Main energy-saving measures for cleanroom air conditioning systems

2023-08-04

original

Marya

To reduce the energy consumption of a cleanroom, the planning and design of a cleanroom are very important links. Try to choose sites with low air pollution and low dust production to build factories; When arranging in the factory, the cleanroom should be located in a place with less pollution, paying attention to the orientation arrangement,and strengthening the setting of green belts.

1、Design with energy-saving concept

To reduce the energy consumption of a cleanroom, the planning and design of a cleanroom are very important links.
(1)Try to choose sites with low air pollution and low dust production to build factories; When arranging in the factory, the cleanroom should be located in a place with less pollution, paying attention to the orientation arrangement,and strengthening the setting of green belts.
(2)The layout of the cleanroom should minimize the area of the cleanroom or reduce the area of the cleanroom with strict cleanliness requirements; Processes and equipment that do not locate in cleanrooms should be located in non clean areas; Properly determine the air cleanliness level of various rooms, and cleanliness requirements should not be increased arbitrarily; Organize the flow of people, logistics, and arrange auxiliary housing; Cooperate with relevant parties to select the form and spatial layout of the cleanroom.
(3)Reasonably determine the structure and material selection of walls and ceilings, paying special attention to the determination of enclosure structures and the selection of building materials, as well as the structure and material selection of doors and windows; In the selection of facades and the determination of the number of doors and windows, attention should be paid to the characteristics of reducing heat transfer in the cleanroom, avoiding large windows and multiple windows to reduce cooling loss.

(4)Control the fresh air volume and exhaust air volume of the system. In the operation of the purification air conditioning system, the amount of fresh air largely determines the energy consumption of the system. When designing, human comfort factors are generally considered, and the upper limit of the reference value is taken. However, there are often not many operators in production, and the resulting energy consumption is often ignored. All exhaust air volume in the system is generally supplemented by fresh air, and the exhaust air volume should be adjusted according to the indoor working conditions. The exhaust air volume should be controlled within an appropriate range, which can meet the requirements of process conditions for exhaust air and reduce the amount of fresh air consumed by the system. It can reduce the cold and heat consumption of the purification air conditioning system for fresh air treatment. Fresh air should be treated in a centralized manner as much as possible, which can also consider applying groundwater precooling, dust removal, and humidification.
(5)Minimize system resistance in cleanroom pipeline design as much as possible. Reducing system resistance in pipeline design can also achieve the effect of reducing supply air power consumption. Try to avoid long-distance air supply, shorten the length of the air duct, and reduce the resistance of air duct components such as elbows and tees. On the premise of meeting the wind speed requirements, using low wind speed air supply and selecting an appropriate wind speed can reduce the resistance of the filter.
(6)Adopt secondary return air treatment. To reduce electrical energy consumption, try to use return air through sub filtration while avoiding cross contamination. The secondary return air not only meets the requirements of temperature, humidity, and cleanliness, but also greatly saves energy consumption of the air conditioning unit. The operating cost of the air conditioning unit can be saved by about 2/3. Adopting a secondary return air system can save equipment investment and reduce operating costs compared to a primary return air system.

(7)Adjust temperature and humidity according to different seasons. On the premise of meeting the production process, from the perspective of energy conservation, it is necessary to determine appropriate parameters such as cleanliness level, temperature, relative humidity, etc. for the cleanroom.
(8)Reduce the number of air change rate in the cleanroom. On the premise of ensuring the cleaning effect, reducing the air changes rate and air supply volume is one of the important means of energy conservation. Air changes rate is closely related to production process, equipment degree, layout, size and shape of cleanroom, and personnel density.
(9)Reduce the lighting intensity appropriately. Cleanroom lighting should be based on meeting the physiological and psychological requirements of workers. For high illumination operating points, local lighting can be used instead of raising the low illumination standard for the entire workshop.
(10)Comprehensive utilization of clean air flow. The heat recovery of the process and air conditioning system are directly beneficial energy-saving measures. For pharmaceutical cleanrooms that are free from dust particles, clean air flow is connected in series, connecting the cleanrooms according to the cleanliness level. The initial air supply is sent to a lower room before returning to the air conditioning unit, which can save several filters. For rooms with low purification requirements and focusing on eliminating waste heat, clean air flow can be cross utilized and a downward supply and upward return flow direction can be adopted. The downward supply can reduce the air supply speed, increase the air supply temperature, and reduce the temperature difference, while the upward return can increase the return air temperature.
(11)Consider heat recovery. When designing, consider using a heat recovery device. For systems with high exhaust air volume, the energy of the exhaust air can be recovered into the fresh air through a rotary heat exchanger or a tube heat exchanger, utilizing the principle of heat exchange, to pre-treat the fresh air. It is estimated that this can save over 25% in operating costs, which has considerable economic significance.
(12)Realize automatic control of the air conditioning system and variable frequency regulation of the motor. The cleanroom purification system environment can generally be divided into two time periods: manned operation time and maintenance cleaning time. The requirements for maintaining clean time for purifying air conditioning systems are relatively simple. The design of automatic control and fan variable frequency regulation can meet the different requirements of these two time periods. Although some investment was added in the initial investment, the saved operating costs after actual operation quickly recovered the initial investment, which has significant economic benefits. But there are corresponding strict requirements in construction and operation management.

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