TECHNICAL FEATURE FIGURE 5 Cool day afternoon operation of a condenser water TIER system. 42°F CHWS & R 66°F 54°F Cooling Only vs. Centrifugal 70°F 100°F 130°F 80°F TES Tank HWS & R 60°F Two-Position Modulating CHW HW CW FIGURE 6 Warm day afternoon operation of a condenser water TIER system. 42°F CHWS & R 66°F 54°F Cooling Only vs. Centrifugal 79°F 100°F 130°F 87°F 84°F TES Tank HWS & R Two-Position Modulating CHW HW CW Figure 6 shows a high cooling load condition as might occur during the afternoon of a warm day. In this scenario, one of the red heat recovery chillers has been indexed into " cooling mode " and is connected on the evaporator side to the chilled water loop while rejecting heat at low lift to the condenser water loop. Any building heating loads are served by the one remaining heat recovery chiller indexed to the hot water loop. A mixing O CTO B E R 2 0 2 1 ashrae.o rg ASHRAE JOURNAL 19 71°F CW Pumps 72°F HX 69°F Heat Recovery Screw 60°F 80°F Trim Heat ASHPs HR CW Pumps 87°F 87°F Tower Pumps Cooling Towers CW Pumps Heat Recovery Screw 80°F HX 60°F 80°F Trim Heat ASHPs HR CW Pumps Cooling Tower Tower Pumps Cond Evap Cond Evap Cond Evap Cond Evap Cond Evap Cond Evap Cond Evap Cond Evaphttp://ashrae.org