JPH05340630A - Heat storage type air conditioner - Google Patents

Abstract

PURPOSE:To obtain an air conditioner having a heat reservoir which has a high efficiency and high load follow-up in a cycle having an ice storage tank of a heat storage type air conditioner. CONSTITUTION:A heat storage type air conditioner has a primary side refrigerating cycle and a secondary side refrigerating cycle connected through a heat reservoir STR. The reservoir has a primary side heat exchanger having a smooth inner heat transfer tube P1 and a secondary side heat exchanger having a heat transfer tube P2 in which thermal resistance is reduced inside a tube by increasing an inner heat transfer area thereof. The tube P2 of the secondary side exchanger in the reservoir is formed of an inner grooved tube or fins mounted therein thereby to reduce its thermal resistance inside the tube P2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner using air as a heat source, and has a heat storage function for utilizing nighttime electric power.
And a heat storage type air conditioner having a control function thereof.

[0002]

2. Description of the Related Art Various conventional heat storage type air conditioners have already been developed, for example, refrigeration / sixth type.
There is a heat storage type air conditioner as shown in P358 of Volume 2, No. 714 (April, 1987).

The basic technique is shown in FIG.
As shown in FIG. 1, the air-cooling heat pump 1 has a refrigeration cycle A in which a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, an outdoor expansion valve 5, a Freon-to-brine heat exchanger 6 are sequentially connected in an annular shape.
On the other hand, a freon-to-brine heat exchanger 6, a brine-to-water heat exchanger 7, a heat storage tank 8, and a brine pump 9 are sequentially connected in an annular shape to form a brine circulation cycle B.

On the load side, the brine-to-water heat exchanger 7, the heat storage tank 8, the cold / hot water pump 10, and the indoor unit 12 are sequentially connected in an annular shape to form a cold / hot water circulation cycle C.

In this heat storage type air conditioner, during the nighttime operation, the four-way valve 3 switches the ice making operation and the heat storing operation in the refrigeration cycle A, and during the ice making operation, the refrigerant flows in the direction of the solid line arrow in the figure to perform the cooling cycle. It is formed and stored as ice around the heat transfer tube in the heat storage tank 8 in the brine circulation cycle B via the Freon-to-brine heat exchanger 6.

Further, during the heat storage operation, the refrigerant flows in the direction of the broken line in the drawing to form a heating cycle, and heat is stored as hot water in the heat storage tank 8 in the brine circulation cycle B through the CFC-to-brine heat exchanger 6 as well. .. In this case, the brine to water heat exchanger 7 is not used.

On the other hand, during the daytime operation, the cold / hot water circulation cycle C is used.
In, the cold / hot water in the heat storage tank 8 is sent to the indoor unit 12 by the cold / hot water pump 10 to perform cooling / heating.

At this time, in order to increase the efficiency of the cold / hot water circulation cycle C, a refrigeration cycle A and a brine circulation cycle B
Is operated in the cooling or heating mode to precool or preheat the cold / hot water in the cold / hot water circulation cycle C via the brine-to-water heat exchanger 7.

As described above, the surplus power energy at night is converted into heat to store the heat and the power is used in the daytime to suppress the power peak at the time of high load in the daytime and level the power usage. Is possible.

[0010]

However, in the above-mentioned conventional example, since the two heat exchangers are provided between the heat source side and the load side, the heat exchange efficiency is poor, and cold / hot water is supplied to the load side. Since it is transported directly, if a water leakage accident occurs,
There was a drawback that water damage to OA equipment in offices with advanced A conversion was inevitable.

[0011] Therefore, an object of the present invention is to provide a heat storage type air conditioner having high efficiency and high safety.

[0012]

Means for Solving the Problems The technical means of the present invention for solving the above problems is to provide a heat storage tank in a heat storage type air conditioner comprising a primary side refrigeration cycle and a secondary side refrigeration cycle via a heat storage tank. Is composed of a primary-side heat exchange section composed of a smooth heat transfer tube in the tube and a secondary-side heat exchange section composed of a heat transfer tube in which the heat transfer area inside the tube is reduced to reduce the thermal resistance. It was done.

Here, the heat resistance inside the heat transfer tube can be reduced by installing the heat transfer tube of the secondary side heat exchange section in the heat storage tank with an inner grooved tube or with fins inside the tube. Become.

[0014]

The function of this technical means is as follows.

At night, the compressor, the four-way valve, the outdoor heat exchanger, the expansion valve, the switching valve, the primary side heat exchange section of the refrigerant-refrigerant heat exchanger, and the primary side heat exchange section in the heat storage tank are connected. In the communicating primary side refrigeration cycle, the switching valve is switched to a state in which the refrigerant-refrigerant heat exchanger is not used, the expansion valve is set to a predetermined opening degree, and inexpensive night-time power is used at night to store heat. Cool or store heat in water, which is a heat storage material, through a heat transfer tube in the tank.

On the other hand, during the daytime, the switching valve is switched in the primary side refrigeration cycle to operate without using the primary side heat exchange section of the heat storage tank, and in addition to the cold heat stored in the heat storage tank, refrigerant-refrigerant heat exchange is performed. The cooling / heating capacity in the primary side refrigeration cycle is exchanged with the refrigerant in the secondary side refrigeration cycle via the heat exchanger, and the refrigerant is transferred to the indoor heat exchanger by the refrigerant transfer pump to heat the indoor air and heat. The secondary refrigeration cycle to be replaced (cooling or heating) is operated.

That is, the heat storage material and the refrigerant stored as cold storage heat in the heat storage tank increase the heat transfer area inside the pipe in the heat storage tank to form a secondary heat transfer tube that reduces the thermal resistance inside the pipe. High-speed heat exchange is performed via the side heat exchange section, and the refrigerant is transferred to the indoor heat exchanger by the refrigerant transfer pump and exchanges heat with the indoor air (cooling or heating).

Therefore, heating or cooling operation can be performed in the daytime by the stored cold heat using the nighttime electric power, and not only the use of the electric power can be leveled but also the load responsiveness is improved.

Here, the thermal resistance of the primary side heat exchange section in the heat storage tank is also reduced by increasing the heat transfer area on the inner side of the heat transfer tube. The thermal resistance of the ice layer around the secondary heat exchange part is large, and considering the manufacturing cost, it is necessary to increase the heat transfer area inside the secondary side heat exchange part inside the heat storage tank. Since the effect of reducing the thermal resistance is small compared to the above, the primary-side heat exchange section in the heat storage tank is composed of an internal smooth tube.

With the above operation, not only cooling / heating operation can be performed by the cold storage heat using night power, but also the heat transfer area inside the heat storage tank is increased to reduce the thermal resistance inside the pipe. The secondary side heat exchange section including the heat transfer tube enables the cold heat to be taken out at high speed, and the load responsiveness is improved.

Further, the heat resistance inside the heat transfer tube can be reduced by disposing the heat transfer tube of the secondary side heat exchange section in the heat storage tank as a tube with a groove inside the tube or by providing fins inside the tube. Become.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the accompanying drawings, in which a tube with an internal groove is used as a heat transfer tube of a secondary heat exchange section in a heat storage tank. Are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a refrigeration cycle diagram of a heat storage type air conditioner according to an embodiment of the present invention. The heat storage type air conditioner of this embodiment includes an outdoor unit 11 and an indoor unit 12.

The outdoor unit 11 is a refrigerant comprising a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, an expansion valve 5, a three-way valve KV1, a primary side heat exchange section 14a and a secondary side heat exchange section 14b. It is composed of a heat exchanger for refrigerant HEX, a heat storage tank STR that is filled with water 16 as a heat storage material and is composed of a primary side heat exchange section 13a and a secondary side heat exchange section 13b, and a refrigerant transfer pump PM. ..

On the other hand, the indoor unit 12 comprises an indoor heat exchanger 17. 2 is a vertical cross-sectional view of the heat storage tank in FIG. 1, and FIG. 3 is a cross-sectional view of the secondary heat exchanger 13b in the heat storage tank STR. The primary side heat exchange section 13a and the secondary side heat exchange section 13b of the heat storage tank STR are shown in FIGS.
As shown in FIG. 5, the primary side heat exchange section 13a is composed of only the heat transfer tube P1, and the secondary side heat exchange section 13b is formed with the tube grooved tube P.
In the outdoor unit 11 configured by 2, the compressor 2, the four-way valve 3, the outdoor heat exchanger 4, and the expansion valve 5 are sequentially communicated with each other, and the refrigerant-to-refrigerant heat exchange is further performed via the three-way valve KV1. Primary side heat exchange section 14a of the vessel HEX and the heat storage tank ST
The primary side heat exchange part 13a in R is connected in parallel and the primary side refrigeration cycle is formed.

On the other hand, the secondary side heat exchange section 1 of the STR in the heat storage tank
3b and the secondary heat exchanger 1 of the refrigerant-to-refrigerant heat exchanger HEX
4b, the reversible refrigerant transport pump PM, and the indoor heat exchanger 17 are sequentially connected to each other to form a secondary refrigeration cycle.

Next, the operation of the structure of this embodiment will be described. Table 1 shows the open / closed states of the four-way valve 3, the expansion valve 5, and the three-way valve KV1 and the working state (evaporator or condenser) of each heat exchanger in each case in this embodiment. Hereinafter, description will be made with reference to (Table 1).

[0028]

[Table 1]

First, the nighttime ice making / heat storage operation (primary refrigeration cycle) will be described. In the primary side refrigeration cycle, the heat storage tank STR operates to operate the refrigerant-refrigerant heat exchanger HE.
The three-way valve KV1 is switched so that X does not act, and the refrigerant transfer pump PM in the secondary side refrigeration cycle is stopped. The operation of the primary side refrigeration cycle in this case will be described below.

Regarding the mode of the four-way valve 3, a cooling mode is used when the discharge side of the compressor 2 and the outdoor heat exchanger 4 and the suction side of the compressor 2 and the heat storage tank STR are connected to each other. A mode in which the discharge side of the compressor 2 communicates with the heat storage tank STR and the suction side of the compressor 2 communicates with the outdoor heat exchanger 4 is defined as a heating mode.

As for the three-way valve KV1, the first mode is set so that the heat storage tank STR and the expansion valve 5 are communicated with each other in the primary side refrigeration cycle, and the refrigerant-refrigerant heat exchanger HEX and the expansion valve 5 are communicated with each other. The setting is defined as the second mode.

Night-time ice making operation: The four-way valve 3 is set to the cooling mode, the expansion valve 5 is set to a predetermined opening, and the three-way valve KV1 is set to the first mode. The high-temperature and high-pressure refrigerant sent from the compressor 2 in this state is condensed in the outdoor heat exchanger 4 and is decompressed by the expansion valve 5 to be in a liquid or two-phase state, and the primary side heat exchange in the heat storage tank STR. After evaporating in the pipe of the portion 13a and absorbing heat from the water 16, the water is returned to the compressor 2.

At this time, the primary side heat exchange section 13a is connected to the heat transfer tube P.
Since there is only 1, the natural convection in the tank is not obstructed, and ice is relatively uniformly generated on the outer side of the entire heat transfer tube in the tank.

Night heat storage operation: The four-way valve 3 is in the heating mode, the expansion valve 5 is in a predetermined opening degree, and the three-way valve KV1 is in the first mode. The high-temperature and high-pressure refrigerant sent from the compressor 2 in this state is condensed in the pipe of the primary side heat exchange section 13a in the heat storage tank STR and radiates heat to the water 16, and then is decompressed by the expansion valve 5 to form liquid or liquid. It becomes a two-phase state, evaporates in the pipe of the outdoor heat exchanger 4, absorbs heat from the outside, and then returns to the compressor 2.

At this time, in the heat storage tank STR, as in the case of night heat storage operation, heat is stored as hot water without hindering natural convection in the tank.

Next, the daytime operation (secondary refrigeration cycle) will be described. In this case, the heat is stored in the heat storage tank STR (heat storage), but in the primary side refrigeration cycle, the three-way valve KV1 is used as the first mode to evaporate the secondary side heat exchange section 14a of the refrigerant-refrigerant heat exchanger HEX. It operates as a condenser (condenser).

At the same time, in the secondary side refrigeration cycle, the secondary side heat exchange section 14b of the refrigerant-to-refrigerant heat exchanger HEX is operated to operate.

In this state, the refrigerant in the secondary side refrigeration cycle is sent to the secondary side heat exchange section 13b in the heat storage tank STR by the refrigerant transfer pump PM, and the secondary side heat exchange section 13b is provided with a pipe groove. Since it is composed of the attached pipe P2, the heat transfer area inside the pipe can be made large, and the water 16 in the heat storage tank STR can be efficiently provided.
And heat is exchanged at high speed.

During cooling, the refrigerant flows as shown by the arrow a in FIG. 1, and the refrigerant cooled in the secondary heat exchange section 13b in the heat storage tank STR is further cooled by the refrigerant-refrigerant heat exchanger HEX 2.
It is sent to the secondary side heat exchange section 14b and cooled by heat exchange with the secondary side heat exchange section 14a of the refrigerant-refrigerant heat exchanger HEX in the primary side refrigeration cycle to become a liquid refrigerant.

After that, it is sent to the indoor heat exchanger 17 where it exchanges heat with the indoor air to cool the indoor air and
The refrigerant itself becomes a high-temperature gas refrigerant, which is 2 in the heat storage tank STR.
The operation of returning to the next-side heat exchange section 13b is repeated.

Further, during heating, the refrigerant flows as shown by an arrow b in FIG. 1, and the refrigerant heated in the secondary side heat exchange section 14b of the refrigerant-refrigerant heat exchanger HEX is further heated in the heat storage tank STR.
Water 16 sent to the secondary side heat exchange section 13b inside the heat storage tank
It is heated by heat exchange with and becomes a gas refrigerant.

After that, the reversible refrigerant transfer pump PM sends the heat to the indoor heat exchanger 17 where it exchanges heat with the indoor air to heat the indoor air, and the refrigerant itself becomes a low temperature liquid refrigerant and is reversible. The action of returning to the refrigerant transport pump PM is repeated.

In this way, even when the indoor load during the daytime is large, it is possible to cope with it, and the cooling / heating operation in the indoor unit is performed.

As described above, in the above embodiment, the heat storage tank ST
In the heat storage type air conditioner composed of the primary side refrigeration cycle and the secondary side refrigeration cycle via R, the heat storage tank STR has a primary side heat exchange section 13a constituted by an in-tube smooth heat transfer tube P1.
And the secondary side heat exchange section 1 including the pipe P2 with the groove in the pipe.
It is composed of 3b.

As a result, not only cooling (heating) operation can be performed by cold storage (heat storage) using nighttime power, power leveling can be achieved, but also secondary side heat exchange consisting of the pipe P1 with groove inside the heat storage tank STR. By the portion 13b, it becomes possible to take out cold storage (heat storage) at high speed, and load responsiveness is improved.

The case where the tube P2 with the internal groove is used as the heat transfer tube of the secondary side heat exchange section 13b in the heat storage tank has been described above, but FIG. 4 shows another embodiment of the present invention. Even when the fins F are installed in the heat transfer tube of the secondary side heat exchange section 13b inside, the same effect as the tube with groove P2 is provided.

[0047]

As described above, according to the present invention, in the heat storage type air conditioner including the primary side refrigeration cycle and the secondary side refrigeration cycle via the heat storage tank, the heat storage tank is constituted by an in-pipe smooth heat transfer tube. And a secondary-side heat exchange section that is composed of a heat-transfer tube that increases the heat transfer area inside the tube to reduce the thermal resistance inside the tube.

As a result, the cooling / heating operation can be performed by the cold storage heat using the nighttime electric power, and not only the use of electric power can be leveled, but also the heat transfer area in the heat storage tank is increased to increase the heat transfer area inside the pipe. The secondary side heat exchanging unit composed of a heat transfer tube whose resistance is reduced makes it possible to take out the cold stored heat at a high speed, and the load response is improved.

Also, the heat resistance inside the heat transfer tube can be reduced by installing the heat transfer tube of the secondary side heat exchange section in the heat storage tank with an inner groove tube or a fin inside the tube. Become.

[Brief description of drawings]

FIG. 1 is a refrigeration system diagram of a heat storage type air conditioner according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of the heat storage tank in FIG.

FIG. 3 is a cross-sectional view of the secondary heat exchanger in the heat storage tank in FIG.

FIG. 4 is a sectional view of a heat transfer tube of a secondary side heat exchanger in a heat storage tank according to another embodiment of the present invention.

FIG. 5 is a refrigeration system diagram of a heat pump type air conditioner showing a conventional example.

[Explanation of symbols]

 2 Compressor 3 Four-way valve 4 Outdoor heat exchanger 5 Expansion valve 13a Primary heat exchange part of heat storage tank 13b Secondary heat exchange part of heat storage tank 14a Primary heat exchange part of refrigerant-refrigerant heat exchanger 14b Refrigerant-to-refrigerant heat exchanger secondary side heat exchange section 17 Indoor side heat exchanger STR Heat storage tank F Fin P1 Primary side heat transfer tube (smooth tube heat transfer tube) P2 Secondary side heat transfer tube (tube with groove in tube) P3 2 Secondary heat transfer tube (tube with fin in tube) HEX Refrigerant-to-refrigerant heat exchanger PM Refrigerant transfer pump KV1 Three-way valve

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kozo Suzuki 1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Co., Inc. (72) Yoshihide Sugita 1-3-1, Uchisaiwai-cho, Chiyoda-ku, Tokyo Kyoden Co., Ltd.

Claims (3)

[Claims] 1. A compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and a switching valve are connected in series, and a primary side heat exchange section and a secondary side heat exchange section are provided. Refrigerant-to-refrigerant heat exchangers, primary side heat exchange parts of a heat storage tank having a primary side heat exchange part and a secondary side heat exchange part are arranged in parallel, and a refrigerant flow path is formed by the switching valve. A switchable primary side refrigeration cycle, a secondary side heat exchange section in the heat storage tank, a secondary side heat exchange section of a refrigerant-refrigerant heat exchanger, a refrigerant transfer pump, and an indoor side heat exchanger. A secondary side refrigeration cycle in which the heat storage tanks are connected to each other in an annular shape, and the heat storage tank has a primary side heat exchange section composed of a smooth heat transfer tube in the tube, and a heat transfer area inside the tube is increased to reduce thermal resistance inside the tube. A heat storage type air conditioner composed of a secondary side heat exchange section composed of the illustrated heat transfer tubes. 2. The heat storage type air conditioner according to claim 1, wherein in the secondary side heat exchange section of the heat storage tank, the heat transfer tube is a tube with a groove in the tube. 3. The heat storage type air conditioner according to claim 1, wherein the secondary side heat exchange section of the heat storage tank comprises a heat transfer tube having fins installed inside the tube.