Air conditioning device

Abstract

[Problem] To provide an air conditioning device capable of shortening a standby time until a compressor can be started up, even in a mobile air conditioning device not comprising a detection means for pressure, and improving convenience for a user. [Solution] This mobile air conditioning device 100 accommodates, in a housing 1, a control unit 8 and a refrigerant circuit comprising a compressor 2, a condenser 4, a decompression device 7, and an evaporator 3, and comprises: a first temperature sensor 201 that detects the temperature of air which has performed heat exchange with the condenser 4; and a startup determination unit 83 that, when a startup request for the compressor 2 is generated, determines whether the compressor 2 can be started up on the basis of temperature information from the first temperature sensor 201.

Description

Air conditioner

[0001] The present invention relates to an air conditioner.

[0002] Conventionally, an air conditioner is known in which a compressor, a condenser, a decompressor, and an evaporator are connected in a loop by a refrigerant pipe, and heat exchange for heating is performed in the condenser while controlling the pressure of the refrigerant with the compressor and the decompressor, and heat exchange for cooling is performed in the evaporator. Also, a movable (portable) air conditioner in which a compressor, a condenser, a decompression device, an evaporator, a blower, a control device, etc. constituting a refrigerant circuit are housed in one housing has been developed. In a portable air conditioner, since the power of the air conditioner is turned on and off even when moving, the power is more frequently turned on and off compared to a stationary air conditioner.

[0003] In such an air conditioner, when the heat exchanger during operation is stopped, the pressure of the refrigerant is high on the discharge side of the compressor and low on the suction side of the compressor. When starting the compressor in a state where there is a pressure difference between the pressure of the refrigerant on the discharge side of the compressor and the pressure of the refrigerant on the suction side of the compressor, the compressor has to start while receiving the pressure difference, and there may be a failure to start. Therefore, in order to prevent a malfunction in starting the compressor due to the differential pressure between the high-pressure side and the low-pressure side of the compressor, control is performed to wait for the operation of the compressor until the differential pressure between the high-pressure side and the low-pressure side of the compressor is reduced (until a pressure equalization state is reached).

[0004] For example, in an air conditioner having a pressure sensor, since the differential pressure between the high-pressure side and the low-pressure side of the compressor can be directly detected, the operation waiting time of the compressor is the shortest time required for pressure equalization.

[0005] On the other hand, particularly in a portable air conditioner, many do not have a pressure sensor in order to make the device smaller, lighter, and less costly. In such a device, a configuration for indirectly detecting the pressure equalization state is adopted. For example, it is known that pressure equalization is assumed based on the passage of time after turning off the power of the air conditioner (stopping the operation of the compressor) (see, for example, Patent Document 1).

[0006] In the apparatus described in Patent Document 1, a restart prevention timer is provided, and during the time set by the timer, the differential pressure between the high-pressure and low-pressure sides of the compressor is reduced to below the target differential pressure. In other words, the time required for pressure equalization is ensured by the time set by the restart prevention timer.

[0007] Japanese Patent Publication No. 2018-025333

[0008] However, in configurations that assume pressure equalization over time, it is necessary to ensure a sufficient amount of time for pressure equalization to occur, which presents a problem of poor user convenience.

[0009] Specifically, for example, when the power is turned on (a request to drive the compressor is received), assuming that a pressure difference exists between the high-pressure and low-pressure sides of the compressor, the compressor cannot start driving (operating) until a sufficient amount of time has elapsed for the compressor to reach a preset equal pressure state. In particular, with portable air conditioning units (so-called spot coolers), it is expected that users will frequently change the location of the air conditioning unit (move it) for use. In such cases, it is desirable to deliver cool air in a short time after the power is turned on (re-)on, but in reality, even if the pressure difference has decreased to a level where the compressor can start operating, it cannot start until a predetermined amount of time has elapsed (resulting in a long waiting time), which can be inconvenient for the user.

[0010] The present invention has been made in view of the above problems, and provides an air conditioning system that can shorten the waiting time until the compressor can be started, even in a mobile air conditioning system that does not have a pressure detection means, thereby improving user convenience.

[0011] The present invention relates to a portable air conditioning system that houses a refrigerant circuit and a control unit, which include a compressor, a condenser, a pressure reducing device, and an evaporator, within a housing, and is characterized by comprising a temperature sensor for detecting the temperature of air that has exchanged heat with the condenser, and a start determination unit that determines whether or not to start the compressor based on the temperature information from the temperature sensor when a request to start the compressor is generated.

[0012] According to the present invention, even a mobile air conditioning system that does not have a pressure detection means can be provided that can shorten the waiting time until the compressor can be started, thereby improving user convenience.

[0013] This is a perspective view of an air conditioning system according to an embodiment of the present invention, viewed from the front at an angle. This is a perspective view of the air conditioning system viewed from the rear at an angle. This is a side view of the air conditioning system viewed from the other side in the width direction. This is a longitudinal cross-sectional view of the air conditioning system, taken along the line X-X in Figure 2. This is a block diagram showing the function of the air conditioning system. This is a flow diagram showing the start-up control of the compressor of the air conditioning system.

[0014] The following describes an air conditioning system 100 according to an embodiment of the present invention. The air conditioning system 100 of this embodiment is equipped with a user-side heat exchanger and a heat source-side heat exchanger, and is a portable, compact air conditioning system that can be used outdoors, for example, but its use, installation location, size, etc., are not particularly limited. The user-side heat exchanger becomes an evaporator when the air conditioning system 100 is in cooling operation and a condenser when it is in heating operation, and the heat source-side heat exchanger becomes a condenser when the air conditioning system 100 is in cooling operation and an evaporator when it is in heating operation. The air conditioning system 100 of this embodiment is capable of cooling operation and / or heating operation, but in the following embodiment, as an example of the air conditioning system 100, a device capable of cooling operation, such as a spot cooler, will be described.

[0015] <Overall Configuration> As shown in Figures 1 and 2, the air conditioning system 100 comprises a housing 1, and is a self-contained air conditioning system in which, for example, a user-side heat exchanger and a heat source-side heat exchanger are housed in the housing 1. The air conditioning system 100 is also a movable (or portable) air conditioning system 100 that can be moved and used outdoors, etc. Specifically, as shown in Figures 3 and 4, the air conditioning system 100 comprises a compressor 2, an evaporator 3, a condenser 4, an evaporator-side blower 5, a condenser-side blower 6, a pressure reducing device 7, and a control device (control unit) 8 housed in the housing 1, and also comprises refrigerant piping 9 that connects the compressor 2, condenser 4, evaporator 3, and pressure reducing device 7 to form a refrigerant flow path for circulating refrigerant between these components.

[0016] The compressor 2, condenser 4, pressure reducing device 7, evaporator 3, and refrigerant piping 9 constitute a refrigerant circuit in which the refrigerant circulates in the order of compressor 2, condenser 4, pressure reducing device 7, and evaporator 3. This refrigerant circuit has a branch pipe 20 that branches off from the refrigerant piping 9 and forms a refrigerant opening 20a into which refrigerant can be sealed into the refrigerant circuit from the outside.

[0017] <Housing> As shown in Figure 1, the housing 1 is a resin molded body constructed by molding, for example, a resin material. The housing 1 as a whole has a roughly rectangular parallelepiped shape and is composed of a main body 1a and a front panel 1b. The front side of the main body 1a in the front-to-back direction D1 is open, and the front panel 1b is provided to close this opening. The front panel 1b is also provided with an operation display unit 11, an air outlet 12, and an air intake 13. The operation display unit 11 is positioned in front of the control device 8 housed in the housing 1, and allows the control device 8 to be operated. The air outlet 12 is positioned in front of the evaporator 3 housed in the housing 1, and blows out air (cold air) that has passed through the evaporator 3. Furthermore, the air intake 13 is positioned in front of the condenser-side blower 6 housed in the housing 1, and draws air into the housing 1 toward the condenser 4.

[0018] As shown in Figure 2, an air intake port 14 and an exhaust port 15 are provided on the rear surface 1d of the housing 1, facing the rear in the front-to-back direction D1. The air intake port 14 is positioned behind the evaporator-side blower 5 housed in the housing 1, and is designed to draw air into the housing 1 towards the evaporator 3. The exhaust port 15 is positioned behind the condenser 4 housed in the housing 1, and is designed to blow out the air (exhaust) that has passed through the condenser 4.

[0019] <Condenser> As shown in Figure 4, the condenser 4 is located in the lower part of the housing 1. The condenser 4 is a fin-and-tube type heat exchanger in which multiple heat exchange fins 4x are arranged to extend in the front-to-back direction D1, and adjacent fins 4x are connected to each other by tubes extending in the up-to-down direction D2. Heat exchange takes place between the air and the refrigerant as air flows between these heat exchange fins 4x in the front-to-back direction D1. As shown by the dashed arrows in Figure 3, in this embodiment, air flows through the condenser 4 from the front to the rear in the front-to-back direction D1. The condenser 4 is housed in a condensing-side inner case 400 within the housing 1.

[0020] <Condenser-side blower> The condenser-side blower 6 is located inside the housing 1, in front of the condenser 4 in the front-to-back direction D1. The condenser-side blower 6 draws in air (outside air) from the air intake port 13 (see Figure 1) of the housing 1, circulates the air from front to rear through the air passage between the fins 4x in the condenser 4, and discharges the air that has exchanged heat with the condenser 4 from the exhaust port 15 (see Figure 2).

[0021] <Evaporator> The evaporator 3 is located above the condenser 4 within the housing 1. The evaporator 3 is a fin-and-tube type heat exchanger in which multiple heat exchange fins 3x are arranged to extend in the front-to-back direction D1, and adjacent fins 3x are connected to each other by tubes extending in the up-to-down direction D2. Heat exchange takes place between the air and the refrigerant by air flowing in the front-to-back direction D1 between these heat exchange fins 3x. As shown by the dashed arrows in Figure 3, in this embodiment, air flows through the evaporator 3 from the rear to the front. The evaporator 3 is housed in the evaporation-side inner case 300 within the housing 1.

[0022] The evaporator 3 is positioned above the condenser 4 within the housing 1, overlapping a portion of the upper surface 4a of the condenser 4. In order to ensure a sufficient heat exchange area in the condenser 4, the width D3 dimension of the condenser 4 is larger than the width D3 dimension of the evaporator 3.

[0023] Furthermore, the central position C3x in the width direction D3 of the evaporator 3 is offset to one side in the width direction D3 (the rear side in Figure 3) relative to the central position C4x in the width direction D3 of the condenser 4. Therefore, the evaporator 3 is positioned above the condenser 4 so as to overlap a portion of the upper surface 4a of the condenser 4. In this embodiment, the sides 3b and 4b of the evaporator 3 and condenser 4 facing one side in the width direction D3 (the rear side in Figure 3) are positioned at approximately the same location in the width direction D3. The space above the region of the upper surface 4a of the condenser 4 that does not overlap with the evaporator 3, and that is on the other side in the width direction D3 relative to the evaporator 3 (the front side in Figure 3), is defined as the non-overlapping space S.

[0024] Furthermore, as shown in Figure 4, the central position C3y in the front-to-back direction D1 in the evaporator 3 is offset forward relative to the central position C4y in the front-to-back direction D1 in the condenser 4 (see Figure 3).

[0025] Below the evaporator 3, a water receiving section 10 is provided to receive the drain water that condenses from moisture in the air and adheres to the evaporator 3. The water receiving section 10 forms the bottom of the evaporator-side inner case 300. The rear end of the water receiving section 10 is close to or in contact with the front surface 4c of the condenser 4, and is configured to circulate the drain water collected from the evaporator 3 toward the front surface 4c of the condenser 4 in order to cool the condenser 4 for the purpose of improving cooling capacity.

[0026] <Evaporator-side blower> The evaporator-side blower 5 is located inside the housing 1, behind the evaporator 3 in the front-to-back direction D1. The evaporator-side blower 5 draws in air (outside air) from the air intake port 14 (see Figure 2), circulates the air from the rear to the front through the air passage between the fins 3x in the evaporator 3, and blows out the air (cold air) that has exchanged heat with the evaporator 3 from the air outlet port 12 (see Figure 1).

[0027] <Depressurization Device> Returning to Figure 3, the depressurization device 7 is a device that depressurizes and expands the refrigerant, and in this embodiment it is composed of a capillary tube. The depressurization device 7 is located in a non-overlapping space S within the housing 1. That is, the depressurization device 7 is located on the other side of the width direction D3 relative to the evaporator 3 (the side shown in Figure 3 that is closer to the viewer).

[0028] <Control device> The control device 8 has a circuit board on which various electronic components, including an inverter, are mounted. For example, it controls the rotational speed of the motor that drives the compressor 2 by converting and outputting the voltage and frequency of the power supplied from the power source. The control device 8 also receives signals input to the operation display unit 11 (see Figure 1) of the housing 1 and controls the refrigerant circuit according to the received signals. In this embodiment, the control device 8 is positioned on one side of the width direction D3 (the rear side shown in Figure 3) opposite to the non-overlapping space S in the width direction D3 relative to the evaporator 3.

[0029] <Compressor> The compressor 2 is a device for compressing the refrigerant and is located within the housing 1 on one side in the width direction D3 relative to the condenser 4 (the rear side shown in Figure 3) and below the control device 8. In this embodiment, the compressor 2 is located adjacent to the condenser 4 in the width direction D3 at a position closer to the front of the condenser 4. An accumulator (not shown) for separating the gas and liquid of the refrigerant is located in front of the compressor 2.

[0030] <Refrigerant Piping> As shown in Figures 3 and 4, the refrigerant piping 9 includes a first pipe 9a connecting the compressor 2 and the condenser 4, a second pipe (pressure / condensation connecting pipe) 9b connecting the condenser 4 and the pressure reducing device 7, a third pipe 9c connecting the pressure reducing device 7 and the evaporator 3, and a fourth pipe 9d connecting the evaporator 3 and the compressor 2.

[0031] The first pipe 9a extends upward from the compressor 2 and then along the upper surface 4a of the condenser 4 toward the other side in the width direction D3 (the front side in Figure 3), and is connected to the condenser 4 at a condenser inlet 41 formed in the condenser-side inner case 400 at a position near the rear of the condenser 4, which opens into a non-overlapping space S and toward one side in the width direction D3 (the rear side in Figure 3).

[0032] The second pipe 9b is positioned in front of the condenser inlet 41 and extends upward from the condenser outlet 42, which is formed in the condenser-side inner case 400 and opens upward into a non-overlapping space S. After that, it extends forward via a bend 9x and is connected to the pressure reducing device 7. In other words, the second pipe 9b is positioned adjacent to the pressure reducing device 7 and behind the pressure reducing device 7.

[0033] The third pipe 9c extends upward from the pressure reducing device 7 and is connected to the evaporator 3 at an evaporator inlet 31 formed on the upper surface of the evaporator-side inner case 300 at a position near the front of the evaporator 3, which opens to the other side in the width direction D3 (the front side shown in Figure 3).

[0034] The fourth pipe 9d extends from the evaporator outlet 32, which is formed on the upper surface of the evaporator-side inner case 300 behind the evaporator inlet 31 and opens to one side in the width direction D3 (the rear side in Figure 3), along the upper surface 3a of the evaporator 3 to one side in the width direction D3 (the rear side in Figure 3), then extends downward along the side of the evaporator 3 and condenser 4 facing one side in the width direction D3 (the rear side in Figure 3), passes through the accumulator 2x, and is connected to the compressor 2.

[0035] In this configuration, the refrigerant is compressed by the compressor 2 through the refrigerant piping 9, becoming high temperature and high pressure. It then flows into the condenser 4 through the first pipe 9a, becoming low temperature and high pressure. Subsequently, the refrigerant flows into the pressure reducing device 7 through the second pipe 9b, where it is depressurized to a low temperature and low pressure state. It then flows into the evaporator 3 through the third pipe 9c, where it evaporates and becomes high temperature and low pressure. Finally, it flows back into the compressor 2 through the fourth pipe 9d, where it is compressed again to a high temperature and high pressure state. By repeating this refrigeration cycle, the air conditioning system 100 performs cooling operation.

[0036] <Branch Pipe> The branch pipe 20 branches off from the second pipe 9b at a bend 9x midway along the second pipe 9b and extends upward along the side facing the other side (the front side in Figure 3) in the width direction D3 of the evaporator 3. In this embodiment, the branch pipe 20 extends straight upward from the condenser outlet 42 in a direction perpendicular to the upper surface 4a of the condenser 4. Therefore, the branch pipe 20 is located in the non-overlapping space S. The refrigerant opening 20a formed in the branch pipe 20 opens upward at the upper end of the branch pipe 20. The upper end of the branch pipe 20 is located below the upper surface 3a of the evaporator 3. Therefore, the refrigerant opening 20a is also located below the upper surface 3a of the evaporator 3 and opens into the non-overlapping space S. The refrigerant opening 20a is used to seal refrigerant into the refrigerant circuit, but it may also be used for other purposes, such as extracting refrigerant from the refrigerant circuit.

[0037] <Compressor Startup Control> Figure 5 is a block diagram showing an example of the functions of the air conditioning system 100. The control device (control unit) 8 is composed of a microcomputer including a microprocessor, and comprehensively controls the operation of each component so that the air conditioning system 100 can realize various functions. One of the functions of the air conditioning system 100 is the startup control of the compressor 2. Figure 5 shows an example of the control unit 8 that performs the startup control of the compressor 2. As shown in Figure 5, the control unit 8 has an evaporator blower control unit 81 that controls the evaporator-side blower 5, a condenser blower control unit 82 that controls the condenser-side blower 6, and a startup determination unit 83, and performs the startup control of the compressor.

[0038] The control unit 8 is connected to the first temperature sensor 201, the second temperature sensor 202, and the third temperature sensor 203, and the temperature information detected by these sensors is input to the control unit 8. The control unit 8 is also connected to the compressor 2, evaporator 3, condenser 4, evaporator-side blower 5, and condenser-side blower 6, and the control unit 8 controls these components comprehensively.

[0039] The temperature sensor 200 includes, for example, a first temperature sensor 201, a second temperature sensor 202, and a third temperature sensor 203. The first temperature sensor 201 is an exhaust temperature (exhaust heat temperature) sensor installed near the exhaust port 15 (for example, between the condenser 4 and the exhaust port 15) and detects the temperature of the air (exhaust) that has exchanged heat with the condenser 4.

[0040] The second temperature sensor 202 is provided near the air intake 13 and is a sensor for detecting the outside air temperature. For example, the second temperature sensor 202 is provided between the air intake 13 and the condenser 4 and is an intake temperature sensor for detecting the temperature of the air (outside air) sucked from the air intake 13.

[0041] The third temperature sensor 203 is provided near the air outlet 12 and is a sensor for detecting the temperature of the air (cold air) that has exchanged heat with the evaporator 3. For example, the third temperature sensor 203 is a blow-out temperature sensor provided between the evaporator 3 and the air outlet 12.

[0042] When a start-up request for the compressor 2 occurs, the start-up determination unit 83 of the control unit 8 determines whether the compressor 2 can be started based on the temperature information detected by the temperature sensor 200.

[0043] The start-up determination unit 83 estimates the differential pressure between the high-pressure side and the low-pressure side of the compressor 2 based on at least the temperature information acquired by the first temperature sensor 201, that is, the temperature of the air (exhaust temperature) that has exchanged heat with the condenser 4. When there is still a differential pressure in the refrigerant circuit (the high-pressure side and the low-pressure side of the compressor 2), the temperature of the air that exchanges heat with the condenser 4, which becomes the high-pressure side of the refrigerant circuit, also becomes high. Therefore, by detecting the temperature (exhaust temperature) of the air, the differential pressure of the compressor 2 can be estimated based on the exhaust temperature.

[0044] When the start-up determination unit 83 estimates that the differential pressure between the high-pressure side and the low-pressure side of the compressor 2 is equal to or greater than a predetermined value based on the determination temperature based on the exhaust temperature, it determines that the refrigerant circuit is not equalized and there may be a state where a start-up failure of the compressor 2 occurs, and prohibits the start-up of the compressor 2. On the other hand, when it is estimated that the differential pressure between the high-pressure side and the low-pressure side of the compressor 2 is less than the predetermined value based on the exhaust temperature, it determines that the equalization state has been shifted to and permits the start-up of the compressor 2.

[0045] More specifically, the startup determination unit 83 determines whether or not to start the compressor 2 based on a determination temperature derived from, for example, the first temperature information (exhaust temperature) acquired by the first temperature sensor 201 and the second temperature information acquired by the second temperature sensor 202. Specifically, the startup determination unit 83 acquires temperature information of the air discharged from the exhaust port 15 (exhaust temperature, first temperature information) and temperature information of the air drawn in from the air intake port 13 (outside air temperature, second temperature information), and calculates the difference between these (exhaust temperature - outside air temperature). This temperature difference ΔT (hereinafter referred to as "exhaust outside air temperature difference") is then used as the determination temperature, and if the determination temperature is above a predetermined determination threshold (for example, 3°C), it is estimated that the pressure is not equalized, and the startup of the compressor 2 is not permitted. On the other hand, if it is below the determination threshold, it is estimated that the pressure is equalized, and the startup of the compressor 2 is permitted.

[0046] Furthermore, when a request to start the compressor 2 is received, the control unit 8 preemptively lowers the temperature of the condenser 4, which is on the high-pressure side of the refrigerant circuit, (bringing it closer to the ambient temperature) before starting the compressor 2. Specifically, the condenser blower control unit 82 starts the condenser-side blower 6 and draws air (outside air) into the housing 1 from the air intake port 13. Hereinafter, when the compressor 2 is stopped and a request to start the compressor 2 is received, starting the condenser-side blower 6 before starting the compressor 2 is referred to as "pre-condenser blowing".

[0047] The condenser blower control unit 82 sets the airflow rate of the condenser-side blower 6 to a predetermined value or higher when blowing air into the pre-condenser. More specifically, for example, it sets the airflow rate of the condenser-side blower 6 to a moderate airflow rate or higher during normal operation. In some cases, it also sets the airflow rate to near the maximum airflow rate. More specifically, if the airflow rate of the condenser-side blower 6 during normal operation can be set to, for example, three levels (small, medium, and large) (for example, if the operation display unit 11 has a setting switch with three levels: small, medium, and large for airflow setting), it sets the airflow rate for pre-condenser blowing to "medium" or higher.

[0048] Furthermore, if you want to lower the temperature of the condenser 4 quickly, it is desirable to set the airflow rate of the pre-condenser blower to near the maximum airflow rate (for example, airflow rate "high"). Also, if noise is a concern due to the capacity of the condenser-side blower 6, it is desirable to set the airflow rate of the pre-condenser blower to, for example, "medium".

[0049] Also, for example, the set value of the pre-condenser blower set by the condenser blower control unit 82 may be changed according to the exhaust outside air temperature difference ΔT. Specifically, in addition to the determination threshold value (first threshold value) for determining whether the compressor 2 can be started, a second threshold value for performing the air volume setting is provided. The second threshold value is set to a temperature (for example, 5°C) higher than the first threshold value (for example, 3°C). When the exhaust outside air temperature difference ΔT is higher than the second threshold value (for example, 6°C, etc.), prior to starting the compressor 2, the air volume of the pre-condenser blower is set to near the maximum air volume (for example, "large") and operated (the compressor 2 cannot be started). When it is below the second threshold value and above the first threshold value, the air volume of the pre-condenser blower may be set to be smaller (for example, "medium") and the operation may be changed.

[0050] Further, when a start request for the compressor 2 occurs, the control unit 8 raises the temperature of the evaporator 3 on the low-pressure side of the refrigerant circuit (brings it closer to the outside air temperature) prior to starting the compressor 2. That is, the evaporator blower control unit 81 starts the evaporator-side blower 5 and sucks air (outside air) into the housing 1 from the air suction port 14. Hereinafter, when a start request for the compressor 2 occurs while the compressor 2 is in a stopped state, starting the evaporator-side blower 5 prior to starting the compressor 2 is referred to as "pre-evaporator blowing".

[0051] The evaporator blower control unit 81 sets the air volume of the evaporator-side blower 5 to a predetermined value or more during pre-evaporator blowing. Specifically, for example, the air volume of the evaporator-side blower 5 is set to be at least medium during normal operation. Also, in some cases, the air volume is set to near the maximum air volume. More specifically, when the air volume of the evaporator-side blower 5 can be set in, for example, three steps (small, medium, large) (for example, when there are three-step setting switches for small, medium, and large air volume settings on the operation display unit 11), the air volume during pre-evaporator blowing is set to "medium" or more.

[0052] If the temperature of the evaporator 3 needs to be raised quickly, it is desirable to set the airflow rate in the pre-evaporator blower to near the maximum airflow rate (for example, airflow rate "high"). Also, if noise is a concern due to the capacity of the evaporator-side blower 5, it is desirable to set the airflow rate in the pre-evaporator blower to, for example, "medium". Furthermore, for example, the setting value of the pre-evaporator blower set by the evaporator blower control unit 81 may be changed based on the exhaust outside air temperature difference ΔT. Specifically, in addition to the determination threshold (first threshold) for determining whether or not the compressor 2 can be started, a second threshold for setting the airflow rate is provided. The second threshold is set to a temperature higher than the first threshold (e.g., 3°C) (e.g., 5°C). If the exhaust outside air temperature difference ΔT is higher than the second threshold (e.g., 6°C), the pre-evaporator airflow rate may be set to near the maximum airflow rate (e.g., "high") before starting the compressor 2 (compressor 2 cannot be started). If the temperature is below the second threshold but above the first threshold, the pre-evaporator airflow rate may be set to a lower value (e.g., "medium") and the system may be operated.

[0053] The airflow settings for the pre-condenser blower and the pre-evaporator blower may be the same or different. Furthermore, if a configuration allows for changing the airflow settings using a second threshold, this may be applied to both the pre-condenser blower and the pre-evaporator blower, or to only one of them.

[0054] Figure 6 is a flowchart showing an example of compressor 2 startup control performed by the control unit 8. Compressor 2 startup control is performed when the power to the air conditioning system 100 is turned on.

[0055] When the control unit 8 receives a request to start the compressor 2 (step S01), prior to starting the compressor 2, the condenser blower control unit 82 starts the condenser-side blower 6 and performs pre-condenser blowing (step S03). The condenser blower control unit 82 operates the condenser-side blower 6 to a predetermined airflow rate (for example, a moderate airflow rate or higher during normal operation). Also, prior to starting the compressor 2, the condenser blower control unit 82 starts the evaporator-side blower 5 and performs pre-evaporator blowing (step S05). The evaporator blower control unit 81 operates the evaporator-side blower 5 to a predetermined airflow rate (for example, a moderate airflow rate or higher during normal operation).

[0056] Subsequently, the control unit 8 reads the first temperature information (exhaust temperature) acquired by the first temperature sensor 201 and the second temperature information (outside air temperature) acquired by the second temperature sensor 202 (step S07).

[0057] The startup determination unit 83 calculates the exhaust outside air temperature difference ΔT (= exhaust temperature - outside air temperature) and compares it with a determination threshold (for example, 3°C). If the exhaust outside air temperature difference ΔT is greater than or equal to the determination threshold, it is estimated that the pressure is not equalized and the process returns to step S07. On the other hand, if the exhaust outside air temperature difference ΔT is less than the determination threshold, it is estimated that the pressure is equalized and the process proceeds to step S11. Note that the determination threshold (3°C) is just an example and is not limited to this value. The determination threshold is set appropriately by obtaining in advance, through tests or other means, the exhaust outside air temperature difference ΔT when the refrigerant circuit is actually in an equalized pressure state, according to the capacity of each component of the air conditioning system 100.

[0058] The control unit 8 starts the compressor 2 (step S11) and terminates the process when the start determination unit 83 estimates that the pressure is equalized.

[0059] The order of steps S03 and S05 can be reversed, but starting the condenser-side blower 6 first allows for a more rapid reduction in the temperature of the condenser 4 (promoting heat dissipation).

[0060] Conventionally, in air conditioning systems without pressure sensors, it was necessary to ensure sufficient time for the refrigerant circuit to reliably reach an equal pressure state after the power to the air conditioning system was cut off, in order to avoid compressor startup failure due to differential pressure in the refrigerant circuit. In other words, even if the differential pressure actually decreased and the pressure equalized after the power was turned on, there were many cases where the compressor could not be started until a longer time had passed. In particular, with mobile air conditioning systems 100, for example, it is often desirable to cut off the power when moving and then turn on the power after moving to start air conditioning immediately. Conventionally, even when the compressor was actually ready to start, a long waiting time was required, which was inconvenient for the user.

[0061] In this embodiment, in the mobile air conditioning unit 100, the compressor 2 is started based on first temperature information (exhaust temperature) acquired by a first temperature sensor 201 that detects the temperature of the air that has exchanged heat with the condenser 4. In other words, since the decision on whether or not to start the compressor 2 is made based on the actual exhaust temperature, it is no longer necessary to wait for the compressor 2 to start for an unnecessarily long time as in the conventional method, and the time from when the air conditioning unit 100 is powered on (when the air conditioning unit 100 was last powered off) to when the compressor 2 is started (waiting time) can be shortened. In particular, in the case of mobile air conditioning units 100, it is often assumed that the power will be turned back on a short time after the power is cut off, but even in such cases the waiting time can be shortened, thus improving user convenience.

[0062] Furthermore, the air conditioning system 100 starts the compressor 2 when it is estimated that the pressure is equalized based on the exhaust temperature. In other words, since the compressor 2 can be started when it is estimated that the pressure is equalized, it is no longer necessary to wait for an unnecessarily long time as in the conventional system, the load on the compressor 2 can be suppressed by the differential pressure, and damage to the compressor 2 can be prevented.

[0063] Furthermore, since the equal pressure state of the refrigerant circuit can be estimated without using a pressure sensor, the number of parts in the air conditioning unit 100 can be reduced, contributing to cost reduction. In addition, even in an air conditioning unit 100 that does not have a pressure sensor, the load on the compressor 2 can be suppressed by differential pressure, preventing damage to the compressor 2.

[0064] Furthermore, when a request is made to start the compressor 2, the condenser-side blower 6 is started prior to the start of the compressor 2, which allows the temperature of the condenser 4 to be reduced earlier. This also contributes to shortening the waiting time until the compressor 2 is started.

[0065] Furthermore, the air conditioning unit 100 is equipped with a first temperature sensor for detecting exhaust temperature and a second temperature sensor for detecting outside air temperature, and starts the compressor 2 when it is estimated that the pressure is equal based on the exhaust temperature and outside air temperature. In other words, since the compressor 2 can be started when it is estimated that the pressure is equal, it eliminates the need to wait for unnecessarily long periods of time as in the past, and the waiting time until the compressor 2 is started can be shortened, thereby improving user convenience.

[0066] Furthermore, based on the exhaust temperature (high pressure side) and the ambient temperature (low pressure side) of the refrigerant circuit, if the difference between the exhaust temperature and the ambient temperature is less than a predetermined value, it is estimated that the pressure is equalized, and the compressor 2 is permitted to start. Therefore, even in a configuration without a pressure sensor, accurate estimation is possible. Consequently, failures to start or damage to the compressor 2 can be avoided, and the waiting time from power-on to the start of the compressor 2 can be reduced compared to conventional systems.

[0067] Furthermore, when a request is made to start the compressor 2, the condenser-side blower 6 and the evaporator-side blower 5 are started prior to the start of the compressor 2, allowing the temperatures of the condenser 4 and evaporator 3 to approach the ambient temperature more quickly. As a result, a pressure equalization state can be achieved sooner, which also contributes to shortening the waiting time until the compressor 2 is started.

[0068] Furthermore, when the condenser-side blower 6 is operated while the compressor 2 is stopped (pre-condenser blowing is performed), the airflow rate of the condenser-side blower 6 is set to a predetermined value or higher, which allows the temperature of the condenser 4 to be lowered more quickly.

[0069] Furthermore, when the condenser-side blower 6 is operated while the compressor 2 is stopped (pre-condenser blowing is performed), the airflow rate of the condenser-side blower 6 is set to near the maximum airflow rate, which allows the temperature of the condenser 4 to be lowered more quickly.

[0070] In the above embodiment, the case where the determination temperature is the difference in exhaust outside air temperature ΔT was described, but the determination temperature is not limited to this. The startup determination unit 83 may, for example, determine whether or not to start the compressor 2 based on the determination temperature derived from the first temperature information (exhaust temperature) acquired by the first temperature sensor 201 and the third temperature information acquired by the third temperature sensor 203. Specifically, the startup determination unit 83 acquires the exhaust temperature (first temperature information) and the temperature information of the air blown out from the air outlet 12 (outlet temperature, third temperature information), and calculates the difference between them (exhaust temperature - outlet temperature). The determination temperature is then set to this temperature difference ΔT1 (hereinafter referred to as "exhaust outlet temperature difference"), and if the determination temperature is equal to or greater than a predetermined determination threshold (for example, 10°C), it is estimated that the pressure is not equalized, and the startup of the compressor 2 is not permitted. On the other hand, if it is less than the determination threshold, it is estimated that the pressure is equalized, and the startup of the compressor 2 is permitted. In this case, the processing flow is the same as in Figure 6, except that the temperature read in step S07 is replaced with the first temperature information and the third temperature information, and the judgment threshold in step S09 becomes a temperature higher than the exhaust outside air temperature difference ΔT. Therefore, no explanation is needed.

[0071] Alternatively, the determination temperature may be the temperature change of the condenser 4 over a predetermined period of time. For example, when a request to start the compressor 2 is generated, the start determination unit 83 reads the exhaust temperature acquired by the first temperature sensor 201 multiple times at predetermined intervals (e.g., every second) and calculates the amount of temperature change per unit time from the previous exhaust temperature. In this case, the interval for acquiring the exhaust temperature is sufficiently shorter than the conventional waiting time (e.g., about 90 seconds). Furthermore, when the amount of temperature change becomes small (approaches zero), it may be estimated that the system has reached an equal pressure state. Specifically, the compressor 2 is not started until the amount of temperature change falls below a predetermined determination threshold for determining whether or not to start the compressor 2, and the start of the compressor 2 is permitted when it falls below the determination threshold.

[0072] In this case, the determination may be made based on the temperature difference between the exhaust temperature initially read (initial value) and the latest exhaust temperature, rather than the change in temperature over time. The compressor 2 will not be started until this temperature difference falls below a predetermined threshold, and the compressor 2 will be allowed to start once it falls below the threshold.

[0073] As stated above, the present invention is not limited to the embodiments described, and various modifications can be made without departing from the spirit of the invention. For example, the present invention is not limited to an air conditioning device 100 that performs cooling operation such as a spot cooler, but may also be an air conditioning device 100 that is capable of heating operation, or an air conditioning device that can switch between cooling operation and heating operation, and the same effects can be obtained.

[0074] 1. Enclosure 1a. Main body 1b. Front panel 1d. Rear 2. Compressor 3. Evaporator 4. Condenser 5. Evaporator-side blower 6. Condenser-side blower 7. Pressure reducing device 8. Control device (control unit) 9. Refrigerant piping 10. Water receiving section 12. Air outlet 13. Air intake 14. Air intake 81. Evaporator blower control unit 82. Condenser blower control unit 83. Startup determination unit 100. Air conditioning system 200. Temperature sensors 201. First temperature sensor 202. Second temperature sensor 203. Third temperature sensor

Claims

1. A portable air conditioning system comprising a refrigerant circuit and control unit, each containing a compressor, condenser, pressure reducing device, and evaporator, wherein the system includes a temperature sensor for detecting the temperature of air that has undergone heat exchange with the condenser, and a start determination unit for determining whether or not to start the compressor based on the temperature information from the temperature sensor when a request to start the compressor is generated.

2. The air conditioning system according to claim 1, characterized in that the startup determination unit permits the startup of the compressor when it determines, based on the temperature information, that the differential pressure between the high-pressure side and the low-pressure side of the compressor is less than a predetermined value.

3. The air conditioning system according to claim 1, further comprising a condenser-side blower for supplying air to the condenser, wherein the control unit controls the condenser-side blower when a request to start the compressor occurs.

4. The air conditioning system according to claim 1, further comprising another temperature sensor for detecting ambient temperature, wherein the startup determination unit determines whether or not the compressor can be started based on the temperature information (hereinafter referred to as "first temperature information") and the temperature information from the other temperature sensor (hereinafter referred to as "second temperature information").

5. The air conditioning system according to claim 4, characterized in that the startup determination unit permits the startup of the compressor when the difference between the first temperature information and the second temperature information is less than a predetermined value.

6. The air conditioning system according to claim 4, comprising a condenser-side blower for supplying air to the condenser and an evaporator-side blower for supplying air to the evaporator, wherein the control unit operates the condenser-side blower and the evaporator-side blower prior to starting the compressor, and the start determination unit prevents the compressor from starting if the difference between the first temperature information and the second temperature information is greater than or equal to a predetermined value.

7. When the condenser-side blower is operated while the compressor is stopped, the control unit sets the airflow rate of the condenser-side blower to a predetermined value or higher, characterized in that the air conditioning system according to claim 3 or 6.

8. The air conditioning system according to claim 7, characterized in that the control unit sets the airflow rate of the condenser-side blower to near the maximum airflow rate.

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