JP4262657B2 - Heat pump water heater - Google Patents

Description

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

  Conventional water heaters do not have hot water storage tanks, but have a combustion water heater that burns gas, etc., instantaneously boiles water with its powerful combustion heat, and supplies hot water, and a large capacity hot water storage tank. There were electric water heaters that used a cheap nighttime power at night to store a large amount of hot water heated by an electric heater during the night in a hot water tank and use the hot water stored in the hot water tank during the day.

  However, recently, heat pump water heaters that are said to have an energy efficiency of 300 to 500% better than electric water heaters have begun to spread. The heat pump water heater uses the state change of the refrigerant as a heat source, so it is said to be environmentally friendly water heater that is several times more energy efficient than electric heater heating and that does not burn gas etc. and therefore does not emit CO2. . However, since there is no strong amount of heat as when gas is burned, a large-capacity hot water tank is provided like an electric water heater, and hot water is boiled in the heat pump circuit at night using cheap electricity. 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 tank for storing a large amount of hot water boiled in the heat pump circuit are provided as separate devices, 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 Laid-Open No. 9-126547 is known. A heat pump circuit composed of a compressor, a condenser, a decompression device, and an evaporator, and a large-capacity hot water storage tank, and water from a lower part of the hot water tank to a water heat exchanger that becomes a condenser of the heat pump circuit via a circulation pump Piping is connected, and a boiling water circuit is provided by connecting hot water piping to the outlet of the water heat exchanger and the upper part of the hot water tank.

  Then, an energy efficient heat pump circuit is operated using cheap electric power at night, and the water in the hot water tank is gradually warmed up to a predetermined hot water temperature with a hydrothermal exchanger while circulating the water in the circulation pump. The temperature of the hot water is detected by a temperature detector and the operation of the heat pump circuit is stopped.

  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 suitable temperature by mixing with a mixing valve.

  In addition, when the hot water temperature of the hot water tank decreases, there is no detailed description about the hot water supply route, but it is described that the hot water in the hot water tank is reheated with a water heat exchanger and a heater and supplied to the terminal for use. Yes.

JP-A-9-126547

  However, considering that the hot water stored in the hot water tank is filled with hot water in the bathtub, the capacity of the hot water tank is close to 200L as in the bathtub, and 500L is necessary if there is some margin for the use of other hot water. There is also. When hot water is stored to the full capacity of the hot water storage tank, its mass exceeds 200 kg to 500 kg. Therefore, heat pump water heaters could not be installed unless the foundation work was done to make the ground solid, and the installation space was large enough.

  Furthermore, in order to boil a large amount of hot water, a large amount of energy is required, and storing it as high-temperature hot water increases the difference from the outside air temperature and increases heat loss due to heat dissipation. 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.

  Also, conventional heat pump water heaters use cheap electricity charges at night, operate the heat pump circuit at night to store hot water in the hot water tank, and store it in the hot water tank without operating the heat pump circuit during the day. Since the basic usage is to use hot water, the hot water in the hot water tank is sometimes used up, and the water cannot be immediately heated up, resulting in running out of hot water. In the heat pump water heater described in the above-mentioned Japanese Patent Application Laid-Open No. 9-126547, hot water is stored using electric power at night as in an electric water heater, and additional cooking operation is performed when hot water is insufficient. It is auxiliary.

  Also, in order to store a large amount of hot water at a temperature higher than the outside air temperature, heat is radiated from the surface of the hot water tank, resulting in wasted energy, and warming it up in the evening as the temperature drops. There was a need.

  An object of the present invention is to provide an energy efficient heat pump water heater with a small space and mass required for installation.

The object is to provide a first heat exchanger for exchanging heat between the compressor, the refrigerant discharged from the compressor and the water introduced from the water supply pipe, and a decompression device for decompressing the refrigerant from the first heat exchanger. A heat pump circuit having a second heat exchanger provided between the decompressor and the compressor;
After the rise of the heat pump circuit, the water introduced from the water supply pipe is heated by the first heat exchanger, and the instantaneous direct hot water supply circuit that can supply hot water to the use terminal;
While the instantaneous direct hot water supply circuit starts up, a hot water supply tank that assists hot water supply to the use terminal ,
Mixing means for mixing hot water heated from the water supply pipe through the first heat exchanger and hot water stored in the hot water tank,
The refrigerant is carbon dioxide, and the hot water storage capacity of the hot water tank is less than the hot water storage capacity of the CFC-based chlorofluorocarbon refrigerant to 100 liters or less, so that the heat pump circuit and the hot water tank can be stored in a box. The hot water tank is achieved by being installed beside the heat pump circuit in the box.

Also achieved by a pre-Symbol heat pump water heater with a hot water storage capacity of the water heater tank less than 60 liters.

  According to the present invention, it is possible to provide an energy efficient heat pump water heater with a small space and mass required for installation.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the heat pump water heater of the present invention.

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

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

  8 and 8a are bypass valves. By opening the bypass valve, high-temperature and high-pressure refrigerant discharged from the compressor 1a is passed through the evaporators 6 and 6a, so that frost attached to the evaporators 6 and 6a. Is melted (defrost control). The timing of this defrosting control may be simultaneous with two refrigerant circuits, or may be shifted. When shifted, there is an effect that hot water can be supplied without interruption, although the performance is somewhat reduced.

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

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

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

  The heat pump water heater according to the present embodiment is a small and light water heater without using a large hot water tank as in the prior art. That is, in a water heater that boils hot water by exchanging heat between the high-temperature refrigerant in the heat pump circuit 10 and the water in the water circulation circuit 22 in the water heat exchanger 11, the water introduced from the water supply pipe 16 is removed by the water heat exchanger 11. By adopting an instantaneous system in which the temperature is raised and the hot water is supplied to the use terminal 27 as it is, a conventional large hot water storage tank can be dispensed with. Further, since the heat of condensation sufficient to warm the water cannot be generated until the pressure condition immediately after the start of the operation of the heat pump circuit 10 is stabilized, the hot water stored in the hot water supply tank 13 can be used for a short period of time. By mixing the water from the water heat exchanger 11 and supplying hot water, the hot water tank 13 can be reduced in size while maintaining the set temperature. When the operation of the heat pump circuit 10 was stabilized and the hot water at the set temperature was boiled up, the hot water stored in the hot water supply tank 13 was stopped and the hot water was supplied directly. This will be described in detail below.

  The supply of water to the heat pump water heater will be described. Water supplied from the water supply pipe 16 flows into the pressure reducing check valve 17. One end of the water is connected to the hot water tank 13 through the water supply pipe 19 and the other is connected to the water heat exchanger 11. To the heat exchanger 2. The hot water supply to the use terminal 27 is supplied to the set temperature through the mixing valves 61 and 62 and the flow rate adjusting 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 hot water to the use terminal 27. Yes. For this reason, if the capacity of the refrigeration cycle is high or 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 can be dramatically more compact than a conventional electric water heater that has taken 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 warmed.

  Therefore, in this embodiment, the minimum necessary hot water supply tank 13 is installed, and 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. Thus, the hot water supply temperature at the use terminal 27 is secured.

  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 having a predetermined high temperature is stored in the hot water supply tank 13 to ensure hot water supply at a set temperature when the next hot water is used. Can do. The operation of each part will become gradually clear from the following description.

  As described above, the mixing valve 61 assists the hot water in the hot water supply tank 13 when the temperature of the hot water coming out of the heat exchanger 2 (water heat exchanger 11) does not rise sufficiently immediately after the start of the heat pump circuit operation. This 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.

  Further, 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 when the temperature of the hot water supplied from the mixing valve 61 is higher than the set temperature. is doing.

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

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

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

  As the use terminal 27, a faucet 24 such as a kitchen, a bathroom shower 25, a bathtub 26 divided by a pouring electromagnetic valve 51 and a check valve 50, and the like are provided. This check valve 50 is a valve for preventing hot water in the bathtub 26 from being mixed with hot water supplied from the water supply pipe 16 in terms of hygiene. Although not specifically described in the present embodiment, water terminals are attached to the respective terminals as necessary.

  The heat pump water heater according to the present embodiment has such a configuration and performs an operation as described below. A heat pump water heater is said to be 300-500% better in energy efficiency than an electric water heater. The heat pump circuit 10 is used to supply hot water directly to the terminal in use like an instantaneous water heater. However, as described above, the heat pump circuit 10 can sufficiently supply the condensation heat necessary for warming the water in the water heat exchanger 11 immediately after the start of operation until the heat pump circuit is stabilized. Therefore, the hot water cannot be directly supplied to the use terminal 27. In the heat pump water heater of the present embodiment, the hot water stored in the small-capacity hot water supply tank 13 is supplementally supplied for use for several minutes.

  First, the capacity of the hot water supply tank 13 will be described. Except in extreme cases, the amount of shower water in a general household is 11.8 liters / minute, the kitchen is 8.5 liters / minute, the washroom is 7.5 liters / minute, and the continuous use time However, the shower is 9.7 minutes and the kitchen is 13.4 minutes. If the simultaneous use is not taken into consideration, the necessary continuous hot water supply is about 114 liters. The hot water supply temperature is 40 ° C., the hot water temperature stored in the hot water supply tank 13 is 60 ° C., which is said to be the temperature at which Salmorena bacteria die, etc., and the temperature of the water supplied from the heat exchanger 2 is considered in the worst state Assuming 8 ° C. Under this condition, the amount of hot water that must be stored in the hot water supply tank 13 is about 70 liters. However, since the temperature of the water supplied from the heat exchanger 2 cannot always be considered to be 8 ° C., the capacity of the hot water supply tank 13 is 60 liters if the temperature is about 18 ° C., which is 10 ° C. higher than this.

  Further, if the size of the outdoor unit of the packaged air conditioner currently on the market is an allowable size for a domestic water heater, the height is about 1.4 m, the width is 0.9 m, and the depth is about 0.3 m. When the hot water tank 13 is stored in the box of the outdoor unit, the maximum allowable size is 0.3 m for the hot water tank 13 and 1.4 m for the height. 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 the range of 60 liters to 100 liters. If the hot water storage capacity of the hot water supply tank 13 falls within this range, the outdoor unit can be stored in a single box, such as a packaged air conditioner or room air conditioner, as long as it does not interfere with the use of hot water as described above. Can do. 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 decompression device 5 as main components.

  By the way, in a refrigeration cycle using a CFC-based chlorofluorocarbon refrigerant, 60 ° C. is the temperature at which the boiling is almost maximized, but if carbon dioxide (CO 2) is used as the refrigerant, the hot water temperature can be further increased. The hot water storage capacity of the hot water supply tank 13 may be reduced by the amount increased.

  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 operation, the heat pump circuit 10 is still in a standing state, so that the hot water supply operation using the hot water supply tank 10 is performed. The water introduced 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 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 water circuits that flow to the water heat exchanger 11 in order to heat the water by the refrigeration cycle 10. The temperature is sensed by the temperature sensor 54 so that the temperature is set by the mixing valve 61 that mixes the hot water from the hot water supply tank 13 and the hot water from the water heat exchanger 11, the hot water from the hot water storage tank 13, and the refrigeration cycle 10. It adjusts with the quantity of the water from the water heat exchanger 11 heated more. In the initial stage of operation, the water passing through the water heat exchanger 11 is not sufficiently warmed, so the amount of hot water from the hot water supply tank 13 is large, and the amount of water flowing through the water heat exchanger 11 is small ( Mixed operation mode). Here, in the initial stage of operation, when the amount of water flowing through the water heat exchanger 11 is reduced, the temperature can be rapidly increased due to a small amount of water.

  In this mixing operation mode, when the temperature of the hot water of the use terminal 27 is too high (when it 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.

  As the operation continues, the heat pump circuit 10 begins to stabilize gradually, the temperature of the hot water discharged from the water heat exchanger 11 also becomes high, and a mixing valve that mixes the hot water from the hot water supply tank 13 and the hot water from the water heat exchanger 11. 61 gradually squeezes 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, the hot water from the hot water supply tank 13 is fully closed and heated by the heat pump circuit 10. The hot water can be supplied to the terminal using only the hot water that has passed through the water heat exchanger 11 (instantaneous water heating mode).

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

  If the refrigeration cycle 10 is an inverter control that can control the rotation speed of the compressor 1, the temperature sensor 53 senses the tapping temperature of the water heat exchanger 11, and controls the rotation speed of the compressor 1 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 is constant.

  When the use terminal is closed, the flow rate sensor 21 senses this, and when the hot water temperature of the hot water supply tank 13 is equal to or lower than the set value, the hot water supply tank 13 is shifted to the additional cooking operation.

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

  Further, the outlet temperature of the water heat exchanger at this time is changed by changing the number of revolutions of the compressor 1 and the flow rate of the circulation pump 15, the completion of boiling of the hot water tank is detected by the tank temperature sensor 56, and the additional temperature of the hot water tank 13 is increased. Finish cooking and enter standby.

  In addition, since the hot water supply from the hot water supply tank 13 to the terminal is performed by supplying water from the water supply pipe 16, a full tank state is maintained and the amount of hot water in the hot water supply tank 13 is not reduced in principle. When the installation is completed or when the hot water tank 13 is not used for a long period of time, the hot water tank 13 is drained, and there is no hot water in the hot water tank 13 at the start of use. In this case, when the shower 25 and the faucet 24 of the use terminal 27 are opened, 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 hot water 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 the hot water temperature sensor 54 is also low, the mixing valve 61 is opened so that the hot water from the water heat exchanger 11 and the water from the hot water supply tank 20 are mixed. However, since water is not yet filled in the hot water supply tank 13, the water is not output from the hot water supply tank 13 through the mixing valve 61. Then, since the mixing valve 61 is also opened on the hot water supply tank 13 side, air can be removed, so that water from the water supply pipe 16 flows into the water heat exchanger 11 and also into the hot water supply tank 13. And if the stopper 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 into an inverter, the refrigeration cycle has a minimum capacity and a maximum capacity. The capacity required for hot water supply can be estimated by the water supply temperature sensor 52, the flow rate sensor 21, and the set hot water temperature.

  If the required hot water supply capacity is less than or equal to the minimum capacity of the refrigeration cycle, the refrigeration cycle 10 is not operated, and the same circuit (hot water (water) from the water heat exchanger 11 and hot water from the hot water tank 13) as in normal hot water supply. And the hot water supply tank 13 alone is used to discharge hot water at a set temperature. When the amount of remaining hot water in the tank (the temperature of the hot water has decreased) is reduced, the tank is additionally cooked to supply hot water to the tank.

  Instantaneous water heaters such as gas water heaters do not have auxiliary tanks, and therefore cannot supply hot water below the minimum capacity (the temperature is adjusted with a mixing plug on the use side terminal), but in this embodiment, hot water tank 13 Even in such a case, the terminal can be supplied with hot water at a set temperature.

  When the hot water supply capacity exceeds the maximum capacity of the refrigeration cycle 10, the flow rate adjustment valve 63 is adjusted to adjust the flow rate so that the hot water is discharged at the set hot water temperature.

  Usually, heat pump type hot water heaters use midnight electric power and boil and store hot water in a large tank of 300 liters or more at 70 ° C to 90 ° C. According to the present invention, since the hot water is boiled at the temperature of hot water required at the terminal (for example, 42 ° C., which is generally used), the thermal efficiency is very good compared to other heat pump type hot water heaters.

  When hot water or hot water is filled in the bathtub 26, the hot water supply operation is performed in the same manner as described above, and hot water is filled in the bathtub 26 by opening the hot water solenoid valve 51. Moreover, since it is possible that the hot water of the bathtub 26 flows backward when the pouring of the hot water into the bathtub 26 is interrupted, this is prevented by the check valve 50 in consideration of hygiene.

  Moreover, since the hot water filling of 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, unlike the above hot water supply operation. And it is good also as a driving | running which pours the water of the direct water heat exchanger 11. 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 very small relative to the whole. Since the water level of the bathtub 26 is monitored by the water level sensor 60, the hot water filling operation and the hot water filling operation are stopped when the set water level is reached.

  Next, additional cooking of the bath will be described. Like the conventional bath, water is already in the bathtub 26, and if you try to boil it, you cannot boil the water in the bathtub with an electric water heater or the like stored in a large tank. It was.

  However, in the present embodiment, the heat pump circuit 10 is provided because the condenser 3 that condenses the refrigerant, the water heat exchanger 11 that boils hot water and the bathtub water heat exchanger 44 are integrated into the heat exchanger 2. By operating, circulating pump 46 is operated and the water stretched in bathtub 26 is circulated, 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, heated, and returned to the bathtub 26 again. And when the detection value of the bath temperature sensor 57 which is provided in the upstream of the bathtub water heat exchanger 44 and detects the water temperature in the bathtub reaches the set temperature, the heat pump circuit (mainly the compressor 1) and the circulation pump 46 has a function to stop the operation. That is, an automatic function for automatically maintaining the hot water temperature in the bathtub at a set value is provided.

  As described above, the bath 26 can be poured, filled with hot water, and can be reheated. Therefore, various bath automatics such as adding hot water when the hot water in the bathtub 26 is low and reheating when the hot water becomes cold are available. It has a function.

  Further, FIG. 2 shows a characteristic curve obtained by experimenting the relationship between the time of the transition period in the initial operation and the temperature of the 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 is set to 8 ° C. in the experiment in consideration of the outdoor air condition in winter.

  The graph represents a change in the water temperature at the outlet of the water heat exchanger 11 when water is supplied to the water heat exchanger 11 simultaneously with the operation of the heat pump circuit 10. 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 until the hot water temperature at the outlet of the water heat exchanger 11 reaches 42 ° C.

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

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

  At the terminal used, tap water from the 8 ° C. water heat exchanger 11 is added to 60 ° C. hot water and diluted to 42 ° C., so that the water temperature from the water heat exchanger 11 is Even if the temperature remains unchanged at 8 ° C., 30 liters of hot water at 60 ° C. can compensate for about 5 minutes. In addition, a hot water tank of this size can be housed integrally in the heat pump circuit box, so that it does not require a large installation space as in the case of a conventional heat pump water heater, and the mass is small and strong. Since it does not require a solid ground, it can be installed on the verandas of apartments and condominiums.

  Next, the installation position of the hot water tank 13 will be described. As shown in FIG. 3, the hot water supply tank 13 is installed at the lower part of the heat pump circuit 10, as shown in FIG. 4, at the upper part of the heat pump circuit 10, or at the side of the heat pump circuit 10 as shown in FIG. Can be considered.

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

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

  In addition, as shown in FIG. 5, it is possible to suppress the wasteful heat radiation from the hot water supply tank 13 while being installed beside the heat pump circuit 10 and ensuring assembling and serviceability.

  Alternatively, as shown in FIG. 6, it is also conceivable to stop the housing from being integrated into the box and to install the hot water supply tank 13 on the side of the box containing the heat pump circuit 10. In this case, the heat pump circuit 10 related to the refrigerant and the water-circulating portion related to the hot water supply are separated, and products can be produced in parallel with each other, so that the productivity of the product is improved and the work can be performed separately even during installation. Installation work is facilitated, and service operability can be further improved.

It is a figure which shows one Example of the heat pump circuit and water circuit of the heat pump water heater of this invention. It is a characteristic curve of the temperature and time of water after heat pump circuit operation start. It is the block diagram which incorporated the hot water supply tank in the lower part of the heat pump circuit. It is the block diagram which incorporated the hot water supply tank in the upper part of the heat pump circuit. It is the block diagram which incorporated the hot water supply tank beside the heat pump circuit. It is the block diagram which provided the hot water supply tank outside the heat pump circuit main body.

Explanation of symbols

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 ... Terminal used, 30 ... Control circuit, 53 ... Water heat exchanger outlet temperature sensor, 56 ... Hot water tank temperature sensor, 61, 62 ... Mixing valve, 63 ... Flow rate tuning valve.

Claims (2)

A compressor, a first heat exchanger that exchanges heat between the refrigerant discharged from the compressor and water introduced from the water supply pipe, a decompression device that decompresses the refrigerant from the first heat exchanger, and the decompression device And a heat pump circuit having a second heat exchanger provided between the compressors,
After the rise of the heat pump circuit, the water introduced from the water supply pipe is heated by the first heat exchanger, and the instantaneous direct hot water supply circuit that can supply hot water to the use terminal;
While the instantaneous direct hot water supply circuit starts up, a hot water supply tank that assists hot water supply to the use terminal ,
Mixing means for mixing hot water heated from the water supply pipe via the first heat exchanger and hot water stored in the hot water tank,
The refrigerant is carbon dioxide, and the hot water storage capacity of the hot water tank is less than the hot water storage capacity of the CFC-based chlorofluorocarbon refrigerant to 100 liters or less, so that the heat pump circuit and the hot water tank can be stored in a box. The heat pump water heater is characterized in that the hot water tank is installed beside the heat pump circuit in the box.   The heat pump water heater according to claim 1, wherein the hot water storage capacity of the hot water tank is less than 60 liters.

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