JP2989491B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system having two heat source side heat exchangers (air-cooled heat exchanger and water-cooled heat exchanger).

[0002]

2. Description of the Related Art A refrigeration system in which an air-cooled heat exchanger and a water-cooled heat exchanger are connected in parallel is disclosed in Japanese Patent Publication No.
There is JP-A-9-17776. In the refrigeration apparatus (air conditioner) disclosed in this publication, when the outside air temperature decreases during the heating operation, the refrigerant is switched from the air-cooled heat exchanger to the water-cooled heat exchanger and flows.

[0003] Thus, even if the outside air temperature decreases during the heating operation, a decrease in the heating capacity is suppressed as much as possible.

[0004]

As described above, when the outside air temperature decreases during the heating operation, the heat exchanger acting as the evaporator is switched from the air-cooled type to the water-cooled type. The fuel cost of a heater such as a boiler for supplying hot water to the heater rises sharply. In addition, when the water-cooled heat exchanger is operated, the air-cooled heat exchanger is not operated, so that the heat source at the time of heating depends only on the operation of the heater described above. I can't escape.

[0005] As a result, it is considered that the advantage of "low running cost of heat pump heating" utilizing an air heat source (air-cooled heat exchanger) cannot be utilized. INDUSTRIAL APPLICABILITY The present invention provides a refrigeration system that can sufficiently exhibit the advantage of low running cost using an air heat source while using a water heat source, and that suppresses a decrease in indoor temperature while performing defrosting of an air-cooled heat exchanger ( (Air conditioner).

[0006]

According to the first aspect of the present invention, there is provided the following:
Compressor and hot water are supplied and act as an evaporator.
From the water-cooled heat exchanger connected to the suction side of the compressor 1
And a first series circuit connected in parallel with the first series circuit.
When acting as a second compressor and evaporator.
2 air-cooled heat exchanger connected to the suction side of the compressor
An indoor unit having a second series circuit
An indoor unit equipped with a heat exchanger and a pressure reducer is connected
Of the water-cooled heat exchanger
And only the air-cooled heat exchanger is used as an evaporator
When operating, the refrigerant from the air-cooled heat exchanger is
A communication pipe for leading to the first compressor is provided.
And

[0007] The invention of claim 2 is the invention according to the first invention.
Operating the indoor heat exchanger as a condenser, and
During defrosting operation when the water-cooled heat exchanger acts as an evaporator
A part of the refrigerant discharged from the compressor is used for the air-cooled heat exchange.
A hot gas defrost pipe leading to the heat exchanger.
You.

[0008]

In the first invention, an air-cooled heat exchanger and a water-cooled heat exchanger are provided.
If the heat exchanger is acting as an evaporator,
Refrigerant from the heat exchanger and the air-cooled heat exchanger are respectively at the first pressure.
Guided to the compressor and the second compressor, only the air-cooled heat exchanger
When working, the refrigerant from the air-cooled heat exchanger
And a second compressor.

In the second aspect, the heat source of the water-cooled heat exchanger is empty.
Used as a defroster for cold heat exchangers and a heat source for indoor heating
It is.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes an air conditioner (refrigeration unit), which comprises an outdoor unit 2 and a plurality of indoor units 3;
a, 3b and inter-unit piping 4 connecting these units
It is composed of These indoor units 3a, 3b
Has a built-in pressure reducer (expansion valve) 5 and an indoor heat exchanger 6 capable of adjusting the valve opening. This indoor heat exchanger 6
Is also called a use side heat exchanger, and acts as a condenser during a heating operation and as an evaporator during a cooling operation.

The first and second compressors 71 and 72 are connected in parallel. The discharge pipe 8 is connected to the first connection port 10 of the four-way valve 9, and the suction pipe 11 is connected to the second connection of the four-way valve 9. Each is connected to the connection port 12. Reference numeral 13 denotes a heat source side heat exchanger, which generally acts as an evaporator during a heating operation and as a condenser during a cooling operation. The heat source-side heat exchanger 13 includes a first outdoor heat exchanger 14 serving as a water heat source and a second outdoor heat exchanger 15 serving as an air heat source. One end of the second outdoor heat exchanger 15 is connected to the third connection port 16 of the four-way valve 9.
The other end is connected to a liquid pipe 18 via a second on-off valve 17. 19 is a fan that blows air to the second outdoor heat exchanger 15. One end of the first outdoor heat exchanger 14 is connected to the suction pipe 20 of the first compressor 71, and the other end is connected to the liquid pipe 18 via the first on-off valve 21. Reference numeral 22 denotes a water pipe disposed in the first outdoor heat exchanger 14, which is heated water (about 15 ° C. or higher) heated by a boiler (not shown) or the like during a heating operation.
Is flowing. Reference numeral 23 denotes a check valve (open / close valve) provided in the first compressor, which is closed when the two outdoor heat exchangers 14 and 15 are simultaneously operated during the heating operation, and is used for the second outdoor heat exchange. When only the vessel 15 is operated, it is opened. This operation is one of the gist of the present invention, and will be described later in detail.

A hot gas defrosting tube 24 has an inlet end connected to the discharge tube 8 of the compressors 71 and 72 and an outlet end connected between the second outdoor heat exchanger 15 and the second on-off valve 17. . 25
Is a defrost valve provided in the hot gas defrost pipe 24, and is opened during the hot gas defrost operation. Reference numeral 26 denotes a controller for controlling the operation of the air-conditioning apparatus 1. The controller 26 performs a cooling operation, a heating operation, a hot gas defrosting operation, a reverse cycle defrosting operation, and the like. Are controlled as shown in FIG.

The various operations will be described. First, during the cooling operation, the open / closed state of the four-way valve 9 and various on-off valves is shown in FIG.
And the opening degree of the decompressor 5 of the indoor units 3a and 3b is adjusted according to the indoor load. As a result, the refrigerant discharged from the compressors 71 and 72 flows as indicated by broken arrows in FIG. Then, the second outdoor heat exchanger 15 functions as a condenser, and the indoor heat exchanger 6 functions as an evaporator, and performs a cooling operation. Here, the first outdoor heat exchanger 14
Stops the action.

The heating operation includes a heating operation using an air heat source using only the second outdoor heat exchanger 15 (hereinafter referred to as "high outdoor temperature heating"), a second outdoor heat exchanger 15 and the first outdoor heat exchanger. There is a heating operation using an air heat source and a water heat source in combination with the heat exchanger 14 (hereinafter referred to as “low outside air temperature heating”). This low outside air temperature heating is performed in a low outside air temperature where the high outside air temperature heating cannot provide a sufficient heating capacity, or in the indoor unit 3.
This is performed when the heating load increases due to an increase in the number of operating units a and 3b.

First, for the high outside air temperature heating, the four-way valve 9 is set to a solid line state in FIG. 1 and the opening and closing states of various on-off valves are controlled as shown in FIG. That is, the flow of the refrigerant is opposite to the flow of the refrigerant during the above-described cooling operation, and the indoor heat exchanger 6 acts as a condenser, and the second outdoor heat exchanger 15 acts as an evaporator to perform high outdoor air temperature heating. Do. On the other hand, the low outside air temperature heating is different from the above high outside air temperature heating in that the first on-off valve 21
Is increased in accordance with the situation where the outside air temperature is decreasing or the situation where the heating load is increasing. That is, the opening degree of the first on-off valve 21 is adjusted by a signal from the controller 26, whereby the refrigerant in the liquid pipe 18 is transferred to the first outdoor heat exchanger 15 and the second outdoor heat exchanger 14. Co-current. Then, the refrigerant subjected to the evaporating action in the second outdoor heat exchanger 15 is sucked into the second compressor 72 via the four-way valve 9. On the other hand, the refrigerant having undergone the evaporating action in the first outdoor heat exchanger 14 is sucked into the first compressor 71. Here, the second outdoor heat exchanger 15 is air-cooled, while the first outdoor heat exchanger 14 is water-cooled. Generally, the air-cooled type is a heat source with an outside air temperature of 0 ° C., and the water-cooled type is a heat source with a water temperature of about 15 ° C. Therefore, the pressure of the refrigerant flowing out of the first outdoor heat exchanger 14 is equal to the second outdoor heat exchanger 15. Higher than the pressure of the refrigerant flowing out of the pump. For this reason, in this low outdoor temperature heating, the check valve 23 is always “closed”, and the refrigerant flowing out of the first outdoor heat exchanger 14 and the refrigerant flowing out of the second outdoor heat exchanger 15 are separated. , Both compressors 71, 7
No mixing occurs on the suction side of No. 2 (see dash-dotted arrow). As described above, the refrigerant is heated by the water heat source using the first outdoor heat exchanger 14, and the possibility that the refrigerant temperature decreases in accordance with the decrease in the outside air temperature is reduced. As a result, the density of the refrigerant increases due to an increase in the temperature of the refrigerant flowing into the second outdoor heat exchanger 15, and as a result, the amount of the refrigerant flowing into the second outdoor heat exchanger 15 increases, and The lowering of the evaporation temperature of the refrigerant in the second outdoor heat exchanger 15 can be suppressed to a low level to prevent frost formation. As a result, stable operation can be performed even in low outside air.

As described above, when the flow of the refrigerant in the outdoor unit 2 during the cooling operation (dashed arrow) is compared with the flow of the refrigerant in the outdoor unit 2 during the low outdoor temperature heating operation (dashed line arrow), the cooling operation is performed. At the time, the refrigerant flows only through the second outdoor heat exchanger 15, and during the (low outdoor air temperature) heating operation, the first refrigerant flows through the first outdoor heat exchanger 15.
In addition, the refrigerant flows to the second outdoor heat exchangers 14 and 15. By flowing the refrigerant in this manner, the cooling operation is a so-called “air heat source system”, and the heating operation is a so-called “air heat source system + water heat source system” so that the heating capacity is larger than the cooling capacity. Therefore, it matches the climate of Japan where the heating capacity is more desirable than the cooling capacity.

Next, when the flow of the refrigerant in the outdoor unit 2 in the low outdoor air temperature heating operation (dashed line arrow) is compared with the flow of the refrigerant in the outdoor unit in the high outdoor air temperature heating (solid arrow), 2nd outdoor heat exchanger 1 during heating
The refrigerant having undergone the evaporating action in 5 flows into (comes into) the two compressors 71 and 72 in parallel. On the other hand, during low outdoor temperature heating, the refrigerant from the second outdoor heat exchanger 15 flows to the second compressor 72 and the refrigerant from the first outdoor heat exchanger 14 flows to the first compressor 71 as described above. Like that. In other words, a first series circuit in which the first compressor 71 and the first evaporator (first outdoor heat exchanger) 71 are connected in series, a second compressor 72 and a second evaporator (A second outdoor heat exchanger) 15 and a second series circuit connected in series,
When only one of the evaporators 15 is operated,
The refrigerant from the second evaporator 15 is divided into two compressors 71,
The suction pipe of the first compressor 71 provided with the check valve 23 serves as the communication pipe 24.

As described above, during the low outside air temperature heating operation,
Since the refrigerant flowing out of the outdoor heat exchangers 14 and 15 is sucked into the respective compressors 71 and 72 to prevent the refrigerant from being mixed, the first on-off valve 21 and the second on-off valve 17 are opened. The degree is determined by the compressors 71 and 72 and the outdoor heat exchangers 14 and 1 respectively.
The adjustment corresponding to the capacity of the above 5 can be performed so that each heat source can be used effectively.

When frost is generated in the second outdoor heat exchanger 15 by the two heating operations described above, hot gas defrost or reverse cycle defrost is performed to melt the generated frost. This hot gas defrosting is performed when the outside air temperature is relatively high or when the amount of generated frost is small. On the other hand, reverse cycle defrosting is performed when the outside air temperature is relatively low or when the amount of generated frost is large.

First, at the time of hot gas defrosting, it is basically the same as the low outside air temperature heating as shown by the solid line arrow in FIG. 3, and the difference is that the operation of the second compressor 72 is intermittent. (O
N-OFF), stopping the operation of the fan 19, and opening the defrost valve 25. A part of the refrigerant (hot gas refrigerant) discharged from the compressors 71 and 72 by the opening of the defrost valve 25 is supplied to the second outdoor heat exchanger 15.
To melt the frost generated in the second outdoor heat exchanger 15. During this hot gas defrosting operation,
The refrigerant discharged from the compressors 71 and 72 is supplied to the indoor heat exchanger 6.
In addition, since the water heat source of the first outdoor heat exchanger 14 is used as a heat source for defrosting and indoor heating, a reduction in defrosting time and a decrease in indoor temperature can be suppressed.

On the other hand, at the time of reverse cycle defrosting, only the first compressor 71 is operated as shown in FIG.
As a result, the refrigerant discharged from the first compressor 71 is as shown in FIG.
It flows like a dashed arrow. That is, the first compressor 7
The refrigerant discharged from 1 flows into the second outdoor heat exchanger 15 via the four-way valve 9 and performs defrosting here. Thereafter, the liquid is guided to the liquid pipe 18 via the second on-off valve 17, and is heated by the first outdoor heat exchanger 14 via the first on-off valve 21. And the first
Into the compressor 71. For this reason, the water heat source of the first outdoor heat exchanger 14 is used as a heat source for defrosting and indoor heating (to be described later). The decrease can be kept small. Here, it goes without saying that a part of the refrigerant in the liquid pipe 18 flows into the indoor heat exchanger via the decompressor 5, so that the heating operation is continued.

As described above, during the reverse cycle defrosting operation, the hot gas refrigerant (part of the hot gas refrigerant) is transferred from the second outdoor heat exchanger (air-cooled heat exchanger) 15 to the first outdoor heat exchanger (water-cooled heat exchanger). 14), the water heat source of the first outdoor heat exchanger 14 is used as a heat source for the defrosting and for heating, thereby shortening the defrosting time and controlling the room temperature during the defrosting operation. The decrease can be kept small.

In this embodiment, the first outdoor heat exchanger 14 employs a so-called "water-cooled heat exchanger" and the second outdoor heat exchanger 15 employs a so-called "air-cooled heat exchanger". The invention is not limited to these, but may be any heat exchanger using a heat source having a different temperature. That is, both of the two outdoor heat exchangers 13 may be “water-cooled heat exchangers”. In this case, the temperature of the water supplied from the boiler to the water-cooled heat exchanger is changed.

FIG. 4 shows a basic refrigerant circuit of the refrigeration apparatus of the first invention. In this figure, parts that are the same as the parts shown in FIG. That is, only the second outdoor heat exchanger 15 is used during the cooling operation (see the solid arrow), and the first and second outdoor heat exchangers 14 and 15 are used during the heating operation (see the broken arrow). Thus, the heating capacity can be made higher than the cooling capacity.

FIG. 5 shows a basic refrigerant circuit of the refrigeration apparatus of the second invention. In this figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. That is, when only one evaporator (outdoor heat exchanger) 15 is used, the refrigerant discharged from the evaporator 15 is supplied to the check valve 2.
By opening 3, the compressors are co-flowed to the two compressors 71 and 72. On the other hand, when the two evaporators 14 and 15 are used, the refrigerant discharged from each of the evaporators 14 and 15 by closing the check valve 23 is supplied to each of the compressors 71 and 72 connected in series with the evaporator. To flow separately.

FIG. 6 shows another embodiment of the present invention.
The difference from the embodiment of FIG. 1 is that the four-way valve is eliminated in the outdoor unit 2 and that the piping between the units is reduced from two to three.
It is a book. That is, the unit-to-unit pipe 41 is composed of a high-pressure gas pipe 42, a low-pressure gas pipe 43, and a liquid pipe 44, and the high-pressure gas pipe 42 is connected to the discharge pipe 8 of the compressors 71 and 72 and the second outdoor heat exchanger 15. It is connected to one end 45. The low-pressure gas pipe 43 is connected to the suction pipe 46 of the compressors 71 and 72 and the other end 47 of the second outdoor heat exchanger 15.
The liquid pipe 18 is in the same connection state as in the above-described embodiment.

The difference between the indoor units 3a and 3b (side) is that one end of the indoor heat exchanger 6 is branched, and the respective branch pipes 48 and 49 are connected to high-pressure gas pipes via high-pressure or low-pressure on-off valves 50 and 51, respectively. 42 and a low-pressure gas pipe 43. With such a configuration, the indoor units 3a and 3b can freely select a cooling operation or a heating operation. That is, when performing the cooling operation of the indoor unit 3a, the low-pressure on-off valve 51 is opened. As a result, the liquid refrigerant from the liquid pipe 18 flows into the indoor heat exchanger 6, and the indoor heat exchanger 6 performs an evaporating action, and the indoor unit 3a
Performs the cooling operation.

On the other hand, when heating the indoor unit 3b, the high-pressure on-off valve 48 is opened. As a result, the gas refrigerant from the high-pressure gas pipe 42 flows into the indoor heat exchanger 6, the indoor heat exchanger 6 performs a condensing action, and the indoor unit 3b performs a heating operation. Here, the operating state of the outdoor unit 2 is changed according to the cooling load and the heating load of each indoor unit described above. That is, when the cooling load is larger than the heating load, the cooling-main operation is performed. In this case, the refrigerant flows as indicated by the solid arrow in FIG.

When the heating load is larger than the cooling load, the operation becomes the heating main operation. In this case, the refrigerant flows as indicated by the solid line arrow in FIG. At this time, the second outdoor heat exchanger 15 functions as an evaporator. However, if the heat cannot be sufficiently pumped up by the outdoor heat exchanger 15, the on-off valve 21 is opened and the second outdoor heat exchanger 15 It flows into the heat exchanger 15. A part of the refrigerant is guided to the first outdoor heat exchanger 14, where it performs an evaporating action. As described above, when the outdoor unit 2 is in the cooling main operation, the first outdoor heat exchanger 1
4, the first outdoor heat exchanger 14 is used during the heating main operation.

[0030]

According to the first aspect of the present invention, when the outside air temperature is low,
Uses an air-cooled heat exchanger and a water-cooled heat exchanger simultaneously.
Can be heated in the indoor unit
In addition, at high outside temperatures, heating is performed using only air-cooled heat exchangers.
It can be carried out.

According to the second aspect of the present invention, the water-cooled heat exchanger
Heat source is the defrost of the air-cooled heat exchanger and the heat source for indoor heating
Air-cooled heat exchanger while heating the room
Defrosting operation can be performed.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus of the present invention.

FIG. 2 is an explanatory diagram showing an open / close state of various valves shown in FIG.

FIG. 3 is a refrigerant circuit diagram showing an operation state different from the operation state shown in FIG. 1;

FIG. 4 is a basic refrigerant circuit diagram of the present invention.

FIG. 5 is another basic refrigerant circuit diagram of the present invention.

FIG. 6 is a refrigerant circuit diagram showing another embodiment of the present invention.

FIG. 7 is a refrigerant circuit diagram showing an operation state different from the operation state shown in FIG. 6;

[Explanation of symbols]

5 Decompressor 6 User side (indoor side) heat exchanger 13 Heat source side heat exchanger 14 Outdoor heat exchanger (first evaporator: water-cooled heat exchanger) 15 Outdoor heat exchanger (second evaporator: air-cooled) Type heat exchanger) 24 connecting pipe

Claims (2)

(57) [Claims] An evaporator provided with a first compressor and hot water;
Connected to the suction side of the first compressor acting as
A first series circuit comprising a cold heat exchanger;
Connected in parallel with the circuit and acting as a second compressor and evaporator
Connected to the suction side of the second compressor when used
An outdoor having a second series circuit including an air-cooled heat exchanger
An indoor unit equipped with an indoor heat exchanger and a decompressor
In an air conditioner constituted by connecting knits, the operation of the water-cooled heat exchanger is stopped and the air-cooled heat exchanger is stopped.
When only the exchanger acts as an evaporator, the air cooling
The refrigerant from the heat exchanger to the suction side of the first compressor
An air conditioner characterized by providing a communication pipe for connection. 2. The indoor heat exchanger acting as a condenser.
And the water-cooled heat exchanger acts as an evaporator.
Part of the refrigerant discharged from the compressor during the frost operation is
The installation of a hot gas defrost pipe leading to an air-cooled heat exchanger
The air conditioner according to claim 1, characterized in that: