WO2022269821A1

WO2022269821A1 - Heat-exchange ventilator

Info

Publication number: WO2022269821A1
Application number: PCT/JP2021/023840
Authority: WO
Inventors: 知井ノ口; 福太郎長田
Original assignee: 三菱電機株式会社
Priority date: 2021-06-23
Filing date: 2021-06-23
Publication date: 2022-12-29
Also published as: JPWO2022269821A1

Abstract

A control unit (123) of this heat-exchange ventilator stores the present motor current value of an exhaust motor as a pre-freezing reference current value when the outdoor temperature is less than a predetermined temperature threshold value. When the present motor current value of the exhaust motor after storing the pre-freezing reference current value is equal to or less than a freezing determination current value that is smaller than the pre-freezing reference current value, the control unit (123) determines that ice has formed in the heat exchanger, and performs freezing state improvement control to melt the ice by reducing the air flow rate of an air supply blower (3) below the air flow rate of an exhaust blower (4).

Description

heat exchange ventilation system

The present disclosure relates to a heat exchange ventilation system that performs ventilation while exchanging heat between outdoor air and indoor air using a heat exchanger.

A heat exchange type ventilation system transfers the heat energy of the indoor air that has been conditioned by the indoor air conditioner to the outdoor air through a heat exchanger when the outdoor air is taken into the room. Ventilate while recovering energy.

When the outdoor temperature drops in winter, a heat exchange ventilation system transfers the thermal energy of the discharged indoor air to the outdoor air taken in by the heat exchanger. Moisture held in the air condenses and forms water droplets. Furthermore, when the outdoor temperature drops, the water droplets freeze and become ice, causing clogging of the heat exchanger, resulting in a decrease in heat exchange efficiency or a decrease in exhaust air volume.

For this reason, in a heat exchange type ventilator, the temperature of the outdoor air to be supplied is detected, and if the temperature of the outdoor air falls below a specific temperature, the operation and stop of the supply air blower are stopped for a certain period of time. Clogging of the heat exchanger is prevented by performing repeated intermittent operation or by reducing the output of the supply air blower for a certain period of time.

In Patent Document 1, the motor current value of an exhaust direct current (DC) motor provided in an exhaust fan is monitored, and when the motor current value exceeds a predetermined value, the heat exchanger malfunctions due to freezing. A heat exchange ventilator is disclosed that detects clogging and reduces the rotation speed of an air supply DC motor provided in an air supply fan to melt ice and prevent clogging of a heat exchanger. If the rotation speed of the air supply DC motor is decreased, the ice can be melted, but the ventilation air volume of the heat exchange type ventilation system is limited.

JP 2015-190684 A

However, according to the heat exchange ventilator of Patent Document 1, when the filter is clogged over time and is not caused by freezing of the heat exchanger, the motor current value becomes a predetermined value or more. , the number of revolutions of the air supply DC motor is reduced, and even when there is no need to melt ice to prevent clogging of the heat exchanger, there is a problem that the ventilation air volume is unnecessarily limited. .

The present disclosure has been made in view of the above, and is capable of accurately detecting temporary clogging of a heat exchanger due to freezing, improving the freezing state of the heat exchanger, and temporarily clogging due to freezing. To obtain a heat exchange type ventilator capable of suppressing unnecessary limitation of ventilation air volume caused by improvement operation of a frozen state of a heat exchanger except when the heat exchanger is clogged.

In order to solve the above-described problems and achieve the object, the heat exchange type ventilation device according to the present disclosure includes an exhaust air passage for exhausting indoor air to the outside, a supply air passage for supplying outdoor air to the room, is independently formed inside, an exhaust fan provided in an exhaust air passage and provided with an exhaust motor to generate an exhaust flow flowing through the exhaust air passage, and an air supply motor having an air supply air passage and an air supply blower that is provided in and generates an air supply flow that flows through the air supply air passage. The heat exchange type ventilation device includes a heat exchanger that is provided across the supply air passage and the exhaust air passage and exchanges heat between the supply air flow and the exhaust air flow, and is arranged upstream of the heat exchanger in the exhaust air passage. an exhaust filter, an outdoor temperature detector that detects the outdoor temperature, which is the temperature of the outdoor air, a current detector that detects the motor current value flowing through the exhaust motor, and the operation of the air supply fan and the exhaust fan. and a control unit that controls the The control unit stores a current motor current value of the exhaust motor as a pre-freezing reference current value when the outdoor temperature is less than a predetermined temperature threshold, and stores the current value after storing the pre-freezing reference current value. If the motor current value of the exhaust motor is equal to or less than the freezing determination current value that is smaller than the pre-freezing reference current value, it is determined that the heat exchanger is frozen, and the air volume of the supply air blower is reduced to that of the exhaust air blower. Freeze state improvement control is performed by reducing the air flow to melt the ice.

According to the heat exchange ventilator according to the present disclosure, it is possible to accurately detect temporary clogging of the heat exchanger due to freezing, improve the freezing state of the heat exchanger, and temporarily heat exchange due to freezing. It is possible to suppress unnecessary restrictions on the amount of ventilation air due to the operation to improve the frozen state of the heat exchanger except when the container is clogged.

Schematic diagram showing the configuration of a heat-exchange ventilator according to the first embodiment FIG. 2 is a block diagram showing the functional configuration of the heat exchange ventilator according to the first embodiment; FIG. 4 is a characteristic diagram showing the relationship between the air volume of the fan and the static pressure when constant command voltage control is performed on the fan according to Embodiment 1; FIG. 4 is a characteristic diagram showing the relationship between the motor current and the number of rotations of the blower when constant command voltage control is performed on the blower according to Embodiment 1; A first flow chart showing an operation example of detecting clogging due to freezing of the heat exchanger and improving the freezing state of the heat exchanger in the heat exchange ventilator according to the first embodiment. A second flowchart showing an operation example of an operation for detecting clogging due to freezing of the heat exchanger and an operation for improving the freezing state of the heat exchanger in the heat exchange type ventilator according to the first embodiment. A diagram for explaining an example of freezing state improvement control in the heat exchange ventilator according to the first embodiment. FIG. 1 shows an example of a hardware configuration of a processing circuit according to Embodiment 1; FIG. 3 is a block diagram showing the functional configuration of another heat exchange type ventilation device according to the first embodiment;

Below, the heat exchange type ventilation system according to the embodiment will be described in detail based on the drawings.

Embodiment 1.
FIG. 1 is a schematic diagram showing the configuration of a heat exchange ventilator 1 according to the first embodiment. FIG. 2 is a block diagram showing the functional configuration of the heat exchange ventilator 1 according to the first embodiment. The heat exchange type ventilator 1 is a device capable of performing ventilation while exchanging heat between the supply air flow and the exhaust air flow. The heat exchange type ventilator 1 operates for the purpose of 24-hour ventilation. Therefore, once the heat exchange ventilator 1 starts operating, it basically does not stop operating except during maintenance.

The heat exchange type ventilator 1 maintains a comfortable air environment in the room by ventilating the room by supplying air from the outside to the room and exhausting air from the room to the outside. In addition, the heat exchange type ventilator 1 reduces the temperature difference between the air taken into the room and the air in the room by heat exchange between the supply air flow and the exhaust air flow, thereby reducing the burden of air conditioning in the room. . The heat exchange ventilator 1 is installed, for example, in a space behind the ceiling.

The heat exchange type ventilator 1 includes a housing 1a, a heat exchanger 2, an air supply fan 3, an exhaust fan 4, an air supply filter 5, an exhaust filter 6, and an indoor air outlet 7. , an indoor intake section 8 , an outdoor intake section 9 , an outdoor outlet section 10 , an outdoor temperature detection section 11 , a control device 12 , and a display section 13 .

In the heat exchange type ventilator 1, a heat exchanger 2 that exchanges heat between the supply air flow and the exhaust air flow is housed in the housing 1a. The housing 1 a has, for example, a rectangular parallelepiped hexahedron, and constitutes the main body of the heat exchange ventilator 1 . A supply air passage 21 through which an air supply flow passes, an exhaust air passage 22 through which an exhaust flow passes, and a partition wall 23 that partitions the supply air passage 21 and the exhaust air passage 22 are provided inside the housing 1a. In FIG. 1 , the supply air passage 21 is indicated by a dashed arrow. In FIG. 1, the exhaust air passage 22 is indicated by a solid arrow. FIG. 1 shows the heat exchange ventilator 1 in a state where one surface of the housing 1a is removed from the housing 1a.

On one side surface 1b of the housing 1a, an indoor air outlet 7 as an air supply outlet, an indoor air inlet 8 as an exhaust air inlet, and an outdoor air inlet 9 as an air inlet are provided. , and an outdoor-side blow-out portion 10, which is an exhaust blow-out port, are provided. An outdoor-side air supply duct (not shown) that communicates the outdoor side with the outdoor-side suction part 9 is connected to the outdoor-side suction part 9 that is an air supply suction port. An indoor air supply duct (not shown) that communicates between the room and the indoor air outlet 7 is connected to the indoor air outlet 7 serving as an air supply outlet. An indoor exhaust duct (not shown) that communicates the interior of the room with the indoor intake unit 8 is connected to the indoor intake unit 8 that is an exhaust intake port. An outdoor-side exhaust duct (not shown) that communicates the outdoor side with the outdoor-side blowing portion 10 is connected to the outdoor-side blowing portion 10 that is an exhaust air outlet.

The heat exchanger 2 is provided across the supply airflow path 21 and the exhaust airflow path 22, and performs total heat exchange between the supply airflow and the exhaust airflow. The heat exchanger 2 has a primary side air passage through which the exhaust flow passes and a secondary side air passage through which the supply air flow passes. Inside the heat exchanger 2, the primary air passage and the secondary air passage intersect perpendicularly. The primary side air passage and the secondary side air passage are formed by a laminate configured by alternately laminating and adhering flat sheets of flat paper and corrugated sheets of corrugated paperboard. In FIG. 1, illustration of the primary side air passage and the secondary side air passage is omitted. The laminate has a quadrangular prism shape. The end surfaces of the heat exchanger 2 located at both ends in the stacking direction are square. The stacking direction is the direction in which the flat sheets and the corrugated sheets are stacked, and is the depth direction of the paper surface in FIG.

The supply air passage 21 is an air passage for supplying outdoor air, which is outdoor air, into the room. A supply air path 21a, a downstream side supply air path 21b formed between the heat exchanger 2 and the indoor-side blowout portion 7, which is a supply air outlet, and a heat supply air path 21 in the heat exchanger 2. and an in-exchanger supply air passage 21c. That is, the upstream supply air passage 21a is an air passage on the upstream side of the heat exchanger 2 in the air supply passage 21 and is an upstream air supply passage that communicates with the outside of the room. In addition, the downstream supply air passage 21b is an air passage on the downstream side of the heat exchanger 2 in the air supply passage 21 and communicates with the interior of the room.

The exhaust air passage 22 is an air passage for exhausting return air, which is indoor air, to the outside, and is an upstream exhaust air formed between the indoor side suction part 8 which is an exhaust suction port and the heat exchanger 2. A path 22a, a downstream side exhaust air passage 22b formed between the heat exchanger 2 and the outdoor air outlet 10 that is an exhaust air outlet, and an exhaust air passage 22 in the heat exchanger 2 inside the heat exchanger. and an exhaust air passage 22c. That is, the upstream exhaust air passage 22a is an air passage on the upstream side of the heat exchanger 2 and communicates with the interior of the room. Further, the downstream exhaust air passage 22b is an air passage on the downstream side of the heat exchanger 2 and is a downstream exhaust air passage that communicates with the outside of the room.

A heat exchange type ventilator 1 has a supply air blower 3 that takes in outdoor air and sends the taken in air indoors, and an exhaust fan 4 that takes in indoor air and sends the taken in air outdoors. .

The air supply blower 3 is arranged in the downstream air supply air passage 21 b and generates an air supply flow from the outdoor side suction section 9 toward the indoor side blowout section 7 . The air supply fan 3 includes an air supply fan 31 in an air supply fan casing 30 and a DC brushless motor that is an air supply DC motor 32 for rotating the air supply fan 31 . The air supply fan 3 rotates the air supply fan 31 with the air supply DC motor 32 to generate an air supply flow. The operation of the air supply fan 3 is controlled by the control unit 123 by controlling the operation, stop, and rotation speed of the air supply DC motor 32 by the control unit 123, which will be described later.

The air supply DC motor 32 has an air supply motor control circuit 320 that controls the driving of the air supply DC motor 32 and adjusts the load according to the control of the control unit 123 as a control circuit that is a feature of the DC motor. The air supply motor control circuit 320 controls control parameters such as the voltage output to the air supply DC motor 32, the motor current flowing through the air supply DC motor 32, and the rotation speed of the air supply DC motor 32. The motor power of the air supply DC motor 32 can be adjusted. By acquiring these control parameters, the control unit 123 can grasp the operating state of the air supply DC motor 32 . In the first embodiment, using this feature of the DC motor, the control unit 123 constantly monitors the control parameters of the DC motor 32 for air supply, so that the pressure sensor that detects the pressure of the air passage or the air flowing to the air passage To detect the clogging state of an exhaust filter 6 without using an air volume sensor for detecting the air volume.

The air supply motor control circuit 320 operates the air supply DC motor 32 upon receiving an output instruction from the control unit 123 . Further, when the load applied to the air supply blower 3, such as a change in pressure in the air passage, fluctuates, the load applied to the air supply DC motor 32 also changes, and the rotation speed, voltage, and motor current change. The air supply motor control circuit 320 includes an air supply rotation speed detection unit 321 , an air supply voltage detection unit 322 , an air supply current detection unit 323 , and an air supply communication unit 324 .

The air supply rotation speed detection unit 321 detects the rotation speed of the air supply DC motor 32 . The air supply voltage detector 322 detects the voltage supplied to the air supply DC motor 32 . The air supply current detection unit 323 detects a motor current value, which is the current value of the motor current flowing through the air supply DC motor 32 . The air supply communication unit 324 communicates with the control device 12 . The air supply rotation speed detection unit 321 , the air supply voltage detection unit 322 , and the air supply current detection unit 323 transmit detection results to the control unit 123 via the air supply communication unit 324 .

The exhaust blower 4 is arranged in the downstream exhaust air passage 22b and generates an exhaust flow from the indoor intake section 8 toward the outdoor outlet 10 . The exhaust fan 4 includes an exhaust fan 41 in an exhaust fan casing 40 and a DC brushless motor that is an exhaust DC motor 42 for rotating the exhaust fan 41 . The exhaust fan 4 generates an exhaust flow by rotating the exhaust fan 41 with the exhaust DC motor 42 . The operation of the exhaust fan 4 is controlled by the control unit 123 by controlling the operation, stop, and rotational speed of the exhaust DC motor 42 by the control unit 123, which will be described later.

The exhaust DC motor 42 has an exhaust motor control circuit 420 that controls the driving of the exhaust DC motor 42 and adjusts the load according to the control of the control unit 123 as a control circuit that is a feature of the DC motor. The exhaust motor control circuit 420 controls control parameters such as the voltage output to the exhaust DC motor 42, the motor current value flowing through the exhaust DC motor 42, and the number of rotations of the exhaust DC motor 42. The motor power of motor 42 can be adjusted. By acquiring these control parameters, the control unit 123 can grasp the operating state of the exhaust DC motor 42 .

The exhaust motor control circuit 420 operates the exhaust DC motor 42 upon receiving an output instruction from the control unit 123 . Further, when the load applied to the exhaust blower 4 such as a change in pressure in the air path fluctuates, the load applied to the exhaust DC motor 42 also changes, and the rotation speed, voltage value, and motor current value also change. The exhaust motor control circuit 420 includes an exhaust rotation speed detection unit 421 , an exhaust voltage detection unit 422 , an exhaust current detection unit 423 , and an exhaust communication unit 424 .

The exhaust rotation speed detection unit 421 detects the rotation speed of the exhaust DC motor 42 . The exhaust voltage detector 422 detects the voltage supplied to the exhaust DC motor 42 . The exhaust current detection unit 423 detects a motor current value, which is the current value of the motor current flowing through the exhaust DC motor 42 . The exhaust communication unit 424 communicates with the control device 12 . The exhaust rotation speed detection unit 421 , the exhaust voltage detection unit 422 , and the exhaust current detection unit 423 transmit detection results to the control unit 123 via the exhaust communication unit 424 .

The air supply filter 5 is an air filter that cleans the outside air by removing dust from the outside air sucked into the heat exchanger 2 in order to prevent the performance of the heat exchanger 2 from being clogged with dust contained in the outside air. be. The air supply filter 5 is detachably installed in the upstream air supply air passage 21 a of the air supply air passage 21 . That is, the air supply filter 5 is installed at a position upstream of the heat exchanger 2 in the air supply passage 21 .

The outside air taken into the heat exchange type ventilator 1 passes through the air supply filter 5, and some of the contained suspended particles are removed. The air supply filter 5 can be replaced from a normal dust filter with a high-performance dust filter that can collect fine particulate matter and pollen at a higher collection rate than a normal dust filter.

The exhaust filter 6 is an air filter that removes dust from the return air sucked into the heat exchanger 2 in order to prevent the performance of the heat exchanger 2 from being clogged with dust contained in the return air. The exhaust filter 6 is detachably installed in the upstream side exhaust air passage 22 a of the exhaust air passage 22 . That is, the exhaust filter 6 is installed upstream of the heat exchanger 2 in the exhaust air passage 22 . The return air taken into the heat exchange type ventilator 1 passes through the exhaust filter 6 to remove part of the contained suspended particles.

The outdoor temperature detection unit 11 is a detection unit that detects the outdoor temperature T, which is the temperature of outdoor air sucked into the heat exchange type ventilation device 1 from the outdoors via the outdoor side suction unit 9, that is, the temperature of the outside air. That is, the outdoor temperature detection unit 11 can be rephrased as an outdoor temperature detection unit that detects the temperature of the outdoor air. The outdoor temperature detection unit 11 is provided in an upstream air supply air passage 21 a of the air supply air passage 21 . The outdoor temperature detection unit 11 transmits the detected outdoor air temperature to the control unit 123 .

The display unit 13 displays various warnings such as a clogging warning that the heat exchanger 2 is clogged due to freezing and a freezing warning that freezing may occur in the heat exchanger 2. to be notified. The display unit 13 can notify various warnings by, for example, lighting a light-emitting diode. Details of each warning will be described later.

The control device 12 is provided inside the housing 1a and controls the heat exchange type ventilator 1 as a whole. The control device 12 includes a storage section 121 , a communication section 122 and a control section 123 .

The storage unit 121 stores various information used for controlling the heat exchange ventilator 1 .

The communication unit 122 communicates with devices external to the air supply fan 3, the exhaust fan 4, and the heat exchange type ventilator 1.

The control unit 123 controls the entire heat exchange ventilator 1 including the air supply fan 3 and the exhaust fan 4 . Further, the control unit 123 serves as a determination unit that determines whether temporary clogging of the heat exchanger 2 due to freezing has occurred, and whether clogging of the exhaust filter 6 has occurred over time. have a function.

The control unit 123 controls the ventilation operation of the heat exchange ventilator 1 under predetermined conditions. The predetermined conditions are command voltage constant control to keep the voltage supplied to the DC motor of the blower constant, and ventilation operation with a predetermined ventilation amount. is the same predetermined air volume.

The control unit 123 determines whether or not there is a possibility that freezing will occur in the heat exchanger 2 based on the current outdoor temperature T. That is, the controller 123 compares the current outdoor temperature T with the temperature threshold. When the current outdoor temperature T is equal to or higher than the temperature threshold, the controller 123 determines that the current outdoor temperature and the heat exchanger 2 are in a state where there is no possibility of freezing in the heat exchanger 2 . Further, when the current outdoor temperature T is less than the temperature threshold, the control unit 123 determines that the current outdoor temperature and the heat exchanger 2 are in a state where freezing may occur in the heat exchanger 2. do. That is, based on the current outdoor temperature T, the control unit 123 determines whether or not there is a possibility that freezing will occur in the heat exchanger 2 .

When the current outdoor temperature T is less than the temperature threshold, that is, when the heat exchanger 2 is likely to freeze under the current outdoor temperature T, the control unit 123 controls the current exhaust DC motor The motor current value I of 42 is stored as the pre-icing reference current value _Ii0 . Further, the control unit 123 calculates a current value by subtracting a predetermined set value A from the pre-icing reference current value _Ii0 , and stores the current value as the freezing determination current value _Ii1 . Further, the control unit 123 calculates a current obtained by subtracting a predetermined set value B from the pre-icing reference current value _Ii0 , and stores the calculated current as the freezing improvement determination current value _Ii2 .

The pre-freezing reference current value _Ii0 is determined by the control unit 123 to determine whether or not freezing has occurred in the heat exchanger 2, that is, whether clogging of the heat exchanger 2 has occurred due to freezing. This is a reference motor current value used for determination based on the motor current value. Note that the pre-freezing reference current value _Ii0 may be referred to as the current value _Ii0 .

The icing determination current value _Ii1 determines whether or not icing has occurred in the heat exchanger 2, that is, whether or not clogging of the heat exchanger 2 has occurred due to icing. This is the motor current value used for making decisions based on the current value. The ice-freezing determination current value _Ii1 is a value smaller than the pre-freezing reference current value _Ii0 . Note that the freezing determination current value _Ii1 may be referred to as the current value _Ii1 .

The freezing improvement determination current value _Ii2 indicates the recovery state of the heat exchanger 2 from the freezing state by the freezing state improvement control described later, that is, the improvement state of the freezing state after it is determined that the freezing has occurred in the heat exchanger 2. , are motor current values used for determination by the control unit 123 based on the motor current value of the exhaust DC motor 42 . The freezing improvement determination current value _Ii2 is smaller than the pre-freezing reference current value _Ii0 and greater than the freezing determination current value _Ii1 . Note that the ice improvement determination current value _Ii2 may be referred to as the current value _Ii2 .

The set value A is a subtraction value used to calculate the freezing determination current value _Ii1 based on the pre-freezing reference current value _Ii0 . The set value A is determined in advance through experiments and simulations and stored in the control unit 123 . Further, the control unit 123 can calculate the set value A by multiplying the pre-freezing reference current value _Ii0 by a predetermined ratio. The predetermined ratio is determined in advance through experiments and simulations and stored in control unit 123 .

The set value B is a subtraction value used to calculate the freezing improvement determination current value _Ii2 based on the pre-icing reference current value _Ii0 . The set value B is determined in advance through experiments and simulations and stored in the control unit 123 . Setting value A and setting value B have a magnitude relationship of A>B.

After acquiring the pre-freezing reference current value _Ii0 , the freezing determination current value _Ii1 , and the freezing improvement determination current value _Ii2 , the control unit 123 monitors the current outdoor temperature T, and controls the current exhaust DC motor 42. When the current value I becomes equal to or less than the freezing determination current value _Ii1 , it is determined that freezing has occurred in the heat exchanger 2, that is, clogging of the heat exchanger 2 has occurred due to freezing.

When the current motor current value I of the exhaust DC motor 42 becomes equal to or less than the freezing determination current value _Ii1 , the control unit 123 reduces the air volume of the air supply fan 3 to the exhaust fan 4 for a predetermined operation change time. , to reduce the inflow of outside air, which has a lower temperature than the indoor air, into the heat exchanger 2. As a result, the ice in the heat exchanger 2 can be melted by the heat of the airflow of the indoor air that is conveyed to the heat exchanger 2 by the exhaust air blower 4 and exhausted from the room.

After the freezing state improvement control, the control unit 123 returns the state of the air supply fan 3 to the normal operating state, and based on the amount of change in the motor current value of the exhaust fan 4, the heat exchanger under the freezing state improvement control. 2 to determine the effect of improving the frozen state. When the current motor current value I of the exhaust DC motor 42 is equal to or greater than the freezing improvement determination current value _Ii2 , the control unit 123 has the effect of improving the freezing state of the heat exchanger 2, and there is a possibility that freezing will occur. However, it is determined that the frozen state has been improved. After that, the control unit 123 returns to the operation of determining whether or not there is a possibility that freezing will occur in the heat exchanger 2 based on the current outdoor temperature T.

When the current motor current value I of the exhaust DC motor 42 is less than the freezing improvement determination current value _Ii2 , the control unit 123 determines that the effect of improving the freezing state of the heat exchanger 2 is insufficient. . When the control unit 123 determines that the effect of improving the frozen state of the heat exchanger 2 is insufficient, the current motor current value I of the exhaust DC motor 42 becomes equal to or greater than the current value _Ii2 for the freezing improvement determination. Until the current outdoor temperature T becomes higher than a predetermined temperature threshold, the icing condition improvement control is repeated to alleviate and improve the icing condition of the heat exchanger 2 .

When the freezing state improvement control is repeated, the operation change time C may be extended, and the reduction amount by which the air volume of the air supply fan 3 is reduced below the air volume of the exhaust fan 4 may be increased. As a result, the amount of outside air having a lower temperature than the indoor air flowing into the heat exchanger 2 can be further reduced, and the effect of improving the frozen state of the heat exchanger 2 can be increased.

Here, when the control unit 123 determines that the current motor current value I of the exhaust DC motor 42 is less than the freezing improvement determination current value _Ii2 and that the effect of improving the freezing state of the heat exchanger 2 is insufficient. If the freezing condition improvement control can be repeatedly executed, the user is notified of the freezing condition warning to the effect that the freezing condition can be improved even though the freezing condition has occurred in the heat exchanger 2 .

On the other hand, when the freezing state improvement control is repeated a predetermined number of times, the control unit 123 notifies the user of a freezing clogging warning indicating that temporary clogging of the heat exchanger 2 due to freezing has occurred. .

When the current outdoor temperature T is less than the temperature threshold, that is, when there is a possibility of freezing occurring in the heat exchanger 2 at the current outdoor temperature T, the control unit 123 sets the pre-freezing reference current value I _i0 , the freezing determination current value _Ii1 , and the freezing improvement determination current value _Ii2 are stored until there is no possibility of freezing in the heat exchanger 2. These information are reset when there is no state.

FIG. 3 is a characteristic diagram showing the relationship between the air volume of the fan and the static pressure when the command voltage constant control is performed on the fan according to the first embodiment. FIG. 4 is a characteristic diagram showing the relationship between the motor current and the number of rotations of the blower when constant command voltage control is performed on the blower according to the first embodiment. As shown in FIG. 4, in the blower according to the first embodiment, the motor current required to drive the DC motor decreases as the number of rotations increases during command voltage constant control in which the voltage supplied to the DC motor provided in the blower is constant. have a relationship. The blowers in Embodiment 1 are the air supply blower 3 and the exhaust blower 4 . The DC motors in Embodiment 1 are the air supply DC motor 32 and the exhaust DC motor 42 .

The control unit 123 can acquire the motor current value, which is the current value of the motor current flowing through the air supply DC motor 32 of the air supply blower 3, from the air supply current detection unit 323. 42 can be obtained from the exhaust current detection unit 423. Also, the control unit 123 can acquire the outdoor temperature T, that is, the temperature of the outside air, from the outdoor temperature detection unit 11 . The control unit 123 detects the occurrence of freezing in the heat exchanger 2 and clogging due to freezing in the heat exchanger 2 based on the outdoor temperature and the motor current value of the exhaust DC motor 42 .

In FIG. 3, a characteristic curve 111 represents the relationship between air volume and static pressure. The heat exchange type ventilator 1 has ventilation performance indicated by the characteristic curve 111 . The initial pressure loss curve 112 represents the relationship between the air volume and the static pressure when the heat exchanger 2 is not clogged due to freezing. That is, the initial pressure loss is the pressure loss when the heat exchanger 2 is not frozen. A clogging pressure loss curve 113 represents the relationship between air volume and static pressure when clogging due to freezing occurs in the heat exchanger 2 . That is, the clogging pressure loss is the pressure loss when the heat exchanger 2 is frozen. The air volume at the intersection 114 between the characteristic curve 111 and the initial pressure loss curve 112 is the ventilation air volume by the heat exchange ventilator 1 at the time of the initial pressure loss. The motor current of each fan at this ventilation air volume corresponds to the motor current 131 in FIG.

In the heat exchange type ventilator 1, when the outside air temperature decreases during ventilation operation, condensation occurs in the heat exchanger internal exhaust air passage 22c, which is the exhaust air passage 22 in the heat exchanger 2. That is, when the indoor air flowing through the exhaust air passage 22 exchanges heat with the outdoor air in the heat exchanger 2 and the temperature drops below the dew point, dew condensation occurs. When the temperature of the exhaust gas after heat exchange falls below the freezing temperature, the moisture generated by the dew condensation freezes into ice, clogging the heat exchanger 2, and lowering the ventilation function. That is, when the heat exchanger 2 is clogged due to freezing, the freezing causes airflow resistance, resulting in an increase in pressure loss, which deteriorates the ventilation function.

In order to maintain a predetermined ventilation air volume in command voltage constant control that keeps the voltage supplied to the blower constant when the pressure loss increases due to the freezing of the ice, the control unit 123: Control is performed to decrease the current value of the exhaust DC motor 42 so as to increase the rotation speed of the exhaust DC motor 42 according to the relationship between the rotation speed of the exhaust DC motor 42 and the motor current value of the exhaust DC motor 42 . Frozen ice melts when the outdoor temperature rises or when the amount of heat in the exhausted indoor air increases. That is, clogging of the heat exchanger 2 due to freezing is temporary clogging.

When clogging occurs in the heat exchanger 2 due to freezing, the initial pressure loss curve 112 rises in the direction of the arrow in FIG. A clogging pressure loss curve 113 represents the relationship between the air volume and the static pressure when clogging of the heat exchanger 2 due to freezing occurs, making it difficult for air to pass through the heat exchanger 2 .

In this case, the air volume at the intersection 115 between the characteristic curve 111 and the clogging pressure loss curve 113 is the ventilation air volume from the heat exchange ventilator 1 . The rotation speed of the blower at this ventilation air volume corresponds to the motor current 132 in FIG. At the intersection point 115, the air volume is lower than at the intersection point 114, and even if the blower is rotating, ventilation is difficult. The blower motor current also decreases from the position of motor current 131 to the position of motor current 132 .

Then, the clogging of the heat exchanger 2 due to freezing reduces the ventilation function of the heat exchange type ventilator 1. That is, when the heat exchanger 2 is clogged due to freezing, the clogging of the heat exchanger 2 due to freezing causes airflow resistance, resulting in an increase in pressure loss. lower the

FIG. 5 is a first flowchart showing an operation example of an operation for detecting clogging due to freezing of the heat exchanger 2 and an operation for improving the freezing state of the heat exchanger 2 in the heat exchange type ventilator 1 according to the first embodiment. be. FIG. 6 is a second flowchart showing an operation example of detecting clogging due to freezing of the heat exchanger 2 and improving the freezing state of the heat exchanger 2 in the heat exchange ventilator 1 according to the first embodiment. be.

The control unit 123 acquires the motor current value of the air supply DC motor 32 mounted on the air supply blower 3, and controls the exhaust air from the exhaust DC motor 42 mounted on the exhaust blower 4. The motor current value of the DC motor 42 is acquired, and the outdoor temperature, that is, the airflow temperature of the outdoor air is acquired from the outdoor temperature detection unit 11 . The control unit 123 executes filter clogging and ice clogging detection based on the acquired motor current value of the air supply DC motor 32, the acquired motor current value of the exhaust DC motor 42, and the outdoor temperature. In the heat exchange type ventilator 1, the air supply DC motor 32 mounted on the air supply fan 3 and the exhaust DC motor 42 mounted on the exhaust fan 4 are controlled by command voltage constant control.

The operation of detecting clogging due to freezing of the exhaust filter 6 in the heat exchange type ventilator 1 will be described below.

In step S110, the current outdoor temperature T is monitored after the heat exchange ventilator 1 starts operating. Specifically, the controller 123 acquires the current outdoor temperature T from the outdoor temperature detector 11 . The control unit 123 acquires the current outdoor temperature T at predetermined intervals and monitors the outdoor temperature T. FIG. In addition, the outdoor temperature T may be described as the temperature T. The control unit 123 performs ventilation operation by controlling the operations of the air supply DC motor 32 and the exhaust DC motor 42 in accordance with the detected current outdoor temperature T.

In step S120, it is determined whether or not the current outdoor temperature T is equal to or higher than the first temperature threshold _T0 , which is a temperature threshold. Specifically, the controller 123 compares the current outdoor temperature T acquired in step S110 with the first temperature threshold _T0 to determine whether the heat exchanger 2 is frozen in the current outdoor temperature T state. determines whether there is a possibility that

The first temperature threshold value _T0 is a reference threshold value for the control unit 123 to determine whether or not freezing may occur in the heat exchanger 2, and is determined in advance and stored in the control unit 123. ing. The first temperature threshold value _T0 can be said to be a reference threshold value for determining whether or not the heat exchanger 2 is likely to freeze. Also, the first temperature threshold _T0 can be said to be a freezing warning temperature, which is a temperature at which the possibility of freezing in the heat exchanger 2 should be warned. The first temperature threshold _T0 is, for example, 1°C.

When the current outdoor temperature T is equal to or higher than the first temperature threshold value _T0 , the control unit 123 controls the current outdoor temperature T and the heat exchanger 2 in a state where there is no possibility of freezing in the heat exchanger 2. Determine that there is. In addition, when the current outdoor temperature T is less than the first temperature threshold value _T0 , the control unit 123 determines that the current outdoor temperature T and the heat exchanger 2 may freeze in the heat exchanger 2. state.

If it is determined that the current outdoor temperature T is equal to or higher than the first temperature threshold value _T0 , that is, if it is determined that there is no possibility of freezing occurring in the heat exchanger 2, the result of step S120 is Yes, and step S110 back to If it is determined that the current outdoor temperature T is less than the first temperature threshold _T0 , that is, if it is determined that there is a possibility that freezing will occur in the heat exchanger 2, the result of step S120 is No, and step S130 proceed to

In step S130, it is determined whether or not the pre-icing reference current value _Ii0 , the freezing determination current value _Ii1 , and the freezing improvement determination current value _Ii2 have been acquired. Specifically, the control unit 123 determines whether or not the pre-icing reference current value _Ii0 , the freezing determination current value _Ii1 , and the freezing improvement determination current value _Ii2 are stored in the control unit 123, thereby It is determined whether or not the previous reference current value _Ii0 , the freezing determination current value _Ii1 , and the freezing improvement determination current value _Ii2 have already been acquired.

When the control unit 123 stores the pre-freezing reference current value _Ii0 , the ice-freezing determination current value _Ii1 , and the ice-improvement determination current value _Ii2 , the control unit 123 stores the pre-icing reference current value _Ii0 and the ice-freezing determination current value Ii0. It is determined that the current value _Ii1 and the freezing improvement determination current value _Ii2 have already been acquired. If the control unit 123 does not store the pre-icing reference current value _Ii0 , the freezing determination current value _Ii1 , and the freezing improvement determination current value _Ii2 , the control unit 123 stores the pre-icing reference current value _Ii0 and the freezing determination current value Ii0. It is determined that the current value _Ii1 and the freezing improvement determination current value _Ii2 have not been acquired.

If it is determined that the pre-freezing reference current value _Ii0 , the freezing determination current value _Ii1 , and the freezing improvement determination current value _Ii2 have not been obtained, the determination in step S130 is No, and the process proceeds to step S140. If it is determined that the pre-freezing reference current value _Ii0 , the freezing determination current value _Ii1 , and the freezing improvement determination current value _Ii2 have already been obtained, the determination in step S130 is Yes, and the process proceeds to step S150.

In step S140, the pre-icing reference current value _Ii0 , the freezing determination current value _Ii1 , and the freezing improvement determination current value _Ii2 are obtained. Specifically, the control unit 123 acquires the current motor current value I of the exhaust DC motor 42 from the exhaust current detection unit 423 of the exhaust DC motor 42 mounted on the exhaust fan 4 .

The control unit 123 stores the acquired current motor current value I of the exhaust DC motor 42 as a pre-freezing reference current value _Ii0 . Thereby, the control unit 123 can acquire the pre-freezing reference current value _Ii0 . That is, the control unit 123 can grasp the motor current value I of the exhaust DC motor 42 in the normal state in the pressure loss state of the environment before clogging due to freezing occurs in the heat exchanger 2 .

In this way, the control unit ₁₂₃ _controls the current exhaust DC A motor current value I of the motor 42 is stored as a pre-freezing reference current value _Ii0 .

Further, the control unit 123 calculates a current value by subtracting a predetermined set value A from the pre-icing reference current value _Ii0 . The control unit 123 stores the current value calculated based on the set value A and the pre-freezing reference current value _Ii0 as the freezing determination current value _Ii1 . Thereby, the control unit 123 can acquire the freezing determination current value _Ii1 . Further, the control unit 123 calculates a current by subtracting a predetermined set value B from the pre-icing reference current value _Ii0 . The control unit 123 stores the current value calculated based on the set value B and the pre-freezing reference current value _Ii0 as the ice improvement determination current value _Ii2 . Thereby, the control unit 123 can acquire the freezing improvement determination current value _Ii2 . After that, the process proceeds to step S150.

Since the heat exchange ventilator 1 can change the air volume from a small air volume to a large air volume with the same fan, depending on the ventilation air volume, the pre-freezing reference current value _Ii0 may be relatively high or relatively high. There are cases where it is low, and it does not become a constant value. Therefore, the degree of influence of freezing changes depending on whether the pre-icing reference current value _Ii0 is relatively high or when the pre-icing reference current value _Ii0 is relatively low. When the set value _A is a _{predetermined} constant value, the heat exchanger 2, the control unit 123 may not be able to accurately determine whether or not freezing has occurred.

On the other hand, by multiplying the pre-freezing reference current value _Ii0 by a predetermined ratio to calculate the set value A, when the set value A is set to a constant value as described above, False positives that occur can be avoided. That is, when the pre-freezing reference current value _Ii0 is relatively high, it is suitable for determining whether or not freezing has occurred in the heat exchanger 2 when the pre-icing reference current value _Ii0 is relatively high. Also, the set value A can be set to a relatively large value. Further, when the pre-freezing reference current value _Ii0 is relatively low, it is suitable for determining whether or not freezing has occurred in the heat exchanger 2 when the pre-icing reference current value _Ii0 is relatively low. Also, the set value A can be set to a relatively small value.

In step S150, it is determined whether or not the current outdoor temperature T is equal to or lower than a _second temperature threshold T1, which is a temperature threshold. Specifically, the control unit ₁₂₃ compares the outdoor temperature T obtained in step S110 with the second temperature threshold T1 to determine whether freezing occurs in the heat exchanger 2 at the current outdoor temperature T. Determine whether there is a possibility of

The second temperature threshold T1 is _a threshold that serves as a reference for the control unit 123 to determine whether or not there is a possibility that freezing will occur in the heat exchanger 2, and is determined in advance and stored in the control unit 123. ing. The second temperature threshold value T1 is _a reference threshold value for determining whether or not there is no possibility of freezing in the heat exchanger 2 when steps S160 to S240, which will be described later, are repeated. I can say. That is, the _second temperature threshold T1 can be said to be the freezing safe temperature, which is the temperature at which it can be determined that the heat exchanger 2 will not freeze. The _second temperature threshold T1 is, for example, 3°C. By performing step S<b>150 , it is possible to determine whether there is a possibility that freezing will occur in the heat exchanger 2 .

The control unit 123 determines that the heat exchanger 2 is likely to freeze when the current outdoor temperature T is equal to or lower than the _second temperature threshold T1. Further, the control unit 123 determines that the heat exchanger 2 is in a state where there is no possibility of freezing when the current outdoor temperature T is higher than the _second temperature threshold value T1.

In the flow of step S120→step S130→step S140→step S150 and the flow of step S120→step S130→step S150, it is determined that freezing may occur in the heat exchanger 2 in the flow of No in step S120. has been judged. On the other hand, in the flow of step S230 or step S240→step S150, in order to determine whether or not to continue monitoring the motor current value I of the exhaust DC motor 42 of the exhaust fan 4 in step S190 described later, heat exchange is performed. It is necessary to determine in step S150 whether there is a possibility that freezing will occur in the vessel 2 .

If it is determined that the current outdoor temperature T is equal to or lower than the _second temperature threshold value T1, that is, if it is determined that there is a possibility that freezing will occur in the heat exchanger 2, the result of step S150 is Yes, and step S160 proceed to If it is determined that the current outdoor temperature T is greater than the _second temperature threshold value T1, that is, if it is determined that there is no possibility of freezing occurring in the heat exchanger 2, the result of step S150 is No, and step Proceed to S250.

In step S160, the motor current value I of the exhaust DC motor 42 of the exhaust fan 4 is monitored. Specifically, the control unit 123 acquires the current motor current value I of the exhaust DC motor 42 from the exhaust current detection unit 423 of the exhaust motor control circuit 420 of the exhaust fan 4 . The control unit 123 acquires the motor current value I of the exhaust DC motor 42 at a predetermined cycle and monitors the motor current value I of the exhaust DC motor 42 .

In step S170, it is determined whether or not the current motor current value I of the exhaust DC motor 42 is equal to or less than the freezing determination current value _Ii1 . Specifically, the control unit 123 compares the current motor current value I of the exhaust DC motor 42 acquired in step S160 with the freezing determination current value _Ii1 stored in the control unit 123 to It is determined whether or not the motor current value I of the DC motor 42 is equal to or less than the freezing determination current value _Ii1 . That is, the control unit 123 determines whether or not the current motor current value I of the exhaust DC motor 42 has decreased by the set value A or more from the pre-freezing reference current value _Ii0 .

Here, when the current motor current value I of the exhaust DC motor 42 is equal to or less than the freezing determination current value _Ii1 , the control unit 123 determines that the heat exchanger 2 is frozen. Further, when the current motor current value I of the exhaust DC motor 42 is greater than the freezing determination current value _Ii1 , the control unit 123 determines that the heat exchanger 2 is not frozen.

As shown in FIG. 4, due to an increase in pressure loss due to freezing in the heat exchanger 2, the motor current value I of the exhaust DC motor 42 decreases. Then, when the motor current value I of the exhaust DC motor 42 is equal to or less than the freezing determination current value _Ii1 , the control unit 123 determines that the heat exchanger 2 is frozen.

If it is determined that the current motor current value I of the exhaust DC motor 42 is equal to or less than the freezing determination current value _Ii1 , the determination in step S170 is Yes, and the process proceeds to step S180. If it is determined that the current motor current value I of the exhaust DC motor 42 is greater than the freezing determination current value _Ii1 , the determination in step S170 is No, and the process returns to step S160.

Here, in the heat exchange type ventilator 1, while the current motor current value I of the exhaust DC motor 42 is greater than the freezing determination current value _Ii1 , that is, while No in step S170→step S160 is repeated, A normal operation is performed in which the air volume of the air supply DC motor 32 and the air volume of the exhaust DC motor 42 are the same. That is, the control unit ₁₂₃ controls the current motor current value I is greater than the freezing determination current value _Ii1 , that is, while No in step S170→step S160 is repeated, normal operation is performed with the air volume of the air supply DC motor 32 and the air volume of the exhaust DC motor 42 being the same. to control the operation of the heat exchange type ventilator 1 .

In step S180, the output of the air supply fan 3 is reduced or the air supply fan 3 is stopped during a predetermined operation change time C to melt the ice and improve the ice condition. control is performed. Specifically, the control unit 123 performs control to reduce the output of the air supply fan 3 only during the operation change time C, or control to stop the air supply fan 3 only during the operation change time C. The reduction in the output of the air supply fan 3 is a reduction in the voltage supplied to the air supply fan 3 , that is, the reduction in the voltage supplied to the air supply DC motor 32 . In reducing the output of the air supply fan 3, the output of the air supply fan 3 is reduced by the set value D. Therefore, the control unit 123 performs control to reduce the output of the air supply fan 3 by the set value D only during the operation change time C, or freeze state improvement control to stop the air supply fan 3 only during the operation change time C. I do. The control to reduce the output of the air supply fan 3 only during the operation change time C or the control to stop the air supply fan 3 only during the operation change time C is the air volume of the air supply fan 3 for the operation change time C. is less than the air volume of the exhaust fan 4 .

The operation change time C is the time during which the control unit 123 performs control to change the operation of the air supply fan 3 in order to improve the freezing of the heat exchanger 2 . The operation change time C is determined in advance through experiments and simulations and stored in the control unit 123 . The operation change time C is, for example, 5 minutes. Note that the predetermined operation change time C means the operation change time C set in a series of frozen condition improvement control. The control itself for melting the frozen state to improve the frozen state is the control performed in step S180. On the other hand, in a broad sense, the control for melting the ice to improve the ice condition, including the process of extending or shortening the operation change time C as described later, is a series of ice condition improvement control. can think. That is, the predetermined action change time C includes the initial value of the action change time C, the extended action change time C, and the shortened action change time C, which are predetermined and set before step S180 is performed. including the operation change time C.

The set value D is a reduction amount by which the control unit 123 reduces the output of the air supply fan 3 in order to improve the freezing of the heat exchanger 2 . The set value D is determined in advance through experiments and simulations and stored in the control unit 123 .

By reducing the output of the air supply blower 3, the amount of outside air that is lower in temperature than the indoor air flowing into the heat exchanger 2 is reduced. Ice in the heat exchanger 2 can be melted by the heat possessed by the indoor air flow. Thereby, the heat exchange type ventilator 1 can improve the frozen state of the heat exchanger 2 . In addition, by stopping the supply air blower 3, the outside air having a lower temperature than the indoor air is stopped from flowing into the heat exchanger 2, and is conveyed to the heat exchanger 2 by the exhaust air blower 4 and exhausted from the room. Ice in the heat exchanger 2 can be melted by the heat of the indoor air flow. Thereby, the heat exchange type ventilator 1 can improve the frozen state of the heat exchanger 2 .

After the operation change time C has elapsed, in step S190, the state of the air supply fan 3 is returned to the normal state. Specifically, the control unit 123 restores the state of the air supply fan 3 whose output is reduced in step S180 or the state of the air supply fan 3 which is stopped in step S180 to the normal operation state before step S180.

In step S200, it is determined whether or not the current motor current value I of the exhaust DC motor 42 is equal to or greater than the freezing improvement determination current value _Ii2 . That is, it is determined whether or not the current motor current value I of the exhaust DC motor 42 has increased by more than "AB", which is the difference between the freezing determination current value _Ii1 and the freezing improvement determination current value _Ii2 . be. Specifically, after the control unit 123 returns the air supply fan 3 to the normal operation state in step S190, the current exhaust current detection unit 423 of the exhaust motor control circuit 420 of the exhaust fan 4 detects the current exhaust A motor current value I of the DC motor 42 is acquired. Then, the control unit 123 compares the acquired current motor current value I of the exhaust DC motor 42 with the freezing improvement determination current value _Ii2 stored in the control unit 123, It is determined whether or not the motor current value I is equal to or greater than the ice improvement determination current value _Ii2 .

Here, when the current motor current value I of the exhaust DC motor 42 is equal to or greater than the ice improvement determination current value _Ii2 , the control unit 123 determines that the ice condition of the heat exchanger 2 is improved. . When the current motor current value I of the exhaust DC motor 42 is less than the freezing improvement determination current value _Ii2 , the control unit 123 determines that the effect of improving the freezing state of the heat exchanger 2 is insufficient. . The freezing improvement determination current value _Ii2 corresponds to the motor current 133 positioned between the motor current 131 and the motor current 132 in FIG.

If it is determined that the current motor current value I of the exhaust DC motor 42 is equal to or greater than the freezing improvement determination current value _Ii2 , the determination in step S200 is Yes, and the process proceeds to step S260. In this case, the control unit 123 has the effect of improving the frozen state of the heat exchanger 2, determines that the frozen state has been improved although there is a possibility of freezing, and proceeds to step S260. If it is determined that the current motor current value I of the exhaust DC motor 42 is less than the ice improvement determination current value _Ii2 , the determination in step S200 is No, and the process proceeds to step S210.

In step S210, it is determined whether or not the frozen state in the heat exchanger 2 can be improved depending on whether the current operation change time C is equal to or less than the set value E. Specifically, the control unit 123 determines whether the current operation change time C is equal to or less than the set value E.

The set value E is a reference value for the control unit 123 to determine whether or not the freezing state in the heat exchanger 2 can be improved based on the current operation change time C, and is a value larger than the initial value of the operation change time C. is the time threshold for The set value E is determined in advance through experiments and simulations and stored in the controller 123 .

When the current operation change time C is equal to or less than the set value E, the control unit 123 determines that the freezing state in the heat exchanger 2 can be improved by further performing the freezing state improvement control. When the current operation change time C is greater than the set value E, the control unit 123 determines that clogging due to freezing occurs in the heat exchanger 2, and even if the freezing state improvement control is performed, the freezing in the heat exchanger 2 is prevented. Determine that the condition cannot be improved.

If it is determined that the current operation change time C is equal to or less than the set value E, the answer to step S210 is Yes, and the process proceeds to step S220. If it is determined that the current operation change time C is longer than the set value E, the determination in step S210 is No, and the process proceeds to step S240.

In step S220, the operation change time C is extended. Specifically, the control unit 123 adds a predetermined set value F to the current operation change time C, and stores the result as the operation change time C to be used for the next ice condition improvement control. If the operation change time C used for the current ice condition improvement control is already extended, the control unit 123 adds the set value F to the extended operation change time C. is stored as the operation change time C to be used for the next ice condition improvement control. By extending the operation change time C used for the next frozen condition improvement control, the amount of outside air having a lower temperature than the indoor air flowing into the heat exchanger 2 is further reduced, and the frozen condition of the heat exchanger 2 is improved. effect can be increased. Note that the set value D described above may be increased. By increasing the set value D, it is possible to further reduce the amount of outside air, which is cooler than the indoor air, flowing into the heat exchanger 2, thereby increasing the effect of improving the frozen state of the heat exchanger 2. After that, the process proceeds to step S230.

In the flow of step S220→step S230→step S150, freezing occurs repeatedly unless the temperature conditions are improved in step S150, that is, unless the current outdoor temperature T changes to be greater than the second temperature threshold T1. It is notified that the heat exchanger 2 is in a state where freezing may occur, and the flow of No in step S170→step S160 is repeated to continuously confirm the occurrence of freezing. Further, the flow from Yes in step S170 to step S180 is repeated to continuously perform the ice state improvement control.

The set value F is an extension time that is added to the current operation change time C in order to set the operation change time C to be extended. The set value F is determined in advance through experiments and simulations and stored in the controller 123 .

That is, the operation change time C is extended and set according to the amount of decrease in the current motor current value I of the exhaust DC motor 42 after the operation change time C has elapsed. Then, after the operation change time C is extended and set, the current outdoor temperature T is equal to or lower than the _second temperature threshold T1, and the current motor current value I of the exhaust DC motor 42 is the freezing determination current value _Ii1 . In the following cases, the control for reducing the air volume of the air supply fan 3 by the extended operation change time C below the air volume of the exhaust fan 4 is repeatedly performed.

In step S230, a warning of freezing is issued. Specifically, the control unit 123 controls the display unit 13 to display a freezing occurrence warning. The freezing warning is a warning indicating that the current outdoor temperature T and the heat exchanger 2 are in a state where freezing may occur in the heat exchanger 2 . That is, as long as there is no change in the temperature condition in step S150, i.e., unless there is a change in which the current outdoor temperature T becomes greater than the _second temperature threshold T1, the freezing occurrence warning indicates that freezing may occur in the heat exchanger 2. This is a warning indicating that there is a possibility that the freezing condition improvement control will be repeatedly performed due to the possibility of repeated freezing condition improvement control. The freezing occurrence warning indicates that the freezing level of the freezing generated in the heat exchanger 2 is a light freezing level at which the freezing of the heat exchanger 2 can be melted by the freezing condition improvement control. there is By displaying the freezing occurrence warning on the display unit 13, the user can understand that although the ventilation rate of the heat exchange ventilator 1 has decreased due to the occurrence of freezing in the heat exchanger 2, the freezing state of the heat exchanger 2 has not been improved. recognize that it is possible. After that, the process returns to step S150.

In step S240, a warning of ice clogging is issued. Specifically, the control unit 123 controls the display unit 13 to display the frozen clogging warning. By displaying the ice clogging warning on the display unit 13, the user can recognize that the heat exchanger 2 is temporarily clogged due to ice. After that, the process returns to step S150.

The freezing clogging warning is a warning indicating that temporary clogging of the heat exchanger 2 due to freezing has occurred in the heat exchanger 2 and that the freezing state has not recovered even if the freezing state improvement control is performed. The frozen clogging warning is issued when the level of the frozen state of the ice generated in the heat exchanger 2 cannot be melted by the frozen state improvement control, and the frozen state remains even if the frozen state improvement control is performed. This indicates a severely frozen state level that cannot be recovered.

In step S250, the warning of freezing is canceled. Specifically, the control unit 123 performs control to terminate the display of the freezing occurrence warning on the display unit 13 . Also, the pre-icing reference current value _Ii0 , the freezing determination current value _Ii1 , the freezing improvement determination current value _Ii2 , and the extended operation change time C are cleared. Specifically, the control unit 123 controls the stored pre-icing reference current value _Ii0 , the freezing determination current value _Ii1 , the freezing improvement determination current value _Ii2 , and the extended operation change time C. Delete from section 123 . After that, the process returns to step S110.

In step S260, it is determined whether or not the current motor current value I of the exhaust DC motor 42 has returned to the pre-freezing reference current value _Ii0 . That is, it is determined whether or not the current motor current value I of the exhaust DC motor 42 is greater than or equal to the anti-icing current value _Ii2 and less than the pre-icing reference current value _Ii0 . Specifically, the control unit 123 compares the current motor current value I of the exhaust DC motor 42 acquired in step S200 with the pre-freezing reference current value _Ii0 , thereby determining the current exhaust DC motor 42 has returned to the pre-freezing reference current value _Ii0 . By performing step S260, it is possible to determine whether or not the heat exchanger 2 has recovered from the frozen state.

Here, when the current motor current value I of the exhaust DC motor 42 is equal to the pre-icing reference current value _Ii0 , the control unit 123 determines that the freezing of the heat exchanger 2 has been appropriately improved. It is determined that the heat exchanger 2 has recovered from the frozen state to the normal state. When the current motor current value I of the exhaust DC motor 42 is less than the pre-freezing reference current value _Ii0 , that is, when the motor current value I of the exhaust DC motor 42 does not return to the pre-icing reference current value _Ii0 , the control unit 123 determines that the improvement of the freezing of the heat exchanger 2 is insufficient and that the heat exchanger 2 cannot recover from the freezing state. That is, it is possible to determine whether or not the heat exchanger 2 has recovered from freezing by determining whether the current motor current value I of the exhaust DC motor 42 has returned to the pre-freezing reference current value _Ii0 .

If it is determined that the current motor current value I of the exhaust DC motor 42 has returned to the pre-freezing reference current value _Ii0 , the determination in step S260 is YES, and the process proceeds to step S270. If it is determined that the current motor current value I of the exhaust DC motor 42 has not returned to the pre-freezing reference current value _Ii0 , the determination in step S260 is No, and the process proceeds to step S210.

In step S270, it is determined that the freezing condition improvement control may be excessively performed, and the operation change time C is shortened. Specifically, the control unit 123 subtracts a predetermined set value G from the current operation change time C, and stores the result as the operation change time C to be used for the next frozen state improvement control. If the operation change time C used in the current frozen state improvement control is already extended or shortened, the control unit 123 further sets the set value for the extended or shortened operation change time C. G is subtracted and stored as operation change time C to be used for the next ice condition improvement control. After that, the process proceeds to step S230.

FIG. 7 is a diagram explaining an example of the freezing state improvement control in the heat exchange ventilator 1 according to the first embodiment. In FIG. 7, the state of the DC motor 32 for air supply, the motor current value I of the DC motor 42 for exhaust, and the frozen state of the heat exchanger 2 are shown on the vertical axis. The state of the air supply DC motor 32 is an operating state or a stopped state. The frozen state of the heat exchanger 2 includes a normal state without ice, a frozen state, and a semi-frozen state between the normal state and the frozen state. The horizontal axis in FIG. 7 indicates time.

As shown in FIG. 7, during the operation of the heat exchange ventilator 1, the heat exchanger 2 begins to freeze at time T1. Then, the current motor current value I of the exhaust DC motor 42 decreases from time T1.

At time T2, the frozen state of the heat exchanger 2 is a semi-frozen state between the normal state and the frozen state.

At time T3, the current motor current value I of the exhaust DC motor 42 decreases to the freezing determination current value _Ii1 . At this point, the heat exchanger 2 is frozen. At time T3, the supply air blower 3 is stopped, so that the freezing state improvement control for melting the freezing to improve the freezing state is performed. Time T3 corresponds to Yes in step S170 and step S180 in FIG.

At time T4, the state of the air supply fan 3 is returned to the normal state. At this point, the current motor current value I of the exhaust DC motor 42 has returned to the pre-freezing reference current value _Ii0 . Also, at this point, the heat exchanger 2 has returned to its normal state without ice. Time T4 corresponds to Yes in steps S190 and S200 in FIG.

At time T5, the formation of ice in the heat exchanger 2 begins. Then, the current motor current value I of the exhaust DC motor 42 decreases from time T5.

At time T6, the current motor current value I of the exhaust DC motor 42 decreases to the freezing determination current value _Ii1 . At this point, the heat exchanger 2 is frozen. Then, at time T6, the air supply blower 3 is stopped, so that the frozen state improvement control is performed. Time T6 corresponds to Yes in step S170 and step S180 in FIG.

At time T7, the state of the air supply fan 3 is returned to the normal state. A motor current value I7, which is the current motor current value I of the exhaust DC motor 42 at time T7, is equal to or greater than the ice improvement determination current value _Ii2 , but is less than the pre-icing reference current value _Ii0 . It has not returned to the reference current value _Ii0 . Also, at this point, the heat exchanger 2 has not returned to its normal, non-icing state. Then, since the heat exchanger 2 has not returned to the normal state without freezing, freezing occurs in the heat exchanger 2 in a short period of time, and from time T7, the occurrence of freezing in the heat exchanger 2 begin.

Time T7 corresponds to Yes in steps S190 and S200 in FIG. More specifically, time T7 corresponds to steps S190→Yes in step S200→No in step S260→Yes in step S210→step S220→step S230→step S150 in FIGS. That is, the control unit 123 shifts to control of normal operation. Further, the control unit 123 extends the operation change time C in step S220.

At time T8, the current motor current value I of the exhaust DC motor 42 decreases to the freezing determination current value _Ii1 . At this point, the heat exchanger 2 is frozen. Then, at time T8, the air supply blower 3 is stopped, so that the frozen state improvement control is performed. Here, the icing condition improvement control is performed only during the extended operation change time C. FIG. Time T8 corresponds to Yes in step S170 and step S180 in FIG.

At time T9, the state of the air supply fan 3 is returned to the normal state. At this point, the current motor current value I of the exhaust DC motor 42 has returned to the pre-freezing reference current value _Ii0 . Also, at this point, the heat exchanger 2 has returned to its normal state without ice. Time T9 corresponds to Yes in steps S190 and S200 in FIG.

In determining the motor current value I of the exhaust DC motor 42 in the heat exchange type ventilator 1 as described above, unless both the air supply DC motor 32 and the exhaust DC motor 42 are operating, normal Since the environment differs from that during operation, the motor current value I of the exhaust DC motor 42 cannot be determined correctly. Therefore, in the heat exchange type ventilator 1, the motor current value I of the exhaust DC motor 42 is not determined while the air supply DC motor 32 is stopped. In addition, in the heat exchange ventilator 1, the actual motor current value I of the exhaust DC motor 42 becomes the pre-icing reference current value _Ii0 while the air supply DC motor 32 is stopped in the freezing state improvement control in step S180. Even in such a case, the operation of the stopped air supply DC motor 32 cannot be restarted immediately.

Therefore, after the operation change time C has elapsed, the state of the air supply fan 3 is returned to the normal state in step S190, and then the current motor current value I of the exhaust DC motor 42 is changed when the air supply DC motor 32 is in operation. detect. Then, in the heat exchange type ventilator 1, even if the detected current motor current value I of the exhaust DC motor 42 exceeds the freezing improvement determination current value _Ii2 , as in the state at time T7, In some cases, the ice on the heat exchanger 2 is not completely removed.

Therefore, even if the current motor current value I of the exhaust DC motor 42 detected after the state of the air supply fan 3 is returned to the normal state in step S190 exceeds the freezing improvement judgment current value _Ii2 , the current When the motor current value I of the exhaust DC motor 42 is less than the pre-icing reference current value _Ii0 , the control unit 123 determines that the freezing of the heat exchanger 2 has not been completely removed. judge. Further, the control unit 123 determines that the improvement of the freezing of the heat exchanger 2 is insufficient, and extends the operation change time C used for the freezing state improvement control in the next step S180.

Further, when the current motor current value I of the exhaust DC motor 42 detected after the state of the air supply fan 3 is returned to the normal state in step S190 is equal to the pre-freezing reference current value _Ii0 , The control unit 123 determines that the freezing of the heat exchanger 2 has been appropriately improved and the heat exchanger 2 has recovered from the freezing state to the normal state. Further, the control unit 123 determines that the icing state improvement control may be excessively performed, and shortens the operation change time C used for the icing state improvement control in the next step S180.

That is, unlike FIG. 7, if the operation change time C is too long, the air supply fan 3 is stopped more than necessary. Therefore, when the current motor current value I of the exhaust DC motor 42 detected after the state of the air supply fan 3 is returned to the normal state in step S190 is equal to the pre-freezing reference current value _Ii0 , , the control unit 123 shortens the operation change time C used for the ice condition improvement control in the next step S180.

In the heat exchange type ventilator 1, the control unit 123 repeatedly performs the control described above, so that the freezing state improvement control suitable for improving the freezing of the heat exchanger 2 can be performed.

Each of the control unit 123 of the control device 12, the air supply motor control circuit 320, and the exhaust motor control circuit 420 is implemented as a processing circuit having the hardware configuration shown in FIG. 8, for example. 8 is a diagram illustrating an example of a hardware configuration of a processing circuit according to Embodiment 1. FIG. When the control unit 123 of the control device 12, the air supply motor control circuit 320, and the exhaust motor control circuit 420 are each realized by the processing circuit shown in FIG. Circuit 320 and exhaust motor control circuit 420 are implemented by processor 201 executing a program stored in memory 202 . Also, multiple processors and multiple memories may work together to achieve the above functions. Some of the functions of the control unit 123 of the control device 12, the air supply motor control circuit 320, and the exhaust motor control circuit 420 are implemented as electronic circuits, and the other functions are implemented by the processor 201 and the memory 202. You may make it implement|achieve using.

In the heat exchange type ventilator 1 according to the first embodiment described above, depending on whether the current outdoor temperature T is equal to or higher than the first temperature threshold value _T0 , the heat exchanger 2 in the state of the current outdoor temperature T A primary determination is made as to whether or not freezing may occur. Further, when it is determined in the primary determination that there is a possibility that freezing occurs in the heat exchanger 2, the heat exchange type ventilator 1 determines whether or not freezing has occurred in the heat exchanger 2 by the exhaust DC motor. A secondary determination based on the motor current value I of 42 is performed.

In this way, the heat exchange ventilator 1 detects temporary clogging of the heat exchanger 2 due to freezing in the heat exchange ventilator 1 using two determination parameters. 2 clogging can be determined with high accuracy. As a result, the heat exchange type ventilator 1 can eliminate erroneous detection of clogging of the exhaust filter 6 over time as temporary clogging of the heat exchanger 2 due to freezing. It is possible to suppress unnecessary restrictions on the amount of ventilation air due to the frozen state improvement control being performed when the heat exchanger 2 is not clogged.

Therefore, the heat exchange ventilator 1 accurately determines temporary clogging of the heat exchanger 2 due to freezing that occurs in the heat exchange ventilator 1 without using a pressure sensor or a flow sensor. It is possible to suppress unnecessary restrictions on the ventilation air volume.

In addition, in the heat exchange type ventilator 1, the icing state improvement control for melting the icing to improve the icing state is performed corresponding to the icing state, and the icing state in the heat exchanger 2 is improved. As a result, the heat exchange ventilator 1 can suppress an unnecessary decrease in the air volume when temporary clogging of the heat exchanger 2 due to freezing occurs, and ventilation of the heat exchange ventilator 1 A decrease in the amount can be suppressed. In addition, the heat exchange type ventilator 1 can reduce unnecessary waiting time for melting ice by changing the operation change time C according to the state of freezing, and can suppress unnecessary decrease in ventilation air volume. can.

In addition, the heat exchange ventilator 1 adapts various reference values and set values used when determining the occurrence of temporary clogging of the heat exchanger 2 due to freezing to the installation environment of the heat exchange ventilator 1. can be set to any reasonable value. As a result, the heat exchange ventilator 1 can accurately determine temporary clogging of the heat exchanger 2 due to freezing in accordance with the installation environment of the heat exchange ventilator 1 .

In the first embodiment, the motor current value I of the exhaust DC motor 42 is used to determine the clogging of the heat exchange type ventilator 1, but the motor current of the exhaust DC motor 42 is It is also possible to replace the value I with determination using the rotation speed N of the exhaust DC motor 42 or the command voltage value of the exhaust DC motor 42, which are known techniques.

As described above, according to the heat exchange ventilator 1 according to Embodiment 1, temporary clogging of the heat exchanger 2 due to freezing can be accurately detected, and the freezing state of the heat exchanger 2 can be improved. In addition, it is possible to suppress the unnecessary limitation of the ventilation air volume due to the operation to improve the freezing state of the heat exchanger 2 except when the heat exchanger 2 is temporarily clogged due to freezing. .

In Embodiment 1, an example in which a DC motor is used for the motors used in the air supply fan 3 and the exhaust fan 4 is shown, but the motors used in the air supply fan 3 and the exhaust fan 4 are It is not limited to DC motors. That is, alternating current (AC) motors may be used for the air supply fan 3 and the exhaust fan 4 . Even when AC motors are used for the air supply fan 3 and the exhaust fan 4, the above effects can be obtained by performing the same control as above.

FIG. 9 is a block diagram showing the functional configuration of another heat exchange ventilator 1X according to the first embodiment. In FIG. 9, components similar to those shown in FIG. 2 are assigned the same reference numerals as in FIG. 2, and detailed description thereof is omitted. Another heat exchange ventilator 1X basically has the same configuration and effect as the heat exchange ventilator 1 according to the first embodiment, but AC motors are used for the air supply fan 3 and the exhaust fan 4. is different from the heat exchange ventilator 1 according to the first embodiment.

Another heat exchange type ventilator 1X includes a housing 1a, a heat exchanger 2, an air supply fan 3X, an exhaust fan 4X, an air supply filter 5, an exhaust filter 6, and an indoor air outlet. A unit 7 , an indoor intake unit 8 , an outdoor intake unit 9 , an outdoor outlet unit 10 , an outdoor temperature detection unit 11 , a control device 12X, and a display unit 13 .

The air supply blower 3X is arranged in the downstream air supply air passage 21b and generates an air supply flow from the outdoor side suction section 9 toward the indoor side blowout section 7. The air supply fan 3X includes an air supply fan 31 inside the air supply fan casing 30 and an air supply AC motor 33 for rotating the air supply fan 31 . The air supply fan 3X rotates the air supply fan 31 with the air supply AC motor 33 to generate an air supply flow. The operation of the air supply fan 3X is controlled by the control unit 123X, which will be described later, by controlling the operation, stop, and rotation speed of the air supply AC motor 33 by the control unit 123X.

The exhaust air blower 4X is arranged in the downstream exhaust air passage 22b and generates an exhaust flow from the indoor intake section 8 to the outdoor outlet section 10. The exhaust fan 4X includes an exhaust fan 41 in an exhaust fan casing 40 and an exhaust AC motor 43 for rotating the exhaust fan 41 . The exhaust fan 4X rotates the exhaust fan 41 with the exhaust AC motor 43 to generate an exhaust flow. The operation of the exhaust air blower 4X is controlled by the control unit 123X, which will be described later, by controlling the operation, stop, and rotational speed of the exhaust AC motor 43 by the control unit 123X.

The control device 12X is provided inside the housing 1a and controls the entire heat exchange type ventilator 1X. The control device 12X includes a storage unit 121, a control unit 123X, an air supply current detection unit 124, and an exhaust current detection unit 125.

The control unit 123X controls the entire heat exchange ventilator 1X including the air supply fan 3X and the exhaust fan 4X. Instead of the current value of the motor current flowing through the air supply DC motor 32 and the current value of the motor current flowing through the exhaust DC motor 42, the control unit 123X determines the current value of the motor current flowing through the air supply AC motor 33 and the exhaust current. The same control as that of the control unit 123 of the heat exchange type ventilator 1 according to the first embodiment is performed except that the current value of the motor current flowing through the AC motor 43 is used.

The air-supply current detection unit 124 detects current in the air-supply AC motor 33 using, for example, a measured value of a current measuring device such as a clamp meter clamped on a wire connecting a power supply (not shown) and the air-supply AC motor 33 . It is possible to detect the current value of the flowing motor current. Note that the method for detecting the current value of the motor current flowing through the air supply AC motor 33 is not limited to this.

The exhaust current detection unit 125 uses, for example, a measured value of a current measuring device such as a clamp meter clamped on a wire connecting the power supply (not shown) and the exhaust current detection unit 125, and the current flowing to the exhaust current detection unit 125 is measured. The current value of the motor current can be detected. Note that the method for detecting the current value of the motor current flowing through the exhaust current detection unit 125 is not limited to this.

The other heat exchange type ventilator 1X is configured as described above, and uses the current value of the motor current flowing through the AC motor 33 for air supply and the current value of the motor current flowing through the AC motor 43 for exhausting, Control similar to that shown in FIGS. 5 and 6 can be performed, and effects similar to those of the heat exchange ventilator 1 according to the first embodiment can be obtained. It is also possible to adopt a configuration in which the air supply current detection unit 124 is provided in the air supply fan 3X and the exhaust current detection unit 125 is provided in the exhaust fan 4X. In this case, the air supply fan 3X, the exhaust fan 4X, and the controller 12X can communicate with each other.

The configuration shown in the above embodiment is an example, and can be combined with another known technique, and part of the configuration can be omitted or changed without departing from the scope of the invention. It is possible.

1 heat exchange type ventilator, 1a housing, 1b side, 1X other heat exchange type ventilator, 2 heat exchanger, 3, 3X supply air blower, 4, 4X exhaust air blower, 5 air supply filter, 6 Exhaust Filter 7 Indoor Blow-out Portion 8 Indoor Suction Portion 9 Outdoor Suction Portion 10 Outdoor Blow-out Portion 11 Outdoor Temperature Detector 12, 12X Control Device 13 Display 21 Supply Air Path 21a upstream side air supply air path 21b downstream side air supply air path 21c heat exchanger internal air supply air path 22 exhaust air path 22a upstream side exhaust air path 22b downstream side exhaust air path 22c heat exchanger internal exhaust air path 23 Partition wall 30 Air supply fan casing 31 Air supply fan 32 Air supply DC motor 33 Air supply AC motor 40 Exhaust fan casing 41 Exhaust fan 42 Exhaust DC motor 43 Exhaust 111 characteristic curve 112 initial pressure loss curve 113 clogging pressure loss curve 114, 115 intersection point 121 storage unit 122 communication unit 123, 123X control unit 124 air supply current detection unit 125 exhaust current Detection unit 131 motor current 132 motor current 320 air supply motor control circuit 321 air supply rotation speed detection unit 322 air supply voltage detection unit 323 air supply current detection unit 324 air supply communication unit 420 Exhaust motor control circuit 421 Exhaust rotation speed detection unit 422 Exhaust voltage detection unit 423 Exhaust current detection unit 424 Exhaust communication unit A, B, D, E, F, G Setting values C operation change time, T outdoor temperature, _T0 _first temperature threshold, T1 second temperature threshold.

Claims

A housing in which an exhaust air passage for exhausting indoor air to the outside and a supply air passage for supplying outdoor air to the room are independently formed;
an exhaust fan including an exhaust motor and provided in the exhaust air passage to generate an exhaust flow flowing through the exhaust air passage;
an air supply blower including an air supply motor and provided in the air supply air passage to generate an air supply flow flowing through the air supply air passage;
a heat exchanger provided across the supply airflow path and the exhaust airflow path for exchanging heat between the supply airflow and the exhaust airflow;
an exhaust filter disposed upstream of the heat exchanger in the exhaust air passage;
an outdoor temperature detection unit that detects the outdoor temperature, which is the temperature of the outdoor air;
a current detection unit that detects a motor current value flowing through the exhaust motor;
a control unit that controls the operation of the air supply fan and the exhaust fan;
with
The control unit
storing a current motor current value of the exhaust motor as a pre-freezing reference current value when the outdoor temperature is less than a predetermined temperature threshold;
When the current motor current value of the exhaust motor after the pre-icing reference current value is stored is equal to or less than the ice-freezing determination current value smaller than the pre-icing reference current value, the heat exchanger is frozen. determine that there is
performing ice condition improvement control for melting the ice by reducing the air volume of the air supply blower to be less than the air volume of the exhaust air blower;
A heat exchange type ventilation device characterized by:
The controller controls the icing state improvement until the current motor current value of the exhaust motor becomes smaller than the pre-icing reference current value, larger than the icing determination current value, and equal to or higher than a predetermined ice-freezing improvement determination current value. repeating control,
The heat exchange type ventilator according to claim 1, characterized by:
When the outdoor temperature is less than a predetermined temperature threshold, the control unit controls the air volume of the air supply blower while the current motor current value of the exhaust motor is greater than the freezing determination current value. and performing normal control to make the air volume of the exhaust fan equal to the air volume,
The heat exchange type ventilator according to claim 1 or 2, characterized by:
In the icing state improvement control, the control unit performs control to reduce the air volume of the air supply blower for an operation change time set in the icing state improvement control;
The heat exchange type ventilator according to any one of claims 1 to 3, characterized by:
In the icing state improvement control, the control unit performs control to stop the air supply fan for an operation change time set in the icing state improvement control;
The heat exchange type ventilator according to any one of claims 1 to 3, characterized by:
The control unit calculates the freezing determination current value by adding a predetermined ratio value to the pre-freezing reference current value;
The heat exchange type ventilator according to any one of claims 1 to 5, characterized by: