to or higher than a predetermined temperature, that is, a high incoming water temperature region (step 3).

  If it is determined that the temperature is high, the first on-off valve 28 is opened, the second on-off valve 33 is closed, the third on-off valve 35 is closed, 4 is set to open (step 4).

  The first expansion valve 23 is set to fully open, and the second expansion valve 29 is set to open (an opening based on a predetermined control).

  The refrigerant compressed by the compressor 21 radiates heat in the hot water supply heat exchanger 22, passes through the first expansion valve 23 and the fourth on-off valve 24, is stored in the heat accumulator 25, and passes through the first on-off valve 28. As described above, after the pressure is reduced by the second expansion valve 29, the heat is absorbed by the evaporator 30 and is sucked into the compressor 21 in a gas state. The fan 31 is set to a rotational speed corresponding to the operating state of the compressor 21.

  Water from the hot water storage tank 41 is passed through the second bottom piping 45 of the hot water storage tank 41 by the circulation pump 46 and led to the water piping 22A of the hot water supply heat exchanger 22 to be heated to hot water, and the three-way valve 48 is turned on. Through the hot water storage tank 41.

  In the three-way valve 48, whether to connect to the first upper piping 47 of the hot water storage tank 41 or to the third bottom piping 49 of the hot water storage tank 41 is determined based on the outlet side of the water piping 22 </ b> A of the hot water supply heat exchanger 22. This is performed according to the temperature of the hot water temperature detecting means 22C installed in the hot water.

  When the amount of hot water in the hot water storage tank 41 is full, the compressor 21 and the circulation pump 46 are stopped, and the hot water storage operation is terminated. Therefore, even when the temperature is in the high incoming water temperature region, heat is stored in the heat accumulator 25, so that the refrigerant temperature at the outlet of the heat accumulator 25 does not rise so much and the operation of the compressor 21 can be continued.

  The regenerator 25 is filled with a high melting point latent heat storage agent 26 and a low melting point latent heat storage agent 27. For example, the melting point of the high melting point latent heat storage agent 26 is 50 ° C., and the melting point of the low melting point latent heat storage agent 27 is 30 ° C. Thus, when the refrigerant flows from the high melting point latent heat storage agent 26 to the low melting point latent heat storage agent 27, the refrigerant temperature at the outlet of the heat storage unit 25 can be maintained at about 30 ° C. even if the incoming water temperature becomes 50 ° C.

  If it is determined in step 3 that the incoming water temperature is lower than the predetermined temperature, that is, if it is determined that it is not in the high incoming water temperature range, is the temperature of the regenerator 25 equal to or higher than the predetermined temperature, that is, whether heat is stored in the regenerator 25 Judgment is made (step 5).

  When the temperature is equal to or higher than the predetermined temperature, it is determined whether the heat is stored and the heat is radiated. Therefore, the first on-off valve 28 is closed, the second on-off valve 33 is opened, the third on-off valve 35 is opened, and the fourth on-off valve 24 is closed (step 6). The first expansion valve 23 is set to open (an opening based on a predetermined control), and the second expansion valve 29 is set to open (an opening based on a predetermined control).

  The refrigerant compressed by the compressor 21 dissipates heat in the hot water supply heat exchanger 22, and one refrigerant passes through the second on-off valve 33 and the first bypass circuit 32 and is decompressed by the second expansion valve 29. Thereafter, the heat is absorbed by the evaporator 30, and the other refrigerant is decompressed by the first expansion valve 23, and then absorbed by the heat accumulator 25, passes through the second bypass circuit 34, and flows through the evaporator 30. It merges with the refrigerant and is sucked into the compressor 21 in a gas state.

  Since the heat accumulator 25 also acts as an evaporator, the fan 31 is set at a lower rotational speed than the normal rotational speed.

  Water from the hot water storage tank 41 is passed through the second bottom piping 45 of the hot water storage tank 41 by the circulation pump 46 and led to the water piping 22A of the hot water supply heat exchanger 22 to be heated to hot water, and the three-way valve 48 is turned on. Through the hot water storage tank 41.

  In the three-way valve 48, whether to connect to the first upper piping 47 of the hot water storage tank 41 or to the third bottom piping 49 of the hot water storage tank 41 is determined based on the outlet side of the water piping 22 </ b> A of the hot water supply heat exchanger 22. This is performed according to the temperature of the hot water temperature detecting means 22C installed in the hot water.

  When the amount of hot water in the hot water storage tank 41 is full, the compressor 21 and the circulation pump 46 are stopped, and the hot water storage operation is terminated.

  When it is determined in step 5 that the temperature of the heat accumulator 25 is lower than the predetermined temperature, if there is no heat remaining in the heat accumulator 25, the first on-off valve 28 is closed, the second on-off valve 33 is opened, and the third on-off The valve 35 is closed and the fourth on-off valve 24 is closed (step 7).

  The first expansion valve 23 is set to be fully closed, and the second expansion valve 29 is set to be open (an opening based on a predetermined control).

  The refrigerant compressed by the compressor 21 dissipates heat in the hot water supply heat exchanger 22, passes through the second on-off valve 33 and the first bypass circuit 32, and is decompressed by the second expansion valve 29. Heat is absorbed at 30 and is sucked into the compressor 21 in a gas state. The fan 31 is set to a rotational speed corresponding to the operating state of the compressor 21.

  Water from the hot water storage tank 41 is passed through the second bottom piping 45 of the hot water storage tank 41 by the circulation pump 46 and led to the water piping 22A of the hot water supply heat exchanger 22 to be heated to hot water, and the three-way valve 48 is turned on. Through the hot water storage tank 41.

  In the three-way valve 48, whether to connect to the first upper piping 47 of the hot water storage tank 41 or to the third bottom piping 49 of the hot water storage tank 41 is determined based on the outlet side of the water piping 22 </ b> A of the hot water supply heat exchanger 22. This is performed according to the temperature of the hot water temperature detecting means 22C installed in the hot water.

  When the amount of hot water in the hot water storage tank 41 is full, the compressor 21 and the circulation pump 46 are stopped, and the hot water storage operation is terminated.

  As the boiling operation time elapses, a hot water mixed layer is formed at the portion where the hot water in the hot water storage tank 41 comes into contact with water, and that layer expands to the lower part of the hot water storage tank 41. The temperature of the water flowing into the hot water supply heat exchanger 22 through the circulation pump 46 increases.

  In this case, the refrigerant temperature at the outlet of the hot water supply heat exchanger 22 also rises, but since the heat is accumulated in the heat accumulator 25, the refrigerant 21 at the outlet of the heat accumulator 25 can continue to operate without increasing so much.

  The regenerator 25 is filled with a high melting point latent heat storage agent 26 and a low melting point latent heat storage agent 27. For example, the melting point of the high melting point latent heat storage agent 26 is 50 ° C., and the melting point of the low melting point latent heat storage agent 27 is 30 ° C. Thus, when the refrigerant flows from the high melting point latent heat storage agent 26 to the low melting point latent heat storage agent 27, the refrigerant temperature at the outlet of the heat storage unit 25 can be maintained at about 30 ° C. even if the incoming water temperature becomes 50 ° C.

  As described above, in the heat pump hot water supply apparatus of the present embodiment, when the incoming water temperature is high, in the normal heat pump cycle, the 22 outlet temperature of the hot water supply heat exchanger also rises, and the hot water supply heat exchanger 22 and the evaporator 30 Since the refrigerant hold amount decreases, the high pressure tends to increase.

  However, by storing the heat of the refrigerant in the heat accumulator 25 and cooling the refrigerant that has exited the hot water supply heat exchanger 22 as in the present invention, the refrigerant enthalpy is reduced and its density is increased. Since the degree of dryness at the inlet of the evaporator 30 also decreases and the refrigerant hold amount of the evaporator increases, even if the incoming water temperature is high, the heat pump cycle can be operated safely without increasing the high pressure.

  Accordingly, since the compressor 21 can be continuously operated without increasing the high pressure even when the incoming water temperature rises, the hot water can be stored up to the lower part of the hot water storage tank 41, and the capacity of the hot water storage tank 41 can be effectively used. .

  Further, when recovering the amount of heat stored in the heat accumulator 25, the heat accumulator 25 is operated in parallel with the evaporator 30 and is collected as another evaporator, so that the evaporation capacity is increased and a more efficient operation can be performed. effective.

  In this embodiment, the case where carbon dioxide is used as the refrigerant has been described. However, other refrigerants such as R410A refrigerant and HC refrigerant may be used as the refrigerant.

  Further, in the present embodiment, the case where the heat accumulator is filled with two types of latent heat storage agents having different melting points is described, but three or more types of latent heat storage agents having different melting points may be filled.

  Furthermore, although this Embodiment demonstrated using the heat pump hot-water supply apparatus provided with the heat pump cycle 20, you may use two or more heat pump cycles.

  As described above, the heat pump hot water supply apparatus according to the present invention can easily heat hot water to a high temperature while reducing the discharge pressure of the compressor of the refrigerant circuit. It can also be applied to uses such as heating that uses heat.

The circuit block diagram of the heat pump hot-water supply apparatus in the 1st Embodiment of this invention Flow chart of on / off valve control of the heat pump water heater Configuration diagram of conventional heat pump water heater

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Heat pump cycle 21 Compressor 22 Heat exchanger for hot water supply 23 1st expansion valve 25 Heat accumulator 28 1st on-off valve 29 2nd expansion valve 30 Evaporator 32 1st bypass circuit 33 2nd on-off valve 34 2nd 2 bypass circuit 35 third on-off valve 41 hot water storage tank

Claims (7)

A compressor, a hot water supply heat exchanger, a first expansion valve, a heat accumulator, a first on-off valve, a second expansion valve, and an evaporator are connected in an annular shape by piping, and the first expansion valve and the heat storage And a first bypass circuit that bypasses the first on-off valve and is provided with a second on-off valve, a pipe between the heat accumulator and the first on-off valve, the compressor, and the evaporator A heat pump comprising a heat pump cycle having a second bypass circuit provided with a third on-off valve and a hot water storage tank for storing hot water heated by using the heat pump cycle. Hot water supply device. The hot water supply temperature detection means for detecting the temperature of the water side inlet of the hot water supply heat exchanger and the heat storage temperature detection means for detecting the temperature of the heat storage device are provided, and the water supply temperature detected by the water supply temperature detector is provided. Depending on the temperature of the water-side inlet of the heat exchanger and the temperature of the heat accumulator detected by the heat accumulator temperature detecting means, the first on-off valve, the second on-off valve, and the third on-off valve The heat pump hot-water supply apparatus according to claim 1, wherein opening and closing is controlled. The heat pump according to claim 2, wherein when the first on-off valve is closed, the second on-off valve is open, and the third on-off valve is in an open state, the capacity of the evaporator is reduced. Hot water supply device. The heat pump hot-water supply device according to claim 2 or 3, wherein the heat storage device is filled with a latent heat storage agent. The heat pump hot-water supply apparatus according to claim 2 or 3, wherein the heat accumulator is filled with a plurality of latent heat storage agents having different melting points. 6. The heat pump hot water supply apparatus according to claim 5, wherein the refrigerant flows from the latent heat storage agent having a high melting point to the latent heat storage agent having a low melting point. The heat pump hot water supply apparatus according to any one of claims 2 to 6, wherein the refrigerant used in the heat pump cycle is carbon dioxide, and the high pressure side is operated in a state exceeding a critical pressure.

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