oat's profile - activity

May I ask how Surplus Electricity Going To Utility is calculated as reported in the Electric Loads Satisfied table in the html file ?

May I also ask why Net Electricity From Utility is not equal to Electricity Coming From Utility minus Total On-Site Electric Sources?

I'm using the following Python code to query a SQLite output file produced by EnergyPlus:

import sqlite3
import os

sqlite_file = './test_sql_h.sql'

table_name = 'ReportDataDictionary'
id_column = 'ReportDataDictionaryIndex'
column_a = 'Name'
column_b = 'KeyValue'

# connect to the database file
conn = sqlite3.connect(sqlite_file)
c = conn.cursor()

# identify all unique variable names
c.execute(
        ' SELECT DISTINCT ({col}) FROM {tn} '.\
        format(tn=table_name, col=column_a)
        )
all_names_unique = c.fetchall()
for i in range(0, len(all_names_unique)):
    print(all_names_unique[i])

# commit changes and queries, and close the connection
conn.commit()
conn.close()

However, each variable name is enclosed in a pair of single quotation marks proceeded by the letter "u" as shown below.

(u'Zone Lights Electric Energy',)
(u'Zone Electric Equipment Electric Energy',)
(u'Zone Ideal Loads Supply Air Total Heating Energy',)
(u'Zone Ideal Loads Supply Air Total Cooling Energy',)

May I ask why the output is not the pure name of the variable?

Thanks.

I want to compare hourly irradiance level of each PV surface as simulated in EnergyPlus with that in Radiance.

May ask if there is a output variable which reports hourly irradiance level for each shading surface specified as PV panel?

Or is hourly irradiance level of a given PV surface = hourly AC electricity generated by the PV surface / Cell efficiency / PV surface area ?

"Surface Outside Face Incident Solar Radiation Rate per Area" will be reported for shading surface specified as PV gener

Thanks, MJWitte, for pointing out the source of error. I've identified the code which produced this error in the runEner

I'm using the Honeybee interface to run EnergyPlus simulation for a simple model.

I got the following severe error:

Program Version,EnergyPlus, Version 8.9.0-eba93e8e1b, YMD=2018.08.12 11:34,
* Severe * <root>[Output:Variable][Output:Variable 76][reporting_frequency] - "Simple" - Failed to match against any enum values.

I checked the IDF file, and the format of the two output variables as highlighted below seems OK:

Output:Variable,*,Surface Outside Face Incident Ground Diffuse Solar Radiation Rate per Area,hourly;

Output:Diagnostics,DisplayExtraWarnings;

Output:SQLite, Simple;

Output:Variable,My_PV_generator_system:DISTRIBUTIONSYSTEM,Electric Load Center Produced Electric Energy, Simple;

Once these two output variables on diagnostics and SQLite as highlighted above are removed in the Honeybee workflow, the simulation runs correctly.

However, without removing these two output variables: 1. the same Honeybee workflow works fine in another computer with the same software installation, and 2. the same IDF file also works fine independently through the EPLaunch.exe.

Another strange issue is that, as shown above, the EnergyPlus version is indicated as 8.9.0. However, I'm using EnergPlus 8.8.0 only currently....

May I ask if you can kindly advise what could have caused the severe error in this case?

severe error "Failed to match against any enum values" I'm using the Honeybee interface to run EnergyPlus simulation for

severe error "Failed to match against any enum values" I'm using the Honeybee interface to run EnergyPlus simulation for

Thank you very much, Eric, for your detailed advice. Will take a look of the references you suggested.

Thank you very much, David, for your advice.

My I ask what the difference between Zone Windows Total Heat Gain Energy and Surface Window Heat Gain Energy is?

It's explained in the E+ document that:

Zone Windows Total Heat Gain Energy [J]

The sum of the heat flow from all of the exterior windows in a zone when that sum is positive.

whereas

Surface Window Heat Gain Energy [J]

The total heat flow to the zone from the glazing, frame and divider of an exterior window when the total heat flow is positive.

Does this mean that the sum of the Surface Window Heat Gain Energy for all the windows of a given zone equals to the Zone Windows Total Heat Gain Energy of that zone?

However, the total across all the zones and surfaces for both variables are not the same, it seems.

Thank you, Aaron. I compared the components of both Surface Window Net Heat Transfer Energy and Surface Window Heat Ga

Thank you very much, Julien, for your detailed explanation. I didn't know that there is the 0.3W/m2 threshold applied fo

what is the difference betwee "Zone Windows Total Heat Gain Energy" and "Surface Window Heat Gain Energy"? My I ask what

May I ask how Generator PV Array Efficiency is calculated as it is not explained in EnergyPlus document?

The following are the output variables for a particular PV surface.

May I ask how is the Generator Produced DC Electric Power [W] calculated?

It seems it is not equal to:

Surface Outside Face Incident Solar Radiation Rate per Area [W/m2]

x Surface Area [m2]

x Generator PV Array Efficiency

The PV generator is specified in Honeybee as the following:

The hourly PV output for one day is:

Thanks, Julien. I realized that the ηcell: the module conversion efficiency or Cell Efficiency is not the Generator PV A

How is the Generator Produced DC Electric Power calculated? The following are the output variables for a particular PV s

The unit for energy related output variables is J by default as shown in the csv result file.

Is there a way to set the unit for these variables as kWh by adding a line of code in the IDF file?

I do understand that the following only change the unit for the HTML summary report, not the csv file:

OutputControl:Table:Style,CommaAndHTML,JtoKWH;

how to report "surface area" as an output variable in the CSV file? May I ask if there is a way to report the area of ea

how to report "surface area" as an output variable in the CSV file? May I ask if there is a way to report the area of ea

May I ask if the experts here can recommend entry level tutorial on how to model HVAC system in EnergyPlus and OpenStudio?

Currently, I'm using the Ideal Loads Air System to estimate cooling/heating loads and plug loads in teaching of energy modeling. However, for more realistic and detailed HVAC system design in practice, the workflow might be quite different and complicated.

I'd appreciate if you can suggest good textbook or tutorials for starters in this regard that explains the basics of HVAC system and the technical procedures to model typical HVAC systems in EnergyPlus and OpenStudio!

Thank you very much!