The energy consumption of HVAC system accounts for about 60% of building energy consumption, so energy conservation of HVAC is particularly important in building energy conservation. The purification air conditioning system in the purification workshop is more chaotic and requires higher investment compared to general air conditioning systems, mainly reflected in factors such as large air supply volume, high fan pressure loss, high cooling and heating loads, and constant temperature and humidity requirements for clean air conditioning. Make the operating energy consumption of the purification air conditioning system about ten times higher than that of the general air conditioning system, adding the cost of producing products for factories and enterprises. Therefore, in the case of satisfying the production needs of high-precision products in enterprises and meeting professional production quality management standards, choosing energy-saving solutions for purification air conditioning systems will greatly reduce the operating costs of enterprises.

Firstly, let's understand the characteristics of the air conditioning system in the purification workshop (which is also the primary component of clean air conditioning energy consumption).

1： High air volume and high fan pressure head. The purification workshop achieves cleanliness standards by circulating and filtering sufficient air volume. The air volume is generally calculated based on the number of indoor air changes, usually 10 times or even dozens of times the volume of the room, especially in one-way flow cleanrooms such as Class 100 and Class 10, where the air change rate reaches several hundred times the volume of the room. The purified air volume is filtered through primary, secondary, and tertiary filters and transported to the workshop through longer air ducts, overcoming the resistance of other equipment and accessories in the system, resulting in a pressure loss of approximately 1000Pa. So if the air handling unit needs to supply such a large pressure head, it requires a matching power supply for power.

2： High temperature and humidity control requirements. The requirement for constant temperature and humidity in the purification workshop is to meet the production needs of the process. For example, in the manufacturing of certain electronic products, the control requirements for temperature and humidity are very strict. In medical and experimental animals, there are also clear requirements for the accuracy of temperature and humidity control. In order to achieve constant temperature and humidity, it is required that the air handling unit has at least cooling, heating, humidification, dehumidification and other functional sections, and requires precise control; Moreover, the water flow rate should be controlled using integral control, and the humidification amount should also be controlled using integral control or PID regulation to achieve higher control accuracy.

3： The air conditioning system has a high cold and hot load. Because there are many production equipment, high equipment power, and large heat dissipation in general purification workshops; The second compensation requires a large amount of fresh air for indoor exhaust and maintaining positive pressure values; Third protection structure heat dissipation and production personnel heat dissipation loads; So the cooling and heating load of the air conditioning system in the purification workshop is much higher than that of general air conditioning, and the planning and operation energy consumption of adding refrigeration equipment.

By understanding the primary part of energy consumption in the air conditioning system of a purification workshop, one can start from these reasons and develop energy-saving measures that are suitable for different levels of purification workshops, production environments, and production process requirements. The following energy-saving methods are proposed for analysis.

1： Select lower cleanliness levels and air exchange rates under satisfactory production process requirements.

The customer and the planning and construction party need to communicate and confirm this requirement, and select the environmental requirements that are suitable for the production of their own products. It does not mean that the higher the purification level, the better, as it corresponds to high investment and high energy consumption operation. In addition, some suppliers of the same level of purification workshops, due to a lack of experience, blindly follow the planning standards for air exchange rates and often achieve higher air exchange rates. For example, the standard air exchange rate for static clean 10000 level workshops is 15-25 times/h. This range is only a reference value for our planning. If we do not take into account the customer's product production process and environmental factors, blindly select higher air exchange rates, although it meets the purification requirements, it adds investment and operating power. Therefore, the service we provide to our customers is to meet the production needs of the process, select the appropriate cleanliness level and air exchange rate, and provide energy-saving purification system solutions.

2： Separate the purified air volume from the air volume that satisfies the cooling and heating load of the air conditioner.

For workshops with higher purification levels, such as those with purification levels of 1000, 100, and higher; Perhaps workshops with larger areas and higher floors require much higher purification air volume than the air conditioning supply required to meet satisfactory temperature and humidity requirements. If the purified air volume is selected as the air conditioning air volume together, that is, if the purified air volume and the air conditioning air volume are not separated, then all the return air must be collected and processed through the combined air cabinet. When a large air volume passes through the air treatment equipment, the resistance will be high, and the energy consumption of the fan will increase. Together, in order to dehumidify, all return air must be treated to the dew point state, and then in order to prevent the indoor temperature from being too low, it is necessary to reheat the supply air. Cold and heat offset, causing unnecessary waste. If the air conditioning and purification air volumes are treated separately, the purification air volume will only be filtered, which can greatly shorten the length of the purification air volume transportation pipeline; As for the air conditioning airflow, reducing the airflow can save on air cooling and heat treatment, and also reduce the transportation cross-section and energy consumption. As shown in Figures 2 and 3.

3： Reduce the loss of fresh air volume.

In the air conditioning system of the purification workshop, the fresh air load accounts for a large proportion. Therefore, reducing the fresh air volume is of great significance for reducing the energy consumption of the clean air conditioning system. The fresh air volume in the purification workshop is primarily determined by the exhaust volume and the fresh air required to maintain positive indoor pressure. To reduce the fresh air volume of the system, the first priority is to reduce the exhaust air volume of the system. In IC factories, various toxic and harmful gases are generated due to the use of acids, bases, and organic solvents in semiconductor production. Therefore, the exhaust hood of the device may directly exhaust the equipment, using a local exhaust method with a small air volume to control the dispersion of harmful gases and discharge them outdoors. Thus reducing the amount of supplementary fresh air. The second point is to reduce the leakage of workshop air flow. Maintaining positive air flow is related to the controlled pressure difference and sealing of the clean room. The pressure difference is primarily determined by the nature and standards of the clean room, therefore, in order to reduce and maintain positive air pressure, the sealing of the system should be improved first. In this regard, strict control should be exercised over the sealing of the clean room during the planning and construction process, such as reducing the number of doors and windows, ensuring that doors and windows have outstanding sealing functions (such as adding sealing strips under doors), and closing doors entering and exiting the clean room in a timely manner; Methods for controlling the bonding degree of color steel plate joints and the quality of adhesive sealing technology during the construction process, as well as sealing the voids through the color plate.

4： Reasonable selection of air conditioning system equipment.

The unit cooling load of the purification workshop is several to ten times higher than that of general comfort air conditioning. In addition to dealing with relatively large purification air volume factors, another primary factor is that workshop equipment has a large heat dissipation capacity, including production equipment heat dissipation, combined air conditioning equipment heat dissipation, FFU and other air conditioning equipment heat dissipation, and lighting heat dissipation. Therefore, a large amount of cooling capacity is required. In this regard, the required cooling load for the workshop should be carefully calculated. Through detailed communication with the customer, specific equipment power and quantity should be obtained to accurately calculate the cooling load. To prevent unrealistic and blindly increasing the cooling capacity of the workshop's air conditioning, and to increase the investment in air conditioning equipment in the early stage and the waste of surplus in the later stage, and to increase the energy consumption and operating costs of air conditioning. Similarly, regarding the standard calculation of the head and air pressure of the water pump and fan in the air conditioning system, the first priority is to plan and arrange the water system and air duct system reasonably, and minimize pipeline resistance as much as possible. Secondly, accurate hydraulic calculation of the water system and air duct system is required to obtain accurate pump lift and fan pressure head, to prevent excessive head and pressure head and increase operating costs.

In summary, the factors causing energy loss in the purification workshop cover all aspects. We not only need to start from the source and provide precise and suitable purification system solutions for customer enterprises, but also need to improve construction quality, optimize the construction process, and flexibly select energy-saving construction plans according to local conditions during the construction process; Moreover, in order to provide professional training on the operation and protection of purification systems for enterprises in the later stage, enterprises can adopt correct protection and application methods, which is conducive to saving workshop energy loss and reducing production costs. With the rapid development of China's technology industry, more and more purification workshops have emerged. Energy saving air conditioning systems in purification workshops have become an important means for manufacturers to reduce production costs, increase competitive advantages, and defeat opponents. Therefore, energy conservation of clean air conditioning systems has become a hot topic in our research and a focal point of concern for enterprises.

Article source: Hunan Purification Engineering http://www.jmyujie.com/