Air Supply Structure and Displacement Air Conditioning System

This is a continuation of International Application No. PCT/JP2024/006671 filed on Feb. 22, 2024, which claims priority under 35 U.S.C. § 119 (a) to Patent Application No. 2023-026713, filed in Japan on Feb. 22, 2023, all of which are hereby expressly by reference into the present application.

The present disclosure relates to an air supply structure and a displacement air conditioning system.

In a room, air warmed by a heat generating object such as an electrical appliance or a human body rises upward. When warm air rises upward, foreign materials such as dust also rise upward along with the air. Furthermore, the breath (carbon dioxide) of an individual living in the room may contain disease-causing germs such as viruses. Since the living individual is a heat generating object, carbon dioxide rises upward, and disease-causing germs also rise upward together. In other words, an air layer in an upper region of the room is a mixed air layer in which warm air and pollutants are mixed.

Meanwhile, indoor air conditioning methods, such as a displacement air conditioning system, and a stratification air conditioning system, are widely known. These air conditioning systems exhaust the air in an upper region of the room to the outside of the room, and perform air conditioning processes such as temperature adjustment, dehumidification, and a cleaning process on the air, and supply the air into the room.

Japanese patent No. 5872081 discloses an air conditioning system that blows air for cooling linearly downward through a blow-out port provided on a ceiling side, and raises heated air linearly from a heat generating object such as a machine tool without colliding with the air for cooling blown downward.

For indoor air conditioning using the above-mentioned indoor air conditioning method, a supply method has been widely used, in which when air-conditioned air after air conditioning is supplied into a room, the air-conditioned air is blown out from an upper side of the room to the floor. However, as mentioned above, a mixed air layer is present in an upper region of the room, and thus when air-conditioned air falls from the upper region of the room to the floor, the air in the mixed air layer including pollutants is caught in the air-conditioned air.

This can be coped with to some extent by reducing the wind speed of the air-conditioned air blown out from an upper region of the room. However, as the wind speed of the air-conditioned air decreases, the time during which the air-conditioned air passes through the mixed air layer increases, and thus when the temperature difference between the air in the mixed air layer and the air-conditioned air is large, a problem arises in that the air-conditioned air is more likely to be affected by the temperature of the mixed air layer. However, the air conditioning system of Japanese patent No. 5872081 does not consider such a problem, and thus cannot solve the problem.

The present disclosure has been made in view of the above circumstances, and it is an object of the disclosure to provide an air supply structure and a displacement air conditioning system including the air supply structure that, when the air that has undergone air conditioning is supplied from an upper region of a room, can cause the air to descend quickly while preventing or reducing pollutants being caught in the air.

An air supply structure according to a first aspect of the present disclosure is provided above a room that is a target of a displacement air conditioning system and in which a thermal stratification or a pollutant concentration stratification is formed. The air supply structure introduces air into the room. The air supply structure includes an air passage that opens toward a lower portion of a target space, and blows out air. The air passage includes an inner portion on a center side from which air is blown out at a first average wind speed, and an outer portion from which air is blown out at a second average wind speed lower than the first average wind speed. The outer portion is provided on an outer side of the inner portion.

In an air supply structure according to a second aspect of the present disclosure, the inner portion is defined by an inner air passage pipe on a center side of the air passage pipe portion, and the outer portion is defined by the inner air passage pipe and an outer air passage pipe adjacent to the inner air passage pipe.

In an air supply structure according to a third aspect of the present disclosure, the inner air passage pipe has a dimension smaller than the outer air passage pipe in a blowing direction, or the inner air passage pipe has a larger dimension than the outer air passage pipe in a direction intersecting the blowing direction.

In an air supply structure according to a fourth aspect of the present disclosure, a distance between the outer air passage pipe and the inner air passage pipe is smaller than a diameter of the inner air passage pipe.

An air supply structure according to a fifth aspect of the present disclosure further includes a housing including a through hole configured to introduce air, and a guide configured to guide the air flowing in through the through hole to the air passage pipe portion.

In an air supply structure according to a sixth aspect of the present disclosure, the guide includes at least one curved plate.

In an air supply structure according to a seventh aspect of the present disclosure, the through hole is disposed in a side portion of the housing, the air passage is disposed in a lower portion of the housing, and the guide is disposed at a vertical and horizontal position corresponding to the through hole and at a horizontal position corresponding to the air passage.

In an air supply structure according to an eighth aspect of the present disclosure, the guide is disposed at a position overlapping an axis of the air passage.

A displacement air conditioning system according to a ninth aspect of the present disclosure includes the air supply structure described above.

In the following, an indoor unit (air supply structure) of a displacement air conditioning system according to an embodiment of the present disclosure will be described in detail based on the drawings. In the displacement air conditioning system, outdoor air that is fresh air introduced from the outside of the room, and the indoor air containing pollutants sucked inside the room are transported to an air conditioner. The outdoor and indoor air transported to the air conditioner is cleaned and cooled or heated to a predetermined temperature, is supplied to the indoor unit through a duct as air-conditioned air, and then blown into the room by an air supply mechanism. The indoor unit blows out the air-conditioned air so that one-way air flow is formed, and the air directly reaches the floor surface. Also, warm indoor air heated by an individual's body as a heat generating object naturally rises in an ascending air current. The indoor air contains pollutants, and such part of the indoor air is sucked and transported to the air conditioner. In this manner, a thermal stratification and a concentration stratification are formed in a room to which the displacement air conditioning system is applied. Specifically, a lower portion of the room is filled with clean air with a low temperature, and in an upper portion of the room, a layer of air containing pollutants with a high temperature is formed.

is a schematic view illustrating a state in which an indoor unit(air supply structure) according to Embodiment 1 is disposed on a ceilingof a room R,is a perspective view, as seen from diagonally below, of the indoor unitinstalled in the room R, andis a vertical sectional view schematically illustrating the configuration of the indoor unitaccording to Embodiment 1. The arrows inindicate a flow of air, and the dashed line inindicates the part of the indoor unitprovided on the back side of the ceilingand not seen. The figure within the circle inis an enlarged view of the portion surrounded by the dashed-line circle.

The indoor unitis connected to a duct, and provided above the room R. Specifically, the indoor unitis provided on the ceiling of a displacement air conditioning system that forms a thermal stratification in the room R as the target space, and introduces air into the room R. The indoor unitmay be disposed on the ceilingof the room R, or may be a so-called skeleton or suspended from roof. In the following, for the purpose of illustration, an example will be described in which the indoor unitis disposed on the ceiling.

The indoor unitblows out air (hereinafter referred to as supply air) supplied through the ductto the floor from an upper region of the room R. Here, the supply air includes, for example, the air obtained by performing a process such as heating, cooling, dehumidification, or humidification on the outdoor air or mixed air between the outdoor air and the air in the room R.

The indoor unitincludes a housingthat receives the supply air through the ductand temporarily stores the supply air, and an opening(blow-out tube) that blows out the supply air in the housinginto the room R.

The housingis made of, e.g., metal, and has a hexahedron shape extending in a horizontal direction. In one of four lateral walls of the housing, a lateral wall through hole(through hole) is formed (see), which has a size corresponding to the size of the vertical section of the duct. One end of the ductis connected to the lateral wall through hole. In other words, the housingcommunicates with the duct.

In a central portion of the lower wall of the housing, a circular lower wall through holeis formed, which has a size corresponding to the cross-sectional size of the opening. The upper end of the openingis connected to the lower wall through hole. In other words, the housingcommunicates with the opening. For example, the housingand the openingare integrally formed.

In the housing, the lateral wall through holeconnected to the ductis formed in one lateral wall, and the lower wall through holeconnected to the openingis provided in the lower wall, thus the penetration direction (the arrow direction in) of the lateral wall through holeand the penetration direction (the white arrow direction in) of the lower wall through holeintersect each other, and are approximately perpendicular. In other words, the axial direction of the ductintersects the axial direction of the opening.

As with the housing, the openingis made of, e.g., metal, and has a cylindrical shape extending in a vertical direction. The openingis disposed (see) at a central portion of the ceiling, in other words, at a position opposed to a central portion of the floor. As described above, in the opening, an upper end portis connected to the housing, and a lower end portopens toward the floor.

The size of the lower end portis larger than the size of the lateral wall through hole. For example, the size of the lower end portis 2 to 7 times larger than the size of the lateral wall through hole. As in, only the lower end portof the openingis exposed from the ceiling, and other portions of the indoor unitare provided on the back side of the ceilingand not seen. When air flows into the housingthrough the duct, the air causes friction with the inner peripheral surface of the duct. Due to frictional resistance caused by such friction, the air passing through the lateral wall through holeof the housinghas a wind speed distribution in which the wind speed is faster on a center side of the ductthan in the vicinity of the inner peripheral surface of the duct. Meanwhile, in the indoor unitaccording to Embodiment 1, the size of the lower end portis larger than the size of the lateral wall through hole, and thus the air with the aforementioned wind speed distribution maintained flows through the lower end port, that is, the opening.

The inside of the openingis provided with an air passage pipe portion (air passage)through which the supply air from the housingpasses. The air passage pipe portion (air passage)is provided at an upper portion (upstream side) of the openingand apart from the lower end port. The air passage pipe portionhas a plurality of air passage pipesin a hexagonal tube shape extending in a vertical direction (see the enlarged view in) that form the air passage pipe portion (air passage). In the air passage pipe portion, the plurality of air passage pipesare adjacently disposed in a honeycomb pattern. Specifically, the plurality of air passage pipeshave the same dimension, and are adjacently disposed horizontally in the same plane (see). The supply air from the housingpasses through the air passage pipes, and blows out through the lower end portinto the room R.

In each air passage pipe, let h be the vertical dimension and letbe the horizontal dimension (see), then the aspect ratio (h/) of the vertical dimension to the horizontal dimension is greater than or equal to 1. The horizontal dimensionvaries with the shape of the air passage pipe. When the air passage pipehas a hexagonal tube shape, the horizontal dimensionmay be the distance between the opposed walls, or may be the distance between vertices of the hexagon. When the air passage pipedoes not have a hexagonal tube shape, the horizontal dimensionis the greatest dimension in the horizontal direction.

The vertical dimension (h) of each air passage pipeis less than or equal to the vertical dimension of the opening. In other words, the vertical dimension (h) of each air passage pipemay be at most equal to the vertical dimension of the opening. In other words, depending on the opening, the vertical dimension (h) of each air passage pipeis determined, and the upper limit of the aspect ratio (h/) of each air passage pipeis also determined.

The upper end of each air passage pipeis disposed at the position lower than or equal to the center of the lateral wall through holein a vertical direction. Thus, it is possible to reduce the loss of wind pressure of the supply air that enters the housingthrough the lateral wall through hole, and flows into the opening. Thus, the air volume of the supply air (hereinafter referred to as the blow-out supply air) that blows out through the lower end portof the openingcan be maintained.

In the indoor unitaccording to Embodiment 1, the supply air from the housingpasses through the air passage pipe portionof the opening, and blows out through the lower end portinto the room R. When the supply air passes through the plurality of air passage pipesof the air passage pipe portion, the wind direction of the supply air is guided in the extension direction of the air passage pipes, that is, vertically downward from the lower end port.

As in, the air passage pipe portionis circular, and includes the plurality of air passage pipes. In the air passage pipe portion, a portion including a plurality of air passage pipes(inner air passage pipes) in a radially central portion is referred to as an inner portion, and a portion including a plurality of air passage pipes(outer air passage pipes) radially outward of the inner portion is referred to as an outer portion. In other words, the air passage pipe portionincludes the inner portion on a center side, from which air is blown out at a first average wind speed, and the outer portion outward of the inner portion, from which air is blown out at a second average wind speed lower than the first average wind speed. In other words, the inner portion is defined by the inner air passage pipeson the center side of the air passage pipe portion, and the outer portion is defined by the inner air passage pipesand the outer air passage pipesadjacent to the inner air passage pipes. For example, in Embodiment 1, in the air passage pipe portion, the outside with respect to a center C of a line segment (see) is referred to as the outer portion, and the inside with respect to the center C is referred to as the inner portion, the line segment being drawn horizontally from the centroid of the opening(the air passage pipe portion) to the end of the opening. Also, of the supply air blown out through the opening(the air passage pipe portion), the air from the outer portion of the air passage pipe portionis referred to as the outer portion of the supply air, and the air from the inner portion of the air passage pipe portionis referred to as the inner portion of the supply air.

In the room R, air warmed by a heat generating object such as an electrical appliance or a human body rises upward. When warm air rises, foreign materials such as dust also rise together. Furthermore, the breath (carbon dioxide) of an individual living in the room R may contain disease-causing germs such as viruses, and since the living individual is a heat generating object, disease-causing germs also rise along with rise of carbon dioxide. In other words, an air layer in an upper region of the room is a mixed air layer in which warm air and pollutants are mixed.

When the blow-out supply air is blown out through the lower end port, and falls from the ceilingof the room R to the floor, a mixed air layer is present as described above, thus a problem arises in that the air in the mixed air layer containing pollutants is caught in the blow-out supply air.

Such a problem can be addressed to a certain extent by reducing the wind speed of the blow-out supply air blown out through the lower end port, but as the wind speed of the blow-out supply air decreases, the time during which the blow-out supply air passes through the mixed air layer increases. Therefore, when the temperature difference is large between the air in the mixed air layer and the blow-out supply air, the blow-out supply air is more likely to be affected by the temperature of the mixed air layer.

In contrast, in the indoor unitaccording to Embodiment 1 having the above-described configuration, the problem can be addressed by blowing out the blow-out supply air with different wind speeds in the outer portion and the inner portion. In the indoor unitaccording to Embodiment 1, the blow-out supply air blown out through the lower end portof the openinghas the average wind speed in the outer portion of the air passage pipe portionlower than or equal to the average wind speed in the inner portion of the air passage pipe portion. For example, in the blow-out supply air, the average wind speed (the second average wind speed) in the outer portion is 0.2 m/s to 1 m/s, and the average wind speed (the first average wind speed) in the inner portion is higher than or equal to 1 m/s. Here, the average wind speed is the numerical value obtained by dividing the measurement results at N points by N.

In this way, the average wind speed in the outer portion of the blow-out supply air is lower than or equal to 1 m/s and slow, and thus, during the time since the air is blown out through the lower end portuntil the air falls to the floor of the room R, when passing through the mixed air layer, pollutants being caught in the blow-out supply air are prevented or reduced.

Since the average wind speed in the inner portion of the blow-out supply air is higher than or equal to 1 m/s, the time during which the blow-out supply air passes through the mixed air layer can be reduced, thus it is possible to reduce the effect of the mixed air layer on the temperature of the blow-out supply air as much as possible.

is a view illustrating a simulation result of measurement of the wind speed of the blow-out supply air through the lower end portin the indoor unitaccording to Embodiment 1.shows the wind speed by light and shade, and a lighter area indicates a faster wind speed.

As seen from, the blow-out supply air blown out through the lower end portof the indoor unithas distinct light and shade contrast at the boundary (see the arrow in) between the air layer in the inner portion of the air passage pipe portionand the air layer in the outer portion of the air passage pipe portion, and the air layer in the outer portion and the air layer in the inner portion have different wind speeds. It can be identified that the air layer in the inner portion is brighter and higher in wind speed than the air layer in the outer portion. In, the wind speed in the air layer in the inner portion is 1.3 m/s, and the wind speed in the air layer in the outer portion is 0.7 m/s.

In the indoor unitaccording to Embodiment 1, as described above, the size of the lower end portis sufficiently larger than the size of the lateral wall through hole. Thus, it is possible to prevent or reduce an excessively high initial speed of the blow-out supply air blown out vertically downward from the lower end port.

In the indoor unitaccording to Embodiment 1, as described above, the ductis connected to one lateral wall of the housing, and the openingis connected to the lower wall of the housing. Thus, the indoor unitcan also be installed in the loft of the ceilingwith a height restriction.

In Embodiment 1, an example has been described in which the openinghas the air passage pipe portionincluding the plurality of air passage pipesextending in a vertical direction, and the plurality of air passage pipesare adjacently disposed horizontally in a honeycomb pattern in the same plane; however, the present disclosure is not limited to this.is a perspective view illustrating an openingof an indoor unitaccording to Embodiment 2. For the purpose of illustration,illustrates only the opening. The indoor unitaccording to Embodiment 2 also includes a plurality of air passage pipes, and the dimensions of the plurality of air passage pipesin a direction intersecting the blow-out direction of the blow-out supply air are different in the outer portion and the inner portion. In the following, an example will be described.

The openinghas a cylindrical shape, and the inside of the openingis provided with the air passage pipe portionthrough which the supply air from the housingpasses. The air passage pipe portionhas the plurality of cylindrical air passage pipesextending in a vertical direction. For example, the inner portion of the air passage pipe portionis provided with one, or two or more inner air passage pipes, and the outer portion of the air passage pipe portionis provided with one, or two or more outer air passage pipes. In the indoor unitaccording to Embodiment 2, the air passage pipeshave the same vertical dimensions and different diameters, and are disposed on the same axis. In other words, the plurality of air passage pipesare adjacently disposed in a multi-cylindrical shape. The diameter of each inner air passage pipeis greater than the distance between radially adjacent inner air passage pipeand outer air passage pipe. The plurality of air passage pipesare disposed with their lower ends aligned with the lower end portof the opening. When the supply air from the housingpasses between the air passage pipes, or between the lateral wall of the openingand the air passage pipes, the wind direction is guided vertically downward, and the supply air is blown out through the lower end portinto the room R. In the indoor unitaccording to Embodiment 2, as described above, the diameter of each inner air passage pipeis greater than the distance between radially adjacent inner air passage pipeand outer air passage pipe, and thus the average wind speed of the air blown out from the inner portion of the air passage pipe portionis faster than the average wind speed of the air blown out from the outer portion of the air passage pipe portion.

The same components as in Embodiment 1 are labeled with the same symbol, and a detailed description will be omitted.

In Embodiment 1, an example has been described in which the air passage pipe portionhas the plurality of air passage pipesin a hexagonal tube shape extending in a vertical direction, and the plurality of air passage pipesare adjacently disposed horizontally in a honeycomb pattern in the same plane; however, the present disclosure is not limited to this.is a perspective view illustrating an openingof an indoor unitaccording to Embodiment 3. For the purpose of illustration,illustrates only the opening.

The openinghas a cylindrical shape, and the inside of the openingis provided with an air passage pipe portionthrough which the supply air from the housingpasses. The air passage pipe portionis provided at an upper portion (upstream side) of the opening, apart from a lower end port. The air passage pipe portionhas a plurality of rectangular tube air passage pipesextending in a vertical direction. In the air passage pipe portion, a plurality of air passage pipesare adjacently disposed in a lattice pattern. Specifically, the plurality of air passage pipeshave the same dimension, and are adjacently disposed horizontally in the same plane. When the supply air from the housingpasses through the air passage pipes, the wind direction is guided vertically downward, and the supply air is blown out through the lower end portinto the room R.

The same components as in Embodiment 1 are labeled with the same symbol, and a detailed description will be omitted.

is a vertical sectional view schematically illustrating the configuration of an indoor unitaccording to Embodiment 4. As in Embodiment 1, the indoor unitis connected to the duct, provided above the room R, and blows out the supply air supplied through the ductto the floor from an upper region of the room R. The indoor unitincludes a housingand an opening.