Patent Publication Number: US-11378298-B2

Title: Control method for ventilation apparatus

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a U.S. National Stage Application under 35 U.S.C. § 371 of PCT Application No. PCT/KR2018/008875, filed Aug. 6, 2018, which claims priority to Korean Patent Application No. 10-2017-0099761, filed Aug. 7, 2017, whose entire disclosures are hereby incorporated by reference. 
     TECHNICAL FIELD 
     The present invention relates to a control method of a ventilation apparatus and, more particularly, to a control method of a ventilation apparatus which is capable of reducing an operation time of a dry mode in which a surface of a desiccant heat exchanger is dried for dehumidification. 
     BACKGROUND ART 
     In general, a ventilation apparatus refers to an apparatus which discharges contaminated indoor air while suctioning fresh and clean outdoor air to be supplied to an indoor space. 
     An air conditioner without a ventilating function cools or heats indoor air while causing the indoor air to circulate. 
     An air conditioner into which outdoor air is not introduced filters indoor air through a filter or the like, but, if air conditioning is performed only with indoor air, the quality of the indoor air may be slowly deteriorated. 
     Recently, there are increasing cases in which a ventilation capable of suctioning outdoor air and discharging indoor air is installed in combination with an air conditioner having a cooling function and a heating function. 
     Meanwhile, a ventilation apparatus according to an existing technology employs a desiccant heat exchanger of which surface is desiccant-coated for indoor dehumidification and humidification. 
     However, if there is a large amount of moisture absorbed onto the surface of the desiccant heat exchanger used for indoor dehumidification, it dampens dehumidification efficiency so it is necessary to dry the surface of the desiccant heat exchanger frequently. 
     In addition, an existing technology works such that the surface of the desiccant heat exchanger is naturally dried while operation in a dehumidification mode stops, and, in this case, more time is required to dry the surface of the desiccant heat exchanger and an occupant may not sufficiently feel satisfied with the dehumidification. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     The present invention has been made in view of the above problems, and it is one object of the present invention to provide a control method of a ventilation apparatus, the method by which a dry mode operation time of a desiccant heat exchanger is remarkably reduced, thereby improving product reliability. 
     Solution to Problem 
     In accordance with an embodiment of the present invention, the above and other objects can be accomplished by the provision of a control method of a ventilation apparatus, the method including: a determination step in which outdoor temperature and humidity and indoor temperature and humidity are measured and whether the measured outdoor temperature and humidity and the measured indoor temperature and humidity are equal to or greater than a set temperature and a set humidity; and a drying operation step in which, when the outdoor temperature and humidity and the indoor temperature and humidity, measured in the determination step, reach the set temperature and the set humidity (hereinafter, referred to as a “set condition”), a first desiccant heat exchanger and a second heat exchanger operate in a dry mode, wherein the first desiccant heat exchanger is provided in a first common passage, through which indoor space air (hereinafter, referred to as “indoor air”) or outdoor space air (hereinafter, referred to as “outdoor air”) flows, to absorb or desorb moisture, and the second desiccant heat exchanger is provided in a second common passage, which is separate from the first common passage, and through which indoor air or outdoor air flows, to absorb or desorb moisture in air, wherein the drying operation step includes: a heat exchanger control step in which a refrigerant is switched from a compressor to be supplied, so that one desiccant heat exchanger needed to be dried (hereinafter, referred to as a “condenser-type desiccant heat exchanger) out of the first desiccant heat exchanger and the second desiccant heat exchanger acts as a condenser while the other desiccant heat exchanger not needed to be dried (hereinafter, referred to as an “evaporator-type desiccant heat exchanger) acts as an evaporator: and a flow rate control step which is performed simultaneously with the heat exchanger control step, and in which a flow rate of air passing through the condenser-type desiccant heat exchanger (hereinafter, referred to as a “first flow rate”) is controlled to be less than a flow rate of air passing through the evaporator-type desiccant heat exchanger (hereinafter, referred to as a “second flow rate”). 
     The heat exchanger control step may be a step in which a refrigerant discharged from the compressor is supplied first to the condenser-type desiccant heat exchanger using a refrigerant switching valve. 
     The heat exchanger control step may be a step in which, when the set condition is satisfied, the first desiccant heat exchanger and the second desiccant heat exchanger are compared in terms of a percentage of moisture absorbed onto a surface (hereinafter, referred to as a “moisture absorption rate”) and a refrigerant discharged from the compressor is supplied first to the condense-type desiccant heat exchanger using a refrigerant switching valve. 
     The heat exchanger control step may be a step in which a desiccant heat exchanger of which the moisture absorption rate is high in the first desiccant heat exchanger and the second desiccant heat exchanger is determined to be the condenser-type desiccant heat exchanger. 
     The flow rate control step may be a step in which the first flow rate and the second flow rate are controlled by adjusting a rotation amount of a plurality of dampers composed of a plurality of shutter plates which rotates about horizontal axes relative to a plurality of chambers provided to suction indoor air or outdoor air into the first common passage and the second common passage or discharge the indoor air or the outdoor air to the first common passage and the second common passage. 
     The plurality of dampers may include an indoor suction damper provided in an indoor suction chamber into which indoor air is suctioned toward the first common passage or the second common passage, an indoor discharge damper provided in an indoor discharge chamber through which air is discharged to an indoor space from the first common passage or the second common passage, an outdoor suction damper provided in an outdoor suction chamber into which outdoor air is suctioned toward the first common passage or the second common passage, and an outdoor discharge damper provided in an outdoor discharge chamber through which air is discharged to an outdoor space from the first common passage or the second common passage, and the flow rate control step may be performed such that the indoor suction damper and the indoor discharge damper are controlled to be closed, whereas the outdoor suction damper and the outdoor discharge damper are controlled to be opened. 
     The flow rate control step may be performed such that, when it is assumed that the condenser-type desiccant heat exchanger is provided in the first common passage and the evaporator-type desiccant heat exchanger is provided in the second common passage, the outdoor suction damper and the outdoor discharge damper in the second common passage are controlled to be fully opened while the outdoor suction damper and the outdoor discharge damper in the first common passage are controlled to be opened to an extent where the first flow rate is less than the second flow rate. 
     Advantageous Effects of Invention 
     The advantageous effects of a control method of a ventilation apparatus according to the present invention are as follows. 
     First, as moisture absorbed onto a surface of a desiccant heat exchanger is dried using a high-temperature and high-pressure refrigerant discharged from a compressor, it is possible to reduce a dry mode operation time considerably. 
     Second, as a plurality of dampers are adjusted during the dry mode of the desiccant heat exchanger so as to prevent humid air from coming inside an indoor space, it is possible to prevent an occupant from feeling uncomfortable. 
     Third, as moisture as less as possible is controlled to be absorbed onto a surface of an evaporator-type desiccant heat exchanger, it is possible to improve operation efficiency of the dry mode. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of an example of a ventilation apparatus which implements a control method of a ventilation apparatus according to the present invention. 
         FIG. 2  is a plan view of  FIG. 2 . 
         FIG. 3  is a conceptual airflow diagram of a control method of a ventilation apparatus according to the present invention. 
         FIG. 4  is a conceptual refrigerant flow diagram of  FIG. 3 . 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, an embodiment of a ventilation apparatus according to the present invention will be described in detail with reference to the accompanying drawings. 
     In describing the present invention, well-known functions or constructions will not be described in detail since they may unnecessarily obscure the understanding of the present invention. It should be noted that even if the same terms are used but they indicate different components, they are not given the same reference numerals. 
     The terms described hereafter are terms defined in consideration of the functions in the present disclosure and may be change in accordance with the intention of a user, such as an experimenter and a measurer, and a custom, so the definition should be based on the entire description of the present disclosure. 
     Terms used in the specification, ‘first’, ‘second’, etc., may be used to describe various components, but the components are not to be construed as being limited to the terms. The terms are used to distinguish one component from another component. For example, the ‘first’ component may be named the ‘second’ component, and vice versa, without departing from the scope of the present invention. The term ‘and/or’ includes a combination of a plurality of items or any one of a plurality of terms. 
     Terms used in the present specification are used only in order to describe specific exemplary embodiments rather than limiting the present invention. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. It must be understood that the terms defined by the dictionary are identical with the meanings within the context of the related art, and they should not be ideally or excessively formally defined unless the context clearly dictates otherwise. 
     Further, unless explicitly described otherwise, “comprising” any components will be understood to imply the inclusion of other components rather than the exclusion of any other components. 
       FIG. 1  is a perspective view illustrating an example of a ventilation apparatus which implements a control method of a ventilation apparatus according to the present disclosure,  FIG. 2  is a plan view of  FIG. 1 ,  FIG. 3  is a conceptual airflow diagram of a control method of a ventilation apparatus according to the present disclosure, and  FIG. 4  is a conceptual refrigerant flow diagram of  FIG. 3 . 
     An example of a ventilation apparatus which implements a control method of a ventilation apparatus according to the present disclosure will be described prior to the control method. 
     Referring to  FIGS. 1 and 2 , an example of a ventilation apparatus according to the present disclosure includes a case  10 , an outdoor discharge fan  20  which is installed in the case  10  and discharges air to an outdoor space, an indoor discharge fan  30  which is installed in the case  10  and discharges air to an indoor space, and an air conditioning unit  40  which is installed in the case  10  and perform air conditioning on an airflow. 
     The case  10  includes a first common passage  11  through which indoor space air (hereinafter, referred to as indoor air) or outdoor space air (hereinafter, referred to as outdoor air) flows, a second common passage  12  which is positioned above the first common passage  11 , an indoor suction chamber  52  which is connected to the first common passage  11  and the second common passage  12  and into which indoor air is suctioned, an indoor discharge chamber  54  which is connected to the first common passage  11  and the second common passage  12  and from which air is discharged into an indoor space, an outdoor suction chamber  56  which is connected to the first common passage  11  and the second common passage  12  and into which outdoor air is suctioned, and an outdoor discharge chamber  58  which is connected to the first common passage  11  and the second common passage  12  and from which air is discharged to an outdoor space. 
     Hereinafter, for convenience of explanation, introducing indoor air through the indoor suction chamber  52  is referred to as “ventilating”, discharging air into an indoor space through the indoor discharge chamber  54  is referred to as “supplying”, introducing outdoor air through the outdoor suction chamber  56  is referred to as “intaking”, and discharging air to an outdoor space through the outdoor discharge chamber  58  is referred to as “exhausting”. 
     The first common passage  11  and the second common passage  12  are formed by an upper and lower side separation plate  13 . The first common passage  11  may be formed under the upper and lower side separation plate  13 , and the second common passage  12  may be formed above the upper and lower side separation  13 . 
     A suction guide  90  may be provided in each of the first common passage  11  and the second common passage  12 . The suction guide  90  guides ventilated air or intake air, which is suctioned through the indoor suction chamber  52  and the outdoor suction chamber  56 , to desiccant heat exchangers  41  and  42  of the air conditioning unit  40 . 
     In addition, an indoor suction damper  62 , an indoor discharge damper  64 , an outdoor suction damper  66 , and an outdoor discharge damper  68  are respectively disposed in the indoor suction chamber  52 , the indoor discharge chamber  54 , the outdoor suction chamber  56 , and the outdoor discharge chamber  58  so as to control an air flow with the first common passage  11  or the second common passage  12 . 
     Thus, the above described plurality of dampers  62  to  68  may be respectively provided in four chambers of the first common passage  11  and respectively provided in four chambers of the second common passage  12 , and thus, it is desirable that eight chambers in total are provided 
     Meanwhile, as illustrated in  FIG. 4 , the air conditioning unit  40  includes a compressor  45 , desiccant heat exchangers  41  and  42  respectively provided in the first common passage  11  and the second common passage  12 , an expansion valve  43 , and a refrigerant switching valve  44 . 
     In this case, for convenience of explanation, out of the desiccant heat exchangers  41  and  42 , a desiccant heat exchanger provided in the first common passage  11  will be referred to as a “first desiccant heat exchanger  41 ”, and a desiccant heat exchanger provided in the second common passage  12  will be referred to as a “second desiccant heat exchanger”. 
     That is, the first desiccant heat exchanger  41  may be disposed inside the first common passage  11  positioned under the upper and lower side separation plate  13 , and the second desiccant heat exchanger  42  may be disposed inside the second common passage  12  positioned above the upper and lower side separation plate  13 . 
     In this case, the air conditioning unit  40  may be a heat pump capable of operating in a cooling cycle and a heating cycle. Thus, when the first desiccant heat exchanger  41  acts as a condenser due to switching of a flow by the refrigerant switching valve  44 , the second desiccant heat exchanger  42  acts as an evaporator, and, when the first desiccant heat exchanger  41  acts as an evaporator, the second desiccant heat exchanger  42  acts as a condenser. The operating mechanism of the air conditioner  40  is a general technology well known for a person skilled in the art, and thus, a detailed description thereof will be omitted. 
     In particular, the first desiccant heat exchanger  41  and the second desiccant heat exchanger  42  may be arranged to partition the first common passage  11  and the second common passage  12  into a suction side passage, in which the indoor suction chamber  52  and the outdoor suction chamber  56  are provided, and a discharge side passage in which the indoor discharge chamber  54  and the outdoor discharge chamber  58 . 
     Meanwhile, surfaces of the desiccant heat exchangers  41  and  42  are desiccant coated to absorb moisture in the air. The desiccant coating is made of a material capable of absorbing moisture in the air and dissipating the absorbed moisture into the air upon application of heat, and such a material is generally used by a person skilled in the art and thus detailed description thereof will be omitted. 
     An example of the ventilation apparatus configured as above has a refrigerant flow as illustrated in  FIG. 4 . 
     That is, high-temperature and high-pressure refrigerant discharged from the compressor  45  may be switched by the refrigerant switching valve  44  and then flow into the first desiccant heat exchanger  41  provided in the first common passage  11  or may flow into the second desiccant heat exchanger  42  provided in the second common passage  12 . 
     While passing through the first desiccant heat exchanger  41 , the refrigerant flown into the first desiccant heat exchanger  41  let the first desiccant heat exchanger  41  act as a condenser (for this reason, hereinafter referred to as a “condenser-type desiccant heat exchanger”, when needed), and the refrigerant supplies moisture absorbed onto the surface of the first desiccant heat exchanger  41  to the air passing through the first desiccant heat exchanger  41 , by which the moisture is desorbed. 
     The refrigerant condensed while passing through the first desiccant heat exchanger  41  is expanded while passing through the expansion valve  43 , and then flows into the second desiccant heat exchanger  42  provided in the second common passage  12 . 
     While passing through the second desiccant heat exchanger  42 , the refrigerant flown to the side of the second desiccant heat exchanger  42  lets the second desiccant heat exchanger  42  to act as an evaporator  42  (for this reason, hereinafter referred to as an “evaporator-type desiccant heat exchanger”), and the refrigerant causes moisture in the air passing through the second desiccant heat exchanger  42  to be absorbed on the surface of the second desiccant heat exchanger  42 . 
     The refrigerant passing through the second desiccant heat exchanger  42  may be recovered to the compressor  45  by passing through a not-illustrated accumulator. 
     The following is description about a ventilation mode, a dehumidification mode, and a humidification mode using an example of a ventilation apparatus with reference to  FIGS. 3 and 4 . 
     First, in the dehumidification mode, when a dehumidification command signal is received, the above-described dampers  62  to  68  provided in the first common passage  11  are adjusted so as to exhaust humid indoor air to an outdoor space, and the above-described dampers  62  to  68  provided in the second common passage  12  are adjusted so as to supply outdoor air to an indoor space through the second common passage  12 , wherein moisture in the outdoor air is absorbed onto the surface of the second desiccant heat exchanger  42  which acts as an evaporator so that dry air is supplied to the indoor space. 
     More specifically, the above-described dampers  62  to  68  provided in the first common passage  11  are controlled such that the indoor suction damper  62  and the outdoor discharge damper  68  are opened and the indoor discharge damper  64  and the outdoor suction damper  66  are closed, and the above-described dampers  62  to  68  provided in the second common passage  12  are controlled such that the outdoor suction damper  66  and the indoor discharge damper  64  are opened and the outdoor discharge damper  68  and the indoor suction damper  62  are closed. 
     Next, in the humidification mode, when a humidification command signal is received, the above-described dampers  62  to  68  provided in the first common passage  11  are adjusted so as to supply outdoor air to an indoor space through the first common passage  11 , wherein moisture is supplied to the outdoor air passing through the first desiccant heat exchanger  41 , acting as a condenser, so that humid air is supplied to the indoor space, and the above-described dampers  62  to  68  provided in the second common passage  12  are adjusted so that relatively dry indoor air is exhausted to an outdoor space through the second common passage  12 . 
     More specifically, the above-described dampers  62  to  68  provided in the first common passage  11  are controlled such that the outdoor suction damper  66  and the indoor discharge damper  64  are opened and the outdoor discharge damper  68  and the indoor suction damper  62  are closed, and the above-described dampers  62  to  68  provided in the second common passage  12  are controlled such that the indoor suction damper  62  and the outdoor discharge damper  68  are opened and the indoor discharge damper  64  and the outdoor suction damper  66  are closed. 
     In the dehumidification mode, in the case of exhausting indoor air to an outdoor space, when a flow of refrigerant is switched by the refrigerant switching valve  44 , the first desiccant heat exchanger  41  in the first common passage  11 , while acting as a condenser, desorbs moisture absorbed onto the surface of the first desiccant heat exchanger  41  and exhausts the desorbed moisture for the sake of later indoor dehumidification. 
     In contrast, in the humidification mode, in the case of exhausting indoor air to an outside space, when a flow of refrigerant is switched by the refrigerant switching valve  44 , the second desiccant heat exchanger  42  in the second common passage  12 , while acting as an evaporator, absorbs a sufficient amount of moisture from indoor air, exhausted from the second desiccant heat exchanger  42 , for the sake of indoor humidification. 
     Meanwhile, the ventilation mode may be implemented in a manner in which, while the compressor  45  is power off, the dampers  62  to  68  in the first common passage  11  and the dampers  62  to  68  in the second common passage  12  are controlled properly, so that outdoor air is supplied to an indoor space through one of the first common passage  11  and the second common passage  12  and, at the same time, indoor air is exhausted to an outdoor space through the other thereof. 
     The ventilation apparatus according to the above-described embodiment provides an occupant with a continuous dehumidified or humidified environment by properly controlling the above-described dampers  62  to  68  while alternatively using the two heat exchangers  41  and  42  by switching the refrigerant switching valve  44  according to a percentage of moisture absorbed onto the surfaces of the first desiccant heat exchangers  41  and the second desiccant heat exchanger  42 . 
     For example, in the dehumidification mode for dehumidifying an indoor space, when the first desiccant heat exchanger  41  in the first common passage  11  is set as an evaporator-type desiccant heat exchanger, moisture is absorbed using the first desiccant heat exchanger  41  and moisture is desorbed using the second desiccant heat exchanger  42  in the second common passage  12 . 
     In this case, before a percentage of absorption of moisture of the first desiccant heat exchanger reaches a saturated state, the refrigerant switching valve  44  is switched so that the second desiccant heat exchanger  42  in the second common passage  12  acts as an evaporator-type desiccant heat exchanger whereas at the same time the first desiccant heat exchanger  41  in the first common passage  11  acts as a condenser-type desiccant heat exchanger. In addition, the dampers  62  to  68  in the first common passage  11  are adjusted to exhaust indoor air to an outside space whereas at the same time the dampers  62  to  68  in the second common passage  12  are adjusted to supply outdoor air to an indoor space, so that moisture of the outdoor air is absorbed onto the surface of the second desiccant heat exchanger  42  and hence dry air is supplied to the indoor space. 
     In this case, in the dehumidification mode, for example, when a percentage of moisture absorbed onto the surface of the first desiccant heat exchanger  41  acting as an evaporator-type desiccant heat exchanger reaches a saturated state, an existing method is implemented in a manner of stopping operation of the compressor  45  and then operating the ventilation apparatus only in the above-described ventilation mode to thereby execute a dry mode. 
     However, when the outdoor space is hot and humid and the indoor space is cold and humid, a percentage of moisture absorbed onto the evaporator-type desiccant heat exchanger is high but a percentage of moisture desorbed therefrom is low, and therefore, a dry mode operation time increases significantly. If the evaporator-type desiccant heat exchanger is not dried well, the dehumidification mode is executed while there is a great amount of absorbed moisture, and thus, dehumidification performance is naturally deteriorated. 
     A control method of a ventilation apparatus according to the present invention proposes the following embodiment to solve the above-described existing problem. 
     That is, as illustrated in  FIGS. 3 and 4 , a control method of a ventilation apparatus according the present disclosure includes: a determination step in which indoor temperature and humidity and outdoor temperature and humidity are measured and whether the measured indoor temperature and humidity and the measured outdoor temperature and humidity are equal to or greater than a set temperature and a set humidity is determined; and a drying operation step in which, when it is determined in the determination step that the measured indoor temperature and humidity and the measured outdoor temperature and humidity reach a set humidity condition (hereinafter, referred to as a “set condition”), the first desiccant heat exchanger  41  provided in the first common passage  11 , through which indoor air and outdoor air flows, to absorb or desorb moisture in the air operates in a dry mode, and a second desiccant heat exchanger  42  provided in the second common passage  12  to absorb or desorb moisture in the air operates in the dry mode. 
     In this case, the drying operation step includes: a heat exchanger control step in which refrigerant is switched from the compressor to be supplied, so that one desiccant heat exchanger needed to be dried (a condenser-type desiccant heat exchanger) out of the first desiccant heat exchanger  41  and the second desiccant heat exchanger  42  acts as a condenser while the other desiccant heat exchanger not needed to be dried (an evaporator-type desiccant heat exchanger) acts as an evaporator; and a flow rate control step which is performed simultaneously with the heat exchanger control step, and in which a flow rate of air passing through the condenser-type desiccant heat exchanger (the flow rate is hereinafter referred to as a “first flow rate”) is controlled to be less than a flow rate of air passing through the evaporator-type desiccant heat exchanger (the flow rate is hereinafter referred to as a “second flow rate”). 
     The heat exchanger control step may be defined as a step in which refrigerant discharged from the compressor  45  is supplied first to the condenser-type desiccant heat exchanger using the refrigerant switching valve  44 . 
     The first desiccant heat exchanger  41  and the second desiccant heat exchanger  42  are replaced by the term “condenser-type desiccant heat exchanger” or “evaporator-type desiccant heat exchanger”, but indoor dehumidification or humidification is not actually performed, and thus, it is desirable to define the first desiccant heat exchanger  41  and the second desiccant heat exchanger  42  by classifying the same according to a flow of refrigerant. 
     Meanwhile, the heat exchanger control step may be defined as a step in which, when the above-described set condition is satisfied, the first desiccant heat exchanger  41  and the second desiccant heat exchanger  42  are compared in terms of a percentage of moisture absorbed onto a surface (hereinafter, referred to as a “moisture absorption rate”) and then refrigerant discharged from the compressor  45  is supplied first to the condenser-type desiccant heat exchanger using the refrigerant switching valve  44 . 
     In addition, the heat exchanger control step may be a step in which a desiccant heat exchanger  41  or  42  having a high moisture absorption rate out of the first desiccant heat exchanger  41  and the second desiccant heat exchanger  42  is determined to be the condenser-type desiccant heat exchanger. 
     Meanwhile, the flow rate control step is a step in which the first flow rate and the second air flow rate are controlled by adjusting a rotation amount of a plurality of dampers  62  to  68  composed of a plurality of shutter plates (not indicated by reference numerals) which rotates horizontal axes relative to the plurality of chambers  52  to  58  provided to suction indoor air or outdoor air into the first common passage  11  and the second common passage  12  or discharge the indoor air or outdoor air to the first common passage  11  and the second common passage  12 . 
     More specifically, the flow rate control step may be a step in which, out of the plurality of dampers  62  to  68 , the indoor suction damper  62  and the indoor discharge damper  64  are closed and the outdoor suction damper  66  and the outdoor discharge damper  68  are opened. 
     Unlike in the general ventilation, dehumidification, and humidification modes, the preferred embodiment of the control method of a ventilation apparatus according to the present invention focuses on a drying operation which is performed such that outdoor air is suctioned into an inner space through the outdoor suction damper  66  in the first common passage  11  and the outdoor suction damper  66  in the second common passage  12 , at the same time, and, while passing through the first desiccant heat exchanger  41  and the second desiccant heat exchanger  42  respectively provided in the first common passage  11  and the second common passage  12 , the suctioned outdoor air dries the first common passage  11  and the second common passage  12 . 
     However, since the second desiccant heat exchanger  42  acting as an evaporator-type desiccant heat exchanger absorbs moisture, the same may not be dried properly, and, for this reason, in the preferred embodiment of the control method of a ventilation apparatus according to the present invention, temperature in the entire system including the first common passage  11  and the second common passage  12  is controlled to increase so that the evaporator-type desiccant heat exchanger is dried easily. 
     That is, in the preferred embodiment of the control method of a ventilation apparatus according to the present invention, for example, when it is assumed that the condenser-type desiccant heat exchanger is provided in the first common passage  11  and the evaporator-type desiccant heat exchanger is provided in the second common passage  12 , the outdoor suction damper  66  and the outdoor discharge damper  68  in the second common passage  12  are controlled to be fully opened while the outdoor suction damper  66  and the outdoor discharge damper  68  in the first common passage  11  are controlled to be opened to an extent where the first flow rate is less than the second flow rate. 
     As above, the first flow rate of air suctioned into the first common passage  11 , in which the condenser-type desiccant heat exchanger, and the second flow rate of air suctioned into the second common passage  12 , in which the evaporator-type desiccant heat exchanger, are controlled by properly adjusting a degree of opening of the above-described dampers  62  to  68 , and, by doing so, temperature of the entire system increases, which makes moisture quickly desorbed from the evaporator-type desiccant heat exchanger and the condenser-type desiccant heat exchanger at the same time. 
     As such, if the dry mode operation time is reduced, it is possible to minimize a disruption time of an indoor dehumidification mode, thereby greatly improving dehumidifying performance. 
     As above, the preferred embodiment of the control method of a ventilation apparatus according to the present invention has been described in detail with reference to the accompanying drawings. However, embodiments of the present invention is not necessarily limited to the above-described embodiment, and it is apparent to one of ordinary skill in the art that various changes may be made thereto without departing from the claims and equivalents thereof. Thus, the scope of the present invention should be defined by the appended claims.