Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Collecting the answers from above . . . The difference is latent cooling (at the coil), fan heat, pump heat, and outdoor air. Chiller False Load Heat Transfer is not included in Chiller Evaporator Cooling Rate, so that does not apply here. And if there is reheat, then you need to add the reheat coil output (whenever the cooling coil is active).
Working backwards
Chiller Evaporator Cooling Rate = Cooling Coil Total Cooling Rate + Pump Fluid Heat Gain Rate
Cooling Coil Sensible Cooling Rate = Zone Air System Sensible Cooling Rate + Fan Heat Gain to Air + Heating Coil Heating Rate (for reheat coils) + Net outdoor air load
The Net Outdoor Air Load = Zone Mechanical Ventilation Cooling Load Increase Energy + Zone Mechanical Ventilation Cooling Load Increase Due to Overheating Energy - Zone Mechanical Ventilation Cooling Load Decrease Energy
OUtdoor air is messy, because free cooling in cool weather is included in the Zone Air System Sensible Cooling Rate which represents the cooling delivered to the zone. (same thing as HVAC Terminal Unit Sensible Air Cooling in the heat gain report).
And the difference in Cooling Coil Total vs Sensible load, you just have to accept. There aren't any other simple outputs that can add up to that unless you have no outdoor air and your report all of the zone internal latent gains.
| | 2 | No.2 Revision |
Collecting the answers from above . . . The difference is latent cooling (at the coil), fan heat, pump heat, and outdoor air. Chiller False Load Heat Transfer is not included in Chiller Evaporator Cooling Rate, so that does not apply here. And if there is reheat, then you need to add the reheat coil output (whenever the cooling coil is active).
Working backwards
Chiller Evaporator Cooling Rate = Cooling Coil Total Cooling Rate + Pump Fluid Heat Gain Rate
Cooling Coil Sensible Cooling Rate = Zone Air System Sensible Cooling Rate + Fan Heat Gain to Air + Heating Coil Heating Rate (for reheat coils) + Net outdoor air load
The Net Outdoor Air Load = Zone Mechanical Ventilation Cooling Load Increase Energy + Zone Mechanical Ventilation Cooling Load Increase Due to Overheating Energy - Zone Mechanical Ventilation Cooling Load Decrease Energy
OUtdoor Outdoor air is messy, because free cooling in cool weather is included in the Zone Air System Sensible Cooling Rate which represents the cooling delivered to the zone. (same thing as HVAC Terminal Unit Sensible Air Cooling in the heat gain report).
And the difference in Cooling Coil Total vs Sensible load, you just have to accept. There aren't any other simple outputs that can add up to that unless you have no outdoor air and your you report all of the zone internal latent gains.
