JP2020183820A - Clean room air conditioning system - Google Patents

Abstract

To provide a clean room air conditioning system capable of suppressing an increase in the cost, saving energy, and making effective use of an object space while satisfying a temperature and a cleanliness factor as required in the object space.SOLUTION: A clean room air conditioning system includes a clean room 1 into which air from a ceiling plenum chamber 5 flows, an underfloor chamber 6 into which air from the clean room flows, where the air exhausted from the underfloor chamber is returned via a return shaft 11 to the ceiling plenum chamber, and further includes air cooling means 8, supply air temperature sensors 13, and a control device for controlling the velocity of air blown out of a group of fan filter units 7 provided on the ceilings of corresponding small areas on the basis of measurement values measured by respective indoor small-area temperature sensors 12 which measure indoor temperatures in respective small areas divided in the vertical direction, and controlling the outlet temperature of the air cooling means on the basis of measurement values of the supply air temperature sensors.SELECTED DRAWING: Figure 1

Description

The present invention relates to a clean room air conditioning system, and more particularly to a large space clean room air conditioning system used in a semiconductor factory, a factory that manufactures films, liquid crystals, organic EL, etc. used for a flat panel display, or a precision machinery factory. In particular, the present invention relates to an air conditioning system that reduces running costs while finely controlling the room temperature so that temperature unevenness does not occur in a clean room.

In semiconductor factories, factories that manufacture films, liquid crystals, organic EL, etc. used for flat panel displays, or precision machinery factories, even a small amount of suspended fine particles adheres to the product being manufactured and causes product defects. We strive to improve the quality and reliability of our products and improve yields by keeping the entire factory or work room clean as needed.
Recently, the concept of mini-environment or micro-environment, which locally cleans only the area where semi-finished products or products are manufactured or transported between processes, has become widespread. Actually, it is a technical idea that the space where semi-finished products and products are exposed is isolated from others as a small space, and the inside of the small space is locally kept highly clean, and it is introduced in production equipment and inter-process transportation. .. In this method, the area that secures particularly high cleanliness even in a clean room is locally limited, and the other areas are not required to have as high cleanliness as in the past, so it is sufficient to maintain a certain degree of cleanliness for the entire room. become. In this way, large spaces (ballrooms) have become the mainstream of industrial clean rooms.
Even in such a large space (ballroom) type clean room, although it is different from the old power-hungry whole area downflow, the ceiling with a HEPA filter as the final part of the ceiling so that the air flow generally flows from top to bottom. Air is sucked under the floor between the slab floor and the raised floor through the opening of the raised floor formed by punching panels, etc., and the air is temperature-controlled and dust is removed from the ceiling again to blow out. Forming a flow. In this way, the dust generated in the room is quickly eliminated.

As shown in FIG. 5, the conventional clean room is provided in a building K having a certain degree of airtightness such as a semiconductor factory, and the ceiling slab K1 of the building K and the ceiling of the clean room 1 in which a lattice is formed by T bars and channel materials. A ceiling plenum chamber 5 composed of two, an underfloor chamber 6 composed of the floor 4 of the clean room 1 and the floor slab K2 of the building K, and a wall K3 and a board that ensure the airtightness of the building K. The retan shaft 11 formed between the side wall 3 of the clean room 1 formed by the panel, the fan filter unit (FFU) 7 sparsely provided in the lattice of the ceiling 2 of the clean room 1, and the other lattice are fitted. It is composed of a blank panel to be used and an air cooling means 8 for cooling the air in the clean room 1.
Then, in order to secure a predetermined cleanliness of the air in the ceiling plenum chamber 5 by removing dust in the air with the fan filter unit 7, after the air volume is adjusted at the time of new installation so that a constant air volume can be secured, the air volume is maintained at that air volume. The air A1 that continues to move and is cleaned and blown into the clean room 1 is discharged from the discharge port such as the opening of the punching panel of the floor 4 that constitutes the floor by raising it on the floor slab K2. After being cooled by the air cooling means 8, the air flows through the retan shaft 11 to the ceiling plenum chamber 5 by the conveying force of the fan of the fan filter unit (FFU) 7.
Although it is difficult to see in the figure, the space of a large space (ballroom) clean room is large, and the image of the length of three fan filter units 7 for one of the air cooling means 8 shown in FIG. 1 is actually 25 to 30 m. It is the length of. That is, each of the air cooling means 8 which is a dry coil divides the inside of the clean room 1 into a plurality of areas in the lateral direction, and the air cooled by one air cooling means 8 circulates in the large area.

Since the temperature inside the clean room is a ballroom system, it is a little relaxed compared to the room exposed by old products, but even so, the tolerance may be as severe as ± 1 ° C for the 23 ° C setting, for example. .. This room temperature is set after cooling against the heat generated by the maximum load so that the set value of 23 ° C can be maintained anywhere in the room even if the production equipment operates and there is heat generated in the room as a heat load. In other words, it is equipped with the capacity of the equipment so that the temperature can be maintained at 23 ° C. when the air returns from the outlet of the floor 4.
Therefore, the air temperature of the ceiling blowout becomes much lower than 23 ° C. when the indoor heat load is large, and becomes a low temperature approaching 23 ° C. when the load is small.
As described above, in the conventional clean room air-conditioning system, one air cooling means 8 is actually in charge of a large area of lateral division having a depth of 25 to 30 m, and the air cooling means 8 flows through one proportional control valve. Since it is controlled, the flow rate of the heat medium of the proportional control valve is controlled by the calculation signal based on the deviation between the measured value of the detection temperature sensor at one point and the temperature set value (for example, the 23 ° C set value) in a large area. ..

In Patent Document 1, first, in a conventional air-conditioning system for a clean room, the room temperature at one point or a plurality of points is detected by a temperature sensor, average processing is performed even at a plurality of points, and then one generated signal is transmitted, and the signal is used. When controlling the cooling heat exchange amount of the air conditioner and changing the temperature of the air conditioning air to be supplied to control the room temperature, the temperature of the air conditioning air is set with the detection temperature averaged at one or more points as the representative temperature. We are paying attention to the drawback that the temperature unevenness in the large area of the clean room is further promoted because of the change.
For example, since there is a mixture of a part in a large area where a device that generates heat is installed and a part where a device that generates heat is not installed, the temperature is always higher or lower than the temperature detected by the temperature sensor. There is an area, that is, temperature unevenness.
Therefore, in the conventional air conditioning system, the temperature becomes higher in the area where the temperature is high, and the temperature becomes lower in the area where the temperature is low, so that the temperature unevenness in the indoor area is further promoted. Has raised the issue.
Therefore, in Patent Document 1, in addition to the circulating air flow by the fan filter unit, an air conditioner that sucks air from under the floor and blows out air conditioning air into the space behind the ceiling is provided separately, and a large area for each air conditioner in the room is vertically arranged. The temperature of the indoor air sensor installed in each small area is divided into small areas, and each small area is equipped with an air volume adjustment damper in the branch air supply duct in the ceiling space where the main air supply duct from the air conditioner is branched. The opening / closing rate of the air volume adjustment damper is controlled based on the deviation between the measured value and the set value, and the main return duct to the air conditioner is branched into each small area in the underfloor space. Each return air duct is equipped with an air volume adjustment damper, and temperature unevenness is controlled by controlling the opening / closing rate of the air volume adjustment damper under the floor based on the deviation between the temperature measurement value and the set value of the indoor air sensor installed in each small area. The technology to solve the problem is disclosed. (Patent Document 1).

Japanese Patent No. 3503265

In the clean room of Patent Document 1, a large number of fan filter units installed on the ceiling form a conveying force to convey the air flow for maintaining a clean state in the room, and the air flows from all the fan filter units. Air is blown into the clean room all at once at the same wind speed (air volume). Apart from this, an air conditioner with a built-in fan flows the temperature-controlled air with a different air volume and a different carrying force. The source of the temperature control air blown out from the branch air supply duct and the circulating air circulated by the fan filter unit and brought to the attic space are mixed at the suction port of the fan filter unit and blown out into the room, so it is small. In the area, each fan filter unit located there aims at the same blowout temperature, but the mix of temperature controlled air and circulating air may differ for each fan filter unit, eliminating the risk of temperature unevenness. Not.
In order to make the best use of the conventional clean room of FIG. 5, the addition of the air conditioner 12, the air supply duct 20, and the return air duct 50 provided in Patent Document 1 is not realistic because of major modifications.
In a normal ballroom type clean room, it is necessary to ventilate and circulate the air cooling means 8 which is a dry coil only by the conveying force of the fan filter unit 7. However, the temperature of the air flowing in the ceiling chamber is actually the non-uniformity of the passing air velocity in the entire heat transfer area when passing through the air cooling means 8, and the heat transfer portion of the heat exchange of the air cooling means 8. Due to the non-uniformity of the refrigerant temperature due to the above, the airflow temperature in the ceiling after passing through the retan shaft is not uniform from place to place, and the temperature of the airflow depends on the place such as where the air easily flows and where it stays. Because many fan filter units blow out air of different temperatures, the temperature of the air in the clean room is uneven, and even if the temperature sensor setting point, which is the typical temperature, is good, the clean room It affects the products produced in the company due to the temperature unevenness.

The present invention has been made in view of such circumstances, and in order to make the temperature variation in the entire clean room uniform, the inside of the clean room is not only divided into large areas for each air cooling means, but also. The large area covered by one cooling means is further divided into small areas consisting of a plurality of groups in the vertical direction, and an indoor temperature sensor for measuring the temperature in each group of the small area is provided to measure the indoor temperature sensor. By controlling the wind speed of the fan filter unit sent to each group based on the above, the temperature of the air flowing in each group is made uniform, and a temperature sensor for cooling means for measuring the outlet air temperature of the air cooling means is provided. By controlling the opening degree of the control valve of the air cooling means based on the measured value of the temperature sensor for the cooling means, the heat load of the entire large area can be covered and the heat load can be covered.
An energy-saving clean room air conditioning system is provided by calculating the average value of the wind speed from the fan motor frequency of each fan filter unit sent to each group and lowering the set value of the temperature sensor for the cooling means in order to reduce the average wind speed. The purpose is to do.

In order to achieve the above object, the present invention is a clean room air conditioning system for making the temperature of air in a clean room uniform, and is characterized by having the following configuration.
<1> The underfloor is provided with a ceiling plenum chamber 5, a clean room 1 in which a production device 20 into which air from the ceiling plenum chamber 5 flows is arranged, and an underfloor chamber 6 into which air from the clean room 1 flows. A clean room air conditioning system that returns the air discharged from the chamber 6 to the ceiling plenum chamber 5 via the retan shaft 11.
A fan filter unit 7 provided on the ceiling 2 of the clean room 1 to supply clean air to the clean room 1 and provide air with a transport force for returning air from the underfloor chamber 6 to the ceiling plenum chamber 5 via a retan shaft 11.
An air cooling means 8 that is provided at a position where air discharged from the underfloor chamber 6 and returned to the retan shaft can pass and cools the air returned to the ceiling plenum chamber 5.
A small area is set in which the direction in which the ceiling plenum chamber 5 of the air blown into the clean room 1 travels is the vertical direction and the clean room 1 is divided in the vertical direction, and the room temperature is measured for each small area. Area temperature sensor 12 and
An air supply temperature sensor 13 that measures the outlet air temperature of the air cooling means 8 in a one-to-one correspondence with the operator that adjusts the heat exchange amount of the air cooling means 8.
Of each small area divided in the vertical direction, it is provided on the ceiling 2 of the corresponding small area based on the measured value measured for each of the indoor small area temperature sensors 12 that measure the indoor temperature in each small area. A control device 33 that controls the blown air velocity of the group of the fan filter unit 7 and controls the outlet temperature of the air cooling means 8 according to the deviation from the set value based on the temperature measurement value of the air supply temperature sensor 13. A clean room air conditioning system characterized by being equipped with.

〈５〉前記風速の平均値の演算が、下記式によりなされることを特徴とする前記〈２〉に記載のクリーンルーム空調システム。

<2> The control device is a fan filter unit 7 provided on the ceiling 2 of the corresponding small area based on the measured value obtained by measuring the indoor temperature in each small area with the indoor small area temperature sensor 12. Using the fan motor inverter as an operator, the frequency is output to the group as a signal of the blown wind speed, and the blown wind speeds of all the small areas are multiplied by the area of each small area and added up, and the average blown wind speed is calculated separately. Then, the supply air temperature is variably controlled by separately controlling an operator for adjusting the heat exchange amount of the air cooling means 8 so that the average blown wind speed value becomes the target average wind speed. The clean room air conditioning system according to <1>.
<3> The indoor small area temperature sensor 12 can transmit a measured value signal wirelessly, and is provided with a receiving master unit on the ceiling side, and the air supply temperature sensor 13 is characterized in that the measured signal is transmitted by wire. The clean room air conditioning system according to the above <1> or the above <2>.
<4> The clean room air-conditioning system according to <2>, wherein the calculation of the average value of the wind speed is performed by the following formula.

<5> The clean room air-conditioning system according to <2>, wherein the calculation of the average value of the wind speed is performed by the following formula.

The clean room air-conditioning system according to the present invention includes a ceiling plenum chamber, a clean room in which a production device into which air from the ceiling plenum chamber flows is arranged, and an underfloor chamber into which air from the clean room flows, and from the underfloor chamber. A clean room air conditioning system that returns the discharged air to the ceiling plenum chamber via the retan shaft, supplies clean air to the clean room provided on the ceiling of the clean room, and air from the underfloor chamber via the retan shaft. A fan filter unit 7 that gives air a conveying force that returns to the ceiling plenum chamber and a position that allows air that is discharged from the underfloor chamber and returns to the retan shaft can pass through are provided to cool the air that is returned to the ceiling plenum chamber. A small area is set in which the air cooling means and the ceiling plenum chamber of the air blown into the clean room travel in the vertical direction, and the clean room is divided in the vertical direction, and the room temperature is measured for each small area. It is vertically separated from the indoor small area temperature sensor and the supply air temperature sensor 13 that measures the outlet air temperature of the air cooling means in a one-to-one correspondence with the operator that adjusts the heat exchange amount of the air cooling means. Of each small area, a group of fan filter units provided on the ceiling of the relevant small area based on the measured values measured for each of the small indoor area temperature sensors that measure the indoor temperature in each small area. Since it is provided with a control device that controls the blown air velocity and controls the outlet temperature of the air cooling means according to the deviation from the set value based on the temperature measurement value of the air supply temperature sensor.
Based on the temperature measurement data of the indoor small area temperature sensor, the rotation speed of each fan filter unit is controlled by the PID calculation result, and the wind speed of the wind blown from the fan filter unit into the clean room is also PID controlled to cool the air. In a large area in a clean room where the airflow is roughly divided by means, the temperature inside the clean room, which actually had a flat temperature distribution, can be controlled completely uniformly, and in the clean room. It is possible to prevent the influence on the products being produced.

Further, in the clean room air conditioning system according to the present invention, the control device is provided on the ceiling of the corresponding small area based on the measured value obtained by measuring the indoor temperature in each small area with each of the indoor small area temperature sensors. The frequency of the fan motor is used as an operator to output the frequency as a signal of the blown wind speed to the group of fan filter units, and the blown wind speeds of all the small areas are multiplied by the area of each small area and totaled, and the average is obtained. The air supply temperature is variably controlled by separately calculating the blown wind speed and separately controlling the operator that adjusts the heat exchange amount of the air cooling means so that the average blown wind speed value becomes the target average wind speed. Even if the air blown from each fan filter unit group into the clean room can be made uniform by changing each small area in terms of temperature equalization, the clean room as a whole calms down with too much air volume. The air cooling means is used to return the air to the ceiling plenum chamber so that the temperature inside the clean room can be maintained even if the average wind speed is lowered to the target average wind speed, which is set separately for energy saving, to prevent the harmful effect of increasing the power consumption. By lowering the set value of the supply air temperature to further cool the air to be supplied, the amount of heat transported by the unit air volume can be increased, and as a result, the average wind speed of the clean air blown from each fan filter unit into the clean room can be reduced. It can and energy saving can be achieved.
And since the indoor small area temperature sensor can transmit the measured value signal wirelessly and has a receiving master unit on the ceiling side, recently, a temperature sensor with wireless transmission with a built-in battery power supply is available at low cost. If this is used for a large number of indoor small area temperature sensors, the initial cost can be omitted because no wiring work for control related to the indoor temperature sensors is required, and one receiving master unit can use multiple indoor small area temperature sensors. Since it can be processed all at once, the control wiring inside the ceiling can be easily installed.

It is a schematic block diagram of the clean room which concerns on embodiment of this invention. It is a top view of the clean room which concerns on embodiment of this invention. It is explanatory drawing explaining the air volume control in the clean room which concerns on embodiment of this invention. It is a control block diagram of the clean room which concerns on embodiment of this invention. It is a schematic block diagram of a conventional clean room.

1 is a schematic configuration diagram of a clean room according to an embodiment of the present invention, FIG. 2 is a plan view of a clean room according to an embodiment of the present invention, FIG. 1A is a plan view of the entire clean room, and FIG. 2B is a plan view of one area. It is an enlarged plan view for explanation. FIG. 3 is an explanatory diagram of air volume control in a clean room.
In FIGS. 1 to 3, K is a building equipped with a large space clean room used in a semiconductor factory, a factory that manufactures films, liquid crystals, organic EL, etc. used for flat panel displays, or a precision machinery factory, and K1 is a ceiling slab of building K. (Or the floor slab on the upper floor), K2 is the floor slab of building K, K3 is the outer wall of building K and the fireproof partition wall in the room, 1 clean room, 2 is the ceiling, 3 is the side wall, 4 is the floor, and 5 is the ceiling plenum chamber. , 6 is an underfloor chamber, 7 is a fan filter unit (FFU), 8 is an air cooling means (dry coil), 9 is a pipe, 10 is a proportional control valve (two-way valve), 11 is a retan shaft, and 12 is a small indoor area. A temperature sensor (hereinafter referred to as an indoor small area temperature sensor), 13 is a supply air temperature sensor, 14 is a large area, and 20 is a production device.
In the embodiment of the present invention, a wireless indoor small area temperature sensor is used.

In this embodiment, the clean room 1 is installed and used in a building K such as a semiconductor factory, a factory that manufactures films, liquid crystals, organic EL, etc. used for a flat panel display, or a precision machinery factory.
The ceiling plenum chamber 5 is configured between the ceiling slab K1 of the building K and the ceiling 2 of the clean room 1, and the underfloor chamber 6 is configured between the floor 4 of the clean room 1 and the floor slab K2 of the building K. To.
In the clean room 1, a production device 20 for manufacturing a product or a semi-finished product in the middle of the product is arranged in the factory, and the ambient air is erected in the ambient environment to which the clean air from the ceiling plenum chamber 5 is supplied. The space where semi-finished products and products are exposed may be isolated from others as a small space, and the space inside the small space may be locally kept highly clean, with a mechanism for further purification.
Further, the air in the clean room 1 is configured to flow into the underfloor chamber 6 through, for example, a punching panel or a grating hole that constitutes the floor of the clean room 1. The air that has flowed into the underfloor chamber 6 from the clean room 1 is discharged to the ceiling plenum chamber 5 via a retan shaft 11 composed of the side wall 3 of the clean room 1 and the wall K3 of the building K, and a fan filter described later. Reflux is performed by the conveying force of the fan of the unit 7.
In the present embodiment, the floor 4 of the clean room 1 is made of a porous material for passing the air A1 in the clean room 1, but even if the floor is not made of the porous material, the outlets of the air A1 are separately arranged. It may be installed in the form.

In the present invention, the clean room 1 is arranged between the ceiling plenum chamber 5 and the underfloor chamber 6 as described above.
A grid is formed in the ceiling 2 of the clean room 1 with, for example, a T-bar or a channel material, and a fan in the casing and a motor driven by the fan and adjusted to a variable speed by an inverter or the like are formed in the opening 2a of the grid. A high-performance filter such as a HEPA filter is built in the lower part of the filter, the air in the ceiling plenum chamber 2 is taken into the casing, dust and the like are removed by the high-performance filter, and the purified air is introduced into the clean room 1. A large number of fan filter units 7 to be supplied are provided, although they are sparse, rather than the entire grid. When a lattice is formed of a T-bar or a channel material, a blank panel is fitted in the remaining lattice to block it.

In the present invention, the air cooling means 8 is installed in the middle of the air cooling means 8 by forming an air passage between the side wall 3 of the clean room 1 and the wall K3 of the building K when cooling while circulating a large amount of air like a clean room. It is often a dry coil (heat exchanger with a temperature that does not cause condensation on the surface), which is a bare air-water heat exchanger. Cold water is cooled by a refrigerator on the tube side of the dry coil and circulated by a pump. Is supplying a cold heat medium.
The air cooling means 8 is installed at a position where the air discharged from the underfloor chamber 6 and returned to the retan shaft 11 can pass through.
Then, in the present embodiment, the cooling means 8 is installed at the same level as the floor 4 in the retan shaft 11 through which the airflow discharged from the underfloor chamber 6 of the clean room 1 flows.
A pipe 9 is connected to the cooling means (dry coil) 8, and the pipe 9 is provided with a proportional control valve 10 capable of controlling the amount of cold water supplied to the dry coil 7 by opening and closing the valve.

In the present embodiment, the retan shaft (air passage) 11 is formed between the wall K3 of the building K and the side wall 3 of the clean room 1, passes through the floor 4 of the clean room 1, and enters the underfloor chamber 6. The flowing air A1 gradually merged in the underfloor chamber 6 from a place far from the retan shaft 11 (A2), and then collided with the wall K3 of the building K and changed its direction to literally lift up the inside of the retan shaft 11 as return air. After that, it flows to the ceiling plenum chamber 5 (A3).
Further, in the present invention, one wireless indoor small area temperature sensor 12 is provided in each small area in the clean room 1, and a wired air supply temperature sensor 13 corresponding to the large area 14 is provided.

Then, from the outside air harmonizer (not shown), the outside air that has been temperature-controlled, dust-removed, and sent through the duct is supplied to, for example, the ceiling plenum chamber 5 of the building K by an outside air duct (not shown), or for example. , It is supplied to the retan shaft 11 or the underfloor chamber 6 by an outside air duct (not shown), mixed with the surrounding circulating air by the transport force of the fan of the fan filter unit 7, and the purified air A1 is supplied into the room of the clean room 1. It has become so.
The air A1 supplied into the room of the clean room 1 is discharged to the underfloor chamber 6 via the floor 4. The air A2 discharged to the underfloor chamber 6 is sent out to the ceiling plenum chamber 5 through the retan shaft 11, cleaned again by the fan filter unit 7, and supplied into the clean room 1.
In this way, the air A1, A2, and A3 in the building K form an air circulation system that circulates the ceiling plenum chamber 5, the clean room 1, the underfloor chamber 6, and the retan shaft 11 in one direction while maintaining a predetermined cleanliness. doing.

2A and 2B are plan views of a clean room according to an embodiment of the present invention, FIG. 2A is a plan view of the entire clean room, and FIG. 2B is an enlarged plan view for explaining one area.
In the embodiment of the present invention, the clean room 1 is a dry coil which is an air cooling means (8) arranged near an outer wall K3 in a plurality of large areas 14 (area a, area b, area c, ...). Each large area 14 is further divided into a plurality of small areas (small area 1, small area 2) in the direction of the air flow flowing away from the dry coil in the ceiling plenum chamber (5). , Small area 3). The division of the large area 14 and the division of the small area are not particularly limited to exactly the same area, and each dry coil grouped for each process having a different heat generation load is divided according to the temperature change tendency in the clean room 1. Furthermore, it is preferable to classify small areas according to the airflow condition on the retan shaft and the group condition according to the size and shape of the heat transfer area of the dry coil, because it is possible to respond to temperature changes with higher accuracy.
Then, in the small area further divided into each of the divided large areas 14, a wireless indoor small area temperature sensor 12 is installed for each small area, the temperature of each small area is measured, and the temperature is measured via the master unit 31 described later. Then, the temperature measurement data is sent to the control device 33.
The wired air supply temperature sensor 13 is installed on the air wake side of the air cooling means 8 of the retan shaft 11 and measures the temperature after passing through the air cooling means 8 to the large area 14 to measure the wireless temperature. Similar to the indoor small area temperature sensor 12, the temperature measurement data is sent to the control device 33.

FIG. 3 is an explanatory diagram for explaining air volume control in the clean room according to the embodiment of the present invention, and FIG. 4 is a diagram showing a control means for the air conditioning system of the clean room according to the embodiment of the present invention.
In the figure, 31 is a master unit of a wireless temperature sensor, and 33 is a control device.
Hereinafter, an example of control of the air conditioning system of the clean room according to the embodiment of the present invention will be described with reference to FIGS. 3 and 4.

In the embodiment of the present invention, the set temperature in the clean room 1 is set to 23 ° C. ± 1.5 ° C. (allowable range) as an example of the indoor design conditions.
The wireless indoor small area temperature sensor 12 installed in each small area (small areas 1 to 4) constituting the large area 14 sets the temperature of each of the small areas (1 to 4) at predetermined intervals (for example, several μ). It detects every second to several minutes), puts it on a radio wave or other wireless communication means, and sends the temperature measurement data to the master unit 31. The temperature measurement data is transmitted from the master unit 31 to the control device 33 by wire.
The control device 33 determines the deviation between the sent indoor small area temperature measurement data and the indoor temperature set value (for example, SP = 23 ° C.) in each small area recorded in the recording unit of the control device 33. Based on this, the calculation is performed using Yn (n = 1, 2, ...) Of the following equation 1, and the fan motor of the fan filter unit 7 for each small area is calculated so that the temperature of each small area approaches the temperature set value. The inverter frequency is PID controlled, and the wind speed of the wind blown from the fan filter unit 7 is controlled. The PID control referred to here controls the actuator by the output signal of the result of calculation including at least one of I (integration time) and D (differential time) in addition to the P operation including at least P (proportional band). To do.
The above flow is performed for the small areas 1 to 4 in the large area (14).

For example, in the small area 1, the rotation speed of the fan filter unit 7a of the group is PID controlled so that SP = 23 ° C., and in this small area 1, the air temperature in the ceiling plenum chamber is relatively high. Alternatively, when the indoor heat generation load is high, for example, the wind speed of the blown air is set to 0.45 m / s.
Similarly, in the small area 2, the rotation speed of the fan filter unit 7b of the group is PID controlled so that SP = 23 ° C., and in this small area 2, the air temperature in the ceiling plenum chamber is small area 1. It is lower but relatively high, or the indoor heat generation load is lower than small area 1 but relatively high. For example, the wind speed of the blown air is set to 0.35 m / s.
Then, in the small area 3, the rotation speed of the fan filter unit 7c of the group is PID controlled so that SP = 23 ° C., and in this small area 3, the air temperature in the ceiling plenum chamber is higher than that in the small area 2. It is a little low, or the indoor heat generation load is relatively lower than that of the small area 2. For example, the wind speed of the blown air is set to 0.30 m / s.
Further, in the small area 4, the rotation speed of the fan filter unit 7d of the group is PID controlled so that SP = 23 ° C., and in this small area 4, the air temperature in the ceiling plenum chamber is relatively low. Alternatively, when the indoor heat generation load is relatively low, for example, the wind speed of the blown air is 0.25 m / s.
By such a procedure, the temperature in each small area is maintained at 23 ° C.

By the way, the control device 33 has a one-to-one correspondence with the proportional control valve 10 which is an operator for adjusting the heat exchange amount of the air cooling means 8, in addition to the rotation control of the fan filter unit 7. By controlling the outlet temperature of the air cooling means 8 according to the deviation from the set value based on the temperature measurement value of the supply air temperature sensor 13 that measures the outlet air temperature of 8, the circulating air of the entire large area can be obtained. It provides cold heat that can handle the heat generation load of the small areas 1 to 4.

On the other hand, since the control device 33 controls the inverter frequency of the fan motor of the fan filter unit 7, the blowing speed (wind speed) of each fan filter unit 7 can be known based on the frequency, and each fan filter unit has a flat area. The average wind speed can be found by adding up the values multiplied by and dividing by the total flat area again. As a result, the average value of the wind speeds blown into the small areas 1 to 4 in the large area 14 is obtained. For example, when the average value of the wind speeds of the large area 14 is 0.34 m / s at the beginning of a certain unit time. In addition, although the average value of the minimum wind speed for achieving the cleanliness of the large area 14 actually required is 0.30 m / s (target value), it is blowing more than that. The circulating air volume is excessive, and the fan carrying force of the fan filter unit is excessive, which is contrary to energy saving. To lower the average wind speed of the large area 14 while keeping the respective temperatures in the small areas 1 to 4 of the large area 14 at the set value (for example, SP = 23 ° C.), the circulating air If a temperature difference of around the air cooling means 8 is taken, that is, if the proportional control valve 10 is opened and cold heat is applied, the air volume control of each fan filter unit of the indoor small area temperature sensor 12 is controlled independently, which can be realized. Is. During a certain unit time, the temperature set value of the supply air temperature sensor 13 that controls the PID of the proportional control valve 10 is gradually changed to the lower side (for example, a gradient of 0.5 ° C./3 minutes). When the average value of the wind speed in the large area 14 reaches 0.30 m / s, the change in the temperature set value of the air supply temperature sensor 13 is stopped.
By doing so, it is possible to appropriately control the air volume of the fan filter unit 7 while keeping the indoor temperature of each of the small areas 1 to 4 uniform at 23 ° C.
As a result, the amount of air sent to the large area 14 can be reduced, and energy can be saved.

In the above embodiment, the average value (0.34 m / s) of the wind speed of the air blown into each group is obtained, and the average value (0.34 m / s) of the wind speed is 0.30 m / s, which is the minimum wind speed that can maintain the cleanliness. When the average wind speed reaches 0.30 m / s while operating the proportional control valve 10 to the open side by gradually lowering the set value of the air supply temperature sensor 13 so as to be s (provisional). Although the change in the set value was stopped, the set value of the supply air temperature sensor 13 was lowered in advance by controlling the wind speed of the air blown into each of the small areas 1 to 4 to 0.30 m / s in advance using Equation 2. Then, the proportional control valve 10 may be opened and closed so that the average wind speed of the large area 14 becomes 0.30 m / s (provisional) faster as a result.

K Building 1 Clean room 2 Ceiling 3 Side wall 4 Floor 5 Ceiling plenum chamber 6 Underfloor chamber 7 Fan filter unit (FFU)
8 Air cooling means 9 Piping 10 Proportional control valve 11 Retan shaft 12 Indoor small area temperature sensor 13 Supply air temperature sensor 14 Large area 20 Production equipment 31 Radio temperature sensor master unit 33 Control device

Claims (5)

A clean room (1) in which a ceiling plenum chamber (5) and a production device (20) into which air from the ceiling plenum chamber (5) flows in are arranged, and an underfloor chamber (1) in which air from the clean room (1) flows in. A clean room air-conditioning system comprising 6) and, in which air discharged from the underfloor chamber (6) is returned to the ceiling plenum chamber (5) via a retan shaft (11).
Clean air provided on the ceiling (2) of the clean room (1) is supplied to the clean room (1), and air is returned from the underfloor chamber (6) to the ceiling plenum chamber (5) via the retan shaft (11). A fan filter unit (7) that gives transport power to the air,
An air cooling means (8) that is provided at a position where air discharged from the underfloor chamber (6) and returned to the retan shaft (11) can pass and cools the air returned to the ceiling plenum chamber (5).
A small area is set in which the direction in which the ceiling plenum chamber (5) of the air blown into the clean room (1) travels is the vertical direction and the clean room (1) is divided in the vertical direction. A small indoor area temperature sensor (12) that measures the temperature,
An air supply temperature sensor (13) that measures the outlet air temperature of the air cooling means (8) in a one-to-one correspondence with the operator that adjusts the heat exchange amount of the air cooling means (8).
Of each small area divided in the vertical direction, the ceiling (2) of the corresponding small area is based on the measured value measured for each of the indoor small area temperature sensors (12) that measure the indoor temperature in each small area. The outlet temperature of the air cooling means (8) is set as a set value based on the temperature measurement value of the air supply temperature sensor (13) while controlling the blown air velocity of the group of the fan filter unit (7) provided in the above. A clean room air-conditioning system including a control device (33) that controls according to the deviation of the temperature. The control device (33) is a fan provided on the ceiling (2) of the corresponding small area based on the measured value obtained by measuring the indoor temperature in each small area with each of the indoor small area temperature sensors (12). Using the fan motor inverter as an operator, the frequency is output as a signal of the blown wind speed to the group of the filter unit (7), and the blown wind speeds of all the small areas are multiplied by the area of each small area and added up. The supply air temperature is adjusted by separately calculating the average blown wind speed and separately controlling the controller that adjusts the heat exchange amount of the air cooling means (8) so that the average blown wind speed value becomes the target average wind speed. The clean room air conditioning system according to claim 1, wherein the clean room air conditioning system is variably controlled. The indoor small area temperature sensor (12) can transmit a measured value signal wirelessly, and has a receiving master unit on the ceiling side.
The clean room air conditioning system according to claim 1 or 2, wherein the air supply temperature sensor (13) transmits a measurement signal by wire. The clean room air conditioning system according to claim 2, wherein the calculation of the average value of the wind speed is performed by the following formula.

The clean room air conditioning system according to claim 2, wherein the calculation of the average value of the wind speed is performed by the following formula.

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