Simulating a single room + radiator in EnergyPlus

asked 2016-02-15 01:13:10 -0500

Misagh Ebrahimpour
11 ●2

updated 2016-02-15 10:29:23 -0500

__AmirRoth__

4436 ●5 ●17 http://bleedinggreenna...

Hi there,

I want to simulate a single room with a simple radiator. To do so, I have applied "ZoneHVAC:Baseboard:Convective:Water" + boiler in a loop. The simulation doesn't have any problem, however, in the reported outputs the variable "Zone Air System Sensible Heating Energy" is not zero!!!! Does it mean that another heat supplier (with air flow) in addition to the radiator is considered in the simulation???

Thanks in advance

Comments

Where do you see the "Zone Air System Sensible Heating Energy"? HTML table, CSV, ?

Aaron Boranian ( 2016-02-15 11:20:22 -0500 )edit

"Zone Air System Sensible Heating Energy" is a variable in Output:Variable, and I saw the value of this variable in the released spreadsheet.

Misagh Ebrahimpour ( 2016-02-15 11:47:52 -0500 )edit

Hello, I am new to energyplus. I also want to make a simple room with only a radiator, but I am not sure how to set it up. Would you please share your idf file? thank you very much.

Yuyang Gong ( 2020-08-29 19:46:00 -0500 )edit

@Yuyang Gong what kind of radiator (hot water, electric, steam)? EnergyPlus has a specific object for each kind of radiative/convective heating equipment, and the best way to see how it is set up is within example file IDFs that are part of the EnergyPlus installation.

Aaron Boranian ( 2020-08-30 14:44:05 -0500 )edit

hot water radiator. Thanks for your reply, however, I didn't find the example file only with a radiator. Could you please tell me the name of the file? Thanks a lot!

Yuyang Gong ( 2020-09-02 09:34:28 -0500 )edit

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answered 2016-02-15 12:25:12 -0500

Aaron Boranian

13830 ●76 ●24 http://bigladdersoftware.com/

Sounds like you are including the Zone object's output for "Zone Air System Sensible Heating Energy". According to the documentation, this output:

Reports the heating or cooling delivered by the HVAC system to a zone. These values are calculated by multiplying the supply air mass flow rate by the difference between the supply air temperature and the zone air temperature. This does not always indicate the operation of heating or cooling coils. For example, cooling will be reported if the supply air is cooled due to the introduction of outside air, even if all coils are off.

In other words, even if you model an air loop without central heating or terminal reheat, when the air terminal delivers supply air that is hotter than the zone's air, this will be reported as positive sensible heating for this output variable.

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I have considered "ZoneHVAC:Baseboard:Convective:Water" and a boiler in a loop because I just want to have the radiator as the heat supplier. I have not considered anything related to Air supply. I dont know why this Air supply is added to the system. It might be due to the zone autosizing, but I am not sure about it.

Misagh Ebrahimpour ( 2016-02-15 12:57:45 -0500 )edit

It doesn't have to be a central air supply, it could be zone-level HVAC (window AC, FCU, etc.) or possibly Ideal Loads Air System. Set the first 5 input fields of the "SimulationControl" object to 'Yes', then set the 'Reporting Frequency' field of the Output:Variable object to "Hourly" or "Detailed". Run a simulation, then check the times where the output CSV file report non-zero sensible heating. This is how you determine whether it occurs for sizing periods, the entire simulation with the weather file, or both.

Aaron Boranian ( 2016-02-15 14:16:08 -0500 )edit

The value of "Zone Air System Sensible Heating Energy" is not zero in sizing and run period. There isnt any central air supply nor any other air supplier. Can I send you the idf file in a way?

Misagh Ebrahimpour ( 2016-02-15 15:56:09 -0500 )edit

Sure, can you put it on Dropbox so that I can download it? If not, my email is aaron.boranian@bigladdersoftware.com. If there are any files that the IDF references (schedule, ground temperatures, etc.) I will need those as well to run a simulation.

Aaron Boranian ( 2016-02-15 16:24:02 -0500 )edit

I sent an email.

Misagh Ebrahimpour ( 2016-02-15 23:28:22 -0500 )edit

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Simulating a single room + radiator in EnergyPlus

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Simulating a single room + radiator in EnergyPlus