JP2003279177A - Water heater, ejector for vapor compression type refrigerating cycle, and vapor compression type refrigerating cycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot water supply machine using a heat pump unit suitable for continuous operation throughout a year. <P>SOLUTION: A needle valve 46 is displaced with using pressure balance between an operation chamber 47b which inert gas is filled in and a drive chamber 47a which high pressure side coolant flows into to control high pressure side coolant pressure roughly constant. Although temperature of supplied water during winter of low air temperature drops as compared with that during summer of high air temperature, it is not a problem in a practical use. Since it is not necessary to increase pressure tightness of high pressure side equipment such as a water coolant heat exchanger and compressor more than necessary level to meet requirement for summer of high air temperature, pressure tightness reliability of the hot water supply machine can be increased while reducing manufacturing cost of the hot water supply machine. Since restriction opening of a nozzle 41 is controlled by an actuator of a simple structure having inert gas filled in the operation chamber 47b, high pressure side coolant pressure can be control at low cost. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water heater, an ejector for a vapor compression refrigeration cycle, and a vapor compression refrigeration cycle.

[0002]

2. Description of the Related Art Considering the hot water supply load in the case of a water heater that heats hot water by a vapor compression heat pump unit, it is necessary in summer with high temperature and in winter with low temperature. Since the hot water temperature to be different is
The following problems occur when hot water is supplied at a temperature suitable for winter when the temperature is always low throughout the year.

That is, in the summer when the temperature is high, the temperature of the refrigerant flowing into the compressor rises and the entropy of the refrigerant drawn into the compressor becomes small, so that the hot water supply temperature equivalent to that in winter when the temperature is low is obtained. Requires the pressure of the high-pressure side refrigerant, that is, the discharge pressure of the compressor to be higher than in winter. Therefore, it is necessary to increase the pressure resistance of the high-pressure side device such as the water-refrigerant heat exchanger and the compressor.

In view of the above points, an object of the present invention is to provide a water heater using a heat pump unit suitable for continuous operation throughout the year.

[0005]

In order to achieve the above object, the present invention provides a compressor (1
0) has a high-pressure side heat exchanger (20) for cooling the high-temperature and high-pressure refrigerant, and an evaporator (30) for evaporating the low-temperature and low-pressure refrigerant that has been decompressed, so that the heat on the low-temperature side is high. It is a water heater which heats hot water with a vapor compression type heat pump unit (1) that is moved to the side, characterized in that the high pressure side refrigerant pressure of the heat pump unit (1) is controlled to be substantially constant. .

As described in the section "Problems to be solved by the invention", in summer when the temperature is high, the temperature of the refrigerant flowing into the compressor (10) rises and is sucked into the compressor (10). Since the entropy of the refrigerant becomes small, as is clear from the ph diagram shown in FIG. 2 to be described later, in order to obtain the hot water supply temperature equivalent to that in winter when the temperature is low, the refrigerant pressure on the high pressure side, that is, the compressor. The discharge pressure of (10) needs to be higher than in winter.

On the other hand, the hot water supply demand for the water heater, that is, the hot water supply temperature and the amount of hot water supply are not constant throughout the year, and the hot water supply demand in the summer when the temperature is high is smaller than that in the winter when the temperature is low.

Therefore, if the heat pump unit (1) is controlled so that the high-pressure side refrigerant pressure is substantially constant throughout the year as in the present invention, the hot water supply temperature is lower in the summer when the temperature is higher than in the winter when the temperature is low. However, there is no problem in practical use, and rather, it is not necessary to increase the pressure resistance of the high-pressure side heat exchanger (20), the compressor (10), and other high-pressure side equipment more than necessary according to the high summer temperature. It is possible to improve the pressure resistance reliability of the water heater while reducing the manufacturing cost of the water heater.

When the heat pump unit (1) is an ejector cycle as in the second aspect of the invention, the compressor (10) is compared with an expansion valve cycle such as an expansion valve that depressurizes the refrigerant in an isenthalpic manner. ) Power consumption can be reduced.

Further, as in the invention described in claim 3, the compressor (10) may compress the refrigerant to a pressure equal to or higher than the critical pressure of the refrigerant.

Further, as in the invention described in claim 4, carbon dioxide may be used as the refrigerant.

According to the fifth aspect of the present invention, the nozzle (4) for converting the pressure energy of the refrigerant flowing out of the high pressure side heat exchanger (20) into velocity energy to decompress and expand the refrigerant.
1), the refrigerant injected from the nozzle (41) and the evaporator (3)
0), the velocity energy is converted into pressure energy while being mixed with the refrigerant sucked from the pressure increasing portion (42, 43), and the nozzle (41) is displaced in the axial direction to move the nozzle (41). Of the needle valve (46) for adjusting the throttle opening of the drive chamber, the drive chamber (47a) filled with the refrigerant flowing into the nozzle (41) and the working chamber (47b) filled with the inert gas, and the drive chamber. A partition member (47) for displacing the needle valve (46) by displacing in accordance with the pressure difference between the pressure inside the (47a) and the pressure inside the working chamber (47b).
c, 47f, 47g).

As a result, it is possible to control the high-pressure side refrigerant pressure to be substantially constant at a low cost as compared with the case where an electric actuator is used.

The partition member may be composed of a thin film diaphragm (47c) as in the sixth aspect of the invention.

Further, as in the seventh aspect of the invention, the partition member may be constituted by a bellows-like bellows (47f).

Further, as in the eighth aspect of the present invention, a partitioning member for the piston (47g) which is slidably disposed via the sealing means (47h) may be constructed.

According to the ninth aspect of the invention, the elastic means (47) for exerting an elastic force for displacing the partition member (47c) toward the drive chamber (47a) acts on the partition member (47c).
j) may be provided.

According to the tenth aspect of the present invention, the compressor (10) for sucking and compressing the refrigerant, the high-pressure side heat exchanger (20) for cooling the refrigerant discharged from the compressor (10), and the refrigerant are evaporated. An evaporator (30) that absorbs heat by heat, and
And the ejector (40) according to any one of (1) to (4), the refrigerant is separated into a gas-phase refrigerant and a liquid-phase refrigerant, and the liquid-phase refrigerant is supplied to the evaporator (30). ), And an opening / closing valve (61) for opening / closing a defrosting circuit (60) that guides the refrigerant before being decompressed by the ejector (40) to the evaporator (30). It is characterized by

As a result, the defrosting operation can be performed by a simple means such as adding the defrosting circuit (60) and the opening / closing valve (61).

Incidentally, the reference numerals in the parentheses of the above-mentioned means are examples showing the correspondence with the concrete means described in the embodiments described later.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment)
As the heat pump unit 1, one using a vapor compression refrigeration cycle having an ejector type pressure reducing device,
FIG. 1 is a schematic view of a water heater according to this embodiment.

The compressor 10 suctions and compresses the refrigerant, and the water-refrigerant heat exchanger 20 heats the hot water by exchanging heat between the refrigerant discharged from the compressor 10 and the hot water. It is a high-pressure side heat exchanger that cools the refrigerant.

The compressor 10 is driven by an electric motor (not shown), and when the heating capacity of the water-refrigerant heat exchanger 20 is increased, the rotation speed of the compressor 10 is increased to increase the compressor 10. In order to increase the flow rate of the refrigerant discharged from the compressor while reducing the heating capacity, the compressor 10
To reduce the flow rate of the refrigerant discharged from the compressor 10.

By the way, in this embodiment, since carbon dioxide is used as the refrigerant, the refrigerant pressure in the water-refrigerant heat exchanger 20 becomes equal to or higher than the critical pressure of the refrigerant, and the refrigerant in the water-refrigerant heat exchanger 20 changes. The temperature distribution is such that the refrigerant temperature decreases from the refrigerant inlet side toward the refrigerant outlet side without condensing.

The evaporator 30 is a low-pressure heat exchanger that heats the outdoor air and the liquid-phase refrigerant to evaporate the liquid-phase refrigerant to evaporate the refrigerant and absorb heat from the outdoor air. The gas-phase refrigerant that has been expanded under reduced pressure and evaporated in the evaporator 30 is sucked, and the expansion energy is converted into pressure energy to raise the suction pressure of the compressor 10. The details of the ejector 40 will be described later.

Further, the gas-liquid separator 50 is a gas-liquid separating means for storing the refrigerant by separating the inflowing refrigerant into the gas-phase refrigerant and the liquid-phase refrigerant while the refrigerant flowing out from the ejector 40 flows in. The gas-phase refrigerant outlet of the liquid separator 50 is connected to the suction side of the compressor 10, and the liquid-phase refrigerant outlet is the evaporator 3
It is connected to the inflow side on the 0 side.

FIG. 2 is a ph diagram showing the macro operation of the ejector cycle as a whole. Since the macro operation is the same as that of a known ejector cycle, in this embodiment, the ejector cycle as a whole is operated. The description of the macro operation is omitted. By the way, the symbol shown by ● in FIG.
It shows the state of the refrigerant at the symbol position shown by ● shown in FIG.

Next, the structure of the ejector 40 will be described with reference to FIG.

The ejector 40 converts the pressure energy of the inflowing high pressure refrigerant into velocity energy to expand the refrigerant under reduced pressure, and the vapor phase refrigerant evaporated in the evaporator 30 by the high velocity refrigerant flow injected from the nozzle 41. While mixing the refrigerant injected from the nozzle 41 and the refrigerant sucked from the evaporator 30, while mixing the refrigerant flowing from the nozzle 41 with the refrigerant flow injected from the nozzle 41, the velocity energy is converted into the pressure energy. It comprises a diffuser 43 and the like for increasing the pressure.

In the mixing section 42, the nozzle 41
Since the sum of the momentum of the refrigerant flow injected from the and the momentum of the refrigerant flow sucked from the evaporator 30 to the ejector 40 is stored, the static pressure of the refrigerant also rises in the mixing section 42. On the other hand, in the diffuser 43, the dynamic pressure of the refrigerant is converted into the static pressure by gradually increasing the passage cross-sectional area, so in the ejector 40, the refrigerant pressure is increased by both the mixing section 42 and the diffuser 43. . Therefore, the mixing section 42 and the diffuser 43 are generically called a boosting section.

That is, in the ideal ejector 40, the refrigerant pressure increases so that the sum of momentums of two kinds of refrigerant flows is stored in the mixing section 42, and the refrigerant pressure is stored so that energy is stored in the diffuser 43. Is expected to increase.

By the way, around the nozzle 41, the body 4
4 is formed, and the vapor-phase refrigerant sucked from the evaporator 30 flows into the mixing section 42 via the suction chamber 45.

Further, the nozzle 41 is a divergent nozzle having a throat portion having the smallest passage area in the middle of the passage, and the throttle opening of the nozzle 41, that is, the throat opening, is the refrigerant pressure on the high pressure side. It is controlled by the needle valve 46 so as to be substantially constant. The needle valve 46 has a conical taper shape with a sharp tip, and is displaced in the axial direction by a mechanical actuator 47 in the nozzle 41.

Here, the mechanical actuator 47 is
Drive chamber 47a filled with high-pressure refrigerant flowing into the nozzle 41
And a working chamber 47b in which an inert gas is sealed, and a diaphragm as a partitioning member that displaces the needle valve 46 by displacing in accordance with the pressure difference between the pressure in the drive chamber 47a and the pressure in the working chamber 47b. 47c, diaphragm 4
7c, the diaphragm 47c is disposed on the drive chamber 47a side.
47d for restricting the maximum displacement of the drive chamber 47a, the drive chamber 47a and the working chamber 47b, and a stainless steel housing 47e forming an outer shell.

Incidentally, although nitrogen gas is used as the inert gas in this embodiment, an inert gas such as helium gas or argon gas may be used. Further, in the present embodiment, the diaphragm 47c and the needle valve 46 are made of stainless steel and are brazed together, but the present embodiment is not limited to this.

Next, the operation of the ejector 40 according to the present embodiment will be described focusing on the operation of the needle valve 46.

The drive chamber 47a and the working chamber 47b are partitioned with the diaphragm 47c interposed therebetween, and the needle valve 46 is constructed so as to be displaced integrally with the diaphragm 47c. At this time, the pressure in the drive chamber 47a is
A force such that the needle valve 46 is displaced in the direction in which the throttle opening of No. 1 is increased acts on the diaphragm 47c,
On the other hand, the pressure in the working chamber 47b causes the diaphragm 47c to exert a force such that the needle valve 46 is displaced in the direction in which the throttle opening of the nozzle 41 is reduced.

When the pressure in the driving chamber 47a rises and becomes larger than the pressure in the working chamber 47b, the diaphragm 47c and the needle valve 46 are moved so that the throttle opening of the nozzle 41 becomes large, as shown in FIG. Due to the displacement, the pressure in the drive chamber 47a, that is, the increase in the refrigerant pressure on the high-pressure side is suppressed, and the pressure becomes equal to the pressure in the working chamber 47b.

On the contrary, when the pressure in the drive chamber 47a decreases and becomes lower than the pressure in the working chamber 47b, the diaphragm 47c and the needle valve 46 are reduced so that the throttle opening of the nozzle 41 is reduced as shown in FIG. Is suppressed, the pressure in the drive chamber 47a, that is, the pressure drop of the refrigerant on the high pressure side is suppressed, and the pressure becomes equal to the pressure in the working chamber 47b.

Therefore, the throttle opening of the nozzle 41 is mechanically controlled so that the pressure of the refrigerant on the high pressure side and the pressure in the working chamber 47b become substantially the same.

At this time, the working chamber 47b is filled with an inert gas, and the filled gas does not condense, the displacement amount of the diaphragm 47c, and the drive chamber 4
Since the amount of change in the pressure of the enclosed gas with respect to the change in the temperature of the refrigerant flowing into 7a is very small, the pressure in the working chamber 47b is substantially constant within the practical range. Therefore, the mechanical actuator 47 adjusts the throttle opening of the nozzle 41 so that the refrigerant pressure on the high pressure side becomes substantially constant.

Next, the function and effect of this embodiment will be described.

As described in the section "Problems to be solved by the invention", in the summer when the temperature is high, the temperature of the refrigerant flowing into the compressor 10 rises and the entropy of the refrigerant drawn into the compressor 10 is increased. Therefore, as shown in FIG. 2, in order to obtain the hot water supply temperature equivalent to that in winter when the temperature is low, the pressure of the high-pressure side refrigerant, that is, the discharge pressure of the compressor 10 needs to be higher than that in winter.

On the other hand, the hot water supply demand for the water heater, that is, the hot water supply temperature and the amount of hot water supply are not constant throughout the year, and the hot water supply demand in the summer when the temperature is high is smaller than the hot water supply demand in the winter when the temperature is low.

Therefore, if the heat pump unit 1 is controlled so that the high-pressure side refrigerant pressure becomes substantially constant throughout the year as in the present embodiment, the hot water supply temperature in summer with high temperature is lower than that in winter with low temperature. However, there is no problem in practical use, and rather, it is not necessary to increase the pressure resistance of the high-pressure side devices such as the water-refrigerant heat exchanger 20 and the compressor 10 more than necessary according to the high summer temperature, so that the manufacturing cost of the water heater can be reduced. It is possible to improve the pressure resistance reliability of the water heater while achieving the above.

Further, in this embodiment, the actuator 47 having a simple structure in which the inert gas is filled in the working chamber 47b.
Since the throttle opening degree of the nozzle 41 is controlled by this, the high pressure side refrigerant pressure can be controlled at a lower cost than in the case where an electric actuator is used.

(Second Embodiment) In the first embodiment, the partition member is composed of the thin film diaphragm 47c, but in this embodiment, as shown in FIG. 5, the partition member is a bellows-shaped bellows 47f. It is configured by. In this embodiment, the inside of the bellows 47f becomes the working chamber 47b.

As a result, the displacement amount of the needle valve 46, that is, the stroke can be set larger than that in the first embodiment.

(Third Embodiment) In this embodiment, as shown in FIG. 6, the partition member is constituted by a piston 47g slidably arranged via a sealing means 47h such as an O-ring. .

As a result, the displacement amount of the needle valve 46, that is, the stroke can be set larger than in the first embodiment.

(Fourth Embodiment) In the present embodiment, as shown in FIG. 7, in addition to the inert gas, the partition member (piston 47g in this example) is provided with an elastic force for pressing it toward the drive chamber 47a. A coil spring 47j as an elastic means that acts on the member is provided in the working chamber 47b.

Although FIG. 7 shows the third embodiment to which the present embodiment is applied, the present embodiment is not limited to this, and the present embodiment is applied to the first or second embodiment. Forms can be applied.

Further, a coil spring 47j as elastic means
The location of is not limited to the inside of the working chamber 47b, and may be located outside the working chamber 47b, for example, outside the bellows 47f or on the drive chamber 47a side in the second embodiment.

(Fifth Embodiment) In this embodiment, the evaporator 3 is used.
The defrosting operation of 0 can be performed.

Specifically, as shown in FIG. 8, the high temperature / high pressure refrigerant before being depressurized by the ejector 40 is transferred to the evaporator 30.
Defrosting circuit 60 that leads to the refrigerant inlet side (gas-liquid separator 50 side) of
An electromagnetic on-off valve 61 for opening and closing is provided, and the high temperature / high pressure refrigerant guided by the defrosting circuit 60 is used for the gas-liquid separator 5
The check valve 62 is provided to prevent the check valve 62 from flowing into zero. The ejector 40 may be any one of the first to fourth embodiments.

Next, the characteristic operation of this embodiment and its effect will be described.

1. Normal operation (operation of heating hot water) The on-off valve 61 is closed and the compressor 10 is operated. Thereby, as described in the first to fourth embodiments, the heat pump unit 1 is operated in a state where the refrigerant pressure on the high pressure side is controlled to be substantially constant.

2. The compressor 10 is operated with the open / close valve 61 open during defrosting. As a result, the pressure of the refrigerant on the high pressure side decreases, so that the drive chamber 4
The pressure in 7a decreases, and as shown in FIG.
And the nozzle 41 is finally fully closed.

Therefore, the entire amount of the high temperature refrigerant discharged from the compressor 10 flows into the evaporator 30 via the defrosting circuit 60 and heats the evaporator 30 to remove the frost attached to the surface of the evaporator 30. Thaw.

Then, the refrigerant flowing out of the evaporator 30 passes through the mixing section 42 and the diffuser 43, and the gas-liquid separator 5
0, and is compressed again by the compressor 10.

As described above, in this embodiment, the defrosting operation can be performed by a simple means such as the addition of the defrosting circuit 60 and the opening / closing valve 61, and the increase in the manufacturing cost of the water heater can be suppressed. .

Although the high-temperature refrigerant is introduced into the defrosting circuit 60 from the outlet side of the water-refrigerant heat exchanger 20 in FIG. 8, the present embodiment is not limited to this, and the water-refrigerant heat exchanger is not limited to this. The high-temperature refrigerant may be introduced into the defrosting circuit 60 from the inlet side of 20 or in the middle of the water-refrigerant heat exchanger 20.

(Other Embodiments) In the above embodiment, carbon dioxide was used as the refrigerant, but the present invention is not limited to this, and for example, CFC may be used.
When the refrigerant is CFC, the water-refrigerant heat exchanger 2
The refrigerant pressure in 0 is equal to or lower than the critical pressure of the refrigerant, and the refrigerant is condensed in the water refrigerant heat exchanger 20.

In the above embodiment, the actuator 47 and the ejector 40 are made of stainless steel.
The present invention is not limited to this as long as the material has corrosion resistance and required strength.

In the above embodiment, the ejector cycle is used as the vapor compression type heat pump unit 1 for moving the heat on the low temperature side to the high temperature side. However, the present invention is not limited to this, and the expansion A valve cycle may be used.

In the above embodiment, the needle valve 46 is displaced by using the mechanical actuator 47. However, the pressure sensor detects the high pressure side refrigerant pressure, and the electric actuator operates the needle valve 46. It may be displaced.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a water heater according to a first embodiment of the present invention.

FIG. 2 is a ph diagram of an ejector cycle.

FIG. 3 is a schematic diagram of an ejector according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram of an ejector according to the first embodiment of the present invention.

FIG. 5 is a schematic diagram of an ejector according to a second embodiment of the present invention.

FIG. 6 is a schematic diagram of an ejector according to a third embodiment of the present invention.

FIG. 7 is a schematic diagram of an ejector according to a fourth embodiment of the present invention.

FIG. 8 is a schematic diagram of a water heater according to a fifth embodiment of the present invention.

[Explanation of symbols]

40 ... Ejector, 41 ... Nozzle, 42 ... Mixing section, 43
… Diffuser, 44… Body, 45… Suction chamber, 46…
Needle valve, 47 ... Actuator, 47a ... Drive chamber,
47b ... working chamber, 47c ... diaphragm, 47d ... stopper.

Claims (10)

[Claims] 1. A high-pressure heat exchanger (20) for cooling a high-temperature and high-pressure refrigerant compressed by a compressor (10), and an evaporator (30) for evaporating a decompressed low-temperature and low-pressure refrigerant. A water heater for heating hot water with a vapor compression type heat pump unit (1) that moves heat on the low temperature side to the high temperature side, and the pressure of the high-pressure side refrigerant of the heat pump unit (1) is substantially constant. Water heater characterized by being controlled as follows. 2. The heat pump unit (1) as a decompression means (40) decompresses and expands the refrigerant to suck the vapor phase refrigerant evaporated in the evaporator (30),
The water heater according to claim 1, wherein the water heater is a vapor compression refrigeration cycle having an ejector for converting expansion energy into pressure energy and increasing suction pressure of the compressor (10). 3. The compressor (10) compresses the refrigerant to a pressure equal to or higher than the critical pressure of the refrigerant.
Water heater described in. 4. The water heater according to claim 1, wherein carbon dioxide is used as the refrigerant. 5. A high pressure side heat exchanger (20) for cooling the high temperature and high pressure refrigerant compressed by the compressor (10), and an evaporator (30) for evaporating the decompressed low temperature and low pressure refrigerant. An ejector applied to a vapor compression refrigeration cycle for transferring heat on the low temperature side to the high temperature side, the pressure energy of the refrigerant flowing out from the high pressure side heat exchanger (20) being converted into velocity energy A nozzle (41) for decompressing and expanding the refrigerant, a refrigerant injected from the nozzle (41) and the evaporator (3).
(0) while mixing with the refrigerant sucked from the pressure increasing portion (42, 43) for converting velocity energy into pressure energy to increase the pressure of the refrigerant, the nozzle (41) is displaced in the axial direction, and the nozzle (41) is displaced. 41) a needle valve (46) for adjusting the throttle opening, a drive chamber (47a) filled with the refrigerant flowing into the nozzle (41), and a working chamber (47b) filled with an inert gas.
And a partition member (4) for displacing the needle valve (46) by displacing the needle valve (46) according to the pressure difference between the pressure in the drive chamber (47a) and the pressure in the working chamber (47b).
7c, 47f, 47g). 6. The ejector according to claim 5, wherein the partition member is a thin film diaphragm (47c). 7. The bellows (4) having a bellows shape is used as the partition member.
7f) is the ejector according to claim 5. 8. The partition member is a sealing means (47h).
The ejector according to claim 5, wherein the ejector is a piston (47g) slidably disposed through the ejector. 9. An elastic force for displacing the partition member (47c) toward the drive chamber (47a) is applied to the partition member (47).
Ejector according to any one of claims 5 to 8, characterized in that it comprises elastic means (47j) acting on c). 10. A compressor (10) for sucking and compressing a refrigerant.
A high pressure side heat exchanger (20) for cooling the refrigerant discharged from the compressor (10); an evaporator (30) for evaporating the refrigerant to absorb heat; The ejector (40) described, and the refrigerant is separated into a gas-phase refrigerant and a liquid-phase refrigerant, the liquid-phase refrigerant is supplied to the evaporator (30), and the gas-phase refrigerant is supplied to the compressor (10). A gas-liquid separator (50); and an on-off valve (61) for opening and closing a defrost circuit (60) that guides the refrigerant before being decompressed by the ejector (40) to the evaporator (30). Characteristic vapor compression refrigeration cycle.