❄️ Chilled Water HVAC Systems: Design Fundamentals for Commercial Buildings

What Is a Chilled Water System?

A chilled water (CHW) HVAC system uses chilled water — typically cooled to 44–45°F supply / 54–55°F return — as the heat transfer medium between a central chiller plant and air handling units distributed throughout a building. Chilled water systems are the dominant HVAC strategy for large commercial buildings (over ~50,000 sq ft) because they are more energy-efficient than direct expansion (DX) systems at scale, centralize maintenance, and allow flexibility in building layout.