The air conditioning system in clean rooms has significant differences with commercial and residential buildings. Clean rooms are very energetic because the volume of room air change per hour is between 10 to 50 times more than a normal room, so they have high operating and construction costs. In the past, less attention was paid to energy consumption in clean rooms But today, due to the rise of energy carriers, more attention has been paid to saving energy and reducing energy consumption in clean rooms.
They do not state the general rules and do not reflect the special cases of clean rooms. Only the details of some energy saving cases can be found in the two valid German standards VDI 2083 standard 1 and the British standard BS 8568: 20132. Special attention to optimizing the air change factor and It is necessary to capture the production of particles in a clean room, because as the level of cleanliness of the space increases, the rate of air exchange will increase. Sound and energy reduction are important.
In clean rooms, energy consumption can be greatly saved by optimizing energy and correct designs. Here are some of the methods:
1. Choosing a room class: First of all, it must be determined in which class a room should be placed in terms of pollution. Critical and non-critical areas should be identified and special conditions should be considered based on their needs. It is not necessary that all spaces are considered critical areas with high cleanliness. It is better to guarantee the protection conditions of these areas by considering lower cleanliness classes. .
2. Use as small environments as possible: Save on using small environments instead of large rooms, the smaller the room, the lower the cost of installing HEPA filters on the entire ceiling and the less filter fan unit is required.
3. Room air volume: Look for ways to optimize and reduce room air volume. Reducing air recirculation will result in good energy savings.
4. Equipment size optimization: Fan and motor power is directly proportional to the intended air volume.
5. Static air and pressure :. Improper design of air ducts will cause a significant pressure drop in the ducts and will cause the selection of a fan with a higher pressure, resulting in higher costs.
The use of variable frequency drives (inverters) is essential to save on fan size, pumps, cooling towers, and some chillers. Using variable speed systems consumes 15-30% less energy than fixed speeds.
6. Optimize air distribution and reduce pressure drop: Fan energy is directly related to pressure drop. Be careful in choosing the air distribution system because a lot of energy can be stored in this area, strategies to reduce pressure drop are:
• Reduce airflow and prevent zigzagging
• Selection of cooling coils and filters with low pressure drop
• Keep the speed down
• Choose high-efficiency filters that give cleaner air and consume less.
• Avoid excessive security margins
7. Correct placement of equipment:
The installation location of the fan motor must be in a suitable place in terms of energy saving.
Placing the motor in the flow path warms the indoor air. But it makes access to the engine difficult.
8. Outdoor air optimization: Most of the ventilation in a clean room is caused by outside air. Large volumes of this air require ventilation and increased pressure. By limiting this amount, we can save a lot of energy.
According to the considerations of energy consumption in clean rooms, Andishegaran Jame Sanat Iranian Company has designed and built a clean room, all clean room air conditioners are optimized motors equipped with inverters in the control panel, adjustable in different cycles and low-consumption lights Are.
1-The VDI 2083: guidelines define the requirements of air purity, of work places … transportation cleaning, commercial management and energy management for cleanrooms.
2-BS8568:2013 is a new British Standard that gives recommendations on reducing energy consumption and maintaining energy efficiency in new and existing cleanrooms and clean air devices.