JP2004354046A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water heater requiring a smaller installation space or mass and allowing the reheating of hot water in a bathtub. <P>SOLUTION: The heat pump water heater comprises a heat pump circuit consisting of a compressor, a first heat exchanger for heat exchange between refrigerant discharged from the compressor and water introduced from a water pipe connected to a water supply pipe, a pressure reducer for reducing the pressure of the refrigerant from the first heat exchanger and a second heat exchanger provided between the pressure reducer and the compressor, a hot water supply tank for storing hot water heated via the first heat exchanger, a mixing means for mixing the hot water introduced from the water pipe and heated via the first heat exchanger with the hot water stored in the hot water supply tank, and a function for operating the heat pump circuit without using the hot water in the hot water supply tank when filling the bathtub with the hot water to fill the bathtub with the hot water from the first heat exchanger. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a water heater using a heat pump circuit.

  Conventional water heaters have a combustion type water heater that burns gas, etc. without having a hot water tank and boil water instantaneously with the strong combustion heat to supply hot water, and a large capacity hot water tank. There have been electric water heaters that store a large amount of hot water heated by an electric heater during the night in a hot water storage tank using nighttime electric power that is cheap at night and use the hot water stored in the hot water storage tank during the day.

  However, recently, heat pump water heaters, which are said to be 300 to 500% more energy efficient than electric water heaters, have begun to spread. The heat pump water heater uses a change in the state of the refrigerant as a heat source, so it is several times more energy efficient than electric heater heating, and does not burn gas etc., so it is said to be an environmentally friendly water heater that does not emit CO2. . However, since there is no strong heat as when burning gas, etc., a large-capacity hot water storage tank is provided like an electric water heater, and hot water is used at night by a heat pump circuit using cheap electric power at night. It was common to store in a hot water tank and use the stored hot water during the day. Therefore, in a conventional heat pump water heater, a heat pump circuit and a hot water storage tank for storing a large amount of hot water boiled by the heat pump circuit are provided as separate devices, respectively, and connected by piping or the like to function as a water heater.

  As an example of this, a heat pump water heater described in Japanese Patent Application Laid-Open No. 9-126546 is known. It has a heat pump circuit composed of a compressor, a condenser, a decompression device, and an evaporator, and a large-capacity hot water storage tank. Water is supplied from a lower part of the hot water storage tank to a water heat exchanger serving as a condenser of the heat pump circuit via a circulation pump. A pipe is connected, and a hot water pipe is connected to the outlet of the water heat exchanger and the upper part of the hot water storage tank to provide a boiling circuit.

  Then, an energy-efficient heat pump circuit is operated by using inexpensive electric power at night, and the water in the hot water tank is gradually circulated by the circulation pump while being gradually heated to a predetermined hot water temperature by the water heat exchanger. The operation of the heat pump circuit is stopped by detecting that the hot water temperature has been reached by the temperature detector.

  During the day, when hot water is used at the terminal used, hot water taken out from the upper part of the hot water tank and tap water are mixed at a mixing valve and supplied at an appropriate temperature.

  When the temperature of the hot water tank drops, the hot water supply path is not described in detail, but it is described that the hot water in the hot water tank is reheated by a water heat exchanger and a heater and supplied to the terminal used. I have.

JP-A-9-126747

  However, considering that the hot tub is filled with hot water stored in the hot tub, the capacity of the hot tub becomes close to 200L as in the case of the bathtub, and 500L is required if there is some margin for using other hot water. There is also. If hot water is stored to the full capacity of the hot water storage tank, its mass will exceed 200 kg to 500 kg. Therefore, the heat pump water heater has been subjected to foundation work to make the ground solid, and it could not be installed unless the installation space was large enough.

  Furthermore, boiling a large amount of hot water requires a large amount of energy, and storing it as a high-temperature hot water increases the difference from the outside air temperature and increases the heat loss due to heat radiation. Was supposed to use.

  For this reason, it could not be installed in a narrow place such as a veranda of an apartment or a condominium or a place with insufficient strength.

  In addition, conventional heat pump water heaters use low electricity rates at night, operate the heat pump circuit at night to make hot water and store it in a hot water tank, and store it in a hot water tank during the day without operating the heat pump circuit. Because they basically use hot water, they sometimes run out of hot water in the hot water storage tank, so they could not be boiled immediately and run out of hot water. In the heat pump water heater described in the above-mentioned Japanese Patent Application Laid-Open No. 9-126747, hot water is stored using nighttime power similarly to an electric water heater, and an additional cooking operation is performed when the amount of hot water is insufficient. It is auxiliary.

  In addition, heat is radiated from the surface of the hot water tank to store a large amount of hot water whose temperature is higher than the outside air temperature, resulting in waste of energy. Needed.

  An object of the present invention is to provide a hot water heater that requires a small space and a small mass for installation, and is capable of following the hot water in a bathtub.

  The object is to provide a compressor, a first heat exchanger for exchanging heat between refrigerant discharged from the compressor and water introduced from a water pipe connected to a water supply pipe, and a first heat exchanger. A pressure reducing device for reducing the pressure of the refrigerant, a heat pump circuit having a second heat exchanger provided between the pressure reducing device and the compressor, a hot water supply tank for storing hot water heated by the first heat exchanger, Mixing means for mixing hot water introduced from the water pipe and heated via the first heat exchanger with hot water stored in the hot water tank, and using hot water in the hot water tank when hot water is supplied to the bathtub. This is achieved by operating the heat pump circuit without performing the operation and pouring hot water from the first heat exchanger into the bathtub.

  According to the present invention, it is possible to provide a water heater that requires a small space and a small mass for installation, and that can follow the hot water in the bathtub and cook.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of a heat pump water heater according to the present invention.

  First, the refrigeration cycle will be described. Each device is connected by a refrigerant pipe, in which a refrigerant is sealed and sealed to constitute a heat pump circuit 10. In order to realize a large capacity required for hot water supply, another heat pump circuit 10a is provided. And two heat pump circuits. In the present embodiment, the water heater is constituted by two heat pump circuits, but one circuit or three or more circuits may be used depending on the performance and hot water supply capacity of the compressor and the heat exchanger.

  The refrigerant (carbon dioxide) compressed by the compressor 1 and the compressor 1a flows into the heat exchanger 2. The heat exchanger 2 incorporates condensers 3 and 3a for condensing the refrigerant, a water heat exchanger 11 for boiling hot water and a bath water heat exchanger 44. The refrigerant flowing out of the heat exchanger 2 is decompressed by the operation of the decompression device 5 and the decompression device 5a, and becomes a low-temperature low-pressure refrigerant. Then, in the evaporator 6 and the evaporator 6a, heat is absorbed from the blower 9 and the outside air blown by the blower 9a, and is sucked into the compressor 1 and the compressor 1a again through the accumulator 7 and the accumulator 7a. .

  Reference numerals 8 and 8a denote bypass valves. By opening the bypass valves, high-pressure and high-pressure refrigerant discharged from the compressor 1 and the compressor 1a is passed through the evaporators 6 and 6a, so that frost adhered to the evaporators 6 and 6a. Is melted (defrost control). The timing of this defrost control may be simultaneous for the two refrigerant circuits or may be shifted. In the case of shifting, there is an effect that hot water can be supplied without interruption, though the capacity is slightly lowered.

  Next, a water supply circuit of a water circulation circuit 22 that takes in water from the water pipe 16 and directly supplies hot water to the user side via the heat exchanger 2 or circulates water inside to raise the temperature to a predetermined temperature as described later. Will be described.

  In the water circulation circuit 22, the heat exchanger 2, the pressure reducing check valve 17, the flow sensor 21, the check valves 48 and 49, the hot water tank 13, the circulation pump 15, the hot water from the hot water tank 13 and the water heat exchanger 11 A mixing valve 61 for mixing hot water, a mixing valve 62 for mixing hot water from the mixing valve 61, and a flow control valve 63 for adjusting the flow rate of hot water are connected by a water pipe.

  The bathtub water circuit includes the heat exchanger 2, the pouring solenoid valve 51, the check valve 50, the water level sensor 60, and the circulation pump 46 for the bathtub.

  The heat pump water heater according to the present embodiment is a small and lightweight water heater without using a large-sized hot water storage tank as in the related art. That is, in the water heater that heats the hot water of the heat pump circuit 10 and the water of the water circulation circuit 22 with the water heat exchanger 11 to boil the water, the water introduced from the water supply pipe 16 is used by the water heat exchanger 11. By adopting an instantaneous system in which the temperature is raised and hot water is directly supplied to the use terminal 27, a conventional large-sized hot water storage tank can be eliminated. In addition, since the heat of condensation cannot be generated enough to heat the water until the pressure condition immediately after the start of the operation of the heat pump circuit 10 is stabilized, the rising time is short of the hot water stored in the hot water supply tank 13. By mixing the water from the water heat exchanger 11 and supplying hot water, the hot water supply tank 13 can be downsized while maintaining the set temperature. Then, when the operation of the heat pump circuit 10 is stabilized and the hot water at the set temperature is brought to a boiling state, the use of the hot water stored in the hot water supply tank 13 is stopped and the hot water is directly supplied. The details will be described below.

  The supply of water to the heat pump water heater will be described. The water supplied from the water supply pipe 16 flows into the pressure reducing check valve 17, one of which is connected to the hot water supply tank 13 via the water supply pipe 19 and the other is connected to the water pipe connected to the water heat exchanger 11. Through the heat exchanger 2. Hot water is supplied to the use terminal 27 at a set temperature through the mixing valves 61 and 62 and the flow control valve 63.

  The heat pump water heater shown in the present embodiment basically assumes an instantaneous water heater that raises the water supplied from the water supply pipe 16 to a temperature set by the user by the heat exchanger 2 and supplies the water to the use terminal 27. I have. Therefore, if the capacity of the refrigeration cycle is high or if the performance of the water heat exchanger 11 is high, it is not necessary to provide the hot water supply tank 13. For this reason, there is a possibility that the water heater will be drastically more compact than a conventional electric water heater that takes up weight and installation space.

  However, the hot water supply temperature may not reach the set temperature because the temperature of the supplied water is low, the refrigeration cycle is not stable, and the heat exchanger 2 is not sufficiently heated.

  Therefore, in this embodiment, the minimum required hot water supply tank 13 is installed, and the hot water stored in the hot water supply tank 13 is used supplementarily until the temperature of the water output from the heat exchanger 2 reaches the set temperature. This is to secure the hot water supply temperature at the use terminal 27.

  In some cases, the temperature of the hot water output from the heat exchanger 2 may not rise forever. In this case, when the use of hot water at the use terminal 27 is interrupted, hot water of a predetermined high temperature is stored in the hot water supply tank 13 to ensure the supply of hot water at the set temperature when the next hot water is used. Can be. The operation of each unit will become gradually clearer from the following description.

  As described above, immediately after the heat pump circuit operation is started, when the temperature of the hot water coming out of the heat exchanger 2 (water heat exchanger 11) is not sufficiently increased, the mixing valve 61 is used to supplement the hot water in the hot water supply tank 13. Is a valve for supplying hot water having a set temperature by mixing to the use terminal 27. The mixing valve 61 and the hot water supply tank 13 are connected by a hot water supply pipe 20.

  When the temperature of the hot water supplied from the mixing valve 61 is higher than the set temperature, the mixing valve 62 has a function of lowering the hot water temperature to the set temperature by mixing with the water supplied from the water supply pipe 16. are doing.

  Further, the flow rate adjusting valve 63 is a valve having a function of regulating the flow rate so that the hot water supply amount does not exceed a predetermined total amount.

  In addition, each part includes a feed water temperature sensor 52, a water heat exchanger outlet water temperature sensor 53, a water temperature sensor 54 for measuring the temperature of the mixed hot water in the hot water supply tank and the water heat exchanger outlet water, and a tap water for measuring the final tap water temperature. A temperature sensor 55, a tank temperature sensor 56 (a, b, c) for measuring the amount of remaining hot water in the hot water supply tank 13, and an evaporator temperature sensor for measuring an intermediate temperature between the evaporators 6, 6a on the refrigeration cycle side. Suction temperature sensors 59, 59a for sensing the suction temperature of the compressor 1 are arranged at 58, 58a.

  The water circulation circuit 22 including the heat pump circuits 10, 10a, the hot water supply tank 13, and other devices are housed in a box 23 described later.

  As the terminal 27 to be used, a faucet 24 in a kitchen or the like, a shower 25 in a bathroom, a bathtub 26 separated by a pouring solenoid valve 51 and a check valve 50, and the like are provided. The check valve 50 is a valve for preventing the hot and cold water supplied from the water supply pipe 16 from mixing with the hot and cold water in the bathtub 26 for sanitary reasons. In this embodiment, although not particularly specified, a water terminal is attached to each terminal as needed.

  The heat pump water heater according to the present embodiment has such a configuration and performs the operation described below. It is said that heat pump water heaters are 300 to 500% more energy efficient than electric water heaters. The heat pump circuit 10 is used to supply hot water directly to the terminal used, as in an instant water heater. However, as described above, the heat pump circuit 10 can sufficiently supply the heat of condensation required to heat the water in the water heat exchanger 11 immediately after the operation is started and until the heat pump circuit is stabilized. Therefore, warm water cannot be directly supplied to the use terminal 27. In the heat pump water heater of the present embodiment, high-temperature hot water stored in a small-capacity hot water supply tank 13 is supplementarily supplied and used for a few minutes of its rise.

  First, the capacity of the hot water supply tank 13 will be described. Except in extreme cases, the amount of water in the shower at ordinary households is 11.8 liters / minute, the kitchen is 8.5 liters / minute, the toilet is 7.5 liters / minute, and the continuous use time But the shower lasts 9.7 minutes and the kitchen lasts 13.4 minutes. If the simultaneous use is not considered, the required continuous hot water supply is about 114 liters. The hot water supply temperature is assumed to be 40 ° C., the temperature of hot water stored in the hot water supply tank 13 is assumed to be 60 ° C., which is said to be the temperature at which Salmorena bacteria and the like are killed, and the temperature of water supplied from the heat exchanger 2 is considered in the worst case. And 8 ° C. The amount of hot water that must be stored in the hot water supply tank 13 under these conditions is approximately 70 liters. However, since the temperature of the water supplied from the heat exchanger 2 cannot always be considered to be 8 ° C., if the temperature is about 18 ° C., which is 10 ° C. higher than this, the capacity of the hot water supply tank 13 only needs to be 60 liters.

  Further, assuming that the size of an outdoor unit of a packaged air conditioner currently on the market is acceptable for a household water heater, the height is about 1.4 m, the width is about 0.9 m, and the depth is about 0.3 m. Is a cylindrical shape, and the hot water supply tank 13 is housed in the box of the outdoor unit, the maximum allowable size is a diameter of the hot water supply tank 13 of 0.3 m and a height of 1.4 m. is there. This capacity is 0.1 cubic meters (100 liters).

  In summary, the hot water storage capacity of the hot water supply tank 13 is preferably in a range of 60 liters to 100 liters. When the hot water storage capacity of the hot water supply tank 13 falls within this range, the outdoor unit can be housed in a single box, such as a package air conditioner or a room air conditioner, as long as the use of the hot water is not hindered as described above. Can be. That is, the hot water supply tank 13 can be housed in one housing together with the compressor 1, the outdoor heat exchanger 6, the water heat exchanger 11, and the pressure reducing device 5, which are main components.

  By the way, in a refrigeration cycle using a CFC-based Freon refrigerant, 60 ° C. is almost the temperature at which the refrigerant is heated to the maximum. However, when carbon dioxide (CO 2) is used as a refrigerant, the hot water temperature can be further increased. The amount of hot water stored in hot water supply tank 13 may be reduced by an amount corresponding to the rise of.

  When a terminal other than the bath 26 is used, the flow sensor 21 detects the use of the terminal, starts the compressor 1 and starts the operation of the heat pump circuit 10. At the initial stage of the operation, the heat pump circuit 10 is still in the rising state, and thus the hot water supply operation using the hot water supply tank 10 is performed. The water guided from the water supply pipe 16 reaches the lower part of the hot water supply tank 13 via the pressure reducing valve 17 and the water supply pipe 19. In the hot water supply tank 13, water is supplied from the lower part thereof, and the hot water stored in the upper part of the hot water supply tank 13 is pushed out to the hot water supply pipe 20 by the water pressure.

  On the other hand, the water from the water supply pipe 16 is divided into a water circuit flowing to the water heat exchanger 11 to heat the water by the refrigeration cycle 10. The temperature is sensed by a temperature sensor 54 so as to reach a temperature set by a mixing valve 61 for mixing the hot water from the hot water supply tank 13 and the hot water from the water heat exchanger 11, and the hot water from the hot water storage tank 13 and the refrigeration cycle 10 It is adjusted by the amount of water from the water heat exchanger 11 which is more heated. In the early stage of the operation, the amount of hot water from the hot water supply tank 13 is large because the water passing through the water heat exchanger 11 is not sufficiently warmed, and the amount of water flowing through the water heat exchanger 11 is small ( Mixed operation mode). Here, when the amount of water flowing through the water heat exchanger 11 is reduced in the initial stage of operation, the temperature can be rapidly increased because of the small amount of water.

  In this mixing operation mode, if the temperature of the hot water of the terminal 27 in use is too high (when the temperature is equal to or higher than the set value), the mixing valve 62 is opened and the water from the water supply pipe 16 is mixed to adjust the hot water temperature.

  When the operation continues, the heat pump circuit 10 gradually starts to stabilize, the temperature of the hot water discharged from the water heat exchanger 11 also becomes high, and the mixing valve mixes the hot water from the hot water supply tank 13 and the hot water from the water heat exchanger 11. 61 gradually narrows out the hot water from the hot water supply tank 13, and when the hot water temperature from the water / refrigerant heat exchanger 11 reaches the set temperature, completely closes the hot water from the hot water supply tank 13 and heats the hot water from the heat pump circuit 10. The hot water can be supplied to the terminal only by the hot water that has passed through the water heat exchanger 11 (instant boiling mode).

  In order to supply hot water to the terminal at the temperature set at this time, the temperature is sensed by the temperature sensor 55, and the hot water that flows out of the water heat exchanger 11 and passes through the mixing valve 61 is mixed with the bypassed water. With the valve 62, the set hot water is supplied to the terminal. In particular, when the temperature of the water supplied from the water supply pipe 16 is high, such as in summer, the temperature of the hot water output from the water heat exchanger 11 becomes higher than the set temperature. At this time, the mixing valve 62 is adjusted so as to reach the set temperature, whereby water is appropriately mixed and hot water is supplied to the terminal (water mixing mode).

  If the refrigerating cycle 10 is controlled by an inverter capable of controlling the number of revolutions of the compressor 1, the temperature of the tap water from the water heat exchanger 11 is sensed by the temperature sensor 53, and the number of revolutions of the compressor 1 is controlled to set the water temperature. Can be

  Further, in the refrigeration cycle 10 itself, the expansion valve 5 is adjusted so that the difference between the temperature sensor 58 disposed in the middle of the evaporator 6 and the compressor suction temperature sensor becomes constant.

  Then, when the use terminal is closed, the flow rate sensor 21 detects this, and when the hot water temperature of the hot water tank 13 is equal to or lower than the set value, the operation shifts to the additional heating operation of the hot water tank 13.

  In the additional cooking operation of the hot water supply tank, the pump 15 is operated while the refrigeration cycle 10 is operated, waiting for the water heat exchanger outlet temperature to reach a high temperature (hot water storage temperature). As a result, the water accumulated in the lower part of the hot water supply tank 13 reaches the water heat exchanger 11 and becomes hot water, and is returned to the upper part of the hot water supply tank 13 via the check valve 49. The check valve 49 serves to prevent hot water from the hot water supply tank 13 when the hot water from the tank is fully closed by the mixing valve 61 during the normal hot water supply.

  The outlet temperature of the water heat exchanger at this time is changed by changing the rotation speed of the compressor 1 and the flow rate of the circulating pump 15. The tank temperature sensor 56 detects the completion of boiling of the hot water tank, and the additional temperature of the hot water tank 13 is detected. The cooking is finished and the apparatus enters a standby state.

  Since hot water is supplied from the hot water supply tank 13 to the terminal by supplying water from the water supply pipe 16, the tank is kept full and the amount of hot water in the hot water supply tank 13 does not decrease in principle. It is necessary to supply water (hot water) at the start of use after draining hot water from the hot water supply tank 13 when the installation is completed or when the hot water supply tank 13 is not used for a long period of time. In this case, when the shower 25 and the faucet 24 of the use terminal 27 are opened, the water from the water supply pipe 16 flows to the use terminal 11 via the water heat exchanger 11. At this time, since the detection value of the tapping temperature sensor 55 detects a low temperature, the mixing valve 62 is only on the hot water side (water from the water supply pipe 16 is not mixed). Further, since the detection value of tapping temperature sensor 54 is also low, mixing valve 61 is opened so that the hot water from water heat exchanger 11 and the water from hot water supply tank 20 are mixed. However, water is not yet output from the hot water supply tank 13 via the mixing valve 61 because the water is not yet filled in the hot water supply tank 13. Since the mixing valve 61 has also opened the hot water supply tank 13 side, the air has come to escape, so that the water from the water supply pipe 16 flows into the water heat exchanger 11 and also into the hot water supply tank 13. Then, when the plug of the use side terminal 27 is stopped when the tank is full, the additional cooking of the hot water supply tank 13 described above is started.

  By the way, even if the compressor 1 of the refrigeration cycle 10 is converted to an inverter, the refrigeration cycle has a minimum capacity and a maximum capacity. The capacity required for hot water supply can be estimated from the feed water temperature sensor 52, the flow sensor 21, and the set hot water temperature.

  If the required hot water supply capacity is equal to or less than the minimum capacity of the refrigeration cycle, the refrigeration cycle 10 is not operated, and the same circuit as in normal hot water supply (hot water (water) from the water heat exchanger 11 and hot water from the hot water tank 13) is used. And an operation circuit for mixing the hot water and the hot water is supplied only at the hot water supply tank 13 at the set temperature. When the amount of remaining hot water in the tank (the temperature of the hot water has dropped) has decreased, the tank is re-cooked and the tank is replenished with hot water.

  Instantaneous water heaters, such as gas water heaters, do not have auxiliary tanks and cannot supply hot water with a capacity lower than the minimum capacity (temperature is adjusted with a mixer tap on the use side terminal). Therefore, even in such a case, hot water can be supplied to the terminal at the set temperature.

  When the hot water supply capacity exceeds the maximum capacity of the refrigeration cycle 10, the flow is adjusted to the set hot water temperature by adjusting the flow rate of the flow control valve 63 to reduce the flow rate.

  Normally, heat pump type water heaters use midnight power, and the water is heated to 70 ° C to 90 ° C in a large tank of 300 liters or more and stored in hot water. According to the present invention, since the hot water is heated at the temperature of the hot water required at the terminal (for example, 42 ° C. which is generally used), the heat efficiency is extremely improved as compared with other heat pump water heaters.

  When hot water is supplied to the bathtub 26, hot water is supplied to the bathtub 26 by performing the same hot water supply operation as described above and opening the pouring solenoid valve 51. If the hot water is not supplied to the bathtub 26, the hot water in the bathtub 26 may flow backward. Therefore, the check valve 50 is used to prevent the hot water from taking into consideration sanitation.

  In addition, since the hot water supply to the bathtub 27 is over 180 liters of hot water, the heat pump circuit 10 is operated without using the hot water in the hot water supply tank 13 in the initial operation, which is different from the case of the above hot water supply operation. Then, the operation of directly pouring water from the water heat exchanger 11 may be performed. This is because 180 liters or more of hot water is required to fill the bathtub 26, and the rise time of the refrigeration cycle 10 is short for the whole. Since the water level in the bathtub 26 is monitored by the water level sensor 60, when the water level reaches the set water level, the operation of pouring the water into the bathtub and the hot water filling operation is stopped.

  Next, additional cooking in the bath will be described. As in the case of the conventional bath kettle, the bathtub 26 is already filled with water, and when trying to boil the water, the electric water heater or the like stored in a large tank cannot boil the water stretched in the bathtub. Was.

  However, in the present embodiment, since the condenser 3 for condensing the refrigerant, the water heat exchanger 11 for boiling hot water and the bathtub water heat exchanger 44 are integrated, the heat pump circuit 10 is used. By operating the circulating pump 46 to circulate the water stretched in the bathtub 26, the water in the bathtub can be boiled. That is, the water stretched in the bathtub 26 is sent to the bathtub water heat exchanger by the circulation pump 46 to be heated, and then returned to the bathtub 26 again. When the detected value of the bath temperature sensor 57, which is provided upstream of the bathtub water heat exchanger 44 and detects the water temperature in the bathtub, reaches a set temperature, the heat pump circuit (mainly the compressor 1) and the circulation pump It has a function to stop the operation of 46. That is, an automatic function for automatically keeping the hot water temperature in the bathtub at a set value is provided.

  As described above, since the bathtub 26 can be poured, filled with hot water, and heated, a variety of bath automatic operations such as adding hot water when the amount of water in the bathtub 26 is low and reheating when the temperature of the hot water becomes low. Has functions.

  FIG. 2 shows a characteristic curve obtained by experimenting the relationship between the time of the transient period at the beginning of operation and the temperature of water.

  It is said that the temperature of hot water and the amount of hot water used at the use terminal 27 in a general household are about 6 to 8 liters / minute at about 40 to 42 ° C. Based on this, the temperature of the supplied water was set to 8 ° C. in the experiment in consideration of the outside air conditions in winter.

  The graph shows the change in the water temperature at the outlet of the water heat exchanger 11 when the water is supplied to the water heat exchanger 11 at the same time when the heat pump circuit 10 is operated. It can be seen that it takes about 7 minutes for 8 ° C. water to be supplied to the inlet of the water heat exchanger 11 and for the hot water temperature at the outlet of the water heat exchanger 11 to reach 42 ° C.

  I can't stand waiting 7 minutes for the hot water to rise in the kitchen faucet 24 or shower 25.

  In the present embodiment, based on this experiment, a small-capacity hot water supply tank 13 of about 30 liters (actually 90 liters with a margin) is provided, and hot water of about 60 ° C. is stored.

  At the terminal in use, tap water from the water heat exchanger 11 of 8 ° C. is added as an initial value to hot water of 60 ° C., and the water is diluted to 42 ° C. for use. For example, the water temperature from the water heat exchanger 11 is Even if the temperature remains unchanged at 8 ° C., about 5 minutes can be compensated if 30 liters of hot water at 60 ° C. is used. In addition, a hot water supply tank of this size can be housed in the heat pump circuit box, so it does not require a large installation space unlike a conventional heat pump water heater and has a small mass, so it is strong. Since it does not require any special ground, it can be installed on the veranda of an apartment or condominium.

  Next, the installation position of the hot water supply tank 13 will be described. The hot water supply tank 13 may be installed at a position below the heat pump circuit 10 as shown in FIG. 3, a structure at the upper portion of the heat pump circuit 10 as shown in FIG. 4, or a structure at the side of the heat pump circuit 10 as shown in FIG. Can be considered.

  When provided at the lower part of the heat pump circuit 10 as shown in FIG. 3, the stability of the heat pump water heater is improved because the hot water supply tank 13 containing hot water is located at the lower part of the box. The workability is good because it can be assembled one after another, and the internal equipment can be easily inspected simply by removing the box 23 in service, so that the serviceability is improved. A control circuit 30 controls the compressor 1, the pressure reducing device 5, the various mixing valves, the fan 9 and the like based on the outputs of various sensors and the like. The same applies to the following figures.

  However, when provided in the lower part of the box, the hot water supply tank 13 storing hot water is close to the ground, so that the amount of heat radiated from the surface of the hot water supply tank 13 increases, and extra energy is wasted. In order to avoid this, it is conceivable to provide the hot water supply tank 13 above the heat pump circuit 10 as shown in FIG. In this case, the heat generated by the heat pump circuit 10 wraps around the hot water supply tank 13, so that excess heat radiation from the hot water supply tank 13 can be reduced.

  Further, as shown in FIG. 5, it is also possible to suppress unnecessary heat radiation from the hot water supply tank 13 while installing the heat pump circuit 10 beside the heat pump circuit 10 and ensuring the assembling property and the serviceability.

  Alternatively, as shown in FIG. 6, it is conceivable to stop storing the heat pump circuit 10 integrally and install the hot water supply tank 13 beside the box in which the heat pump circuit 10 is placed. In this case, the heat pump circuit 10 relating to the refrigerant and the water circulating portion relating to the hot water supply are separated, and products can be produced in parallel with each other, so that the productivity of the products is improved, and the installation can be performed separately. Installation work becomes easy, and in service, workability of service can be further improved.

It is a figure showing an example of a heat pump circuit and a water circuit of a heat pump water heater of the present invention. 6 is a characteristic curve of water temperature and time after the heat pump circuit operation starts. It is a block diagram which incorporated the hot water supply tank in the lower part of the heat pump circuit. It is a block diagram which incorporated the hot water supply tank in the upper part of the heat pump circuit. It is a block diagram which incorporated the hot water supply tank beside the heat pump circuit. It is a block diagram in which the hot water supply tank was provided outside the heat pump circuit main body.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Heat exchanger, 3 ... Condenser, 5 ... Decompression device, 6 ... Evaporator (outdoor heat exchanger), 7 ... Accumulator, 8 ... Bypass valve, 9 ... Blower, 10 ... Heat pump circuit, DESCRIPTION OF SYMBOLS 11 ... Water heat exchanger, 13 ... Hot water supply tank, 15 ... Circulation pump, 16 ... Water supply pipe, 17 ... Pressure reducing valve, 19 ... Water supply pipe, 20 ... Hot water supply pipe, 21 ... Flow meter, 22 ... Water circulation circuit 23 ... Outer box , 24 ... faucet, 25 ... shower, 26 ... bathtub, 27 ... use terminal, 30 ... control circuit, 53 ... water heat exchanger outlet temperature sensor, 56 ... hot water tank temperature sensor, 61, 62 ... mixing valve, 63 ... flow rate Regulating valve.

Claims (2)

A compressor, a first heat exchanger that exchanges heat between the refrigerant discharged from the compressor and water introduced from a water pipe connected to a water supply pipe, and decompresses the refrigerant from the first heat exchanger. A pressure reducing device, a heat pump circuit having a second heat exchanger provided between the pressure reducing device and the compressor,
A hot water supply tank for storing hot water heated by the first heat exchanger, and a mixing for mixing hot water introduced from the water pipe and heated via the first heat exchanger with hot water stored in the hot water tank; Means for supplying hot water to the bath tub by operating the heat pump circuit without using hot water in the hot water supply tank when pouring hot water into the bath tub, and pouring hot water from the first heat exchanger into the bath tub. Machine. 2. The method according to claim 1, wherein the hot water from the first heat exchanger is poured into the bath tub without using hot water from the hot water supply tank even when the hot water is poured into the bath tub at an early stage of the operation of the heat pump circuit. Heat pump water heater.

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