JP3651534B2 - Control method of air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an open / close degree control technique of an expansion valve (electronic expansion valve) included in a refrigeration cycle of an inverter type air conditioner, and more particularly, a temperature difference (SH) between a suction temperature of a compressor and a temperature of an evaporator. It is related with the control method of the air conditioner which performs what is called superheat control which adjusts quantity) to a target value.
[0002]
[Prior art]
For example, as shown in FIG. 4, this type of air conditioner has a refrigeration cycle including a compressor 1, a four-way valve 2, an indoor heat exchanger 3, an outdoor heat exchanger 4, and an electronic expansion valve 5.
[0003]
During the cooling operation, switching of the four-way valve 2 causes the refrigerant to flow from the indoor heat exchanger 3 to the compressor 1 according to the broken line arrow in FIG. 4, and from the compressor 1 to the outdoor heat exchanger 4 and the electronic expansion valve 5. While returning to the exchanger 3, the rotation of the indoor fan is controlled according to the air volume set by the remote controller, etc., the cold air exchanged by the indoor heat exchanger 3 is blown into the room, and the air temperature is set according to the difference between the room temperature and the remote controller set temperature. The compressor 1 is operated at a predetermined operating frequency to control the room temperature.
[0004]
In the heating operation, the refrigerant is returned from the outdoor heat exchanger 4 to the compressor 1 and from the compressor 1 to the outdoor heat exchanger 4 via the electronic expansion valve 5 (in contrast to the cooling operation) ( The rotation of the indoor fan is controlled according to the set air volume of the remote control, etc., and the hot air exchanged by the indoor heat exchanger 3 is blown into the room, and the difference between the room temperature and the set temperature of the remote control is determined. The room temperature is controlled by operating the compressor 1 at a predetermined operating frequency.
[0005]
Therefore, as shown in FIG. 5, an indoor unit control unit 6 and an outdoor unit control unit 7 are provided. The indoor unit control unit 6 controls the indoor fan according to an instruction from the remote controller, and a predetermined command ( The operation frequency according to the difference between the room temperature and the set value is transmitted, and the outdoor unit control unit controls the compressor 1 and the like according to the command.
[0006]
By the way, the outdoor unit control unit 7 performs superheat control that adjusts the difference (SH amount) between the suction temperature of the compressor 1 and the temperature of the evaporator (heat exchange temperature) to a target value (constant), that is, electronic The degree of opening / closing of the expansion valve 5 is controlled to a predetermined value. For example, the amount of SH is detected every minute, and the motor of the electronic expansion valve 5 is controlled according to the difference between the amount of SH and the target value. This suppresses abrupt changes in the refrigeration cycle, it is necessary to suppress an abrupt change in the Atsushi Muro. The target value is determined in consideration of the set temperature of the remote controller, room temperature, and the like.
[0007]
Therefore, an indoor heat exchange thermistor 8 that detects the temperature of the indoor heat exchanger 3, a suction thermistor 9 that detects the intake temperature of the compressor 1, and an outdoor heat exchange thermistor 10 that detects the temperature of the outdoor heat exchanger 4 are provided. Yes.
[0008]
[Problems to be solved by the invention]
However, in the control method for the air conditioner, there is one sensor for detecting the temperature of the evaporator, and therefore only one temperature of the evaporator can be detected. Therefore, superheat control is appropriately performed. In some cases, the evaporator was overheated and the optimum refrigeration cycle could not be performed, which in turn adversely affected room temperature control.
[0009]
For example, at the start of cooling operation, the evaporator inlet cools first and does not cool so quickly that it goes from the middle to the outlet side (see Fig. 6) , and the moisture is taken out in special conditions such as high humidity in the room during cooling operation. Therefore, when the middle of the evaporator is overheated or the frequency is increased during operation, the refrigerant inlet side becomes wet.
[0010]
Thus, stable non operation beginning of the refrigeration cycle, the conditions such as when changing the high humidity and operating frequency, temperature refrigerant inlet port side of the evaporator, will respectively different values in the middle and exit end , since only one sensor can not be obtained temperature suitable evaporator for superheat control the current, for example, or the electronic expansion valve 5 is rapidly throttled, overheating results evaporator, a problem in the refrigeration cycle come Will be.
[0011]
This invention is made in view of the said subject, The objective is the superheat control, The control method of the air conditioner which enabled it to control an expansion valve appropriately, without always overheating an evaporator Is to provide.
[0012]
[Means for Solving the Problems]
To achieve the above object, the present invention is to match the temperature difference between the temperature of the suction temperature of the compressor included in a refrigeration cycle evaporator (S-H content) in the target value, the refrigeration cycle the control method of an air conditioner for adjusting the opening degree of the expansion valve included, has a temperature detecting means at least two positions of the refrigerant inlet side and the intermediate portion of the evaporator, detected by the plurality of temperature detection means and the lowest temperature of the temperature determined in the temperature of the evaporator, characterized in that to perform the superheat controlled by the temperature difference between the temperature of the evaporator and the determined and the suction temperature of the compressor It is said.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to FIGS. In FIG. 1, the same parts as those in FIG. See FIG. 4 for the refrigeration cycle.
[0014]
In the air conditioner control method according to the present invention, if temperature detecting means are arranged at different portions of the evaporator, the current superheat control among the temperatures (heat exchange temperatures) of the evaporator detected by these temperature detecting means. Focusing on the fact that the best temperature can be obtained, the difference (S—H amount) between the refrigerant suction temperature of the compressor and the appropriate evaporator temperature is detected, and this S—H amount becomes the target value. Thus, the degree of opening and closing of the expansion valve is controlled to prevent overheating of the evaporator by superheat control.
[0015]
Therefore, as shown in FIG. 1, a control device to which the air conditioner control method of the present invention is applied includes an indoor heat exchange thermistor unit 11 and an outdoor heat exchange thermistor unit 12 each having a plurality of indoor heat exchange thermistors, In addition to the functions of the indoor unit control unit 6 shown in FIG. 5, the indoor unit control unit 13 that transfers the temperature detected by the indoor heat exchanger thermistor unit 11 to the outdoor unit control unit 14, and the outdoor unit control unit 7 shown in FIG. In addition to the above function, an outdoor unit control that determines one of the temperatures transferred from the indoor unit control unit 13 that is optimal for the current super heat control and performs the super heat control based on the determined temperature and the suction temperature. Part 14.
[0016]
As the plurality of indoor heat exchange thermistors, for example, as shown in FIG. 2, an indoor heat exchange thermistor 11a for detecting the temperature on the refrigerant inlet side of the indoor heat exchanger (evaporator in the case of cooling operation) 3 is provided. The indoor heat exchange thermistor 11b for detecting the temperature and the indoor heat exchange thermistor 11c for detecting the temperature on the outlet side are used.
[0017]
Incidentally, the indoor heat exchange thermistor may be a more number, for example between the refrigerant inlet port side and the intermediate may be added indoor heat exchange thermistor respectively between the middle and the outlet side or grid pattern, You may make it arrange | position like this. In consideration of cost, the indoor heat exchange thermistor 11c may be omitted, and only the two indoor heat exchange thermistors 11a and 11b on the refrigerant inlet side and the intermediate portion may be provided.
[0018]
The outdoor heat exchange thermistor section 12 is composed of a plurality of outdoor heat exchange thermistors arranged at a plurality of locations of the outdoor heat exchanger 4 as with the indoor heat exchange thermistor section 11, but the outdoor heat exchanger (evaporator in the case of heating operation). Since it is extremely rare for 4 to overheat, it may be one outdoor heat exchange thermistor as in the prior art.
[0019]
Next, when the operation of the control apparatus of the air conditioner of the structure will be described with reference to the graph of FIG. 3, the first cold tufts driving operation is performed by the remote control, the indoor unit control section 13 required for the climate A simple signal (such as operating frequency) is transferred to the outdoor unit control unit 14. The outdoor unit controller 14 drives at least the compressor 1 in a predetermined manner, sets the electronic expansion valve 5 to a predetermined opening / closing degree, and operates the refrigeration cycle. As in the prior art, the indoor unit control 13 and the outdoor unit control 14 perform other necessary controls (fan rotation control, etc.) to adjust the room temperature.
[0020]
At this time, the indoor unit control unit 13 transfers the evaporator temperature (indoor heat exchange temperature) detected by the indoor heat exchange thermistors 11a, 11b, and 11c to the outdoor unit control unit 14, and the outdoor unit control unit 14 is the same as the conventional unit. Then, a temperature difference (S—H amount) between the indoor heat exchange temperature and the suction temperature (suction temperature) of the compressor 1 is detected, and superheat control is performed so that this S—H amount becomes a target value.
[0021]
In this case, the outdoor unit control unit 14 determines the lowest temperature among the temperatures detected by the plurality of indoor heat exchange thermistors 11a, 11b, and 11c. For example, if the lowest indoor heat exchange temperature is the temperature detected by the indoor heat exchange thermistor 11a disposed on the inlet side at time t1 immediately after the start of operation, the difference between the suction temperature and the temperature on the inlet side is calculated. Detect and perform superheat control according to this temperature difference. According to this, even when the refrigeration cycle is not stable at the start of operation, the electronic expansion valve 5 is not squeezed more and more, and overheating of the evaporator can be prevented.
[0022]
At time t2, when the inlet side temperature rises by the super heat control described above and the intermediate temperature becomes the lowest, the difference between the temperature detected by the indoor heat exchanger thermistor 11b arranged in the middle and the suction temperature is detected, Superheat control is performed according to this temperature difference. Therefore, even if the inlet side temperature rises, the electronic expansion valve 5 is not squeezed more and more, and overheating of the evaporator can be prevented.
[0023]
At the time point t3, when the outlet side temperature becomes the lowest by the above-described superheat control, the difference between the temperature detected by the indoor heat exchanger thermistor 11c arranged on the outlet side and the suction temperature is detected, and according to this temperature difference Perform superheat control. In this case, the refrigeration cycle is extremely stable, the electronic expansion valve 5 can be ideally controlled, and the evaporator does not overheat. Further, for example, even if the inlet side temperature or the intermediate temperature rises differently from that shown in FIG. 3, superheat control is performed at the lowest temperature and the suction temperature, so that the evaporator does not overheat.
[0024]
Further, at the time t4, when the operating frequency of the compressor 1 is increased due to, for example, a remote controller setting operation (changing the operating frequency) or some n disturbance, the refrigerant inflow increases, whereby the inlet side temperature rapidly decreases. The lowest. Then, at time t5, the difference between the temperature detected by the indoor heat exchanger thermistor 11a arranged on the inlet side and the suction temperature is detected, and superheat control is performed according to this difference. Therefore, the electronic expansion valve 5 is not squeezed more and more, and the evaporator can be prevented from overheating.
[0025]
Thus, when the temperature of the evaporator has different values on the refrigerant input side, the intermediate side, and the output side due to conditions such as high humidity and changing the operation frequency at the beginning of unstable operation of the refrigeration cycle, Among these temperatures, the lowest temperature is set as the indoor heat exchange temperature, that is, a temperature favorable for the current superheat control (indoor heat exchange temperature) can be determined, and the electronic expansion valve 5 is always without overheating of the evaporator. Can be optimally controlled and does not interfere with the refrigeration cycle, that is, does not adversely affect the room temperature adjustment.
[0026]
Incidentally, the three indoor heat exchange thermistor 11a, 11b, the use of the 11c, indoor although the superheat control can be optimally performed, which omit the outlet side of the indoor heat exchange thermistor 11c, detects the inlet port side temperature The heat exchanger thermistor 11a and the indoor heat exchanger thermistor 11b for detecting the temperature of the intermediate portion may be used.
[0027]
In this case, even if the indoor heat exchanger thermistor 11c on the outlet side is reduced, overheating of the evaporator can be prevented. That is, since the intermediate temperature of the evaporator and the temperature on the outlet side are always close to each other, the indoor heat exchange thermistor 11c can also serve as the indoor heat exchange thermistor 11b. Further, if one indoor heat exchange thermistor is reduced, the cost increase is small, and it is extremely useful from the cost aspect.
[0028]
By the way, in the heating operation, the evaporator serves as the outdoor heat exchanger 4, and the same control as in the cooling operation described above is performed, so that the evaporator can be prevented from overheating. About this control, since it becomes duplication description, it abbreviate | omits. In addition, since the outside air temperature is low during the heating operation and the evaporator is rarely overheated as described above, one outdoor heat exchange thermistor may be used as in the conventional case.
[0029]
【The invention's effect】
As described above , according to the present invention, the temperature detecting means is provided in at least two locations of the refrigerant inlet side and the intermediate portion of the evaporator, and the lowest temperature among the temperatures detected by these temperature detecting means is determined. of determining the temperature, since to perform the superheat controlled by the temperature difference between the suction temperature of the compressor and the temperature of the evaporator with the determined optimum electronic expansion valve 5 without evaporator superheat always This has the useful effect of being able to control the refrigeration cycle.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of a control apparatus to which an air conditioner control method is applied according to an embodiment of the present invention.
FIG. 2 is a schematic front view for explaining an evaporator of an air conditioner according to the present invention.
FIG. 3 is a schematic graph for explaining the operation of the control device shown in FIG. 1;
FIG. 4 is a schematic configuration diagram for explaining a refrigeration cycle of an air conditioner.
FIG. 5 is a schematic block diagram for explaining a conventional control device for an air conditioner.
6 is a schematic graph for explaining the operation of the control device shown in FIG. 5;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Compressor 3 Indoor heat exchanger 4 Outdoor heat exchanger 5 Electronic expansion valve 6,13 Indoor unit control part 7,14 Outdoor unit control part 9 Suction thermistor (compressor suction temperature sensor)
11 indoor heat exchange thermistors 11a, 11b, 11c indoor heat exchange thermistors (temperature sensors)
12 Outdoor heat exchange thermistor

Claims (1)

The temperature difference between the suction temperature of the compressor included in a refrigeration cycle and temperature of the evaporator (S-H content) to match the target value, the air conditioner to adjust the opening degree of the expansion valve included in the freezing cycle In the control method of the machine,
Has a temperature detecting means at least two positions of the refrigerant inlet side and the intermediate portion of the evaporator, to determine the lowest temperature among the temperatures detected by the plurality of temperature detecting means temperature of the evaporator the control method of the air conditioner being characterized in that to perform the superheat controlled by the temperature difference between the temperature of the evaporator and the determined and the suction temperature of the compressor.

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