JPH0233937B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an air conditioning system, and more specifically, a common outdoor unit is provided with a compressor corresponding to a plurality of indoor units, and The present invention relates to an air conditioning system in which at least one of a heat exchange fan and a heat exchange fin is shared.

<Conventional technology> Conventionally, air conditioning systems have been provided in which multiple indoor units are connected to a common outdoor unit, and it has been possible to reduce the size and cost of the outdoor units in such air conditioning systems. In order to achieve this, a configuration is adopted in which at least one of a heat exchange fan and a heat exchange fin is shared.

In the air conditioning system configured as described above, the heating operation performance state and the state in which defrosting operation should be started are detected for each system corresponding to each indoor unit, and the defrosting operation in any system is detected. The defrosting operation is started when the state in which the operation should start is detected and the state in which the heating operation is being performed in all systems is detected, and the defrosting operation is started based on the operation duration, temperature rise, or pressure rise. After the defrosting operation is ended, a certain defrosting prohibition time is set in all systems until the next defrosting operation can be started.

Therefore, it is possible to detect that the system corresponding to any indoor unit has entered a state in which defrosting operation should be performed, and also to detect that the system corresponding to all indoor units has entered a state in which heating operation should be performed. In this case, the defrosting operation is started on the condition that the defrosting prohibition time in the relevant system has elapsed, and after the defrosting operation is finished, the defrosting prohibition time can be reset to the set time again.

<Problems to be Solved by the Invention> In the air conditioning system with the above configuration, only the systems corresponding to some indoor units are in heating operation due to the temperature conditions in the room where each indoor unit is installed. However, a situation may occur in which systems corresponding to other indoor units are not performing heating operation. In this case, frost forms intensively on the heat exchange fins corresponding to the system that is performing heating operation, and when the amount of frost formation exceeds a predetermined amount, it becomes necessary to perform defrosting operation. However, if other systems are not performing heating operation, defrosting operation is disabled to prevent the temperature in the room that is not performing heating operation from dropping. There is. Therefore, between the time when the entire system enters the heating operation state and the time when the defrosting operation actually starts, an amount of frost that cannot be removed by a single defrosting operation is generated. There is an inconvenience.

Furthermore, after detecting frost on the heat exchange fins for any system and performing defrosting operation, the defrost prohibition time (for example, 35 minutes) is uniformly set for all systems. Therefore, it is considered that a considerable amount of frost has been generated on the heat exchange fins on which the amount of frost required for defrosting operation has not been generated at the time when the defrosting operation of other systems is completed. Therefore, a large amount of frost is generated until the defrosting prohibition time elapses, and depending on the conditions for starting the next defrosting operation,
The problem is that the frost will not be completely removed.

<Purpose of the Invention> This invention has been made in view of the above-mentioned problems, and an object of the present invention is to reliably prevent the formation of more frost than can be removed on heat exchange fins corresponding to each system. The aim is to provide an air conditioning system that can.

<Means for Solving the Problems> In order to achieve the above object, the air conditioning system of the present invention includes a common outdoor unit provided with a compressor corresponding to a plurality of indoor units, and a heat exchanger. In an air conditioning system in which at least one of a replacement fan and a heat exchange fin is shared, a heating operation state detection means for detecting that each indoor unit is performing heating operation, and a heating operation state detection means for detecting that each indoor unit is performing heating operation, and A frost formation detection means for detecting frost formation on the replacement fins, an output signal from a heating operation state detection means indicating that only one of the indoor units is performing heating operation, and an output signal from the heating operation state detection means indicating that only one of the indoor units is performing heating operation. a defrosting control means that receives an output signal from a frost detection means indicating that frost has formed on the heat exchange fins of a system in which the heating operation is being performed, and causes the defrosting operation to be performed only in the system that is performing heating operation; The timer means sets the defrosting operation prohibition time for each system after the operation is completed, and the defrosting operation prohibition time of the timer means corresponding to the system in which the defrosting operation is performed is set to a relatively long predetermined time, and the defrosting operation is stopped. The invention also includes timer setting means for setting the defrosting operation prohibition time of the timer means corresponding to the system in which the defrosting operation is not performed to a relatively short predetermined time.

<Function> With the air conditioning system configured as described above, the common outdoor unit drives the necessary indoor units based on the temperature conditions in each room, and the heating operation status is detected while the heating operation is being performed. The means detects the indoor units performing heating operation, and the frost detection means detects that frost has formed on the heat exchange fins corresponding to the compressors connected to each indoor unit.

Then, the heating operation state detection means detects that only one of the indoor units is performing heating operation, and the frost formation detection means detects that the heat exchange fin corresponding to the system performing heating operation is detected. When it is detected that frost has formed more than the specified amount,
The defrosting control means causes the defrosting operation to be performed only on the system that was performing the above-mentioned heating operation, and after the defrosting is completed, the timer setting means sets the timer corresponding to all the systems that have performed the defrosting operation. A relatively long defrosting operation prohibition time can be set in the means, and a relatively short defrosting operation prohibition time can be set in the timer means corresponding to other systems.

In addition, when all the indoor units are in heating operation, if the frost detection means detects that a predetermined amount or more of frost has formed on the heat exchange fins corresponding to any system, the frost removal will be performed. The frost control means causes all the systems to perform defrosting operation, and after the defrosting is completed, the timer setting means allows a relatively long defrosting operation prohibition time to be set in the timer means corresponding to all the systems.

<Examples> Hereinafter, examples will be described in detail with reference to the accompanying drawings showing examples.

FIG. 3 is a schematic diagram showing an air conditioning system in which two indoor units 2 are connected to one outdoor unit 1. The outdoor unit 1 has a compressor 3 connected to each indoor unit 2. and a heat exchange fin 4 attached to a predetermined position of the refrigerant pipe through which the refrigerant sent out by each compressor 3 flows.
A heat exchange fan 5 is provided to supply cooling air to the heat exchange fin 4, and furthermore,
The heat exchange fin 4 and the heat exchange fan 5
is commonly attached to both refrigerant pipes. A thermistor 6 is attached to the heat exchange fin 4 at a predetermined position corresponding to each refrigerant pipe.

FIG. 2 is a block diagram showing the electrical configuration of the air conditioning system, in which a microcomputer 8 for the outdoor unit and a microcomputer 7 for the indoor unit are connected via a transmission control section 10. And thermistor 11 for detecting outside temperature
and the output signal from the thermistor 6 for detecting the outdoor coil temperature of each system are supplied to the microcomputer 8 via an A/D converter and an I/O port (not shown), and The output signals from the pressure switches 12 for high pressure control of each system are supplied to the microcomputer 8 through an I/O port (not shown), and the control signals from the microcomputer 8 are
It is supplied to the heat exchange fan 5, the four-way valve 14 of each of the above-mentioned systems, and the compressor 3 of each of the above-mentioned systems via an I/O and a driver (not shown).

Further, a control signal from the temperature setting device 15 and a control signal from the operation input device 16 are supplied to the microcomputer 7 via an I/O port (not shown), and a control signal from the thermistor 17 for suction temperature detection is supplied to the microcomputer 7 via an I/O port (not shown). The output signal and the output signal from the thermistor 18 for indoor coil temperature detection are supplied to the microcomputer 7 via an A/D converter (not shown) and an I/O port, and are further controlled by the microcomputer 7. A signal is supplied to the blower fan 19 via an I/O port (not shown) and a driver.

Next, the operation of the air conditioning system will be explained with reference to FIG.

In step 1, it is determined whether or not an operation start command has been issued, and if no operation start command has been issued, operation is directly stopped. If the operation start command has been issued, it is determined in step whether or not heating operation has been selected, and if heating operation has not been selected, cooling operation is performed in step. On the other hand, if heating operation is selected, a relatively long first defrosting operation prohibition time t1 (for example, 35 minutes) is set in timers T1 and T2 built in the microcomputer 8 in step, and It is determined whether or not T1 and T2 have timed up, and if neither has timed up, the step is determined again. Furthermore, if timer T1 has timed up, in step it is determined whether or not the system on the side of timer T1 (hereinafter referred to as system 1) is in a state where defrosting operation should be performed, If it is determined that it is necessary to perform
In step, it is determined whether the heating operation control thermostat of the indoor unit on the side of system 2 is ON.

Conversely, if it is determined in the above step that system 1 is not in a state where defrosting operation should be performed, then in step 1, it is determined whether or not timer T2 has timed up, and the system on the side of timer T2 (hereinafter referred to as system 2). It is determined whether or not the system is in a state where defrosting operation should be performed, and if both are determined as YES, it is determined in step whether or not the heating operation control thermostat of the indoor unit on the side of system 1 is ON. do. Conversely, if the determination is NO in any of the steps, the determination in the above step is performed.

If it is determined in step that timer T2 has timed up, it is determined in step whether or not system 2 is in a state where defrosting operation should be performed, and it is determined whether system 2 is in a state in which defrosting operation should be performed. If it is determined that this is the case, in step it is determined whether or not the heating operation control thermostat of the indoor unit on the side of system 1 is ON.

Conversely, if it is determined in the above step that system 2 is not in a state where defrosting operation should be performed, then in step 1 it is determined whether or not timer T1 has timed up, and whether system 1 is in a state where defrosting operation should be performed. If both are determined as YES, it is determined in step whether or not the heating operation control thermostat of the indoor unit on the side of system 2 is ON. Conversely, if the determination is NO in any of the steps, the determination in the above step is performed.

() In the above step, it is determined that the heating operation control thermostat of the indoor unit on the side of system 2 is OFF.In this case, in step 1, the defrosting operation of system 1 is started, and in step It is determined whether the heating operation control thermostat of the indoor unit is ON or not, and whether or not frosting of the system 1 has ended. If it is determined in the step that defrosting has not been completed, the process in the step is performed again, and if it is determined in the step that the heating operation control thermostat is ON, the above step is executed. Processing (described later) in the case where it is determined that the heating operation control thermostat is ON is performed.

If it is determined in step that defrosting has ended, a first defrosting operation prohibition time t1 is set in timer T1, and a relatively short second defrosting operation is set in timer T2.
After setting the defrosting operation prohibition time t2 (for example, 10 minutes) and waiting until the timer T2 times up in step, it is determined in step whether or not system 2 is in a state where defrosting operation should be performed, and the defrosting operation is performed. When it is determined that the state is such that frost operation should be performed, the process (described later) that would be carried out when it is determined that the heating operation control thermostat is ON in any of the above steps is performed. Furthermore, if it is determined in step that system 2 is not in a state where defrosting operation should be performed, it is determined in step whether or not timer T1 has timed up, and if it has timed up, the determination in the above step is performed. , if the time has not expired, the above step is determined.

() If it is determined that the heating operation control thermometer of the indoor unit is ON in any of the above steps (when the heating operation control thermometers of both systems are ON), in this case, both systems are The defrosting operation of the system is started, and in step it is determined whether the defrosting operation of the system 2 has ended.

If it is determined that the defrosting operation of system 2 has ended, the system waits until the defrosting operation of system 1 is completed in step 〓〓, and then returns to step 〓〓.
, timer T1 and timer T2 have the first
Set the defrosting operation prohibition time t1, and then
The step is determined again.

Conversely, if it is determined in the above step that the defrosting operation of system 2 has not been completed,
At step 〓〓, it is determined whether or not the defrosting operation of system 1 has been completed, and if it has not been completed, the step is again determined. On the other hand, if it is determined in step 〓〓 that the defrosting operation of system 1 has ended, then in step 〓〓 the system waits until the defrosting operation of system 2 ends, and then performs the process of step 〓〓 above. .

() In the above step, it is determined that the heating operation control thermometer of the indoor unit on the system 1 side is OFF.In this case, in the step above, the heating operation control thermometer of the indoor unit on the system 2 side is determined to be OFF.
The processing is almost the same as the judgment and processing when it is determined that it is OFF, and it is simply system 1.
The only difference is that the determination and processing for system 2 and the determination and processing for system 2 are reversed, so a detailed explanation will be omitted.

To summarize the above, if it is determined that one of the systems is in a state where defrosting operation should be performed while the heating operation control thermometers of both systems are ON, defrosting operation is performed for both systems. Then, a relatively long first defrosting operation prohibition time t1 is set in the timers T1 and T2 of both systems. Then, when the heating operation control thermometer of only one system is ON, if that system is determined to be in a state where defrosting operation should be performed, the heating operation control thermometer is turned ON. Defrost operation is performed only on the system where the defrost operation is performed, and a relatively long first defrost operation prohibition time t1 is set in the timer of the system where the defrost operation was performed, and a relatively short first defrost operation prohibition time t1 is set in the timer of the other system. A second defrosting operation prohibition time t2 is set.

In other words, if only one of the systems is performing heating operation and the amount of frost buildup exceeds a predetermined amount, by having only that system perform defrosting operation, it is possible to prevent the amount of frost formation from being excessive. Since the defrosting operation was not performed for the remaining systems, by setting the defrosting operation prohibition time short, it is possible to prevent the amount of frost from becoming excessive.

FIG. 4 is a flowchart showing another embodiment, and the only difference from the embodiment shown in FIG. It is.

If the above determination is made, step 〓〓
Start the defrosting operation of system 2 at step 〓〓, turn off the heating operation control thermometer of the indoor unit on the side of system 1 at step 〓〓, and determine whether the defrosting operation of system 2 has ended at step 〓〓. However, if the process has not been completed, the process of step 〓〓 is performed again. On the other hand, if it is determined that the defrosting operation of system 2 has ended in step <<>, a relatively long defrosting operation prohibition time t1 is set in timer T2 in step <<>, and the step is determined again.

Therefore, in the case of this embodiment, when the system for which the relatively short defrosting operation prohibition time t2 is set is to perform the defrosting operation, the heating operation control thermometer of the other system is turned on. Forcibly turn it off,
Defrosting operation for the other system can be reliably prevented.

However, if it is determined that the heating operation control thermostat is OFF in the step, and then a series of determinations and processing is performed and it is determined that system 1 is in a state where defrosting operation should be performed, the situation shown in Figure 1 also applies. Although this embodiment is different from the embodiment shown in FIG. 1, the operation is almost the same as that described above (only system 1 and system 2 are exchanged), so a description thereof will be omitted.

Note that the present invention is not limited to the above-mentioned embodiments; for example, it is possible to share only the heat exchange fan or only the heat exchange fins, or to use three for one outdoor unit. The present invention can be applied to an air conditioning system to which the indoor units described above are connected, and various other design changes can be made without departing from the gist of the present invention.

<Effects of the Invention> As described above, the present invention makes it possible to cause only the system that is performing heating operation to perform defrosting operation when a state in which defrosting operation should be performed is detected in any system. A relatively long defrost operation prohibition time is set for the systems that are not performing heating operation, and a relatively short defrost operation prohibition time is set without causing defrost operation to be performed for systems that are not performing heating operation. On the other hand, it has the unique effect of being able to reliably prevent frost from forming to such an extent that it cannot be removed even if one defrosting operation is performed.

[Brief explanation of drawings]

Fig. 1 is a flowchart explaining the operation of the air conditioning system of the present invention, Fig. 2 is a block diagram showing the electrical configuration of the air conditioning system, Fig. 3 is a schematic diagram of the air conditioning system, and Fig. 4 is a diagram of other systems. Flowchart showing an example. 1...Outdoor unit, 2...Indoor unit, 3
... Compressor, 4 ... Heat exchange fin, 5 ... Heat exchange fan, 6 ... Thermistor, 7, 8 ... Microcomputer, 17 ... Thermistor for suction temperature detection, 18 ... Indoor coil temperature detection Thermistor for use.

Claims (1)

[Claims] 1 In an air conditioning system in which a common outdoor unit is equipped with a compressor compatible with multiple indoor units, and at least one of the heat exchange fan and heat exchange fins is shared, each indoor unit A heating operation state detection means detects that the heating operation is being performed, a frost formation detection means detects that frost has formed on the heat exchange fins corresponding to each compressor, and only one of the indoor units is in the heating operation. The output signal from the heating operation state detection means indicating that heating operation is being performed, and the output signal from the frost formation detection means indicating that frost has formed on the heat exchange fins of the system in which heating operation is being performed are input. A defrosting control means for performing a defrosting operation only on a system that is performing a heating operation, a timer means for setting a defrosting operation prohibition time for each system after the end of the defrosting operation, and a timer means for performing a defrosting operation. a timer setting means for setting a defrosting operation prohibition time of a timer means corresponding to a system in which defrosting operation is not performed to a relatively long predetermined time period, and setting a defrosting operation prohibition time of a timer means corresponding to a system in which defrosting operation is not performed to a relatively short predetermined time period; An air conditioning system comprising: