Chillers in HVAC Systems hvac design filtration and air quality ahu zoning

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Chillers are a vital component of HVAC systems in pharmaceutical, biotech, and healthcare facilities. They provide reliable cooling for cleanrooms, process equipment, and utilities, ensuring that sensitive environments and products remain within strict temperature and humidity limits.

A chiller is a refrigeration machine that removes heat from water (or a water-glycol solution) and supplies chilled water to air handling units (AHUs), fan coil units, or process equipment. The chilled water absorbs heat from the system and returns to the chiller to be cooled again, creating a continuous cycle.

• Air-Cooled Chillers
   
  • Use ambient air to reject heat.
     
  • Easier to install and maintain.
     
  • Suitable for small-to-medium facilities.
     
  • Higher energy consumption compared to water-cooled systems.
     
• Water-Cooled Chillers
   
  • Use cooling towers and condenser water to reject heat.
     
  • More efficient for large facilities with high cooling loads.
     
  • Require more infrastructure (cooling towers, pumps, water treatment).
     
  • Common in pharma plants due to large process requirements.
     

• Compressor: Heart of the chiller, compresses refrigerant.
   
• Evaporator: Heat exchanger where chilled water is cooled.
   
• Condenser: Rejects heat to air or water.
   
• Expansion Valve: Regulates refrigerant flow.
   
• Control System: Monitors temperature, load, and efficiency.
   

• Cleanroom Air Conditioning: Supplies chilled water to AHUs, maintaining temperature (typically 18–24°C) and humidity (40–60% RH).
   
• Process Cooling: Supports bioreactors, centrifuges, lyophilizers, plasma fractionation units, and cold rooms.
   
• Utility Systems: Chilled water loop integrates with WFI (Water for Injection) production, compressed air dryers, and other critical systems.
   
• Redundancy: Pharma projects often include N+1 chiller redundancy to avoid downtime.
   

• Variable Speed Drives (VSDs): Optimize compressor and pump performance.
   
• Free Cooling Option: In colder climates, chillers can bypass compressors and use ambient air.
   
• Building Management System (BMS): Controls chiller sequencing, load sharing, and energy optimization.
   

• Chillers must comply with ASHRAE, GMP, and ISO standards.
   
• Water quality management (for water-cooled chillers) is essential to prevent scaling, corrosion, and microbial growth.
   
• Proper sizing and zoning are critical — undersized chillers lead to unstable conditions, while oversized systems waste energy.
   

chillers are the backbone of HVAC and utility systems in pharmaceutical facilities. They ensure controlled environmental conditions in cleanrooms and provide process cooling for critical equipment. Correct selection, redundancy, and integration into BMS are essential for reliable and compliant operations.