Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
As you said, the full simulation models the HX as expected. Only the DOAS coil sizing neglects the HX.
From the Input Output Reference, "Input for Design Calculations and Component Autosizing, Overview":
The sizing calculations only recognize the presence of central heating and cooling coils, preheat and precool coils and reheat coils. These are assumed to deliver the various supply temperatures specified in the Sizing:System and Sizing:Zone objects. The impact of other components such as heat recovery, dehumidifiers, and pumps are not accounted for in the sizing calculations.
Repeating some suggestions in reply to helpdesk ticket 13109, if DOAS coil sizing is important for your study:
If the DOAS coils are chilled water and hot water, you can adjust the design inlet conditions in the coil object to the expected conditions after the heat recovery.
If the DOAS coils are not water coils, in the Sizing:System object, for the DOAS system, you could raise the cooling supply temperature and humidity ratio by the same amount that the heat exchanger lowers them so that the coil sees a smaller delta. Similarly, lower the values for the heating supply temperature and humidity. These won't be perfect, but should be reasonably close.
Run the Sizing Period simulations and report the coil loads hourly or by timestep and use the peak to hard-size the coils.
This is an open ]new feature request](https://github.com/NREL/EnergyPlus/issues/6663).
| | 2 | No.2 Revision |
As you said, the full simulation models the HX as expected. Only the DOAS coil sizing neglects the HX.
From the Input Output Reference, "Input for Design Calculations and Component Autosizing, Overview":
The sizing calculations only recognize the presence of central heating and cooling coils, preheat and precool coils and reheat coils. These are assumed to deliver the various supply temperatures specified in the Sizing:System and Sizing:Zone objects. The impact of other components such as heat recovery, dehumidifiers, and pumps are not accounted for in the sizing calculations.
Repeating some suggestions in reply to helpdesk ticket 13109, if DOAS coil sizing is important for your study:
If the DOAS coils are chilled water and hot water, you can adjust the design inlet conditions in the coil object to the expected conditions after the heat recovery.
If the DOAS coils are not water coils, in the Sizing:System object, for the DOAS system, you could raise the cooling supply temperature and humidity ratio by the same amount that the heat exchanger lowers them so that the coil sees a smaller delta. Similarly, lower the values for the heating supply temperature and humidity. These won't be perfect, but should be reasonably close.
Run the Sizing Period simulations and report the coil loads hourly or by timestep and use the peak to hard-size the coils.
This is an open ]new new feature request](https://github.com/NREL/EnergyPlus/issues/6663).
