How to Connect an AHU with a Chilled Water System
Connecting an Air Handling Unit (AHU) to a chilled water system is a common practice in commercial and industrial HVAC systems. This setup allows the AHU to cool the air using chilled water supplied from a central plant. Here's a step-by-step overview of how it works:
1. Supply and Return Piping
Chilled water from the central chiller plant is piped to the AHU through supply and return lines. The supply line delivers cold water to the AHU coil, and the return line sends the warmed water back to the chiller.
2. Cooling Coil Connection
Inside the AHU, the cooling coil is the key component. The chilled water enters the coil, absorbing heat from the air passing over it. The cooled air is then distributed through the duct system to the conditioned spaces.
3. Control Valve Installation
A 2-way or 3-way control valve is installed to regulate the chilled water flow based on the cooling demand. It is typically controlled by a thermostat or Building Management System (BMS).
4. Pump and Flow Control
A circulation pump ensures proper water flow to and from the AHU. Flow meters and balancing valves may be used to maintain correct flow rates.
5. Air Venting and Drainage
Air vents and drain points are installed at the coil to remove trapped air and allow maintenance.
Final Tips:
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Always insulate chilled water pipes to prevent condensation.
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Ensure proper flushing and pressure testing of the piping before operation.
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Coordinate with controls team to integrate AHU valves with the BMS.
