JPH0522145B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention allows, for example, a plurality of indoor units to be connected to one outdoor unit so that cooling or heating operation can be selected individually, so that the outdoor unit can handle the total load. The present invention relates to an air conditioner that can perform accurate capacity control. (Prior art) Conventionally, a plurality of indoor units are connected in parallel to one outdoor unit, and at least one
When one indoor unit is in cooling operation, at least one remaining indoor unit is enabled for heating operation, and during this operation, the heat radiated for cooling can be directly used as a heat source for heating.
An air conditioner that can recover heat is disclosed in Japanese Patent Application Laid-Open No. 55-12372.
It is known from the publication no. In this known device, as schematically shown in FIG. 9, an outdoor unit A includes a compressor 1, a heat source side coil 2, a discharge gas on-off valve 3D, and an intake gas on-off valve 3.
S, a liquid side main pipe 5, a high pressure gas side main pipe 6, a low pressure gas side main pipe 7, and a heating expansion valve 30, while each indoor unit has a cooling expansion valve 8, a usage side coil 9, and an on-off valve 13A. The circuit configuration includes a high-pressure gas side branch pipe 11 having valves 14A to 13C interposed therein, and a low-pressure gas side branch pipe 12 having on-off valves 14A to 14C interposed, respectively. In this air conditioner, the on-off valves 14A and 14B are opened in the indoor units IA and IB which are intended for cooling, and the on-off valve 13C is opened in the indoor unit IC which is intended to be heated.
On the other hand, in the outdoor unit A, when the cooling load is large depending on the operating state, depending on whether the cooling load or the heating load is large, the heat source side coil 2 must act as a condenser, so the on-off valve 3D is On the other hand, when the heating load is large, the heat source side coil 2 must act as an evaporator, so it is necessary to open the on-off valve 3S. (Problem to be Solved by the Invention) However, the specific means for the above operation is unknown as it is not described in the above publication, but normally it is necessary to judge the cooling/heating signals of each indoor unit IA, IB, IC. Since there are
The connection wiring sent to each indoor unit IA, IB, IC
A rise in the cost of equipment was unavoidable due to the fact that it was required for each use. In view of the problems of the conventional air conditioner as described above, the present invention provides an indoor air conditioner by making it possible to accurately recognize the state of the overall air conditioning load on the outdoor unit side, that is, on the heat source side. Even if the cooling/heating operation is arbitrarily performed on the inside, that is, on the user side, the cooling/heating operation information from the user side is not required.
Automatically controls a balanced heat recovery operation based only on the information on whether or not the user is operating, and automatically controls the heat recovery operation in a multi-connection air conditioner while saving energy and achieving high operating economy. The main purpose is to realize the following. (Means for Solving the Problems) The present invention that achieves the above objects is described in the first embodiment.
As clearly shown in FIGS. 2 and 2, the compressor 1 is equipped with a capacity-controllable compressor 1 and a heat source coil 2, and one end of the heat source coil 2 is connected to a first switching valve device 3. The other end of the heat source side coil 2 is connected to the refrigerant flow rate control device 4 through a piping 3P that is connected to the discharge side and the suction side of the compressor 1 so as to be switchable.
is connected to the liquid side main pipe 5 through the compressor 1, and a high pressure gas side main pipe 6 is connected to the discharge side of the compressor 1, and a low pressure gas side main pipe 7 is connected to the suction side of the compressor 1. A plurality of series circuits are formed by connecting the use side coil 9 in series, and the cooling pressure reducer 8 side of each series circuit is connected to the liquid side main pipe 5 via the first auxiliary pipes 5A, 5A, 5A. At the same time, a second switching valve device connects the utilization side coil 9 side to the high pressure gas side main pipe 6 and the low pressure gas side main pipe 7 so as to be able to switch and communicate with the high pressure gas side main pipe 6 and the low pressure gas side main pipe 7. A capacity control device 19 that controls the capacity of the compressor 1 and a valve that controls the valve opening of the refrigerant flow rate control device 4 are connected via second auxiliary pipes 10P, 10P, and 10P having 10A, 10B, and 10C. Opening degree control device 20 and the first switching valve device 3
a control device 17 comprising a valve switching control device 21 for controlling valve switching, a condensing side detector S _H for detecting condensing pressure or condensing temperature, and an evaporating side detector S _L for detecting evaporating pressure or evaporating temperature. and, so that the condensing pressure or condensing temperature and the evaporating pressure or evaporating temperature each become a value within a predetermined range set as a control target,
A control command means 18 for operating the control device 17 in response to signals from the condensation side detector S _H and the evaporation side detector S _L is provided, and the use side coil 9...
This is an air conditioner in which each of these can be operated individually as a cooling evaporator or a heating condenser. (Function) The present invention is capable of controlling condensing pressure (temperature) and evaporating pressure (temperature) on the heat source side, for example on the outdoor unit A side.
If the condensing pressure (temperature) is within the set condition range, it is determined that the capacity is appropriate for the heating load, if it is lower than that, the capacity is insufficient, and if it is high, it is determined that the capacity is adequate for the heating load. On the other hand, if the evaporation pressure (temperature) is within the set condition range, it is determined that the capacity is appropriate for the cooling load, and if it is lower than that, it is determined that the capacity is excessive. In addition, if the value is high, the load status can be accurately understood by determining that the capacity is insufficient.
In response to the load at this time, the capacity of the compressor 1 is adjusted while the heat source side coil 2 acts as the current condenser or evaporator, and the opening degree of the refrigerant flow rate control valve 4 is adjusted. By controlling the heat exchange capacity of the heat source side coil 2 and further operating the first switching valve device 3 to switch the heat source side coil 2 to act as an evaporation switching valve device or a condensation switching valve device. Therefore, it is possible to automatically perform control according to the load, and as a result, efficient heat recovery air conditioning operation without causing disturbance can be realized. (Example 1) Hereinafter, a first example of the present invention will be described based on the accompanying drawings. In Figure 1, A is the outdoor unit, IA, IB,
In each indoor unit of IC, these indoor units IA,
IB and IC are connected to the outdoor unit A via a liquid side main pipe 5, a high pressure gas side main pipe 6 and a low pressure gas side main pipe 7. Outdoor unit A has a compressor 1 whose capacity can be controlled.
For example, a compressor 1 having a shaft-directly coupled electric motor driven by a capacity control device 19 (see FIG. 2) such as a frequency converter, a heat source side coil 2, and a refrigerant flow control device 4, for example, an electrically actuated refrigerant flow control device. valve 4 and
It includes a first switching valve device 3 and a liquid receiver 16. One end of the heat source side coil 2 is connected to the compressor 1 via a pipe 3P having a first switching valve device 3, and the first switching valve device 3 has two on-off valves 3D and 3S. The heat source side coil 2 is opened by opening the on-off valve 3D on the discharge side of the compressor 1.
On the other hand, by opening the on-off valve 3S, the suction side is alternately switched to the heat source side coil 2 so as to communicate therewith. On the other hand, the other end of the heat source side coil 2 is an expansion valve whose driving element is an electric device such as a pulse motor or an electromagnetic plunger, and whose opening degree can be adjusted according to the amount of input electricity. It is connected to the liquid side main pipe 5 via a refrigerant flow rate control device 4 (hereinafter simply abbreviated as a control valve) that easily adjusts the opening degree. Further, the high pressure gas side main pipe 6 is extended from the discharge side of the compressor 1, and the low pressure gas side main pipe 7 is extended and connected from the suction side. Note that 26 is a fan for the heat source side coil 2. Next, each of the indoor units IA to IC has a circuit configuration in which a cooling pressure reducer 8 and a use side coil 9 are connected in series, and a check valve 27 is connected in parallel to the pressure reducer 8. , the inflow side of the cooling pressure reducer 8 is connected to the liquid side main pipe 5 with first auxiliary pipes 5A, 5A,
5A, and one end that serves as an outlet during cooling operation of the user side coil 9 is connected to the high pressure gas side main pipe 6 and the low pressure gas side main pipe 7, and the on/off valves 13A to 13C on the high pressure gas side and the low pressure gas side. on-off valve 14
A second auxiliary pipe 1 equipped with a second switching valve device 10A, 10B, 10C connected to both gas side main pipes 6, 7 in a switching manner by a combination of A to 14C.
They are connected via 0P, 10P, and 10P. Note that 15 is a fan for the coil 9 on the user side. For air conditioners with the above circuit configuration, if you want to perform cooling operation with indoor units IA to IC,
Open the on-off valves 14A to 14C and open the on-off valves 13A to 1.
On the other hand, when heating operation is desired, the on-off valves 13A to 13C are opened and the on-off valves 14A to 14C are closed. On the other hand, in the outdoor unit A, the heat source side coil 2 must be operated as a condenser or an evaporator depending on whether the total load on the indoor side is a cooling load or a heating load, and in the former case, it must be opened and closed. It is sufficient to open the valve 3D and close the on-off valve 3S, or in the latter case, it is sufficient to open the on-off valve 3S and close the on-off valve 3D. The capacity of the compressor 1 is controlled by the capacity control device 19 as shown in FIG. The control device 17 is performed by a device 20, and these devices 19, 20 and a switching controller 21 that switches the valves of the first switching valve device 3 form the control device 17. As mentioned above, indoor units IA to IC can be switched to cooling or heating at will, and when cooling and heating are operated at the same time, the condensing capacity or evaporation capacity is adjusted to match the difference between the cooling load and the heating load. By allowing the heat source side coil 2 on the outdoor side to carry the capacity, heat recovery operation that efficiently utilizes exhaust heat becomes possible. In this case, the operation mode of the heat source side coil 2 is determined by the relationship between the cooling load qE and the heating load qC and the control valve 4.
FIG. 3 shows the relationship between the opening degree of the opening and closing state of the on-off valves 3D and 3S, and the opening/closing state of the on-off valves 3D and 3S. It means the direction in which it acts as a condenser. As is clear from FIG. 3, if you want to make the heat source side coil 2 act as a condenser and control its capacity, you can open the on-off valve 3D, close the on-off valve 3S, and adjust the opening degree of the control valve 4. Conversely, if you want to function as an evaporator and control the capacity, use the on-off valve 3S.
The opening degree of the control valve 4 may be adjusted by opening the on-off valve 3D and closing the on-off valve 3D. Furthermore, by using the capacity control of the compressor 1 in combination, it is possible to perform a refrigeration operation with no excess or deficiency commensurate with the air conditioning load, and to give control commands to the control device 17 that meet the purpose of this refrigeration operation. The control command means 18 will be explained below based on the drawings. The control command means 18 is shown in FIG. 2, and as described above, is composed of four circuits: a heating capacity judgment circuit 22, a cooling capacity judgment circuit 23, a capacity command control circuit 24, and a heat source side coil capacity control command circuit 25. The functions of each circuit are as explained below. The heating capacity determination circuit 22 has, for example, a pressure sensor SH as a condensing side detector that detects the pressure of the high pressure gas side main pipe 6 as an input signal element, and the high pressure detected by the sensor SH corresponds to the set conditions. If it is within the range, that is, within the pressure band region, it is assumed that there is no excess or deficiency in the heating capacity, and an appropriate heating capacity signal is issued.On the other hand, it is assumed that the capacity is insufficient, which is lower than the pressure band, and an insufficient heating capacity signal is issued. If the heating capacity is higher than that, it is assumed that there is sufficient capacity and an excess heating capacity signal is generated. Note that the sensor SH may detect the pressure in the liquid pipe 5, or may detect the condensing temperature instead of the pressure. In the case of this condensation temperature, it may not be possible to accurately detect it in a supercooled state, but it is possible to control it to some extent. The cooling capacity determination circuit 23 has, for example, a pressure sensor SL as an evaporation side detector that detects the pressure of the low pressure gas side main pipe 7 as an input signal element, and the low pressure detected by the sensor SL is within the range of the set conditions. If it is within the pressure band, the system determines that there is no excess or deficiency in the cooling capacity and issues an appropriate cooling capacity signal, while if it is lower than the pressure band, it issues an excess cooling capacity signal because there is room for capacity, and furthermore, If the cooling capacity is high, it is assumed that the cooling capacity is insufficient, and an insufficient cooling capacity signal is generated. Note that the evaporation temperature may be detected in place of the pressure detection by the sensor SL, but if the degree of superheating occurs, accurate detection may not be possible, but a certain degree of control is possible. Since three types of signals are emitted each from both judgment circuits 22 and 23, there are nine types of signal combinations. Therefore, the control operation mode is determined as shown in the table below, and the capacity control command circuit 24 and heat source By activating the side coil capacity control command circuit 25, smooth and stable air conditioning operation can be performed.

[Table] Shows the direction of use.
As is clear from the table above, in order to perform the nine types of control operations, the capacity control command circuit 24 must first ensure that one of the determination circuits 22 and 23 issues an appropriate heating (cooling) capacity signal, and that the other determines that the capacity is insufficient. The capacity control device 1 operates in two modes: a mode in which a cooling (heating) capacity signal is emitted, and a mode in which both sides issue an insufficient heating (cooling) capacity signal.
In addition, there is a mode in which one side emits an appropriate heating (cooling) capacity signal and the other side emits an excessive cooling (heating) capacity signal, and a mode in which one side emits an appropriate heating (cooling) capacity signal and the other side emits an excessive cooling (heating) capacity signal. In the mode in which the signal is being emitted, a capacity reduction command signal is issued to the capacity control device 19, and in other modes, a status quo maintenance command signal is issued.On the other hand, the heat source side coil capacity control command circuit 25 is In a mode in which an excess heating capacity signal and an appropriate cooling capacity signal or an insufficient cooling capacity signal are issued, and in a mode in which an appropriate heating capacity signal and an insufficient cooling capacity signal are issued, the heat source side coil 2 is made to act as a condenser. The coil 2 in the state
Since it is necessary to adjust the capacity of the valve, it is necessary to issue a switching command signal to the switching controller 21 to open the on-off valve 3D, and also send a switching command signal to the valve opening control device 20 to increase or decrease the valve opening. The mode in which the opening change command is issued, and the insufficient heating capacity signal and the appropriate cooling capacity signal or the excess cooling capacity signal are issued, and the mode in which the proper heating capacity signal and the excess cooling capacity signal are issued are the heat source Since it is necessary to adjust the capacity of the side coil 2 while it is operating as an evaporator, a switching command signal is issued to the switching controller 21 to open the on-off valve 3S, and the valve opening is adjusted. Control device 20
In other modes, a valve opening change command signal is issued to increase or decrease the valve opening, and in other modes, a status quo maintenance command signal is issued (which is the same as not issuing a signal). Note that both the above circuits 24 and 25 can easily perform calculations and send command signals by using a microcomputer, but in addition, a matrix calculation circuit with nine contact relays in three rows and three columns is basically used. This is also possible by forming an electromagnetic coil excitation circuit according to the wiring procedure and selectively activating each relay, and in either case, control is performed according to the operating mode shown in the flow diagram shown in Figure 4. It is something. Next, an outline of the operating mode of the air conditioner shown in FIG. 1 will be explained with reference to FIG. 4 as well. Taking as an example an operation mainly for heating in winter, when the power switch is turned on, the operation is started (a) and the initial settings are made at the same time (b). In this case, the valve opening control device 20 closes the control valve 4, and the switching controller 21 opens the on-off valve 3S and closes the on-off valve 3D. It is assumed that some of the indoor units installed in the computer room, for example, are set to cooling mode. After the start of operation, the heating capacity determination circuit 2 is activated every time a check signal is issued at a predetermined period such as every minute (c).
2 (D) and the cooling capacity determination circuit 23 (E). In Figure 4, Pc indicates high pressure, Pe indicates low pressure, and "suitable" indicates proper heating (cooling), and "high/
"Excessive" indicates that Pc is high and an excess heating capacity signal is being emitted, "High/Normal" means that Pe is high and an insufficient cooling capacity signal is being emitted, and "Low/Excessive" indicates that Pe is low and excessive cooling capacity is being emitted. Each indicates that a signal is being emitted. As mentioned above, based on the nine types of determination results, there is a signal to increase the capacity of the compressor 1 (F), a signal to decrease the capacity of the compressor 1 (G), a signal to cause the heat source side coil 2 to act as an evaporator, and a signal to cause the control valve 4 to act as an evaporator. Desired heat recovery type operation can be achieved by selectively transmitting a signal (H) that increases or decreases the valve opening degree, or a signal (R) that causes the control valve 4 to function as a condenser and increases or decreases the valve opening degree. becomes. In addition, the operation contents indicated by E and C in Fig. 4 are as follows.
This is an encoded flowchart of the flow shown in FIG. . In other words, if there is a change in the operating state from the initial setting state, and the cooling load > heating load has changed to cooling load < heating load, the flow will be as shown in Figure 5, and vice versa. When load<heating load becomes cooling load>heating load, the flow becomes as shown in FIG. 6. In other words, in FIG. 5, whether the current operation has been mainly heating with the on-off valve 3D closed or mainly cooling with the on-off valve 3D open is determined by whether the on-off valve 3D is open or not, and if it is open, it is mainly cooling. Therefore, the opening degree of the control valve 4 is reduced, and it is determined whether it is fully closed or not. If it is fully closed, the on-off valve 3D is closed, the on-off valve 3S is opened, and the main heating is switched. Further, if the on-off valve 3D is closed, the control valve 4
Increase the opening. In this way, the heating-based operation is achieved. Also, in FIG. 6, it is determined whether the current operation is mainly heating or cooling based on whether the on-off valve 3D is open or not. If it is open, it means that the operation is mainly cooling, so the control valve 4
Increase the opening. Also, if the on-off valve 3D is closed, the heating is mainly performed, so it is determined whether the control valve 4 is fully closed, and if it is not fully closed, the opening degree of the control valve 4 is decreased, and if it is fully closed, As a result, the on-off valve 3D is opened, and the on-off valve 3D is opened.
Close S to switch to cooling mode. In this way, when the high pressure Pc and the low pressure Pe reach values within the set condition range, a balanced heat recovery operating state is achieved, and a status quo maintenance command signal is issued (nu). (Embodiment 2) FIG. 7 shows a piping system according to another embodiment of the present invention, in which the first switching valve device 3 and the second switching valve devices 10A to 10C are each configured to have two opening/closing parts. The only difference is that a three-way switching valve is used instead, and it can perform exactly the same function as the previously described embodiment. (Embodiment 3) FIG. 8 shows yet another embodiment of the present invention, in which the heat source side coil 2 is divided into a plurality of coils 2A to 2C, and each coil 2A
~2C is connected to a refrigerant flow controller consisting of heating expansion valves 30A to 30C, check valves 31A to 31C, and on/off valves 32A to 32C, respectively, to switch the operation of only one, two at the same time, or three at the same time. It is possible to control the refrigerant flow rate as a whole by controlling the refrigerant flow rate, and the refrigerant flow rate controllers are collectively configured as a refrigerant flow rate control device 4, and the three-way switching valves 3A to 3C are collectively configured as a first switching valve device. It is composed of 3 parts. Note that 33 is an evaporation pressure regulating valve interposed in the middle of the low-pressure gas side main pipe 7, which always maintains the inflow side at a set pressure when there is a difference in evaporation pressure between the inflow side and the outflow side. It has a structure in which the flow resistance inside the valve can be changed by adjusting the valve opening degree, and the heat source side coils 2A to 2C are in an endothermic operation acting as an evaporator, and a part of the indoor unit is also in an endothermic operation. If the outside air temperature is low and the evaporation temperature on the outdoor side is -5°C when the evaporation pressure adjustment valve 33 is not installed, the evaporation temperature on the indoor side will also decrease, which is the worst case scenario. However, in this example, the regulating valve 33 operates to maintain the indoor evaporation temperature at a constant 5°C, thereby preventing frost formation and achieving stable operation, which has certain advantages. be. In the above embodiments of the present invention, the case where the heat source side is an outdoor unit and the user side is an indoor unit has been explained, but the present invention is not necessarily limited to this, and can be applied widely. Needless to say, it is applicable between the heat source side and a plurality of users. (Effects of the Invention) As described above, according to the present invention, even if the user side arbitrarily performs cooling and heating operations according to the load, the overall load on the heat source side is reduced to the heating load due to the above configuration. It is possible to accurately determine whether the cooling load is larger than or smaller than the cooling load, or whether it is balanced, and automatically cause the heat source side coil 2 to act as an evaporator or condenser, or to make it inactive. In addition, it becomes possible to appropriately control the operation of the compressor 1, and therefore, heat recovery operation can be easily and reliably performed in a multi-connection air conditioner, and energy saving performance is dramatically increased. In addition, the present invention enables each of the plurality of use-side coils 9 to individually operate as a cooling evaporator or a heating condenser, and also allows operation mode to be selected from the refrigerant state of condensing pressure (temperature) and evaporation pressure (temperature). By selecting the appropriate compression capacity for each mode and controlling the heat exchange capacity of the heat source side coil, fine-grained operation is possible, eliminating hunting phenomena and excess or deficiency in capacity, resulting in smooth and stable operation. air conditioning operation is achieved.

[Brief explanation of the drawing]

FIG. 1 is a piping system diagram according to an embodiment of the present invention,
FIG. 2 is a block diagram of the same control device and control command means, and FIG. 3 is a diagram explaining the principle of the present invention.
Figures 4 to 6 are flow diagrams showing the operating mode of the present invention, Figures 7 and 8 are piping system diagrams according to each embodiment of the present invention, and Figure 9 is a piping system diagram of a conventional device. be. A... Outdoor unit, IA, IB, IC... Indoor unit, 1... Compressor, 2... Heat source side coil, 3... First switching valve device, 4... Refrigerant flow rate control device, 5... ...Liquid side main pipe, 6...High pressure gas side main pipe,
7...Low pressure gas side main pipe, 8...Air conditioning pressure reducer, 9
...Using side coil, 10A, 10B, 10C...
Second switching valve device, 17...Control device, 18...Control command means, 19...Capacity control device, 20...Valve opening control device, 21...Switching control device.

Claims (1)

[Claims] 1 Compressor 1 and heat source side coil 2 that can control capacity
and one end of the heat source side coil 2,
It is connected to the discharge side and the suction side of the compressor 1 through a piping 3P having a first switching valve device 3 so as to be able to switch and communicate with each other, and the other end of the heat source side coil 2 is connected through a refrigerant flow rate control device 4. is connected to the liquid side main pipe 5, and a high pressure gas side main pipe 6 is connected to the discharge side of the compressor 1.
is configured by connecting the low-pressure gas side main pipe 7 to the suction side, while forming a plurality of series circuits in which the cooling pressure reducer 8 and the usage side coil 9 are connected in series,
The cooling pressure reducer 8 side of each series circuit is connected to the liquid side main pipe 5 via the first auxiliary pipes 5A, 5A, 5A, and the usage side coil 9 side is connected to the high pressure gas side main pipe 6 and the low pressure Second switching valve devices 10A, 10B, which are connected to the gas side main pipe 7, and the high pressure Gaga side main pipe 6 and the low pressure gas side main pipe 7 so as to be able to switch and communicate with each other.
Second auxiliary pipe 10P, 10P, 10P with 10C
A capacity control device 19 that controls the capacity of the compressor 1, a valve opening degree control device 20 that controls the valve opening degree of the refrigerant flow rate control device 4, and a valve switching device of the first switching valve device 3, which are connected via Valve switching controller 21 that controls
a condensing side detector S _H for detecting condensing pressure or condensing temperature; an evaporating side detector S _L for detecting evaporating pressure or evaporating temperature; control command means for operating the control device 17 in response to signals from the condensation side detector S _H and the evaporation side detector S _L so that the evaporation temperature falls within a predetermined range set as a control target; 18, so that each of the user-side coils 9 can be individually operated as a cooling evaporator or a heating condenser.