ISO 14644-1 clean room is a large energy consumer, this is because of the air cleanliness level, pressure difference, temperature and relative humidity required to maintain a clean production environment; to prevent cross-contamination of pollution, clean room should be based on the production process of the product. The whole room or local exhaust device required to eliminate dust, heat, organic solvents, etc. generated in the production process, and at the same time, it is necessary to send the corresponding or necessary outdoor fresh air into the clean room; according to different air cleanliness The requirements of the level require the necessary number of air changes and air supply. According to survey statistics, the power consumption of the clean air-conditioning system and its refrigerator in the clean workshop of a large-scale integrated circuit manufacturing factory accounts for about 50% of the total power consumption of the factory.
As mentioned above, the energy consumption of ISO 14644-1 clean room is very large. If the clean room is carefully designed and planned, it is possible to save energy and reduce energy consumption, and the potential capacity of energy saving is not small.
For the problem of energy saving in the operation of clean room and purification air conditioning system, there are the following solutions:
1. Process layout in ISO 14644-1 clean workshop
It is a feasible measure to reduce energy consumption and save energy by using clean rooms, clean workbenches, laminar flow hoods, clean tunnels, and micro-environments as much as possible to reduce the area of high-level clean rooms. Studies have shown that compared with traditional production environments, the investment in micro-environment clean workshops can be saved by 40%, and the cost of air transportation alone can be saved by 70%.
2. When designing building planes and facades, efforts should be made to implement energy-saving requirements
Whether the door and window design of ISO 14644-1 clean workshop is appropriate or not is an important issue to reduce the energy consumption of clean workshop buildings. The first is to control the window-to-wall ratio, and minimize the window area on the outer wall according to the characteristics of the clean room. The second is the air-tightness requirements of the door and window structure and the selection of high-quality and reliable materials to ensure the thermal insulation (cold) effect of the doors and windows and reduce cold air. Penetration to prevent the occurrence of the "cold bridge" phenomenon.
3. Technical measures to reduce the heat (cold) load of the clean room
(1) According to the production process requirements of the product, determine the appropriate clean room air cleanliness level, temperature and relative humidity parameters. On the premise of meeting the production process, from the perspective of energy saving, determine the air cleanliness according to the different requirements of different processes and rooms. The parameters of degree level, temperature, and relative humidity may be as low as possible.
(2) Under the close cooperation of the product production process provider, accurately determine the exhaust air volume of the room or process or production equipment that needs to be equipped with an exhaust device in the clean room. This is due to the increase in the exhaust air volume in the clean room, which means The supplemental fresh air volume of the purifying air conditioning system is increased. In the plant design, it sometimes occurs that the fresh air volume of the purification air conditioning system is larger than the specified fresh air demand due to the increase of the exhaust air volume, thereby increasing the designed heat (cooling) load. Therefore, it is necessary to accurately determine whether the exhaust air volume in the clean room is reduced. One of the important technical measures of energy consumption.
4. Technical measures to reduce the air supply volume of the purification air conditioning system and reduce the resistance of the system
(1) According to the different air cleanliness levels and different working hours and shifts required by the production process, the purification air-conditioning system is reasonably divided. However, when formulating the plan, serious consideration should be given to the technical measures necessary to reduce the length of the pipeline and reduce the resistance of the air duct, so as to reduce the electricity consumption without increasing the construction cost.
(2) Reasonably organize the setting of various air filters in the purification air conditioning system, and control the air supply volume for the fresh air concentration of the purification air conditioning system of the larger clean workshop.
(3) The design of ISO 14644-1 purification air-conditioning system should make reasonable use of return air. When the product production process does not produce harmful substances or cross contamination, the purification air conditioning system should use the return air as much as possible in order to reduce energy consumption under the condition of ensuring the amount of fresh air and maintaining the pressure difference specified in the clean room. For a one-way flow clean room with a large number of air changes, when the air conditioner room is far away from the one-way flow clean room, a part of the air can be directly recycled without returning to the machine room, which can reduce energy consumption.
5. Reasonably carry out the air duct design of the purification air conditioning system
When laying out the air duct, the length of the air duct should be shortened as much as possible, the setting of unnecessary bends and accessories should be reduced, the shape of the air duct should be simplified, and efforts should be made to reduce the resistance of the air duct system to reduce energy consumption.
6. Using variable flow to control air volume and water volume
(1) Control and adjust the air supply volume according to the detected number of dust particles in the clean room, or the room pressure value. Adopt technical measures to effectively control the non-working production process or the low air supply in the room.
(2) According to the characteristics of the production process, set up the exhaust device to detect and control the room or equipment, control the exhaust air volume or start and stop the exhaust fan or exhaust valve as needed. Avoid opening the exhaust fan or exhaust valve when the room or equipment is not in production, consuming electricity and increasing unnecessary air supply.
(3) Fans and water pumps are reasonably equipped with frequency conversion units, and the speed of fans and water pumps can be changed according to the amount of air supply and water supply to reduce power consumption.
(4) The air-conditioning unit of the ISO 14644-1 purification air-conditioning system adopts frequency conversion control of the amount of cold water, hot water or steam.