air conditioning unit

Abstract

This invention provides an air conditioning system that can improve user convenience by reducing the waiting time until the compressor can be started, even for mobile air conditioning systems that do not have a means of detecting pressure. [Solution] The mobile air conditioning unit 100 houses a refrigerant circuit and control unit 8, which include a compressor 2, a condenser 4, a pressure reducing device 7, and an evaporator 3, in a housing 1. It also includes a first temperature sensor 201 for detecting the temperature of the air that has exchanged heat with the condenser 4, and a start determination unit 83 that determines whether or not to start the compressor 2 based on the temperature information from the first temperature sensor 201 when a request to start the compressor 2 is generated.

Description

Technical Field

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

Background Art

[0002] Conventionally, an air conditioner is known in which a compressor, a condenser, a decompressor, and an evaporator are annularly connected by a refrigerant pipe, and heat exchange as heating is performed in the condenser while controlling the pressure of the refrigerant with the compressor and the decompressor, and heat exchange as 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 casing 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 the occurrence of poor startup of 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 reduce the size and weight of the device and to reduce costs. 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 setting time of the restart prevention timer. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2018-025333 [Overview of the project] [Problems that the invention aims to solve]

[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 predetermined equalized pressure state to be reached. 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 state 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 unpleasant 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. [Means for solving the problem]

[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. [Effects of the Invention]

[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. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view of an air conditioning system according to an embodiment of the present invention, viewed from a diagonal front angle. [Figure 2] This is a perspective view of the above air conditioning unit, taken from a diagonal rearward angle. [Figure 3] This is a side view of the above air conditioning unit, seen from the other side in the width direction. [Figure 4] The above is a longitudinal cross-sectional view of the air conditioning system, specifically the XX cross-section in Figure 2. [Figure 5] This is a block diagram showing the functions of the above-mentioned air conditioning system. [Figure 6] This is a flowchart showing the start-up control of the compressor in the above-mentioned air conditioning system. [Modes for carrying out the invention]

[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 Structure> 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] <Enclosure> As shown in FIG. 1, the housing 1 is a resin molded body formed by molding a resin material, for example. The housing 1 has a substantially rectangular parallelepiped shape as a whole and is composed of a main body portion 1a and a front panel 1b. The front side in the front-rear direction D1 of the main body portion 1a is an opening, and the front panel 1b is provided so as to close this opening. Further, an operation display unit 11, an air outlet 12, and an air inlet 13 are provided on the front panel 1b. The operation display unit 11 is provided so as to be located in front of the control device 8 housed in the housing 1 and enables the control device 8 to be operated. The air outlet 12 is provided so as to be located in front of the evaporator 3 housed in the housing 1 and blows out the air (cold air) that has passed through the evaporator 3. Further, the air inlet 13 is provided so as to be located in front of the condenser side blower 6 housed in the housing 1 and takes air into the housing 1 toward the condenser 4.

[0018] Also, as shown in FIG. 2, an air inlet 14 and an exhaust port 15 are provided on the rear surface 1d facing the rear side in the front-rear direction D1 of the housing 1. The air inlet 14 is provided so as to be located behind the evaporator side blower 5 housed in the housing 1 and takes air into the housing 1 toward the evaporator 3. The exhaust port 15 is provided so as to be located behind the condenser 4 housed in the housing 1 and blows out the air (exhaust air) that has passed through the condenser 4.

[0019] <Condenser> As shown in FIG. 4, the condenser 4 is arranged at the lower part in the housing 1. The condenser 4 is a fin-and-tube type heat exchanger in which a plurality of heat exchange fins 4x are arranged so as to extend in the front-rear direction D1 and adjacent fins 4x are connected to each other by tubes extending in the vertical direction D2. Then, by allowing air to flow in the front-rear direction D1 between these heat exchange fins 4x, heat exchange is performed between the air and the refrigerant. In this embodiment, as shown by the broken line arrow in FIG. 3, air flows through the condenser 4 from the front side to the rear side in the front-rear direction D1. The condenser 4 is housed in a condensation side inner case 400 in the housing 1.

[0020] <Condenser-side blower> The condenser-side blower 6 is provided in front of the condenser 4 in the front-rear direction D1 within the housing 1. The condenser-side blower 6 sucks in air (outside air) from the air intake port 13 (see FIG. 1) of the housing 1, allows the air to flow from the front side to the rear side through the air flow path between the fins 4x of the condenser 4, and discharges the air that has exchanged heat with the condenser 4 from the exhaust port 15 (see FIG. 2).

[0021] <Evaporator> The evaporator 3 is disposed above the condenser 4 within the housing 1. The evaporator 3 is a fin-and-tube type heat exchanger in which a plurality of heat exchange fins 3x are arranged so as to extend in the front-rear direction D1 and adjacent fins 3x are connected to each other by tubes extending in the vertical direction D2. And heat exchange is carried out between the air and the refrigerant by allowing air to flow in the front-rear direction D1 between these heat exchange fins 3x. In this embodiment, as shown by the dashed arrow in FIG. 3, air flows through the evaporator 3 from the rear side toward the front side. The evaporator 3 is housed in the evaporation-side inner case 300 within the housing 1.

[0022] The evaporator 3 is disposed above the condenser 4 so as to overlap a part of the upper surface 4a of the condenser 4 within the housing 1. In order to secure the heat exchange area of the condenser 4, the dimension of the condenser 4 in the width direction D3 is larger than the dimension of the evaporator 3 in the width direction D3.

[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 rear to 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 pressure reducing device 7 is a device that reduces the pressure of the refrigerant and causes it to expand, and in this embodiment, it is composed of a capillary tube. The pressure reducing device 7 is located in a non-overlapping space S within the housing 1. That is, the pressure reducing 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 condensing-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 unit (control section) 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 start control of the compressor 2. Figure 5 shows an example of the control section 8 that performs the start control of the compressor 2. As shown in Figure 5, the control section 8 has an evaporator blower control section 81 that controls the evaporator-side blower 5, a condenser blower control section 82 that controls the condenser-side blower 6, and a start determination section 83, and performs the start 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 located near the air intake port 13 and is a sensor that detects the outside temperature. The second temperature sensor 202 is, for example, located between the air intake port 13 and the condenser 4 and is an intake temperature sensor that detects the temperature of the air (outside air) drawn in from the air intake port 13.

[0041] The third temperature sensor 203 is located near the air outlet 12 and detects the temperature of the air (cold air) that has undergone heat exchange with the evaporator 3. The third temperature sensor 203 is, for example, an outlet temperature sensor located between the evaporator 3 and the air outlet 12.

[0042] When a request to start the compressor 2 is received, the start determination unit 83 of the control unit 8 determines whether or not to start the compressor 2 based on the temperature information detected by the temperature sensor 200.

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

[0044] The startup determination unit 83 determines, based on the exhaust temperature, that if the differential pressure between the high-pressure and low-pressure sides of the compressor 2 is estimated to be above a predetermined value, the refrigerant circuit is not pressure-equalized and there is a possibility of a compressor 2 startup failure, and therefore the compressor 2 cannot be started. On the other hand, if the differential pressure between the high-pressure and low-pressure sides of the compressor 2 is estimated to be below a predetermined value based on the exhaust temperature, the unit determines that the system has transitioned to a pressure-equalized state and permits the compressor 2 to start.

[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 airflow 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 airflow".

[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 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, large) (for example, if the operation display unit 11 has a setting switch with three levels: small, medium, and large for airflow setting), the airflow rate for pre-condenser blowing is set 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] Furthermore, for example, the setting value of the pre-condenser airflow set by the condenser airflow control unit 82 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), and if the exhaust outside air temperature difference ΔT is higher than the second threshold (e.g., 6°C), the airflow rate of the pre-condenser airflow is set to near the maximum airflow rate (e.g., "high") prior to starting the compressor 2 (compressor 2 cannot be started). If the airflow rate is below the second threshold but above the first threshold, the airflow rate of the pre-condenser airflow may be changed to a smaller value (e.g., "medium") and the system may be operated.

[0050] Furthermore, when a request to start the compressor 2 is received, the control unit 8 raises the temperature of the evaporator 3, which is on the low-pressure side of the refrigerant circuit, to an early stage (bringing it closer to the ambient temperature) prior to starting the compressor 2. That is, the evaporator blower control unit 81 starts the evaporator-side blower 5 and draws air (outside air) into the housing 1 from the air intake port 14. Hereinafter, when the compressor 2 is stopped and a request to start the compressor 2 is received, 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 airflow rate of the evaporator-side blower 5 to a predetermined value or higher when blowing air into the pre-evaporator. More specifically, for example, it sets the airflow rate of the evaporator-side blower 5 to a medium level or higher during normal operation. In some cases, it sets the airflow rate to near the maximum airflow rate. More specifically, if the airflow rate of the evaporator-side blower 5 can be set to, for example, three levels (small, medium, 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-evaporator blowing to "medium" or higher.

[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 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 reach a state of equal pressure 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 had actually decreased and reached a state of equal pressure after the power was turned on, it was often the case that the compressor could not be started until a longer time had passed. This was particularly problematic for mobile air conditioning systems 100, where it is often desirable to cut off the power when moving the system and then turn it back on 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 compressor 2, the condenser-side blower 6 is started prior to the start of compressor 2, thereby allowing the temperature of condenser 4 to be reduced earlier. This also contributes to shortening the waiting time until 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, startup failures and 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 compressor 2, the condenser-side blower 6 and the evaporator-side blower 5 are started prior to the start of compressor 2, allowing the temperatures of 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 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 of the condenser-side blower 6 is set to near the maximum airflow, 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 startup determination unit 83 then uses this temperature difference ΔT1 (hereinafter referred to as "exhaust outlet temperature difference") as the determination temperature, 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, the explanation is omitted.

[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 startup 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 pressure has equalized. Specifically, the startup of the compressor 2 is not permitted until the amount of temperature change falls below a predetermined determination threshold for determining whether or not to start the compressor 2, and the startup of the compressor 2 is permitted when it falls below the determination threshold.

[0072] In this case, instead of looking at the change in temperature, the determination may be made based on the temperature difference between the exhaust temperature initially read (initial value) and the latest exhaust temperature. 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. [Explanation of Symbols]

[0074] 1 cabinet 1a Main body 1b Front panel 1d back 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 airflow control unit 82 Condenser airflow control unit 83 Startup judgment part 100 Air conditioner 200 Temperature Sensor 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, A temperature sensor for detecting the temperature of the air that has undergone heat exchange with the condenser, The system includes a start determination unit that, when a request to start the compressor is generated, determines whether or not to start the compressor based on the temperature information from the temperature sensor. An air conditioning system characterized by the following features.

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

3. The condenser is equipped with a condenser-side blower that supplies air to the condenser, The control unit controls the condenser-side blower when a request to start the compressor is received. The air conditioning device according to feature 1.

4. Equipped with other temperature sensors that detect the outside temperature, 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"). The air conditioning device according to feature 1.

5. The startup determination unit permits the startup of the compressor if the difference between the first temperature information and the second temperature information is less than a predetermined value. The air conditioning device according to feature 4.

6. A condenser-side blower that supplies air to the condenser, The evaporator is equipped with an evaporator-side blower that supplies air to the evaporator, Prior to starting the compressor, the control unit operates the condenser-side blower and the evaporator-side blower. The startup 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. The air conditioning device according to feature 4.

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. The air conditioning device according to claim 3 or 6.

8. The control unit sets the airflow rate of the condenser-side blower to near the maximum airflow rate. The air conditioning device according to feature 7.

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