JP7580895B2 - Clean room air conditioning system - Google Patents

Description

The present invention relates to an air conditioning system for a clean room. Furthermore, it relates to an air conditioning system for an industrial clean room that is easily applicable to buildings with low floor heights.

Figure 11 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 fan filter units 2 are installed on the ceiling 1. The fan filter units 2 suck air above the ceiling 1 into a housing using a fan and blow it onto a filter covering the entire lower surface of the housing, and send the purified air that passes through the filter to the target space S below as indoor air A1.

The floor 3 of the target space S is constructed as a raised floor using materials such as punching panels and gratings. The air sent from the fan filter 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, is sent to the space above the ceiling through the return shaft 4 that connects the space under the floor with the ceiling, and is again supplied to the target space S as indoor air A1 from the fan filter unit 2.

In the target space S, which is an industrial clean room, equipment (device) 5 such as production equipment is in operation, and the indoor air A1 receives exhaust heat from the equipment 5 and is heated before being released 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 from the fan filter 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 to cool the return air A2 after it has passed through the floor 3 of the target space S.

In this way, in the air conditioning system shown in FIG. 11, clean air is supplied from the fan filter unit 2 to the target space S, while air is circulated throughout the entire facility including the target space S. In this type of air circulation, the fan filter unit 2 sends air generally downward into the target space S, but the fan filter units 2 are sparsely installed on the ceiling 1, and the airflow formed by this is not a unidirectional push-out flow, but a non-unidirectional airflow that dilutes and mixes dust generated in the room with the clean air.

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 with a fan in the circulation path are usually installed, but these are not shown here.

As an example of an old tunnel-type clean room related to this type of clean room air conditioning system, the following Patent Document 1 is an example of such a prior art document. Tunnel-type clean rooms have a higher level of cleanliness than ballroom-type clean rooms, but are similar in structure, so they are shown here as an example.

Japanese Unexamined Patent Publication No. 62-194140

In the conventional ballroom-type clean room described above, a return shaft space partitioned off from the target space S is required around the target space S for air circulation or to ensure an airway to the dry coil. Also, in order to blow down the air lifted by the return shaft with the fan of the fan filter unit 2, a space with a certain degree of planar area and height must be provided above the ceiling 1 (attic), on which the numerous fan filter units 2 are installed, to ensure airflow to the fan filter units 2 and to ensure space for a catwalk for maintenance of the fan filter units 2.

In addition, in order to sparsely install the fan filter units 2 as described above in the target space S and widely supply a non-unidirectional airflow, it is necessary to construct a large ceiling 1 as an installation surface for the fan filter units 2, which is a cell ceiling that is optimal for placing filters, in other words, a system ceiling. In the end, even if the fan filter units 2 are installed sparsely or in part of a panel ceiling, they are placed at regular intervals, which increases the equipment costs, so it is common to install cells over the entire surface and then cover it with blank panels.

Furthermore, in the case of an industrial clean room, a balancer damper (not shown) is installed in the passageway of the target space S or in the boundary partition between the room and the room, and a positive pressure is created by supplying air to the target space S with an outdoor air conditioner (not shown) so that the pressure is slightly positive relative to atmospheric pressure. Air circulated by the fan suction of the fan filter unit 2 flows from the target space S with this slight positive pressure, and negative pressure is generated in the ceiling space where the fan suction position is reached due to pressure loss in each part of the air passage, as the fan filter unit 2 operates. This creates a negative pressure difference between the space in the ceiling and the outside, which is at atmospheric pressure. For this reason, a pressure-resistant mechanism using costly sealing and sturdy panels is required on the building structure side to prevent dust from entering the space in the ceiling from the outside. In this way, the installation of a wide ceiling and a space in the ceiling was a factor in increasing the cost of constructing the target space S as a clean room.

In addition, there was a need for a solution to cases where it was difficult to install large-area cell ceilings or panel ceilings in the first place due to spatial constraints, such as low ceilings in the target buildings, which is where the effects of this project will be achieved.

In view of the above situation, the present invention aims to provide an air conditioning system for a clean room that reduces the area required for the installation surface of a fan filter unit, while allowing the remaining areas of the target space to be covered by a vertical ceiling, and can maintain a sufficient level of cleanliness in the target space.

The present invention provides a space for installing a device that needs to maintain its own temperature within a predetermined range while applying a thermal load to the surrounding air;
An adjustment unit provided above the floor, partitioned from a target space, and forming a space at a level above the device;
a fan filter unit provided on a lower surface of the adjustment unit and configured to blow air downward toward the floor;
a dry coil provided on a side surface of the adjustment unit, the dry coil regulating the temperature of air by circulating the air through the fan filter unit;
A suction port is provided on a side surface of the adjustment unit and communicates an internal space of the adjustment unit with a target space,
The adjustment section is configured as a box-shaped structure including the fan filter unit and the suction port, and the fan filter units are arranged in a line,
The fan filter 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 fan filter unit flows downward along the wall of the target space and then further flows along the wall and floor of the target space;
This relates to an air conditioning system for a clean room, characterized in that the main stream of air sent out from the fan filter unit towards the floor collides with the floor, flows along the surface of the floor due to the Coanda effect, and is guided along the floor in a desired direction perpendicular to the arrangement direction of the fan filter units.

The clean room air conditioning system of the present invention can be configured so that the air flow that is sent from the fan filter 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 fan filter unit or by a wall.

In the clean room air conditioning system of the present invention, a hanging wall extending downward from near the air outlet of the fan filter unit can be provided on the underside of the adjustment section.

The clean room air conditioning system of the present invention can reduce the area required for the installation surface of the fan filter unit while maintaining a sufficient level of cleanliness in the target space.

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; 2 is a schematic cross-sectional plan view of the air conditioning system of FIG. 1, taken along line II-II of FIG. FIG. 4 is a perspective view showing an example of a configuration of an adjustment unit. 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. 5 is a schematic plan view of the air conditioning system of FIG. 4, taken along line VV of FIG. 4. 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. 7 is a schematic plan view of the air conditioning system of FIG. 6, taken along line VII-VII of FIG. 6. 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. 1A and 1B show the results of simulating particle concentration in the air in an air conditioning system for a clean room according to the present invention, in which (A) shows the particle concentration distribution in the air in a cross section of space along the position of the equipment, and (B) shows the particle concentration distribution in the air 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. 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 11 represent the same items.

In this first embodiment, an adjustment unit 8 equipped with a fan filter unit 2 is installed in a wall area of the target space S. The adjustment unit 8 forms a space partitioned from the target space S inside, sucks in air in the upper part of the target space S as return air A2, and indirectly exchanges heat with a cooling medium such as cold water in the dry coil (cooling unit 6) to adjust the temperature, and sends it out as clean indoor air A1 from the fan filter unit 2. In other words, the adjustment unit 8 is functionally roughly equivalent to the space combined with the ceiling and the dry coil in the conventional example shown in FIG. 11. The adjustment unit 8 sucks in the heated and rising air in the upper part of the target space S as return air A2, but due to the hanging relationship with the vertical ceiling which is the structural body and the panel finish, it is economically preferable that the top end of the adjustment unit is hung lower than the vertical ceiling 10 of the target space S. The adjustment unit 8 draws in the heated and rising air at the top of the target space S as return air A2, but because the side of the suspended adjustment unit 8 is close to the vertical ceiling 10, the intake port 8b of the adjustment unit 8 is also close to the vertical ceiling 10, which is preferable.

In this first embodiment, the adjustment unit 8 is a box-shaped structure provided above the floor 13 at a level above the equipment (device) 5, with two rows provided, one along each of the walls 7, 7 that form the two opposing sides of the target space S in a plan view. An intake port 8b for drawing in air is provided on one side (front surface 8a) of the box-shaped adjustment unit 8. The intake port 8b opens into the target space S, and the internal space of the adjustment unit 8 is directly connected to the target space S.

A fan filter unit 2 is disposed on the underside 8c of the adjustment unit 8. The fan filter unit 2 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, and is configured to draw air from the adjustment unit 8 into the housing by the fan and blow it onto a filter that covers the entire lower part of the housing, and send the purified air downward as indoor air A1 into the target space S below. In JP 2019-090547, an example of a conventional invention by the applicant, the ceiling 1 configured as a dropped ceiling is used as the installation surface for the fan filter unit 2, but in this first embodiment, the underside 8c of the adjustment unit 8 is configured as the installation surface for the fan filter unit 2, and the area of the installation surface for the fan filter unit 2 is limited to the area near the wall.

In a plan view of the adjustment section 8, the fan filter unit 2 on the underside 8c is located on the opposite side to the suction port 8b on the front side 8a. A cooling unit 6, which is a dry coil, is provided inside the adjustment section 8 to separate the suction port 8b from the fan filter unit 2, and the air sucked in from the suction port 8b passes through the dry coil to be cooled before being sent out from the fan filter unit 2.

The lower surface 8c of the box-shaped adjustment section 8 is provided with a hanging wall 9 that extends downward from the periphery of the fan filter unit 2, and adjusts the direction of the air blown out from the fan filter unit 2 as described below. Thus, in this first embodiment, each adjustment section 8 may be configured as a unit that includes one fan filter unit 2 and one cooling unit 6 per box-shaped structure, and further includes an intake port 8b. Furthermore, since the planar dimensions of the HEPA filter are economically limited, each adjustment section 8 may be configured as a unit that includes multiple fan filter units 2, one cooling unit 6, and an intake port 8b per box-shaped structure depending on the air volume. Multiple fan filter units 2 may be arranged in parallel in the same direction to form a single mass.

In this specification, expressions such as "downward" and "sideways" are used in relation to air flow, 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 surface of the floor, but rather to the extent that it is generally along the surface of the floor. Similarly, expressions such as "perpendicular" and "horizontal" do not only mean that one direction and another direction form a right angle, or that it is exactly horizontal to the direction of gravity, but refer to an angle that can be expressed as "perpendicular" or "horizontal" in practice.

The adjustment unit 8 is installed at an appropriate height above the equipment 5 in the target space S, for example by hanging it from the ceiling 10. The ceiling 10 may be a vertical ceiling structure below the upper floor or roof slab, and dustproof measures such as dustproof paint may be applied to this, or it may be configured as a panel ceiling and the concrete pouring surface may be hidden to provide dustproof measures. In particular, in steel-framed buildings, the underside of the floor may be configured as a steel plate. In this case, dustproof measures such as gap treatment may be applied to the underside of the floor on the upper floor, and the ceiling 10 may be configured as a vertical ceiling. In this way, the cost of interior materials for the ceiling 10 can be reduced.

The setting of the area in which the adjustment units 8 are provided and the arrangement of the fan filter units 2 will be described. In this first embodiment, as shown in FIG. 2, the adjustment units 8 are provided in two rows along the walls 7 at both ends of the room which is generally rectangular in plan view. The fan filter units 2 are provided on the undersides 8c of the adjustment units 8, and the target space S as a whole has two rows of fan filter units 2 provided in a line along the two opposing walls, one row on each side.

The adjustment unit 8 has an intake port 8b on one side (front surface 8a) in plan view, and a fan filter unit 2 on the opposite side (other side); the adjustment unit 8 is positioned relative to the wall 7 so that the side on which the fan filter unit 2 is provided is close to the wall 7, and the intake port 8b is located on the opposite side of the wall 7 across the fan filter unit 2 in plan view. When viewed from the fan filter unit 2, the wall 7 is located on one side, and the intake port 8b is located on the other side, in a direction perpendicular to the direction in which the multiple fan filter units 2 are arranged in plan view.

The configuration of the adjustment unit 8 shown here is merely one example, and the form of the adjustment unit 8 and the type and form of the equipment included in the adjustment unit 8 are not limited to this. For example, although the dry coil is illustrated as being placed inside the adjustment unit 8, it may also be placed outside the suction port 8b. Also, if necessary, a humidifier (not shown) may be provided to adjust the humidity.

Unlike floor 3 in the above-mentioned conventional example shown in FIG. 11, floor 13 of the target space is not designed as a raised floor that allows air to circulate underneath floor 13. Equipment 5 such as production equipment is placed and operates on the upper surface of floor 13. Equipment 5 is production equipment that processes objects such as base material wafers that form semiconductor integrated circuits, substrates for flat panel displays, or containers that store these items. These pieces of equipment 5 are devices that give off a large amount of heat that they generate to the surrounding air, while maintaining the temperature within a specified range in areas that handle their own semi-finished products, etc.

As shown in FIG. 1, clean air is sent from the fan filter 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 fan filter unit 2, and in the other two directions, there is a downward flow of indoor air A1 sent out from another adjacent fan filter unit 2. Most of the indoor air A1 sent out downward from the fan filter 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, for the indoor air A1 sent out from the blower units 2 located at both ends of a plurality of fan filter 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 similarly flows in the remaining one direction). The downward indoor air A1 collides with the floor 13, and once a flow is formed along the surface of the floor 13 and its direction is determined, if there are no obstacles such as equipment 5 in the direction of the flow, the air flow along the floor surface will flow without peeling off the floor surface due to the Coanda effect. Here, the "target direction" is the direction of the area to which it is desired to supply the indoor air A1 as viewed from the fan filter unit 2, and in the case of a clean room such as this first embodiment, it is the direction of the area in which the equipment 5 is located. In terms of the drawing, it is the right for the fan filter units 2 arranged in the left column in the drawing, and the left for the fan filter units 2 arranged in the right column.

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 does not peel off the floor surface between the equipment 5 due to the Coanda effect, but crawls along the upper surface of the floor 13, receiving the exhaust heat from the equipment 5. As a result, some of the indoor air A1, which has become warmer as it collides with the equipment 5 and slows its crawling speed, receives more exhaust heat, and moves upward due to the density difference caused by the temperature difference. In this way, the air currents crawling along the floor surface due to the Coanda effect and the air currents heated by collisions with the equipment 5 form a temperature stratification on the floor 13 where the temperature is higher at higher positions and lower at lower positions, without being disturbed by the slow air flow speed throughout the room.

In this first embodiment, the adjustment unit 8 and the fan filter unit 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 the fan filter units 2 on both sides. The flow of the indoor air A1 along the floor 13 flows from positions along the walls 7 on both sides of the target space S to the opposite side of the walls 7, so that 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 indoor air A1 flowing along the floor 13 from both ends of the target space S travel along the floor 13 while absorbing the exhaust heat from the equipment 5, then collide with each other on the floor 13 in the center and begin to rise. The intake port 8b of the adjustment unit 8 is provided above the floor 13, and a portion of the indoor air A1 above the floor 13 is taken into the adjustment unit 8 from the intake port 8b as return air A2. At this time, the return air A2 is cooled to an appropriate temperature by a dry coil provided in the adjustment unit 8, and is then supplied to the target space S from the fan filter unit 2 as indoor air A1.

In addition, another part of the main flow of the indoor air A1 blown out from each of the adjustment units 8 along the walls 7 on both sides and flowing along the floor 13 collides with each other on the floor 13 in the center, where the dynamic pressure of each air flow regains static pressure and is further converted into dynamic pressure by changing direction, where it starts to rise. This change in direction allows the rising air current to rise without disturbing the stratified air conditioning layer. The intake port 8b of the adjustment unit 8 is provided above the floor 13, and some of the heated indoor air above the floor 13 is taken into the adjustment unit 8 from the communication port as return air A2. At this time, the return air A2 is cooled to an appropriate temperature by the dry coil provided in the intake port 8b, and is then supplied to the target space S as indoor air A1 from the fan filter unit 2.

In addition, another part of the indoor air A1 sent downward from the fan filter unit 2 rises without moving very far along the floor 13 due to collision with the floor 13 or receiving exhaust heat from the equipment 5, and is sucked in through the intake port 8b of the adjustment section 8. Here, as described above, the lower surface 8c of the adjustment section 8 is provided with a hanging wall 9 around the fan filter unit 2. If the hanging wall 9 was not provided, part of the indoor air A1 sent out from the fan filter unit 2 would be attracted by this air flow, causing a short circuit in which the air is sent out from the fan filter unit 2 and then taken back into the adjustment section 8 shortly after it is sent out. Such a short circuit is a wasteful movement from the viewpoint of supplying air in an appropriate state to the target area (in this case, the area around the equipment 5), and is energetically inefficient.

Therefore, if a hanging wall 9 is provided near the air outlet of the fan filter unit 2, the air flow sent downward from the fan filter unit 2 is prevented from mixing with the air flow rising in the area near the adjustment unit 8 in a plan view, thereby preventing the occurrence of a short circuit. Here, the hanging wall 9 is attached so as to surround the periphery of the air outlet of the fan filter unit 2, but the hanging wall 9 does not necessarily have to be provided so as to surround the entire periphery of the air outlet of the fan filter unit 2, and can be changed as appropriate depending on the surrounding conditions of the fan filter unit 2. For example, if the adjustment unit 8 is disposed close to a wall, the hanging wall 9 on the wall side may be omitted, or if the fan filter units 2 of the adjustment unit 8 are adjacent to each other at a close distance, the hanging wall 9 between the adjacent fan filter units 2 may be omitted. In these cases, it is considered that the occurrence of a short circuit can be prevented even without a hanging wall due to the presence of a wall or the air blown from the adjacent fan filter units 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 fan filter unit 2 installed at the end of the target space S flows along the upper surface of the floor 13, and when it reaches the center, it collides with each other and rises, and is sucked in through the suction port 8b and returns to the adjustment unit 8 as return air A2, and the return air A2 that has returned to the adjustment unit 8 is sent downward again from the fan filter unit 2 as indoor air A1, forming an air circulation in this form. In addition, in this air circulation, a part of the indoor air A1 flowing along the upper surface of the floor 13 receives exhaust heat from the equipment 5 on the way before reaching the center, and is heated, its density decreases and it rises, and it collides at the center and merges with the air flow that is rising above the floor 13. In the internal space of the adjustment unit 8, negative pressure is generated by the operation of the fan filter unit 2, and the above-mentioned air flow is driven by this pressure difference. In addition, in order to assist this air circulation, a blower such as a fan (not shown) may be provided in each place as necessary.

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. 11. In the conventional example of Fig. 11, in order to supply a generally downward airflow, even though it is a non-unidirectional airflow that dilutes and mixes widely in the target space S, a large-area ceiling 1 is constructed as a cell ceiling or panel ceiling, especially a cell ceiling, and a fan filter unit 2 is placed there. In the first embodiment shown in Figs. 1 and 2, adjustment units 8 are provided on both sides of the room, and the fan filter unit 2 is installed there, and a dropped ceiling that covers the entire upper part of the target space S is not necessary. In addition, in the area where the adjustment unit 8 is not provided, the height up to the ceiling 10 can be used, so more space can be used as a clean room compared to the example shown in Fig. 11, and it is easy to place, for example, tall devices and equipment. In addition, even if an existing building is used as an industrial clean room or the floor height of the building is low, it is easy to construct a clean room. In addition, the cost of installing a large-area cell ceiling and installing a dropped ceiling even though there is no ceiling transportation can be reduced. The space in which negative pressure occurs is also small, so the area on the structure that requires dust-proofing can be minimized.

In addition, in the first embodiment, temperature stratification is utilized to efficiently cool the target space S, particularly the height close to the floor 13, which requires air conditioning, and this is advantageous in terms of air conditioning efficiency. In the conventional example shown in FIG. 11, the indoor air A1 is supplied to the entire area of the target space S with a generally downward airflow, even though it is a non-unidirectional airflow that dilutes and mixes, so it was necessary to adjust the temperature to an appropriate level not only in the planar area but also in the height direction below the ceiling 1 where the fan filter unit 2 is installed, but in the case of the first embodiment, the return air A2 to be cooled is air recovered from a heat pool formed near the ceiling 10 above the equipment 5 on the floor 13 where the equipment 5 is placed. Since high-temperature air can be used as the cooling target, the temperature difference of the cooling medium in the dry coil can be made large, and the temperature of the cooling medium can be made high, so the coefficient of performance of the cooling source consisting of the compressor, expansion valve, evaporator, condenser, etc. that make up the refrigeration cycle can be increased, and the heat exchange efficiency is high. In addition, the number of dry coil rows can be reduced, reducing pressure loss and the energy required to transport the air, resulting in high heat exchange efficiency.

Furthermore, the indoor air A1 forms a temperature stratification, and the heated air automatically rises to the height of the adjustment unit 8 due to density differences. This movement drives part of the air circulation described above, so energy required for transporting the air can also be saved.

In addition, in this first embodiment, the Coanda effect is effectively utilized to allow the air supplied from the fan filter unit 2 to reach long distances. The indoor air A1 supplied to the target space S from the fan filter unit 2 is first sent downward and collides with the floor 13. The colliding indoor air A1 is redirected along the upper surface of the floor 13, and thereafter reaches a long distance from the fan filter unit 2 due to the Coanda effect, making it possible to efficiently deliver clean air to areas other than the equipment 5 located directly below the fan filter unit 2. This makes it possible to fully achieve a cleanliness level of around class 6, for example.

Figures 4 and 5 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 adjustment units 8 in which the fan filter units 2 are arranged are provided along 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 adjustment unit 8 is provided along a wall 7 that forms one side of the room, and the fan filter units 2 arranged there send out indoor air A1 toward the opposite wall 7 where the adjustment unit 8 is not installed.

When the adjustment section 8 and the fan filter unit 2 are arranged in this way, the indoor air A1 sent downward from the fan filter unit 2 collides with the floor 13, and as in the first embodiment shown in Figures 1 and 2, it 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), and is guided in the remaining direction (the direction in which the wall 7 on the opposite side as seen from the fan filter unit 2 is located), which is the desired direction. After that, it does not peel off the floor surface between the devices 5 due to the Coanda effect, and crawls along the top surface of the floor 13, receiving the exhaust heat from the devices 5. As a result, some of the indoor air A1, which has slowed down its crawling speed by colliding with the devices 5 and received more exhaust heat, and its temperature has risen, moves upward due to the density difference caused by the temperature difference.

In the area near the wall 7 on the opposite side where the adjustment unit 8 is not located, the main stream of the indoor air A1 sent from the fan filter unit 2 side and moving along the floor 13 collides with the wall 7 and starts to rise. Although it is the main stream here, as it moves toward the wall, some of the airflow that receives the exhaust heat and rises branches off many times, and the air volume itself is reduced. This main stream collides with the wall, and the dynamic pressure of each airflow is reacquired as static pressure, and the dynamic pressure conversion is further changed in direction, and here it starts to rise. With this change in direction, the rising airflow rises without disturbing the stratified air conditioning layer. In addition, a part of the indoor air A1 moving in the desired direction along the floor 13 receives the exhaust heat from the equipment 5 located along the way and rises, and merges with the air flow induced along the floor 13 and the wall 7 above the floor 13. The rising indoor air A1 is sucked back into the adjustment unit 8 through the suction port 8b of the adjustment unit 8. In this way, as shown in FIG. 4, an air circulation is created that is roughly half the air flow in the first embodiment (see FIG. 1), and the target space S, which is a clean room, is created in the same way as in the first embodiment.

Figures 6 and 7 show yet another example (third embodiment) of the 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 fan filter units 2 are arranged on the inner undersides 8c of adjustment units 8 along opposing walls 7 in a room that is generally rectangular in plan view, but in addition, a third row of adjustment units 8 is provided in the area corresponding to the center of the room.

The third row of adjustment units 8 are arranged in a direction parallel to the first and second rows of adjustment units 8 located at both ends of the room, and are positioned closer to the second row than the center in a direction perpendicular to the arrangement of the first and second rows of adjustment units 8, assuming that the left adjustment unit 8 in Figures 4 and 5 is the first row and the right adjustment unit 8 is the second row. The third row of adjustment units 8 are arranged so that the side with the suction port 8b (front side) faces the first row in a plan view, and the side with the fan filter unit 2 faces the second row.

The indoor air A1 sent out from the fan filter 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 fan filter unit 2, and the air is guided in the remaining desired direction (to the right). Similarly, the indoor air A1 sent out from the fan filter 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 fan filter unit 2, and the air is guided in the remaining desired direction (to the left).

The indoor air A1 sent out from the fan filter unit 2 in the third row (center) also collides with the floor 13 and changes direction, but in this case, of the four horizontal directions seen from the flow of the indoor air A1, in one direction there is a flow of indoor air A1 sent out from the fan filter 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 fan filter unit 2 in the same third row (with regard to the indoor air A1 sent out from the fan filter units 2 located at both ends of the third row, the flow of indoor air A1 flowing in from the fan filter unit 2 in the second row exists in one direction, the downward flow of indoor air A1 sent out from the adjacent fan filter unit 2 in the third row exists in one direction, and the wall 7 is located in yet another direction). The flow of indoor air A1, which changes direction along the floor 13, is blocked by these and is guided in the remaining one direction (leftward), which is the desired direction.

The flow of indoor air A1 sent out from the first row of fan filter 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 fan filter 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 airflow changes direction again above the floor 13 and flows toward the intake ports 8b of the first and third rows, and is sucked into the adjustment unit 8 from the intake ports 8b as return air A2.

When the flow of indoor air A1 sent out from the second row of fan filter units 2 and moving leftward along the upper surface of the floor 13 reaches the vicinity of the third row of fan filter units 2, there is a flow of indoor air A1 sent out downward from the third row of fan filter units 2 ahead. The flow of indoor air A1 sent out from the second row of fan filter units 2 changes direction and begins to rise. The rising airflow changes direction again above the floor 13 and flows toward the intake port 8b of the second or third row of adjustment unit 8, and is sucked into the adjustment unit 8 from the intake port 8b as return air A2.

In this way, for the indoor air A1 sent out from the first and third rows of fan filter 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 fan filter units 2, a circulation roughly similar to that of the second embodiment shown in Figures 4 and 5 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.

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 the indoor air A1 sent out from the fan filter unit 2. Specifically, first, the fan filter 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 fan filter 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 fan filter 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, rises, and is sucked into the adjustment unit 8 through the suction port 8b. By appropriately arranging the wall 7 or another 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 through the suction port 8b, thereby forming the air circulation as shown in Figures 1, 4, and 6. The main feature of the present invention is that the indoor air A1 is sent downward from the fan filter 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. However, 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, the flow of the indoor air A1 is guided by devising the arrangement of the fan filter unit 2 and the wall 7, and the circulation as described above is formed. In addition, the heat generated by the exhaust heat of the device 5 is used to drive a certain amount of indoor air A1 over long distances.

In this way, in each embodiment, by skillfully arranging the fan filter unit 2, walls 7, etc., it is possible to appropriately guide the flow of indoor air A1 in the desired direction with a simple configuration. Furthermore, even in a large clean room, by appropriately combining these, it is possible to supply clean air at an appropriate temperature to every corner of the target space. Furthermore, in addition to the air flow and walls 7, it is also possible to provide other objects or structures (such as a screen-like object) to guide the flow of indoor air A1.

Figures 8 to 10 show the results of a simulation of the air flow and conditions in a clean room designed based on the above-mentioned technical concept, with Figure 8 showing the distribution of air temperature, Figure 9 showing the concentration of particles in the air, and Figure 10 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 four pieces of equipment 5 are arranged in the left-right direction within the target space S, which is a clean room. The distance from the air outlet of the fan filter unit 2 provided in the adjustment section 8 on the left side of the figure to the wall 7 at the right end is set to approximately 20 m, and the heat load is calculated not only for the exhaust heat of the equipment 5 installed on the floor 13, but also for the heat generated by lighting and people (not shown). In addition, multiple pieces of equipment 5 are arranged in the depth direction (direction perpendicular to the paper surface), but this is not shown in the figure.

An adjustment unit 8 is provided above the left end of the target space S, and air is sent downward from the fan filter unit 2 arranged on the underside 8c, collides with the floor 13, and proceeds toward the right end of the target space S. An intake port 8b is provided in the adjustment unit 8 located above the floor 13, and air that collides with the wall 7 at the right end of the target space S rises above the floor 13 before being taken in by the intake port 8b.

In FIG. 8, areas with higher air temperatures are displayed in black, and areas with lower air temperatures are displayed in white. First, referring to (B), it can be seen that air circulates well in the cross section where no equipment 5 is present, and that light-colored (low-temperature) air reaches the center of the target space S at a height near the floor 13. Dark-colored (high-temperature) air forms a heat pool above the target space S, and this is taken in from the intake port 8b as return air. Also, referring to (A) of FIG. 8, it can be seen that even though the equipment 5 is arranged in the direction of air circulation, air slips through between them, and light-colored (low-temperature) air reaches the right edge. It can be seen that the light-colored (low-temperature) air is also distributed between the equipment 5, and that low-temperature air is supplied by successfully getting around between the equipment 5.

Next, we refer to Figure 9, which shows the particle concentration distribution in the air. In Figure 9, areas with higher particle concentration are displayed in black, and areas with lower particle concentration are displayed in white. In (B), in the cross section where the equipment 5 is not present, it can be seen that low-concentration air reaches the right-hand edge area along the floor surface. Also, in (A) of Figure 9, air with a high particle concentration can be seen stagnating near the equipment 5, which is the second from the right, but the particle concentration is low in the right-hand edge area, and it can be seen that clean air reaches the opposite end of the fan filter unit 2.

Refer to Figure 10, which shows the distribution of air age. In Figure 10, for the air sent out from the fan filter unit 2, areas with higher air age are displayed in black, and areas with lower air age are displayed in white. In both (A) and (B), the area with low air age near the floor surface on which the equipment 5 is placed continues to the right end, and it can be seen that the air age is kept low throughout the target space S (i.e., air is circulated efficiently).

When the air was blown out of the fan filter unit 2 at a height of 1,200 mm from the floor surface at a setting of 23° C., the temperature was about 25.5° C. near the right end wall 7, and the average value at a height of 1,200 mm was 25.0° C. The particle concentration at the same height was about 746 particles/m ³ near the outlet of the fan filter unit 2, about 2,790 particles/m ³ near the right end wall 7, and about 2,700 particles/m ³ on average at a height of 1,200 mm. The age of the air was about 93.2 seconds near the right end wall 7 at a height of 1,200 mm, and about 55.6 seconds on average. Thus, the results of this simulation showed that even if the equipment 5 is placed on the floor surface, it is possible to supply air with a young age, clean air, and a sufficiently low temperature to a position far from the outlet at a required height in the target space S. In terms of cleanliness of a clean room, it is fully possible to achieve up to about class 6.

In this way, the air conditioning system of this embodiment is equipped with an adjustment section 8 with a fan filter unit 2 on the underside 8c and an intake port 8b on the front surface 8a, and supplies air from the fan filter unit 2 toward the floor surface. The air supplied from the fan filter unit 2 is delivered far enough by utilizing the Coanda effect, while the heat from the equipment 5 is successively diverted and received, and separated as an ascending air current, forming temperature stratification throughout the room.

As described above, the air conditioning system for the clean room in each of the above embodiments comprises: a target space S in which is installed a device (equipment) 5 that needs to maintain its own temperature within a predetermined range while providing a thermal load to the surrounding air; an adjustment unit 8 that is provided above the floor 13 and partitioned off from the target space S, forming a space at a level above the device (equipment) 5; a fan filter unit 2 that is provided on the underside 8c of the adjustment unit 8 and sends air (room air) A1 downward toward the floor 13; a dry coil that is provided on the side of the adjustment unit 8 and controls the temperature of the air by circulating it as the fan filter unit 2 operates; and an intake port 8b that connects the internal space of the adjustment unit 8, the target space S, and the side of the adjustment unit. The adjustment unit 8 is configured as a box-shaped structure equipped with the fan filter unit 2 and the intake port 8b, and the flow of air A1 sent from the fan filter unit 2 toward the floor 13 is configured to be guided along the floor 13 in a desired direction perpendicular to the arrangement direction of the fan filter units 2. In this way, the area of the installation surface of the fan filter unit 2 can be limited to the underside 8c of the adjustment section 8, while utilizing the Coanda effect and temperature stratification to suitably supply the air A1 sent out from the fan filter unit 2 into the target space S.

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

In the clean room air conditioning system of each embodiment, a hanging wall 9 is provided on the underside 8c of the adjustment section 8, extending downward from near the air outlet of the fan filter unit 2. In this way, the flow of air A1 sent downward from the fan filter unit 2 is prevented from mixing with the flow of air A1 ascending in the nearby area, thereby preventing the occurrence of a short circuit.

Therefore, according to each of the above embodiments, it is possible to reduce the area required for the installation surface of the fan filter unit 2 while maintaining a sufficient level of cleanliness in the target space.

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 Fan filter unit 5 Device (equipment)
6 Dry coil (cooling unit)
7 Wall 8 Adjustment section 8b Intake port 8c Underside 9 Hanging wall 13 Floor A1 Air (room air)
S Target Space

Claims (3)

a target space in which a device that needs to maintain its own temperature within a predetermined range while providing a thermal load to the surrounding air is installed;
An adjustment unit provided above the floor, partitioned from a target space, and forming a space at a level above the device;
a fan filter unit provided on a lower surface of the adjustment unit and configured to blow air downward toward the floor;
a dry coil provided on a side surface of the adjustment unit, the dry coil regulating the temperature of air by circulating the air through the fan filter unit;
A suction port is provided on a side surface of the adjustment unit and communicates an internal space of the adjustment unit with a target space,
The adjustment section is configured as a box-shaped structure including the fan filter unit and the suction port, and the fan filter units are arranged in a line,
The fan filter 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 fan filter unit flows downward along the wall of the target space and then further flows along the wall and floor of the target space;
1. An air conditioning system for a clean room, characterized in that a main stream of air sent out from the fan filter unit toward the floor collides with the floor, flows along the surface of the floor due to the Coanda effect, and is guided along the floor in a desired direction perpendicular to the arrangement direction of the fan filter units. 2. The air conditioning system for a clean room as described in claim 1, characterized in that the air flow sent out from the fan filter unit toward the floor and guided along the floor is guided in a desired direction by having its horizontal direction blocked by an air flow sent out from another fan filter unit or by a wall. 2. The air conditioning system for a clean room according to claim 1, wherein a hanging wall is provided on a lower surface of the adjustment section, the hanging wall extending downward from a vicinity of the air outlet of the fan filter unit.

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