How to Achieve High Delta T (∆T) at Peak and Part Load Eric M. Moe IDEA International Conference Abu Dhabi, UAE January 2007 42/55 Plant (13°∆T Design) 80 OATwb 70 Temperature (deg F) Low Delta T (∆T) is a Common and Expensive District Cooling Problem 90 60 50 40 30 - lost plant capacity 20 - added complexity - wasted energy - poor control 10 0 CHWST - Primary CHWST - Secondary Delta T - Primary Delta T - Secondary Low ∆T Limits Capacity / Wastes Energy 12000 Rated Tons of Running Chillers 10000 More (or larger) equipment required to serve the loads 8000 Cooling (Tons) Low ∆T means fewer ton-hrs/gallon and sq-ft/installed ton 6000 Chillers Pumps Fans Pipes TES 4000 2000 Actual Cooling Load 0 $$$$ $$$$ $$$$ $$$$ $$$$ Pressure Independent Control is Fundamentally Different Applied at Coils and Heat Exchangers • • • Simple direct connect Direct connect w/ booster pump and bypass Indirect w/ heat exchanger 5 psid 5 psid T FM FM Control distribution pumps to minimum differential pressure, not supply or return FM Optimizes Cooling Coil Heat Transfer ARI Cooling Coil 100% 90% % Cooling Load DeltaPValves Minimum Acceptable Coil Performance Design Delta T 80% 70% 60% 50% 40% 30% Conventional 20% 10% 0% 0% 20% 40% % Flow • • • optimizes cooling coil heat transfer eliminates effect of pressure changes sized by flow rate alone 60% 80% 100% Prevents / Addresses Low ∆T Delivers Systemwide Benefits 100 90 Exelon Thermal Midway Airport Temp (deg F) 80 70 Outside Air 60 CHW Return 50 CHW Supply 40 Delta T 30 20 10 0 Time on August 1, 2002 • ∆T > 18°F design (avoid penalties) • Minimum installed plant capacity • Uncommonly high efficiency • No terminal pumps, crossovers • No balancing valves Why Strive for High ∆T? Heat and cool more space with less energy, equipment, complexity and cost. For more information about pressure independent control as well as applications support, please contact: Eric M. Moe 425-483-1297 [email protected] www.flowcontrol.com