JP6228828B2 - Water heater - Google Patents

Description

  The present specification relates to a hot water supply apparatus.

  Patent Document 1 includes a compressor, a condenser, an expansion mechanism, and an evaporator, a heat pump that heats water by heat radiation from the refrigerant in the condenser, a capacity of 300 liters or more, and a heat pump A hot water supply device is disclosed that includes a tank that stores heated water and a control device that controls the operation of the heat pump.

JP 2013-204842 A

  When a large tank having a capacity exceeding 300 liters is used as in the hot water supply apparatus of Patent Document 1, once the water in the tank is boiled, the amount of hot water used for one day can be covered. For this reason, the water in the tank by the heat pump may be boiled once a day, for example, in the midnight time zone when the power rate is low. However, when installing such a large tank, the tank is usually anchored to a concrete foundation and installed on the ground in order to secure earthquake resistance against earthquakes. For this reason, it is necessary to embed pipes in the ground, to place concrete as a foundation, and to fix anchors, which requires a lot of labor for installation work. In order to further improve the workability of the hot water supply device, it is preferable to use a small tank that can ensure the seismic strength without anchoring to the foundation.

  For example, if a small tank having a capacity of 25 liters or less is used, the tank does not become so heavy when full of water, so that sufficient earthquake resistance can be ensured even with a simple installation structure. However, when a small tank having a capacity of 25 liters or less is used, the tank runs out every time hot water is supplied several times, and the tank needs to be boiled each time. Therefore, in the case of using a small tank, it is extremely important to shorten the time required for boiling the tank as much as possible in order to ensure user convenience.

  The present specification provides a technique for solving the above problems. In this specification, in the hot water supply apparatus provided with a tank and a heat pump, the technique which can improve workability | operativity more is ensured, ensuring a user's convenience.

Water heater taught in the present specification includes a compressor, a condenser, an expansion mechanism, and an evaporator, a heat pump for heating water by heat radiation from the refrigerant in the condenser, heated by the heat Toponpu A tank for storing water and a control device for controlling the operation of the heat pump are provided. In the hot water supply device, when the control device starts heating the water by the heat pump, if the compressor stop time does not reach the reference time, the compressor is started by the first starting method in which the rotation speed rises quickly. When the stop time of the compressor exceeds the reference time, the compressor is started by the second starting method in which the rotation speed rises slowly.

In the hot water supply device described above, when the heating of the water by the heat pump is started, the start method of the compressor is switched according to the stop time of the compressor. When starting a compressor that has been stopped for a long time, since the refrigeration oil is dissolved in the refrigerant in a state of higher viscosity than during operation, if the number of revolutions of the compressor is increased from the start, only the refrigerant is compressed into the compressor. Sucked into. At this time, since the refrigerating machine oil stays in the pipe, the refrigerating machine oil in the compressor becomes insufficient. For this reason, conventionally, when starting a stopped compressor, the rotational speed of the compressor is gradually increased. However, if the time has not elapsed since the compressor was shut down, the viscosity of the refrigeration oil is not likely to increase. Such a problem does not occur. Therefore, in the above-described hot water supply apparatus, when the compressor stop time does not reach the reference time, the compressor is started by the first starting method in which the rise of the rotational speed is fast. Thereby, the heating rate of water by the heat pump can be improved, and the time required for boiling the tank can be shortened. Further, in the above hot water supply apparatus, when the compressor stop time exceeds the reference time, the compressor is started by the second starting method in which the rise of the rotational speed is slow. This can prevent problems such as poor lubrication in the compressor of the heat pump.

The hot water supply device further includes a refrigerant temperature detection unit that detects the temperature of the refrigerant, and the temperature of the refrigerant detected by the refrigerant temperature detection unit when the control device starts heating the water by the heat pump is an upper limit. When the refrigerant temperature is exceeded, even if the compressor stop time exceeds the reference time, the compressor is started by the first starting method.

In the heat pump, even if the compressor is stopped for a long time, if the temperature of the refrigerant is kept high during that time, the viscosity of the refrigerating machine oil is maintained in a low state, and there is no fear that the refrigerating machine oil in the compressor will be insufficient. Conceivable. For this reason, in the hot water supply apparatus described above, when the temperature of the refrigerant detected by the refrigerant temperature detection means exceeds the upper limit refrigerant temperature when the heating of the water by the heat pump is started, the compressor stop time exceeds the reference time. Even in this case, the compressor is started by the first starting method in which the rotational speed rises quickly. By setting it as such a structure, the heating rate of the water by a heat pump can be improved, and the time required for boiling of a tank can be shortened.

In the hot water supply apparatus, when the control device starts heating the water by the heat pump, if the temperature of the refrigerant detected by the refrigerant temperature detection means falls below the lower limit refrigerant temperature, the compressor is turned on by the second starting method. It can be configured to start.

When the temperature of the refrigerant is lowered, the viscosity of the refrigerating machine oil becomes high, and the refrigerating machine oil may not easily return to the compressor. For this reason, in the hot water supply device described above, when the heating of the water by the heat pump is started, if the temperature of the refrigerant detected by the refrigerant temperature detecting means falls below the lower limit refrigerant temperature, the second start-up with a slow rise in the rotational speed Start the compressor in the same way. By adopting such a configuration, it is possible to prevent problems such as poor lubrication in the compressor of the heat pump.

Alternatively, the hot water supply device further includes an outside air temperature detecting unit that detects an outside air temperature, and the outside air temperature detected by the outside air temperature detecting unit when the control device starts heating the water by the heat pump is a reference. When the outside air temperature is exceeded, even when the compressor stop time exceeds the reference time, the compressor is started by the first starting method.

When the outside air temperature is high, such as in summer, the refrigerant is immediately heated by the outside air having a high temperature even when the compressor is stopped for a long time, and the melted refrigeration oil immediately rises in temperature and the viscosity is lowered. For this reason, in the hot water supply apparatus described above, when the outside air temperature detected by the outside air temperature detecting means exceeds the reference outside air temperature when starting the water heating by the heat pump, the compressor stop time exceeds the reference time. Even so, the compressor is started by the first starting method. By setting it as such a structure, the heating rate of the water by a heat pump can be improved, and the time required for boiling of a tank can be shortened.

In the hot water supply apparatus described above, the capacity of the tank may be 25 liters or less. In this case, since the weight of the tank when it is full is relatively light, sufficient earthquake resistance can be ensured even with a simple installation structure. For this reason, when installing the above-mentioned hot water supply equipment, it is not necessary to embed piping into the ground, place concrete under the ground, or fix anchors, which is necessary when installing a large tank on the ground. It becomes. According to said hot water supply apparatus, workability | operativity can be improved.

The hot water supply apparatus can be configured such that the weight of the tank is supported by a building wall.

In general, in order to ensure pressure resistance, the tank is often elongated. In this case, since the center of gravity of the tank is full when the tank is full, when the tank is installed on the ground, it is necessary to take measures to prevent the tank (or the casing housing the tank) from falling. According to the hot water supply apparatus described above, since the weight of the tank is supported by the wall of the building, it is not necessary to take measures to prevent the tank (or the casing containing the tank) from falling. The installation structure of the hot water supply device can be further simplified.

  The hot water supply apparatus can be configured to further include an auxiliary heat source device that heats water by burning fuel.

  According to the hot water supply apparatus described above, even when the user supplies hot water after the tank runs out until the tank is completely boiled, hot water is supplied at a desired temperature using the auxiliary heat source device. be able to. In the above hot water supply device, the time required to boil the tank can be shortened, so even when using an auxiliary heat source unit that is less energy efficient than the heat pump, the heat pump can be used for heating the water. As much as possible, high energy efficiency can be achieved.

  The above hot water supply apparatus can be configured such that the capacity of the tank is 10 liters or more.

  According to the hot water supply apparatus described above, the amount of hot water used by a general user at the same time in the bathroom or in the kitchen can be covered by hot water from the tank, except for hot water filling in the bathtub or shower.

  According to the hot water supply apparatus disclosed in the present specification, it is possible to further improve the workability while ensuring the convenience for the user.

It is a figure which shows typically the structure of the hot water supply apparatus 10 of an Example. In the hot-water supply apparatus 10 of an Example, it is a flowchart explaining the process which the controller 11 performs at the time of boiling operation. In the hot water supply apparatus 10 of an Example, it is a figure which shows the time-dependent change of compressor rotation speed and heat pump exit temperature at the time of starting a heat pump at low speed. In the hot water supply apparatus 10 of an Example, it is a figure which shows a time-dependent change of the compressor rotation speed and heat pump exit temperature at the time of starting a heat pump at high speed.

(Example)
As shown in FIG. 1, the hot water supply apparatus 10 includes a tank unit 20, an HP heat source unit 40, a gas heat source unit 50, and a controller 11.

  The HP heat source unit 40 includes a heat pump 40 a including a compressor 41, a condenser 43, an expansion valve 44, and an evaporator 45. In the heat pump 40a, the discharge side of the compressor 41, the refrigerant flow path 43a of the condenser 43, the expansion valve 44, the evaporator 45, and the suction side of the compressor 41 are sequentially connected by a refrigerant pipe 46. Circulates in this order. The refrigerant may be, for example, R744 (CO2 refrigerant) or R410A (HFC refrigerant). When the compressor 41 is driven in the heat pump 40a, gaseous high-temperature and high-pressure refrigerant is sent from the compressor 41 to the condenser 43. The refrigerant that has flowed into the condenser 43 is condensed by releasing heat into the water flowing through the water flow path 43 b to be in a liquid state, and is sent to the expansion valve 44. In the expansion valve 44, the liquid refrigerant is adiabatically expanded to a low temperature and a low pressure, and is sent to the evaporator 45. The refrigerant that has flowed into the evaporator 45 is vaporized by heat absorption from the outside air blown by the fan 45 a, becomes gaseous, and is sent to the compressor 41. Thus, in the HP heat source unit 40, water can be heated using outside air as a heat source. A refrigerant pipe 46 between the evaporator 45 and the compressor 41 is provided with a refrigerant thermistor 46a for detecting the refrigerant temperature.

  A defrosting path 47 is connected to the refrigerant pipe 46 of the HP heat source unit 40 between the condenser 43 and the expansion valve 44 and between the expansion valve 44 and the evaporator 45. In the defrosting path 47, a defrosting valve 47a is provided. In the heat pump 40a, frost may adhere to the surface of the evaporator 45. In such a case, when the compressor 41 is driven with the defrost valve 47a opened, a relatively high-temperature refrigerant that is not adiabatically expanded is sent from the condenser 43 to the evaporator 45. Frost adhering to the surface can be melted.

  A circulation forward path connection path 48 is connected to the inlet side of the water flow path 43b of the condenser 43, and a circulation return path connection path 49 is connected to the outlet side. A circulation pump 42 and an inlet-side thermistor 48a are provided in the circulation outward path connection path 48. The circulation return path connection path 49 is provided with an outlet-side thermistor 49a. The inlet-side thermistor 48 a detects the temperature of the water flowing into the water channel 43 b of the condenser 43. The outlet side thermistor 49 a detects the temperature of the water flowing out from the water flow path 43 b of the condenser 43.

  The tank unit 20 includes a tank 21 and a mixer 24. The tank 21 of this embodiment is a small tank having a capacity of 25 liters. The capacity of the tank 21 may be any capacity as long as it is 25 liters or less. Preferably, the capacity of the tank 21 is 10 liters or more. If the capacity of the tank 21 is 10 liters or more, the amount of hot water used by a general user at the same time in the bathroom or kitchen can be covered by the hot water from the tank 21 except for hot water filling in the bathtub or shower.

  A water supply path 22 for supplying tap water to the tank 21 is connected to the bottom of the tank 21. In the vicinity of the tap water inlet 22 a of the water supply path 22, a pressure reducing valve 23 is provided. The pressure reducing valve 23 adjusts the water supply pressure to the water supply path 22. A mixed water supply path 26 of the mixer 24 is connected to the downstream side of the pressure reducing valve 23 of the water supply path 22. In the mixed water supply path 26, a water supply control valve 26a, a water supply flow rate sensor 26b, and a water supply thermistor 26c are provided. The water supply control valve 26 a adjusts the flow rate of tap water flowing through the mixed water supply path 26. The water supply flow rate sensor 26 b and the water supply thermistor 26 c detect the flow rate and temperature of tap water flowing through the mixed water supply path 26. When the hot water in the tank 21 is depressurized or the water supply control valve 26a is opened, the downstream pressure of the pressure reducing valve 23 decreases. The pressure reducing valve 23 opens when the downstream pressure decreases, and tries to maintain the pressure at a predetermined pressure regulation value. For this reason, when the hot water in the tank 21 is depressurized or the water supply control valve 26a of the mixer 24 is opened, tap water is supplied thereto.

  In the water supply path 22, a drainage path 31 is connected to the downstream side of the connection portion of the mixed water supply path 26. A drain valve 32 is provided in the middle of the drain path 31. The drain valve 32 can be manually opened and closed. When the drain valve 32 is opened, the water in the tank 21 is drained to the outside through the drain path 31.

  One end of a circulation forward path 33 is connected to the bottom of the tank 21, and one end of a circulation return path 34 is connected to the upper part of the tank 21. The other end of the circulation outward path 33 is connected to the circulation outward path connection path 48 of the HP heat source unit 40, and the other end of the circulation return path 34 is connected to the circulation return path connection path 49. An outward thermistor 36 is provided in the circulation outward path 33. The forward path thermistor 36 detects the temperature of the water that has flowed out of the tank 21 into the circulation forward path 33. When the heat pump 40a of the HP heat source unit 40 is driven and the circulation pump 42 is further driven, water is sucked from the lower part of the tank 21 to the circulation forward path 33, and this water flows through the water flow path 43b of the condenser 43 and is heated. Then, it is returned to the upper part of the tank 21 through the circulation return path 34. In this way, the water in the tank 21 can be boiled by the heat pump 40a.

  A pressure release path 38 is connected in the middle of the circulation return path 34 of the tank unit 20, and a relief valve 38 a is provided in the pressure release path 38. The valve opening pressure of the relief valve 38 a is set slightly higher than the pressure regulation value of the pressure reducing valve 23. When pressure regulation of the pressure reducing valve 23 becomes impossible, the relief valve 38a is opened to prevent the pressure in the tank 21 from exceeding the pressure that can withstand pressure. An upper thermistor 39 is attached to the upper portion of the tank 21. The upper thermistor 39 detects the water temperature at the upper part of the tank 21. The tank unit 20 is also provided with an outside air temperature thermistor 35 that detects the outside air temperature.

  A hot water path 25 of the mixer 24 is connected to the upper portion of the tank 21. The warm water path 25 is provided with a warm water control valve 25a, a warm water flow rate sensor 25b, and a warm water thermistor 25c. The hot water control valve 25 a adjusts the flow rate of water flowing from the tank 21 to the hot water path 25. The hot water flow rate sensor 25 b detects the flow rate of water flowing from the tank 21 to the hot water path 25. The hot water thermistor 25 c detects the temperature of the water flowing through the hot water path 25. The warm water path 25 and the mixed water supply path 26 merge and are connected to the first mixing path 27. The first mixing path 27 is provided with a mixing thermistor 27 a that detects the temperature of the mixed water flowing through the first mixing path 27.

  The tank unit 20 includes a first hot water supply path 29. A hot water supply thermistor 29 a is provided in the first hot water supply path 29. A hot-water tap 60 is connected to the tip of the first hot water supply path 29. The hot-water tap 60 is arranged in a bathroom, a washroom, a kitchen, etc. (in FIG. 1, the plurality of hot-water taps 60 are represented by one). The middle of the first mixing path 27 and the middle of the first hot water supply path 29 are connected by a hot water supply bypass path 28. The hot water supply bypass path 28 is provided with a bypass control valve 28a. When the bypass control valve 28a is opened, the mixed water flowing through the first mixing path 27 flows to the hot water supply bypass path 28, and when the bypass control valve 28a is closed, the mixed water flowing through the first mixing path 27 is It flows to the second mixing path 51 of the gas heat source unit 50 described later.

  The gas heat source unit 50 includes a burner heat exchanger 52, a burner 53, and the like. The mixed water from the first mixing path 27 of the tank unit 20 flows into the burner heat exchanger 52 via the second mixing path 51. The second mixing path 51 is provided with an incoming water thermistor 51a, a hot water supply flow rate sensor 51b, and a water amount servo 51c. The incoming water thermistor 51a and the hot water supply flow rate sensor 51b detect the temperature and flow rate of the water flowing through the second mixing path 51, respectively. The water amount servo 51 c adjusts the flow rate of water flowing through the second mixing path 51. The gas combustion type burner 53 heats the burner heat exchanger 52. The water heated by the burner heat exchanger 52 flows into the first hot water supply path 29 of the tank unit 20 via the second hot water supply path 54. In the second hot water supply path 54, a can body thermistor 55 is provided near the outlet of the burner heat exchanger 52, and a hot water thermistor 56 is provided downstream thereof. A heat source bypass path 57 is connected between the downstream side of the water amount servo 51 c in the second mixing path 51 and the can body thermistor 55 and the hot water thermistor 56 in the second hot water supply path 54. A heat source unit bypass control valve 58 is provided at a connection portion between the second mixing path 51 and the heat source unit bypass path 57. By adjusting the opening degree of the heat source unit bypass control valve 58, a part of the water flowing through the second mixing path 51 flows into the heat source unit bypass path 57, and the flow rate of the water is adjusted.

  The controller 11 includes a CPU, a ROM, a RAM, and the like. Various operation programs are stored in the ROM. The RAM temporarily stores various signals input to the controller 11 and various data generated in the course of execution of processing by the CPU. In the controller 11, the CPU outputs drive signals to various devices such as the tank unit 20, the HP heat source unit 40, and the gas heat source unit 50 based on information stored in the ROM and RAM. A remote controller 13 is connected to the controller 11. The remote controller 13 is provided with a switch 16 for operating the hot water supply device 10, a liquid crystal display 17 for displaying an operation state of the hot water supply device 10, and the like, and information set by the remote control 13 is input to the controller 11. .

  In the hot water supply apparatus 10 of the present embodiment, the tank unit 20 and the gas heat source unit 50 are both installed so as to be supported on the outer wall of the building. In particular, in this embodiment, the capacity of the tank 21 is 25 liters, and the weight of the tank 21 when it is full is relatively light. Therefore, even if the weight of the tank 21 is supported by the building wall, the earthquake resistance is sufficient. Can be secured. When the small tank 21 is used as described above, it is not necessary to embed piping into the ground, to place concrete as a foundation, or to fix the anchor, which is necessary when installing the large tank on the ground. .

  Below, operation | movement of the hot-water supply apparatus 10 is demonstrated.

(Hot water operation)
In the hot water supply operation, the mixed water adjusted to the hot water supply set temperature by the mixer 24 was adjusted to a temperature lower than the hot water supply set temperature by the first hot water supply operation for supplying hot water from the hot water tap 60 through the hot water supply bypass path 28. One of the 2nd hot water supply operation which heats mixed water with gas heat source unit 50, and supplies hot water from hot-water tap 60 is performed.

  When the detected water temperature of the upper thermistor 39 of the tank 21 is equal to or higher than the first reference temperature (for example, the hot water set temperature + 5 ° C.) higher than the hot water set temperature set by the remote controller 13, the first hot water supply operation is performed. . In the first hot water supply operation, the controller 11 opens the bypass control valve 28a and fully closes the water amount servo 51c. The controller 11 adjusts the opening degree of the hot water control valve 25a and the opening degree of the water supply control valve 26a so that the water temperature detected by the mixing thermistor 27a becomes the hot water supply set temperature. The mixed water adjusted to the hot water supply set temperature flows through the first mixing path 27, and then hot water is supplied from the hot water tap 60 through the hot water supply bypass path 28 and the first hot water supply path 29.

  On the other hand, when the detected water temperature of the upper thermistor 39 is lower than the first reference temperature, the second hot water supply operation is performed. In the second hot water supply operation, the controller 11 fully closes the bypass control valve 28a and sets the water amount servo 51c to a predetermined opening. The controller 11 adjusts the opening degree of the hot water control valve 25a and the water supply control valve 26a so that the water temperature detected by the mixed thermistor 27a becomes a second reference temperature lower than the hot water supply set temperature (for example, the hot water supply set temperature −5 ° C.). Adjust the opening. The mixed water adjusted to the second reference temperature flows through the first mixing path 27, flows through the second mixing path 51 of the gas heat source unit 50, flows into the burner heat exchanger 52, and is heated by the burner 53. The heating capacity of the burner 53 is controlled so that the water temperature detected by the can body thermistor 55 provided at the outlet of the burner heat exchanger 52 is 60 ° C. or higher. Thereby, it can suppress that dew condensation water generate | occur | produces in piping. A part of the mixed water flowing through the second mixing path 51 flows into the second hot water supply path 54 through the heat source unit bypass path 57, and water of 60 ° C. or higher from the burner heat exchanger 52 and the second from the heat source unit bypass path 57. The water at the reference temperature is mixed, and the water at the hot water supply set temperature is sent to the first hot water supply path 29. In this way, the water adjusted to the hot water supply set temperature is supplied from the hot water tap 60 through the first hot water supply path 29. Thereby, even when the hot water stored in the tank 21 is completely consumed during the first hot water supply operation, the hot water adjusted to the hot water supply set temperature can be continuously supplied.

(Boiling operation)
In the boiling operation, the water in the tank 21 is heated by the heat pump 40 a to be hot hot water, and the hot water is stored in the tank 21. Below, the boiling operation which the hot-water supply apparatus 10 performs is demonstrated, referring FIG. When starting the boiling operation, the controller 11 executes the process of FIG.

  In Step S2, the controller 11 determines whether or not the stop time of the compressor 41 is less than a reference time (for example, 10 minutes). When the stop time of the compressor 41 is less than the reference time (in the case of YES in step S2), there is no possibility that the viscosity of the refrigerating machine oil in the evaporator 45 and the refrigerant pipe 46 is high, so that the heat pump 40a is started at high speed. The process proceeds to step S12. When the stop time of the compressor 41 exceeds the reference time (NO in step S2), the process proceeds to step S4.

  In step S4, the controller 11 determines whether or not the refrigerant temperature detected by the refrigerant thermistor 46a exceeds an upper limit refrigerant temperature (for example, 40 ° C.). The refrigerant temperature detected by the refrigerant thermistor 46a is the temperature of the refrigerant to be sent from the evaporator 45 to the compressor 41. When the temperature of the refrigerant is high to some extent, the viscosity of the refrigerating machine oil is not increased, and it is considered that no problem occurs even if the compressor 41 is rotated at a high speed. For this reason, when the refrigerant temperature detected by the refrigerant thermistor 46a exceeds the upper limit refrigerant temperature (YES in step S4), the process proceeds to step S12 in order to start the heat pump 40a at high speed. If the refrigerant temperature detected by refrigerant thermistor 46a is equal to or lower than the upper limit refrigerant temperature (NO in step S4), the process proceeds to step S6.

  In step S6, the controller 11 determines whether or not the refrigerant temperature detected by the refrigerant thermistor 46a is lower than a lower limit refrigerant temperature (for example, 20 ° C.). When the temperature of the refrigerant to be sent from the evaporator 45 to the compressor 41 is low to some extent, the viscosity of the refrigerating machine oil is high, and the refrigerating machine oil stays in the evaporator 45 and the refrigerant pipe 46 when the heat pump 40a is started at high speed. Therefore, there is a possibility that the refrigerating machine oil returning to the compressor 41 is insufficient. For this reason, when the refrigerant temperature detected by the refrigerant thermistor 46a is lower than the lower limit refrigerant temperature (YES in step S6), the process proceeds to step S10 in order to start the heat pump 40a at a low speed. If the refrigerant temperature detected by refrigerant thermistor 46a is equal to or higher than the lower limit refrigerant temperature (NO in step S6), the process proceeds to step S8.

  In step S8, the controller 11 determines whether or not the outside temperature detected by the outside temperature thermistor 35 exceeds a reference outside temperature (for example, 30 ° C.). When the outside air temperature is high such as in summer, the refrigerant is immediately heated and melted by the high temperature outside air if the refrigerant temperature is equal to or higher than the lower limit refrigerant temperature even if the compressor 41 is stopped for a long time. Since the temperature of the refrigerating machine oil also increases immediately and the viscosity decreases, it is considered that no problem will occur even if the compressor 41 is rotated at a high speed. For this reason, when the outside temperature detected by the outside temperature thermistor 35 exceeds the reference outside temperature (in the case of YES at step S8), the process proceeds to step S12 in order to start the heat pump 40a at high speed. When the outside air temperature detected by the outside air temperature thermistor 35 is equal to or lower than the reference outside air temperature (NO in step S8), the process proceeds to step S10 in order to start the heat pump 40a at a low speed.

  In step S10, the controller 11 starts the heat pump 40a at a low speed. Specifically, the controller 11 performs FF (feed forward) control of the rotation speed of the compressor 41 at a low rotation speed for a predetermined time, and then the water temperature detected by the outlet-side thermistor 49a is raised to the target boiling temperature. FB (feedback) control is performed on the rotational speed of the compressor 41 so as to approach. After step S10, the process proceeds to step S14.

  In step S12, the controller 11 starts the heat pump 40a at a high speed. Specifically, the controller 11 performs FF (feed forward) control of the rotation speed of the compressor 41 to a rotation speed set in advance corresponding to the water boiling target temperature. After step S12, the process proceeds to step S14.

  In step S <b> 14, the controller 11 drives the circulation pump 42. Thereby, the water sucked out from the lower part of the tank 21 is heated by the condenser 43 and returned to the upper part of the tank 21.

  In step S <b> 16, the controller 11 waits until the boiling of the tank 21 is completed. In the present embodiment, the controller 11 determines that the boiling of the tank 21 has been completed when the temperature detected by the forward thermistor 36 reaches the boiling target temperature. When the boiling of the tank 21 is completed (YES in step S16), the process proceeds to step S18.

  In step S <b> 18, the controller 11 stops the circulation pump 42. In step S20, the controller 11 stops the heat pump 40a. After the process of step S20 is performed, the process of FIG.

  3 and 4 show the rotation speed of the compressor 41 (compressor rotation speed) and the temperature of the water returned from the heat pump 40a to the tank 21 (HP outlet temperature) when the heat pump 40a is started at a low speed and when the heat pump 40a is started at a high speed. ) Over time. As shown in FIG. 3, when the heat pump 40a is started at a low speed, the rotational speed of the compressor 41 gradually increases, and the temperature of the water returned from the heat pump 40a to the tank 21 gradually approaches the boiling target temperature. In this case, even when the viscosity of the refrigeration oil is high, the heat pump 40a can be started while preventing poor lubrication in the compressor 41. On the other hand, as shown in FIG. 4, when the heat pump 40a is started at a high speed, the rotational speed of the compressor 41 quickly increases, and the temperature of the water returned from the heat pump 40a to the tank 21 also quickly reaches the boiling target temperature. Get closer to. In this case, the time required for boiling the tank 21 can be shortened.

  In the hot water supply apparatus 10 of this embodiment, when the stop time of the compressor 41 is not so long, the heat pump 40a is started at a high speed. When the stop time of the compressor 41 is not so long, the viscosity of the refrigerating machine oil is low, and even if the rotation speed of the compressor 41 is increased rapidly, the refrigerating machine oil quickly returns to the compressor 41, causing problems such as poor lubrication. It does not occur. Therefore, in such a case, the time required for boiling the tank 21 can be shortened by starting the heat pump 40a at a high speed.

  In the hot water supply apparatus 10 of the present embodiment, the heat pump 40a is started at a high speed when the refrigerant temperature exceeds the upper limit refrigerant temperature. When the refrigerant temperature is high, the viscosity of the refrigerating machine oil is low, and problems such as poor lubrication do not occur even if the rotation speed of the compressor 41 is rapidly increased. Therefore, in such a case, the time required for boiling the tank 21 can be shortened by starting the heat pump 40a at a high speed. On the contrary, in the hot water supply apparatus 10 of the present embodiment, when the refrigerant temperature is lower than the lower limit refrigerant temperature, the heat pump 40a is started at a low speed. When the refrigerant temperature is low, the viscosity of the refrigerating machine oil is high, and the refrigerating machine oil may not easily return into the compressor 41. Therefore, in such a case, it is possible to prevent problems such as poor lubrication in the compressor 41 by starting the heat pump 40a at a low speed.

  In the hot water supply apparatus 10 of the present embodiment, the heat pump 40a is started at a high speed when the refrigerant temperature is equal to or higher than the lower limit refrigerant temperature and the outside air temperature exceeds the reference outside air temperature. When the outside air temperature is high, such as in summer, even if the viscosity of the refrigerating machine oil is high to some extent, the refrigerant is immediately heated by the high temperature outside air and the viscosity is lowered, so that the compressor 41 does not cause poor lubrication. it is conceivable that. Therefore, in such a case, the time required for boiling the tank 21 can be shortened by starting the heat pump 40a at a high speed.

  As described above, starting the heat pump 40a at a high speed and shortening the boiling time of the tank 21 has a particularly advantageous effect when the tank 21 is small as in this embodiment. When the tank 21 is small, the tank 21 runs out of hot water several times, and it is necessary to raise the water each time. As described above, the convenience of the user can be ensured by starting the heat pump 40a at a high speed and reducing the boiling time of the tank 21. Further, when an auxiliary heat source device such as the gas heat source unit 50 is provided as in the present embodiment, hot water is supplied using the auxiliary heat source device after the tank 21 runs out of hot water and until the boiling of the tank 21 is completed. This can be done, but in that case the energy efficiency is reduced. As described above, by starting the heat pump 40a at a high speed and shortening the boiling time of the tank 21, even when using an auxiliary heat source device that is lower in energy efficiency than the heat pump 40a, the heat pump 40a in heating water is used. High energy efficiency can be achieved by increasing the utilization ratio as much as possible.

  As mentioned above, although the Example of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

DESCRIPTION OF SYMBOLS 10 Hot water supply apparatus 11 Controller 13 Remote control 16 Switch 17 Liquid crystal display 20 Tank unit 21 Tank 22 Water supply path 22a Tap water inlet 23 Pressure reducing valve 24 Mixer 25 Hot water path 25a Hot water control valve 25b Hot water flow rate sensor 25c Hot water thermistor 26 Mixed water supply path 26a Water supply control valve 26b Water supply flow sensor 26c Water supply thermistor 27 First mixing path 27a Mixing thermistor 28 Hot water supply bypass path 28a Bypass control valve 29 First hot water supply path 29a Hot water supply thermistor 31 Drainage path 32 Drainage valve 33 Circulation forward path 34 Circulation return path 35 Outside air temperature thermistor 36 Outward thermistor 38 Pressure release path 38a Relief valve 39 Upper thermistor 40 HP heat source unit 40a Heat pump 41 Compressor 42 Circulation pump 43 Condenser 43a Refrigerant flow path 43b Water flow path 44 Expansion valve 5 Evaporator 45a Fan 46 Refrigerant piping 46a Refrigerant thermistor 47 Defrost path 47a Defrost valve 48 Circulation forward path connection path 48a Inlet side thermistor 49 Circulation return path connection path 49a Outlet side thermistor 50 Gas heat source unit 51 Second mixing path 51a Incoming water thermistor 51b Hot water supply flow sensor 51c Water quantity servo 52 Burner heat exchanger 53 Burner 54 Second hot water supply path 55 Can body thermistor 56 Hot water discharge thermistor 57 Heat source machine bypass path 58 Heat source machine bypass control valve 60 Hot water tap

Claims (3)

A heat pump that includes a compressor, a condenser, an expansion mechanism, and an evaporator, and heats water by heat radiation from the refrigerant in the condenser;
A tank to store the heated water in the heat Toponpu,
Refrigerant temperature detecting means for detecting the temperature of the refrigerant ;
A hot water supply device comprising a control device for controlling the operation of the heat pump,
When the control device starts heating the water by the heat pump, if the stop time of the compressor is less than the reference time, the control device starts the compressor by the first starting method with a fast rise of the rotational speed, and When the stop time exceeds the reference time, start the compressor with the second starting method with a slow start of the rotational speed ,
When the control device starts heating the water by the heat pump, even when the refrigerant temperature detected by the refrigerant temperature detection means exceeds the upper limit refrigerant temperature, even if the compressor stop time exceeds the reference time A hot water supply device for starting the compressor by the first starting method . The control device starts the compressor by the second starting method when the temperature of the refrigerant detected by the refrigerant temperature detecting means falls below the lower limit refrigerant temperature when starting the heating of water by the heat pump. Water heater. A heat pump that includes a compressor, a condenser, an expansion mechanism, and an evaporator, and heats water by heat radiation from the refrigerant in the condenser;
A tank for storing water heated by a heat pump;
Outside temperature detecting means for detecting outside temperature;
A hot water supply device comprising a control device for controlling the operation of the heat pump,
When the control device starts heating the water by the heat pump, if the stop time of the compressor is less than the reference time, the control device starts the compressor by the first starting method with a fast rise of the rotational speed, and When the stop time exceeds the reference time, start the compressor with the second starting method with a slow start of the rotational speed,
When the controller starts heating the water by the heat pump, even when the outside temperature detected by the outside temperature detecting means exceeds the reference outside temperature, even when the compressor stop time exceeds the reference time, A hot water supply device that starts the compressor by the first starting method.

Images