How Does a Cleanroom Chilled-Water HVAC System Work?
Chilled-Water HVAC System
A cleanroom chilled-water HVAC (Heating, Ventilation, and Air Conditioning) system is a type of cooling system commonly used in cleanroom environments to maintain desired temperature, humidity, and air quality conditions while providing precise and reliable control. The system operates using a network of chilled-water pipes and air handling units (AHUs) to deliver conditioned air to the cleanroom space. The system uses the mechanism of chilled water for cooling and heating purposes.
Here is a brief overview of how the system works:
- The Chiller: The system starts with a chiller unit, which cools the water to a low temperature, usually between 2°C to 7°C (35.6°F to 44.6°F), by removing heat from it. The chiller is essentially a refrigeration system that transfers heat from the water to refrigerant gas.
- Cooling Tower: As the refrigerant gas captures heat from the water, it needs to be cooled down. A cooling tower assists in this process by dissipating the heat into the environment through evaporation.
- Pumps: Chilled water is circulated through the system using pumps. There are usually two pumps in the system – one for chilled water supply and the other for chilled water return.
- Heat Exchangers: The chilled water travels through heat exchangers in AHUs located within the cleanroom. These heat exchangers transfer heat from the air to the chilled water, cooling the air before it is delivered to the cleanroom.
- Air Distribution: The cooled air is pushed through a network of air ducts to maintain an even temperature throughout the cleanroom. Since cleanrooms have specific air quality requirements, the HVAC system works with the air plenum and Fan Filter Units (FFUs) to remove contaminants from the air.
- Direct Digital Controls (DDC): A DDC control system helps maintain desired temperature and humidity levels in the cleanroom by monitoring and adjusting the chilled water flow, fan speeds, and other parameters.
By using a chilled-water HVAC system, cleanrooms can achieve precise and stable temperature and humidity control. This is crucial to ensure optimal performance and prevent contamination of sensitive processes taking place inside the cleanroom in various industries such as semiconductor manufacturing, pharmaceuticals, and biotechnology. It is crucial that a chilled-water HVAC system for cleanrooms maintains the specified temperature, humidity, and air quality levels at all times.
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