Ventilation system, air conditioning device, and control method

Abstract

The present application provides a ventilation system, an air conditioning device and a control method, which can measure the air quality actually supplied to the indoor, and can properly control the supply and exhaust of air. The ventilation system includes: a supply air duct (18) provided with a supply fan (21) for supplying outdoor air to the indoor; an exhaust air duct (19) provided with an exhaust fan (23) for exhausting indoor air to the outdoor; a heat exchanger (11) arranged in the middle of the supply air duct (18) and the exhaust air duct (19), which at least exchanges heat between the indoor air and the outdoor air; an IAQ sensor (31) arranged near the indoor to measure the air quality of the outdoor air after passing through the heat exchanger (11) and supplied to the indoor by the supply fan (21); and a control circuit (30) for controlling the supply and exhaust of the supply fan (21) and the exhaust fan (23) based on the measurement result of the IAQ sensor (31).

Description

TECHNICAL FIELD

[0001] The present application relates to a ventilation system that controls supply and exhaust air, an air conditioning device, and a control method. BACKGROUND

[0002] Buildings such as houses, office buildings, and hospitals have improved air tightness for energy saving and comfort. When the air tightness of a building is improved, water vapor, carbon dioxide, and various odor components generated indoors are accumulated as pollutants, and the indoor air quality (IAQ) easily deteriorates. Therefore, in order to exhaust these pollutants to the outside, introduce fresh air from the outside, and maintain the air quality, the necessity of a ventilation system is increasing.

[0003] Ventilation systems include a system that performs only supply and exhaust of indoor and outdoor air, a system that has a sensible heat exchange element that enables movement of heat in supply and exhaust, and a system that has a total heat exchange element that enables movement of heat and humidity in supply and exhaust.

[0004] As the system having the total heat exchange element, a system that controls the air volume and the ventilation mode in accordance with the air quality of the introduced outdoor air (OA) and the air quality of the air (RA) in the exhaust air is known (for example, refer to Patent Literature 1). In this system, a CO2 sensor is provided in the exhaust air passage, the CO2 concentration of the air in the exhaust air is detected, and the air volume control of the supply and exhaust is performed on the basis of the detected CO2 concentration.

[0005] Patent Literature 1: Japanese Patent No. 3480402 SUMMARY

[0006] However, in the above-described related art, since the CO2 sensor is provided in the exhaust air passage, the air quality of the outdoor air cannot be measured. Therefore, even in the case where the CO2 concentration, PM2.5, or the like of the outdoor air increases, the air volume cannot be reduced or the fan cannot be stopped.

[0007] By providing the sensor in the outdoor air introduction portion, the air quality of the outdoor air can be measured, but in the system having the total heat exchanger, the measured air quality does not indicate the air quality of the air supplied to the indoor, and thus there is a problem that the precision of the supply and exhaust control is low.

[0008] The present application provides a ventilation system that controls supply and exhaust air, the ventilation system including:

[0009] a supply air duct that has a supply unit that supplies outdoor air to the indoor;

[0010] an exhaust air duct that has an exhaust unit that exhausts indoor air to the outdoor;

[0011] a heat exchanger configured in the middle of the supply air duct and the exhaust air duct to perform heat exchange between the air in the room and the air outside the room;

[0012] a measurement unit provided near the room to measure the air quality of the air outside the room after passing through the heat exchanger, which is supplied to the room by the supply unit; and

[0013] a control unit to control the supply and exhaust of air by the supply unit and the exhaust unit based on the measurement result of the measurement unit.

[0014] According to the present application, the air quality actually supplied to the room can be measured, and the precision of the supply and exhaust control can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a diagram showing a configuration example of a ventilation system.

[0016] Figure 2 is a diagram showing an example of a hardware configuration of a control circuit.

[0017] Figure 3 is a diagram for explaining a trapping efficiency.

[0018] Figure 4 is a diagram for explaining a total heat exchange and a normal ventilation.

[0019] Figure 5 is a diagram for explaining a configuration example of a ventilation system provided with a total heat exchanger of a rotating rotor type and a baffle control.

[0020] Figure 6 is a flowchart showing an example of supply and exhaust control.

[0021] Figure 7 is a diagram showing a first construction example when a ventilation system is installed.

[0022] Figure 8 is a diagram showing a second construction example when a ventilation system is installed.

[0023] Figure 9 is a diagram for explaining a method of predicting degradation of a filter.

[0024] Figure 10 is a diagram for explaining a method of predicting degradation of an element of a total heat exchanger.

[0025] SYMBOL EXPLANATION

[0026] 10... case

[0027] 11... heat exchanger

[0028] 11a full heat exchange element

[0029] 11b element filter

[0030] 12... air supply inlet

[0031] 13... air exhaust outlet

[0032] 14... air supply outlet

[0033] 15... air inlet

[0034] 16, 17... partition

[0035] 18... air supply duct

[0036] 19... air exhaust duct

[0037] 20... bypass duct

[0038] 21... air supply fan

[0039] 22... baffle

[0040] 23... air exhaust fan

[0041] 24... air supply passage

[0042] 25... air exhaust passage

[0043] 26... natural evaporation type humidifier

[0044] 27... electric heater

[0045] 28... straight expansion type heat exchanger

[0046] 29... filter

[0047] 30... control circuit

[0048] 31... IAQ sensor

[0049] 32... rotor

[0050] 40... CPU

[0051] 41... flash memory

[0052] 42... RAM

[0053] 43... communication I / F

[0054] 44... control I / F

[0055] 45... bus

[0056] 50, 51... pipe

[0057] 52... indoor unit

[0058] 53... tube DETAILED DESCRIPTION

[0059] Figure 1 is a diagram showing a structure example of a ventilation system of the present embodiment. The ventilation system is a system that exchanges indoor air with outdoor air in order to secure the air quality of indoor air of a building. The air quality indicates the component amount of an object substance in the indoor air, and the object substance is carbon dioxide, carbon monoxide, dust such as PM2.5 or PM10, volatile organic compounds, or the like.

[0060] As shown in (a) of FIG. 1, Figure 1 The ventilation system has a substantially rectangular parallelepiped case 10 and a heat exchanger 11 arranged in the case 10. A supply air introduction port 12 that introduces outdoor air (OA) and an exhaust air discharge port 13 that discharges indoor air as EA (Exhaust Air) to the outside are provided at one end in the length direction of the case 10. A supply air blowout port 14 that supplies air introduced from the supply air introduction port 12 as SA (Supply Air) to the inside and an exhaust air introduction port 15 that introduces indoor air as RA are provided at the other end in the length direction of the case 10. A partition 16, 17 is provided in the case 10, a supply air duct 18 that communicates the supply air introduction port 12 with the supply air blowout port 14 via the heat exchanger 11 arranged at a substantially central position in the case 10 is formed, and an exhaust air duct 19 that communicates the exhaust air discharge port 13 with the exhaust air introduction port 15 via the heat exchanger 11 is formed. The supply air duct 18 and the exhaust air duct 19 are formed so as to cross in the heat exchanger 11.

[0061] In the case 10, in addition to the supply air duct 18 and the exhaust air duct 19, a bypass duct 20 that communicates the exhaust air discharge port 13 with the exhaust air introduction port 15 bypassing the heat exchanger 11 is formed. Figure 1 The bypass duct 20 in FIG. 1 communicates with the suction side of an exhaust air fan 23 provided on the outdoor side of the heat exchanger 11 and in the exhaust air duct 19. The exhaust air fan 23 is sometimes provided between the heat exchanger 11 and the exhaust air introduction port 15, but the bypass duct 20 takes a path bypassing the heat exchanger 11. The bypass duct 20 is provided on the exhaust air introduction port 15 side in Figure 1 In FIG. 1, a damper 22 as an opening and closing unit is provided on the exhaust air introduction port 15 side, and by closing the damper 22, it is possible to make the indoor air flow via the heat exchanger 11, and by opening the damper 22, it is possible to make the indoor air flow bypassing the heat exchanger 11. Further, the damper 22 and the bypass duct 20 can be provided at a position that communicates the supply air blowout port 14 with the supply air introduction port 12.

[0062] As a supply air unit that introduces outdoor air (OA) to the inside, in Figure 1An air supply fan 21 is provided between the heat exchanger 11 and the air supply outlet 14 in the air supply duct 18. Alternatively, the air supply fan 21 may be provided between the heat exchanger 11 and the air supply inlet 12.

[0063] An exhaust fan 23 is installed in the exhaust duct 19 as an exhaust unit that exhausts indoor air (RA) to the outside. Figure 1 The exhaust fan 23 shown is located between the heat exchanger 11 and the exhaust outlet 13 in the exhaust duct 19, but it is not limited to this and can also be located between the heat exchanger 11 and the exhaust inlet 15.

[0064] The heat exchanger 11 can be a sensible heat exchanger that only exchanges heat between the air flowing in the supply air duct 18 and the air flowing in the exhaust air duct 19, or it can be a total heat exchanger that exchanges not only heat but also moisture (humidity). Hereinafter, the heat exchanger 11 will be described as a total heat exchanger.

[0065] The total heat exchanger consists of a total heat exchange element 11a and an element filter 11b. The total heat exchange element 11a is a rectangular element with rectangular faces. The element filter 11b is installed on two of the four sides. Relative to the length of the housing 10, one of the four corners formed by two adjacent sides of the element is arranged adjacent to the housing 10, another is arranged adjacent to the bypass ventilation duct 20, and the other two are arranged adjacent to one end of each of the partition plates 16 and 17.

[0066] The total heat exchange element 11a is made of paper, non-woven fabric, resin, etc., such as Figure 1 As shown in (b), the air supply channel 24, which forms part of the air supply duct 18, and the exhaust channel 25, which forms part of the exhaust duct 19, are constructed to overlap each other at different angles of approximately 90°. Therefore, in the total heat exchange element 11a, if the first layer is the air supply channel 24 from 0° to 180°, then the second layer is the exhaust channel 25 from 90° to 270°, and the third layer is the air supply channel 24 again from 0° to 180°, the air supply and exhaust flow channels are alternately formed in such a way that the air supply and exhaust flow channels are formed alternately.

[0067] Therefore, heat and moisture can pass through paper, while air cannot pass through paper, so the supply and exhaust of air will not mix.

[0068] However, due to the differential pressure generated during operation and gaps created during assembly, a portion of the exhaust gas leaks to the supply side of the total heat exchanger. Therefore, when people are present indoors, the actual CO2 concentration of the air supplied indoors (SA) is higher than the CO2 concentration of the outdoor air (OA).

[0069] In the supply air duct 18, an actuator such as a natural evaporation humidifier 26, an electric heater 27, and a direct expansion heat exchanger 28 is provided. These actuators are one example, and they can not be provided, one or two of them can be provided, or a device other than them can be provided. In addition, one or more of these devices and other devices can be provided.

[0070] The natural evaporation humidifier 26 includes a filter, a ceramic, or the like as a gasification portion and a water storage portion. The water storage portion stores water, and the gasification portion sucks the water from the water storage portion by capillary phenomenon, and performs humidification by naturally gasifying it. Here, a natural evaporation humidifier is exemplified, but it is not limited thereto, and a humidifier such as a steam type that has an electric heater, generates steam by heating water with the electric heater, and performs humidification, an ultrasonic type that forms mist by applying vibration to water with an ultrasonic generator, and sprays it to perform humidification, a hybrid type that has an electric heater and an ultrasonic generator, or the like can be used.

[0071] The direct expansion heat exchanger 28 is a heat exchanger or the like that directly exchanges heat with air used by the air conditioning device, and includes a heat transfer pipe (coil) through which a refrigerant that exchanges heat with the air flows.

[0072] A filter 29 as a trapping unit can be provided in the supply air duct 18. The filter 29 traps fine particles such as PM2.5, pollen, and yellow sand contained in the outdoor air. As the filter 29, a medium-high performance filter that mainly traps particles of 25 μm or more, a HEPA filter (High Efficiency Particulate Air filter) that mainly traps particles of 0.3 μm or more can be used. In addition, as the filter 29, in addition to these filters, a pre-filter that mainly traps particles of 50 μm or more can be provided.

[0073] Figure 1 The ventilation system illustrated has a control circuit 30 as a control unit, and is electrically connected to the supply air fan 21, the damper 22, the exhaust air fan 23, and an IAQ sensor described later as indicated by dotted lines. The control circuit 30 transmits and receives electric signals to and from these devices, and thereby can perform control of the air volume of the supply and exhaust air, switching between a total heat exchange mode and a normal ventilation mode, and the like. The total heat exchange mode is a ventilation mode in which the damper 22 is closed and the exhaust air is performed via the heat exchanger 11, and the normal ventilation mode is a ventilation mode in which the damper 22 is opened and the exhaust air is performed via the bypass duct 20 while bypassing the heat exchanger 11.

[0074] The control circuit 30 is configured to have the same structure as a control circuit mounted on an outdoor unit of the air conditioning device, and is configured to be able to perform the same control as the control circuit mounted on the outdoor unit of the air conditioning device. Figure 2As shown, it is provided with a CPU 40, a flash memory 41, a RAM (Random Access Memory) 42, a communication I / F 43, and a control I / F 44. The CPU 40 and the like are connected to a bus 45, and exchange information and the like via the bus 45.

[0075] The CPU 40 performs control of the whole ventilation system. The flash memory 41 stores programs, various data, and the like used in the control by the CPU 40. The RAM 42 provides a work area for the CPU 40. The communication I / F 43 receives information of air quality from the IAQ sensor. The control I / F 44 is connected to the supply air fan 21, the damper 22, and the exhaust air fan 23, and performs control of each unit.

[0076] Here, the control circuit 30 implements the air volume control and the ventilation mode switching by the CPU 40 reading out a program from the flash memory 41 and executing the program, but is not limited thereto, and dedicated hardware such as a circuit can be used to implement the air volume control and the like.

[0077] In order to implement the air volume control and the ventilation mode switching of the supply and exhaust air, information that becomes a reference for the control and the switching is required, and air quality is used as the information.

[0078] Conventionally, ventilation is implemented by measuring the CO2 concentration as air quality of indoor air using a CO2 sensor as an IAQ sensor, and controlling the air volume and the like so that the concentration does not exceed a target concentration. Therefore, the CO2 sensor is provided between the exhaust air introduction port 15 and the heat exchanger 11 in the exhaust air duct 19 or in the room.

[0079] In a case where the IAQ sensor such as a CO2 sensor is provided between the exhaust air introduction port 15 and the heat exchanger 11 in the exhaust air duct 19, the measured air quality becomes air quality of air after passing through the room, and thus it is not possible to measure air quality of outdoor air (OA). Therefore, even in a case where the CO2 concentration and PM2.5 and the like of the outdoor air increase, it is not possible to reduce the air volume or stop the fan.

[0080] Suppose that an IAQ sensor is provided near the outdoor, the supply air introduction port 12 of the supply air duct 18, it is possible to measure air quality of outdoor air (OA), but the air quality of the outdoor air (OA) does not indicate the actual air quality supplied to the room. This is because, due to the influence of the filter 29, leakage in the heat exchanger 11, and the like, the air quality supplied to the room is sometimes improved or deteriorated with respect to the air quality of the outdoor air (OA).

[0081] Thus, the air quality of the air (SA) supplied to the room is improved by the filter 29, and in a case where the air quality of the room can be sufficiently improved even if the air volume is maintained or reduced, control to increase the air volume is sometimes performed based on the air quality of the outdoor air (OA). Also, in a case where the air quality of the outdoor air (OA) is significantly reduced, control to reduce the air volume is sometimes performed even though the air quality of the air (SA) supplied to the room is maintained by the filter 29. Here, it cannot be said that the control is performed with an appropriate air volume or the like.

[0082] Also, in a case where the IAQ sensor is disposed between the exhaust air introduction port 15 and the heat exchanger 11 in the exhaust air duct 19 to perform control, the IAQ sensor is calibrated using outdoor air, but it is difficult to bring the IAQ sensor into contact with the outdoor air due to the disposition position, and thus various controls such as causing the supply air fan 21 and the exhaust air fan 23 to operate at the maximum air volume to generate an air flow from the supply air discharge port 14 to the exhaust air introduction port 15 via the room are required.

[0083] Thus, in the present system, the IAQ sensor 31 is not disposed between the exhaust air introduction port 15 and the heat exchanger 11 in the exhaust air duct 19, but is disposed between the heat exchanger 11 and the supply air discharge port 14 in the supply air duct 18, and is disposed at a position closer to the room side than the supply air fan 21, the natural evaporation type humidifier 26, the electric heater 27, and the direct expansion type heat exchanger 28 disposed therebetween. That is, the IAQ sensor 31 is disposed at a position close to the room.

[0084] Thus, it is possible to measure the CO2 concentration of the air (SA) actually supplied to the room after the outdoor air (OA) passes through the heat exchanger 11 and each actuator. Also, by opening the baffle 22 and causing the outdoor air (OA) to flow through the bypass duct 20, it is possible to perform calibration of the IAQ sensor 31.

[0085] The filter 29 is disposed between the heat exchanger 11 and the supply air introduction port 12 to capture fine particles such as PM2.5, pollen, and yellow sand contained in the outdoor air (OA). Also, the element filter 11b of the heat exchanger 11 is disposed on the supply air introduction port 12 side. Thus, the IAQ sensor 31 can measure the particle concentration in the air actually supplied to the room after the fine particles are captured by the filter 29 and the element filter 11b.

[0086] Thus, by measuring the air quality of the air actually supplied to the room, it is possible to appropriately control the supply and exhaust air to operate with an appropriate air volume and ventilation mode.

[0087] In order to perform appropriate control, it is important to what extent the filter 29 captures particles in the air, to what extent the heat exchanger 11 leaks. As an index indicating to what extent it is captured, filter capture efficiency can be used, and as an index indicating to what extent it is leaked, effective ventilation rate can be used.

[0088] Referring to Figure 3 , the relationship between filter capture efficiency and effective ventilation rate and control is explained. As Figure 3 indicated, in the ventilation system, the filter 29 is provided in the supply air duct 18, and the heat exchanger 11 is provided midway between the supply air duct 18 and the exhaust air duct 19 in a manner that spans both. The heat exchanger 11 is provided with an element filter 11b. The filter 29 and the element filter 11b capture fine particles contained in the outdoor air (OA). Thereby, fine particles are captured, and air (SA) that is cleaner than the outdoor air (OA) is sent to the indoor.

[0089] Depending on the meteorological conditions of the outdoor air (OA), in a situation where an alarm is issued that PM2.5 exceeds the 1-day average value of 35 μg / m 3 of Japan's environmental standards, or that yellow sand exceeds 200 μg / m 3 , in order to avoid such air from entering the indoor, it is preferable to reduce or stop the air volume of the supply air fan 21 and the exhaust air fan 23.

[0090] The filter 29, the element filter 11b are provided in the supply air duct 18, so even if air exceeding the above-described environmental standards is introduced, particles are captured by the filter 29 or the like, so the particle concentration of the air actually supplied to the indoor is lower than the above-described environmental standards, and control such as air volume, fan stoppage, or the like cannot be implemented at an appropriate timing.

[0091] However, by providing the IAQ sensor 31 at a position close to the indoor, the particle concentration of the air actually supplied to the indoor can be measured, so control such as air volume, fan stoppage, or the like can be implemented at an appropriate timing.

[0092] If the number of particles of fine particles contained in the outdoor air (OA) is set as N OA , and the number of particles of fine particles contained in the air (SA) supplied to the indoor by passing through the filter 29 alone through the bypass air duct 20, or by passing through the heat exchanger 11 and then passing through both the filter 29 and the element filter 11b is set as N SA , then the filter capture efficiency η is represented by the following formula 1.

[0093] [Formula 1]

[0094]

[0095] In a case where the filter is functioning normally, the collection efficiency indicates a value of a certain level or more, and thus the particle concentration of the outdoor air (OA) can be inferred from the measured value of the IAQ sensor 31. That is, the measured value of the IAQ sensor 31 varies depending on the particle concentration of the outdoor air (OA). Thus, it is possible to perform control to reduce the air volume in a case where the measured value of the IAQ sensor 31 is a first value or more, and to stop the fan in a case where the measured value of the IAQ sensor 31 is a second value or more. Note that this control is one example, and thus is not limited thereto.

[0096] These filters used in the ventilation system are given a collection efficiency of particles as a specification. Thus, it is possible to calculate the particle concentration of the SA from the above-described formula 1 using the given collection efficiency and the particle concentration of the outdoor air (OA) measured outdoors, and compare it with the particle concentration measured by the IAQ sensor 31, to determine the appropriateness of the measured value of the IAQ sensor 31.

[0097] The heat exchanger 11 allows heat and humidity to pass therethrough, but a portion of the exhaust air leaks to the supply air side due to a gap generated at the time of assembly, a differential pressure at the time of operation, or the like. This leakage amount can be expressed as an index of the effective ventilation rate (%) of the ventilation system as a product.

[0098] Let the CO2 concentration of the outdoor air (OA) be C OA Let the CO2 concentration of the air (SA) supplied to the indoor space after passing through the heat exchanger 11 be C SA Let the CO2 concentration of the air (RA) introduced from the exhaust air introduction port 15 before entering the heat exchanger 11 be C RA Then, the effective ventilation rate e is expressed by the following formula 2.

[0099] [Formula 2]

[0100]

[0101] For example, in a case where C OA is 400 ppm, C SA is 500 ppm, and C RA is 1000 ppm, the effective ventilation rate e is about 83% according to the above-described formula 2.

[0102] If the CO2 concentration in the indoor space increases, the CO2 concentration of the RA increases, and if the CO2 concentration of the outdoor air (OA) is substantially constant, the effective ventilation rate e is constant, and thus the CO2 concentration of the SA detected by the IAQ sensor 31 increases according to formula 2. The increase in the CO2 concentration of the SA is caused by the air leaked in the heat exchanger 11, and it is possible to control the air volume to increase by the amount of the leakage. Thus, it is possible to reduce the CO2 concentration in the indoor space and ensure comfort.

[0103] The control of the supply and exhaust air by the ventilation system also includes switching of the ventilation mode in addition to the air volume control by the supply fan 21 and the exhaust fan 23. Figure 4 is a diagram for explaining the full heat exchange and the ordinary ventilation, i.e., the mode switching. The ventilation system is provided with the damper 22, and by closing the damper 22, the air flows through the heat exchanger 11, and by opening the damper 22, the air flows by-passing the heat exchanger 11.

[0104] The ventilation mode can be switched depending on whether the full heat exchange is intended or not. In either mode selected, the filter 29 is provided on the supply air duct 18 on the side of the supply air inlet 12, and thus various particles in the outdoor air (OA) can be trapped, and the air quality of the air (SA) supplied to the indoor after trapping the various particles can be measured by the IAQ sensor 31.

[0105] The ventilation system can include an outdoor temperature sensor that detects the temperature of the outdoor air (OA), an outdoor humidity sensor that detects the relative humidity of the outdoor air (OA), an indoor temperature sensor that detects the temperature of the indoor, and an indoor humidity sensor that detects the relative humidity of the indoor. In this case, the temperature and the relative humidity of the outdoor air (OA) introduced from the supply air inlet 12 and the temperature and the relative humidity of the indoor air (RA) introduced from the exhaust air inlet 15 can be measured.

[0106] The control circuit 30 calculates the outdoor absolute humidity, the outdoor enthalpy, the indoor absolute humidity, and the indoor enthalpy based on the outdoor air temperature, the outdoor air relative humidity, the indoor temperature, and the indoor relative humidity measured by the respective sensors.

[0107] The control circuit 30 is provided with a storage section that stores the values of the indoor target temperature, the indoor target relative humidity, the indoor target absolute humidity, and the indoor target enthalpy. The control circuit 30 can switch the ventilation mode based on the indoor enthalpy, the outdoor enthalpy, and the indoor target enthalpy stored in the storage section.

[0108] For example, in the case of indoor target enthalpy < outdoor enthalpy < indoor enthalpy or outdoor enthalpy < indoor target enthalpy < indoor enthalpy, if the outdoor air with lower enthalpy than the indoor air is introduced without heat exchange, the indoor enthalpy can be decreased to approach the indoor target enthalpy, and thus the ordinary ventilation mode is set.

[0109] In the case of indoor enthalpy < outdoor enthalpy < indoor target enthalpy, if the outdoor air with enthalpy higher than the indoor air is introduced without heat exchange, the indoor enthalpy can be increased to approach the indoor target enthalpy, and thus the ordinary ventilation mode is set.

[0110] When the outdoor enthalpy is less than the indoor enthalpy and less than the indoor target enthalpy, outdoor air with a lower enthalpy than indoor air is introduced through heat exchange, which can suppress the decrease in indoor enthalpy and bring it closer to the indoor target enthalpy. Therefore, it is set to the total heat exchange mode.

[0111] When the indoor target enthalpy is less than the indoor enthalpy and less than the outdoor enthalpy, or when the indoor enthalpy is less than the indoor target enthalpy and less than the outdoor enthalpy, outdoor air with an enthalpy greater than that of indoor air is introduced through heat exchange. This can suppress the rise of indoor enthalpy and bring it closer to the indoor target enthalpy. Therefore, it is set to the total heat exchange mode.

[0112] The control circuit 30 compares various enthalpies and can switch the ventilation mode in a manner close to the indoor target enthalpy.

[0113] Here, the ventilation system is described with the following structure: a baffle 22 is provided on the exhaust inlet 15 side, so that air (RA) introduced from the exhaust inlet 15 through the opening and closing of the baffle 22 flows around the heat exchanger 11 through the bypass duct 20, or flows through the heat exchanger 11, but is not limited thereto. Therefore, it is also possible to configure the baffle 22 on the supply inlet 12 side, so that outdoor air (OA) flows around the heat exchanger 11 through the bypass duct 20, or flows through the heat exchanger 11, by opening and closing the baffle 22.

[0114] In ventilation systems equipped with total heat exchangers, in addition to using Figure 1 In addition to the system with the rectangular total heat exchange element 11a shown in (b), there is also a system with a rotating rotor. Figure 5 This is a diagram illustrating a structural example of a rotary rotor-type ventilation system. (and...) Figure 1 Similarly, the structure shown has an air supply inlet 12, an exhaust outlet 13, an air supply outlet 14, and an exhaust inlet 15, forming an air supply duct 18 and an exhaust duct 19. An air supply fan 21 is installed in the air supply duct 18, and an exhaust fan 23 is installed in the exhaust duct 19. In this example, a baffle 22 is provided in the air supply duct 18, and the air supply duct 18 and the exhaust duct 19 extend in a straight line.

[0115] A circular rotating total heat exchange element (rotor) 32 is provided as a heat exchanger 11 in the middle of the air supply duct 18 and the exhaust duct 19. The air supply side and the exhaust side of the rotor 32 are separated and rotate at a speed of tens of rpm. A bypass duct 20 is provided in the air supply duct 18 to bypass the heat exchanger 11 by opening a baffle 22.

[0116] Rotary rotor ventilation systems, such as Figure 5 When the baffle 22 is closed as shown in (a), as Figure 5As shown in (b), indoor air (RA) is exhausted to the outside as EA through the lower half of the rotating rotor 32, while outdoor air (OA) is supplied to the room as SA through the upper half of the rotor 32. During heating, the heat and moisture contained in RA are continuously recovered by the rotor 32, and the recovered heat and moisture are continuously supplied to SA. Furthermore, during cooling, the heat and moisture contained in OA are continuously recovered by the rotor 32, and unwanted heat and moisture can be continuously removed from SA.

[0117] like Figure 5 As shown in (c), when the baffle 22 is opened, the rotation of the rotor 32 is stopped, air is supplied through the bypass ventilation duct 20, and exhaust is carried out through the lower half of the stationary rotor 32.

[0118] Reference Figure 6 An example of controlling the supply and exhaust of the ventilation system will be described. Using a switch, remote control, or similar means, the ventilation system is activated, and control begins from step 100 by connecting the power supply. In step 101, the air quality of SA is measured using the IAQ sensor 31. In step 102, it is determined whether the supply fan 21 and exhaust fan 23 need to be activated.

[0119] If the supply air fan 21 and exhaust fan 23 are already running, there is no need to start them. Furthermore, if the air quality measured by the IAQ sensor 31 is below the target value indicating sufficient air quality to ensure comfort, there is no need to start them. For example, if the CO2 concentration in the RA is above 1000 ppm, and the supply air fan 21 and exhaust fan 23 have not yet been started, it can be determined that these fans need to be started. The CO2 concentration in the RA can be estimated based on the CO2 concentration measured by the IAQ sensor 31 and the effective ventilation rate e of the heat exchanger 11.

[0120] If it is determined in step 102 that it needs to be started, proceed to step 103 and start the air supply fan 21 and the exhaust fan 23.

[0121] In step 104, based on the measurement results of step 101, it is determined whether the airflow needs to be changed. Whether the airflow needs to be changed can be determined based on the measurement results of the IAQ sensor 31, such as whether the CO2 concentration is above a predetermined value and whether the particle concentration is above the aforementioned first value. These are just examples, and therefore are not limited to this.

[0122] When it is determined in step 104 that the change is required, the process proceeds to step 105, where the air volume is changed. When the CO2 concentration is increased, it is considered that the CO2 concentration of the air leaked from the heat exchanger 11 is increased, and therefore, in order to introduce more outdoor air (OA) having a low CO2 concentration, indoor air having a high CO2 concentration is exhausted, and the air volume can be increased.

[0123] When the particle concentration is increased, it is considered that the particle concentration of the outdoor air (OA) is increased. In this case, in order to reduce the amount of the outdoor air (OA) introduced into the indoor, the air volume can be reduced.

[0124] In step 106, it is determined whether or not the air supply fan 21 and the air exhaust fan 23 are stopped, based on the measurement result of step 101. When the particle concentration is increased to be equal to or more than the second value described above, it is determined that the air supply fan 21 and the air exhaust fan 23 are stopped.

[0125] When it is determined in step 106 that the air supply fan 21 and the air exhaust fan 23 are not stopped, the process returns to step 101, and the control is repeated. On the other hand, when it is determined in step 106 that the air supply fan 21 and the air exhaust fan 23 are stopped, the process proceeds to step 107, where the air supply fan 21 and the air exhaust fan 23 are stopped, and the process returns to step 101.

[0126] Figure 6 The control shown continues until the power supply of the ventilation system is turned off or an error occurs. The power supply is turned off by instructing the stop of the ventilation system using a switch, a remote controller, or the like.

[0127] Reference Figure 7 and Figure 8 An example of construction when the ventilation system is installed will be described. Figure 7 A first example of construction is shown in FIG. 2, Figure 8 A second example of construction is shown in FIG. 3. In Figure 7 In the example of construction shown in FIG. 2, a duct 50 and a duct 51 that are continuous with the indoor are provided on the back surface of the ceiling, and the ducts 50 and 51 are connected to the air supply outlet 14 and the air exhaust inlet 15 of the ventilation system, respectively.

[0128] The ventilation system sucks the outside air (OA) using the air supply fan 21, and supplies the air to the indoor through the duct 50 connected to the air supply outlet 14. The IAQ sensor 31 is provided in the duct 50 at a position close to the indoor. The IAQ sensor 31 can also be provided in the air supply duct 18 of the ventilation system at a position close to the air supply outlet 14, but since the duct 50 can also leak, it is preferable to be provided in the duct 50 at a position close to the indoor as much as possible.

[0129] In a case where the IAQ sensor 31 is provided in the duct 50 away from the ventilation system, in order to communicate between the IAQ sensor 31 and the ventilation system, wired communication can be performed by connection through a cable or the like, or wireless communication can be performed by wireless connection.

[0130] In Figure 8 In the construction example shown, the supply air blowout port 14 is connected to the indoor unit 52 of the air conditioning device through the duct 53, and the supply air mixes with the blowout air blown out by the indoor unit 52. In such a case, the IAQ sensor 31 can be provided on the indoor unit 52 side in the duct 53. The IAQ sensor 31 can also be provided at the air blowout port that blows out mixed air in which the blowout air of the indoor unit 52 and the supply air are mixed. In a case where the IAQ sensor 31 is provided near the indoor unit 52 or in the indoor unit 52, power for causing the IAQ sensor 31 to operate can be supplied from the indoor unit 52.

[0131] The communication of the IAQ sensor 31 with the ventilation system is the same as Figure 7 In the construction example shown, the supply air blowout port 14 is connected to the indoor unit 52 of the air conditioning device through the duct 53, and the supply air mixes with the blowout air blown out by the indoor unit 52. In such a case, the IAQ sensor 31 can be provided on the indoor unit 52 side in the duct 53. The IAQ sensor 31 can also be provided at the air blowout port that blows out mixed air in which the blowout air of the indoor unit 52 and the supply air are mixed. In a case where the IAQ sensor 31 is provided near the indoor unit 52 or in the indoor unit 52, power for causing the IAQ sensor 31 to operate can be supplied from the indoor unit 52.

[0132] In this way, the IAQ sensor 31 can also be provided in the indoor unit 52, and ventilation can be performed at the same time as refrigeration and heating operation, and thus, in the present application, not only a ventilation system but also an air conditioning device including the indoor unit 52, the outdoor unit, and the ventilation system can be provided.

[0133] Figure 9 is a graph that explains the maintenance (servicing) timing of the filter 29 and the elements of the heat exchanger 11. If the filter 29 and the element filter 11b of the heat exchanger 11 deteriorate, the particle concentration or the particle amount of the air quality of SA measured by the IAQ sensor 31 increases.

[0134] Figure 9 is a graph that is a time series data in which the horizontal axis is elapsed time and the vertical axis is the CO2 concentration and the particle amount. As Figure 9 shown, in a case where the filter 29 and the element filter 11b do not deteriorate, the particle amount moves within a certain range. However, if they deteriorate, they deviate from the range and increase with the passage of time.

[0135] Thus, data in which the particle amount deviates from the range to reach an arbitrarily set value surrounded by a circle can be data at the time of an abnormality. The period shown by the data at the time of the abnormality becomes a period in which servicing is required. According to Figure 9As shown in the chart, CO2 concentration and particle quantity begin to increase, and before reaching the period requiring maintenance, they continue to increase at roughly the same rate over a specified period of time.

[0136] Maintenance required during such periods Figure 10 As shown, during the learning period, maintenance is required based on the time series data survey. Figure 9 The tendency shown. In Figure 10 The data shows a tendency for the measured values ​​to rise continuously at a certain rate, indicating that the maintenance period is approaching.

[0137] When time series data shows such a trend, it is possible to approximate the value of the measured data from its initial rise to the present by using a straight line, and then interpolate to predict the period when the value of the abnormal value is predicted as the period that needs maintenance. The calculation for this prediction can be performed within the control circuit 30, or it can be performed in the remote monitoring system, cloud system, etc., which are external systems for remotely monitoring the ventilation system.

[0138] In addition, the filter does not deteriorate rapidly, so by collecting a few data points a day and averaging them, the memory capacity can be kept relatively small.

[0139] If the total heat exchange element 11a deteriorates, the leakage will increase, and the CO2 concentration measured by the IAQ sensor 31 will increase. Therefore, the CO2 concentration will also deviate from a certain range. The time when the CO2 concentration reaches an abnormal value is taken as the period when the total heat exchange element 11a needs maintenance. This can be predicted by interpolating the time series data measured by the IAQ sensor 31.

[0140] In addition, the effective ventilation rate e can be calculated based on the CO2 concentrations of RA and OA to confirm whether the value has not changed, i.e. whether it is within a certain range. Periods in which changes occur and reach abnormal values ​​are predicted as periods requiring maintenance.

[0141] Furthermore, the timing of maintenance for filters and total heat exchange components can be predicted by extrapolation from data collected during operation. Alternatively, machine learning can be used with training data to predict maintenance needs using a fully learned model. Moreover, using a fully learned model allows for more accurate predictions of when maintenance is required.

[0142] As explained above, according to the present control, compared with the case where the IAQ sensor is provided between the heat exchanger 11 and the exhaust air introduction port 15 in the exhaust air duct 19 in order to measure the air quality of the RA in the related art, it is possible to measure the air quality actually supplied to the room, and it is possible to operate in the appropriate air volume control, ventilation mode. In addition, it is possible to detect the deterioration of the filter, the total heat exchange element, the leakage, and it is also possible to perform appropriate maintenance prediction.

[0143] Thus far, the ventilation system, the air conditioning device, and the control method of the present application have been described in detail using the above-described embodiments, but the present application is not limited to the above-described embodiments, and can be changed within a range that can be thought of by those skilled in the art, such as other embodiments, additions, changes, deletions, and the like, and in any of the modes, as long as the function and effect of the present application are exerted, it is included in the scope of the present application.

Claims

1. A ventilation system for controlling supply and exhaust air, characterized in that The ventilation system includes: a supply air duct provided with a supply unit that supplies outdoor air into a room; an exhaust air duct provided with an exhaust unit that exhausts air in the room to the outdoor; a heat exchanger disposed midway between the supply air duct and the exhaust air duct, which performs at least heat exchange between the air in the room and the outdoor air; a measurement unit disposed in a position close to the room, which measures the air quality of the outdoor air after passing through the heat exchanger, which is supplied by the supply unit into the room, and further measures the concentration of carbon dioxide in the air; and a control unit that controls the supply and exhaust performed by the supply unit and the exhaust unit based on the measurement result of the measurement unit measuring the concentration of carbon dioxide. The control unit predicts the maintenance period of the heat exchanger based on the time variation of the measurement result.

2. The ventilation system according to claim 1, wherein the ventilation system includes: a bypass air duct that bypasses the heat exchanger; and an opening and closing unit that opens and closes in correspondence with a ventilation mode so as to open either of an inlet of the bypass air duct and an inlet for passing through the heat exchanger and close the other, the control unit performs switching control of the ventilation mode based on the measurement result.

3. The ventilation system according to claim 1 or 2, wherein a trapping unit that traps particles contained in the outdoor air is included between a supply air inlet through which the outdoor air is introduced into the supply air duct and the heat exchanger.

4. The ventilation system according to claim 3, wherein the measurement unit further measures the concentration of particles in the air.

5. The ventilation system according to claim 1 or 2, wherein at least one of a humidifier, a heater, and a direct expansion heat exchanger is included on the exhaust side of the supply unit between a supply air outlet through which the outdoor air in the supply air duct is blown out to the room and the heat exchanger, the measurement unit is disposed in a position closer to the room side than the at least one of the humidifier, the heater, and the direct expansion heat exchanger.

6. The ventilation system according to claim 1 or 2, wherein the measurement unit is disposed in a position close to the room in a pipe that connects the room and a supply air outlet through which the ventilation system blows out the outdoor air.

7. The ventilation system according to claim 1 or 2, wherein a supply air outlet through which the ventilation system blows out the outdoor air is connected to an indoor unit of an air conditioning device through a pipe, and the measurement unit is disposed in a position close to an air outlet of the indoor unit.

8. The ventilation system according to claim 1 or 2, wherein the control unit transmits the measurement result to an external system in order to predict the maintenance period of the heat exchanger.

9. An air conditioning device including an indoor unit, an outdoor unit, and a ventilation system connected to the indoor unit, wherein the ventilation system includes: a supply air duct provided with a supply unit that supplies outdoor air into a room; an exhaust air duct provided with an exhaust unit that exhausts air in the room to the outdoor; a heat exchanger disposed midway between the supply air duct and the exhaust air duct, which performs at least heat exchange between the air in the room and the outdoor air; a measurement unit disposed in a position close to the room, which measures the air quality of the outdoor air after passing through the heat exchanger, which is supplied by the supply unit into the room, and further measures the concentration of carbon dioxide in the air; and a control unit that controls the supply and exhaust performed by the supply unit and the exhaust unit based on the measurement result of the measurement unit measuring the concentration of carbon dioxide. a supply air duct including a supply air unit that supplies outdoor air to an indoor space; an exhaust air duct including an exhaust air unit that exhausts indoor air to the outdoor space; a heat exchanger that is disposed midway between the supply air duct and the exhaust air duct and performs at least heat exchange between the indoor air and the outdoor air; a measurement unit that is disposed near an air outlet of the indoor unit and measures an air quality of the outdoor air after passing through the heat exchanger, which is supplied to the indoor space by the supply air unit, the measurement unit further measuring a carbon dioxide concentration in the air; and a control unit that controls supply and exhaust of air by the supply air unit and the exhaust air unit based on a measurement result of the measurement unit measuring the carbon dioxide concentration. The control unit predicts a maintenance period of the heat exchanger based on a time change in the measurement result.

10. A method of controlling supply and exhaust of air by a ventilation system, the ventilation system including: a supply air duct including a supply air unit that supplies outdoor air to an indoor space; an exhaust air duct including an exhaust air unit that exhausts indoor air to the outdoor space; a heat exchanger that is disposed midway between the supply air duct and the exhaust air duct and performs at least heat exchange between the indoor air and the outdoor air; a measurement unit that is disposed near an air outlet of the indoor unit and measures an air quality of the outdoor air after passing through the heat exchanger, which is supplied to the indoor space by the supply air unit, the measurement unit further measuring a carbon dioxide concentration in the air; and a control unit that controls supply and exhaust of air by the supply air unit and the exhaust air unit based on a measurement result of the measurement unit measuring the carbon dioxide concentration. The control unit predicts a maintenance period of the heat exchanger based on a time change in the measurement result. ​ ​ ​ ​

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