Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
It could be because plant loop is not meeting the setpoint.
From IORef:
Plant Supply Side Cooling Demand Rate [W]
This is the value of the net demand required to meet the cooling setpoint of the loop. If the loop setpoint is met for the current HVAC timestep, Plant Supply Side Cooling Demand Rate will equal sum of the total cooling demand from the demand side coils on the loop. It will also equal the cooling output of all chillers (or other cooling equipment) on the loop less any pump heat added to the fluid. For example, for a chilled water loop with one chiller and one pump serving one chilled water coil: Plant Supply Side Cooling Demand Rate will equal the chiller evaporator heat transfer less the pump heat to fluid, and it will also equal the chilled water coil total cooling output.
If the plant loop setpoint is not met, Plant Supply Side Cooling Demand Rate will equal the sum of the total cooling demand from the demand side coils on the loop plus the additional cooling required to bring the loop flow to setpoint. If the loop remains off setpoint for successive timesteps, the demand required to return to setpoint will repeat in each timestep until the loop reaches setpoint. For this reason, Plant Supply Side Cooling Demand Rate should not be summed over time, because it will overstate the demand whenever the loop is off setpoint
| | 2 | No.2 Revision |
It could be because plant loop is not meeting the setpoint.
From IORef:
Plant Supply Side Cooling Demand Rate [W]
This is the value of the net demand required to meet the cooling setpoint of the loop. If the loop setpoint is met for the current HVAC timestep, Plant Supply Side Cooling Demand Rate will equal sum of the total cooling demand from the demand side coils on the loop. It will also equal the cooling output of all chillers (or other cooling equipment) on the loop less any pump heat added to the fluid. For example, for a chilled water loop with one chiller and one pump serving one chilled water coil: Plant Supply Side Cooling Demand Rate will equal the chiller evaporator heat transfer less the pump heat to fluid, and it will also equal the chilled water coil total cooling output.
If the plant loop setpoint is not met, Plant Supply Side Cooling Demand Rate will equal the sum of the total cooling demand from the demand side coils on the loop plus the additional cooling required to bring the loop flow to setpoint. If the loop remains off setpoint for successive timesteps, the demand required to return to setpoint will repeat in each timestep until the loop reaches setpoint. For this reason, Plant Supply Side Cooling Demand Rate should not be summed over time, because it will overstate the demand whenever the loop is off setpoint
