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Bug - Evaporatively cooled condenser option for unitary template #33

Open afshinfaramarzi opened 3 months ago

afshinfaramarzi commented 3 months ago

We are trying to use unitary template to generate models with evaporatively cooled condenser, which appears to be a feature of the template. However, it does not work as expected.

Excerpts from template

Here are some lines in the template that lead us to believe that evaporative cooling is meant to be implemented:

https://github.com/sound-data/DEER-Prototypes-EnergyPlus/blob/4e78842f69fc55f35111cf24f4cd3fda60fbbd35/templates/energyplus/templates/system/unitary.pxt#L54

https://github.com/sound-data/DEER-Prototypes-EnergyPlus/blob/4e78842f69fc55f35111cf24f4cd3fda60fbbd35/templates/energyplus/templates/system/unitary.pxt#L572-L573

https://github.com/sound-data/DEER-Prototypes-EnergyPlus/blob/4e78842f69fc55f35111cf24f4cd3fda60fbbd35/templates/energyplus/templates/system/unitary.pxt#L603-L613

Example parameter inputs

We tested this option with the cases file shown below. ECC.csv

skip case_name :main_cool_coil_type
base DX-AIR
measure DX-EVAP

IDF outputs

Here are the relevant portions of the models composed using the cases file above.

Air-cooled: instance_base.txt

        AirLoopHVAC:UnitarySystem,
          MZ-VAV-Floor2 Unitary,     !- Name
          Setpoint,     !- Control Type
          ,  !- Controlling Zone or Thermostat Location
          None,                    !- Dehumidification Control Type
          ,!MZ-VAV-Floor2 Schedule,  !- Availability Schedule Name
          MZ-VAV-Floor2 Unitary Inlet Node,  !- Air Inlet Node Name
          MZ-VAV-Floor2 Unitary Outlet Node,  !- Air Outlet Node Name
          Fan:SystemModel,      !- Supply Fan Object Type
          MZ-VAV-Floor2 Supply Fan,  !- Supply Fan Name
          DrawThrough,             !- Fan Placement
          MZ-VAV-Floor2 Fan Mode Schedule,  !- Supply Air Fan Operating Mode Schedule Name
          Coil:Heating:Water,      !- Heating Coil Object Type
          MZ-VAV-Floor2 Heating Coil,  !- Heating Coil Name
          ,                        !- DX Heating Coil Sizing Ratio
          Coil:Cooling:DX:MultiSpeed,  !- Cooling Coil Object Type
          MZ-VAV-Floor2 Cooling Coil,  !- Cooling Coil Name
          No,                      !- Use DOAS DX Cooling Coil
...

            Coil:Cooling:DX:MultiSpeed,
              Computer EL4 Core Spc (G.C5) SZ-CRAC Cooling Coil,  !- Name
              ,                        !- Availability Schedule Name
              Computer EL4 Core Spc (G.C5) SZ-CRAC Unitary Inlet Node,  !- Air Inlet Node Name
              Computer EL4 Core Spc (G.C5) SZ-CRAC Cooling Coil Outlet Node,  !- Air Outlet Node Name
              ,                        !- Condenser Air Inlet Node Name
              AirCooled,               !- Condenser Type
              -25.0,                   !- Minimum Outdoor Dry-Bulb Temperature for Compressor Operation (C)
              ,                        !- Supply Water Storage Tank Name

Evap-cooled: instance_measure.txt

        AirLoopHVAC:UnitarySystem,
          MZ-VAV-Floor2 Unitary,     !- Name
          Setpoint,     !- Control Type
          ,  !- Controlling Zone or Thermostat Location
          None,                    !- Dehumidification Control Type
          ,!MZ-VAV-Floor2 Schedule,  !- Availability Schedule Name
          MZ-VAV-Floor2 Unitary Inlet Node,  !- Air Inlet Node Name
          MZ-VAV-Floor2 Unitary Outlet Node,  !- Air Outlet Node Name
          Fan:SystemModel,      !- Supply Fan Object Type
          MZ-VAV-Floor2 Supply Fan,  !- Supply Fan Name
          DrawThrough,             !- Fan Placement
          MZ-VAV-Floor2 Fan Mode Schedule,  !- Supply Air Fan Operating Mode Schedule Name
          Coil:Heating:Water,      !- Heating Coil Object Type
          MZ-VAV-Floor2 Heating Coil,  !- Heating Coil Name
          ,                        !- DX Heating Coil Sizing Ratio
!!!! Missing Condenser Type
!!!! Missing Min Outdoor Dry-Bulb
          No,                      !- Use DOAS DX Cooling Coil
...
!!!! No objects of class Coil:Cooling:DX:MultiSpeed.

Summary

Although templates hint at an understanding of evap-cooled condenser for a unitary system, there is a bug in the logic and it is not composing the model correctly. Lines like the one below seem to be the problem:

https://github.com/sound-data/DEER-Prototypes-EnergyPlus/blob/4e78842f69fc55f35111cf24f4cd3fda60fbbd35/templates/energyplus/templates/system/unitary.pxt#L572-L573

because the IF-clause that understands "DX-EVAP" is nested inside the IF-clause that only matches "DX-AIR".