JP3914830B2 - Heat pump water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat pump type water heater.
[0002]
[Prior art]
Conventional hot water heaters are equipped with a combustion water heater or a large-capacity hot water tank that does not have a hot water tank and burns gas, etc., and instantly boiles water with its powerful combustion heat to supply hot water. There were electric water heaters that used cheap electricity at nighttime 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. And recently, a heat pump type water heater that is said to be more energy efficient than an electric water heater has begun to spread.
[0003]
The heat pump water heater is equipped with a large-capacity hot water storage tank, similar to an electric water heater, and uses hot electricity at night to boil hot water in the heat pump circuit and store it in the hot water storage tank. However, since the heat source uses the state change of the refrigerant in the heat pump circuit as the heat source, it is several times more energy efficient than electric heater heating and does not burn gas etc. It is said to be an environmentally friendly water heater.
[0004]
As such a conventional heat pump type water heater, there is one disclosed in Japanese Patent Application Laid-Open No. 2001-208434, and will be described with reference to FIG.
[0005]
A conventional heat pump type hot water heater includes a refrigerant circulation circuit in which a compressor 1, a refrigerant-to-water heat exchanger 2, a decompression device 3, and an evaporator 4 are sequentially connected, a hot water tank 5, a circulation pump 6, and a refrigerant-to-water heat exchanger. 2, a discharge temperature detection means 12 that detects the discharge temperature of the compressor 1, an outside air temperature detection means 17 that detects the outside air temperature, and the temperature of the water-side outlet of the refrigerant-to-water heat exchanger 2. The boiling temperature detecting means 8 for detecting the temperature, the inlet temperature detecting means 10 for detecting the temperature of the water side inlet of the refrigerant-to-water heat exchanger 2, and the first storage means 13 for storing a predetermined target discharge temperature. And the second storage means 14 storing the lower limit value (minimum valve opening) of the opening of the decompression device 3, and the opening of the decompression device 3 to be set to a preset target discharge temperature. The control means 11 and the pump control means 9 for controlling the rotational speed of the circulation pump 6 are provided. Further provided with a minimum valve opening to opening of the pressure reducing device 3 is the outside air temperature obtained by a signal from the outside air temperature detection means 17 that so as to vary the minimum valve opening of the pressure reducing device 3.
[0006]
In such a conventional heat pump type hot water heater, the pump control means 9 controls the number of revolutions of the circulation pump 6 by a signal from the boiling temperature detection means 8, and the outlet water temperature (boiling temperature) of the refrigerant-to-water heat exchanger 2. When the temperature detected by the inlet temperature detection means 10 reaches a set value, the operation of the circulation pump 6 and the heat pump circuit is stopped. When the hot water stored in the hot water tank 5 is discharged from the hot water pipe 15a, the hot water is supplied to the hot water tank 5 from the water supply pipe 16a. Further, the control means 11 is based on the signals from the discharge temperature detection means 12 and the outside air temperature detection means 17, the target discharge temperature of the first storage means 13, and the minimum valve opening of the second storage means 14. The valve opening degree of the decompression device 3 is controlled.
[0007]
[Problems to be solved by the invention]
However, in the conventional heat pump type hot water heater, the capacity of the compressor 1 is fixed. Therefore, when the user wants to boil hot water quickly, for example, or when he wants to boil hot water without rushing and saving power consumption. In such a case, it was not possible to deal with such cases, and there was a problem in usability. In addition, there is a time zone in which hot water is used a lot in one day and a time zone in which the hot water is not used so much, and if the operation capability of the compressor 1 remains fixed, there is a problem that hot water cannot be efficiently supplied to these. there were. Furthermore, since the outside air temperature changes greatly depending on the season, the heat exchange capacity of the evaporator 4 and the temperature of the water used change greatly accordingly. As a result, as shown in FIG. 7, when the outside air temperature is low, the boiling time becomes long (it takes 30 seconds in the illustrated example), and there is a problem that the hot water temperature does not rise by a predetermined time. When the temperature is high, an overshoot phenomenon that greatly exceeds the set temperature occurs during boiling, and hot water (hot water as high as 2 ° C. with respect to the set temperature 42 ° C. in the illustrated example) is supplied.
[0008]
In addition, the conventional heat pump water heater requires that a large amount of hot water be stored in a hot water storage tank, so that the heat pump circuit is not used where the efficiency is sufficiently high, and the surface of a large hot water tank Therefore, there is a problem that a lot of heat is radiated and energy is wasted, which causes a decrease in energy efficiency. Along with having a large-capacity hot water storage tank, there is a problem that a large installation space is required and the transportation and installation of the water heater are troublesome.
[0009]
The purpose of the present invention, even when the outside air temperature changes is possible appropriately hot water supply start-up time and the hot water supply temperature, the user uses heat pump water heater capable of performing a hot water supply operation corresponding efficient for the purpose of It is to provide.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a heat pump type hot water heater of the present invention includes a compressor, a refrigerant-to-water heat exchanger, a decompression device, a heat pump circuit having an evaporator, and hot water heated by the refrigerant-to-water heat exchanger. A hot water storage tank that stores water , a second hot water supply circuit that can supply water supplied from a water supply pipe to the outlet by heating with the refrigerant to water heat exchanger, and the refrigerant to water heat in the second hot water supply circuit A first hot water supply circuit that supplies hot water from the hot water tank to the hot water outlet until the temperature at the outlet portion of the exchanger rises, and water heat in the refrigerant-to-water heat exchanger during operation by the second hot water supply circuit in the boiling temperature of the outlet water exchanger has a configuration and a control unit for controlling the capacity of said compressor to a predetermined temperature.
A more preferable specific configuration example of the present invention is as follows.
(1) It is provided with an outside air temperature detecting means, and the control unit controls the capacity of the compressor based on the output of the outside air temperature detecting means.
(2) Hot water supply temperature detection means for detecting the temperature of hot water supplied to the hot water outlet, and a hot water supply temperature command circuit for holding a hot water supply set temperature set by a user, wherein the control unit includes the hot water supply temperature. Controlling the capacity of the compressor in accordance with a deviation between the temperature detected by the detecting means and the hot water supply set temperature.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol as the prior art example in a present Example shows the same thing or an equivalent.
[0012]
In FIG. 1, a heat pump type hot water heater includes a heat pump circuit 31 formed by a heat pump type refrigeration cycle, a hot water supply unit 32 heated by the heat pump circuit 31, and a control unit 33 that controls the heat pump circuit 31 and the hot water supply unit 32. It is configured to accommodate these in a single box.
[0013]
The heat pump circuit 31 includes a variable capacity compressor 1 that compresses a low-temperature and low-pressure refrigerant and discharges it as a high-temperature and high-pressure refrigerant, and a condenser 2a that heat-exchanges the discharged refrigerant with the water heat exchanger 2b to condense it. The decompression device 3 for decompressing the condensed refrigerant and the evaporator 4 for evaporating the decompressed refrigerant by exchanging heat with the outside air are connected by a refrigerant pipe. Here, the rotation speed of the compressor 1 is controlled from a low speed (for example, 2200 rpm) to a high speed (for example, 8000 rpm) by PWM control, voltage control (for example, PAM control), and a combination control thereof. It has become.
[0014]
The hot water supply section 32 is a small-capacity hot water storage tank 5 for storing a small amount of hot water of about 60 L, a water heat exchanger 2 b that is heated by heat exchange with the condenser 2 a, and water heat exchange of the water in the hot water storage tank 5. A circulation pump 6 that circulates through the vessel 2b, a hot water supply pipe 16 that supplies water to the hot water storage tank 5 and the water heat exchanger 2b, and a hot water discharge pipe 15 that supplies hot water from the hot water storage tank 5 and the water heat exchanger 2b. It is configured. The condenser 2a and the water heat exchanger 2b constitute the refrigerant-to-water heat exchanger 2.
[0015]
Here, the hot water supply unit 32 includes a hot water storage circuit including the hot water storage tank 5, the circulation pump 6 and the water heat exchanger 2 b, a first hot water supply circuit including the water supply pipe 16, the hot water storage tank 5 and the hot water supply pipe 15, and the water supply pipe 16. The water heat exchanger 2b and the second hot water supply circuit including the hot water supply pipe 15 are formed to be switchable. In addition, illustrations of sensors and control valves necessary for these switching are omitted.
[0016]
The control unit 33 detects the state of the water heater, selects a hot water storage circuit, a first hot water supply circuit, and a second hot water supply circuit, and controls the compressor 1 and the pressure reducing device 3 of the heat pump circuit 31. And a function of controlling the circulation pump 6 of the hot water supply section 32. More specifically, the control unit 33 includes a compressor rotational speed detection means 21, a hot water supply 8 temperature detection means for detecting the temperature of the hot water supply pipe 15, and an inlet temperature detection means for detecting the inlet temperature of the water heat exchanger 2b. 10, an outside air temperature detecting means 17 for detecting the outside air temperature, a temperature command circuit 22, and a control means 11 for controlling the compressor 1 and the circulation pump 6 through a drive circuit. The outside air temperature detecting means 17 is provided in the ventilation path of the evaporator 4 and detects the outside air temperature.
[0017]
Next, an outline of the operation of the heat pump type water heater having such a configuration will be described.
[0018]
First, the hot water storage operation to the hot water tank 5 will be described. In the hot water storage operation, the temperature at the outlet of the hot water storage tank 5 is detected when hot water is not discharged, and when the detected temperature is a predetermined temperature (for example, 60 ° C.) or less, the heat pump circuit 31 and the hot water supply unit 32 are operated to store hot water. This operation is performed to store hot water at a predetermined temperature or higher in the tank 5.
[0019]
The operation of the heat pump circuit 31 at this time is performed when the compressor 1 is operated, and the refrigerant of the heat pump circuit 31 is supplied to the condenser at a high temperature and a high pressure in the compressor 1, and the water heat exchange is performed in the condenser 2a. The water used in the vessel 2b is heated and condensed to reach the decompression device 3, decompressed by the decompression device 3 to the evaporator 4, and then absorbed by the evaporator 4 from the outside air blown by the fan and evaporated. Return to 1.
[0020]
On the other hand, the operation of the hot water supply section 32 in the hot water storage operation is performed by operating the circulation pump 6, and the water in the hot water storage tank 5 is sent to the water heat exchanger 2 b and heated by the condenser 2 a, The hot water supplied from the exchanger 2b is circulated through the hot water storage circuit so that the hot water is stored in the hot water storage tank 5. As a result, the water in the hot water tank 5 is heated to around 60 ° C. and stored. When the entire hot water storage tank 5 reaches a predetermined temperature or higher, the operation of the circulation pump 6 is stopped and the hot water storage operation ends.
[0021]
When hot water from the hot water outlet 15a starts in this state, a first hot water supply circuit including the water supply pipe 16, the hot water storage tank 5, and the hot water supply pipe 15 is formed, and hot water in the hot water storage tank 5 is discharged from the hot water outlet 15a. At the same time, the operation of the heat pump circuit 31 is also started. When the water of the water heat exchanger 2b is heated by this operation and the temperature of the outlet portion rises, a second hot water supply circuit including the water supply pipe 16, the water heat exchanger 2b, and the hot water supply pipe 15 is formed. Transition to hot water supply by hot water supply circuit. As a result, the hot water storage tank 5 has a small capacity and functions sufficiently, preventing waste of hot water in the hot water tank 5, reducing waste of heat energy radiated from the surface of the hot water tank 5, and reducing the size and size. A heat pump type hot water heater that is light in weight and excellent in transportability and installation can be obtained. Moreover, the hot water supply temperature from the water heat exchanger 2b by the second hot water supply circuit may be an actual use temperature that is significantly lower than the hot water storage temperature by the hot water storage circuit, and the efficiency of the heat pump circuit 31 by the second hot water supply circuit. Can be improved compared to hot water storage operation.
[0022]
Due to the formation of the second hot water supply circuit, the use water supplied from the water supply pipe 16 is heated by the water heat exchanger 2b, and the hot water discharged from the water heat exchanger 2b passes through the hot water supply pipe 15 and is discharged from the hot water outlet 15a. This state is continued until the hot water is finished.
[0023]
Next, specific control of the compressor 1 will be described with reference to FIGS.
[0024]
The control means 11 has a controller 11a and a compressor drive device 11b, and drives the compressor drive device 11b based on signals from the controller 11a and the compressor rotation speed detection means 21 to control the rotation speed of the compressor 1. Drive while.
[0025]
The controller 11a receives an outside air temperature variable k and a tapping temperature deviation ΔT, and calculates and outputs a target rotational speed N ^* that is a command value based on both the k and ΔT. Based on the command value N ^* and the rotational speed N detected by the compressor rotational speed detection means 21, the compressor driving device 11b controls the rotational speed of the compressor 1 by PWM control in the low speed range and PAM control in the high speed range. Then, the hot water supply temperature of the water heat exchanger 2b (outlet water boiling temperature) is controlled to be substantially constant. The PAM control may be any control as long as the voltage is changed.
[0026]
The hot water temperature deviation ΔT is a temperature deviation between a hot water temperature setting value T _set (for example, 42 ° C.) preset by the hot water temperature command circuit 22 and the hot water temperature T _w detected by the hot water 8 temperature detecting means. This is a control value for controlling the hot water supply temperature from the exchanger 2b. As shown in FIG. 3, the controller 11a calculates and outputs a target rotational speed N * corresponding to the hot water supply temperature deviation ΔT. FIG. 3 shows an example when the outside air temperature Ta is 25 ° C.
[0027]
Further, the outside air temperature variable k is a temperature deviation between the reference value Ta ^* and the outside air temperature Ta detected by the outside air temperature detecting means 17, and changes according to the outside air temperature Ta as shown in FIG. This is a control value for controlling the hot water supply temperature from the vessel 2b.
[0028]
Here, when the outside air temperature is detected as 25 ° C., the outside air temperature variable k is 1.0 from the characteristic diagram of FIG. As a result, the target rotational speed N * (for example, 5000 revolutions / minute) of the compressor 1 with respect to the hot water supply temperature deviation ΔT at the outside air temperature of 25 ° C. shown in FIG. 3 is calculated, and the hot water supply temperature from the water heat exchanger 2b is the hot water supply set temperature. The operation of the compressor 1 is started so as to approach (for example, 42 ° C.). When the hot water supply temperature from the water heat exchanger 2b rises due to the operation of the compressor 1, the hot water supply temperature deviation ΔT is reduced, and thereby the target rotational speed N * of the compressor 1 is reduced.
[0029]
Therefore, when the user wants to boil hot water quickly, for example, by increasing the hot water supply set temperature of the hot water supply temperature command circuit 22, the compressor 1 is started to operate at a high speed and the hot water supply temperature is raised in a short time. In the case where it is desired to boil hot water without urgently saving power consumption, the compressor 1 can be started from a low speed and efficiently operated by lowering the hot water temperature setting temperature of the hot water temperature command circuit 22. . Moreover, since the operation capability of the compressor 1 is variably controlled in both the time zone in which a lot of hot water is used and the time zone in which the hot water is not used much, hot water can be supplied efficiently.
[0030]
In addition, when the outside air temperature Ta is low, the heat collection efficiency of the refrigerant-to-water heat exchanger 5 is increased by controlling the rotation speed of the compressor 1 according to the controller constant k · ΔT, which is set as shown in FIG. When the temperature rises to 42 ° C., it will boil faster than in the past (in the example shown, it will boil in about 15 seconds). At this time, the target rotational speed N * of the compressor 1 changes in accordance with the hot water supply temperature deviation ΔT in a range of 8000 to 2200 revolutions / minute, and the hot water control that has been consumed for 30 seconds in the conventional example is about approximately in this embodiment. The hot water temperature can reach the set value at half the speed of 15 seconds. Furthermore, when the outside air temperature Ta is high, as shown in FIG. 5, the overheating temperature of the hot water supply temperature can be suppressed to an overshoot error ± 1 ° C. or less with respect to the hot water supply set value 42 ° C. Thereby, the unpleasant feeling that a user hits hot hot water at the time of hot water can be surely eliminated.
As described above, according to the present embodiment, it is possible to obtain a heat pump type water heater capable of efficiently performing a hot water supply operation corresponding to a user's purpose of use.
In addition, a hot water supply start-up time and a hot water supply temperature can be made appropriate even when the outside air temperature changes, and a heat pump type hot water heater capable of efficiently performing a hot water supply operation corresponding to the user's purpose of use can be obtained.
In addition, to obtain a heat pump type hot water heater that is energy efficient, small and lightweight, excellent in transportability and installation, can prevent hot water shortage, and can efficiently perform hot water supply operation corresponding to the user's purpose of use. Can do.
[0031]
【The invention's effect】
As is apparent from the description of the above embodiments, according to the present invention, the hot water supply start-up time and the hot water supply temperature can be appropriately set, and the heat pump type capable of efficiently performing the hot water supply operation corresponding to the user's purpose of use. A water heater can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a heat pump type water heater according to an embodiment of the present invention.
FIG. 2 is an operation control block diagram of the compressor of FIG.
3 is a characteristic diagram of a target rotation speed with respect to a hot water supply temperature deviation of the heat pump type hot water heater of FIG. 1. FIG.
4 is a characteristic diagram of hot water temperature deviation with respect to the outside air temperature of the heat pump type hot water heater of FIG. 1. FIG.
FIG. 5 is a characteristic diagram of a boiling temperature of the heat pump type water heater of FIG. 1;
FIG. 6 is a configuration diagram of a conventional heat pump type water heater.
7 is a characteristic diagram of boiling temperature of the heat pump type water heater of FIG. 6. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Refrigerant to water heat exchanger, 2a ... Condenser, 2b ... Water heat exchanger, 3 ... Decompression device, 4 ... Evaporator, 5 ... Hot water tank, 6 ... Circulation pump, 8 ... Hot water temperature Detecting means, 10 ... Inlet temperature detecting means, 11 ... Control means, 11a ... Controller, 11b ... Compressor driving device, 15 ... Outlet port, 16 ... Water supply port, 17 ... Outside air temperature detecting means, 21 ... Detection of compressor speed Means, 22 ... Hot water supply temperature command circuit, 23 ... Controller, 31 ... Heat pump circuit, 32 ... Hot water supply unit, 33 ... Control unit.

Claims (3)

A heat pump circuit having a compressor, a refrigerant-to-water heat exchanger, a decompressor, and an evaporator;
A hot water storage tank for storing hot water heated by the refrigerant-to-water heat exchanger ;
A second hot water supply circuit capable of heating the water supplied from the water supply pipe with the refrigerant-to-water heat exchanger and supplying the water to the outlet;
A first hot water supply circuit for supplying hot water from the hot water storage tank to the hot water outlet until the temperature of the outlet portion of the refrigerant-to-water heat exchanger in the second hot water supply circuit rises;
And a control unit for boiling temperature of the outlet water of the water heat exchanger in the refrigerant-water heat exchanger to control the capacity of said compressor to a predetermined temperature during operation by the second hot water supply circuit Ruhi Toponpu water heater. In claim 1,
An outside air temperature detecting means,
The control unit, on the basis of the output of the outside air temperature detection means, heat pump water heater characterized by a Turkey to control the capacity of said compressor. In claim 1 or 2,
Hot water supply temperature detection means for detecting the temperature of hot water supplied to the hot water outlet;
A hot water supply temperature command circuit for holding a hot water supply set temperature set by a user,
The said control part controls the capability of the said compressor according to the deviation of the temperature detected by the said hot water supply temperature detection means, and the said hot water supply preset temperature , The heat pump type hot water heater characterized by the above-mentioned.

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