JPH0257871A - Heat recovery type air conditioner - Google Patents

Abstract

PURPOSE:To maintain the capacity balance of room cooling and heating in response to variation in an operating state by connecting an auxiliary heat exchanger in parallel with a heat source side heat exchanger, connecting its gas line side to a discharge line to operate the auxiliary exchanger as only a condenser. CONSTITUTION:Three indoor units A-C are connected in parallel with one outdoor unit X. One auxiliary heat exchanger 9 is connected in parallel with an outdoor heat exchanger 3 in the unit X, and an auxiliary motor-driven expansion vale 10 as a second flowrate control mechanism for controlling flowrate of refrigerant to an auxiliary heat exchanger 9 is interposed at the side of its liquid line 11a. The gas tube of the exchanger 9 is always connected to the position to become a discharge line 11c to operate always only as a condenser with the exchanger 9 irrespective of the cycle of the exchanger 3. An air conditioner is operated in respective operation modes by a controller 52.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a heat recovery type air conditioner comprising a plurality of indoor units, each of which is individually connected to enable cooling/heating operation. Regarding reduction measures.

(Prior Art) Conventionally, as disclosed in, for example, Japanese Unexamined Patent Publication No. 62-252865, for an outdoor unit equipped with a compressor, a heat source side heat exchanger, and a flow control valve having a pressure reducing function, a user side A so-called heat recovery type air conditioner that consists of a refrigerant circuit in which multiple indoor units equipped with heat exchangers and pressure reduction mechanisms are connected in parallel, and is equipped with a connection switching mechanism that switches each heat exchanger between an evaporation cycle and a condensation cycle. In the device, two auxiliary heat exchangers are connected in parallel to the heat exchanger on the heat source side on the outdoor unit side, and one always functions as an evaporator and the other always functions as a condenser, and its capacity changes depending on the operating state. It is known to attempt to accurately maintain the balance of the heating and cooling capacity of the entire device by controlling the air conditioner.

(Problem to be Solved by the Invention) By using three auxiliary heat exchangers as in the above-mentioned conventional method, an imbalance occurs between the cooling capacity and the heating capacity when the device is in various operation modes. Impairing the feeling of air conditioning can be effectively prevented.

However, in that case, complicated control is required to properly function the three auxiliary heat exchangers and the heat source side heat exchanger, and the equipment becomes larger, resulting in increased space and manufacturing costs. There was a problem.

The present invention has been made in view of the above, and its purpose is to reduce the size of the device by providing a means for finely adjusting the capacity of the heat exchanger on the heat source side with a simple function. The goal is to realize simplified control and control, and to reduce manufacturing costs.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention includes a compressor (1), a heat source side heat exchanger (3), and a heat source side heat exchanger, as shown in FIG. For an outdoor unit (X) having a first flow rate control mechanism (4) having a refrigerant flow rate adjustment function and a pressure reduction function to a refrigerant flow rate control mechanism (3), a user-side heat exchanger (7) and the user-side heat exchanger Refrigerant piping (11) connects multiple indoor units (A) to (C) in parallel with a pressure reducing mechanism (6) for (7).
The refrigerant circuit (12) is connected to the refrigerant circuit (12), and the refrigerant is circulated in an evaporation cycle in which each of the heat exchangers (3) and (7) to (7) functions as an evaporator or in a condensation cycle in which the heat exchangers (7) function as an evaporator. so that each heat exchanger (3),
(7) - The gas line (11) of the refrigerant circuit (12) of (7)
b) is connected to the discharge line (11c) side and the suction line (
It is assumed that the heat recovery type air conditioner is equipped with a connection switching mechanism (51) that individually switches between the gas pipe side and the gas pipe side in parallel to the heat source side heat exchanger (3). 11c) and functions only as a condenser, and a second flow rate control mechanism (10) that adjusts the flow rate of refrigerant to the auxiliary heat exchanger (9). It is something.

(Function) With the above configuration, in the present invention, each indoor unit (A)
- (C) perform cooling and heating operations individually, thereby performing a heat recovery operation in which a part or all of each other's heat is recovered indoors. Then, the usage mode of the heat source side heat exchanger (3) and the auxiliary heat exchanger (9) is changed according to the value of the difference in size between the heating request and the cooling request on the indoor side, so that the heat balance of the entire device can be maintained. It will be planned.

In that case, the gas pipe side of the auxiliary heat exchanger (9) is always connected to the discharge line (11c) and functions only as a condenser, so there is no need for a separate switching valve, heat exchanger, etc., and the second flow rate control mechanism The capacity balance can be maintained in response to changes in operating conditions simply by adjusting the opening (10), making the device more compact and simplifying control. Therefore, manufacturing costs are reduced.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 shows the overall configuration of an air conditioner according to an embodiment of the present invention, in which two indoor units (A) to (C) are connected in parallel to two outdoor units (X). . The outdoor unit (X) has a variable capacity compressor (1) that is driven by an inverter (not shown) to vary the operating frequency.
and an outdoor heat exchanger (3) as a heat source side heat exchanger that functions as a condenser or an evaporator depending on the flow direction of the refrigerant;
During the condensation cycle in which the outdoor heat exchanger (3) functions as a condenser, the flow of refrigerant to the outdoor heat exchanger (3) occurs as shown by the solid line in the figure, and during the evaporation cycle in which the outdoor heat exchanger (3) functions as an evaporator, as shown in the broken line in the figure. a first four-way switching valve (2) that switches between an evaporation cycle and a condensation cycle; and a first four-way switching valve (2) that adjusts the flow rate of refrigerant to the outdoor heat exchanger (3), and the outdoor heat exchanger (3) functions as an evaporator. A first electric expansion valve (4) as a first flow rate control mechanism that sometimes functions as a refrigerant pressure reduction mechanism, a receiver (5) for storing liquid refrigerant, and a An accumulator (8) for separating liquid refrigerant is arranged.

In addition, each of the above-mentioned indoor units (A) to (C) has the same configuration, and an indoor heat exchanger (
7) and a second electric expansion valve (6) as a mechanism for reducing the pressure of the refrigerant to the indoor heat exchanger (7).

Each of the devices (1) to (8) in each of the units (X) and (A) to (C) is connected to a refrigerant pipe (11), respectively.
The heat exchangers (3), (
A refrigerant circuit (12) is configured to mutually exchange the heat applied in steps 7) to (7) via a refrigerant.

In addition, the gas line (11b) of the refrigerant circuit (12) is connected to the gas line (11b) for each of the indoor units (A) to (C) during the evaporation cycle in which the indoor heat exchangers (7) to (7) function as evaporators. As shown by the solid line, during the condensation cycle which functions as a condenser, the connection is switched as shown by the broken line in the figure, and the connection of each heat exchanger (7) to (7) with the gas line (1l b) is changed to that of the compressor (1). Second to fourth four-way switching valves (14) to (16) that are individually switched to the discharge line (11c) side and the suction line (11d) side are arranged. The first four-way switching valve (2) and the second to fourth four-way switching valves (14)
) to (16), each heat exchanger (3), (7) to (7
The gas lines (11
b) is connected to the discharge line (11c) side and the suction line (
A connection switching mechanism (51) is configured to individually switch to the 11d) side.

Here, as a feature of the present invention, the outdoor unit (X)
, the - auxiliary heat exchanger (9) is the outdoor heat exchanger (3)
Further, on the liquid line (11a) side, there is an auxiliary electric expansion valve (10) as a second flow rate control mechanism that controls the flow rate of refrigerant to the auxiliary heat exchanger (9).
) is provided. And the auxiliary heat exchanger (9)
The gas pipe side of is always connected to the discharge line (11c), so that the auxiliary heat exchanger (9) always functions only as a condenser, regardless of the cycle of the outdoor heat exchanger (3). We are trying not to do that.

Further, (52) is a controller for controlling the operation of the entire apparatus, and the air conditioner is operated in each operation mode by the controller (52).

In FIG. 1, (17) to (20) are the first to fourth four-way switching valves (2) and (14) to (16), respectively.
) heat exchangers (3), (7) to (7).

One connection port facing the connection port to the suction line (
11d) and the capillary (21a) interposed between
- (21c) are manual on-off valves installed at the outdoor unit (X) outlets of the liquid line (11a), suction line (11d), and discharge line (11c), respectively.

Next, each operation mode during operation of the air conditioner will be explained based on FIGS. 2 to 5.

Figure 2 shows a case where the three indoor units (A) to (C) are in a combined operation mode in which heating and cooling operations are performed individually, and indoor units (A) and (B) are both performing heating operation and the indoor unit ( The case where C) is performing cooling operation is taken as an example. At that time, the second electric expansion valves (6) (6) of the indoor units (A) and (B) are slightly open, and the first electric expansion valve (4) and the second electric expansion valve (4) of the indoor unit (C) are slightly open. The operation is performed while appropriately adjusting the opening degree of the electric expansion valve (6), and after the discharged refrigerant is condensed in the indoor heat exchangers (7), (7) of the indoor units (A), (B), Indoor heat exchanger (7) and outdoor heat exchanger (3) of other indoor unit (C)
It circulates in such a way that it evaporates (see the arrow in the figure). In other words, the indoor unit (A).

(B) and the indoor unit (C) perform cooling/heating return operation according to the air conditioning load, while the overall heating requirement is covered by heat exchange in the outdoor heat exchanger (3). ing. At that time, if the heating demand is greater than the cooling demand by a certain degree, a large evaporation capacity is required in the outdoor heat exchanger (3), so the auxiliary electric expansion valve (10)
is almost completely closed, and no refrigerant flows into the auxiliary heat exchanger (9) (hereinafter referred to as an outdoor heat exchanger independent evaporation cycle).

On the other hand, if the heating request is greater than the cooling request but the difference is small, as shown in FIG. 3, the auxiliary electric expansion valve (10) is opened in the same connection state as in FIG. After the discharged refrigerant is condensed not only in the indoor heat exchangers (6) and (6) of the indoor units (A) and (B) but also in the auxiliary heat exchanger (9), it is condensed in the indoor heat exchanger of the indoor unit (C). (7
) and the outdoor heat exchanger (3) to evaporate and circulate (
(See arrow in figure). That is, in order to reduce the evaporation capacity of the outdoor heat exchanger (3) in response to a decrease in heating demand, the opening degree of the first electric expansion valve (4) is controlled to be a little narrower, and the compressor (1)
While reducing the operating capacity of the refrigerant, a portion of the discharged refrigerant is released to the auxiliary heat exchanger (9) side to maintain an appropriate high pressure value (hereinafter referred to as a reverse cycle).

When the required cooling and heating capacities are very similar, for example, when each indoor unit (A) performs heating operation, indoor unit (B) performs cooling operation, and indoor unit (C) is stopped. In this case, the first electric expansion valve (4) is closed so that the outdoor heat exchanger (3) is not used. That is, as shown in FIG. 4, each four-way switching valve (2), (1
4) to (16) are switched to the solid line side in the figure, and the first electric expansion valve (4) and the second electric expansion valve (C) of the indoor unit (C) are switched to the solid line side in the figure.
6) is almost fully closed, the second electric expansion valve (6) of the indoor unit (A) and the auxiliary electric expansion valve (10) are slightly open, and the second electric expansion valve of the indoor unit (B) is almost fully closed. (6) is operated while appropriately adjusting the opening degree, and after the discharged refrigerant is condensed in the indoor heat exchanger (7) and auxiliary heat exchanger (9) of the indoor unit (A), It circulates in the indoor heat exchanger (7) of the indoor unit (B) so as to evaporate (see the arrow in the figure). In other words, if the difference in air conditioning load between the indoor units (A) and (B) is extremely small, the capacity of the indoor heat exchanger (3) is not used and the capacity of the auxiliary heat exchanger (9) is not used.
) is used to balance the capacity against the load (hereinafter referred to as the auxiliary heat exchanger independent condensation cycle).

When the cooling demand is large, for example in a single operation mode in which all indoor units (A) to (C) perform cooling operation, each four-way switching valve (2), as shown in FIG.
(14) to (16) are switched as shown by the solid lines in the figure, and each of the second electric expansion valves (6) to ( The operation is performed while appropriately adjusting the opening degree of 6), and after the discharged refrigerant is condensed in the outdoor heat exchanger (3) and the auxiliary heat exchanger (9), each indoor unit (A) to (C) indoor heat exchanger (7
) to (7) to circulate to evaporate (see arrows in the figure)
. In other words, when the capacity of the outdoor heat exchanger (3) is insufficient for the air conditioning load, the capacity is balanced with the auxiliary heat exchanger (9) (hereinafter referred to as the simultaneous condensation cycle). do).

Therefore, in the above embodiment, when the indoor air conditioning demand is large as the heating demand, the outdoor heat exchanger (3) is set to an independent evaporation cycle without using the auxiliary heat exchanger (9) on the indoor side. On the other hand, the capacity balance is maintained by using the auxiliary heat exchanger (9) as the indoor heating demand becomes smaller and shifts to the cooling demand side.

When the heating demand on the indoor units (A) to (B) side is larger than the cooling demand to some extent, the first The opening of the electric expansion valve (4) is controlled to reduce the operating capacity of the compressor (1), but at this time, the auxiliary heat exchanger ( By reversing 9) and using the auxiliary heat exchanger (9) as a condenser, a portion of the discharged refrigerant is released to the auxiliary heat exchanger (9) side to maintain an appropriate high pressure value. This is possible.

In addition, when the difference between heating demand and cooling demand is extremely small, the auxiliary heat exchanger (9) is used as an independent condensing cycle to perform fine capacity adjustment without using the outdoor heat exchanger (3). In order to minimize the capacity of the outdoor heat exchanger (3), the capacity of the compressor (1) must be controlled unreasonably and the first electric expansion valve (4)
) has the advantage that there is no need to control the opening degree.

Furthermore, when the indoor units (A) to (C) are operated in the combined mode, even if the magnitude relationship between the heating request and the cooling request is frequently reversed due to changes in the operating state, the above-mentioned figures 3 and 4 As shown in the figure, the capacity balance can be maintained according to changes in the opening degree of the first electric expansion valve (4) without changing the connection state of the connection switching mechanism (51). Deterioration in reliability due to frequent switching can be effectively prevented.

In that case, the gas pipe side of the auxiliary heat exchanger (9) is always connected to the discharge line (11c) and functions only as a condenser, so there is no need for a separate switching valve or two heat exchangers like in the past. First, the balance of capacity can be maintained in response to changes in operating conditions simply by adjusting the opening degree of the second flow rate control mechanism (10), making the device more compact and simplifying control. Therefore, it is possible to reduce manufacturing costs.

(Effects of the Invention) As explained above, according to the present invention, in a heat recovery type air conditioner, the auxiliary heat exchanger is connected in parallel to the heat exchanger on the heat source side, and the gas line side thereof is connected in parallel to the heat exchanger on the heat source side. Since the auxiliary heat exchanger is connected to the line and functions only as a condenser, it is possible to maintain the balance of heating and cooling capacity in response to changes in operating conditions with a compact device and simple control. , it is possible to reduce manufacturing costs.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and Fig. 1 shows its refrigerant system diagram, Figs. 2 to 5 show the operating status of the device in each operation mode, and Fig. 2 shows the outdoor heat during simultaneous cooling and heating operation. When the exchanger is in a single evaporation cycle, Fig. 3 shows when the outdoor heat exchanger and auxiliary heat exchanger are in a reverse cycle when cooling and heating are simultaneously operated, and when the 4th
The figure shows the refrigerant circulation when the auxiliary heat exchanger is in the single condensing cycle during simultaneous cooling and heating operation, and Figure 5 shows the refrigerant circulation when the outdoor heat exchanger and the auxiliary heat exchanger are in the same cycle during single cooling operation. be. (1) Compressor, (3) Outdoor heat exchanger (heat source side heat exchanger), (4) First electric expansion valve (first flow rate control mechanism), (6)・・Second electric expansion valve (pressure reducing mechanism)
, (7)...Indoor heat exchanger (user side heat exchanger), (9
)... Auxiliary heat exchanger, (10)... Auxiliary electric expansion valve (second flow rate control mechanism), (11)... Refrigerant piping, (1
l b)...Gas line, (11c)...Discharge line, (11d)...Suction line, (12)...Refrigerant circuit, (51)...Connection switching mechanism, (X)... ...Outdoor unit, (A) to (C)...Indoor unit. Figure Figure

Claims (1)

[Claims] (1) It has a compressor (1), a heat source side heat exchanger (3), and a first flow rate control mechanism (4) having a refrigerant flow rate adjustment function and a pressure reduction function to the heat source side heat exchanger (3). A plurality of indoor units (A) to (C) each having a user-side heat exchanger (7) and a pressure reduction mechanism (6) for the user-side heat exchanger (7) are connected to the outdoor unit (X) in parallel with the refrigerant. An evaporation cycle in which the heat exchangers (3) and (7) to (7) function as evaporators or a condensation cycle in which the heat exchangers (3) and (7) function as condensers, and each heat exchanger (3), (7) to (7) functions as an evaporator. Each heat exchanger (3), (7) to (
7) A heat recovery type air conditioner equipped with a connection switching mechanism (51) that individually switches the connection of the refrigerant circuit (12) to the gas line (11b) to the discharge line (11c) side and the suction line (11d) side. In the device, the heat source side heat exchanger (3)
An auxiliary heat exchanger (9) is connected in parallel to the discharge line (11c) on the gas pipe side and functions only as a condenser
) and a second flow rate control mechanism (10) that adjusts the flow rate of refrigerant to the auxiliary heat exchanger (9).