Air conditioner temperature and humidity independent control system and method based on two-stage coil pipe chilled water

Abstract

The invention relates to an air conditioner temperature and humidity independent control system and method based on two-stage coil chilled water. On the basis of the existing chip plant temperature and humidity independent control based on a fresh air processing unit, a return air drying and cooling coil and a fan filtering unit, low-temperature chilled water outlet of a water chilling unit firstly passes through a fresh air re-cooling coil; return water obtained after the temperature of the fresh air re-cooling coil pipe rises serves as water supply of the fresh air pre-cooling coil pipe and the return air cooling dry coil pipe, so that two-stage coil pipe chilled water is formed, and the return water of the fresh air pre-cooling coil pipe and the return water of the return air cooling dry coil pipe are mixed and then serve as chilled water return water of the water chilling unit. By increasing the return water temperature of the water chilling unit, the average evaporation temperature of an evaporator of the water chilling unit is increased. A bypass is arranged between an inlet and an outlet of the return air cooling dry coil, and the air temperature in the plant is controlled by adjusting the bypass flow through an electric two-way adjusting valve and a PID controller. Compared with the prior art, the invention has the advantages of high unit energy efficiency ratio, low refrigeration energy consumption, simplified system and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to an independent temperature and humidity control system and method for air conditioning based on two-stage coil chilled water. Background Art

[0002] As an important part of computer science, display screens and mobile phone industries, semiconductor chip technology has a huge market and a large demand, and the number of clean factories used to produce chips has also increased rapidly. Due to the limitations of chip production and manufacturing processes, there are strict requirements for the temperature, humidity and cleanliness in the factory. For example, the temperature is often required to be controlled at ±0.5℃, the humidity is controlled at ±5%, and the indoor cleanliness requirements are generally high, which puts forward higher requirements on the air conditioning system in the factory. The current independent temperature and humidity control air conditioning system of chip factories is generally composed of a fresh air handling unit (MAU), a return air cooling dry coil (DCC) and a fan filter unit (FFU), thereby realizing fresh air processing, return air cooling and high-efficiency filtration respectively, but due to the large amount of air processed, the energy consumption level of such systems is very high. In the system, due to the freezing and dehumidification requirements of the fresh air, the outlet water temperature of the chiller is often low, but the DCC and fresh air pre-cooling coils require a higher chilled water temperature. Currently, medium-temperature chilled water is often obtained through heat exchange with low-temperature chilled water, which results in a lower operating evaporation temperature of the chiller, resulting in a lower energy efficiency ratio (COP) of the chiller (hereinafter referred to as a single chiller system). Some studies have shown that by adding a separate medium-temperature chiller to produce medium-temperature chilled water for DCC and fresh air pre-cooling, and a low-temperature chiller to produce low-temperature chilled water for the fresh air re-cooling coil, but this will lead to system complexity, increased initial investment and reduced efficiency of the low-temperature chiller (hereinafter referred to as a dual chiller system). Summary of the invention

[0003] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide an independent air-conditioning temperature and humidity control system and method based on two-stage coil chilled water with high COP of chiller unit, low system energy consumption, low system complexity and precise control.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] According to one aspect of the present invention, an air conditioning temperature and humidity independent control system based on two-stage coil chilled water is provided, comprising a clean workshop, a fresh air treatment unit, a fan filter unit and a return air dry cooling coil, the fan filter unit and the return air dry cooling coil are connected to the clean workshop, the fresh air treatment unit is connected to the fan filter unit, the fresh air treatment unit comprises a chiller, a fresh air pre-cooling coil and a fresh air re-cooling coil, the water outlet end of the chiller is connected to the water inlet end of the fresh air re-cooling coil, the water outlet end of the fresh air re-cooling coil is connected to the water inlet end of the fresh air pre-cooling coil and the water inlet end of the return air dry cooling coil, and the water outlet end of the fresh air pre-cooling coil and the water outlet end of the return air dry cooling coil are connected to the water inlet end of the chiller;

[0006] A bypass passage is provided between the water inlet and outlet of the return air dry cooling coil, an electric two-way regulating valve is provided on the bypass passage, an indoor temperature sensor is provided in the clean workshop, and the electric two-way regulating valve is connected to the indoor temperature sensor through a PID controller.

[0007] Furthermore, the fresh air processing unit also includes a fresh air reheat coil and a heat pump, the water outlet of the heat pump is connected to the water inlet of the fresh air reheat coil, and the water outlet of the fresh air reheat coil is connected to the water inlet of the heat pump.

[0008] Furthermore, a hot water pump is provided at the water outlet of the heat pump to drive the hot water generated by the heat pump to complete the circulation.

[0009] Furthermore, a chilled water pump is provided at the water outlet of the chiller to drive the chilled water generated by the chiller to complete the circulation.

[0010] Furthermore, the fresh air processing unit also includes a primary filter, a fresh air humidifier, a fresh air fan, a medium efficiency filter and a high efficiency filter. The primary filter is located at the air inlet end of the fresh air processing unit, and the high efficiency filter is located at the air outlet end of the fresh air processing unit.

[0011] Furthermore, the fresh air treatment unit drives the outside fresh air to complete the circulation through the fresh air fan. The outside fresh air enters the primary filter of the fresh air treatment unit from the air inlet end, and passes through the fresh air pre-cooling coil, fresh air re-cooling coil, fresh air reheating coil, fresh air humidifier, fresh air fan, medium efficiency filter and high efficiency filter in turn, and leaves the fresh air treatment unit from the air outlet end.

[0012] Furthermore, a technical interlayer is provided outside the clean workshop, the fresh air treatment unit is connected with the technical interlayer through an air outlet, and the technical interlayer is connected with the clean workshop through a fan filter unit.

[0013] Furthermore, an overhead floor is provided at the bottom of the clean workshop, and the technical mezzanine is connected to the clean workshop through the overhead floor; the return air cooling dry coil is located in the technical mezzanine and is connected to the clean workshop through the overhead floor.

[0014] Furthermore, an exhaust vent is provided under the elevated floor slab, and the technical mezzanine is connected to the outside world through the exhaust vent.

[0015] According to another aspect of the present invention, there is provided an air conditioning temperature and humidity independent control method based on an air conditioning temperature and humidity independent control system based on a two-stage coil chilled water, comprising the following steps:

[0016] Set the air temperature setting value in the clean room according to the process requirements;

[0017] According to local meteorological conditions, the total chilled water supply flow of the chiller and the water flow of the fresh air pre-cooling coil are adjusted through the chilled water pump, and the water supply flow of the heat pump is adjusted through the hot water pump;

[0018] Start the fresh air fan, so that the outside fresh air enters the technical mezzanine through the fresh air treatment unit, mixes with the return air in the technical mezzanine, enters the clean room through the fan filter unit, enters the technical mezzanine through the overhead floor, part of it enters the outside through the exhaust port, and part of it passes through the return air cooling dry coil to become return air and mix with the outside fresh air;

[0019] The temperature information in the clean room is obtained through the indoor temperature sensor and transmitted to the PID controller. The PID controller performs PID calculation according to the temperature information and the air temperature setting value and outputs a control signal. The control signal acts on the electric two-way regulating valve to adjust the valve opening and adjust the chilled water flow entering the return air cooling dry coil.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The fresh air processing unit of the present invention includes a chiller, a fresh air pre-cooling coil and a fresh air re-cooling coil. On the basis of the existing independent temperature and humidity control system of the chip plant, the pipeline layout of the chilled water is modified, and the flow line of the chilled water is optimized, so that the low-temperature chilled water outlet of the chiller first passes through the fresh air re-cooling coil, and the return water after the temperature of the fresh air re-cooling coil is increased is used as the water supply for the fresh air pre-cooling coil and the return air cooling dry coil, thereby forming a two-stage coil chilled water, and the return water of the fresh air pre-cooling coil and the return air cooling dry coil are mixed as the chilled water return water of the chiller. By increasing the return water temperature of the chiller, the average evaporation temperature of the chiller evaporator is increased, thereby improving the unit COP and reducing refrigeration energy consumption.

[0022] 2. The present invention improves the utilization efficiency of chilled water. One chiller can complete the task of producing chilled water. Compared with the dual-chiller system, the initial investment and system complexity of the system are significantly reduced, the total flow of chilled water is reduced, and the energy consumption of the water pump is reduced. At the same time, it can also avoid the low operating efficiency caused by the small flow of the low-temperature chiller in the dual-chiller system.

[0023] 3. The present invention realizes precise indoor temperature control by constructing a bypass passage with an electric two-way regulating valve between the inlet and outlet of the DCC, and controls the opening of the electric two-way regulating valve based on indoor temperature feedback and a PID controller; and realizes indoor relative humidity control by variable flow operation of chilled water.

[0024] 4. The control method involved in the present invention is designed with variable flow rate according to local meteorological conditions and fresh air dehumidification requirements. The fresh air precooling coil adopts fixed flow operation to achieve indoor humidity control. At the same time, the DDC flow rate is adjusted according to the indoor air temperature feedback, thereby achieving independent control of the indoor temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the system diagram of the independent temperature and humidity control system of air conditioning based on two-stage coil chilled water;

[0026] Figure 2 The temperature and humidity control process of the present invention;

[0027] Figure 3 The indoor temperature control of the present invention is compared with the simulation results of the single-cooling machine system and the dual-cooling machine system;

[0028] Figure 4 The indoor humidity control of the present invention is compared with the simulation results of the single chiller system and the dual chiller system;

[0029] Figure 5 The COP of the chiller of the present invention is compared with the simulation results of the single chiller system and the dual chiller system;

[0030] Figure 6 The energy consumption of the chiller of the present invention is compared with the simulation results of the single chiller system and the double chiller system;

[0031] Explanation of the reference numerals in the accompanying drawings: 1. Primary filter; 2. Fresh air pre-cooling coil; 3. Fresh air re-cooling coil; 4. Fresh air reheating coil; 5. Fresh air humidifier; 6. Fresh air fan; 7. Medium efficiency filter; 8. High efficiency filter; 9. Fan filter unit; 10. Clean workshop; 11. Indoor temperature sensor; 12. Overhead floor; 13. Return air cooling dry coil; 14. Exhaust vent; 15. PID controller; 16. Electric two-way regulating valve; 17. Heat pump; 18. Chiller; 19. Chilled water pump; 20. Hot water pump; 21. Fresh air treatment unit; 22. Technical mezzanine. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] like Figure 1 The system diagram of the air-conditioning temperature and humidity independent control system based on two-stage coil chilled water in this embodiment is shown, including a primary filter 1; a fresh air pre-cooling coil 2; a fresh air re-cooling coil 3; a fresh air reheating coil 4; a fresh air humidifier 5; a fresh air fan 6; a medium efficiency filter 7; a high efficiency filter 8; a fan filter unit 9; a clean workshop 10; an indoor temperature sensor 11; an overhead floor 12; a return air cooling dry coil 13; an exhaust port 14; a PID controller 15; an electric two-way regulating valve 16; a heat pump 17; a chiller 18; a chilled water pump 19; a hot water pump 19; a fresh air treatment unit 21; and a technical mezzanine 22.

[0034] The system is an air conditioning system deployed in a clean workshop 10 to achieve independent control of indoor temperature and humidity and cleanliness control. The primary filter 1 is located at the entrance of the fresh air treatment unit 21, and is used to achieve primary filtration of the fresh air; the fresh air precooling coil 2 is located in the fresh air treatment unit 21, and is used for precooling the fresh air; the fresh air recooling coil 3 is located after the fresh air precooling coil 2, and is used for recooling the fresh air, and is used together with the precooling coil for cooling and dehumidifying the fresh air; the fresh air reheating coil 4 is located after the fresh air recooling coil 3 in the fresh air treatment unit 21, and is used to reheat the fresh air; the fresh air humidifier 5 is located after the fresh air reheating coil 4 in the fresh air treatment unit 21, and is used to humidify the fresh air in winter; the fresh air blower 6 is located in the fresh air treatment unit 21, and is used to drive the fresh air; the medium efficiency filter 7 is located in the fresh air treatment unit 21, and is used for medium efficiency filtration of the fresh air; the high efficiency filter 8 is located after the medium efficiency filter 7 in the fresh air treatment unit 21, and is used for high efficiency filtration of the fresh air.

[0035] In this embodiment, the fan filter unit 9 is located at the top of the clean room 10, and is used to drive and filter the mixed fresh air and indoor return air; the clean room 10 is used for chip production and other process flows; the indoor temperature sensor 11 is located in the clean room 10, and is used to collect indoor temperature signals in real time; the overhead floor 12 is located on the floor of the chip factory, and is used for return air; the return air cooling dry coil 13 is located below the overhead floor 12, and is used to perform dry condition cooling on the return air; the exhaust outlet 14 is located below the overhead floor 12, and is used for exhaust.

[0036] In this embodiment, the PID controller 15 inputs the difference between the real-time indoor temperature and the set value, and uses the PID operation to output a control signal to the electric two-way regulating valve 16; the electric two-way regulating valve 16 is located in the bypass passage, and is used to receive the control signal output by the PID controller 15 and adjust the opening accordingly, thereby adjusting the flow of the bypass passage, and further adjusting the flow of chilled water entering the return air cooling dry coil 13, thereby achieving control of the indoor temperature; the heat pump 17 is used to produce hot water required for the fresh air reheat coil 4.

[0037] In this embodiment, the chiller 18 is used to produce the chilled water required for the fresh air re-cooling coil 3, the fresh air pre-cooling coil 2 and the return air cooling dry coil 13; the chilled water pump 19 is located after the water outlet of the chiller 18 and is used to drive the chilled water; the hot water pump 19 is located after the water outlet of the heat pump 17 and is used to drive the hot water; the fresh air treatment unit 21 is used for the temperature, humidity and cleanliness treatment of the fresh air; the technical mezzanine 22 is located outside the clean workshop 10 and is used for return air treatment and fresh air return mixing.

[0038] When in use, in the operating state, the operating personnel first set the air temperature set value in the clean room 10 according to the process requirements, and then turn on the power equipment such as the chiller 18, the heat pump 17, the water pump and the fan, and adjust the total chilled water supply flow of the chiller 18 and the water flow of the fresh air pre-cooling coil 2 according to the local meteorological conditions, and adjust the mechanical dew point temperature of the air after cooling and dehumidification so that the indoor air humidity distribution is within a reasonable range. At the same time, adjust the water supply flow of the heat pump 17, and adjust the temperature of the fresh air after reheating to reach the allowable temperature of the fresh air supply.

[0039] During operation, after the chilled water (usually 5-6°C) flows out of the chiller 18, it first passes through the fresh air re-cooling coil 3, and the temperature reaches 9-10°C after heat exchange. Part of the water flows to the fresh air pre-cooling coil 2, and is used together with the fresh air re-cooling coil 3 for cooling and dehumidifying the fresh air, and the other part flows to the return air cooling dry coil 13 for dry condition cooling of indoor return air. The return water of the return air cooling dry coil 13 and the return water of the fresh air pre-cooling coil 2 are mixed and then flow back to the chiller 18. A bypass passage and an electric two-way regulating valve 16 are arranged between the chilled water inlet and outlet of the return air cooling dry coil 13. During use, the outdoor fresh air is driven by the fresh air fan 6 and passes through the fresh air pre-cooling coil 2 and the fresh air re-cooling coil 3 in sequence for cooling and dehumidification. The fresh air is then heated to a suitable temperature by the fresh air reheating coil 4 and sent to the technical interlayer 22 after filtering. At the same time, the indoor return air flows into the technical interlayer 22 through the overhead floor 12, part of which is discharged through the exhaust port 14, and part of which is cooled in dry conditions by the return air cooling dry coil 13 and then mixed with the fresh air, filtered by the fan filter unit 9 and sent indoors.

[0040] In particular, the indoor temperature sensor 11 collects the indoor air temperature in real time and makes a difference with the set value. The difference signal is input into the PID controller 15, and the control signal is output after PID operation. The control signal acts on the electric two-way regulating valve 16 to adjust the valve opening, thereby adjusting the flow of chilled water entering the return air cooling dry coil 13, and further adjusting the return air cooling heat exchange in the return air cooling dry coil 13, thereby realizing the control of the indoor temperature.

[0041] The present embodiment provides a high-efficiency temperature and humidity independently controlled air-conditioning system based on two-stage coil chilled water. The supply and return water temperature difference of the chilled water can be increased by means of a two-stage coil. The return water temperature of the chilled water can be increased while the outlet water temperature of the chiller 18 remains unchanged. This can increase the average evaporation temperature of the evaporator of the chiller 18, increase the COP of the unit, and reduce energy consumption. At the same time, indoor temperature control can be achieved by adjusting the flow of the return air cooling dry coil 13 through a linear two-way regulating valve, a PID controller 15, and an indoor temperature sensor 11.

[0042] Figure 2 The process of realizing independent control of temperature and humidity of the present invention is demonstrated. First, the total flow of the chiller 18 and the total flow of the fresh air re-cooling coil 3 are adjusted, and the chilled water flow of the fresh air pre-cooling coil 2 is adjusted at the same time, so that the dew point temperature of the fresh air after passing through the fresh air re-cooling coil 3 meets the design requirements, and independent control of indoor humidity is realized; then, the return air cooling dry coil 13DDC flow is adjusted according to the indoor air temperature feedback through the PID controller 15 and the electric two-way regulating valve 16, so as to realize independent control of indoor temperature.

[0043] Figure 3 and Figure 4 The indoor temperature and humidity control of the present invention is compared with the simulation results of a single chiller system and a dual chiller system. It can be seen that the present invention can achieve independent control of indoor temperature and humidity under the input of actual meteorological parameters, wherein the fluctuation ranges of temperature and humidity are within a reasonable range, which is not much different from the single chiller system and the dual chiller system.

[0044] Figure 5 and Figure 6 The COP and energy consumption of the chiller 18 of the present invention are compared with the simulation results of the single chiller system and the dual chiller system. It can be seen that since the average evaporating temperature of the chiller 18 is increased, the COP of the chiller 18 is significantly higher under the present invention. Therefore, the refrigeration energy consumption can achieve 9% and 7% energy savings compared with the single chiller system and the dual chiller system.

[0045] The low-temperature chilled water supply (generally 5-6°C) of the chiller 18 is first supplied to the fresh air re-cooling coil 3 in the MAU for fresh air cooling and dehumidification. After heat exchange with the outdoor fresh air, the temperature rises to 9-10°C. The chilled water at this temperature meets the required temperature of the fresh air pre-cooling coil 2 in the DCC and MAU. Therefore, the outlet water of the MAU fresh air re-cooling coil 3 is supplied to the fresh air pre-cooling coil 2 in the DCC and MAU respectively through the water distributor. After heat exchange, the temperature is further increased to 14-15°C. The outlet water of the two is mixed in the water collector and supplied to the chiller 18. Through this setting, the return water temperature of the chilled water is further increased from 9-10°C to 14-15°C, thereby increasing the average evaporation temperature of the evaporator of the chiller 18. According to the basic principle of the reverse Carnot cycle, the COP of the chiller 18 can be effectively improved.

[0046] In terms of indoor temperature and humidity control, the total flow of chilled water is designed to be variable according to local meteorological conditions and fresh air dehumidification requirements, and the fresh air precooling coil 2 is operated at a constant flow rate to achieve indoor humidity control. A bypass is set between the chilled water inlet and outlet of the DCC, and an electric two-way regulating valve 16 is set on the bypass. The real-time temperature in the plant is obtained by a temperature sensor, and the electric two-way regulating valve 16 is feedback-regulated based on the PID controller 15, thereby further adjusting the chilled water flow entering the DCC. The temperature in the clean room 10 is controlled.

[0047] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An air conditioning temperature and humidity independent control system based on two-stage coil chilled water, comprising a clean room (10), a fresh air treatment unit (21), a fan filter unit (9) and a return air dry cooling coil (13), wherein the fan filter unit (9) and the return air dry cooling coil (13) are connected to the clean room (10), and the fresh air treatment unit (21) is connected to the fan filter unit (9), characterized in that: The fresh air processing unit (21) comprises a chiller (18), a fresh air precooling coil (2) and a fresh air recooling coil (3); the water outlet of the chiller (18) is connected to the water inlet of the fresh air recooling coil (3); the water outlet of the fresh air recooling coil (3) is connected to the water inlet of the fresh air precooling coil (2) and the water inlet of the return air dry cooling coil (13); the water outlet of the fresh air precooling coil (2) and the water outlet of the return air dry cooling coil (13) are connected to the water inlet of the chiller (18); A bypass passage is provided between the water inlet and the water outlet of the return air dry cooling coil (13), and an electric two-way regulating valve (16) is provided on the bypass passage. An indoor temperature sensor (11) is provided in the clean workshop (10), and the electric two-way regulating valve (16) is connected to the indoor temperature sensor (11) via a PID controller (15).

2. The air conditioning temperature and humidity independent control system based on two-stage coil chilled water according to claim 1 is characterized in that: The fresh air processing unit (21) further comprises a fresh air reheat coil (4) and a heat pump (17), wherein the water outlet of the heat pump (17) is connected to the water inlet of the fresh air reheat coil (4), and the water outlet of the fresh air reheat coil (4) is connected to the water inlet of the heat pump (17).

3. The air conditioning temperature and humidity independent control system based on two-stage coil chilled water according to claim 2 is characterized in that: A hot water pump (20) is provided at the water outlet of the heat pump (17) for driving the hot water generated by the heat pump (17) to complete the circulation.

4. The air conditioning temperature and humidity independent control system based on two-stage coil chilled water according to claim 1 is characterized in that: A chilled water pump (19) is provided at the water outlet of the chiller (18) for driving the chilled water generated by the chiller (18) to complete the circulation.

5. The air conditioning temperature and humidity independent control system based on two-stage coil chilled water according to claim 1, characterized in that: The fresh air processing unit (21) further comprises a primary filter (1), a fresh air humidifier (5), a fresh air blower (6), a medium efficiency filter (7) and a high efficiency filter (8); the primary filter (1) is located at the air inlet end of the fresh air processing unit (21), and the high efficiency filter (8) is located at the air outlet end of the fresh air processing unit (21).

6. The air conditioning temperature and humidity independent control system based on two-stage coil chilled water according to claim 5, characterized in that: The fresh air processing unit (21) drives the outside fresh air to complete the circulation through the fresh air fan (6). The outside fresh air enters the primary filter (1) of the fresh air processing unit (21) from the air inlet end, passes through the fresh air pre-cooling coil (2), the fresh air re-cooling coil (3), the fresh air reheating coil (4), the fresh air humidifier (5), the fresh air fan (6), the medium efficiency filter (7) and the high efficiency filter (8) in sequence, and leaves the fresh air processing unit (21) from the air outlet end.

7. The air conditioning temperature and humidity independent control system based on two-stage coil chilled water according to claim 6, characterized in that: A technical interlayer (22) is provided outside the clean workshop (10); the fresh air processing unit (21) is connected to the technical interlayer (22) via an air outlet; and the technical interlayer (22) is connected to the clean workshop (10) via a fan filter unit (9).

8. The air conditioning temperature and humidity independent control system based on two-stage coil chilled water according to claim 7, characterized in that: An overhead floor (12) is provided at the bottom of the clean workshop (10), and the technical mezzanine (22) is connected to the clean workshop (10) via the overhead floor (12); the return air cooling dry coil (13) is located in the technical mezzanine (22) and is connected to the clean workshop (10) via the overhead floor (12).

9. The air conditioning temperature and humidity independent control system based on two-stage coil chilled water according to claim 8, characterized in that: An exhaust port (14) is provided below the overhead floor (12), and the technical interlayer (22) is connected to the outside world through the exhaust port (14).

10. An independent air conditioning temperature and humidity control method based on the two-stage coil chilled water independent air conditioning temperature and humidity control system according to any one of claims 1 to 9, characterized in that: The following steps are involved: Set the air temperature setting value in the clean room according to the process requirements; According to local meteorological conditions, the total flow rate of chilled water supply of the chiller (18) and the water flow rate of the fresh air precooling coil (2) are adjusted by means of a chilled water pump (19), and the water flow rate of the heat pump (17) is adjusted by means of a hot water pump (20); Start the fresh air fan (6), so that the outside fresh air enters the technical interlayer (22) through the fresh air processing unit (21), is mixed with the return air in the technical interlayer (22), enters the clean room (10) through the fan filter unit (9), enters the technical interlayer (22) through the overhead floor (12), a part of it enters the outside through the exhaust port (14), and a part of it passes through the return air cooling dry coil (13) to become the return air and mix with the outside fresh air; The temperature information in the clean room (10) is obtained through the indoor temperature sensor (11), and the temperature information is transmitted to the PID controller (15). The PID controller (15) performs PID calculation according to the temperature information and the air temperature setting value and outputs a control signal. The control signal acts on the electric two-way regulating valve (16) to adjust the valve opening and adjust the flow of chilled water entering the return air cooling dry coil (13).

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