If your chilled water plant is costing more to operate than expected, your system may be suffering from Low Delta T (temperature) syndrome. Delta T is the temperature difference between chilled water supply and return. When that difference is significantly lower than the system’s design intent, efficiency drops and energy costs rise.
Low Delta T prevents chillers from operating at optimal performance, often forcing additional equipment to run unnecessarily to meet cooling demand. The result? Higher energy consumption and increased wear on your system.
Common Causes of Low Delta T
Low Delta T can stem from several mechanical and control-related issues, including:
- Dirty or improperly sized coils
Coils that are fouled with dirt or oversized for the application cannot transfer heat effectively, reducing temperature change across the system. - Improperly sized or malfunctioning control valves
Valves that are too large or do not fully close allow excessive water flow, limiting proper heat exchange. - Poor system balance or oversized equipment
Improper hydraulic balance or equipment that exceeds actual load requirements can disrupt designed flow rates and temperatures.
How to Fix Low Delta T
The right solution depends on identifying the root cause. Common corrective actions include:
- Rerouting piping and rebalancing the system to restore proper hydraulic balance and bring water flow back to design conditions.
- Cleaning coils to improve heat transfer performance.
- Upgrading or optimizing controls to better modulate valves and match system demand.
If you’re seeing higher-than-normal return water temperatures or rising energy bills, now may be the time to have your chilled water system evaluated. Proactive diagnosis and maintenance can restore efficiency, reduce operating costs, and extend the life of your equipment.
