JP7580894B2 - Clean room air conditioning system - Google Patents

Description

The present invention relates to an air conditioning system for a clean room. In particular, it relates to a stratified air conditioning system that creates temperature stratification in a clean room.

Figure 15 shows an example of an air conditioning system in a clean room. The target space S is configured as a ballroom-style industrial clean room, and multiple air blowing units 2 are installed on the ceiling 1. The air blowing units 2 are devices called fan filter units (FFUs) with a fan on the upper side of the housing and a HEPA filter on the lower side. The fan draws air above the ceiling 1 into the housing and blows it onto the filter, and the air that has passed through the filter and been purified is sent out generally downward as indoor air A1 to the target space S below, forming a non-unidirectional indoor airflow that dilutes and mixes indoor dust with clean air, rather than a unidirectional pushing flow.

The floor 3 of the target space S is constructed as a raised floor made of materials such as punched panels and gratings. The air sent from the blower unit 2 to the target space S as indoor air A1 passes through the openings in the floor 3 and escapes as return air A2 into the space under the floor, then passes through the return shaft 4 that connects the space under the floor to the space above the ceiling, and is again supplied to the target space S as indoor air A1 from the blower unit 2.

In the target space S, which is an industrial clean room, equipment 5 such as production equipment is in operation, and the indoor air A1 receives exhaust heat from the equipment 5, becomes heated, and escapes under the floor as return air A2. The heated return air A2 must be cooled to a temperature suitable for the operation of the equipment 5 before returning from under the floor to the ceiling space and being sent out again by the blower unit 2. In the example shown here, a cooling unit 6, which is a dry coil, is provided near the entrance of the return shaft 4, and is configured to cool the return air A2 after it escapes through the floor 3 of the target space S.

Thus, in the air conditioning system shown in FIG. 15, clean air is supplied to the target space S from the blower unit 2 as a generally downward airflow, while circulating air throughout the entire facility including the target space S.

Note that the example shown here is a schematic diagram; in actual industrial clean rooms, in addition to the equipment shown in the diagram, additional equipment such as an outdoor air conditioner and a humidifier are usually installed, but these are not shown here.

Prior art documents related to this type of clean room air conditioning system include, for example, Patent Document 1 below.

JP 2008-128618 A

In the conventional clean rooms described above, a certain amount of partitioned space is required around the target space S for air circulation, maintenance, and the like. Above the ceiling 1 where the numerous blower units 2 are installed, a space above the ceiling is required to ensure air flow to the blower units 2 and to enable maintenance of the blower units 2, and below the floor 3 installed as a raised floor, a certain amount of underfloor space must be provided as an air flow path, as a utility space, or as a maintenance space. In addition, an area is required to install the return shaft 4 that sends the return air A2 from under the floor to the ceiling. As a result, the area that can be used as a clean room is limited, and the entire facility becomes larger.

In addition, in order to supply a non-unidirectional airflow that is broad and generally downwards to the target space S to dilute the dust generated indoors, it is necessary to construct a wide ceiling 1 as a cell ceiling and place the blower units 2 and blanking panels there, since the blower units 2 are installed on the ceiling at regular intervals, even if they are sparse. Furthermore, due to the operation of the blower units 2 and the static pressure of the fan blowing on the filter under the housing of the blower units 2, the pressure difference with the atmosphere created by the balancer damper to maintain a slight positive pressure in the room, and the pressure loss of the filter, negative pressure is generated at the fan intake of the blower units 2, that is, in the space above the ceiling, so a mechanism is required on the building structure side to prevent dust from entering here from the outside. In addition, since the space under the floor is also an air flow path, dust prevention measures are also required here to maintain the cleanliness of the air, and these are factors that increase the cost of constructing the target space S as a clean room.

In view of the above circumstances, the present invention aims to provide a clean room air conditioning system that can realize a clean room in an appropriate manner while saving space and at low cost.

The present invention provides a ceiling having a fan-filter unit equipped with a fan and a filter in a part of a target space,
A ceiling side wall is provided between the lower ceiling and the upper ceiling at a position corresponding to an edge of the lower ceiling in a plan view, and an internal space of the lower ceiling is divided by the lower ceiling and the ceiling side wall,
The air cooled by the cooling unit is sent downward toward the floor from the air blowing unit arranged in a line on the lower ceiling,
The blower unit and the wall of the target space are arranged so that at least a part of the main flow of air sent out from the blower unit flows downward along the wall of the target space and then further flows along the wall and floor of the target space;
The main flow of air sent from the blower unit toward the floor collides with the floor, flows along the surface of the floor due to the Coanda effect, and is guided in a desired direction perpendicular to the arrangement direction of the blower units,
A return air vent that communicates the interior space of the lowered ceiling with the space outside the lowered ceiling is located above the floor at a position corresponding to the intended direction of the air being guided in a plan view from the blower unit,
This relates to an air conditioning system for a clean room, characterized in that the air guided in the desired direction from the blower unit reaches a position beyond the return air port in a plan view, rises, and is taken into the return air port.

In the clean room air conditioning system of the present invention, the return air vent can be provided in the ceiling side wall.

The air conditioning system for the clean room of the present invention can be configured so that the air flow that is sent from the blower unit toward the floor and guided along the floor is guided in a desired direction by being blocked in the horizontal direction by an air flow sent from another blower unit or by a wall.

The air conditioning system for the clean room of the present invention can be configured so that the air flow is blown from the blower unit toward the floor and guided along the floor in a desired direction, and after reaching a position beyond the return air outlet, collides with an air flow blown from another blower unit or with a wall and rises.

The air conditioning system for the clean room of the present invention can be configured so that the upper ceiling is a vertical ceiling that is the floor slab or roof slab of the upper floor.

The clean room air conditioning system of the present invention can realize a clean room in a space-saving and inexpensive manner.

1 is a schematic elevational view showing an example (first embodiment) of a configuration of an air conditioning system for a clean room according to the present invention; FIG. 2 is a schematic plan view of the air conditioning system of FIG. 1 . FIG. 11 is a schematic elevational view showing another example (second embodiment) of a configuration of an air conditioning system for a clean room according to the present invention. FIG. 4 is a schematic plan view of the air conditioning system of FIG. 3 . FIG. 11 is a schematic elevational view showing yet another example (third embodiment) of the configuration of the air conditioning system for a clean room according to the present invention. FIG. 6 is a schematic plan view of the air conditioning system of FIG. 5 . FIG. 11 is a schematic elevational view showing yet another example (fourth embodiment) of the configuration of the air conditioning system for a clean room according to the present invention. FIG. 8 is a schematic plan view of the air conditioning system of FIG. 7. FIG. 1 shows the results of simulating the air condition in a clean room air conditioning system according to the present invention, where (A) shows the air temperature distributed in a cross section of the space along the position of the equipment, and (B) shows the air temperature distributed in a cross section of the space along the position between the equipment. FIG. 13 shows the results of simulating the air flow in an air conditioning system of a clean room according to the present invention, where (A) shows the air flow velocity distributed in a cross section of space along the position of the equipment, and (B) shows the air flow velocity distributed in a cross section of space along the position between the equipment. FIG. 1 shows the results of simulating the state of air in an air conditioning system for a clean room according to the present invention, where (A) shows the age of air distributed in a cross section of space along the position of the equipment, and (B) shows the age of air distributed in a cross section of space along the position between the equipment. FIG. 13 shows the results of simulating the air conditions in a clean room air conditioning system according to a reference example (control example) of the present invention, where (A) shows the air temperature distributed in a cross section of the space along the position of the equipment, and (B) shows the air temperature distributed in a cross section of the space along the position between the equipment. FIG. 13 shows the results of simulating the air flow in an air conditioning system for a clean room according to a reference example (control example) of the present invention, where (A) shows the air flow velocity distributed in a cross section of the space along the position of the equipment, and (B) shows the air flow velocity distributed in a cross section of the space along the position between the equipment. FIG. 1 shows the results of simulating the state of air in an air conditioning system for a clean room according to a reference example (control example) of the present invention, in which (A) shows the age of air distributed in a cross section of the space along the position of the equipment, and (B) shows the age of air distributed in a cross section of the space along the position between the equipment. FIG. 1 is a schematic elevational view showing an example of a conventional air conditioning system for a clean room.

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

Figures 1 and 2 show an example (first embodiment) of a clean room air conditioning system according to the present invention, and parts in the figures that are given the same reference numerals as those in Figure 15 represent the same items.

In the target space S, in a part of the area in plan view, a double ceiling structure is formed in which a ceiling 11 is suspended below a ceiling 10 that is installed along the structure of the building frame (such as the floor slab of the upper floor), and an appropriate number of blower units 2 are installed on the lower ceiling 11 (for convenience, the ceiling 11 on which the blower units 2 are arranged will be referred to as the "lower ceiling" and the ceiling 10 located above the lower ceiling 11 will be referred to as the "upper ceiling" as necessary). In the conventional example shown in FIG. 15, the entire ceiling of the target space S in plan view was configured as a double ceiling, but in this first embodiment, only a part of the ceiling is double, that is, it is a dropped ceiling.

The ventilation unit 2 installed in the lower ceiling 11 is a device known as a fan filter unit (FFU) or the like that is equipped with a fan and a HEPA filter in a housing. The fan draws air above the lower ceiling 11 into the housing and blows it onto the filter, and sends the purified air downward as indoor air A1 into the target space S below.

In this specification, expressions such as "downward" and "sideways" are used in relation to air flow, etc., but these do not refer only to directions that exactly match the vertical or horizontal directions, but rather to directions that can be generally considered to be "downward" or "sideways" in the normal sense, or in an air conditioning system such as this invention. Similarly, expressions such as "along the floor" do not only refer to a direction that exactly matches the plane of the floor, but rather to a degree that it is generally along the plane of the floor. Similarly, the expression "orthogonal" does not only mean that one direction and another direction form an exact right angle, but refers to an angle that can be practically expressed as "orthogonal."

In plan view, the target space S is divided into an area with the lower ceiling 11 and an area without the lower ceiling 11, but at the boundary between these areas, i.e., at the edge of the lower ceiling 11, a wall 14 is provided between the lower ceiling 11 and the upper ceiling 10, and this wall 14 and the lower ceiling 11 separate the space above the lower ceiling 11 (the interior space of the lower ceiling) from the rest of the area (hereinafter, the wall that separates the interior space of the lower ceiling is referred to as the "ceiling side wall" and is distinguished from the wall 7 of the entire room including the target space S). A return air vent 15 is provided in the ceiling side wall 14 so as to penetrate the ceiling side wall 14 in the thickness direction, and the interior space of the lower ceiling is connected to the space outside it through the return air vent 15. A cooling unit 6, which is a dry coil, is provided in the return air vent 15.

The floor 13 of the target space is not configured as a punching panel or grating, unlike the floor 3 in the conventional example shown in FIG. 15. The floor 13 in this first embodiment is a structure that is closed all over in principle, and the space under the floor is not assumed to be an air flow path, and the air flows only above the floor 13 as described later (although it is possible to provide holes for passing some members such as cables in a part of the floor as necessary, as long as they do not interfere with the flow of air). In addition, the floor 13 may be made a raised floor as necessary, and the space under the floor may be used as a power usage space, but it does not need to be high enough for air to flow as in the conventional example in FIG. 15 (FIG. 1 shows an example in which the floor 13 is slightly raised, assuming that the space under the floor is used as a power usage space). On the upper surface of the floor 13, equipment 5 such as a production device is placed and operates. The equipment 5 is a production device that processes objects such as wafers of base materials for forming semiconductor integrated circuits, substrates for flat panel displays, or containers that can store a plurality of such items.

The setting of the area to be configured as a double ceiling and the arrangement of the blower units 2 will be explained. In this first embodiment, as shown in FIG. 2, the lower ceiling 11 is provided in two elongated rows along the walls 7 at both ends of the room, which is approximately rectangular in plan view. The blower units 2 are provided in a total of two rows, one row each, linearly along the longitudinal direction of the lower ceiling 11. The wall 7 is located on one side of the width of the lower ceiling 11, which is provided elongated along the wall 7, and the ceiling side wall 14 is located on the opposite side, with the blower unit 2 located in the center. When viewed from the blower unit 2, the wall 7 is located on one side and the ceiling side wall 14 is located on the other side in the direction perpendicular to the direction in which the multiple blower units 2 are arranged in plan view, and the return air vent 15 and the cooling unit 6 are located on the ceiling side wall 14.

As shown in FIG. 1, clean air is sent from the blower unit 2 downward toward the floor 13 of the target space S as indoor air A1. The downward indoor air A1 collides with the floor 13 and changes direction along the surface of the floor 13, but in the case of this first embodiment, the wall 7 is located in one of the four horizontal directions for the indoor air A1 sent out from the blower unit 2, and in the other two directions, there is a downward flow of indoor air A1 sent out from another adjacent blower unit 2. Most of the indoor air A1 sent out downward from the blower unit 2 and changed direction along the floor 13 is blocked by these in three directions and guided in the remaining one direction, which is the desired direction (Note that, with regard to the indoor air A1 sent out from the blower units 2 located at both ends of the blower units 2 arranged in a line, the wall 7 is located in two directions and there is a flow of indoor air A1 sent out from the adjacent blower unit 2 in one direction, so as a result, it also flows in the remaining one direction). Here, the "target direction" refers to the direction of the area to which it is desired to supply indoor air A1 as viewed from the blower unit 2, and in the case of a clean room such as the first embodiment, the direction of the area in which the equipment 5 is located. In terms of the drawing, it is the right for the blower units 2 arranged in the left row in the drawing, and the left for the blower units 2 arranged in the right row. In addition, the return air vent 15 and cooling unit 6 are located nearby in the position that corresponds to the target direction as viewed from the blower unit 2 in a plan view.

The indoor air A1, which has been redirected in this way, moves toward the center of the target space S in which the equipment 5 is placed. At this time, the main stream of the indoor air A1 crawls along the upper surface of the floor 13 due to the Coanda effect, while receiving the exhaust heat from the equipment 5. As a result, some of the indoor air A1, whose temperature has risen, moves upward due to the density difference caused by the temperature difference, and a temperature stratification is formed on the floor 13 where the higher the position, the higher the temperature, and the lower the position, the lower the temperature.

In this first embodiment, the lower ceiling 11 and the blower units 2 are provided along the walls 7 on both sides of the room in a plan view, and the air movement described above occurs for each of these blower units 2 on both sides. The flow of the indoor air A1 along the floor 13 flows from a position along the walls 7 on both sides of the target space S to the opposite side of the walls 7 (the direction in which the ceiling side walls 14 are provided and the return air vents 15 are located when viewed from the blower units 2), so when viewed from the floor 13, a flow of the indoor air A1 is formed from both ends of the target space S toward the center.

The main streams of the indoor air A1 flowing along the floor 13 from both ends of the target space S collide with each other in the center, where they begin to rise. The position where the indoor air A1 begins to rise is the desired direction as seen from the blower unit 2 that sends out the indoor air A1, and is a position beyond the nearby return air vent 15 in a plan view in relation to the desired direction.

Above the floor 13, where the main flow of indoor air A1 has flowed, ceiling side walls 14 are located on both sides of the target space S, and return air vents 15 are provided here. In the internal space of the lowered ceiling partitioned by the ceiling side walls 14 and the lower ceiling 11, negative pressure is generated by the operation of the blower unit 2, so the indoor air A1 that has risen above the floor 13 is sucked into the internal space of the lowered ceiling as return air A2 from the return air vent 15. At this time, the return air A2 is cooled to an appropriate temperature by the cooling unit 6 provided in the return air vent 15. The return air A2 that has returned to the internal space of the lowered ceiling is supplied again to the target space S as indoor air A1 by the blower unit 2.

In this way, in the air conditioning system of the first embodiment, as shown in FIG. 1, the indoor air A1 sent downward from the blower unit 2 installed at the end of the target space S flows along the upper surface of the floor 13, and some of it receives the exhaust heat from the equipment 5 along the way before reaching the center, and rises in temperature, while the rest of the air collides with each other when it reaches the center, and then rises, merges with the part of the indoor air, is sucked in through the return air port 15, falls as return air A2, and returns to the internal space of the ceiling, and is sent downward again from the blower unit 2 as indoor air A1. This is how the air circulation is formed. The air flow that receives the exhaust heat from the equipment 5 along the way, is heated, and becomes less dense than the surrounding air, and rises. The air flow sent out later by the blower unit 2 flows while maintaining dynamic pressure due to the Coanda effect, but is drawn in by the rising air, generating thermal drive. This phenomenon is also used to create an air conditioning system with a long reach.

Note that the example shown here is a schematic diagram, and in actual industrial clean rooms, in addition to what is shown in the diagram, various other facilities such as outdoor air conditioners, humidifiers, and even rails and transport vehicles for transporting products are usually installed as necessary. However, such configurations that are not directly related to the gist of this invention have been omitted from the illustrations here.

The air conditioning system of the first embodiment shown in Fig. 1 and Fig. 2 is advantageous in terms of space utilization efficiency compared to the conventional example shown in Fig. 15. In the conventional example of Fig. 15, in order to widely supply downflow to the target space S, the blower units 2 are installed on the ceiling at regular intervals, even if they are sparse, so it is necessary to construct a wide-area ceiling 1 as a cell ceiling and place the blower units 2 and blanking panels there. In the first embodiment shown in Figs. 1 and 2, the area where the blower units 2 are installed is limited to both sides of the room, and only this area needs to be a double ceiling, and the lower ceiling 11 is not required in other areas. In the area where the lower ceiling 11 is not installed, the height up to the upper ceiling 10 can be used, so more space can be used as a clean room compared to the example of Fig. 15, and it is easier to place, for example, tall devices and equipment. Even in this first embodiment, a certain amount of height is necessary for the air flow path in the internal space of the lowered ceiling, and a certain amount of area must be secured in the lower ceiling 11 near the blower unit 2 for maintenance purposes, but compared to the conventional example shown in Figure 15, the area of the area where the space can be effectively used in the vertical direction can be significantly increased.

In addition, since it is not necessary to install a cell ceiling over the entire area above the target space S, and it is sufficient to install the lower ceiling 11 only in a limited area, the cost of installing the double ceiling is limited. The internal space of the lower ceiling where negative pressure occurs is also smaller than the example in Figure 15, so the area on the structure side where dustproofing measures are applied can be minimized.

In addition, in the conventional example of FIG. 15, a certain level of height was required to use the space under the floor as an air flow path, but in this first embodiment, air flows above the floor 13, so from the perspective of air circulation, the floor 13 does not need to be a raised floor, and even if it is a raised floor, it does not need to be very high. Regarding the floor, in this first embodiment, the height direction of the space is effectively utilized, and a large space that can be used as a clean room can be secured. In addition, since air is not circulated under the floor, measures to maintain high air cleanliness are not required. Furthermore, temperature stratification is formed in the target space S, and the heated indoor air A1 rises due to density differences and is sucked into the ceiling as return air A2, so a structure such as a return shaft to send return air from under the floor to the internal space of the ceiling is not required, and the area of the equipment can be used more effectively.

This first embodiment also has advantages in terms of air conditioning efficiency, since it utilizes temperature stratification to efficiently cool the heights close to the floor 13 of the target space S that require air conditioning. In the conventional example shown in FIG. 15, the indoor air A1 is supplied to the entire area of the target space S by downflow, so it was necessary to adjust the temperature of the entire area below the ceiling 1 where the blower unit 2 is installed to an appropriate level, but in the case of this first embodiment, the return air A2 is collected from the heat pool formed near the upper ceiling 10 above the floor 13 where the equipment 5 is located, and then cooled. Since high-temperature air is the target for cooling, the efficiency of heat exchange in the cooling unit 6 is high.

Furthermore, the indoor air A1 forms a temperature stratification, and the heated air that needs to be temperature-adjusted automatically rises to a certain height of the return air outlet 15 due to density differences. This movement drives part of the air circulation described above, so energy related to air transport can also be saved.

In addition, in this first embodiment, the Coanda effect is effectively utilized to allow the air supplied from the blower unit 2 to reach far away. The indoor air A1 supplied from the blower unit 2 to the target space S is first sent downward and collides with the floor 13. The blower units 2 are arranged in a line along the longitudinal direction of the wall 7 on the lower ceiling that is elongated along the wall 7, so that the indoor air A1 supplied from the multiple blower units 2 arranged in a line collides with the floor 13 with the sides of each other's airflow also flowing downward. The colliding indoor air A1 is changed in direction along the upper surface of the floor 13, so that the Coanda effect allows it to reach a long distance from the blower unit 2, and clean air can be efficiently delivered to devices other than the device 5 located directly below the blower unit 2. This can be fully achieved if the cleanliness level is around class 6, for example. The circulation of air in the target space S will be described in detail later.

Figures 3 and 4 show another example (second embodiment) of the arrangement of equipment in an air conditioning system according to the present invention. In the first embodiment shown in Figures 1 and 2, the lower ceiling 11 on which the blower unit 2 is arranged is provided along the opposing walls 7 of a room that is generally rectangular in plan view, and indoor air A1 is sent out from both ends of the room toward the center. In this second embodiment, however, the lower ceiling 11 is provided along the wall 7 that forms one side of the room, and the blower unit 2 arranged there sends out indoor air A1 toward the opposite wall 7 where the lower ceiling 11 and the blower unit 2 are not installed. On the side that sends out indoor air A1 as seen from the blower unit 2 in plan view, the ceiling side wall 14, the return air vent 15 provided there, and the cooling unit 6 are located.

When the lower ceiling 11 and the blower unit 2 are arranged in this way, the indoor air A1 sent downward from the blower unit 2 collides with the floor 13, and is blocked in three directions by the wall 7 located in one horizontal direction and the downward air flow in two directions (or the wall 7 located in two directions and the downward air flow in one direction), as in the case of the first embodiment shown in Figures 1 and 2, and is guided in the remaining direction, which is the desired direction (the direction in which the nearby ceiling side wall 14 and the return air vent 15 are located as seen from the blower unit 2, and the direction in which the opposite wall 7 is located). A part of the indoor air A1 sent along the floor in the desired direction receives exhaust heat from the equipment 5 located along the way, increases in temperature, and rises due to the density difference with the surroundings. As described above, this causes thermal driving. On the other hand, in the area near the lower ceiling 11 and the opposite wall 7 where the blower unit 2 is not arranged, the flow of the indoor air A1 sent out from the blower unit 2 side and moving along the floor 13 collides with the wall 7 and starts to rise. The rising indoor air A1 merges with a portion of the indoor air A1 that has been heated by the exhaust heat of the equipment 5, and then descends again through the return air vent 15 on the ceiling side wall 14 and is sucked into the interior space of the ceiling. In this way, as shown in Figure 3, an air circulation is formed that is roughly half the air flow in the first embodiment (see Figure 1), and the target space S, which is a clean room, is realized in the same way as in the first embodiment.

Figures 5 and 6 show yet another example (third embodiment) of equipment arrangement of an air conditioning system according to the present invention. In this third embodiment, as in the first embodiment, a total of two rows of lower ceilings 11 and blower units 2 are arranged along opposing walls 7 in a room that is generally rectangular in plan view, but in addition, a third row of lower ceilings 11 and blower units 2 is provided in the central area of the room. In Figure 6, equipment 5 is omitted to avoid cluttering the drawing (the same applies to Figure 8 of the fourth embodiment described later).

The lower ceiling 11 and the blower units 2 of this third row are arranged parallel to the lower ceiling 11 and the blower units 2 of the first and second rows located at both ends of the room. If the lower ceiling 11 and the blower units 2 on the left side in Figures 5 and 6 are the first row, and the lower ceiling 11 and the blower units 2 on the right side are the second row, then the third row is closer to the second row than the center in the direction perpendicular to the arrangement of the blower units 2 of the first and second rows. Ceiling side walls 14 are provided on both sides of the lower ceiling 11 of the third row in the width direction (both ends in the direction perpendicular to the longitudinal direction of the lower ceiling 11 of the third row where the blower units 2 are arranged), and the third row is partitioned from the rest of the space. One of the ceiling side walls 14 on both sides of the third row (the side facing the first row) is provided with a return air vent 15 and a cooling unit 6.

The indoor air A1 sent out from the blower unit 2 in the first row (left side) collides with the floor 13, and as in the first embodiment shown in Figures 1 and 2, three horizontal directions are blocked by the flow of indoor air A1 from the wall 7 and the adjacent blower unit 2, and it is guided in the remaining desired direction (to the right). Similarly, the indoor air A1 sent out from the blower unit 2 in the second row (right side) is also blocked in three horizontal directions by the flow of indoor air A1 from the wall 7 and the adjacent blower unit 2, and it is guided in the remaining desired direction (to the left).

The indoor air A1 sent out from the blower unit 2 in the third row (center) also collides with the floor 13 and changes direction. At that time, in one of the four horizontal directions seen from the flow of the indoor air A1, there is a flow of indoor air A1 sent out from the blower unit 2 in the second row and flowing to the left, and in two directions there is a downward flow of indoor air A1 sent out from the adjacent blower unit 2 in the same third row (with regard to the indoor air A1 sent out from the blower units 2 located at both ends of the third row, there is a flow of indoor air A1 flowing from the blower unit 2 in the second row in one direction, there is a downward flow of indoor air A1 sent out from the adjacent blower unit 2 in the third row in one direction, and there is a wall 7 in yet another direction). The flow of indoor air A1, which changes direction along the floor 13, is blocked by these and guided to the remaining one direction (leftward), which is the desired direction. This direction is also the direction in which the nearby return air vent 15 is located as seen from the blower unit 2 in the third row.

The flow of indoor air A1 sent out from the first row of blower units 2 and moving to the right along the top surface of the floor 13, and the flow of indoor air A1 sent out from the third row of blower units 2 and moving to the left along the top surface of the floor 13 collide with each other at a position halfway between the first and third rows and begin to rise. The rising air flow changes direction again above the floor 13 and flows toward the return air vents 15 of the first and third rows, and then falls from the return air vents 15 to be sucked into the interior space of the ceiling as return air A2.

When the flow of indoor air A1 sent out from the second row of blower units 2 and moving leftward along the upper surface of the floor 13 reaches the vicinity of the third row of blower units 2, there is a flow of indoor air A1 sent downward from the third row of blower units 2 ahead. At this point, the flow of indoor air A1 sent out from the second row of blower units 2 changes direction and begins to rise. The rising air flow changes direction again above the floor 13, flows toward the second row of return air vents 15, and descends from the return air vents 15 to be sucked into the interior space of the ceiling as return air A2.

In this way, for the indoor air A1 sent out from the first and third row of blower units 2, a circulation roughly similar to that of the first embodiment shown in Figures 1 and 2 is formed, and for the indoor air A1 sent out from the second row of blower units 2, a circulation roughly similar to that of the second embodiment shown in Figures 3 and 4 is formed. As a result, a target space S that is a clean room is realized, similar to the first and second embodiments described above.

Figures 7 and 8 show yet another example (fourth embodiment) of the equipment arrangement of an air conditioning system according to the present invention. In this fourth embodiment, like the third embodiment, the first to third rows of lower ceiling 11 and blower units 2 are arranged at both ends and in the center of a room that is generally rectangular in plan view, and a fourth row of lower ceiling 11 and blower units 2 is also arranged in the center of the room.

In this fourth embodiment, the lower ceiling 11 and blower units 2 of the third and fourth rows are arranged parallel to the lower ceiling 11 and blower units 2 of the first and second rows located at both ends of the room, and are located in the center of the lower ceiling 11 and blower units 2 of the first and second rows. The fourth row is located in an area adjacent to the right side of the third row. Although not shown, a hanging wall or the like may be provided between the third and fourth rows to more reliably guide the airflow. Also, although an example is shown here in which a partition is provided between the internal space of the dropped ceiling of the third row and the internal space of the dropped ceiling of the fourth row, in some cases this partition may not be provided.

A ceiling side wall 14 is provided on the edge of the first row (left side) when viewed from the lower ceiling 11 of the third row, and on the edge of the second row (right side) when viewed from the lower ceiling of the fourth row, separating them from the rest of the space. These ceiling side walls 14 are provided with a return air vent 15 and a cooling unit 6.

When the flow of the indoor air A1 sent downward from the third row of blower units 2 collides with the floor 13, two of the four horizontal directions are blocked by the flow of the indoor air A1 sent downward from the adjacent blower units 2 (with regard to the indoor air A1 sent from the blower units 2 located at both ends, one direction is blocked by the flow of the indoor air A1 sent from the adjacent blower unit 2, and the other direction is blocked by the wall 7). Furthermore, one direction is blocked by the flow of the indoor air A1 sent downward from the fourth row of blower units 2 adjacent to the right, and it is guided in the remaining one direction (left side), which is the desired direction. The indoor air A1 flowing to the left collides with the indoor air A1 sent from the first row of blower units 2 and flowing to the right, turns upward, changes direction again above the floor 13, and is sucked into the return air vent 15 on the ceiling side wall 14.

Similarly, when the flow of indoor air A1 sent downward from the fourth row of blower units 2 collides with the floor 13, two of the four horizontal directions are blocked by the flow of indoor air A1 sent downward from the adjacent blower units 2 (with regard to the indoor air A1 sent out from the blower units 2 located at both ends, one direction is blocked by the flow of indoor air A1 sent out from the adjacent blower units 2, and the other direction is blocked by the wall 7). Furthermore, one direction is blocked by the flow of indoor air A1 sent downward from the third row of blower units 2 adjacent to the left, and it is guided in the remaining one direction (right side), which is the desired direction. The indoor air A1 flowing to the right collides with the indoor air A1 sent out from the second row of blower units 2 and flowing leftward, turns upward, changes direction again above the floor 13, and is sucked into the return air vent 15 of the ceiling side wall 14.

The flow of indoor air A1 sent out from the first and second row blower units 2 is generally similar to that in the first and third embodiments described above, so a detailed explanation will be omitted.

In this way, a target space S that is a clean room is realized, similar to the first to third embodiments described above.

The air circulation in each of the above embodiments is achieved by skillfully arranging another air flow or a wall 7 to guide the flow of indoor air A1 sent out from the blower unit 2. Specifically, first, the blower units 2 that send out the indoor air A1 downward are arranged in a line, so that the main direction of the indoor air A1 that is blown against the floor 13 and changed is limited to two directions perpendicular to the direction in which the blower units 2 are arranged. By placing the downward air flows adjacent to each other, the subsequent flow directions are mutually restricted. Furthermore, by further blocking one of the two directions with a wall 7 or another air flow (a downward, sideways, or upward air flow sent out from another blower unit 2), the direction of the indoor air A1 is guided in the desired direction.

The indoor air A1 thus sent out reaches a certain distance along the upper surface of the floor 13, where it collides with the wall 7 or another air flow (a downward, sideways, or upward air flow sent out from another blower unit 2) and rises, and is sucked into the return air port 15 provided above the floor 13. By appropriately arranging the wall 7 and air flow at the position where the indoor air A1 reaches, the flow of the indoor air A1 is well guided even at the destination where it reaches, and is suitably taken in as return air A2 from the return air port 15, thereby forming the air circulation as shown in Figures 1, 3, 5, and 7. The main feature of the present invention is that the indoor air A1 is sent out downward from the blower unit 2 to collide with the floor 13, and the flow of the indoor air A1 reaches a long distance by utilizing the Coanda effect, but in this case, if the downward flow of the indoor air A1 is simply made to collide with the floor 13, the flow will dissipate in all directions along the floor 13. Therefore, by devising the arrangement of the blower unit 2, wall 7, and return air vent 15, the flow of the indoor air A1 is induced, forming the circulation described above. Although the main purpose is to make the indoor air A1 reach far by utilizing the Coanda effect, a portion of the indoor air A1 that crawls along the floor receives the exhaust heat from the equipment 5, becomes warmer, becomes less dense than the surrounding air, and rises, generating a "thermal driving effect" that attracts the airflow that arrives later, creating a circulation flow that also forms temperature stratification with a long reach, while also working to make a certain amount of the indoor air A1 reach far.

Here, the return air vents 15 located near each blower unit 2 are located in the direction in which the indoor air A1 is sent out when viewed from the blower unit 2 in a plan view, so the indoor air A1 sent out from the blower unit 2 changes direction and reaches above the floor 13, and is then smoothly taken in as return air A2 from the return air vents 15. This positional relationship between the blower unit 2 and the return air vents 15 also acts as a factor in successfully creating the above-mentioned air circulation. If the return air vents 15 are provided on the ceiling side wall 14, the return air vents 15 can be easily provided in a position suitable for air circulation. This is because the ceiling side wall 14 that divides the internal space of the lowered ceiling is usually located in the desired direction when viewed from the blower unit 2 in a plan view, is located near the blower unit 2, and is located above the floor 13 and the blower unit 2.

In this way, by skillfully arranging the blower units 2, return air vents 15, walls 7, etc., it is possible to easily guide the flow of indoor air A1 in the desired direction, or to raise it and take it into the return air vent 15. Furthermore, even in a large clean room, by appropriately combining these, clean air at the appropriate temperature can be supplied to every corner of the target space. In this case, for example, five or more rows of lower ceilings 11 and blower units 2 may be provided. In addition to the air flow and walls 7, it is also possible to provide other objects or structures (such as partition-like objects) to guide the flow of indoor air A1, or to cause it to rise by colliding with them.

Figures 9 to 11 show the results of a simulation (simulation of an embodiment) of the air flow and conditions in a clean room designed based on the above-mentioned technical concept, with Figure 9 showing the distribution of air temperature, Figure 10 showing the air flow velocity, and Figure 11 showing the distribution of air age. In addition, (A) in each figure shows a cross section of the space where the equipment is arranged, and (B) shows a cross section of the space at a position between the equipment arrangements.

In the example shown here, it is assumed that eight pieces of equipment 5 are arranged in the left-right direction within the target space S, which is a clean room. Note that multiple pieces of equipment 5 are also arranged in the depth direction (the direction perpendicular to the paper surface), but this is not shown in the figure.

Above the left and right ends of the target space S, an internal space of a lowered ceiling is partitioned by the lower ceiling 11 and the ceiling side walls 14, and air is sent downward from the air blower unit 2 arranged on the lower ceiling 11, collides with the floor 13 and proceeds toward the center of the target space S. A return air vent 15 is provided on each of the left and right ceiling side walls 14 located above the floor 13, and the air that collides in the center of the target space S rises above the floor 13 before being taken in by the left and right return air vents 15.

On the other hand, Figures 12 to 14 show the results of a simulation (simulation of a reference example (control example)) of the air flow and conditions in a clean room assumed as a reference example (control example) of the present invention. Figure 12 shows the distribution of air temperature, Figure 13 shows the air flow velocity, and Figure 14 shows the distribution of air age. In addition, (A) in each figure shows a cross section of the space where the equipment is arranged, and (B) shows a cross section of the space at a position between the equipment arrangements (a position where no equipment is present).

As in Figures 9 to 11, eight pieces of equipment 5 are arranged in the left-right direction within the target space S, which is a clean room, and multiple pieces of equipment 5 are also arranged in the depth direction (the equipment 5 arranged in the depth direction is not shown).

In this reference example, there is no internal space of the lowered ceiling divided by the lower ceiling and the ceiling side walls, and air is sent out sideways from the blower units 2 on the left and right walls 7 toward the center of the target space S. In other words, the air conditioning system does not use the Coanda effect or temperature stratification, but instead sends out air sideways from the blower units 2 to a certain height (a height corresponding to the space where clean air at the right temperature is desired), and the air flow reaches directly to the center of the target space S. Above the blower units 2 on the wall 7, a return air vent 15 is provided at a height near the ceiling. The air sent out from the left and right blower units 2 collides with each other in the center of the target space S, starts to rise, changes direction again above the floor 13, and is taken in from the left and right return air vents 15.

9 and 12, the higher the air temperature, the whiter the area, and the lower the air temperature, the blacker the area. First, referring to FIG. 9B, which shows a simulation of the embodiment, it can be seen that the air flows well in the cross section where the equipment 5 does not exist, and the darker (lower temperature) air reaches the center of the target space S. Lighter (higher temperature) air forms a heat pool above the target space S, and this is taken in as return air from the return air port 15. Also, referring to FIG. 9A, it can be seen that even if the equipment 5 is arranged in the direction of air flow, the air slips through between them, and the darker (lower temperature) air reaches the center of the target space S. The darker (lower temperature) air is also distributed between the equipment 5, and it can be seen that the air flows around between the equipment 5 and the low temperature air is supplied. Also, in (A), it can be seen that the darker area in the center of the target space S reaches the vicinity of the upper ceiling 10, and the low temperature air collides with each other in the center and rises as a result.

Next, referring to Figure 12 showing a reference example, in (B), it can be seen that darker colored (lower temperature) air is distributed up to the center, similar to (B) of Figure 9, and in (A), it can be seen that darker colored (lower temperature) air is also distributed between the equipment 5, similar to (A) of Figure 9. In other words, in the reference example, similar to the embodiment, good conditions can be maintained in terms of air temperature throughout the entire target space S, even between the equipment 5. However, in the case of the reference example, in order to maintain good temperature conditions in the target space S in this way, it is necessary to increase the supply air volume compared to the embodiment, as will be described below.

Figures 10 and 13, which show the air flow speed, are compared. The arrows in Figures 10 and 13 indicate the vector of the air flow speed, with the direction of the arrow indicating the direction of the flow and the length of the arrow indicating the speed of the flow. First, referring to Figure 10(B), which shows a simulation of the embodiment, it can be seen that in the cross section where no device 5 exists, the air flow speed is generally fast, and a circulation similar to that shown in Figure 1 is formed. Next, referring to Figure 10(A), it can be seen that the air does not circulate as smoothly between devices 5 as in the cross section in (B), because the air is blocked by the devices 5. Nevertheless, it can be seen that arrows of a certain length exist between the devices 5, and that the air flow is maintained.

In contrast, in the reference example, referring to FIG. 13(B), it can be seen that the air flow slows down considerably near the center even in the cross section without the device 5. Furthermore, looking at (A), there are also areas between the devices 5 where the flow speed is close to zero.

This is thought to be because, when air is sent out sideways from the blower unit 2 placed on the wall 7 as in the reference example, a significant proportion of the air is sucked directly into the return air vent 15 located above it (short circuit), reducing the air flow toward the center of the target space S. On both the left and right sides of (A) and (B) of Figure 13, arrows indicating the air flow from the blower unit 2 to the return air vent 15 above it are displayed large. This requires a large air volume to be set in order to get the air to the center of the target space S, which increases the energy required for blowing the air (in fact, when referring to the arrow near the blower unit 2, the length of the arrow in the reference example (Figure 13) is longer than that in the embodiment (Figure 10), i.e., the air volume is larger. In the reference example, by increasing the supply air volume in this way, it is finally possible to cool the entire target space S to an appropriate temperature, as shown in Figure 12). In addition, the proportion of air taken in from the heat pool among the air to be cooled is relatively small, and the low-temperature air that has just been blown out from the blower unit 2 is also taken in and cooled, so the efficiency of cooling the air is also reduced. As in the embodiment shown in Figures 9 and 10, by blowing air downward from the blower unit 2 and using the Coanda effect and temperature stratification to supply the air flow, it is possible to make the air reach a long distance with a smaller amount of air, and by efficiently taking in air from the heat pool, the cooling efficiency can also be increased.

Next, Fig. 11 and Fig. 14 are compared. In Fig. 11 and Fig. 14, the air sent out from the blower unit 2 is displayed in areas with higher air age in white and areas with lower air age in black. When comparing (A) with (B), Fig. 11 is generally lighter in color than Fig. 14, and it can be seen that in the embodiment, the air age is kept low throughout the target space S (i.e., the air is circulated efficiently). In the reference example, referring particularly to Fig. 14 (B), it can be seen that there are dark areas at the height of the ceiling on the left and right sides of the target space S, where air with a high air age is stagnating. In addition, in both Fig. 14 (A) and (B), it can be seen that the light-colored (low air age) areas near the blower unit 2 extend to the vicinity of the return air port 15, and it can be seen that the low-air age air just sent out from the blower unit 2 is taken directly into the return air port 15. In contrast, in FIG. 11B, the relatively dark (high air age) area faces the return air inlet 15, and in the embodiment, it can be seen that air with a high air age is preferentially taken into the return air inlet 15. In FIG. 11A, the flow of air sent out from the blower unit 2 is blocked by nearby equipment 5, and as a result, the light-colored (low air age) area near the blower unit 2 extends to the position of the return air inlet 15. Even so, compared to FIG. 14A, the proportion of white (low air age) air taken in from the return air inlet 15 is small.

Thus, in the reference example, in order to maintain a good temperature condition as shown in FIG. 12, it is necessary to increase the supply air volume as shown in FIG. 13, but even if this is done, areas of relatively high air age remain in the target space S as shown in FIG. 14. In contrast, in the system of FIG. 9 to FIG. 11 to which the present invention is applied, the air is well circulated even with a relatively small supply air volume, and fresh air that has just been sent out from the blower unit 2 is always efficiently supplied to the entire target space S.

As described above, the air conditioning system for the clean room in each of the above-mentioned embodiments is configured such that a lower ceiling 11 in which the blower unit 2 is arranged is provided in a portion of the target space S, a ceiling side wall 14 is provided between the lower ceiling 11 and the upper ceiling 10 at a position corresponding to the edge of the lower ceiling 11 in a plan view, and the interior space of the lower ceiling is partitioned by the lower ceiling 11 and the ceiling side wall 14, air A1 is sent downward toward the floor 13 from the blower unit 2 arranged in a line on the lower ceiling 11, the flow of air A1 sent from the blower unit 2 toward the floor 13 is guided along the floor 13 in a desired direction perpendicular to the arrangement direction of the blower units 2, and a return air vent 15 that connects the interior space of the lower ceiling to the space outside it is located above the floor 13 at a position corresponding to the desired direction in which the air is guided in a plan view, as viewed from the blower unit 2, and the air A1 guided in the desired direction from the blower unit 2 reaches a position beyond the return air vent 15 in a plan view, rises, and is taken in by the return air vent 15. In this way, the Coanda effect and temperature stratification can be utilized to optimally supply air A1 sent out from the blower unit 2 into the target space S.

In addition, in each embodiment, the return air vent 15 is provided in the ceiling side wall 14. In this way, the return air vent 15 can be easily provided in a suitable position.

In addition, each embodiment is configured so that the flow of air A1, which is sent from the air blowing unit 2 towards the floor 13 and guided along the floor 13, is guided in a desired direction by being blocked in the horizontal direction by the flow of air A1 sent from another air blowing unit 2 or by the wall 7. In this way, the flow of air A1 can be appropriately guided in a desired direction with a simple configuration.

In addition, each embodiment is configured so that the air flow that is sent out from the blower unit 2 towards the floor 13 and guided along the floor 13 in the desired direction reaches a position beyond the return air port 15, collides with the air A1 flowing out from another blower unit 2 or with the wall 7, and rises. In this way, the air A1 flowing along the floor 13 can be raised with a simple configuration and suitably taken in by the return air port 15.

In addition, in each embodiment, the upper ceiling 10 may be a cell ceiling or panel ceiling like the lower ceiling 11, hiding the concrete pouring surface that generates dust, but the upper ceiling 10 may be coated with a dustproof paint to protect it from dust, and then the upper ceiling 10 may be made into a vertical ceiling under the floor slab of the upper floor or under the roof slab. Furthermore, if the building is made of steel, even if the underside of the floor is made of steel plate, such as a composite deck plate floor, dustproof measures such as gap treatment may be taken, and the steel plate on the underside of the floor may be used as the vertical ceiling 10 as it is. In this way, the installation cost of the upper ceiling 10, which is an interior material, can be reduced.

Therefore, according to each of the above embodiments, a clean room can be realized in an appropriate manner while saving space and at low cost.

The clean room air conditioning system of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the spirit of the present invention.

2 Blower unit 7 Wall 10 Ceiling (upper ceiling)
11 Ceiling (lower ceiling)
13 Floor 14 Ceiling side wall 15 Return air vent A1 Air (indoor air)

Claims (5)

A ceiling is provided in a portion of the target space, and a fan filter unit is provided as a ventilation unit.
A ceiling side wall is provided between the lower ceiling and the upper ceiling at a position corresponding to an edge of the lower ceiling in a plan view, and an internal space of the lower ceiling is divided by the lower ceiling and the ceiling side wall,
The air cooled by the cooling unit is sent downward toward the floor from the air blowing unit arranged in a line on the lower ceiling,
The blower unit and the wall of the target space are arranged so that at least a part of the main flow of air sent out from the blower unit flows downward along the wall of the target space and then further flows along the wall and floor of the target space;
The main flow of air sent from the blower unit toward the floor collides with the floor, flows along the surface of the floor due to the Coanda effect, and is guided in a desired direction perpendicular to the arrangement direction of the blower units,
A return air vent that communicates the interior space of the lowered ceiling with the space outside the lowered ceiling is located above the floor at a position corresponding to the intended direction of the air being guided in a plan view from the blower unit,
An air conditioning system for a clean room, characterized in that the air guided in the desired direction from the blower unit reaches a position beyond the return air port in a planar view, rises, and is taken in by the return air port. The air conditioning system for a clean room according to claim 1 , wherein the return air vent is provided in the ceiling side wall. 3. The air conditioning system for a clean room as described in claim 1 or 2, characterized in that the air flow sent out from the blower unit toward the floor and guided along the floor is guided in a desired direction by being blocked in a horizontal direction by an air flow sent out from another blower unit or by a wall. An air conditioning system for a clean room as described in any one of claims 1 to 3, characterized in that the air flow sent out from the blower unit toward the floor and guided along the floor in a desired direction is configured to rise after reaching a position beyond the return air outlet by colliding with an air flow sent out from another blower unit or a wall. 5. The air conditioning system for a clean room according to claim 1, wherein the upper ceiling is constituted by a vertical ceiling which is a floor slab or roof slab of an upper floor.

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