HVAC engineers

Understanding "Approach" in Chiller Systems: Causes, Impacts, and ASHRAE-Based Best Practices In chiller system performance, one critical parameter that is often overlooked but highly indicative of system health is the Approach Temperature. What is Approach? Approach refers to the temperature difference between: Evaporator Approach: Leaving chilled water temperature vs. refrigerant evaporating temperature Condenser Approach: Leaving condenser water temperature vs. refrigerant condensing temperature A low approach indicates efficient heat transfer, while a high approach signals performance degradation. ASHRAE Guidance What is a "Good" Approach? Based on industry best practices and references from ASHRAE: Evaporator Approach (Typical Range): 1-3°C (1.8-5.4°F) →Excellent / Clean condition 3-5°C (5.4-9°F)  → Acceptable, monitor trend > 5°C (9°F)  →Indicates fouling or performance issue Condenser Approach (Typical Range): 2-4°C (3.67.2°F) →Good performance 4-6°C (7.2-...