JP7478921B2 - Ventilation system - Google Patents

Description

The present invention relates to a ventilation system.

In recent years, renovation projects for older apartment buildings have been attracting attention. In particular, there is a demand for ventilation equipment (hereinafter referred to as heat exchange ventilation equipment) that can supply and exhaust air to and from living spaces such as living rooms and that reduces heat loss during ventilation when heating and cooling (see, for example, Patent Document 1).

A heat exchange type ventilation system includes an intake air duct, an exhaust air duct, and a heat exchange element for exchanging heat between the intake air flow passing through the intake air duct and the exhaust air flow passing through the exhaust air duct. The intake air duct and the exhaust air duct communicate the room with the outside and require a ventilation opening to allow air to pass through. In addition, for toilets, bathrooms, etc., an exhaust system for local exhaust is required in addition to the heat exchange type ventilation system. For example, three ventilation openings are required to install a heat exchange type ventilation system and an exhaust system for local exhaust.

However, apartment buildings that require such renovations are often limited to only two vents. In addition, increasing the number of vents is not easy, as it could affect the strength of the building. As a result, there are cases where the number of existing vents is insufficient for the number of heat exchange ventilators and exhaust units that need to be installed.

Therefore, by combining the exhaust flow of an exhaust system that has an intake port that draws in air from multiple locations in the living space and an exhaust port that concentrates the drawn-in air and blows it out at one location with the exhaust flow of a heat exchange ventilation system, it is possible to accommodate the number of existing ventilation ports.

As an example of a specific configuration, consider the case of localized exhaust of the toilet and bathroom by an exhaust system, and air supply and exhaust of the living room by a heat exchanger. In this case, three vents are generally required to prepare the heat exchanger and exhaust systems. However, by combining the exhaust flow from the heat exchanger and exhaust systems and concentrating and exhausting the air from one location, it is possible to get by with just two vents. In other words, the number of vents required can be reduced compared to when the exhaust flow from the heat exchanger and exhaust systems are not combined.

JP 2016-65692 A

However, if the exhaust flow rate that can be concentrated in one place exceeds the combined exhaust flow rate of the heat exchange ventilator and the exhaust system, pressure loss will cause the exhaust air volume to decrease compared to when each device is operated alone. This causes the heat exchange ventilator to have an uneven balance between the supply air volume and the exhaust air volume. This uneven balance between the supply air volume and the exhaust air volume causes problems with the heat exchange ventilator, such as a decrease in heat exchange efficiency and the adhesion of condensation water to the heat exchange element due to excessive latent heat exchange when the outdoor temperature is low compared to the indoor temperature, such as in winter. Furthermore, condensation water can freeze the heat exchange element and block the exhaust air duct, significantly reducing the exhaust capacity, and if it enters the living space, it can cause damage to the room.

The present invention aims to solve the above-mentioned problems of the conventional technology and provide a ventilation system that prevents the balance between the supply air volume and exhaust air volume of the ventilation device from becoming uneven.

In order to achieve this object, a ventilation system according to the present invention comprises a ventilation device, an exhaust device, an airflow junction section that joins a first exhaust flow from the ventilation device and a second exhaust flow from the exhaust device, and a control section that reduces the supply air volume of the supply air flow from the ventilation device in response to a reduction in the exhaust air volume of the first exhaust flow based on a pressure loss caused by the influence of the second exhaust flow at the airflow junction section , the ventilation device comprises: an air supply motor for rotating a centrifugal fan that generates the supply air flow; an exhaust motor for rotating the centrifugal fan that generates the first exhaust flow; a rotation speed detection section that detects the rotation speed of the exhaust motor; and a current detection section that detects a value of a current flowing through the exhaust motor, and the control section controls an output of the exhaust motor so as to keep the exhaust air volume of the first exhaust flow constant against the pressure loss. and an exhaust flow reduction judgment unit which judges a reduction in the exhaust air volume of the first exhaust flow beyond the range of constant air volume control by the constant air volume control unit based on the rotation speed and current value of the exhaust motor, and controls the output of the air supply motor based on the rotation speed of the exhaust motor detected by the rotation speed detection unit and the current value of the exhaust motor detected by the current detection unit. If the exhaust flow reduction judgment unit determines that the exhaust air volume of the first exhaust flow has not decreased, the air supply motor is controlled at a first output, and if the exhaust flow reduction judgment unit determines that the exhaust air volume of the first exhaust flow has decreased, the air supply motor is controlled at a second output smaller than the first output so that the air supply volume of the air supply flow approaches the exhaust air volume of the first exhaust flow , thereby achieving the desired object.

The present invention has the effect of preventing the balance between the supply air volume and exhaust air volume of the ventilation device from becoming uneven.

FIG. 1 is a schematic diagram of a ventilation system according to a first embodiment of the present invention; (a) is a perspective view of the ventilation device; (b) is a side cross-sectional view of the ventilation device; Block diagram showing the configuration of the control unit A flowchart for reducing the supply air volume in response to a reduction in the exhaust air volume by the control unit Schematic diagram of a ventilation system according to a second embodiment. Block diagram showing the configuration of the control unit A flowchart for reducing the supply air volume in response to a reduction in the exhaust air volume by the control unit

The following describes an embodiment of the present invention with reference to the drawings.

(Embodiment 1)
The ventilation system 50 according to the present invention is used, for example, in the case where exhaust air flows from a plurality of fans are concentrated in one location and exhausted to the outdoors.

Using Figure 1, we will explain the outline of the configuration when the ventilation system 50 is installed in the living room, bathroom, and toilet.

The ventilation system 50 according to the present invention includes a ventilation device 1, an exhaust device 2, an airflow junction section 3, and a control section 4.

The ventilation device 1 is a type of fan that is installed on the ceiling surface of a building, and supplies outdoor air to the room and exhausts indoor air to the room. The ventilation device 1 is installed on the ceiling surface of the living room. The ventilation device 1 has a first air intake port 5, a second air intake port 6, a first exhaust port 7, and a second exhaust port 8.

The first air intake 5 is an opening for drawing in air from the outdoors, etc., into the ventilation device 1. The second air intake 6 is an opening for blowing out the air drawn into the ventilation device 1 from the first air intake 5 from the ventilation device 1. The first exhaust 7 is an opening for drawing in air from the living room into the ventilation device 1. The second exhaust 8 is an opening for blowing out the air drawn into the ventilation device 1 from the first exhaust 7 from the ventilation device 1.

The detailed configuration of the ventilation device 1 will be described later.

The exhaust device 2 is a type of fan that is installed on the ceiling of a building and sucks in air from multiple locations and blows it out from one location. The exhaust device 2 is installed on the ceiling of the bathroom. The exhaust device 2 has a first intake port 9, a second intake port 10, and an exhaust port 11.

The first intake port 9 is an opening for drawing air from the bathroom into the exhaust device 2. The second intake port 10 is an opening for drawing air from the toilet into the exhaust device 2. The outlet port 11 is an opening for blowing out the air drawn into the exhaust device 2 from the first intake port 9 and the air drawn into the exhaust device 2 from the second intake port 10 from a single location.

The airflow junction 3 is a type of piping for merging the first exhaust flow from the ventilation device 1 and the second exhaust flow from the exhaust device 2. An example of the airflow junction 3 is a Y-shaped branch pipe. The airflow junction 3 has a first airflow inlet 12, a second airflow inlet 13, and an airflow outlet 14.

The first airflow inlet 12 is an opening for sucking in the first exhaust flow from the ventilation device 1. The second airflow inlet 13 is an opening for sucking in the second exhaust flow from the exhaust device 2. The airflow outlet 14 is an opening for blowing out the merged airflow from the airflow junction section 3 after the first and second exhaust flows are merged by the airflow junction section 3.

The control unit 4 controls the operation of the ventilation device 1. A block diagram showing the connection between the control unit 4 and each component and a flowchart showing the operation control of the ventilation device 1 by the control unit 4 will be described later.

The ventilation system 50 also includes an outdoor air supply duct 15, an indoor air supply duct 16, a first indoor exhaust duct 17, a local exhaust duct 18, a second indoor exhaust duct 19, and an outdoor exhaust duct 20, and is connected to a first ventilation opening 21, a second ventilation opening 22, a living room air outlet 23, a toilet intake duct 24, the living room, a bathroom, a toilet, etc.

The first ventilation opening 21 and the second ventilation opening 22 are holes that connect the indoors and outdoors.

The living room air outlet 23 is an opening for blowing out air transported from the ventilation device 1 by the indoor air supply duct 16.

The toilet inlet 24 is an opening for drawing air from the toilet into the exhaust device 2.

The outdoor air supply duct 15 is a pipe for transporting outdoor air to the ventilation device 1. The outdoor air supply duct 15 connects the first ventilation opening 21 and the first air supply opening 5.

The indoor air supply duct 16 is a pipe for transporting the air blown out from the second air supply port 6 to the living room. The indoor air supply duct 16 connects the second air supply port 6 to the living room air outlet 23.

The indoor first exhaust duct 17 is a pipe for transporting the first exhaust flow blown out from the second exhaust port 8 to the air flow junction 3. The indoor first exhaust duct 17 connects the second exhaust port 8 and the first air flow inlet 12.

The local exhaust duct 18 is a pipe for transporting the air sucked in from the toilet suction port 24 to the exhaust device 2. The local exhaust duct 18 connects the second suction port 10 and the toilet suction port 24.

The indoor second exhaust duct 19 is a pipe for transporting the second exhaust flow blown out from the air outlet 11 to the air flow junction 3. The indoor second exhaust duct 19 connects the air outlet 11 and the second air flow inlet 13.

The outdoor exhaust duct 20 is a pipe for transporting the air blown out from the airflow outlet 14 to the outdoors. The outdoor exhaust duct 20 connects the airflow outlet 14 and the second ventilation opening 22.

The above is an overview of the configuration of the ventilation system 50.

Next, the details of the configuration of the ventilation device 1 will be described with reference to FIG. 2. FIG. 2(a) is a perspective view of the ventilation device 1, and FIG. 2(b) is a side cross-sectional view of the ventilation device 1.

The ventilation device 1 has a box-shaped main body case 25.

The main body case 25 is a metal member made by combining machined sheet metal parts using screws, rivets, etc. The main body case 25 has a first air intake port 5 and a second exhaust port 8 on one side, a second air intake port 6 on the other side, and a first exhaust port 7 on the bottom.

The main body case 25 further includes an intake air fan 26, an intake air motor 27, an exhaust air fan 28, an exhaust air motor 29, a rotation speed detector 30, a current detector 31, a heat exchange element 32, and an intake air temperature detector 33 in the inner space.

The intake fan 26 is an impeller for generating an intake air flow from the first intake port 5 to the second intake port 6. An example of the intake fan 26 is a sirocco fan.

The air supply motor 27 is an electric motor for rotating the air supply fan 26. The air supply motor 27 supports the air supply fan 26 on a rotating shaft (not shown). An example of the type of the air supply motor 27 is a DC motor (Direct Current Motor). An example of a method for driving a DC motor is PWM (Pulse Width Modulation) control.

PWM control is a modulation method that modulates by changing the duty ratio of a pulse wave. The duty ratio refers to the ratio of the period and the pulse width when a periodic pulse wave is emitted. The air supply motor 27 is energized and rotates for the duration of the pulse width. By changing the duty ratio, the output of the air supply motor 27 can be controlled as desired.

The exhaust fan 28 is an impeller for generating an exhaust flow from the first exhaust port 7 to the second exhaust port 8. An example of the exhaust fan 28 is a sirocco fan.

The exhaust motor 29 is a motor for rotating the exhaust fan 28. The exhaust motor 29 supports the exhaust fan 28 on a rotating shaft (not shown). An example of the exhaust motor 29 is a DC motor controlled by PWM, similar to the intake motor 27.

The rotation speed detection unit 30 is a sensor that detects the rotation speed of the exhaust motor 29. An example of the rotation speed detection unit 30 is a Hall sensor that uses the Hall effect.

The current detection unit 31 is a sensor that detects the value of the current flowing to the exhaust motor 29 based on the duty ratio controlled by PWM.

The heat exchange element 32 exchanges heat between the intake air flow from the intake fan 26 and the exhaust air flow from the exhaust fan 28. The heat exchange element 32 is disposed at a position where the intake air path 34 and the exhaust air path 35 intersect, and a part of the heat exchange element 32 forms the intake air path 34 and the exhaust air path 35.

The air intake path 34 is the path of the air intake flow from the first air intake 5 through the air intake fan 26 to the second air intake 6.

The exhaust path 35 is the path of the exhaust flow from the first exhaust port 7 through the exhaust fan 28 to the second exhaust port 8.

The supply air temperature detection unit 33 is a sensor that detects the temperature of the supply air flow. The supply air temperature detection unit 33 is disposed upstream of the heat exchange element 32 in the supply air path 34.

The above is a detailed description of the configuration of the ventilation device 1.

Next, the configuration of the control unit 4 and the connections between the control unit 4 and each component will be described with reference to FIG. 3.

The control unit 4 includes an input unit 4a, a control program 4b, a processing unit 4c, and an output unit 4d.

The input unit 4a is electrically connected to the rotation speed detection unit 30, the current detection unit 31, the supply air temperature detection unit 33, and the operation unit 36 so that they can communicate with each other. The operation unit 36 is part of a remote control or the like for selecting the operation type, such as turning the ventilator 1 on or off, and is installed on the wall of the living room, etc.

The input unit 4a receives inputs of the rotation speed of the exhaust motor 29 detected by the rotation speed detection unit 30, the current value of the exhaust motor 29 detected by the current detection unit 31, the temperature of the intake air flow detected by the intake air temperature detection unit 33, and information on the operation type selected by the operation unit 36.

The control program 4b contains instructions for controlling the operation of the air supply motor 27 and the exhaust motor 29. The control program 4b includes a constant air volume control unit 4e and an exhaust flow reduction determination unit 4f.

The constant air volume control unit 4e is a program that contains instructions for controlling the output of the intake motor 27 and the exhaust motor 29 so as to keep the intake air volume and exhaust air volume constant even when the pressure loss for the intake air flow and exhaust air flow of the ventilation device 1 changes.

The exhaust flow reduction determination unit 4f is a program that contains instructions for determining that the exhaust airflow of the ventilation device 1 has decreased beyond the range of constant airflow control by the constant airflow control unit 4e.

The processing unit 4c executes the commands written in the control program 4b based on the information input from the input unit 4a.

The output unit 4d is electrically connected to the air supply motor 27 and the exhaust motor 29 so as to be able to communicate with each other. The output unit 4d outputs commands obtained by the execution of the control program 4b by the processing unit 4c to the air supply motor 27 and the exhaust motor 29. The operating functions of the air supply motor 27 and the exhaust motor 29 are controlled according to the commands output from the output unit 4d.

The command output from the output unit 4d includes the value of the applied voltage required to operate the air supply motor 27 and the exhaust motor 29.

The above is the configuration of the control unit 4 and the connections between the control unit 4 and each component.

Next, the operation of the ventilation system 50 will be explained using Figure 1.

When the user selects operation ON of the ventilation device 1 via the operation unit 36, the control unit 4 receives an operation ON signal from the input unit 4a. Having received the operation ON signal, the control unit 4 outputs commands obtained by the execution of the control program 4b by the processing unit 4c from the output unit 4d to the air supply motor 27 and the exhaust motor 29.

The air intake motor 27 and the exhaust motor 29 start operating according to the command output from the output unit 4d, and rotate the air intake fan 26 and the exhaust fan 28 that are supported on their axes.

When the intake fan 26 rotates, outdoor air passes through the first ventilation opening 21, the outdoor intake duct 15, and enters the ventilation device 1 through the first intake duct 5. The air that flows into the ventilation device 1 passes through the intake path 34, is blown out from the second intake duct 6, passes through the indoor intake duct 16, and is blown out from the living room outlet 23 into the living room. In this way, the ventilation device 1 transports outdoor air to the living room.

On the other hand, as the exhaust fan 28 rotates, air from the living room enters the ventilation device 1 through the first exhaust port 7. The air that flows into the ventilation device 1 passes through the exhaust path 35, is blown out from the second exhaust port 8, passes through the indoor first exhaust duct 17, and enters the airflow junction section 3 through the first airflow inlet 12. The air that flows into the airflow junction section 3 is blown out from the airflow outlet 14, passes through the outdoor exhaust duct 20, and is blown out to the outdoors through the second ventilation port 22. In this way, the ventilation device 1 transports the air from the living room to the outdoors.

Here, the supply air flow passing through the supply air path 34 exchanges heat with the exhaust air flow passing through the exhaust air path 35 in the heat exchange element 32, and recovers the thermal energy contained in the exhaust air flow. This makes it possible to reduce the loss of thermal energy caused by ventilation when the temperature is controlled by an air conditioner in summer or winter. The heat exchange efficiency is maximized when the balance between the supply air volume and the exhaust air volume is uniform. For this reason, it is preferable to set the voltage applied to the supply air motor 27 and the exhaust air motor 29 so that the supply air volume and the exhaust air volume are equal. However, the length and layout of the piping for transporting air often differ from property to property, and the pressure loss caused by the piping to the supply air flow and the exhaust air flow also varies. For this reason, it is difficult to set the voltage applied to the supply air motor 27 and the exhaust air motor 29 in advance. Therefore, the control unit 4 can perform constant air volume control of the supply air flow and the exhaust air flow by the constant air volume control unit 4e. The constant air volume control by the control unit 4 will be described below.

Constant air volume control is a control method that returns the actual air volume to the target air volume when the pressure loss changes due to external factors such as the length and layout of the piping as described above, causing the actual air volume to deviate from the target air volume. This allows the ventilation device 1 to ventilate at the target air volume regardless of the installation condition of the piping, etc., thereby preventing excessive power consumption due to insufficient ventilation volume or excessive ventilation.

Next, we will explain the basic principles of constant air volume control.

The motor's "rotation speed R for current value I" is uniquely determined for air volume Q and static pressure P. For this reason, the corresponding numerical relationship of "current value I and rotation speed R" that satisfies the target air volume Q when the static pressure P is changed is found, and the data (hereinafter referred to as constant air volume control parameters) is written to the constant air volume control unit 4e. The constant air volume control unit 4e checks whether the rotation speeds of the air supply motor 27 and the exhaust motor 29 detected by the rotation speed detection unit 30 match the rotation speeds of the constant air volume control parameters. If the result of the check shows that the rotation speeds do not match the constant air volume control parameters, the constant air volume control unit 4e outputs a command to control the voltage applied to the motors so that they match the rotation speeds of the constant air volume control parameters. This makes it possible to keep the air volume constant even if the static pressure (pressure loss) changes. In addition, in constant air volume control, there is a problem that the air volume drops suddenly when a static pressure exceeding the limit of constant air volume control is applied. This is not a problem in normal single operation of the ventilator 1, but it is a major problem in this system. This problem will be described later.

The above is how the ventilation system 50 behaves when the ventilation device 1 is operated.

Next, the operation of the ventilation system 50 when the exhaust device 2 is operated will be explained using FIG. 1.

The exhaust device 2 is controlled by an operation ON/OFF switch (not shown) separate from the operation unit 36. When the user turns on the operation of the exhaust device 2, an electric motor (not shown) mounted on the exhaust device 2 is energized, and a fan (not shown) rotates. When the fan of the exhaust device 2 rotates, air from the bathroom is sucked into the exhaust device 2 from the first intake port 9. Air from the toilet passes through the local exhaust duct 18 from the toilet intake port 24 and is sucked into the exhaust device 2 from the second intake port 10. The air sucked into the exhaust device 2 passes through the indoor second exhaust duct 19 from the air outlet 11 and is sucked into the airflow junction 3 from the second airflow inlet 13. The air sucked into the airflow junction 3 passes through the outdoor exhaust duct 20 from the airflow outlet 14 and is exhausted to the outdoors from the second ventilation port 22. As a result, the exhaust device 2 transports the air from the bathroom and the toilet to the outdoors. The above is the operation of the ventilation system 50 when the exhaust device 2 is operated.

Next, the operation of the ventilation system 50 when the ventilation device 1 and the exhaust device 2 are operated will be described with reference to FIG. 1. Note that the air flow from the ventilation device 1 to the airflow junction 3 and the air flow from the exhaust device 2 to the airflow junction 3 have been described above and will not be described here.

The airflow junction 3 joins the air drawn in from the first airflow inlet 12 and the air drawn in from the second airflow inlet 13. The air that has joined together at the airflow junction 3 passes through the airflow outlet 14, the outdoor exhaust duct 20, and is exhausted to the outdoors through the second ventilation opening 22.

The first exhaust flow conveyed from the living room to the outdoors generates a pressure loss due to the influence of the second exhaust flow conveyed from the bathroom and toilet to the outdoors. In this case, the control unit 4 attempts to control the output of the exhaust motor 29 by the constant air volume control unit 4e in order to keep the first exhaust flow at the target air volume. However, the amount of air passing through the outdoor exhaust duct 20 per unit time is determined by the dimensions of the outdoor exhaust duct 20. Therefore, when the total air volume of the first exhaust flow and the second exhaust flow exceeds the air volume that can pass through the outdoor exhaust duct 20, the first exhaust flow and the second exhaust flow are reduced compared to when each device is operated independently. Furthermore, when a pressure loss occurs in the first exhaust flow that exceeds the limit of the constant air volume control by the constant air volume control unit 4e, the reduction in the first exhaust flow is noticeable. The problem in this case will be explained.

Since the ventilation device 1 has an independent air supply path 34 and an exhaust path 35, the volume of the air supply flow by the ventilation device 1 does not decrease even if the first exhaust flow decreases. In other words, the ratio of the air supply volume to the exhaust air volume is large. Therefore, on the one hand, the living room is under positive pressure, so it is expected to have effects such as suppressing the intrusion of pollen into the living room during the intermediate season and suppressing air leakage in winter. However, on the other hand, in winter, if the temperature difference between the outdoor air temperature and the indoor air temperature becomes large, there is a possibility that condensation will occur on the air supply path 34 side of the heat exchange element 32 due to excessive latent heat exchange. Furthermore, if the outdoor air temperature becomes, for example, below 0°C, at which water easily freezes, the condensation water generated on the heat exchange element 32 may freeze.

When the heat exchange element 32 freezes, the opening area of the air supply path 34 decreases or the air supply path 34 becomes blocked, which may reduce the air supply flow by the ventilation device 1 or make it impossible to supply air. To prevent such a phenomenon from occurring, the control unit 4 includes an exhaust flow reduction determination unit 4f, and performs control to reduce the supply air volume when it is determined that the first exhaust flow has decreased. Below, the operation control of the ventilation device 1 when the first exhaust flow by the ventilation device 1 has decreased is explained using the flowchart in Figure 4.

When the operation of the ventilation device 1 is started, the control unit 4 controls the air supply motor 27 with a first output D1 (step S1). The first output D1 is a value selected to achieve the target supply air volume in accordance with the constant air volume control parameter.

Next, the exhaust flow reduction judgment unit 4f judges whether the rotation speed R of the exhaust motor 29 detected by the rotation speed detection unit 30 is a predetermined rotation speed Rmax and the current value I of the exhaust motor 29 detected by the current detection unit 31 is smaller than a predetermined current value Imax (step S2). The predetermined rotation speed Rmax is the maximum rotation speed of the exhaust motor 29 in the range of constant air volume control. The predetermined current value Imax is the maximum current value of the exhaust motor 29 in the range of constant air volume control. If R=Rmax and I=Imax are not true, the exhaust flow reduction judgment unit 4f repeats step S2.

When R=Rmax and I=Imax, the exhaust flow reduction judgment unit 4f judges whether the supply air temperature TA detected by the supply air temperature detection unit 33 is lower than a predetermined temperature T1 (step S3). T1 is a temperature, such as 0°C, at which the condensation water generated on the heat exchange element 32 is likely to start freezing. If TA<T1 is not satisfied, the control unit 4 returns to step S2.

If TA<T1, the exhaust flow reduction judgment unit 4f controls the air supply motor 27 to a second output D2 that is smaller than the first output D1 (step S4). For example, if the first output D1 has a duty ratio of 70%, the second output D2 is set to have a duty ratio of 55%.

The exhaust flow reduction determination unit 4f determines whether the current value I is a predetermined current value Imax while controlling the air supply motor 27 with the second output D2 (step S5).

If the exhaust flow reduction determination unit 4f determines that I=Imax is not true, it determines whether the rotation speed R is less than a predetermined rotation speed Rmax (step S6). If the control unit 4 determines that R<Rmax is not true, it returns to the process of step S4.

When the exhaust flow reduction judgment unit 4f judges that I = Imax or R < Rmax, it judges whether a signal to stop operation of the ventilation device 1 is input (step S7).

If the exhaust flow reduction determination unit 4f determines that a signal to stop operation of the ventilation device 1 has not been input, it returns to the processing of step 1. If the control unit 4 determines that a signal to stop operation has been input, it stops the operation of the ventilation device 1.

The above is the control flowchart when the first exhaust flow of the ventilation device 1 is decreased by the exhaust flow decrease judgment unit 4f.

When the first exhaust flow from the ventilation device 1 decreases due to pressure loss caused by the influence of the second exhaust flow from the exhaust device 2, the constant air volume control unit 4e changes the rotation speed R and current value I of the exhaust motor 29. If it is within the range of constant air volume control, the rotation speed R and current value I increase.

However, if a pressure loss occurs that exceeds the range of constant air volume control, the rotation speed R of the exhaust motor 29 remains at the specified rotation speed Rmax, and the current value I decreases from the specified current value Imax. This is a phenomenon caused by the fact that the exhaust fan 28 is a sirocco fan. When a pressure loss that exceeds the range of constant air volume control is applied to the sirocco type exhaust fan 28, the exhaust fan 28 reduces the amount of work it does to blow air and goes into an idling state, so the load on the exhaust motor 29 decreases and the current value I decreases. Using this characteristic of constant air volume control using a sirocco fan, the exhaust flow reduction determination unit 4f determines a reduction in the first exhaust flow caused by the ventilation device 1.

The exhaust flow reduction judgment unit 4f reduces the supply air flow by the ventilation device 1 in accordance with the reduction in the first exhaust flow by the ventilation device 1, thereby preventing the balance between the supply air volume and exhaust air volume of the ventilation device 1 from becoming uneven, and suppresses a decrease in the heat exchange efficiency by the heat exchange element 32.

The exhaust flow reduction judgment unit 4f also reduces the intake air volume at the timing when the condensation water on the heat exchange element 32 starts to freeze by comparing the intake air temperature TA with a predetermined temperature T1. On the other hand, if there is no risk of the heat exchange element 32 freezing, the intake air volume can be intentionally increased relative to the exhaust air volume, which can be expected to have the effect of maintaining positive pressure in the living room and preventing the intrusion or leakage of pollen contained in the outdoor air.

When the exhaust flow reduction judgment unit 4f reduces the supply air flow by the ventilation device 1 in accordance with the reduction in the first exhaust flow by the ventilation device 1, it is preferable that the exhaust flow reduction judgment unit 4f controls the supply air flow rate to approach the reduced exhaust flow rate. This allows the exhaust flow reduction judgment unit 4f to control the operation of the ventilation device 1 so that the heat exchange efficiency by the heat exchange element 32 is maximized.

The control unit 4 may be mounted on the ventilation device 1 or the operation unit 36. This eliminates the need to install the control unit 4 on a wall of a house or the like and wire it to the ventilation device 1, which is expected to improve the efficiency of the work involved in installing the ventilation system 50.

The exhaust device 2 includes devices with not only an exhaust function but also an air supply function. In other words, the exhaust device 2 is applicable as long as it is a device with an exhaust function. This makes it possible to prevent negative pressure in the bathroom or toilet by simultaneously supplying and exhausting air, which is expected to reduce the possibility of cold air leaking in and causing discomfort to the user.

(Embodiment 2)
A ventilation system 50a according to a second embodiment of the present invention will be described with reference to Fig. 5 to Fig. 7. Fig. 5 shows an outline of the configuration when the ventilation system 50a is installed in a living room, a bathroom, and a toilet. Fig. 6 is a block diagram showing the configuration of the control unit 40. Fig. 7 is an operation control flowchart of the ventilation device 1.

The ventilation system 50a according to the second embodiment of the present invention differs from the ventilation system 50 according to the first embodiment in the following three points.

(1) The ventilation system 50a is equipped with an exhaust temperature detector 60 and an exhaust humidity detector 61 in the living room.

(2) The control unit 40 is equipped with a dew point temperature calculation unit 4h.

(3) The exhaust flow reduction judgment unit 4f reduces the supply air flow rate of the ventilation device 1 based on the magnitude relationship between the supply air temperature TA and the dew point temperature Td.

Other than the above three points, the configuration of the ventilation system 50a is the same as that of the ventilation system 50 according to embodiment 1. Below, the contents already explained in embodiment 1 will not be explained again as appropriate, and differences from embodiment 1 will be mainly explained.

As shown in FIG. 5, the ventilation system 50a includes an exhaust temperature detection unit 60 and an exhaust humidity detection unit 61.

The exhaust temperature detector 60 measures the temperature of the air in the living room. The exhaust temperature detector 60 is installed on a wall or the like in the living room. The exhaust temperature detector 60 is electrically connected to the input unit 4a so that it can communicate with the input unit 4a.

The exhaust humidity detector 61 measures the humidity of the air in the living room. The exhaust humidity detector 61 is installed on a wall surface of the living room, etc. The exhaust humidity detector 61 is electrically connected to the input unit 4a so that it can communicate with the living room.

As shown in FIG. 6, in the control unit 40, the control program 40b includes a dew point temperature calculation unit 4h.

The dew point temperature calculation unit 4h uses the processing unit 4c to calculate the dew point temperature Td based on the exhaust temperature TB detected by the exhaust temperature detection unit 60 and the exhaust humidity HB detected by the exhaust humidity detection unit 61. The dew point temperature Td is the temperature at which moisture condenses when the air in the living room that contains moisture is cooled.

As shown in FIG. 7, the exhaust flow reduction determination unit 4f determines whether the supply air temperature TA detected by the supply air temperature detection unit 33 is lower than the dew point temperature Td calculated by the dew point temperature calculation unit 4h (step S8). If the exhaust flow reduction determination unit 4f determines that TA<Td, it proceeds to the process of step S4 and controls the supply air motor 27 with a second output D2 that is lower than the first output D1.

In winter, condensation occurs on the heat exchange element 32 because the temperature of the first exhaust air flow falls below the dew point temperature Td as a result of heat exchange between the supply air flow of the ventilation device 1 and the first exhaust air flow of the ventilation device 1. The warm air exhausted from the living room is cooled by heat exchange with the cold air supplied from outside, the amount of saturated water vapor decreases, and condensation occurs. However, if the supply air temperature TA is higher than the dew point temperature Td, the first exhaust air flow exchanges heat with the supply air flow, which has a temperature higher than the dew point temperature, so condensation does not occur on the heat exchange element 32. If condensation does not occur, the possibility of the heat exchange element 32 freezing can also be suppressed.

In this way, the exhaust flow reduction judgment unit 4f can accurately judge the occurrence of condensation by referring to the supply air temperature TA and the dew point temperature Td. As a result, the ventilation system 50a is expected to have the effect of suppressing the occurrence of condensation on the heat exchange element 32.

The exhaust temperature detection unit 60 and the exhaust humidity detection unit 61 are preferably disposed near the first exhaust port 7. By disposing the exhaust temperature detection unit 60 and the exhaust humidity detection unit 61 near the first exhaust port 7, the temperature and humidity of the first exhaust flow sucked into the ventilation device 1 from the first exhaust port 7 can be detected with high accuracy. This is expected to have the effect of allowing the exhaust flow reduction determination unit 4f to perform a determination of the occurrence of condensation based on a more accurate dew point temperature Td.

The ventilation system 50 according to the present invention has been described above based on an embodiment, but the present invention is not limited to the embodiment. As long as it does not deviate from the spirit of the present invention, various modifications that a person skilled in the art may make to this embodiment are also included within the scope of the present invention.

The present invention can be used as a ventilation system that provides ventilation to multiple spaces such as living rooms and bathrooms.

REFERENCE SIGNS LIST 1 Ventilation device 2 Exhaust device 3 Air flow confluence section 4 Control section 4a Input section 4b Control program 4c Processing section 4d Output section 4e Constant air volume control section 4f Exhaust flow reduction determination section 4h Dew point temperature calculation section 5 First air supply port 6 Second air supply port 7 First exhaust port 8 Second exhaust port 9 First intake port 10 Second intake port 11 Air outlet 12 First air flow inlet 13 Second air flow inlet 14 Air flow outlet 15 Outdoor air supply duct 16 Indoor air supply duct 17 Indoor first exhaust duct 18 Local exhaust duct 19 Indoor second exhaust duct 20 Outdoor exhaust duct 21 First ventilation port 22 Second ventilation port 23 Living room exhaust port 24 Toilet intake port 25 Main body case 26 Air supply fan 27 Air supply motor 28 Exhaust fan 29 Exhaust motor 30 Revolution speed detection section 31 Current detection section 32 Heat exchange element 33 Supply air temperature detection section 34 Supply air path 35 Exhaust air path 36 Operation section 40 Control section 40b Control program 50 Ventilation system 50a Ventilation system 60 Exhaust air temperature detection section 61 Exhaust air humidity detection section D1 First output D2 Second output R Revolution speed Rmax Predetermined revolution speed I Current value Imax Predetermined current value TA Supply air temperature TB Exhaust air temperature HB Exhaust air humidity T1 Predetermined temperature Td Dew point temperature

Claims (7)

A ventilation system;
An exhaust system;
an airflow junction that joins a first exhaust air flow from the ventilation device and a second exhaust air flow from the exhaust device;
a control unit that reduces a supply air volume of the supply air flow from the ventilation device in response to a reduced exhaust air volume of the first exhaust air flow based on a pressure loss caused by an influence of the second exhaust air flow at the air flow junction,
The ventilation device includes:
an intake air motor for rotating a centrifugal fan that generates an intake air flow;
an exhaust motor for rotating a centrifugal fan that generates the first exhaust flow;
A rotation speed detection unit that detects the rotation speed of the exhaust motor;
A current detection unit that detects a current value flowing through the exhaust motor,
The control unit is
an air volume constant control unit that controls an output of the exhaust motor so as to keep an exhaust air volume of the first exhaust flow constant with respect to the pressure loss;
and an exhaust flow reduction determination unit that determines a reduction in the exhaust air volume of the first exhaust flow beyond a range of constant air volume control by the constant air volume control unit based on a rotation speed and a current value of the exhaust motor,
controlling an output of the air supply motor based on the rotation speed of the exhaust motor detected by the rotation speed detection unit and the current value of the exhaust motor detected by the current detection unit;
When the exhaust flow reduction determination unit determines that the exhaust air volume of the first exhaust flow is not reduced, the exhaust air supply motor is controlled to a first output;
When the exhaust flow reduction judgment unit judges that the exhaust air volume of the first exhaust flow has decreased, the ventilation system controls the air supply motor at a second output smaller than the first output so that the air supply volume of the air supply flow approaches the exhaust air volume of the first exhaust flow. The exhaust flow reduction determination unit
The ventilation system according to claim 1, wherein when the exhaust motor has a rotational speed at a predetermined rotational speed and a current value of the exhaust motor becomes smaller than a predetermined current value, it is determined that the exhaust air volume of the first exhaust flow has decreased. The exhaust flow reduction determination unit
The ventilation system according to claim 2 , wherein when the current value of the exhaust motor returns to the predetermined current value, it is determined that the exhaust air volume of the first exhaust flow has not decreased. The exhaust flow reduction determination unit
The ventilation system according to claim 3 , wherein when the rotation speed of the exhaust motor becomes lower than the predetermined rotation speed, it is determined that the exhaust air volume of the first exhaust flow is not decreasing. The ventilation device includes:
2. The ventilation system of claim 1, further comprising a heat exchange element for exchanging heat between the supply air flow and the first exhaust air flow. The ventilation device includes:
an intake air temperature detection unit that detects the temperature of the intake air flow,
The control unit is
6. The ventilation system according to claim 5, wherein an output of the air supply motor is controlled when the temperature detected by the air supply temperature detection unit is lower than a predetermined temperature. an exhaust temperature detector that detects an exhaust temperature of the first exhaust flow;
an exhaust humidity detection unit that detects the exhaust humidity of the first exhaust air flow,
The control unit is
a dew point temperature calculation unit that calculates a dew point temperature of the first exhaust air flow based on the exhaust air temperature and the exhaust air humidity,
The ventilation system according to claim 5 , wherein an output of the supply air motor is suppressed when the supply air temperature is lower than the dew point temperature.

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