One extra field in Boiler:HotWater

[Ski90Moo]

Issue overview

The following error appears when simulating Boiler:HotWater: Severe Output:PreprocessorMessage="ExpandObjects" has the following Fatal conditions: ~~~ SEVERE: Too many fields were found for the object: Boiler:HotWater ~~~ Number ~~~ expected=[17] ~~~ Number found=[18] Fatal Preprocessor condition(s) cause termination.

Current Behavior

EnergyPlus input file shows 18 fields:

Boiler:HotWater, Boiler Hot Water 1, !- Name NaturalGas, !- Fuel Type Autosize, !- Nominal Capacity {W} 0.8, !- Nominal Thermal Efficiency LeavingBoiler, !- Efficiency Curve Temperature Evaluation Variable Boiler Efficiency, !- Normalized Boiler Efficiency Curve Name Autosize, !- Design Water Flow Rate {m3/s} 0, !- Minimum Part Load Ratio 1, !- Maximum Part Load Ratio 1, !- Optimum Part Load Ratio Node 19, !- Boiler Water Inlet Node Name Node 24, !- Boiler Water Outlet Node Name 99, !- Water Outlet Upper Temperature Limit {C} ConstantFlow, !- Boiler Flow Mode 0, !- On Cycle Parasitic Electric Load {W} 1, !- Sizing Factor General, !- End-Use Subcategory 0; !- Off Cycle Parasitic Fuel Load {W}

Latest EnegyPlus InputOutput reference 23.2.0 indicates that there should be up to 19 fields. Number expected should be 19, not 17.

Expected Behavior

Steps to Reproduce

1. 2. 3. 4.

Possible Solution

Details

Environment

Some additional details about your environment for this issue (if relevant):

• Platform (Operating system, version):

• Version of OpenStudio (if using an intermediate build, include SHA):

Context

[buildingman07]

I am having the same issue in OpenStudio when trying to add a boiler to a hot water loop.

[eringold]

This is an issue that EnergyPlus had running ExpandObjects, which @jmarrec fixed here: https://github.com/NREL/EnergyPlus/pull/10288

EnergyPlus will attempt to run ExpandObjects when an HVACTemplate is detected in the idf. OpenStudio creates HVACTemplate objects when 'Use Ideal Air Loads' for an OS:ThermalZone is 'Yes', i.e. when the 'Turn On Ideal Air Loads' box is checked for a Thermal Zone tab in the OpenStudioApplication. One way to work around this failure is to not have that box selected for any zones.

An alternative way to use Ideal Air Loads that does not use HVACTemplates is to specify a ZoneHVACIdealLoadsAirSystem object, as in this measure (which replaces HVAC in all zones, so might not be directly applicable to your use case without modification).

[laiamusach]

I have the same problem but I don't have ideal loads on and I don't understand how you solved it.

[eringold]

@laiamusach can you share the model, or a way to reproduce the error?

[laiamusach]

design.zip I hope you can downloade it. Now I solve it but I still get some warnings that kind of mess with accurate results. This is an analysis of a small house that only uses heating with a diesel boiler. However, it says I don't have cooling loads and I quite don't understand what that means. I would be so glad if you could go a bit through the warnings cause I am a bit lost.

[Ski90Moo]

@laiamusach It appears your thermal zones do not have a cooling thermostat assigned. This is not the forum for troubleshooting your model. Please see unmethours.com.

[laiamusach]

Sorry for the inconveniences, I posted it in unmethours.com a few days ago as well.