JP7762864B2 - air conditioner - Google Patents

Description

This disclosure relates to an air conditioner.

As described in Patent Document 1, air conditioners have been known that are composed of an indoor unit placed inside the room to be air-conditioned and an outdoor unit placed outside the room. This air conditioner is configured so that humidified outdoor air can be supplied from the outdoor unit to the indoor unit.

Japanese Patent Application Laid-Open No. 2001-91000

However, there is a need to reduce the load on air conditioner components.

Therefore, the objective of this disclosure is to provide an air conditioner that can reduce the load on the air conditioner's components.

In order to solve the above-mentioned problems, according to one aspect of the present invention,
An air conditioner comprising an indoor unit and an outdoor unit,
an absorbent material provided in the outdoor unit that absorbs moisture in the outdoor air;
a flow path through which outdoor air flows, the flow path passing through the absorbent material, connecting the outside of the room with the inside of the indoor unit;
a first heater and a second heater that heat the outdoor air upstream of the absorbent material in the flow path;
a control unit that controls on/off of the first heater and the second heater;
Equipped with
In the air conditioner, the control unit differentiates a first timing at which the first heater is switched on from a second timing at which the second heater is switched on.

This disclosure provides an air conditioner that can reduce the load on the air conditioner's components.

1 is a schematic diagram of an air conditioner according to an embodiment of the present disclosure; Schematic diagram of ventilation system Schematic diagram of the ventilation system during ventilation operation Schematic diagram of ventilation system during humidification operation Schematic diagram of ventilation system during dehumidification operation 1 is a schematic diagram of the first heater and the second heater and their surroundings; Schematic diagram showing control for suppressing inrush current Schematic diagram for explaining the characteristics of a PTC heater Schematic diagram illustrating the heater current flowing through the PTC heater in the negative characteristic region. Schematic diagram illustrating the heater current flowing through the PTC heater in the negative characteristic region. Schematic diagram illustrating the heater current flowing through a PTC heater in the positive characteristic region. Schematic illustrating relay control, fan speed control, heater current and heater temperature FIG. 10 is a schematic diagram illustrating relay control according to a first modified example.

One aspect of the present invention is an air conditioner comprising an indoor unit and an outdoor unit, and including: an absorbent material provided in the outdoor unit that absorbs moisture from outdoor air; a flow path through which outdoor air flows that passes through the absorbent material and connects the outdoors with the interior of the indoor unit; a first heater and a second heater that heat the outdoor air upstream of the absorbent material in the flow path; and a control unit that controls the on/off of the first heater and the second heater, wherein the control unit differentiates between a first timing for switching on the first heater and a second timing for switching on the second heater.

This aspect reduces the load on the components of the air conditioner.

For example, the air conditioner may further include a first relay that switches the first heater on and off, and a second relay that switches the second heater on and off, and the control unit may control the switching timing for switching the first relay and the second relay on and off, and shift the first timing from the second timing.

For example, the second timing may be the timing when a first waiting time has elapsed since the first timing.

For example, the first waiting time may be greater than or equal to 15 seconds and less than or equal to 45 seconds.

For example, the air conditioner may further include a common relay that controls the current flowing through the first relay and the second relay, and the control unit may switch the common relay on and off before switching the first relay and the second relay on and off.

For example, the air conditioner may further include a fan that generates a flow of outdoor air in the flow path toward the indoor unit, and the first heater and the second heater may each be a PTC (Positive Temperature Coefficient) heater.

For example, the control unit may control the fan before switching on the first heater and the second heater, and cool the first heater and the second heater by blowing air from the fan.

For example, the control unit may reduce the fan speed of the fan before the first timing and the second timing.

For example, the control unit may increase the fan speed of the fan after a second waiting time has elapsed from the second timing.

For example, the second waiting time may be greater than or equal to 15 seconds and less than or equal to 45 seconds.

For example, the control unit may reduce the fan speed before switching off at least one of the first heater and the second heater.

For example, the control unit may alternately switch on the first relay and the second relay.

One embodiment of the present disclosure will be described below with reference to the drawings.

Figure 1 is a schematic diagram of an air conditioner according to one embodiment of the present disclosure.

As shown in FIG. 1, the air conditioner 10 according to this embodiment has an indoor unit 20 arranged in the room Rin to be air-conditioned, and an outdoor unit 30 arranged in the outdoor Rout.

The indoor unit 20 is equipped with an indoor heat exchanger 22 that exchanges heat with the indoor air A1, and a fan 24 that draws the indoor air A1 into the indoor unit 20 and blows the indoor air A1 into the room Rin after heat exchange with the indoor heat exchanger 22.

The outdoor unit 30 is equipped with an outdoor heat exchanger 32 that exchanges heat with outdoor air A2, and a fan 34 that draws the outdoor air A2 into the outdoor unit 30 and blows the outdoor air A2 out to the outdoor Rout after heat exchange with the outdoor heat exchanger 32. The outdoor unit 30 also is equipped with a compressor 36, expansion valve 38, and four-way valve 40 that operate a refrigeration cycle with the indoor heat exchanger 22 and the outdoor heat exchanger 32.

The indoor heat exchanger 22, outdoor heat exchanger 32, compressor 36, expansion valve 38, and four-way valve 40 are each connected by refrigerant piping through which refrigerant flows. During cooling operation and dehumidification operation (weak cooling operation), the air conditioner 10 executes a refrigeration cycle in which refrigerant flows from the compressor 36 through the four-way valve 40, outdoor heat exchanger 32, expansion valve 38, and indoor heat exchanger 22 in that order, before returning to the compressor 36. During heating operation, the air conditioner 10 executes a refrigeration cycle in which refrigerant flows from the compressor 36 through the four-way valve 40, indoor heat exchanger 22, expansion valve 38, and outdoor heat exchanger 32 in that order, before returning to the compressor 36.

In addition to air conditioning operation using a refrigeration cycle, the air conditioner 10 also performs air conditioning operation that introduces outdoor air A3 into the room Rin. To achieve this, the air conditioner 10 has a ventilation device 50. The ventilation device 50 is provided in the outdoor unit 30.

Figure 2 is a schematic diagram of the ventilation system.

As shown in Figure 2, the ventilation device 50 has an absorbent material 52 inside through which outdoor air A3 and A4 pass.

The absorbent material 52 is a member through which air can pass and which collects moisture from the air passing through it or adds moisture to the air passing through it. In this embodiment, the absorbent material 52 is disk-shaped and rotates around a rotation center line C1 that passes through its center. The absorbent material 52 is rotationally driven by a motor 54.

The absorbent material 52 is preferably a polymeric adsorbent that adsorbs moisture from the air. Polymeric adsorbents are composed, for example, of cross-linked sodium polyacrylate. Compared to adsorbents such as silica gel and zeolite, polymeric adsorbents absorb a greater amount of moisture per volume, can desorb moisture at low heating temperatures, and can retain moisture for long periods of time.

The ventilation device 50 includes a first flow path P1 and a second flow path P2 through which outdoor air A3 and A4 flow, respectively, passing through the absorbent material 52. The first flow path P1 and the second flow path P2 pass through the absorbent material 52 at different positions.

The first flow path P1 is a flow path through which outdoor air A3 flows toward the indoor unit 20. The outdoor air A3 flowing through the first flow path P1 is supplied to the indoor unit 20 via the ventilation duct 56.

In this embodiment, the first flow path P1 includes multiple tributary flow paths P1a and P1b upstream of the absorbent material 52. Note that in this specification, "upstream" and "downstream" are used with respect to the air flow.

The multiple tributary channels P1a and P2a converge upstream of the absorbent material 52. Each of the multiple tributary channels P1a and P1b is provided with a first and second heater 58 and 60 that heats the outdoor air A3.

The first and second heaters 58, 60 may have the same heating capacity or different heating capacities. Furthermore, the first and second heaters 58, 60 are preferably PTC (Positive Temperature Coefficient) heaters, which increase electrical resistance as current flows and the temperature rises, thereby preventing excessive increases in heating temperature. In the case of a PTC heater, there is no need to monitor the heating temperature because the heater itself regulates the heating temperature within a certain temperature range.

A first fan 62 is provided in the first flow path P1 to generate a flow of outdoor air A3 toward the indoor unit 20. In this embodiment, the first fan 62 is positioned downstream of the absorbent material 52. When the first fan 62 is activated, outdoor air A3 flows from the outdoor air Rout into the first flow path P1 and passes through the absorbent material 52.

Furthermore, the first flow path P1 is provided with a damper device 64 that distributes the outdoor air A3 flowing through the first flow path P1 to the room Rin (i.e., the indoor unit 20) or the outdoor Rout. In this embodiment, the damper device 64 is located downstream of the first fan 62. The outdoor air A3 distributed to the indoor unit 20 by the damper device 64 enters the indoor unit 20 via the ventilation duct 56 and is blown out into the room Rin by the fan 24.

The second flow path P2 is a flow path through which outdoor air A4 flows. Unlike the outdoor air A3 flowing through the first flow path P1, the outdoor air A4 flowing through the second flow path P2 does not head toward the indoor unit 20. After passing through the absorbent material 52, the outdoor air A4 flowing through the second flow path P2 flows out to the outdoor area Rout.

A second fan 66 is provided in the first flow path P1 to generate a flow of outdoor air A4. In this embodiment, the second fan 66 is located downstream of the absorbent material 52. When the second fan 66 is activated, outdoor air A4 flows from the outdoor Rout into the second flow path P2, passes through the absorbent material 52, and then flows out to the outdoor Rout.

The ventilation device 50 selectively performs ventilation operation, humidification operation, and dehumidification operation by selectively using the absorbent material 52, motor 54, first heater 58, second heater 60, first fan 62, damper device 64, and second fan 66.

Figure 3 is a schematic diagram of the ventilation device during ventilation operation.

Ventilation operation is an air conditioning operation in which outdoor air A3 is supplied directly to the room Rin (i.e., the indoor unit 20) via the ventilation duct 56. As shown in FIG. 3, during ventilation operation, the motor 54 continues to rotate the absorbent material 52. The first heater 58 and the second heater 60 are OFF and do not heat the outdoor air A3. The first fan 62 is ON, causing outdoor air A3 to flow through the first flow path P1. The damper device 64 distributes the outdoor air A3 in the first flow path P1 to the indoor unit 20. The second fan 66 is OFF, causing no flow of outdoor air A4 to occur through the second flow path P2.

During this ventilation operation, outdoor air A3 flows into the first flow path P1 and passes through the absorbent material 52 without being heated by the first and second heaters 58, 60. After passing through the absorbent material 52, the outdoor air A3 is distributed to the indoor unit 20 by the damper device 64. After passing through the damper device 64 and reaching the indoor unit 20 via the ventilation duct 56, the outdoor air A3 is blown into the room Rin by the fan 24. Through this ventilation operation, the outdoor air A3 is supplied directly to the room Rin, ventilating the room Rin.

Figure 4 is a schematic diagram of the ventilation system during humidification operation.

Humidification operation is an air conditioning operation that humidifies outdoor air A3 and supplies the humidified outdoor air A3 to the room Rin (i.e., the indoor unit 20). As shown in Figure 4, during humidification operation, the motor 54 continues to rotate the absorbent material 52. The first heater 58 and the second heater 60 are ON and heat the outdoor air A3. The first fan 62 is ON, causing the outdoor air A3 to flow through the first flow path P1. The damper device 64 distributes the outdoor air A3 in the first flow path P1 to the indoor unit 20. The second fan 66 is ON, causing the outdoor air A4 to flow through the second flow path P2.

During this humidification operation, outdoor air A3 flows into the first flow path P1, is heated by the first and second heaters 58, 60, and passes through the absorbent material 52. At this time, the heated outdoor air A3 is able to remove a greater amount of moisture from the absorbent material 52 than when the outdoor air A3 is not heated. As a result, the outdoor air A3 carries a greater amount of moisture. The outdoor air A3, which has passed through the absorbent material 52 and carried a greater amount of moisture, is distributed to the indoor unit 20 by the damper device 64. The outdoor air A3, which has passed through the damper device 64 and reached the indoor unit 20 via the ventilation duct 56, is blown into the room Rin by the fan 24. During this humidification operation, outdoor air A3 carrying a greater amount of moisture is supplied to the room Rin, humidifying the room Rin.

In addition, by turning off either the first heater 58 or the second heater 60, the amount of moisture that the outdoor air A3 removes from the absorbent material 52 can be reduced, i.e., weak humidification operation can be performed with a low amount of humidification of the indoor air Rin.

As the heated outdoor air A3 removes moisture, the absorbent 52's water retention capacity decreases, i.e., the absorbent 52 dries out. When the absorbent 52 dries out, the outdoor air A3 flowing through the first flow path P1 cannot remove moisture from the absorbent 52. To address this, the absorbent 52 removes moisture from the outdoor air A4 flowing through the second flow path P2. This keeps the absorbent 52's water retention capacity approximately constant, allowing humidification operation to continue.

Figure 5 is a schematic diagram of the ventilation system during dehumidification operation.

Dehumidification operation is an air conditioning operation that dehumidifies outdoor air A3 and supplies the dehumidified outdoor air A3 to the room Rin (i.e., the indoor unit 20). As shown in Figure 5, during dehumidification operation, adsorption operation and regeneration operation are performed alternately.

Adsorption operation is an operation in which moisture contained in the outdoor air A3 is adsorbed onto the absorbent material 52, thereby dehumidifying the outdoor air A3. As shown in Figure 5, during adsorption operation, the motor 54 continues to rotate the absorbent material 52. The first heater 58 and the second heater 60 are OFF and do not heat the outdoor air A3. The first fan 62 is ON, causing the outdoor air A3 to flow through the first flow path P1. The damper device 64 distributes the outdoor air A3 in the first flow path P1 to the indoor unit 20. The second fan 66 is OFF, causing no flow of outdoor air A4 to occur through the second flow path P2.

During this adsorption operation, outdoor air A3 flows into the first flow path P1 and passes through the absorbent material 52 without being heated by the first and second heaters 58, 60. At this time, the moisture carried in the outdoor air A3 is adsorbed by the absorbent material 52. This reduces the amount of moisture carried by the outdoor air A3, i.e., the outdoor air A3 is dried. After passing through the absorbent material 52, the outdoor air A3 is distributed to the indoor unit 20 by the damper device 64. After passing through the damper device 64 and reaching the indoor unit 20 via the ventilation duct 56, the outdoor air A3 is blown into the room Rin by the fan 24. Through this adsorption operation, the dried outdoor air A3 is supplied to the room Rin, dehumidifying the room Rin.

As the adsorption operation continues, the amount of water retained by the absorbent material 52 continues to increase, resulting in a decrease in the absorbent material's 52 adsorption capacity for the moisture contained in the outdoor air A3. A regeneration operation is performed to regenerate the absorbent material 52 in order to restore its adsorption capacity.

During regeneration operation, the motor 54 continues to rotate the absorbent material 52. The first heater 58 and second heater 60 are ON and heat the outdoor air A3. The first fan 62 is ON, causing the outdoor air A3 to flow through the first flow path P1. The damper device 64 distributes the outdoor air A3 in the first flow path P1 to the outdoor Rout rather than to the indoor unit 20. The second fan 66 is OFF, causing no flow of outdoor air A4 to occur in the second flow path P2.

During this regeneration operation, outdoor air A3 flows into the first flow path P1, is heated by the first and second heaters 58, 60, and passes through the absorbent 52. At this time, the heated outdoor air A3 removes a large amount of moisture from the absorbent 52. As a result, the outdoor air A3 carries a large amount of moisture. At the same time, the moisture retention capacity of the absorbent 52 decreases, i.e., the absorbent 52 dries and its adsorption capacity is regenerated. The outdoor air A3 that passes through the absorbent 52 and carries a large amount of moisture is diverted by the damper device 64 to the outdoor Rout and discharged to the outdoor Rout. As a result, during regeneration in dehumidification operation, outdoor air A3 carrying a large amount of moisture due to the regeneration of the absorbent 52 is not supplied to the room Rin.

By alternating between adsorption and regeneration operations in this manner, the adsorption capacity of the absorbent material 52 is maintained, allowing dehumidification operation to be carried out continuously.

The air conditioning operations using the refrigeration cycle (cooling operation, dehumidifying operation (weak cooling operation), heating operation) and the air conditioning operations using the ventilation device 50 (ventilation operation, humidifying operation, dehumidifying operation) described above can be performed separately or simultaneously. For example, by simultaneously performing dehumidifying operation using the refrigeration cycle and dehumidifying operation using the ventilation device 50, it is possible to dehumidify the room Rin while maintaining a constant room temperature.

The air conditioning operation to be performed by the air conditioner 10 is selected by the user. For example, when the user performs a selection operation on the remote controller 70 shown in Figure 1, the air conditioner 10 performs the air conditioning operation corresponding to that operation.

Up to this point, we have provided an overview of the configuration and operation of the air conditioner 10 according to this embodiment. From here, we will explain further features of the air conditioner 10 according to this embodiment.

The structure for turning the first heater 58 and second heater 60 on and off will be explained.

Figure 6 is a schematic diagram of the first heater and the area around the second heater.

As shown in FIG. 6, the on/off of the first heater 58 and the second heater 60 is controlled by a common relay 80, a first relay 82, and a second relay 84. The common relay 80, the first relay 82, and the second relay 84 are also controlled by a control unit 90.

The common relay 80 controls the current flowing through the first relay 82 and the second relay 84.

In this embodiment, the common relay 80 is arranged in the current path EP. One end of the current path EP is connected to the power supply, and the other end of the current path EP is connected to the heaters 58 and 60. The other end of the current path EP branches into a first current path EP1 and a second current path EP2 connected to the first heater 58. The first current path EP1 includes the first heater 58 and a first relay 82. The second current path EP2 includes the second heater 60 and a second relay 84. The current paths EP, EP1, and EP2 are, for example, wiring.

When the common relay 80 is on, the current Ih can flow toward the first current path EP1 and the second current path EP2. On the other hand, when the common relay 80 is off, the current Ih does not flow toward the first current path EP1 and the second current path EP2.

When the common relay 80 is on, the first relay 82 switches the first heater 58 on and off. When the first relay 82 is on, the first heater 58 is on, and when the first relay 82 is off, the first heater 58 is off. Specifically, when the first relay 82 is on, current Ih flows from the common relay 80 through the first current path EP1 to the first heater 58. This causes the first heater 58 to be energized and turned on. On the other hand, when the first relay 82 is off, current Ih no longer flows from the common relay 80 to the first current path EP1. This causes the first heater 58 to stop being energized and turn off.

When the common relay 80 is on, the second relay 84 switches the second heater 60 on and off. When the second relay 84 is on, the second heater 60 is on, and when the second relay 84 is off, the second heater 60 is off. Specifically, when the second relay 84 is on, current Ih flows from the common relay 80 through the second current path EP2 to the second heater 60. This causes the second heater 60 to be energized and turned on. On the other hand, when the second relay 84 is off, current Ih no longer flows from the common relay 80 to the second current path EP2. This causes the second heater 60 to stop being energized and turn off.

The first relay 82 and the second relay 84 can be, for example, electromagnetic relays. With this configuration, compared to when the first relay 82 and the second relay 84 are configured using semiconductor switches, there is no need to use a heat dissipation component, and there are fewer restrictions on placement on the board.

The control unit 90 controls the common relay 80, the first relay 82, and the second relay 84 to control the on/off of the first heater 58 and the second heater 60. The control unit 90 differentiates the first timing tmg1 for switching the first heater 58 on from the second timing tmg2 for switching the second heater 60 on. Specifically, the control unit 90 controls the on/off switching timing of the first relay 82 and the second relay 84, staggering the first timing tmg1 and the second timing tmg2. This configuration can prevent inrush currents from increasing in the first heater 58 and the second heater 60. This prevents the inrush currents in the first heater 58 and the second heater 60 from exceeding the breaker capacity. Additionally, if the compressor is configured to limit current in consideration of inrush current, the impact on the compressor can be reduced by preventing the inrush current from increasing.

In addition, the control unit 90 switches the common relay 80 on and off before switching the first relay 82 and the second relay 84 on and off. Specifically, the control unit 90 switches the common relay 80 on before switching the first relay 82 or the second relay 84 on. The control unit 90 switches the common relay 80 off before switching the first relay 82 and the second relay 84 off. This allows the stress (load) on the first relay 82 and the second relay 84 to be distributed by the common relay 80. As a result, the lifespan of the first relay 82 and the second relay 84 can be extended.

The act of turning a relay on and off, which causes current to flow and break, can easily cause stress. For example, the control unit 90 switches the common relay 80 off before switching the first relay 82 and the second relay 84 off. This allows the first relay 82 and the second relay 84 to be switched off when no current is flowing through them. As a result, the stress (load) on the first relay 82 and the second relay 84 can be reduced, and the lifespan of the first relay 82 and the second relay 84 can be extended.

The control unit 90 includes, for example, a memory that stores programs and a processing circuit that corresponds to a processor such as a CPU (Central Processing Unit). The functions of the control unit 90 may be implemented using hardware alone, or may be implemented using a combination of hardware and software. The control unit 90 implements predetermined functions by reading data and programs stored in memory and performing various arithmetic operations.

Figure 7 is a schematic diagram showing control for suppressing inrush current. Figure 7(a) is a schematic diagram of relay control in Example 1, and Figure 7(b) is a graph showing inrush current in Example 1 and Comparative Example 1.

As shown in FIG. 7(a), in Example 1, when turning on the first heater 58 and the second heater 60, the control unit 90 turns on the common relay 80, the first relay 82, and the second relay 84 in that order. Specifically, the control unit 90 turns on the common relay 80 while the common relay 80, the first relay 82, and the second relay 84 are all off. After turning on the common relay 80, the control unit 90 turns on the first relay 82 at a first timing tmg1. The control unit 90 turns on the second relay 84 at a second timing tmg2, a predetermined period of time after the first timing tmg1. In this way, the control unit 90 staggers the timings at which the common relay 80, the first relay 82, and the second relay 84 are switched on.

In Comparative Example 1, the first relay 82 and the second relay 84 are switched on simultaneously. Specifically, in Comparative Example 1, the first relay 82 and the second relay 84 are switched on at the first timing tmg1.

As shown in Figure 7(b), in Comparative Example 1, an inrush current occurs at the first timing tmg1. In Comparative Example 1, inrush currents occur simultaneously in the first heater 58 and the second heater 60 at the first timing tmg1. As a result, two inrush currents occur, and the peak value of the inrush current tends to be large. On the other hand, in Example 1, an inrush current occurs in the first heater 58 at the first timing tmg1, and an inrush current occurs in the second heater 60 at the second timing tmg2. In other words, in Example 1, the inrush current occurs in a dispersed manner.

Comparing the magnitude of the inrush current in Example 1 and Comparative Example 1, the magnitude of the inrush current in Example 1 is smaller than the magnitude of the inrush current in Comparative Example 1. In the example of Figure 7(b), the magnitude of the inrush current at the first timing tmg1 and the second timing tmg2 in Example 1 is approximately half the magnitude of the inrush current at the first timing tmg1 in Comparative Example 1.

In this way, by shifting the first timing tmg1 at which the first relay 82 is switched on and the second timing tmg2 at which the second relay 84 is switched on, the inrush current that occurs when the relay is turned on can be dispersed, and the peak value of the inrush current can be reduced.

Next, we will explain control that utilizes the characteristics of PTC heaters.

Figure 8 is a schematic diagram illustrating the characteristics of a PTC heater. In Figure 8, temperatures T1<T2, Tf1<Tf2, electrical resistances R1>R2, Rf1<Rf2, and fan speeds Vf1>Vf2. Also, "border" indicates the boundary between the negative characteristic region and the positive characteristic region.

As shown in Figure 8, a PTC heater has a negative characteristic region and a positive characteristic region. The "negative characteristic region" is a region where electrical resistance decreases in proportion to temperature. The "positive characteristic region" is a region where electrical resistance increases in proportion to temperature.

When a current flows through a PTC heater in the negative characteristic region, the temperature of the PTC heater rises due to the current flow. As the temperature of the PTC heater rises, the electrical resistance decreases, causing the current to increase. In the negative characteristic region, the PTC heater repeats a cycle of rising temperature, decreasing electrical resistance, and increasing current. As the temperature of the PTC heater rises, it changes from the negative characteristic region to the positive characteristic region.

As shown in Figure 8, in the negative characteristic region, when comparing the electrical resistance R1 at temperature T1 with the electrical resistance R2 at a temperature T2 higher than temperature T1, the electrical resistance R1 is greater than the electrical resistance R2.

Figures 9A and 9B are schematic diagrams illustrating the heater current flowing through a PTC heater in the negative characteristic region. Figure 9A shows the current Ion1 that flows when the PTC heater is turned on at temperature T1 shown in Figure 8, and Figure 9B shows the current Ion2 that flows when the PTC heater is turned on at temperature T2 shown in Figure 8. In Figures 9A and 9B, currents Ion1 and Ion2 represent the currents at the start of current flow.

As shown in Figures 9A and 9B, current Ion1 is smaller than current Ion2. Thus, when the PTC heater is switched on in the negative characteristic region, the lower the temperature, the smaller the current flowing through the PTC heater. In other words, when the PTC heater is switched on in the negative characteristic region, the lower the temperature, the smaller the current at the start of power supply.

In the positive characteristic region, as opposed to the negative characteristic region, as the temperature of the PTC heater rises, the electrical resistance of the PTC heater increases. As the electrical resistance of the PTC heater increases, the current decreases, causing the temperature of the PTC heater to decrease. As the temperature of the PTC heater decreases, the electrical resistance decreases, causing the current to increase. As the current increases, the temperature of the PTC heater rises. In the positive characteristic region, the PTC heater stabilizes by repeating the cycle of temperature increase, electrical resistance increase, current decrease, temperature decrease, electrical resistance decrease, current increase, and temperature increase.

In this embodiment, the first heater 58 and the second heater 60, which are PTC heaters, are configured to be cooled by the wind generated by the first fan 62. Therefore, the temperature of the first heater 58 and the second heater 60 can be adjusted by adjusting the fan speed of the first fan 62. For example, as shown in FIG. 8, when the control unit 90 sets the fan speed of the first fan 62 to Vf1, the temperature of the first heater 58 and the second heater 60 becomes Tf1 and the electrical resistance becomes Rf1. When the control unit 90 sets the fan speed of the first fan 62 to Vf2, which is lower than Vf1, the temperature of the first heater 58 and the second heater 60 rises to Tf2, which is higher than Tf1, and the electrical resistance is adjusted to Rf2, which is higher than Rf1. In this way, the heater temperature and electrical resistance can be adjusted by adjusting the fan speed of the first fan 62.

Figure 10 is a schematic diagram illustrating the heater current flowing through the PTC heater in the positive characteristic region. Figure 10(a) shows the change in fan speed of the first fan 62. Figure 10(b) shows the change in heater temperature of the first heater 58, which is a PTC heater. Figure 10(c) shows the change in electrical resistance of the first heater 58. Figure 10(d) shows the change in heater current of the first heater 58.

As shown in FIG. 10(a), in the positive characteristic region, when the fan speed of the first fan 62 is reduced from Vf1 to Vf2, the temperature of the first heater 58 increases from Tf1 to Tf2, as shown in FIG. 10(b). As a result, the electrical resistance of the first heater 58 increases from Rf1 to Rf2, as shown in FIG. 10(c), and the current of the first heater 58 decreases from Ih1 to Ih2, as shown in FIG. 10(d). In this way, in the positive characteristic region, the higher the temperature of the first heater 58 (PTC heater), the smaller the current. By adjusting the fan speed of the first fan 62, the magnitude of the current flowing through the first heater 58 (PTC heater) can be adjusted.

Next, we will explain the control of turning the first heater 58 and second heater 60 on and off in this embodiment.

Figure 11 is a schematic diagram illustrating relay control, fan speed control, heater current, and heater temperature. Figure 11(a) shows relay control from turning on the first heater 58 and the second heater 60 to turning them off. Figure 11(b) shows fan speed control of the first fan 62. Figure 11(c) shows the change in heater current. Figure 11(d) shows heater temperature.

As shown in FIG. 11 , before the first heater 58 and the second heater 60 are switched on, the first heater 58 and the second heater 60 are cooled for a predetermined cooling period t10. The predetermined cooling period t10 is, for example, 10 seconds or more and 30 seconds or less. Specifically, the control unit 90 increases the fan speed of the first fan 62 to Vfc, thereby increasing the airflow rate of the first fan 62. This cools the first heater 58 and the second heater 60. Note that the fan speed Vfc is greater than the fan speed Vf2 and less than the fan speed Vf1.

The first heater 58 and the second heater 60 are switched on in the negative characteristic region. As described above, in the negative characteristic region, the higher the heater temperature, the lower the electrical resistance and the larger the heater current. Therefore, before the first heater 58 and the second heater 60 are switched on, the initial temperatures of the first heater 58 and the second heater 60 are lowered by blowing air using the first fan 62. This reduces the heater current generated when the first heater 58 and the second heater 60 are switched on, i.e., the current at the start of power supply.

After cooling the first heater 58 and the second heater 60 for a predetermined cooling period t10, the control unit 90 reduces the fan speed Vf of the first fan 62. The control unit 90 reduces the fan speed at the first timing tmg1 and the second timing tmg2 to be lower than the fan speed when both the first heater 58 and the second heater 60 are on. Specifically, the control unit 90 sets the fan speed Vf of the first fan 62 to a fan speed Vf2 that is lower than the fan speed Vf1 when both the first heater 58 and the second heater 60 are on. This promotes a temperature rise after the first heater 58 and the second heater 60 are turned on, enabling a smooth transition from the negative characteristic region to the positive characteristic region.

The control unit 90 also switches on the common relay 80. The common relay 80 is switched on before the first relay 82 and the second relay 84 are switched on.

Next, the control unit 90 switches on the first relay 82 at the first timing tmg1. When the first relay 82 switches on, the first heater 58 is energized and switched on. At the first timing tmg1, an inrush current occurs in the first heater 58, causing the current to temporarily increase but decrease over time. Also, at the first timing tmg1, the first heater 58 is in the negative characteristic region, so when current flows through the first heater 58, the temperature rises. As the temperature rises, the first heater 58 switches from the negative characteristic region to the positive characteristic region.

After switching on the first relay 82, the control unit 90 switches on the second relay 84 at the second timing tmg2. The second timing tmg2 is the timing when the first waiting time t20 has elapsed since the first timing tmg1. The first waiting time t20 is, for example, 15 seconds or more and 45 seconds or less. Preferably, the first waiting time t20 is 30 seconds. When the second relay 84 is switched on, the second heater 60 is energized and switched on. At the second timing tmg2, an inrush current occurs in the second heater 60, so the current temporarily increases, but then decreases over time. Furthermore, at the second timing tmg2, the second heater 60 is in the negative characteristic region, so when current flows through the second heater 60, the temperature increases. As the temperature rises, the second heater 60 switches from the negative characteristic region to the positive characteristic region.

In this way, by shifting the first timing tmg1 at which the first relay 82 is switched on and the second timing tmg2 at which the second relay 84 is switched on, the timing at which inrush current occurs can be spread out compared to when the first heater 58 and the second heater 60 are switched on simultaneously. This reduces the overall peak value of the inrush current. As a result, it is possible to prevent the inrush current from exceeding the breaker capacity. Furthermore, if the compressor is configured to limit current taking inrush current into account, the impact on the compressor can be reduced.

After switching on the second relay 84, the control unit 90 increases the fan speed of the first fan. Specifically, after the second waiting time t21 has elapsed from the second timing tmg2, the control unit 90 sets the fan speed Vf of the first fan 62 to fan speed Vf1, which is higher than fan speed Vf2.

At this time, the first heater 58 and the second heater 60 are in the positive characteristic region. As described above, in the positive characteristic region, the higher the heater temperature, the greater the electrical resistance and the smaller the heater current. Therefore, by adjusting the fan speed of the first fan 62, the heater temperature can be adjusted, and the electrical resistance can be adjusted. This allows the heater current to be adjusted.

The control unit 90 reduces the fan speed Vf of the first fan 62 before switching off the common relay 80, the first relay 82, and the second relay 84. For example, the control unit 90 starts slowing down the fan speed Vf of the first fan 62 a predetermined period t22 before the third timing tmg3 at which the common relay 80 is switched off. The control unit 90 also stops the first fan 62 a predetermined period t11 after the third timing tmg3. The predetermined period t22 is, for example, 10 seconds or more and 30 seconds or less. The predetermined period t11 is, for example, 0.1 seconds or more and 5 seconds or less. Because the third timing tmg3 is in the positive characteristic region, slowing down the fan speed Vf of the first fan 62 increases the temperature of the first heater 58 and the second heater 60, increasing their electrical resistance and reducing the heater current. As a result, stress on the common relay 80 can be reduced.

The control unit 90 switches the common relay 80 off after reducing the fan speed Vf of the first fan 62 and before switching off the first relay 82 and the second relay 84. For example, after switching off the common relay 80 at the third timing tmg3, the control unit 90 switches off the first relay 82 and the second relay 84 after a predetermined period t11 from the third timing tmg3. This switches off the first heater 58 and the second heater 60.

As mentioned above, relays are susceptible to stress when they are turned on and off, causing current to flow and break. For this reason, by switching the common relay 80 off, the first relay 82 and the second relay 84 can be switched off without current flowing through them. This reduces the stress (load) on the first relay 82 and the second relay 84.

This embodiment makes it possible to provide an air conditioner that can reduce the load on the air conditioner's components.

The present invention has been described above using the above-mentioned embodiments, but the present disclosure is not limited to the above-mentioned embodiments.

For example, in the above embodiment, the control unit 90 controls both the first relay 82 and the second relay 84 to be on, but this is not limiting. The control unit 90 may alternately switch on the first relay 82 and the second relay 84.

Figure 12 is a schematic diagram illustrating relay control in variant 1. As shown in Figure 12, while the first relay 82 is on, the second relay 84 is off, and while the second relay 84 is on, the first relay 82 is off. In other words, the first relay 82 and the second relay 84 are not on at the same time. With this configuration, the first heater 58 and the second heater 60 can be turned on alternately to heat efficiently. This shortens the on-time of each heater and reduces the load on the heaters. As a result, the product life of the heaters can be extended.

For example, in the above embodiment, an example was described in which the air conditioner 10 controls the on/off of the first heater 58 and the second heater 60 using the common relay 80, the first relay 82, and the second relay 84, but this is not limited to this. The air conditioner 10 may also control the on/off of the first heater 58 and the second heater 60 using a configuration other than a relay. For example, the on/off of the first heater 58 and the second heater 60 may be controlled using a semiconductor switch such as a MOSFET or an IGBT.

Furthermore, the common relay 80 is not a required component of the air conditioner 10. Even if the air conditioner 10 does not have a common relay 80, by shifting the first timing tmg1 and the second timing tmg2, it is possible to prevent the inrush current from increasing in the first relay 82 and the second relay 84.

For example, in the above embodiment, an example was described in which the control unit 90 reduces the fan speed of the first fan 62 before switching off the first heater 58 and the second heater 60, but this is not limiting. For example, the control unit 90 may reduce the fan speed of the first fan 62 before switching off at least one of the first heater 58 and the second heater 60.

For example, in the above embodiment, an example was described in which the air conditioner 10 is equipped with two heaters 58, 60, but this is not limited to this. The air conditioner may be equipped with two or more heaters.

For example, in the above embodiment, the first heater 58 and the second heater 60 are PTC heaters, but this is not limiting. The first heater 58 and the second heater 60 do not have to be PTC heaters. For example, the first heater 58 and the second heater 60 may be heaters that use nichrome wire, carbon fiber, or the like.

In this embodiment, the control unit 90 reduces the fan speed of the first fan 62 before switching off the first heater 58 and the second heater 60, thereby increasing the temperature of the first heater 58 and the second heater 60, increasing the electrical resistance, and reducing the heater current. However, the control unit 90 does not have to reduce the fan speed of the first fan 62. For example, the air conditioner 10 may increase the temperature of the first heater 58 and the second heater 60, increasing the electrical resistance, and reducing the heater current before switching off the first heater 58 and the second heater 60, without adjusting the fan speed of the first fan 62. The air conditioner 10 may, in any configuration, reduce the heater current before switching off the first heater 58 and the second heater 60. For example, the control unit 90 may reduce the heater current by adjusting the applied voltage. In the positive characteristic region, the current value decreases as the applied voltage increases, and increases as the applied voltage decreases. In the negative characteristic region, the current value increases as the applied voltage increases, and decreases as the applied voltage decreases. Alternatively, an auxiliary heater for adjusting the temperature of the PTC heaters may be placed near heaters 58 and 60. The control unit 90 may control the auxiliary heater to adjust the temperature of heaters 58 and 60, thereby adjusting the resistance value and the current value.

For example, in the above embodiment, the control unit 90 switches on the first relay 82 and then switches on the second relay 84 at the second timing tmg2 after the first waiting time t20 has elapsed. However, this is not limiting. The control unit 90 may distribute the switching on of the first relay 82 and the second relay 84. For example, if the air conditioner 10 has a detection unit that detects heater current, the control unit 90 may determine the timing of switching on the first relay 82 and the second relay 84 based on the heater current detected by the detection. Even with this configuration, the timing of the generation of inrush current in the first heater 58 and the second heater 60 can be shifted. This reduces the stress (load) on the heaters and relays that make up the air conditioner 10.

Note that, in this specification, terms such as "first," "second," etc. are used for descriptive purposes only and should not be understood as expressing or implying the relative importance or ranking of technical features. Features qualified as "first" and "second" expressly or imply the inclusion of one or more of such features.

In other words, the air conditioner according to the embodiment of the present disclosure is, in a broad sense, an air conditioner comprising an indoor unit and an outdoor unit, and comprising: an absorbent material provided in the outdoor unit that absorbs moisture from outdoor air; a flow path through which outdoor air flows that passes through the absorbent material and connects the outdoors with the interior of the indoor unit; a first heater and a second heater that heat the outdoor air upstream of the absorbent material in the flow path; and a control unit that controls the on/off of the first heater and the second heater, wherein the control unit differentiates between a first timing for switching on the first heater and a second timing for switching on the second heater.

This disclosure is applicable to any air conditioner equipped with an indoor unit and an outdoor unit.

10 Air conditioner 20 Indoor unit 30 Outdoor unit 40 Four-way valve 50 Ventilation device 52 Absorbing material 54 Motor 56 Ventilation duct 58 First heater 60 Second heater 62 Fan (first fan)
64 Damper device 66 Fan (second fan)
70 Remote controller 80 Common relay 82 First relay 84 Second relay 90 Control unit P1 Flow path (first flow path)
P2 flow path (second flow path)

Claims (10)

An air conditioner comprising an indoor unit and an outdoor unit,
an absorbent material provided in the outdoor unit that absorbs moisture in the outdoor air;
a flow path through which outdoor air flows, the flow path passing through the absorbent material, connecting the outside of the room with the inside of the indoor unit;
a first heater and a second heater that heat the outdoor air upstream of the absorbent material in the flow path;
a fan that generates a flow of outdoor air in the flow path toward the indoor unit;
a control unit that controls on/off of the first heater and the second heater and controls the fan ;
Equipped with
the first heater and the second heater are each a PTC (Positive Temperature Coefficient) heater;
The control unit
a first timing for switching on the first heater and a second timing for switching on the second heater are made different from each other;
reducing the fan speed of the fan before the first timing and the second timing;
Air conditioner. a first relay for switching on and off the first heater;
a second relay for switching the second heater on and off;
Further provided with
the control unit controls a switching timing for switching on and off the first relay and the second relay, and shifts the first timing from the second timing;
The air conditioner according to claim 1. the second timing is a timing when a first waiting time has elapsed since the first timing;
The air conditioner according to claim 2. the first waiting time is equal to or greater than 15 seconds and equal to or less than 45 seconds;
The air conditioner according to claim 3. a common relay that controls a current flowing through the first relay and the second relay;
the control unit switches the common relay on and off before switching the first relay and the second relay on and off.
The air conditioner according to any one of claims 2 to 4. the control unit controls the fan to cool the first heater and the second heater by blowing air from the fan before turning on the first heater and the second heater.
The air conditioner according to any one of claims 1 to 5 . the control unit increases the fan speed of the fan after a second waiting time has elapsed from the second timing.
The air conditioner according to any one of claims 1 to 6 . the second waiting time is equal to or greater than 15 seconds and equal to or less than 45 seconds;
The air conditioner according to claim 7 . the control unit reduces the fan speed of the fan before switching off at least one of the first heater and the second heater.
The air conditioner according to any one of claims 1 to 8 . the control unit alternately switches on the first relay and the second relay;
The air conditioner according to claim 2.