Report ASHRAE 62.1 with 100% Outdoor Air
I am working on LEED IEQp1 compliance and I am following the steps showed on the previous question and also using EnergyPlus/OpenStudio in order to get the Required Outdoor Air Intake Flow (Vot).
I have got the report with no problem but EnergyPlus report shows that most of the zones have 100% Outdoor Air Intake Flow and it´s not true.
I tried to get those values on my own and it seems to me that there is a mistake in Zone Ventilation Efficiency calculation because the value for Ev and Xs are the same in Energy Plus.
I have already checked the HVAC system configuration by clicking on the dotted line on the system configuration and setting as it follows: OS: Sizing: System: 100% Outdoor air in Cooling = No and OS: Sizing: System: 100% Outdoor Air in Heating = No.
Nevertheless, the report keeps getting OA% = 100% for most of the zones. Is there any other field I got to check in order to get a correct Required Outdoor Air Intake Flow (Vot) value? Am I mistaken anywhere else?
The simulation file is attached here
@Pithon I am looking into this. My initial conclusion is that there is indeed something fishy. I suggest changing from VentilationRateProcedure to ZoneSum for the single-zone constant volume systems. I haven't tested this yet, but believe it will give more reasonable results.
@Pithon I am having this same issue. Were you able to solve your issue?
@Anna Osborne, unfortunately I didn't solve completely this. In the end, I was forced to do everything right in the LEED Online platform.
I have a similar situation with a model. My opinion is that VRP is for design for a one time critical scenario. But during operation, unless you have DCV, air loops in a VAV system work based on demand from the VAV terminals. Setting VRP for a year simulation results in instances were demand from VAV terminals is low, and your VRP OA calculation is close/equal to the primary VAV terminal airflow demand, lowering the ventilation efficiency Ev below 0.5. I suggest to lock the maximum OA air to a fixed number and lock the minimum airflow fractions in VAV terminals. Min Zp is not available in EP.