JP6468890B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner that performs a cooling operation by heat exchange between an outdoor unit and an indoor unit.

  Conventionally, in this type of air conditioner, as described in Patent Document 1, an outdoor unit and an indoor unit are connected by a refrigerant pipe using an HFC-based R410A to constitute a refrigeration cycle. Some consisted of capillary tubes.

Japanese Patent No. 3853550

  Here, in recent years, R32 refrigerant has been used in air conditioners instead of R410A refrigerant that has been widely used in air conditioners. It is known that this R32 refrigerant has a higher refrigeration capacity per unit volume than the R410A refrigerant and can reduce the filling amount in the refrigerant pipe compared to the R410A refrigerant. In that case, as described above, When the pressure is reduced on the upstream side of the evaporator, it is necessary to make the pressure reduction rate about twice as high as that in the conventional air conditioner for the R410A refrigerant.

  Immediately after starting the compressor (compressor for R32 refrigerant) in the air conditioner for R32 refrigerant due to a decrease in filling amount and an increase in pressure reduction rate in R32 refrigerant (compared to R410A refrigerant). As a result, the refrigerant temperature (inlet refrigerant temperature) at the inlet of the indoor heat exchanger (evaporator) is extremely lowered and the temperature balance of the entire evaporator is lost, so that it takes time to stabilize the state of the refrigeration cycle. It will be.

  At this time, when using an expansion valve whose opening degree can be adjusted for pressure reduction on the upstream side of the evaporator, a decrease in the inlet refrigerant temperature can be suppressed by appropriately adjusting the opening degree of the expansion valve. However, when the capillary tube is used as a pressure reducer as in the conventional one, the degree of pressure reduction cannot be adjusted as in the expansion valve, and thus the state where the refrigeration cycle is unstable is relatively long. It will last for hours. As a result, a large temperature difference occurs between the inlet side portion and the intermediate portion and the outlet side portion of the pipe line in the indoor heat exchanger, and the low temperature wind that has passed through the inlet side portion and the outlet side portion have passed. There was a problem that harmful effects such as dew condensation inside the indoor unit could occur due to the mixing of slightly hot air.

In order to solve the above problem, in claim 1 of the present invention, in the air conditioner for R32 refrigerant in which an outdoor unit and an indoor unit are connected by a refrigerant pipe using R32 refrigerant, the indoor unit is The R32 refrigerant compressor includes an indoor heat exchanger that exchanges heat between the R32 refrigerant and room air, and an indoor fan that blows air to the indoor heat exchanger, and the outdoor unit compresses the R32 refrigerant. And an outdoor heat exchanger for exchanging heat between the R32 refrigerant and the outside air, and the R32 refrigerant at a pressure reduction rate N times (where 1 <N ≦ 2) the pressure reduction rate of the R410A in the air conditioner for the R410A refrigerant. And an outdoor fan that blows air to the outdoor heat exchanger, and an outdoor control unit that controls at least the rotational speed of the compressor. The outdoor control unit is a compressor for the R32 refrigerant. Has started The elapsed time until reaching the predetermined target rotational speed reaches the predetermined target rotational speed after activation of the R410A refrigerant compressor that compresses the R410A refrigerant in the R410A refrigerant air conditioner. Compressor control means for controlling the rotational speed of the compressor for the R32 refrigerant so as to be M times the elapsed time up to (where 1 <M ≦ N).

  According to a second aspect of the present invention, the compressor control means includes the R32 so that the R32 refrigerant reaches the predetermined target rotation speed after being held at a predetermined start-up guaranteed rotation speed after the R32 refrigerant compressor is started. The number of revolutions of the refrigerant compressor is controlled.

According to a third aspect of the present invention, when the compressor control means continuously increases the rotational speed of the compressor for R32 refrigerant in a state other than the holding state at the predetermined start-up guaranteed rotational speed, the rate of increase is the R410A. becomes the predetermined guaranteed activations outside holding state by the rotation speed the one or smaller than the increase rate when the R410A rotational speed of the compressor of the refrigerant is continuously increased 1 / M times the air conditioner refrigerant Thus, the rotation speed of the compressor for the R32 refrigerant is controlled.

According to a fourth aspect of the present invention, the compressor control means performs the predetermined start-up when the R32 refrigerant compressor reaches the predetermined target rotational speed through the predetermined start-up guaranteed rotational speed after starting up the R32 refrigerant compressor. When the retention time at the guaranteed rotational speed reaches the predetermined target rotational speed through the predetermined startup guaranteed rotational speed after the R410A refrigerant compressor is started in the R410A refrigerant air conditioner. so that the predetermined guaranteed activations one or longer than the retention time in the rotation speed M times or less, and controls the rotational speed of the compressor for the R32 refrigerant.

Moreover, in claim 5, wherein the capillary tube, the R410A at twice the pressure reduction rate of the pressure reduction rate of the R410A in an air conditioner in vacuo the R32 refrigerant for the refrigerant, the compressor control means, wherein R32 refrigerant The elapsed time from when the compressor for starting up to the predetermined target rotational speed is reached after the compressor for R410A refrigerant that compresses the R410A refrigerant in the air conditioner for R410A refrigerant is started. to be twice the time elapsed to reach the predetermined target rotational speed, and controls the rotational speed of the compressor for the R32 refrigerant.

  According to claim 1 of the present invention, the indoor unit includes an indoor heat exchanger and an indoor fan, and the outdoor unit includes a compressor, an outdoor heat exchanger, a capillary tube, and an outdoor fan, These are connected by refrigerant piping to construct a refrigeration cycle. That is, for example, when cooling operation is performed, after the refrigerant of gas sucked at low temperature and low pressure is compressed by the compressor to become high temperature and high pressure gas, the outdoor heat exchanger (condenser) By being cooled by the air blown by the fan, it changes into a high-pressure liquid while releasing heat to the outside air. The refrigerant thus turned into a liquid is decompressed by the capillary tube, becomes a low-pressure liquid, and is easily evaporated. Thereafter, the low-pressure liquid evaporates in the indoor heat exchanger (evaporator) and changes to gas, thereby absorbing heat from indoor air and cooling. The refrigerant then returns to the compressor again as a low-temperature and low-pressure gas.

  Here, the inventors of the present application have taken measures to eliminate the unstable state of the refrigeration cycle caused by using R32 refrigerant instead of R410A refrigerant and using a capillary tube instead of an expansion valve as described above. As a result of the examination, it has been newly found that the elapsed time when the rotational speed is increased after starting the compressor may be increased at a rate commensurate with the increase in the decompression rate.

  That is, normally, in the rotation speed control of the compressor in the air conditioner, after the compressor is started, the rotation speed is sequentially increased in a predetermined manner and finally reaches a predetermined target rotation speed. On the other hand, according to claim 1, the compressor control means provided in the outdoor control unit of the outdoor unit corresponding to the use of the R32 refrigerant and the capillary tube is configured so that the compressor is started after the compressor is started. The elapsed time until reaching the target rotational speed is set to twice as much as the maximum when compared with the case of using the R410A refrigerant (M times under the condition of 1 <N ≦ 2 1 <M ≦ N). In this way, by making the rotational speed increase behavior of the compressor moderate, it is possible to suppress an extreme decrease in the inlet refrigerant temperature in the R32 refrigerant and to reduce the change in the temperature balance of the entire evaporator. As a result, the state of the refrigeration cycle can be stabilized in a relatively short time, and adverse effects such as condensation can be avoided.

  According to the second aspect of the present invention, instead of suddenly reaching the target rotational speed after starting the compressor, the rotational speed increase is temporarily stopped and the rotational speed is maintained for a predetermined time at the predetermined start-up guaranteed rotational speed. Thereby, the desired compression performance in a compressor can be obtained stably and reliably.

  According to the third aspect of the present invention, the increase in the rotational speed of the compressor is ensured by gradual increase rate when the rotational speed of the compressor is continuously increased except in the holding state by the guaranteed start-up rotational speed. Can be relaxed. As a result, an extreme decrease in the inlet refrigerant temperature in the R32 refrigerant can be reliably suppressed, and the state of the refrigeration cycle can be reliably stabilized in a short time.

  According to a fourth aspect of the present invention, when continuously increasing the rotation speed of the compressor while passing through the holding state at the guaranteed start-up rotation speed, the rotation speed of the compressor is increased by increasing the holding time in the holding state. The ascending behavior can be made moderate gradually. As a result, an extreme decrease in the inlet refrigerant temperature in the R32 refrigerant can be reliably suppressed, and the state of the refrigeration cycle can be reliably stabilized in a short time.

  According to the fifth aspect of the present invention, the increase in the rotational speed of the compressor can be moderated to about 1/2. As a result, an extreme decrease in the inlet refrigerant temperature in the R32 refrigerant can be further reliably suppressed, and the state of the refrigeration cycle can be more reliably stabilized in a short time.

The figure which represented typically the refrigerating cycle at the time of the cooling operation of the air conditioner of one Embodiment of this invention. Side sectional view showing the internal structure of the indoor unit The figure which shows the time-dependent change of the inlet refrigerant temperature in a comparative example Side sectional view showing the internal behavior of the indoor unit before the refrigeration cycle is stabilized The figure which shows the time-dependent change of the inlet refrigerant temperature and compressor rotation speed at the time of doubling the processing time of the speed increasing process The figure which shows the time-dependent change of the inlet refrigerant temperature and the compressor rotation speed when the processing time of the holding process is doubled. The figure which shows the time-dependent change of an inlet refrigerant temperature and a compressor rotation speed at the time of doubling the processing time of both a holding | maintenance process and an acceleration process. The flowchart figure which shows the control procedure for implement | achieving control of compressor rotation speed

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  The overall schematic configuration of the air conditioner of the present embodiment is shown in FIG. In FIG. 1, the air conditioner 1 installs the indoor unit 2 by exchanging heat between the indoor unit 2 and the outdoor unit 3 with respect to the refrigerant circulating between the indoor unit 2 and the outdoor unit 3. The air temperature in the indoor side is adjusted. In this air conditioner 1, R32 refrigerant that has been used in recent years is used as the refrigerant instead of R410A refrigerant that has been widely used in air conditioners. The indoor unit 2 includes an indoor heat exchanger 4 that exchanges heat between a refrigerant (that is, an R32 refrigerant; the same applies hereinafter) and indoor air, an indoor fan 5 that blows air to the indoor heat exchanger 4, and the indoor unit 2 An outdoor unit 3 that controls the operation, and the outdoor unit 3 is an outdoor unit that exchanges heat between the refrigerant and the outside air, a four-way valve 7 that switches the circulation direction of the refrigerant, a compressor 8 that compresses the refrigerant, and the like. It has a heat exchanger 9, a capillary tube 10 that decompresses the refrigerant, an outdoor fan 11 that blows air to the outdoor heat exchanger 9, and an outdoor unit controller 12 that controls the operation of the outdoor unit 3.

  The four-way valve 7 is a rotary valve having four ports, and switches which of the two ports for the other sub-path 22 is connected to each of the two ports for the main path 21. The two ports for the sub-path 22 are connected by a refrigerant pipe of the sub-path 22 arranged in a loop shape, and the compressor 8 is provided on the sub-path 22.

  The compressor 8 functions as a pump for increasing the pressure of the refrigerant in the low-pressure gas state to the high-pressure gas state and circulating the refrigerant in the entire refrigerant pipe in the air conditioner 1.

  Further, the two ports for the main path 21 of the four-way valve 7 are connected by a refrigerant pipe of the main path 21 arranged in a loop shape, and the outdoor heat exchanger 9 and the capillary tube are disposed on the main path 21. 10 and the indoor heat exchanger 4 are provided in order (in the example shown, in the order of counterclockwise rotation of the main path 21).

  When the temperature of the gaseous refrigerant passing through the interior of the outdoor heat exchanger 9 is higher than the outdoor outside air temperature, the outdoor heat exchanger 9 functions as a condenser that dissipates heat of the refrigerant and condenses it into a liquid state. Further, when the temperature of the liquid refrigerant passing through the inside is lower than the outdoor outside air temperature, the refrigerant functions as an evaporator that absorbs the heat of the outside air into the refrigerant and evaporates it into a gas state. The indoor heat exchanger 4 functions in the same manner as the outdoor heat exchanger in the relationship between indoor air and refrigerant.

  The outdoor fan 11 and the indoor fan 5 improve the performance of each heat exchanger by sending air to the corresponding outdoor heat exchanger 9 and the indoor heat exchanger 4, respectively.

  The capillary tube 10 functions to depressurize the refrigerant in the high-pressure liquid state into a low-pressure liquid state.

  The outdoor unit control unit 12 and the indoor unit control unit 6 are mainly composed of a microcomputer including a CPU, a ROM, a RAM, and the like, respectively, and are based on instructions from a user via an operation unit such as a remote controller (not shown). In cooperation with each other, the entire air conditioner 1 is controlled. The outdoor unit control unit 12 mainly controls the four-way valve 7, the compressor 8, and the outdoor fan 11 included in the outdoor unit 3, and the indoor unit control unit 6 mainly controls the indoor fan included in the indoor unit 2. Control 5 is performed. In controlling the compressor 8, the outdoor fan 11, and the indoor fan 5, the number of rotations can be continuously variably controlled using an inverter or the like.

  The compressor 8 circulates the refrigerant in one direction on the sub-path 22, and controls the circulation direction of the refrigerant on the main path 21 by switching the four-way valve 7. For example, FIG. 1 shows the circulation direction during the cooling operation, and the refrigerant discharged from the compressor 8 flows in the order of the outdoor heat exchanger 9, the capillary tube 10, and the indoor heat exchanger 4. Thus, after the refrigerant in the gas state sucked at low temperature and low pressure is compressed by the compressor 8 to become high temperature and high pressure gas, the outdoor fan 11 in the outdoor heat exchanger 9 (functions as a condenser). It is changed to a high-pressure liquid while releasing heat to the outside air by being cooled by blowing air. The refrigerant that has become liquid in this manner is decompressed by the capillary tube 10 to become a low-pressure liquid and is in a state where it is easily evaporated. Thereafter, the low-pressure liquid evaporates in the indoor heat exchanger 4 (functions as an evaporator) and changes to gas, thereby absorbing heat from the indoor air and cooling it. The refrigerant then returns to the compressor 8 again as a low-temperature and low-pressure gas. By constructing the refrigeration cycle as described above, a cooling operation for reducing the temperature of the indoor air is performed.

  Although not specifically illustrated, by switching the four-way valve 7 to reverse the refrigerant circulation direction, the outdoor heat exchanger 9 functions as an evaporator, and the indoor heat exchanger 4 functions as a condenser. The heating operation can be performed to raise the temperature. In the following, only the operation during the cooling operation when the refrigeration cycle is constructed will be described.

  FIG. 2 is a side sectional view of the indoor unit 2 that schematically shows the structure of the indoor heat exchanger 4. In FIG. 2, the indoor heat exchanger 4 of the indoor unit 2 is a so-called “C” shape in which the upper ends of two heat exchangers 31 and 32 of two general finned tube heat exchangers are close to each other. It has a side sectional structure arranged in a mold. The finned tube heat exchanger is composed of a large number of heat transfer fins arranged in parallel and a copper tube (= tube) arranged meandering so as to penetrate the heat transfer fins. The structure of the heat exchangers 31 and 32 is omitted and schematically shown.

  During the cooling operation, the refrigerant pipe (corresponding to a copper pipe) of the main path 21 is inserted from the upper end inside each of the heat exchangers 31 and 32, is folded at the lower end, and is arranged so as to come out from the upper end. ing. Since the refrigerant pipe 21 is connected in series between the two heat exchangers 31 and 32, one of the heat exchangers 32 (the rear heat exchanger 32 in the illustrated example) is connected to the refrigerant flow path. The other heat exchanger 31 (the front heat exchanger 31 in the illustrated example) is located in the second half of the refrigerant flow path.

  In the air conditioner 1 having the basic configuration shown in FIGS. 1 and 2, the R32 refrigerant is used as described above. It is known that this R32 refrigerant generally has a higher refrigeration capacity per unit volume than the R410A refrigerant, and in order to exert the same refrigeration capacity, it can reduce the filling amount in the refrigerant pipe as compared with the R410A refrigerant. In that case, when the pressure is reduced on the upstream side of the evaporator (in this case, the indoor heat exchanger 4) as described above, the pressure reduction rate is larger than the pressure reduction rate in the conventional R410A refrigerant air conditioner. There is a need to. Note that the decompression rate in this specification means an index value indicating how much the refrigerant pressure before and after the change can be changed, and in the following, the greater the degree of decompression, the greater the decompression rate, The smaller the degree, the smaller the decompression rate.

  In the air conditioner 1 that uses the R32 refrigerant, the R32 refrigerant uses a decrease in filling amount (in comparison with the R410A refrigerant) and an increase in pressure reduction rate. The refrigerant temperature at the inlet of the indoor heat exchanger 4 (evaporator in this case) (inlet refrigerant temperature; for example, the temperature at point A in FIG. 1) is extremely lowered, and as a result, the temperature balance of the entire evaporator is lost. It takes time to stabilize the state of the refrigeration cycle.

  Such an unstable state of the refrigeration cycle and the subsequent behavior to stabilization will be described with reference to FIG. FIG. 3 shows the rotational speed control of the compressor 8 in the air conditioner 1 using R32 refrigerant, while the pressure reduction rate is double that of R410A (with the rotational speed control of this embodiment described later). Different) The time-dependent change of the inlet refrigerant temperature in the case of performing the same method as in the case of using the normal R410A is shown as a comparative example.

  That is, in the rotational speed control of the compressor 8 in the air conditioner 1 in this comparative example, after the compressor 8 is started, the rotational speed is sequentially increased in a predetermined manner, and finally a predetermined target rotational speed. Let the number reach. Specifically, first, immediately after the start of the operation of the air conditioner 1, the rotational speed of the compressor 8 is continuously increased at a predetermined increase rate from the state where the rotational speed of the compressor 8 is not rotating (0 rps). . Then, after the rotation speed of the compressor 8 reaches a predetermined start-up guaranteed rotation speed (about 60 rps in the illustrated example), a predetermined holding time (in the illustrated example, the elapsed time after the start of operation is about 60 to 120 seconds). During this period, the startup guaranteed rotation speed is held. After the holding time has elapsed, until the predetermined target rotational speed (approximately 80 rps in the illustrated example) is reached (in the illustrated example, the elapsed time after the start of operation is approximately 120 to 140 seconds), again at the predetermined increase rate. The rotational speed of the compressor 8 is continuously increased, and after reaching, the target rotational speed is maintained until the end of operation.

  Note that the rotational speed control in this manner is normally required due to the structural characteristics of the compressor 8. That is, in order to perform the circulation and compression of the refrigerant at the same time, mechanical parts having a large inertia are complicatedly linked in the compressor 8, and in order to operate them smoothly, the rotational speed can be increased over time. Necessary. In particular, with respect to maintaining the start-up guaranteed rotational speed for the holding time, the process is necessary for smooth and stable operation by sufficiently flowing lubricating oil to each part in the compressor 8. It is.

  With the rotation control of the compressor 8 as described above, the inlet refrigerant temperature exhibits the following behavior. That is, at the start of operation of the air conditioner 1 (time = 0), the inlet refrigerant temperature is the same temperature as the room air (about 26 ° C. in the illustrated example). Thereafter, when the operation starts, the refrigerant circulates on the main path 21, and when the refrigerant whose temperature is reduced by the pressure reduction in the capillary tube 10 reaches the inlet (the point A) of the evaporator (in the illustrated example, the operation starts. About 20 seconds after) the inlet refrigerant temperature begins to drop. Then, as described above, the charging amount of the R32 refrigerant is small and the decompression rate is large, so that the inlet refrigerant temperature is excessively lowered, and the excessively low temperature is significantly lower than the target temperature (about 13 ° C. in the illustrated example). The state (about 7 ° C. in the illustrated example) is reached, and the refrigeration cycle becomes unstable. However, when the circulation of the R32 refrigerant proceeds thereafter and the evaporation and condensation operations can be performed stably, the inlet refrigerant temperature starts to rise again and reaches the target temperature (in the example shown, from the start of operation). After about 210 seconds), the refrigeration cycle is stable.

  For the above operating characteristics, if an expansion valve whose opening can be adjusted for decompression upstream of the evaporator can be used, the opening of the expansion valve should be adjusted appropriately. Thus, an excessive decrease in the inlet refrigerant temperature can be suppressed. However, when the capillary tube 10 is used as in the air conditioner 1, the refrigeration cycle as described above is unstable (because the degree of pressure reduction cannot be adjusted as in the expansion valve). Will last for a long time.

  When such an unstable state continues for a long time, the following adverse effects may occur in the indoor heat exchanger 4 having the configuration shown in FIG. That is, when the unstable state continues for a long time, as shown in FIG. 4, the heat exchanger 32 corresponding to the first half portion of the refrigerant flow path near the point A extremely decreases in temperature, and in the second half portion. The corresponding heat exchanger 31 is in a relatively high temperature state (see also the shade color representing the low temperature state of the main path 21 in FIG. 4). Of the indoor air that has flowed into the indoor unit 2 (abbreviated as “room temperature wind” in the drawing), the low-temperature wind that has passed through the rear heat exchanger 32 (hereinafter simply referred to as “supercooled wind” as appropriate). The same applies to each figure, and the interior of the indoor unit 2 (especially the indoor fan 5) is excessively cooled, and a slightly high temperature wind (hereinafter, simply referred to as “cooling air” as appropriate) after passing through the front heat exchanger 31. When the inside of the indoor unit 2 that has been excessively cooled (especially the indoor fan 5) touches the inside of the indoor unit 2 (especially the indoor fan 5), dew condensation occurs in the indoor unit 2 (especially the indoor fan 5) and the air contains a lot of moisture. (Hereinafter, simply referred to as “condensation wind” as appropriate. The same applies in each figure). That is, when the unstable state of the refrigeration cycle continues for a long time as described above, a large deviation occurs in the temperature of the wind passing through each part of the indoor heat exchanger 4, and as a result, in the indoor unit 2 Internal condensation will occur.

  As a result of examining the above-described measures for eliminating the unstable state of the refrigeration cycle caused by using the R32 refrigerant instead of the R410A refrigerant and using the capillary tube 10 instead of the expansion valve, the inventors of the present application, etc. Has newly found that the elapsed time when the rotational speed is increased after starting the compressor 8 should be increased at a rate commensurate with the increase in the decompression rate.

  That is, when the pressure reduction rate when the R32 refrigerant is used is N times the pressure reduction rate when the R410A refrigerant is used (where 1 <N ≦ 2), the compressor 8 corresponds to the use of the capillary tube 10. The elapsed time after reaching the target rotational speed (the same value as the target rotational speed of the R410A refrigerant) after starting is also set to the N times when the R410A refrigerant is used. In this way, by making the rotational speed increase behavior of the compressor 8 gentle, an extreme decrease in the inlet refrigerant temperature in the R32 refrigerant is suppressed, and the change in the temperature balance of the entire indoor heat exchanger 4 is reduced. I found out that

  Here, as the type of the rotation speed control process from when the compressor 8 is started up until the predetermined target rotation speed is reached, the predetermined increase rate (the slope of the straight line rising to the right in FIG. 3) is used. ) Continuously increasing the number of revolutions (the elapsed time after the start of operation in FIG. 3 is about 0 to about 60 seconds, the elapsed time after the start of operation is about 120 to about 140 seconds; hereinafter referred to as “acceleration stroke” as appropriate) ) And a stroke for holding the predetermined start-up guaranteed rotational speed during the holding time (elapsed time after operation start in FIG. 3 is about 60 to about 120 seconds; hereinafter referred to as “holding stroke” as appropriate). There are two types. According to the study by the inventors of the present application, a method of taking a longer processing time for the speed increasing stroke than when using the R410A refrigerant and a method of taking a longer processing time for the holding stroke than when using the R410A refrigerant, It has been found that a unique effect can be obtained for each change in the inlet refrigerant temperature with time. The details will be described below with reference to FIGS.

  First, in FIG. 5, when the processing time of the speed increasing process is doubled (that is, N times) as compared with the comparative example of FIG. 3, in other words, the rate of increase in the rotational speed of the compressor 8 is halved (that is, The time-dependent change of the inlet refrigerant temperature and the compressor rotational speed in the case of (1 / N times) is shown. For easy comparison, the change with time in the comparative example of FIG. 3 is also shown by a dotted line (the same applies to corresponding drawings).

  That is, as shown in FIG. 5, in the rotation control of the compressor 8 in this case, during the elapsed time from the start of operation to about 120 seconds, the increase rate of the rotation speed is halved for the first time. The speed increasing process is performed. Thereafter, as in FIG. 3, the holding stroke is performed for about 60 seconds between about 120 to about 180 seconds after the start of operation. Then, during the elapsed time after the start of operation of about 180 to about 220 seconds, the second speed increase stroke is performed in which the rate of increase in the rotation speed is ½ times as in the first time. In this way, the processing time in the two speed increasing steps is doubled, and the rate of increase in the rotational speed of the compressor 8 is moderated, so that the above-mentioned target when the inlet refrigerant temperature becomes an excessively low temperature state is set as the target. The maximum temperature difference ΔKn with respect to the temperature can be made smaller than the maximum temperature difference ΔKo in the comparative example. That is, it has been found that by taking a longer processing time for the speed increasing process, it is possible to suppress the lowering behavior of the inlet refrigerant temperature and raise the minimum temperature.

  Next, in FIG. 6, when the processing time of the holding process is doubled (that is, N times) as compared with the comparative example of FIG. 3, in other words, the holding time of the startup guaranteed rotation speed is doubled (that is, N times). FIG. 6 shows changes with time in the inlet refrigerant temperature and the compressor rotational speed in the case of the above.

  That is, as shown in FIG. 6, in the rotation control of the compressor 8 in this case, during the elapsed time from the start of operation to about 60 seconds, the increase rate of the rotation speed is made the same as that of the comparative example. The speed increasing process is performed. Thereafter, the holding stroke is performed for about 120 seconds (twice that of the comparative example) between about 60 to about 180 seconds after the start of operation. Then, during the elapsed time after the start of operation of about 180 to about 200 seconds, the second speed increase stroke is performed in the same manner as the first time, with the rate of increase in the rotational speed being equal to that of the comparative example. In this way, by doubling the processing time in the holding process, the time difference ΔTn until the inlet refrigerant temperature falls below the target temperature and then returns to the target temperature is set to the value of the comparative example. The time difference ΔTo can be shortened. That is, by taking a longer processing time for the holding process, the time during which the refrigeration cycle is in an unstable state can be shortened, and the temperature drop at the second stage as in the comparative example is eliminated, and the inlet refrigerant temperature is reduced. It was found that the minimum temperature can be raised while suppressing the lowering behavior.

  Based on the above considerations, the inventors of the present invention set the decompression rate in the capillary tube 10 to twice the decompression rate when using the R410A refrigerant (that is, N = 2) in the air conditioner 1 of the present embodiment, and In the rotational speed control of the compressor 8 executed by the outdoor unit control unit 12, the processing time in both the acceleration stroke and the holding stroke is doubled when the R410A refrigerant is used (that is, N = 2). ).

  That is, as shown in FIG. 7, in the rotation control of the compressor 8 executed by the outdoor unit control unit 12 of the air conditioner 1 of the present embodiment, during the elapsed time from the start of operation to about 120 seconds, The first speed increasing step is performed in which the rate of increase in the rotational speed is ½ times that of the comparative example. Thereafter, the holding process is performed for about 120 seconds (twice that of the comparative example) between about 120 to about 240 seconds after the start of operation. Then, during the elapsed time after the start of operation of about 240 to about 280 seconds, the second speed increase stroke is performed in which the increase rate of the rotation speed is ½ times as in the first time. As a result of such control, the elapsed time from when the compressor 8 is started until it reaches the target rotational speed reaches the target rotational speed after the compressor is started in the R410A refrigerant air conditioner. Is approximately twice the elapsed time (see dotted line behavior in the figure) (140 seconds → 280 seconds), realizing both the increase in the minimum inlet refrigerant temperature and the shortening of the instability period of the refrigeration cycle Can do.

  In the example shown in FIG. 5, the outdoor unit controller 12 is assumed to have a decompression rate in the capillary tube 10 that is N times the decompression rate when the R410A refrigerant is used (N = 2 in the above example). In the rotation speed control of the compressor 8 to be executed, the processing time in the speed increasing process is set to N times (N = 2 in the above example) when the R410A refrigerant is used, so that the speed increasing process and the holding process are performed. The total processing time is about 1.57 times (= 220/150) smaller than 2 times (greater than 1 time). In the example shown in FIG. 6 as well, the outdoor unit controller 12 is assumed to have a decompression rate in the capillary tube 10 that is N times the decompression rate when the R410A refrigerant is used (N = 2 in the above example). In the rotation speed control of the compressor 8 to be executed, the processing time in the holding stroke is set to N times (N = 2 in the above example) when the R410A refrigerant is used, so that the speed increasing stroke and the holding stroke can be reduced. The total processing time is about 1.43 times (= 200/150) which is smaller than twice (greater than 1 time). In any of these cases, as described above, at least the effect of reducing the change in temperature balance of the entire indoor heat exchanger 4 can be obtained. Therefore, in order to obtain this effect, the total processing time of the speed increasing stroke and the holding stroke is approximately M times larger than 1 time when the R410A refrigerant is used and smaller than N times (where 1 <M ≦ N) is sufficient. And as a result of further studying this and the inventors of the present application, the processing time of either the speed increasing stroke or the holding stroke is set to be larger than 1 time when the R410A refrigerant is used and more than N times. It was found that even when the size is small and approximately M times (however, 1 <M ≦ N), the change in the temperature balance of the entire indoor heat exchanger 4 can be reduced at least as compared with the comparative example.

  Next, a control procedure executed by the CPU (not shown) of the outdoor unit controller 12 in order to realize the rotational speed control of the compressor 8 of the present embodiment shown in FIG. 7 will be described with reference to FIG. To do. The control procedure starts to be executed when a cooling operation start operation is input via an operation unit such as a remote controller (not shown). FIG. 8 shows only the control procedure performed by the outdoor unit control unit 12 for the compressor 8. In addition, the outdoor unit control unit 12 has a four-way valve at the start of this control procedure. 7 is switched to the cooling operation state and the operation of the outdoor fan 11 is started, and the operation of the indoor fan 5 is also started in the indoor unit control unit 6 (not shown).

  First, the value of the rotation speed variable V is reset to 0 (S5). Thereafter, the compressor 8 is rotated at the rotational speed indicated by the rotational speed variable V at that time (initially 0 rps) (S10). At this time, the outdoor unit control unit 12 controls the rotational speed of the compressor 8 with high accuracy in response to a fine change in the rotational speed variable V by rotational control using the inverter.

  Thereafter, it is determined whether or not the value of the rotation speed variable V is equal to or greater than the start-up guaranteed rotation speed Vh (S15). If the value of the rotational speed variable V is still less than the startup guaranteed rotational speed Vh, the determination is not satisfied (S15: No), and the process proceeds to S20.

  In S20, after adding the speed deviation ΔV to the rotation speed variable V, the process returns to S10 and the same procedure is repeated. In this embodiment, the speed deviation ΔV corresponds to the rate of increase in the compressor speed per one loop processing time of S10, S15, and S20. As described above, the normal speed using the R410A refrigerant is used. It is set to (1 / N) times (here, N = 2) in the case of an air conditioner (the same applies to S45 described later).

  On the other hand, in the determination of S15, when the value of the rotation speed variable V is equal to or greater than the startup guaranteed rotation speed Vh, the determination is satisfied (S15: Yes), and the process proceeds to S25.

  In S25, a timer (not shown) provided in the outdoor unit control unit 12 is reset (T = 0), and the time measurement is started.

  Thereafter, it is determined whether or not the elapsed time T counted by the timer has passed the holding time Ts for the guaranteed start-up rotational speed (S30). In the present embodiment, as described above, the holding time Ts is set to N times (here, N = 2) in the case of a normal air conditioner using the R410A refrigerant, and the outdoor unit control unit 12 in advance. Is stored in the ROM. As long as the elapsed time T of the timer is less than the holding time Ts, the procedure of S30 is repeated and the start-up guaranteed rotational speed Vh of the compressor 8 is maintained.

  On the other hand, when the elapsed time T of the timer exceeds the holding time Ts, the determination in S30 is satisfied (S30: Yes), and the process proceeds to S35.

  In S35, the compressor 8 is rotated at the rotational speed indicated by the rotational speed variable V at that time (initially guaranteed start-up rotational speed Vh).

  Thereafter, it is determined whether or not the value of the rotational speed variable V is equal to or greater than the target rotational speed Vr (S40). In addition, this target rotation speed Vr is the same value as the target rotation speed of the normal air conditioner using R410A refrigerant. If the value of the rotational speed variable V is still less than the target rotational speed Vr, the determination is not satisfied (S40: No), and the process proceeds to S45.

  In S45, the speed deviation ΔV (which is the same value as S20, but may be a different value) is added to the rotation speed variable V, and then the process returns to S10 and the same procedure is repeated.

  On the other hand, if the value of the rotational speed variable V is equal to or greater than the target rotational speed Vr in the determination of S40, the determination is satisfied (S40: Yes), and the process proceeds to S50.

  In S50, it is determined whether or not the operation end operation of the air conditioner 1 has been input via an operation unit such as a remote controller (not shown). If the operation end operation has not been input, the determination is not satisfied (S50: No), and the procedure of S50 is repeated.

  On the other hand, when the operation end operation is input, the determination is satisfied (S50: Yes), and the process proceeds to S55. In S55, the operation of the outdoor unit 3 is stopped including the rotation stop of the compressor 8, and this flow is finished.

  The CPU that executes the entire control procedure in FIG. 8 described above functions as the compressor control means described in each claim.

  As described above, according to the air conditioner 1 of the present embodiment, it is possible to cope with the use of the R32 refrigerant and the capillary tube 10 (the pressure reduction rate is N times the pressure reduction rate when the R410A refrigerant is used). When the outdoor unit control unit 12 uses the R410A refrigerant so that the elapsed time until the target rotational speed is reached after the compressor 8 is started is equal to the pressure reduction rate in the capillary tube. Is approximately M times (1 <M ≦ N: that is, twice the maximum under the condition of 1 <N ≦ 2). In this way, by making the rotational speed increase behavior of the compressor 8 gentle, an extreme decrease in the inlet refrigerant temperature in the R32 refrigerant is suppressed, and the change in the temperature balance of the entire indoor heat exchanger 4 is reduced. Can do. As a result, the state of the refrigeration cycle can be stabilized in a relatively short time, and adverse effects such as condensation can be avoided. By setting M ≦ N so that it does not exceed N times, it is possible to prevent an unnecessary increase in the start-up time of the refrigeration cycle (≈time for driving at a target rotational speed or less). There is also an effect that can be achieved.

  In this embodiment, in particular, the target rotational speed is not suddenly reached after the compressor 8 is started, but the rotational speed increase is temporarily stopped at a predetermined start-up guaranteed rotational speed Vh, and the rotational speed is maintained for a predetermined time. (The holding step). Thereby, the desired compression performance in the compressor 8 is stably and reliably obtained.

  Further, in the present embodiment, in particular, the speed increasing rate in the speed increasing stroke (when the rotational speed of the compressor 8 is continuously increased with respect to the use of the R32 refrigerant, except in the holding state at the startup guaranteed rotational speed Vh ( (Corresponding to the speed deviation ΔV)). In the above-mentioned example, it is set to approximately (1 / M) times (M = N = 2 in the above example) in the normal case using the R410A refrigerant. As a result, the rotational speed increasing behavior of the compressor 8 can be surely moderated. As a result, an extreme decrease in the inlet refrigerant temperature in the R32 refrigerant can be reliably suppressed, and the state of the refrigeration cycle is reliably stabilized in a short time.

  In the present embodiment, in particular, when the rotation speed of the compressor 8 is continuously increased while maintaining the holding state at the startup guaranteed rotation speed Vh, the holding time Ts in the holding stroke is lengthened. In the above-described example, it is set to approximately M times (M = N = 2 in the above example) in the normal case using the R410A refrigerant. As a result, the rotational speed increasing behavior of the compressor 8 can be surely moderated. As a result, an extreme decrease in the inlet refrigerant temperature in the R32 refrigerant can be reliably suppressed, and the state of the refrigeration cycle is reliably stabilized in a short time.

  At this time, the holding time Ts of the guaranteed start-up rotational speed is set to N times (N = 2) in the normal case using the R410A refrigerant, but is not limited thereto. If the holding time Ts is set at least longer than the normal holding time using the R410A refrigerant and approximately N times or less, the unstable state time of the refrigeration cycle can be shortened.

  In the present embodiment, in particular, the capillary tube 10 decompresses the R32 refrigerant at a decompression rate approximately twice the decompression rate in the R410A refrigerant air conditioner. Further, the outdoor unit controller 12 determines the elapsed time from when the compressor 8 is started until the target rotational speed is reached in the air conditioner for R410A refrigerant corresponding to the increase in the decompression rate. The rotational speed of the compressor 8 is controlled so as to be approximately twice the elapsed time. As a result, the rotational speed increase behavior of the compressor 8 can be moderated to about ½ (see FIG. 7), so that an extreme decrease in the inlet refrigerant temperature in the R32 refrigerant can be further reliably suppressed. The state of the refrigeration cycle is more reliably stabilized in a short time.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not change the summary of invention.

DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Indoor unit 3 Outdoor unit 4 Indoor heat exchanger 5 Indoor fan 6 Indoor unit control part 7 Four-way valve 8 Compressor (compressor for R32 refrigerant)
9 Outdoor heat exchanger 10 Capillary tube 11 Outdoor fan 12 Outdoor unit controller 21 Main path (refrigerant piping)
22 Sub route (refrigerant piping)
31 Front side heat exchanger 32 Back side heat exchanger

Claims (5)

In the air conditioner for R32 refrigerant, in which the outdoor unit and the indoor unit are connected by a refrigerant pipe using R32 refrigerant,
The indoor unit is
An indoor heat exchanger for exchanging heat between the R32 refrigerant and room air;
An indoor fan for blowing air to the indoor heat exchanger;
The outdoor unit is
A compressor for the R32 refrigerant that compresses the R32 refrigerant;
An outdoor heat exchanger for exchanging heat between the R32 refrigerant and outside air;
A capillary tube for reducing the pressure of the R32 refrigerant at a pressure reduction rate N times (where 1 <N ≦ 2) of the pressure reduction rate of the R410A in the air conditioner for the R410A refrigerant;
An outdoor fan that blows air to the outdoor heat exchanger;
An outdoor control unit that controls at least the rotational speed of the compressor,
The outdoor control unit is
The R410A refrigerant compressor that compresses the R410A refrigerant in the air conditioner for R410A refrigerant is activated after the R32 refrigerant compressor is activated until it reaches a predetermined target rotational speed. Compressor control means for controlling the rotational speed of the compressor for the R32 refrigerant so that it is M times the elapsed time from reaching the predetermined target rotational speed (where 1 <M ≦ N). An air conditioner comprising: The compressor control means includes
The rotation speed of the R32 refrigerant compressor is controlled so that the predetermined target rotation speed is reached after being held at a predetermined start-up guaranteed rotation speed after the R32 refrigerant compressor is started. The air conditioner according to claim 1. The compressor control means includes
The rate of increase when the rotational speed of the compressor for the R32 refrigerant is continuously increased in a state other than the holding state at the predetermined startup guaranteed rotational speed is equal to the predetermined guaranteed startup rotational speed in the air conditioner for the R410A refrigerant. as the rotational speed of the compressor for the R410A refrigerant becomes continuously or smaller than the increase rate one 1 / M times in increasing except holding state by the rotational speed of the compressor for the R32 refrigerant It controls, The air conditioner of Claim 2 characterized by the above-mentioned. The compressor control means includes
The holding time at the predetermined guaranteed rotation speed when the R32 refrigerant compressor starts up and reaches the predetermined target rotation speed after passing through the predetermined guaranteed rotation speed is determined for the R410A refrigerant. In the air conditioner, is it longer than the holding time at the predetermined guaranteed start speed when the R410A refrigerant compressor starts up and reaches the predetermined target speed through the predetermined start guaranteed speed? 4. The air conditioner according to claim 2, wherein the rotation speed of the compressor for the R32 refrigerant is controlled to be equal to or less than M times. 5. The capillary tube is
The R32 refrigerant and decompressed at twice the pressure reduction rate of the pressure reduction rate of the R410A in an air conditioner for the R410A refrigerant,
The compressor control means includes
The R410A refrigerant compressor that compresses the R410A refrigerant in the air conditioner for the R410A refrigerant is activated after the R32 refrigerant compressor is activated until it reaches a predetermined target rotational speed. 5. The rotation speed of the compressor for the R32 refrigerant is controlled so as to be twice as long as an elapsed time until the predetermined target rotation speed is reached. Item 1. An air conditioner according to item 1.

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