JP2015227766A - Heat pump water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which, a heat pump water heater is a machine for storing hot water in a hot water storage unit during night time and for supplying the hot water, and it performs a boiling operation of hot water mainly by utilizing midnight power, and even when an operation sound of the heat pump unit is comparatively quiet, depending on an installation environment, the operation sound is regarded as noise, and it becomes a problem.SOLUTION: In order to solve the problem, a heat pump water heater includes: a heat pump unit including a plurality of refrigeration cycles; and a hot water storage unit for storing hot water boiled by using the heat pump unit. In the heat pump water heater, a boiling operation by the heat pump unit includes: a normal operation mode for performing boiling by using all the refrigeration cycles; and a saving operation mode for performing boiling by using one part of the refrigeration cycles.

Description

  The present invention relates to operation control of a heat pump water heater, and more particularly to operation control of a heat pump unit.

  In general, heat pump water heaters operate the heat pump unit using discounted electricity charges at night, heat the water and store it in a hot water storage tank as high temperature water, and use hot water with a faucet open during the day Sometimes hot water in the hot water storage tank is mixed with water to supply hot water as appropriate temperature water.

  In the heat pump water heater, the heating capacity (output) of the heat pump unit is also set according to the tank capacity of the hot water storage unit. This combination is capable of heating up the full capacity of the combined hot water storage tanks in the nighttime when midnight power is available (generally 10 hours from 22:00 midnight to 8:00 in the morning). Is set. In particular, a set heating capacity is required in winter conditions where the outside air temperature is low and the water temperature decreases. On the other hand, since the incoming water temperature is high in the summer and intermediate periods (spring and autumn), a predetermined heating capacity is not necessarily required. In summer and the like, an operation with a reduced heating capacity may be performed.

  Since the hot water storage type heat pump water heater performs the boiling operation mainly in the middle of the night time in this way, the operation sound may become a problem. The operating sound of the heat pump water heater varies depending on the heating capacity and season, and when the heating capacity is large (when the output is large), or in winter conditions when the outside air temperature and water temperature decrease, the rotational speed of the compressor and the fan The rotational speed increases (increases speed), and generally the driving sound increases. For this reason, depending on the surrounding environment (noise situation), it may be regarded as a problem as noise. Under noisy conditions, such as in a late-night residential area, the driving sound may be noisy even under the conditions of high ambient noise, such as during the daytime, in downtown and industrial areas.

  The heating capacity of the heat pump unit is set so that the tank capacity of the combined hot water storage unit can be heated, but actually the required heating capacity varies depending on the amount of hot water used and the water temperature at the time of boiling. However, it is often possible to boil below the heating capacity that is normally set. Moreover, it is not limited to midnight power, and when the amount of hot water is insufficient, it may be operated to boil in the morning or evening, and from the above, it is not always necessary to always operate with the set heating capacity. .

  In general, when the operation is performed with the heating capacity reduced, the cycle efficiency is improved and the coefficient of performance (COP) of the refrigeration cycle is improved. For this reason, it is possible to operate efficiently by performing an operation in which the heating capacity is reduced rather than an operation with a predetermined heating capacity, and it becomes possible to further save energy, reduce the utility cost, and reduce the operation sound. On the other hand, the hot water storage type heat pump water heater uses hot water stored in the hot water storage tank to supply hot water, so if you use a lot of hot water and the hot water in the hot water storage tank decreases, the hot water cannot be used. The problem of “out” occurs. For this reason, in order to prevent running out of hot water, the amount of remaining hot water in the hot water storage tank is monitored, and control such as appropriately heating the heat pump unit is performed. Unlike gas water heaters, heat pump units make hot water over time, so if hot water runs out, hot water cannot be used immediately for hot water supply even if the heat pump unit is heated. For this reason, in the hot water storage type, it is important to prevent hot water from running out and to save energy and reduce noise.

  In view of these, Patent Document 1 includes a means for detecting the amount of remaining hot water in the hot water storage tank, changes the heating capacity of the boiling according to the outside air temperature and the remaining hot water amount of the hot water storage tank during the heating operation in the night time zone, and the daytime. In the boiling period, the operation is performed with the heating capacity maximized, and in the late-night boiling operation, the operation noise of the heat pump unit is reduced and the hot water is prevented from running out during the daytime.

JP 2009-287794 A

  In Patent Document 1, by reducing the late-night heating capacity in accordance with the amount of remaining hot water, it is possible to reduce the operation noise at night, and some effects can be expected to suppress the occurrence of noise problems. The invention focuses on the heating operation in consideration, and the driving sound can only be expected to have a secondary effect.

  In order to solve this problem, it is necessary to operate properly according to the environmental conditions in the installed environment. However, if it is equivalent to the ambient noise, there is a need for a driving method that focuses on driving sound such as normal driving. In order to solve this problem, an object of the present invention is to suppress a noise problem by performing a heating operation of a heat pump unit in accordance with ambient environmental conditions.

  In order to solve this problem, the present invention provides a heat pump water heater comprising a heat pump unit having a plurality of refrigeration cycles and a hot water storage unit for storing hot water boiled using the heat pump unit. Boiling operation in the unit is a heat pump hot water supply having a normal operation mode in which boiling is performed using all refrigeration cycles and a save operation mode in which boiling is performed using some refrigeration cycles. Use the machine.

  According to the present invention, in an environment where the surrounding noise is quiet, by selecting the save operation mode, it is possible to reduce the operation sound of the heat pump unit and avoid the occurrence of the noise problem.

The schematic diagram which shows an example of the heat pump refrigerant circuit, the hot water storage circuit, the hot water supply circuit, the operation control means, and components in the heat pump water heater of one Example. The schematic diagram of an example of the boiling operation of the heat pump water heater of one Example. The schematic diagram of an example of operation of the remote control of one Example.

  First, the outline of the present invention will be briefly described. The gist of the present invention is that a heat pump water heater comprising a hot water storage unit and a heat pump unit is provided with an operation mode (save mode) for reducing operation noise during the heating operation of the heat pump unit, and switching between the normal operation mode and the save operation mode. It has functions that can be selected and implemented by the user.

  Usually, operation is performed with a heating capacity generally called a rating. On the other hand, a save mode is provided in advance as an operation mode. Most of the operation sound of the heat pump unit is generated by a compressor and a blower (propeller fan).

  Therefore, the operation with reduced operation noise, that is, the save operation mode is to reduce the number of refrigeration cycles to be operated among a plurality of refrigeration cycles, and these operations simultaneously reduce the heating capacity. It can also be said that the save operation mode is similar to the low heating capacity operation mode.

  The operation mode can be set by the user by operating a user interface such as a remote controller. Whether the operating sound of a heat pump water heater becomes a problem depends largely on the environment in which it is installed. That is, if it is installed in a quiet environment, a small sound at midnight may be regarded as a problem.

  The first invention is provided with such an operation mode, and when installed in a quiet environment, the user can select the save operation mode and maintain the quiet environment. This switching of operation may be performed by the user based on his / her own judgment, or may be set based on opinions regarding noise from the surroundings. For example, this setting is easy to use if the operation is always in the silent operation mode, or only the operation at midnight is in the silent operation mode. Further, a function of automatically switching these determinations from various conditions may be provided.

  Next, the configuration and operation of the heat pump water heater that is Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of the configuration of a heat pump water heater. The heat pump water heater is composed of a heat pump unit 30 that houses components of a plurality of systems of heat pump refrigerant circuits (here, two systems as an example), and a hot water storage unit 40 that houses hot water tanks and hot water circuit components. Communicate with each other and monitor each other's situation, and includes a remote control 50 as an interface to the user.

The heat pump refrigerant circuit is configured by connecting the compressors 1a and 1b, the water refrigerant heat exchanger 2, the decompression devices 4a and 4b, and the air heat exchangers 5a and 5b in series through refrigerant pipes, respectively. Carbon dioxide (CO ₂ ) refrigerant is sealed inside.

  The compressors 1a and 1b can perform rotation speed control from low speed (for example, 700 rotations / minute) to high speed (for example, 6000 rotations / minute) by PWM control, voltage control (for example, PAM control) and combination control thereof. Yes. Since the heating capacity that is the output of the heat pump unit 30 is basically constant, the compressor operates at a low speed in summer when the outside air temperature is high, and operates at a high speed in winter when the outside air temperature is low. The number of rotations is controlled according to the temperature of incoming water and the temperature of outgoing water.

  The water-refrigerant heat exchanger 2 circulates refrigerant-side heat transfer tubes that flow high-temperature refrigerant discharged from the compressors 1a and 1b and low-temperature water below the tank 10 and heats the water-refrigerant heat exchanger 2 with heat. It is comprised with a side heat exchanger tube, heat exchange is performed between a refrigerant | coolant side heat exchanger tube and a water side heat exchanger tube, the heat | fever of the refrigerant | coolant which flows into a refrigerant | coolant tube is transmitted to water, and the temperature of water is raised.

  The low-temperature water in the tank 10 flows from the bottom of the tank 10 into the water-side heat transfer pipe of the water-refrigerant heat exchanger 2 by the circulation pump 15 and is gradually heated by the refrigerant-side heat transfer pipe to be heated to a specified temperature. Hot water is stored from.

  Next, an electric expansion valve is generally used as the decompression device 4a, 4b, and the medium temperature high pressure refrigerant sent through the water refrigerant heat exchanger 2 is decompressed, and the air heat exchanger 5a, 5b as a low pressure refrigerant that easily evaporates. Send to. Further, the decompression devices 4a and 4b function to adjust the refrigerant circulation amount in the heat pump refrigerant circuit by changing the throttle amount of the refrigerant circuit, or when the air heat exchangers 5a and 5b are frosted by operating the heat pump at low temperatures in winter, In some cases, the throttle amount is fully opened and a medium temperature refrigerant is sent to the air heat exchangers 5a and 5b in a large amount to melt the frost.

  The air heat exchangers 5a and 5b take in outside air by the rotation of the blowers 6a and 6b, exchange heat between the air and the refrigerant, and absorb heat from the outside air.

  The hot water storage unit 40 includes a water circulation circuit for performing hot water storage, hot water supply, and the like.

  The hot water storage circuit is a water circuit for storing high-temperature water in the tank 10 mainly by hot water storage operation that is performed regularly at night and when the remaining hot water amount is less than a specified value, and the tank 10 is circulated. A pump 15, a water refrigerant heat exchanger 2, and a tank 10 are sequentially connected in series via a water pipe.

  The hot water supply circuit is configured by sequentially connecting a water supply fitting 7, a pressure reducing valve 8, a water supply amount sensor 9, a tank 10, a hot water mixing valve 12, and a hot water supply fitting 13 in series via a water pipe. In some cases, the water amount sensor can be controlled without being provided, and a direct hot water supply type water heater that directly heats and supplies hot tap water may not have the pressure reducing valve 8.

  The water supply fitting 7 is mainly connected to a water supply source such as water supply, and the hot water supply fitting 13 is connected to a hot water supply load such as a faucet 14. Some water heaters are provided with a hot water filling circuit or a reheating circuit (both not shown).

  Next, the operation control means 52 of the heat pump unit performs operation / stop of the heat pump refrigerant circuit and rotation speed control of the compressors 1a, 1b, and also mainly operates the refrigeration cycle such as adjusting the refrigerant throttle amount of the decompression devices 4a, 4b. The hot water storage unit operation control means 51 controls the hot water mixing valve, which is temperature adjustment for hot water supply, etc., detects the amount of hot water remaining in the hot water tank, and controls the boiling timing and the boiling temperature of the hot water tank. The operation control means 51 and 52 cooperate to control the water heater. As a user interface, a remote controller 50 is provided so that a hot water supply temperature can be set and an error display operation mode can be changed. The circulation pump 15 may be provided in the heat pump unit or the hot water storage unit, and circulates the water at the lower part of the tank so as to boil at a specified temperature. The tank 10 is provided with a plurality of temperature sensors 10a, 10b, 10c, and 10d for detecting the hot water storage temperature and the amount of hot water storage, or by determining the hot water supply load by the flow rate sensor 9 for detecting the hot water use amount to save energy. In many cases, a learning control function for controlling a boiling temperature, a boiling amount, and a boiling time is provided so as to achieve an optimum operation.

  Further, the operation control means 52 of the heat pump unit stores hot water at a specified temperature (for example, 90 ° C.) of high-temperature hot water at low temperatures in winter, and at a high rotation speed (for example, 3000 to 4000) when the ambient temperature or water supply temperature is low and the heating load is large. Rotation / minute), and in the summer and intermediate periods, when the heating load is light, the optimum operation control means such as setting the normal temperature of the hot water (about 65 ° C) to a relatively low number of revolutions (eg 1000 to 2000 rotations / minute). And a pressure sensor (not shown) for detecting the discharge pressure of the compressor 1a1b, discharge temperature sensors 22a and 22b, etc., and an outside air temperature sensor 23 for detecting the outside air temperature and a tapping temperature are detected. There are provided sensors such as a tapping water temperature sensor 20 and a water temperature sensor 21 for detecting the water temperature, and each detection signal is input to the operation control means 52. .

  Next, an example of the operation of the heat pump water heater of this embodiment will be described based on the flowchart of FIG. 2 with reference to the heat pump refrigerant circuit, hot water storage circuit, and hot water supply circuit of FIG.

  FIG. 2 is a flowchart showing an example of a day operation operation in which the boiling operation is performed.

  When the time set by the remote controller (for example, start time 22:00, end time 8:00) is reached, the boiling operation is started (step 61). That is, the compressors 1a and 1b in FIG. 1 are started to start the heat pump operation and the circulation pump 15 is operated, and the tank hot water circulated from the bottom of the tank 10 is heat-exchanged with the high-temperature refrigerant in the water refrigerant heat exchanger 2. Then, hot water storage operation is performed in which high temperature water of a specified temperature is returned and returned from the upper part of the tank 10.

  In the hot water storage amount determination (step 62), the hot water storage operation is continued until the hot water storage temperature and the hot water storage amount reach the specified values. When the hot water storage temperature and the hot water storage amount reach the specified values, the heat pump operation is stopped and the hot water storage operation ends (step 63).

  In the morning, for example, when the faucet 14 is opened and the use of hot water is started (step 64), the operation control means 51 starts from the hot water mixing valve 12 so that the hot water supply temperature becomes an appropriate temperature (generally about 42 ° C.). The hot water supply operation to supply the appropriate temperature water in the hot water supply circuit of the water supply fitting 7, the pressure reducing valve 8, the water supply amount sensor 9, the hot water storage tank 10, the hot water mixing valve 12, the hot water supply fitting 13, and the faucet 14 is started (step 65). During hot water operation, hot water is supplied with water pressure from the water supply source.

  Next, when the faucet is closed and the use of hot water is completed (step 66), the hot water supply is stopped, the hot water / water mixing valve 12 is set to a predetermined position, and the hot water supply operation is stopped (step 67).

  Further, the operation control means 51 detects the hot water storage temperature and the amount of hot water stored in the hot water storage tank 10 by the tank temperature sensors 10a, 10b, 10c and 10d after the hot water supply operation (step 65) and after the hot water supply operation is stopped (step 67). The remaining hot water amount is determined (step 68).

  Normally, the remaining amount of hot water is not less than the specified amount and the boiling operation is not performed. However, when the amount of remaining hot water in the tank is less than the specified value, the tank boiling operation (step 69) is performed, and in the hot water storage amount determination (step 70), The tank boiling operation is terminated after the hot water storage temperature and the hot water storage volume reach the specified values (step 71).

  When the set time for starting the operation is reached, the boiling operation (step 61) is performed again so that the specified amount of stored hot water in the tank is reached.

  As described with reference to FIG. 2, the heating of the heat pump unit 30 is normally performed at midnight, and when there is a shortage, it is performed at daytime. Since noise may be a problem during midnight operation, the heat pump water heater of this embodiment has two modes, a normal operation mode and a save operation mode (silent operation mode), as operation modes during midnight operation. The charge mode can be changed according to the situation.

  Here, the normal operation mode is a mode in which all the refrigeration cycles are operated to perform boiling, and in the example of FIG. 1, an operation mode using both the refrigeration cycle a80 and the refrigeration cycle b90. In this normal operation mode, a high boiling capacity can be obtained while the generated noise is relatively high.

  On the other hand, the save operation mode is a mode in which a part of the refrigeration cycle is operated and the rest is stopped and heated up. In the example of FIG. 1, the refrigeration cycle a80 is operated and the refrigeration cycle b90 is stopped. It is an operation mode. According to this example, since the refrigeration cycle is halved, the heating capacity is reduced to a predetermined half, and the operation sound can be reduced by about -3 dB. Moreover, it is preferable that the refrigeration cycle to be operated and stopped is alternately operated and stopped in consideration of the life of the parts. Alternatively, it is best to store each operation time so that the operation time of each refrigeration cycle is memorized and equal operation time is stored. In FIG. 1, the configuration has two refrigeration cycles. However, a hot water heater having three or more refrigeration cycles can employ the same save operation mode and stop one or more refrigeration cycles. Thus, noise can be reduced.

  By preparing the save operation mode explained above, when driving in a quiet environment late at night, select the save operation mode with the remote control, and adjust the amount of noise generation according to the environment In addition, it is possible to provide a water heater that avoids the late-night noise problem of a heat pump water heater that is rarely regarded as a problem.

  Next, a water heater of Example 2 will be described. Description of points common to the first embodiment is omitted.

  For example, in the case of a water heater installed in a supermarket or a nursing home, for example, the location where a user interface, for example, a remote controller is installed, and the location where the hot water is actually used are mostly different. In the case of such a facility, a facility manager or the like who manages the entire facility grasps the operation state of the water heater together with the air conditioner and sets various remote controllers so as not to run out of hot water. Therefore, it is necessary to prevent erroneous setting and to prevent easy operation. Therefore, in order to prevent erroneous setting by the remote controller, a special remote controller operation (for example, simultaneously pressing three buttons on the remote controller) is performed so that the setting can be performed.

  For example, as shown in FIG. 3, when two or more, for example, three buttons of different types are pressed at the same time, it is possible to proceed to a menu for selecting an operation mode and to select a save operation mode. Thereby, the operation which a user does not intend can be prevented reliably.

  Next, a water heater of Example 3 will be described. Description of points common to the first and second embodiments is omitted.

  The heat pump unit used in Example 3 is a heat pump unit that uses carbon dioxide as a refrigerant and has a supercritical cycle refrigeration cycle. A heat pump water heater employing a supercritical cycle using carbon dioxide as a refrigerant has a very high pressure (high pressure) compared to the R410A refrigerant. For this reason, further careful consideration is required for the driving sound. In addition, a heat pump water heater that uses carbon dioxide refrigerant is an environment-friendly and energy-saving device. By applying the configuration of the third embodiment, further energy saving can be achieved.

  DESCRIPTION OF SYMBOLS 1a, 1b ... Compressor 2 ... Water refrigerant | coolant heat exchanger 4a, 4b ... Pressure-reducing device 5a, 5b ... Air heat exchanger 6a, 6b ... Blower 7 ... Water supply metal fitting 8 ... Pressure-reducing valve 9 ... Feed water quantity sensor 10 ... Tank 12 ... Hot water mixing valve 13 ... Hot water supply fitting 14 ... Faucet 15 ... Circulation pump 20 ... Hot water temperature sensor 21 ... Incoming water temperature sensor 22 ... Compressor discharge temperature sensor 23 ... Outside air temperature sensor 30 ... Heat pump unit 40 ... Hot water storage unit 50 ... Remote control 51 ... Hot water storage Unit control means 52 ... Heat pump unit control means 80 ... Refrigeration cycle a 90 ... Refrigeration cycle b

Claims (3)

A heat pump unit with multiple refrigeration cycles;
A hot water storage unit for storing hot water boiled using the heat pump unit;
In a heat pump water heater equipped with
The heating operation in the heat pump unit is
Normal operation mode in which boiling is performed using all refrigeration cycles,
Save operation mode that uses some refrigeration cycles to boil,
A heat pump water heater characterized by comprising: In the heat pump water heater according to claim 1,
Furthermore, it has a remote control with a plurality of buttons,
A selection menu is displayed when multiple buttons on the remote control are pressed simultaneously.
A heat pump water heater, wherein the save operation mode can be selected. In the heat pump water heater according to claim 1 or 2,
Using carbon dioxide as a refrigerant in the refrigeration cycle,
A heat pump water heater having a refrigeration cycle of a supercritical cycle.