JP4896197B2 - Precision temperature control air conditioner - Google Patents

Description

  The present invention relates to a precision temperature control air conditioner for maintaining a constant state of air in a chamber in which various precision processing devices are installed inside used in the field of manufacturing semiconductors and liquid crystal panels. In particular, the present invention relates to an air conditioner that can save space and energy.

  Air conditioners that precisely control the temperature and humidity of the air by circulating the air in the chamber via a heat exchanger are installed in the chamber where the processing equipment and measuring equipment in the semiconductor and liquid crystal panel manufacturing processes are installed. is set up.

As shown in FIG. 1, the air temperature control system using such an air conditioner generally takes out air in a chamber in which a manufacturing apparatus or the like is installed as return air and introduces it into a heat exchanger. In this system, the temperature is adjusted by cooling with heat exchange with the refrigerant, and then returned to the chamber as feed air.
Specific examples of the air conditioner as described above include a direct expansion coil system as shown in FIG. 2 and a water coil system air conditioner as shown in FIG.

As shown in FIG. 2, the air conditioner employing the direct expansion coil system introduces “return air” extracted from the chamber into the heat exchanger ₁₀₁ through the air flow path a ₁₀₁ and performs heat exchange with the refrigerant. After that, it is extracted from the air flow path a ₁₀₂ , and if necessary, the temperature is further finely adjusted by the heating coil 105 and returned from the air flow path a ₁₀₃ to the chamber as “feed air”. Then, the refrigerant heat-exchanged with the return air extracted from the chamber by the heat exchanger ₁₀₁ is taken out as a low-pressure refrigerant gas to the refrigerant flow path L ₁₀₁ and sent to the refrigerant compressor 102 to be compressed refrigerant gas, and the refrigerant flow path L ₁₀₂ and the low-temperature high-pressure refrigerant liquid condensed and liquefied by sending the refrigerant condenser 103 from removed through the refrigerant flow path L _{10 3,} sent to the expansion valve 104, the heat exchanger 10 as an expansion refrigerant liquid And a "refrigerant circulation channel" hereinafter, and supplies the. (Patent Literature 1, Patent Literature 2, Patent Literature 3).

  The direct expansion coil type air conditioner has an advantage that it has excellent heat exchange performance and can save space compared to a water coil type air conditioner. However, as shown in FIG. 2, the drain flow path D shows that the refrigerant temperature in the cooling coil of the heat exchanger 101 has returned to be below the dew point of the moisture in the air, and dew is condensed around the cooling coil to dehumidify the air. Thus, there are a problem that the “feed air” returned to the chamber is in a dry state where static electricity is easily generated, a problem that the cooling coil in the heat exchanger 101 is corroded by condensation, and the like.

As shown in FIG. 3, the water coil type air conditioner sends “return air” extracted from the chamber to the heat exchanger _{201 a} from the air flow path a ₂₀₁ and adjusts the temperature by heat exchange, and then, as necessary. Te, a further temperature at the heating coil 205 a of the air passage a ₂₀₂ finely adjusted, back into the chamber from the air flow path a ₂₀₃ as "feed air", and "chamber air circulation path" that, taken out from the chamber water refrigerant heat exchanger went back in the air and the heat exchanger 201a has, after removal by the pump P from the heat exchanger 201a is disposed on the refrigerant passage L ₂₀₁ as low-pressure water coolant, replace another refrigerant heat cooled, circulated through the heat exchanger 201b to circulate from the coolant passage L ₂₀₄ as cold water coolant to the heat exchanger 201a "water refrigerant circulation channel", the water coolant circulation path of water After heat exchange in medium and the heat exchanger 201b, is taken out to the refrigerant passage L ₂₀₂ as a low-pressure refrigerant from the heat exchanger 201b, it is compressed by the refrigerant compressor 202 and the compressed refrigerant gas, through the refrigerant passage L ₂₀₃ refrigerant sent to the condenser 20 3, the low-temperature high-pressure refrigerant liquid is cooled condensed, removed the refrigerant passage L ₂₀₅ sends the expansion valve 204, the heat exchanger from the refrigerant passage L ₂₀₆ as an expansion refrigerant liquid is expanded by the expansion valve 204 It has a “refrigerant circulation path” of circulating supply to the vessel 201b.

In this water coil type air conditioning system, the temperature of the water refrigerant flowing through the coil in the heat exchanger 201a is equal to or higher than the dew point temperature of water in the "return air" from the chamber (the temperature at which the relative humidity becomes 100%). This has the advantage that it is easy to keep the humidity of the “feed air” returned into the chamber constant.
However, apart from the “water refrigerant circuit”, it is necessary to install a refrigerant circuit of another system for cooling the water refrigerant with a heat exchanger. There are drawbacks in that the energy cost increases and the control system for the entire air conditioner becomes complicated.

JP 2007-212095 A JP 2009-14226 A JP 11-325507 A

  The present invention is an air conditioner having an expansion valve that is superior in heat exchange performance compared to a water coil type air conditioner and can save space, and the state of the refrigerant in the cooling coil of the heat exchanger It is possible to control the surface temperature of the cooling coil by adjusting automatically, and the state of the low-pressure refrigerant gas that exits the cooling coil of the heat exchanger and enters the compressor is the refrigerant gas state in which the compressor operates normally It is an object of the present invention to provide an energy-saving and space-saving air conditioner that can be automatically adjusted so that

  The present invention that can solve the above-mentioned problems is the first heat exchanger in the low-pressure refrigerant gas flow path that has been heat-exchanged from the first heat exchanger that performs heat exchange between the return air and the refrigerant to the compressor. In order to maintain the state of the refrigerant evaporating pressure adjusting valve capable of automatically adjusting the refrigerant evaporating pressure in the cooling coil and the state of the low-pressure refrigerant gas sent to the refrigerant gas compressor in a state where the compressor operates normally It is invention regarding the air conditioner characterized by having arrange | positioned the 2nd heat exchanger of this, and includes each following invention.

(1) An air circulation path that sends air in the precision device installation chamber to a first heat exchanger that performs heat exchange between the air and the refrigerant, cools the air to a target temperature higher than the dew point temperature of the air, and returns the air into the chamber;
The low-pressure refrigerant gas coming out of the first heat exchanger is compressed by a compressor, then condensed by a condenser to form a low-temperature high-pressure refrigerant liquid, and the low-temperature high-pressure refrigerant liquid is supplied from an expansion valve to the cooling coil of the first heat exchanger An air conditioner having a refrigerant circulation path to be sent to
The air circulation path is provided with a temperature sensor for air whose temperature is adjusted by the first heat exchanger,
In the refrigerant circuit, a first pressure sensor, a refrigerant evaporation pressure adjusting valve, and a second heat exchange are sequentially provided from the first heat exchanger side in the low-pressure refrigerant gas flow path between the first heat exchanger and the compressor. And a second pressure sensor are installed, and the compressed refrigerant flow path between the compressor and the condenser is branched from the compressed refrigerant flow path directly connected to the condenser from the compressor. A compressed refrigerant branch passage connected to the condenser via the second heat exchanger is installed,
The refrigerant evaporating pressure adjusting valve automatically controls the valve opening based on the measured value of the air temperature by the temperature sensor of the air circulation path and the measured value of the low-pressure refrigerant gas pressure by the first pressure sensor of the refrigerant circulation path. Is a valve that automatically adjusts the refrigerant evaporation pressure in the cooling coil of the first heat exchanger,
The second heat exchanger is a heat exchanger that heats the low-pressure refrigerant gas before entering the compressor by heat exchange with the high-temperature compressed refrigerant flowing through the compressed refrigerant branch passage, and is a precision temperature control air conditioner Machine.

(2) The precision temperature controlled air conditioner according to (1), wherein a heater for further finely adjusting the air temperature is installed in the air circulation path downstream of the first temperature sensor. .

(3) The second heat exchanger is a high-temperature compressed refrigerant that flows through a compressed refrigerant branch passage having a valve that automatically controls a supply amount of the high-temperature compressed refrigerant based on a measured value of the low-pressure refrigerant gas pressure by the second pressure sensor. The precision temperature control air conditioner according to item (1) or (2), characterized in that the heat exchanger adjusts the pressure of the refrigerant gas sent to the compressor by heat exchange.

(4) The condenser is provided with a third pressure sensor in a low-temperature high-pressure refrigerant liquid flow path from the condenser to the expander, and is condensed based on a measured value of the low-temperature high-pressure refrigerant liquid pressure by the third pressure sensor. The precision temperature control air conditioner according to any one of items (1) to (3), wherein the water cooling mechanism installed in the vessel is a condenser that is automatically controlled.

(5) Item (1) to (4), characterized in that a sight glass capable of visually observing the state of the low-temperature and high-pressure refrigerant liquid is disposed in the low-temperature and high-pressure refrigerant liquid flow path from the condenser to the expander. The precision temperature control air conditioner of any one of these.

  According to the precision device chamber air conditioner of the present invention, the state of the refrigerant gas in the cooling coil, which fluctuates due to the fluctuation of the load of the cooling coil of the heat exchanger, the temperature sensor installed in the air circulation path and the low-pressure refrigerant gas flow The temperature of the cooling coil is constantly measured by a pressure sensor installed on the road, and the refrigerant gas pressure in the cooling coil is adjusted by automatically controlling the opening of the refrigerant evaporation pressure adjustment valve based on both measured values. Can be adjusted in real time, and the pressure of the low-pressure refrigerant gas entering the compressor by the second heat exchanger in the low-pressure refrigerant gas flow path is constantly adjusted so that no liquid back or wet compression occurs. Is possible. Furthermore, since the high-temperature compressed gas flowing through the compressed refrigerant branch flow path is effectively used as the heating medium of the second heat exchanger, it is not necessary to secure a new medium circulation device space for the second heat exchanger, This air conditioner has achieved energy saving and space saving.

It is a figure which shows the basic aspect of a precision air conditioner. It is the schematic of the air conditioner which employ | adopted the general direct expansion coil system. It is the schematic of the air conditioner which employ | adopted the general water coil system. It is a figure explaining the air conditioner of this invention.

Hereinafter, the air conditioner of this invention is demonstrated in detail with reference to FIG.
In the precision temperature control air conditioner of the present invention, the “return air” extracted from the precision device chamber (not shown) to the “air flow path a1” is “expansion valve” in the “first heat exchanger 1”. 4 ”is cooled to a target temperature higher than the dew point temperature of the air by heat exchange with the expanded refrigerant supplied to the cooling coil of the“ first heat exchanger 1 ”, and the“ air flow sensor ”in which the“ temperature sensor T1 ”is installed An "air circulation path" circulated as "feed air" from the "air flow path a3" where the "temperature sensor T2" is installed through the "heater 5" from the "path a2" into the precision device chamber;
The heat-exchanged low-pressure refrigerant gas exiting from the cooling coil of the first heat exchanger 1 reaches the “compressor 2” through the “second heat exchanger 6” and is compressed into a high-temperature compressed refrigerant gas. Thereafter, the refrigerant is condensed in the “condenser 3” to form a low-temperature high-pressure refrigerant liquid, and the low-temperature high-pressure refrigerant liquid is sent to the expansion valve 4 through the “low-temperature high-pressure refrigerant liquid flow path L3”. It is an air conditioner having a “refrigerant circulation path” that is sent to the cooling coil of the first heat exchanger 1 via the path L4 ”.

In the air circulation path, the air extracted from the chamber to the air flow path a1, for example, return air whose temperature fluctuates in the range of 23 ° C. to 26 ° C. in the chamber, is cooled in the first heat exchanger 1 by the cooling coil. It is cooled by. The temperature of the cooled air is measured by the first temperature sensor T1 in the air flow path a2, and is sent to the air flow path a3 through the heater 5. The air passage a3 is installed a second temperature sensor T2, the heater 5 is controlled based on the second temperature sensor T 2 in the measured air temperature is installed, the temperature in the heater 5 as required to fine Air that has been adjusted and precisely adjusted to a target temperature ± 0.05 ° C. is returned to the chamber as feed air.

  In the refrigerant circuit, a low-pressure refrigerant gas pressure coming out of the cooling coil of the first heat exchanger 1 is added to a refrigerant gas passage L1a through which the heat-exchanged low-pressure refrigerant gas coming out of the cooling coil of the first heat exchanger 1 flows. A pressure sensor P1 to be measured, and a refrigerant evaporation pressure adjusting valve E1 whose opening degree is automatically controlled based on a temperature measurement value by the temperature sensor of the air flow path and a refrigerant gas pressure measurement value by the pressure sensor P1 are installed. Yes. The first feature of the air conditioner of the present invention is that it has the refrigerant evaporation pressure adjusting valve E1.

In the case of the refrigerant gas in the gas / liquid mixed state in the cooling coil of the first heat exchanger 1, since the pressure and the temperature are in a proportional relationship, the temperature of the cooling coil should be managed by controlling the pressure in the cooling coil. Is possible.
The refrigerant evaporating pressure adjusting valve E1 includes a measured value of the air temperature after heat exchange measured by the temperature sensor of the air flow path and the pressure of the low pressure refrigerant gas by the first pressure sensor P1 installed in the low pressure refrigerant flow path L1a. Is a valve whose opening degree is automatically controlled based on the measured value, and the refrigerant evaporative gas pressure in the cooling coil is controlled by the opening degree, thereby controlling the refrigerant gas temperature in the cooling coil. It has.

When the refrigerant evaporation pressure adjusting valve E1 detects that the measured value of the air temperature after the heat exchange by the temperature sensor of the air flow path is lower than the target temperature, the refrigerant evaporating pressure adjustment valve E1 is installed in the low pressure refrigerant flow path L1a. In relation to the measured value of the low-pressure refrigerant gas pressure by the pressure sensor P1, the refrigerant evaporating pressure in the cooling coil automatically operates in the “closed” direction so as to increase to a pressure having the refrigerant gas temperature as a target temperature.
Conversely, when it is detected that the measured value of the air temperature after heat exchange by the first temperature sensor T1 of the air flow path is higher than the target temperature, the refrigerant evaporation pressure adjustment valve E1 is moved to the “open” side. It automatically operates to lower the refrigerant pressure in the cooling coil, thereby adjusting the refrigerant gas temperature in the cooling coil to a target value.

  As described above, the air conditioner of the present invention has a low pressure refrigerant evaporating pressure adjusting valve E1 that quickly reacts to a change in refrigerant gas temperature in the cooling coil of the first heat exchanger 1 and adjusts the pressure in the cooling coil. By installing in the refrigerant flow path L1, it is an air conditioner which can control the 1st heat exchanger precisely and in real time.

The air conditioner of the present invention heats the low-pressure refrigerant gas, which is often in a gas / liquid mixed state, and sends it to the refrigerant compressor in a completely gasified state, so that the low-pressure refrigerant downstream from the refrigerant evaporation pressure adjustment valve E1. The second technical feature is that the second heat exchanger 6 is arranged in the gas flow path L1b.
In the second heat exchanger 6, the pressure state of the low-pressure refrigerant gas measured by the second pressure sensor P2 that measures the pressure of the low-pressure refrigerant gas entering the refrigerant compressor in the low-pressure refrigerant gas flow path L1c downstream thereof is the low pressure refrigerant gas. It operates automatically when it is necessary to turn the refrigerant gas into a heated gas.

  The low-pressure refrigerant gas in which the refrigerant liquid remains in the low-pressure refrigerant gas or the re-liquefaction of the refrigerant gas is in a low pressure state, and causes a failure of the compressor 2 as it is. When the pressure sensor P2 detects such a state of the low-pressure refrigerant gas, the high-temperature compression flowing through the compressed refrigerant branch flow path L2b branched from the compressed refrigerant flow path L2a from the refrigerant gas compressor 2 to the compressed refrigerant condenser 3 The heat exchanger 6 that uses the refrigerant is activated, and the low-pressure refrigerant gas is heated and completely gasified by heat exchange with the high-temperature compressed refrigerant flowing through the compressed refrigerant branch flow path L2b, and is introduced into the compressor 2.

The compressed refrigerant flow path L2a directly connected to the condenser 3 from the compressor 2 has a valve E2, and the compressed refrigerant branch flow path L2b connected to the condenser 3 via the second heat exchanger 6 is When the pressure value of the low-pressure refrigerant gas detected by the pressure sensor P2 decreases, the valve E3 of the compressed refrigerant branch flow path L2b is operated in the “open” direction. Then, the valve E3 of the compressed refrigerant flow path L2a operates in the “closed” direction to adjust the supply amount of the high-temperature compressed refrigerant gas to the second heat exchanger.
Conversely, when the pressure value of the low-pressure refrigerant gas detected by the pressure sensor P2 is an appropriate value, the valve E3 of the compressed refrigerant branch flow path L2b remains in the “closed” state, and the valve 2 of the compressed refrigerant flow path L2a In the “open” state, the entire amount of the high-temperature compressed refrigerant gas is directly sent to the condenser.

As described above, in the air conditioner of the present invention, the state of the refrigerant gas introduced into the refrigerant gas compressor 2 from the refrigerant gas flow paths L1b and L1c is always gasified by having the second heat exchanger. Therefore, the compressor does not break down due to wet compression or liquid compression, or the compressor does not stop to protect the device.
Further, since the medium for heating the low-pressure refrigerant gas in the second heat exchanger 6 is procured in the refrigerant circulation path in the air conditioner of the present invention, a circulation system for the heating medium to the second heat exchanger is newly provided. Little additional space is required for installation.

The compressed refrigerant from the compressed refrigerant flow path L2a and the compressed refrigerant branch flow path L2b is sent to the compressed refrigerant condenser 3. The compressed refrigerant condenser 3 has a water cooling mechanism 8 in which cooling is controlled by adjusting the amount of cooling water entering the condenser 3 from the cooling water supply port W1 and discharged from the cooling water discharge port W2 with a valve M. is doing.
In order to keep the temperature and pressure of the condensate constant, a “third pressure sensor P3” that measures the pressure of the refrigerant liquid is installed in the low-temperature high-pressure refrigerant liquid flow path L3 that exits from the compressed refrigerant condenser 3, and the third pressure The water cooling mechanism 8 is controlled so that the measurement pressure of the sensor P3 is always constant.

  The low-temperature high-pressure refrigerant liquid prepared in the condenser 3 is sent to the expansion valve 4 through the low-temperature high-pressure refrigerant liquid flow path L3. In the low-temperature high-pressure refrigerant liquid flow path L3, a receiver tank 9 that stores the low-temperature high-pressure refrigerant liquid flowing in the flow path and a “sight glass 10” that visually monitors the state of the cold / high-pressure refrigerant liquid can be installed.

The expansion valve 4 controls the amount of refrigerant liquid flowing into the cooling coil in response to the load fluctuation of the cooling coil. The expanded refrigerant liquid leaving the expansion valve 4 and flowing through the expanded refrigerant liquid flow path L4 is depressurized and evaporates and is in a gas / liquid mixed state because there is no heat transfer.
The expansion valve can employ temperature automatic expansion valve or the like.

  In the case of the precision temperature control air conditioner of the present invention, the cooling temperature in the cooling coil is set to a normal air conditioner (e.g. 15 ° C to 18 ° C). The refrigerant evaporating pressure in the cooling coil of the first heat exchanger 1 is controlled by automatically controlling the opening degree of the refrigerant evaporating pressure adjusting valve E1, but the expansion valve 4 is also expanded refrigerant according to the temperature state in the cooling coil. The supply amount is adjusted. Thus, although the state in the cooling coil is controlled by both the refrigerant evaporation pressure adjusting valve E1 and the expansion valve, the degree of contribution to the temperature stability accuracy of the heat-exchanged air varies depending on the state change in the cooling coil. The control operation of the refrigerant evaporating pressure in the cooling coil by the refrigerant evaporating pressure adjusting valve E1 having a faster response speed is greater.

  As described above, the precision temperature control air conditioner of the present invention uses the refrigerant evaporation pressure in the cooling coil of the first heat exchanger 1 in the cooling coil with a fast response speed installed in the same refrigerant gas flow path L1a. By adopting a system in which the refrigerant evaporation pressure adjustment valve E1 is operated to quickly control the refrigerant evaporation pressure in the cooling coil, the air temperature is adjusted quickly and accurately in units of 1 / 100C. It is what made it possible.

  As described above, the precision device chamber air conditioner according to the present invention employs the cooling coil internal environment control system in which the refrigerant evaporation pressure control valve E1 and the expansion valve 4 work together, thereby enabling extremely precise temperature control. In addition to making it possible to achieve this, it is possible to continuously operate the refrigerant gas compressor by efficiently using the high-temperature compressed refrigerant that can be procured in the refrigerant circulation system, achieving space and energy savings. Therefore, the basic technical concept adopted in the air conditioner of the present invention is applicable not only to the field of precision device chamber air conditioners but also to air conditioning systems in a wide range of industrial fields.

1: First heat exchanger 2: Refrigerant gas compressor 3: Compressed refrigerant condenser 4: Expansion valve 5: Heater (electric type)
6: Second heat exchanger 7: Accumulator (liquid separator)
8: Water cooling mechanism 9: Receiver tank (liquid receiver)
10: Sight glass T1: First temperature sensor T2: Second temperature sensors P1 to P3: Pressure sensor E1: Refrigerant evaporation pressure adjustment valve E2: Compressed refrigerant flow path valve E3: Compressed refrigerant branch flow path valves a1 to a2: Air flow paths L1a to L1c: Low-pressure refrigerant gas flow path L2a: Compressed refrigerant flow path L2b: Compressed refrigerant branch flow path L3: Low-temperature high-pressure refrigerant liquid flow path L4: Expanded refrigerant liquid flow path

Claims (5)

An air circulation path that sends the air in the precision device installation chamber to the first heat exchanger that performs heat exchange between the air and the refrigerant, cools the air to a target temperature higher than the dew point temperature of the air, and returns the air to the inside of the chamber;
The low-pressure refrigerant gas coming out of the first heat exchanger is compressed by a compressor, then condensed by a condenser to form a low-temperature high-pressure refrigerant liquid, and the low-temperature high-pressure refrigerant liquid is supplied from an expansion valve to the cooling coil of the first heat exchanger An air conditioner having a refrigerant circulation path to be sent to
The air circulation path is provided with a temperature sensor for air whose temperature is adjusted by the first heat exchanger,
In the refrigerant circuit, a first pressure sensor, a refrigerant evaporation pressure adjusting valve, and a second heat exchange are sequentially provided from the first heat exchanger side in the low-pressure refrigerant gas flow path between the first heat exchanger and the compressor. And a second pressure sensor are installed, and the compressed refrigerant flow path between the compressor and the condenser is branched from the compressed refrigerant flow path directly connected to the condenser from the compressor. A compressed refrigerant branch passage connected to the condenser via the second heat exchanger is installed,
The refrigerant evaporating pressure adjusting valve automatically controls the valve opening based on the measured value of the air temperature by the temperature sensor of the air circulation path and the measured value of the low-pressure refrigerant gas pressure by the first pressure sensor of the refrigerant circulation path. Is a valve that automatically adjusts the refrigerant evaporation pressure in the cooling coil of the first heat exchanger,
The second heat exchanger is a heat exchanger that heats the low-pressure refrigerant gas before entering the compressor by heat exchange with the high-temperature compressed refrigerant flowing through the compressed refrigerant branch passage, and is a precision temperature control air conditioner Machine.   2. The precision temperature control air conditioner according to claim 1, wherein a heater for further finely adjusting the air temperature is installed in the air circulation path downstream of the first temperature sensor.   The second heat exchanger heats the high-temperature compressed refrigerant flowing through the compressed refrigerant branch passage having a valve that automatically controls the supply amount of the high-temperature compressed refrigerant based on the measured value of the low-pressure refrigerant gas pressure by the second pressure sensor. The precision temperature control air conditioner according to claim 1 or 2, wherein the air conditioner is a heat exchanger that adjusts a refrigerant gas pressure sent to the compressor by exchange.   The condenser is provided with a third pressure sensor in the low-temperature and high-pressure refrigerant liquid flow path from the condenser to the expander, and installed in the condenser based on the measured value of the low-temperature and high-pressure refrigerant liquid pressure by the third pressure sensor. The precision temperature control air conditioner according to any one of claims 1 to 3, wherein the water cooling mechanism is a condenser that is automatically controlled.   The sight glass which can visually observe the state of low-temperature / high-pressure refrigerant liquid is disposed in the low-temperature / high-pressure refrigerant liquid flow path from the condenser to the expander. Precision temperature control air conditioner.

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