JP2002318016A - Heat pump type eater heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the heat-up time of a water heater by shortening a time, until the operation of an expansion valve is stabilized (the time until an objective opening degree is achieved). SOLUTION: Initial treatment is applied on the expansion valve, before starting a system by a control unit. The initial treatment operates an initial opening degree (the objective opening degree of the expansion valve, when hot-water supplying operation at ΔT≈10 deg.C is stabilized) from a map, for example, according to the outdoor air temperature and the feed water temperature, then the system is started, after operating the expansion valve to the operated initial opening degree. According to this method, the expansion valve is set at the objective opening degree (initial opening degree) at a time point when hot-water supplying operation is started, whereby the time from the starting of a compressor until the operation of the expansion valve is stabilized (until the hot-water supplying operation is stabilized at ΔT≈10 deg.C) can be markedly shortened, as compared with the conventional expansion valve control (the expansion valve is operated uniformly from a given initial opening degree), whereby the heat-up time of the water heater can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat pump type water heater using a supercritical heat pump cycle as heating means for a fluid to be heated.

[0002]

2. Description of the Related Art Japanese Patent Application No.
000-311142. In this water heater, a heat pump cycle is provided with a variable expansion valve (an expansion valve whose valve opening can be adjusted), and the high pressure in the cycle is controlled by the opening of the expansion valve. Specifically, the expansion valve is opened so that the temperature difference between the inlet-side feedwater temperature and the outlet-side refrigerant temperature of the water heat exchanger that exchanges heat between the used water and the refrigerant becomes a predetermined target temperature difference ΔT. High pressure control is performed by adjusting the degree.

[0003]

However, in the expansion valve control of the prior application, the initial opening of the expansion valve is uniformly constant (3) regardless of the environmental conditions (outside air temperature, supply water temperature) where the water heater is placed.
00 Step), and operates so as to gradually stabilize to the target temperature difference ΔT after the hot water supply operation is started. For this reason, the operation time until the expansion valve reaches the target opening varies depending on external conditions. For example, in the winter (target opening 100 Step) than in the summer (target opening 250 Step),
The operation time of the expansion valve until reaching the target opening degree becomes long.

[0004] As a result, at the start of the hot water supply operation, the target capacity arrival time and the target hot water temperature arrival time are delayed.
There was a problem that the boiling time of the water heater was delayed. The present invention has been made based on the above circumstances, and shortens the time required for the operation of the expansion valve to stabilize (the time required to reach the target opening), thereby delaying the boiling time of the water heater. Is to reduce.

[0005]

According to a first aspect of the present invention, a controller sets a target opening degree at the time of stable hot water supply operation determined from at least one of an outside air temperature and a supply water temperature as an initial opening degree of the expansion valve. I do. And before starting the compressor,
After operating the expansion valve to the initial opening, the compressor is started to start the hot water supply operation.

According to the present invention, since the expansion valve is already set to the target opening when the hot water supply operation is started, the time from the start of the compressor until the operation of the expansion valve is stabilized is reduced. Can shorten the time required for boiling water heaters. Further, power consumption can be reduced by shortening the hot water supply operation time (operation time of the compressor and the like), and the durability of the system functional product can be improved.

[0007] (Means of the present invention) The control device operates the expansion valve to a predetermined initial opening before starting the compressor, and after starting the compressor, from the initial opening to the intermediate opening. The opening of the expansion valve is controlled at the first operating speed, and after reaching the intermediate opening, the opening of the expansion valve is controlled at a second operating speed smaller than the first operating speed up to the target opening. The intermediate opening is set between the target opening and the initial opening at the time of stable hot water supply operation obtained from at least one of the outside air temperature and the supply water temperature.

According to the present invention, the opening of the expansion valve can be controlled from the initial opening to the intermediate opening at the first operation speed higher than the second operation speed, so that the conventional expansion valve control (from the initial opening to the intermediate opening) can be performed. The operation time required for the expansion valve to stabilize at the target opening can be reduced as compared to the case where the opening of the expansion valve is gradually controlled until the target opening is stabilized. As a result, the boiling time of the water heater can be reduced. Further, power consumption can be reduced by shortening the hot water supply operation time (operation time of the compressor and the like), and the durability of the system functional product can be improved.

(3) The control device predicts an expansion valve target opening during the current hot water supply operation stabilization based on the expansion valve opening during the previous hot water supply operation stabilization, and expands the target opening. Set as the initial opening of the valve. Then, before starting the compressor, the expansion valve is operated to the initial opening degree, and then the compressor is started to start the hot water supply operation.

According to the present invention, since the expansion valve is already set to the target opening when the hot water supply operation is started, the time from the start of the compressor until the operation of the expansion valve is stabilized is reduced. Can shorten the time required for boiling water heaters. Further, power consumption can be reduced by shortening the hot water supply operation time (operation time of the compressor and the like), and the durability of the system functional product can be improved.

(4) The control device operates the expansion valve to a predetermined initial opening before starting the compressor, and based on the opening of the expansion valve at the time of the stable hot water supply operation on the previous day, this time. Predict the expansion valve target opening when the hot water supply operation is stable, set an intermediate opening between the target opening and the initial opening, start the compressor, and start the compressor from the initial opening to the intermediate opening. The opening of the expansion valve is controlled at the first operation speed, and after reaching the intermediate opening, the opening of the expansion valve is controlled at the second operation speed smaller than the first operation speed until the target opening.

According to the present invention, the opening of the expansion valve can be controlled from the initial opening to the intermediate opening at the first operating speed higher than the second operating speed. The operation time required for the expansion valve to stabilize at the target opening can be reduced as compared to the case where the opening of the expansion valve is gradually controlled until the target opening is stabilized. As a result, the boiling time of the water heater can be reduced. Further, power consumption can be reduced by shortening the hot water supply operation time (operation time of the compressor and the like), and the durability of the system functional product can be improved.

According to a fifth aspect of the present invention, in the heat pump type water heater according to the third or fourth aspect, the control device has a storage circuit for storing an expansion valve opening when the hot water supply operation is stable.
This storage circuit updates the expansion valve opening when the hot water supply operation is stable for each operation. Thus, the expansion valve opening during the next hot water supply operation stabilization can be predicted as the target opening based on the expansion valve opening during the current hot water supply operation stabilization.

According to a sixth aspect of the present invention, in any one of the heat pump type water heaters according to the first to fifth aspects, the higher the outside air temperature is, the larger the target opening of the expansion valve is set.

(Means of Claim 7) In any one of the heat pump type water heaters according to any one of claims 1 to 5, the target opening degree of the expansion valve is set to be larger as the supply water temperature becomes higher.

In the heat pump type water heater according to any one of the first to seventh aspects, the temperature difference between the utilization water flowing into the water heat exchanger and the refrigerant flowing out of the water heat exchanger is determined. High-pressure control in the cycle is performed so as to attain the target temperature difference ΔT. For example, when the opening of the expansion valve is reduced, the flow path resistance of the refrigerant increases, so that the pressure of the high-pressure refrigerant discharged from the compressor increases. Conversely, when the opening of the expansion valve is increased, the flow path resistance of the refrigerant decreases,
The refrigerant pressure on the high pressure side discharged from the compressor decreases. That is, the opening degree of the expansion valve is adjusted to control the high pressure in the cycle so that the target temperature difference ΔT is obtained.

[0017] (unit of claim 9) In any one of the heat pump water heater according to claim 8, when using CO ₂ as refrigerant in the heat pump cycle, CO ₂
Since the critical pressure is low, the refrigerant pressure on the high pressure side can be increased to the critical pressure or higher. Thereby, a high hot water supply temperature (for example, 9
0 ° C.).

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a heat pump type water heater according to the present invention will be described with reference to the drawings. FIG. 1 is a system configuration diagram of the heat pump type water heater 1. As shown in FIG. 1, a heat pump type water heater 1
A heat pump cycle (to be described later), which is used in a hot water supply system in which water used is taken out of the tank 2 at the time of use and the temperature of the water is adjusted and supplied to a user, A control device 3 for controlling the operation of the entire hot water supply system is provided.

The tank 2 is made of metal (for example, stainless steel) having excellent corrosion resistance and has a heat insulating structure, and can keep hot water used for a long time. The water stored in the tank 2 may be used directly in a kitchen, a bath, or the like, but may be used as a heat source other than for hot water supply, for example, for floor heating, indoor air conditioning, and the like. This tank 2
Is connected via a water side pipe 4 to a water supply passage of a water heat exchanger 5 described below. One end of the water-side pipe 4 is connected to an outlet port 2 a provided at a lower portion of the tank 2, and the other end is connected to an inlet port 2 b provided at an upper portion of the tank 2.

The water-side pipe 4 is provided with an electric pump 6 for circulating use water between the tank 2 and the water heat exchanger 5. This electric pump 6 can adjust the amount of circulating water according to the number of rotations of a built-in motor. The heat pump cycle uses low critical pressure carbon dioxide (C
By using O ₂ ) as the refrigerant, the pressure of the refrigerant on the high pressure side is increased to a value equal to or higher than the critical pressure. As shown in FIG. 1, this heat pump cycle includes a compressor 7, a water heat exchanger 5, an expansion valve 8, an air heat exchanger 9, an accumulator 10, and the like.

The compressor 7 has a built-in motor driven by an inverter circuit 11, and the rotation of the motor causes
The sucked gas refrigerant is compressed and discharged to a critical pressure or higher. The water heat exchanger 5 exchanges heat between the high-pressure gas refrigerant discharged from the compressor 7 and the use water, and as shown by arrows in FIG. Are facing each other.

The expansion valve 8 has a structure capable of adjusting the valve opening, and reduces the pressure of the refrigerant cooled by the water heat exchanger 5 in accordance with the valve opening. A method for controlling the expansion valve 8 will be described later. The air heat exchanger 9 receives the air blown by the fan 12 and evaporates the refrigerant decompressed by the expansion valve 8 by heat exchange with the outside air. The accumulator 10 stores the surplus refrigerant in the cycle by separating the refrigerant evaporated in the air heat exchanger 9 into gas and liquid, and causes the compressor 7 to suck only the gas-phase refrigerant.

In this hot water supply system, as shown in FIG.
A water temperature sensor 13 for detecting the temperature Tw of the used water flowing into the water heat exchanger 5, a refrigerant temperature sensor 14 for detecting the temperature Tr of the refrigerant flowing out of the water heat exchanger 5, and an outside air temperature sensor for detecting the outside air temperature Tam 15 etc., and each of the sensors 13-1
The information (sensor signal) detected at 5 is output to the control device 3.

The control device 3 calculates the temperature difference between the water used to flow into the water heat exchanger 5 and the refrigerant flowing out from the water heat exchanger 5 so that the heat pump cycle can be operated efficiently.
The high-pressure side pressure in the cycle is controlled based on this temperature difference. Specifically, an optimum temperature difference (referred to as a target temperature difference ΔT) that can be operated near the highest cycle efficiency is obtained, and the opening degree of the expansion valve 8 is adjusted so as to obtain the target temperature difference ΔT (for example, 10 ° C.). It is electrically controlled (see FIG. 2).

Next, the processing procedure of the controller 3 for controlling the hot water supply operation will be described with reference to the flowchart shown in FIG. Step 10: The start switch is turned on and the control device 3 is started. Step 20: The initial processing (described later) of the expansion valve 8 is executed. Step30: Start the system. Here, the compressor 7, the fan 12, the electric pump 6, and the like are started. Step40: Start hot water supply operation.

The operation of the hot water supply operation will be briefly described. In the heat pump cycle, the refrigerant compressed to a high temperature and a high pressure by the compressor 7 is supplied to the water heat exchanger 5, radiates heat in the water heat exchanger 5, lowers the temperature, and then is depressurized by the expansion valve 8. The decompressed refrigerant is sent to the air heat exchanger 9, absorbs heat from the outside air in the air heat exchanger 9, evaporates, is separated into gas and liquid by the accumulator 10, and then only the gas refrigerant is sucked into the compressor 7. . On the other hand, the water used in the tank 2 is supplied from the outlet port 2 a by the electric pump 6 to the water heat exchanger 5 through the water side pipe 4.
After being heated by the heat exchange with the high-temperature refrigerant in the water heat exchanger 5, the water flows into the tank 2 again from the inlet port 2b through the water side pipe 4 and is stored therein.

(First Embodiment) Next, the initial process (Step 20) of the expansion valve 8 will be described. Step21… Read the outside air temperature and feed water temperature. In this case, the outside air temperature and the water supply temperature at the time of the previous operation may be read from the storage circuit built in the control device 3 and used. Step 22: The initial opening of the expansion valve 8 is calculated. The initial opening degree is a target opening degree of the expansion valve 8 when the hot water supply operation is stabilized at ΔT ≒ 10 ° C., for example, from a map shown in FIG. The calculation is performed by the calculation circuit included in. Step 23: The expansion valve 8 is operated to the initial opening degree.

In this embodiment, the expansion valve 8 is subjected to initial processing before the system is started, so that the expansion valve 8 is already at the target opening (initial opening) at the time of starting the hot water supply operation.
Is set to Thus, even if the target opening of the expansion valve 8 differs for each season, the target opening can be set to a target opening corresponding to the outside air temperature and the supply water temperature at that time. As a result, as compared with the conventional expansion valve control (the expansion valve 8 operates from a uniform initial opening), the operation of the expansion valve 8 is stabilized after the compressor 7 is started (hot water supply at ΔT ≒ 10 ° C.). The time until the operation becomes stable) can be greatly reduced, and the boiling time of the water heater 1 can be reduced.

Further, the hot water supply operation time (operating time of the compressor 7, etc.) until the target hot water supply capacity is obtained can be shortened.
The power consumption can be reduced and the durability of the system functional product can be improved. In the present embodiment, the target opening degree of the expansion valve 8 is obtained according to the outside air temperature and the supply water temperature. However, the target opening degree of the expansion valve 8 is determined using only one of the outside air temperature and the supply water temperature as a parameter. You may ask.

(Second Embodiment) This embodiment is a second embodiment relating to the initial processing of the expansion valve 8, and is an example in which the operation speed until the expansion valve 8 is stabilized at the target opening degree is controlled in two stages. It is. The control device 3 sets an initial opening, an intermediate opening, and a target opening of the expansion valve 8, controls the initial opening to the intermediate opening at a first operating speed, and controls the intermediate opening to the target opening. Are controlled at the second operation speed. The intermediate opening is set between the initial opening (different from the target opening of the expansion valve 8 at which the hot water supply operation is stabilized) and the target opening. The target opening is calculated from a map (see FIG. 4) or an arithmetic circuit according to the outside air temperature and the supply water temperature, as in the first embodiment.

Hereinafter, the operation of this embodiment will be specifically described. Before starting the system, the expansion valve 8 is previously operated to a certain initial opening. Next, the system is started to start the hot water supply operation. In this hot water supply operation, as shown in FIG.
From the initial opening to the intermediate opening, the opening of the expansion valve 8 is controlled at the first operating speed (characteristic A in the figure), and after reaching the intermediate opening, the second operating speed (however, up to the target opening). , The first operation speed> the second operation speed: the characteristic shown by B in FIG.

According to this embodiment, the expansion valve 8 is operated at the first operation speed higher than the second operation speed from the initial opening to the intermediate opening.
Of the expansion valve 8 can be controlled in comparison with the conventional control valve control (the opening of the expansion valve 8 is gradually controlled from the initial opening to the target opening until the opening is stabilized). It is possible to shorten the operation time until the temperature becomes stable. As a result, the hot water supply operation time (operating time of the compressor 7 and the like) until the target hot water supply capacity is obtained can be reduced, so that power consumption can be reduced and the durability of the system functional product can be improved.

(Third Embodiment) This embodiment is a third embodiment relating to the initial processing of the expansion valve 8. In the first embodiment, the initial opening degree (target opening degree) of the expansion valve 8 is determined according to the outside air temperature and the supply water temperature. However, in the present embodiment, the expansion valve opening degree on the previous day when the hot water supply operation was stable was determined. In this example, the target opening of the control valve at the time of the stable hot water supply operation is predicted, and the target opening is set as the initial opening of the expansion valve 8.

The processing procedure of the control device 3 relating to the initial processing of the expansion valve 8 will be described below with reference to the flowchart shown in FIG. Step 210: After the start switch is turned on, the expansion valve opening when the hot water supply operation was stabilized the previous day is taken out of the storage circuit. Step220: Detect the outside air temperature and supply water temperature. The outside air temperature and the supply water temperature may be values detected the day before.

Step 230: The present expansion valve opening is calculated based on the expansion valve opening at the time of stable hot water supply operation on the previous day, taken out of the storage circuit, according to the outside air temperature or the supply water temperature. The expansion valve opening is a target opening of the expansion valve 8 when the hot water supply operation is stabilized at ΔT ≒ 10 ° C., and is calculated from, for example, a map shown in FIG. 7 according to the outside air temperature or the supply water temperature. Step 240: Operate the expansion valve 8 to the target opening (initial opening). The expansion valve opening when the hot water supply operation is stable last time stored in the storage circuit is updated by the expansion valve opening when the hot water supply operation is stable this time.

In this embodiment, as in the first embodiment, the expansion valve 8 is already set to the target opening (initial opening) at the time of starting the hot water supply operation. The time from the start of the compressor 7 until the operation of the expansion valve 8 stabilizes (the hot water supply operation stabilizes at ΔT ≒ 10 ° C.) can be greatly reduced, and the boiling time of the water heater 1 can be reduced. Can be shortened. Further, since the hot water supply operation time (operating time of the compressor 7 and the like) until the target hot water supply capacity is obtained can be reduced, power consumption can be reduced and the durability of the system functional product can be improved.

(Fourth Embodiment) This embodiment is a fourth embodiment relating to the initial processing of the expansion valve 8, and the second embodiment described above.
Similar to the embodiment, this is an example in which the operation speed until the expansion valve 8 is stabilized at the target opening degree is controlled in two stages. The difference from the second embodiment is that the target opening of the expansion valve 8 is predicted based on the opening of the expansion valve 8 when the hot water supply operation is stable the previous day. That is, the third
As in the embodiment, the expansion valve opening when the hot water supply operation is stabilized the previous day is taken out from the storage circuit, and the current expansion valve opening (target opening) is calculated according to the outside air temperature or the water supply temperature. In this case, it can be obtained from the map shown in FIG.

Thereafter, as in the second embodiment, the expansion valve 8 is operated to a predetermined initial opening before the system is started to start the hot water supply operation. In this hot water supply operation, the opening degree of the expansion valve 8 is controlled at the first operation speed (see FIG. 5) from the initial opening degree to the intermediate opening degree, and after reaching the intermediate opening degree, the hot water supply operation of the previous day is performed as described above. The opening of the expansion valve 8 is controlled at the second operation speed (first operation speed> second operation speed: see FIG. 5) up to the target opening predicted based on the expansion valve opening at the time of stability.

In this embodiment, similarly to the second embodiment, the opening of the expansion valve 8 can be controlled from the initial opening to the intermediate opening at a first operating speed higher than the second operating speed. The operation time required for the expansion valve 8 to stabilize at the target opening degree can be reduced as compared with the control valve control of the above. As a result, the hot water supply operation time (operating time of the compressor 7 and the like) until the target hot water supply capacity is obtained can be reduced, so that power consumption can be reduced and the durability of the system functional product can be improved.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a heat pump type water heater.

FIG. 2 is an explanatory diagram showing an example of control valve control.

FIG. 3 is a flowchart illustrating a processing procedure of a control device (first embodiment).

FIG. 4 is a map for obtaining an initial opening degree of an expansion valve.

FIG. 5 is an operation map showing a control method of the expansion valve (second and fourth embodiments).

FIG. 6 is a flowchart illustrating a processing procedure of a control device (third embodiment).

FIG. 7 is a map for obtaining a target opening of an expansion valve (third and fourth embodiments).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat pump type water heater 3 Control device 5 Water heat exchanger 7 Compressor 8 Expansion valve

Continued on the front page (72) Inventor Joji Kuroki 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Denso Corporation (72) Inventor Tomoaki Kobayakawa 1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Company (72) Inventor Kazutoshi Kusakari 1-3-1 Uchisaiwai-cho, Chiyoda-ku, Tokyo Tokyo Electric Power Company (72) Inventor Michiyuki Saikawa 2-6-1 Nagasaka, Yokosuka City, Kanagawa Prefecture Yokosuka Central Electric Power Research Institute In the laboratory

Claims (9)

[Claims] A compressor that compresses and discharges the sucked refrigerant; a water heat exchanger that exchanges heat between the refrigerant pressurized by the compressor and utilization water; and a refrigerant downstream of the water heat exchanger. An expansion valve provided in the passage and having an adjustable opening, before starting the compressor, after setting an initial opening of the expansion valve, after operating the expansion valve to the initial opening,
And a control device for starting the hot water supply operation by activating the compressor, wherein the control device sets the initial opening of the expansion valve to a value at the time of stable hot water supply operation obtained from at least one of the outside air temperature and the supply water temperature. A heat pump water heater characterized in that it is set to a target opening. 2. A compressor for compressing and discharging the sucked refrigerant, a water heat exchanger for exchanging heat between the refrigerant pressurized by the compressor and utilization water, and a refrigerant downstream of the water heat exchanger. An expansion valve provided in a passage and having an adjustable opening degree, before starting the compressor, after operating the expansion valve to a predetermined initial opening degree in advance, then starting the compressor to perform hot water supply operation. A control device for starting, the control device sets an intermediate opening between the target opening and the initial opening during the hot water supply operation stable obtained from at least one of the outside air temperature and the supply water temperature, After starting the compressor, the opening of the expansion valve is controlled at a first operating speed from the initial opening to the intermediate opening, and after reaching the intermediate opening, the second opening is performed to the target opening. Controlling the degree of opening of the expansion valve at a second operation speed lower than the first operation speed. Features a heat pump water heater. 3. A compressor for compressing and discharging the sucked refrigerant, a water heat exchanger for exchanging heat between the refrigerant pressurized by the compressor and utilization water, and a refrigerant downstream of the water heat exchanger. An expansion valve provided in the passage and having an adjustable opening, before starting the compressor, after setting an initial opening of the expansion valve, after operating the expansion valve to the initial opening,
A control device that starts the compressor to start the hot water supply operation.The control device calculates the expansion valve target opening during the current hot water supply operation based on the expansion valve opening when the hot water supply operation is stabilized the previous day. Predict,
A heat pump type water heater characterized in that the target opening is set as an initial opening of the expansion valve. 4. A compressor for compressing and discharging the drawn refrigerant, a water heat exchanger for exchanging heat between the refrigerant pressurized by the compressor and utilization water, and a refrigerant downstream of the water heat exchanger. An expansion valve provided in a passage, the opening of which is adjustable, and before starting the compressor, after operating the expansion valve in advance to a certain initial opening, the compressor is started to start the hot water supply operation. A control device for starting, the control device predicts the expansion valve target opening during the current hot water supply operation stabilization based on the expansion valve opening during the previous hot water supply operation stabilization,
After setting the intermediate opening between the target opening and the initial opening and starting the compressor, the opening of the expansion valve at the first operating speed from the initial opening to the intermediate opening. Controlling the opening of the expansion valve at a second operating speed smaller than the first operating speed until the target opening is reached after reaching the intermediate opening. . 5. The heat pump water heater according to claim 3, wherein the control device has a storage circuit for storing an expansion valve opening when the hot water supply operation is stable, and the storage circuit is provided for each operation. A heat pump type water heater characterized by updating an expansion valve opening when the hot water supply operation is stable. 6. A heat pump type water heater according to claim 1, wherein the target opening of said expansion valve is set to be larger as the outside air temperature becomes higher. . 7. The heat pump type water heater according to claim 1, wherein the target opening of the expansion valve is set to be larger as the temperature of the water supply becomes higher. . 8. The heat pump type water heater according to claim 1, wherein a temperature difference between the water flowing into the water heat exchanger and the refrigerant flowing out of the water heat exchanger is a target temperature difference. A heat pump type water heater characterized in that high pressure control in a cycle is performed so as to be ΔT. 9. The heat pump type water heater according to claim 1, wherein the refrigerant used in the heat pump cycle is CO ₂ .