antifx's profile - activity

Hey!

I want to implement the following control-strategy:

• If the room temperature is below 19°C, the heating systems should be on until the temperature is 25°C
• Once the temperature is 25°C, the heating system should be switched off until the temperature is again below 19°C

I think this control strategy is often called "hysteresis" (see http://nearbus.net/wiki/images/c/c0/H...)

Is there an integrated module or do I have to use EMS?

Thank you very much for your help

Hey!

I have a question regarding energyPlus calculation methods: I want to simulate a building with a low-temp radiant element in a concrete core slab (m_flow and temperature are given by measured data). Since I get wrong results (the surface temperature is to high compared to measured data and results from other simulation programs) , I want to argue the reasons for these differences. I got some hints from a colleague but I want to ask you a) if that hints are plausible and b) if you probably know additional reasons:

1)EnergyPlus calculates the sub-models “low-temp-rad element”, “wall” and “zone” separately and successive + that is a problem when it comes to low-temp-read systems: Does that mean that there is now data exchange/feedback during the simulation?

2) The CTF method in combination with a massive concrete slab + low-temp radiant element could cause deviations since the CTF method is not suitable for walls with high capacities?

3) EnergyPlus may or may not achieve the given low-temp-radiant inputs (m_flow, temperature, etc.)

Thank you very much for your help!

I tried the following: change at 00:00 to the next hour; change 00:00 at the end of the months to the next months, change in the minute filed: 00:000 to 60:00 --> https://www.dropbox.com/s/d3ibs9p81z0... does not work

Thank you for your answer. The building I want to simulate has no Basement: Which objects do I need? Site:GroundDomain:Slab + also GroundHeatTransfer:Control, Materials, Slab:BoundConds, etc.? Thank you for your help!

Hey, I want to simulate the ground temperature using the "slab programm" (Eplus-Versino 8.3).

GroundHeatTransfer:Control: Run Slab Procesor Yes
GroundHeatTransfer:Slab:BoundConds,
TRUE,                    !- EVTR: Is surface evapotranspiration modeled
TRUE,                    !- FIXBC: is the lower boundary at a fixed temperature
10,                      !- TDEEPin {C}
FALSE;                   !- USRHflag: Is the ground surface h specified by the user?

GroundHeatTransfer:Slab:BldgProps,
10,                      !- IYRS: Number of years to iterate
0,                       !- Shape: Slab shape
4,                       !- HBLDG: Building height {m}
22,                      !- TIN1: January Indoor Average Temperature Setpoint {C}
22,                      !- TIN2: February Indoor Average Temperature Setpoint {C}
22,                      !- TIN3: March Indoor Average Temperature Setpoint {C}
22,                      !- TIN4: April Indoor Average Temperature Setpoint {C}
22,                      !- TIN5: May Indoor Average Temperature Setpoint {C}
22,                      !- TIN6: June Indoor Average Temperature Setpoint {C}
22,                      !- TIN7: July Indoor Average Temperature Setpoint {C}
22,                      !- TIN8: August Indoor Average Temperature Setpoint {C}
22,                      !- TIN9: September Indoor Average Temperature Setpoint {C}
22,                      !- TIN10: October Indoor Average Temperature Setpoint {C}
22,                      !- TIN11: November Indoor Average Temperature Setpoint {C}
22,                      !- TIN12: December Indoor Average Temperature Setpoint {C}
,                        !- TINAmp: Daily Indoor sine wave variation amplitude {deltaC}
0.1;                     !- ConvTol: Convergence Tolerance

GroundHeatTransfer:Slab:Insulation,
0,                       !- RINS: R value of under slab insulation {m2-K/W}
0,                       !- DINS: Width of strip of under slab insulation {m}
2,                       !- RVINS: R value of vertical insulation {m2-K/W}
2,                       !- ZVINS: Depth of vertical insulation {m}
1;                       !- IVINS: Flag: Is there vertical insulation

GroundHeatTransfer:Control,
test,                    !- Name
No,                      !- Run Basement Preprocessor
Yes;                     !- Run Slab Preprocessor

GroundHeatTransfer:Slab:Materials,
1,                       !- NMAT: Number of materials
0.16,                    !- ALBEDO: Surface Albedo: No Snow
0.4,                     !- ALBEDO: Surface Albedo: Snow
0.94,                    !- EPSLW: Surface Emissivity: No Snow
0.86,                    !- EPSLW: Surface Emissivity: Snow
,                        !- Z0: Surface Roughness: No Snow {cm}
0.25,                    !- Z0: Surface Roughness: Snow {cm}
6.13,                    !- HIN: Indoor HConv: Downward Flow {W/m2-K}
9.26;                    !- HIN: Indoor HConv: Upward {W/m2-K}

GroundHeatTransfer:Slab:MatlProps,
2300,                    !- RHO: Slab Material density {kg/m3}
1200,                    !- RHO: Soil Density {kg/m3}
650,                     !- CP: Slab CP {J/kg-K}
1200,                    !- CP: Soil CP {J/kg-K}
0.9,                     !- TCON: Slab k {W/m-K}
1;                       !- TCON: Soil k {W/m-K}

I run EP-Launch / Utilities Slab / i got the following error message: specified file missing for utility: Slab: ....out_bsmt.idf

Then i tried to run the normal launch / single input file

I get the error message: Specified file missing for utility: Slab

PrelimOutput: Improper slab entered.  Describe slab using EquivalentSlab object or similar.

Is this even the right way to simulate the ground :) ? Thank you very much for your help!

Hey, I have a schedlue-file for internal gains (Watt). I tried:

OtherEquipment,
    InternalGain,            !- Name
    8FF727,                  !- Zone or ZoneList Name
    InternalGain,            !- Schedule Name
    EquipmentLevel,          !- Design Level Calculation Method
    ,                        !- Design Level {W}
    ,                        !- Power per Zone Floor Area {W/m2}
    ,                        !- Power per Person {W/Person}
    0,                       !- Fraction Latent
    1,                       !- Fraction Radiant
    0;                       !- Fraction Lost

does not work. Do I have to enter a design level (max. of my schedule) and %of this as schedule?

Hey, i have following measured weather data that i would need in EnergyPlus (10min values):

• Temperature Air
• Rel.Hum
• WindSpeed
• WindDirection
• IDiff_H
• IGlob_H

Can i read 10min values in E+? What do I write for all other values (which are not available, like Horizontal infrared radiation etc.?). How can i convert this txt file to an epw file? Thanks for your help!

Hey, I want to model urban quarters (buildings, and the grid): What is the limit in EnergyPlus regarding number of zones (just the building + ideal load (no HVAC)). Is it possible to model for example 1 000 zones (1-5 zones per building)

Kind regards

Hey, I am trying to use Eppy for the first time and I have a question (from the Tutorial) regarding :

iddfile = "../eppy/resources/iddfiles/Energy+V7_2_0.idd"
fname1 = "../eppy/resources/idffiles/V_7_2/smallfile.idf"

As I understand, the idd file is an input data dictionary file which contains a list of all possible EnergyPlus objects and a specification of the data each object requires. So the .idd file is the same for all projectes, right? So shound i create a new file (in the Tutorial) iddfile, or should i set the path to " C:\EnergyPlusV8-1-0\Energy+.idd"?

I tried to copy the file C:\EnergyPlusV8-1-0\Energy+.idd in the working directory.

Then I set:

fname1 = "D:\Tools\EnergyPlus \Energy+.idd"

error: IDDAlreadySetError: IDD file is set to: ../eppy/resources/iddfiles/Energy+V7_2_0.idd

Thank you for your help!

Hey, for example I have the following models in EnergyPlus:

1. A “basic model”
2. A model with HVAC 1
3. A model with HVAC 2

Now I want to change something in the “basic model” (for example a geometry) - but I don’t want to change this in all 3 models. Is there a possibility to build such a “base-model” where all changes will be applied automatically in the “test models”?

Thank you very much: If I would just want to know, how much energy I need for heating from the actual room-temperature to a given set point temperature, would it be possible to calculate it that way: Q = VolumeRoom * density * cp * (Tset – Troom). Then calculate the thermal power for a given internal gain?

I implemented a simple room model in matlab (incl. weather data) - output is the roomTemperature. Now i want to calculate the ideal thermal energy which is neede for a constant room temperature. Is it common to calculate it with constant mass flow or constant supply-temperature?

Given: The room-volume, the room temperature

I want to calculate: The power of an idealHeater (each timestep)

$Q = c \times m \times \Delta T$ --> ??

I have the following "strange" situation: If I am running a normal 1zone simulation in EnergyPlus, the Zone AirTemperature is between 6,5 and 7°C for a day in January. If I am adding "OutputDiagnostics:ReportDuringWarmup" ( otherwise all the same), the Zone Air Temperature is between 21 and 22°C. Does anyone have an idea?

Thank you very much! I have created the object: InternalSource, LowTemperatureRadiant:VariableFlow and a Thermostat.

Do I need to implement the whole HVAC System (PlantLoop, etc.)? I am new to EnergyPlus and OpenStudio and I tried it in OS, but it is not that easy - besides, we don't need the whole HVAC in our model, just concrete core activation incl. measured supply temperature.

Is there a possibility, to model something like a "ideal source/sink" for the LowtemperatureRadiant + Construction:InternalSource - without the wohle HVAC system? And if so, how would be a proper way to do that (inside OS would be easier for the start).

Thank you very much

There is no default value in loads/temperature convergence tolerance. Tutorials recommend: for temperature (0.4 default); loads tolerances (0.04 default). In the most example files there is a Temperature convergence tolerance of 0.005. With this value I get the following severe error:

* Severe * CheckWarmupConvergence: Loads Initialization, Zone="zone1" did not converge after 25 warmup days.

* ~~~ * See Warmup Convergence Information in .eio file for details.

* ~~~ * ...Environment(RunPeriod)="GRAZ - AUT IWEC Data WMO#=112400"

* ~~~ * ..Max Temp Comparison = 0.22 vs Temperature Convergence Tolerance=5.00E-003 - Fail Convergence

* ~~~ * ..Min Temp Comparison = 0.21 vs Temperature Convergence Tolerance=5.00E-003 - Fail Convergence

Is a temperature convergence tolerance of 0.4 a proper value?

Regarding my question i read this: Object: Site:GroundTemperature:BuildingSurface "Otherwise, take the indoor air temperature and subtract 2C as a reasonable starting value to use for most commercial applications in the U.S."

So should I simulate (in my example a 1 zone house) without HVAC (the house is located in europa/germany) - take the averrage monthly room temperature and substract 2C - and this are the values for Site:GroundTemperature:BuildingSurface?

And if there is a HVAC system - same approach (modeling without HVAC, set ground temperature)?

Thank you very much.

Hey,

how is a proper way to model the ground(temperature) in E+(i use Version 8.1)? Is there maybe a easy way (where the ground temperature depends just on the outside temperature)?

Thank you very much!

Hey, I want to model a simple one-zone building with concrete core activation in the ceiling. The supply temperature of the water should be imported (measured data) by constant flow rate. I would try that through schedule.fiele; the heat flow should be calculated through simulation. - Is it possible to implement concrete core activation in EnergyPlus (maybe as a template) – if so, how? - Is the workflow with a schedule:file for importing the measured supply temperature a good way?

Thank you very much!

I have a question regarding the OS Version + Legacy OpenStudio SketchUp Plug Version. In all tutorials i found so far ( http://nrel.github.io/OpenStudio-user... ) the legacy open studio plugin for sketch up is different to the latest version i dowloaded. For example:There is no dropdown for OpenStudio User scripts (templates); or a "create spaces from a diagram" button, and so on.

Is it better to download an older version of the plugin (if so, which one?)

Hey, i have a question regarding the workflow HVAC in energyPlus:

Is it easier to implement HVAC directly in energyPlus or in openStudio? Is it possible to build HVAC in openStudio and export an IDF file and run the simulation in energyPlus?

Thank you very much!!

Is it possible to import (txt, csv) files into EnergyPlus for running time-series simulations (changing a variable with every time step). For example, I want to model a concrete core heating/cooling system and the supply temperature and mass flow should be set to measured values (time step 10 minutes).

Or do I have to write them by hand into schedules?

Hey,

i have the following question/problem:

I build a model in SketchUp (legacy Version 1.0.11) (in my exaple 1zone: measurement 3,2m x 4,2m x 2,3m) and inport the .idf file into EnergyPlus Editor (Version 8.1) --> under 0006 building surface details, there is not the right geometry (vertices have values like: 3,1042..). I tried to set the right origin in sketchup - but does not work. Maybe someone can help.

Kind regards!!