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2020-10-12 14:47:21 -0600 received badge  Nice Answer (source)
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2020-09-21 08:00:25 -0600 answered a question energyplus runtime api clear_all_states function missing

Hi there, I believe I responded to you on the helpdesk as well, but I'll just summarize that yes, that was an oversight.

2020-08-24 21:26:42 -0600 commented answer Python interacts with EnergyPlus

Sure. In case 1, you call EnergyPlus as a library, starting with some other tool. For instance, you write a Python scr

2020-08-14 09:27:28 -0600 answered a question Unable to run OpenStudio due to PYTHONHOME error on Mac

Those messages may be unrelated to the actual problem with the simulation. With some of the python work that was implem

2020-07-01 12:53:32 -0600 commented answer Python interacts with EnergyPlus

The bug fix was released, but as it includes changes that only a very small percentage of users would need, we didn't br

2020-05-11 20:37:11 -0600 answered a question Python interacts with EnergyPlus

As of version 9.3.0, EnergyPlus has two ways to interact with a running simulation using Python. A new C API has been

2019-09-30 11:53:41 -0600 commented answer How to control EnergyPlus parameters for each timestep using Python?

This feature is going to be a major part of our work in FY20, so be on the lookout for some capability added to the Spri

2019-08-06 11:05:55 -0600 answered a question EnergyPlus 8.6 Windows Installation File Missing

The release notes on that page clearly state why the package is not present there: Windows packages for EnergyPlus 8

2019-07-30 08:55:48 -0600 answered a question How to control EnergyPlus parameters for each timestep using Python?

As an aside, we are actively working on enabling a feature to allow exactly what you are looking for, a Python-based EMS

2019-04-09 12:35:27 -0600 answered a question Python Library for EnergyPlus Runtime Language (ERL)

First, welcome to EnergyPlus. I'm glad you started with the tutorials, and your goal seems interesting and very much do

2019-01-04 07:32:38 -0600 commented question Command line interface (CLI) and EPMacro

We moved to Ubuntu 18.04. That's probably it. Ubuntu 14.04 is approaching end-of-life.

2019-01-03 15:59:33 -0600 commented question Command line interface (CLI) and EPMacro

I cannot reproduce this problem. I ran the downloaded input file, with San Francisco weather, using the command line ab

2016-06-23 11:55:21 -0600 commented answer Heat Recovery Chiller Autosizing
2016-03-10 14:23:07 -0600 commented answer Simulation results change without editing the model

Yeah, the order dependence is known, but that's all contained within a convergence loop so that the numbers eventually come out similar. For example, if you order the surfaces differently, the resulting converged state will be very close but not exact, so the HVAC cycling may occur on different time steps. Nothing like the boilers simply never running, etc.

2016-03-10 11:23:10 -0600 answered a question Simulation results change without editing the model

So as part of the EnergyPlus development process, we run tests on every commit and we get 100% repeatable results. Not just down to a tiny epsilon, but the same outputs. I don't see any possibility that it spontaneously started producing different results. The only possibility I see is that if your simulation is relying on the Energy+.ini file and it is pointing to some other folder to find some outside dependency and that accidentally changes. From an EnergyPlus standpoint, if you give the same idd, idf, and epw, (and any other outside dependency files such as csv schedules), it will produce the same results.

2015-10-06 19:13:55 -0600 commented answer Does someone have any better, more up to date tutorials

I posted a link to more up to date demo videos as per the original question, and I got a -1. Opposite day! :-P

2015-10-06 18:16:00 -0600 commented answer Does someone have any better, more up to date tutorials

Can i haz unmet hourz video by the kat?

2015-10-06 17:00:06 -0600 answered a question Does someone have any better, more up to date tutorials

The Youtubes haz all the videos.

2015-10-06 16:42:45 -0600 edited question Does someone have any better, more up to date tutorials

I have been trying to teach myself how to use openstudio, but none of the videos or resources that I am finding are up to date with the latest version (V 1.0.13). The ribbon is completely different, and some of the buttons on the ribbon aren't even included in the newer version. Does anyone know of good tutorials that are up to date with V1.0.13.

2015-10-05 15:31:30 -0600 received badge  Civic Duty (source)
2015-09-18 13:58:56 -0600 edited answer Can energy plus output indoor temperature at the 1-minute frequency?

Setting the output variable reporting frequency to "Detailed" or "Timestep" should accomplish what you want.

2015-09-01 13:15:03 -0600 commented question I will buy a drink at ASHRAE EMC ...

I could throw a wrench in your plans by deleting my account...

2015-08-12 08:41:20 -0600 commented question I do not have a file error energyplus

This can happen when EnergyPlus hard-crashes. Can you provide some more information about your setup? Which version of OpenStudio, etc.?

2015-07-28 12:00:48 -0600 commented answer Regression testing scripts

That repo is where defect files are maintained which could contain proprietary info. We can't open it up. We can, however, move the test scripts. They could even go right in NREL/EnergyPlus as far as I am concerned. @lefticus what will this affect on the CI end of things?

2015-07-25 00:40:07 -0600 commented answer Using PlantEquipmentOperation:OutDoorDryBulb to control Condenser Equipment

@kbk78 I think we should leave UnmetHours at this point and move to work together directly on the GitHub issue tracker. I added this info to the above answer so that if you agree, it can be accepted, and this can be closed and we'll work it out over there. If not, let me know.

2015-07-24 16:17:19 -0600 commented question UnmetHours on Mobile?

Sure, although I like having a dedicated app for some things so that it can provide push notifications, etc. I think I'll look at using an RSS feed app since UnmetHours offers that.

2015-07-24 16:11:47 -0600 received badge  Student (source)
2015-07-24 16:08:54 -0600 asked a question UnmetHours on Mobile?

I love interacting with UnmetHours in my spare time. Is there a convenient way to access it from my mobile device? Perhaps an existing app that allows connecting to sites like UnmetHours? Or maybe a dedicated UnmetHours app? I couldn't find one in the Google Play Store but maybe it's available in the Apple App Store.

Thanks for any advice!

2015-07-24 15:55:40 -0600 answered a question Temperatures at specific points in a modelled space

This is a great question. I'll speak to the EnergyPlus side since that is the basis behind OpenStudio anyway.

Most simulations in EnergyPlus assume a well-mixed zone. This assumes that the entire air volume in a space can be represented by a single thermodynamic state, so the air near the wall is the same as the air in the middle of the room. In this case, no, a spatial temperature distribution is neither calculated, nor available for report. However, there are specialized room air models available that allow for stratified, or non-uniform, air temperature distribution in the space. Look up the options available in the docs here to learn about the differences. Each model allows different calculation capability, and thus different report variables, to allow output of temperatures at different locations within a space.

2015-07-24 15:45:43 -0600 received badge  Organizer (source)
2015-07-24 15:41:32 -0600 edited question Scheduling VRF system

I am trying to model and compare results with actual measurement from a commercial building with 4 VRF heat pump and 7 Thermal Zone. What is the best way of using the schedules:- Requirements:- The 4 outdoor units are set to VRF and operate only between morning 5:30 to evening 8 pm. My understanding

  1. seven schedules on OS each for each zone with set temperature 74 and other times 100+(so that the system does not operate) or
  2. 4 schedules for each systems and common for common zones.

I am using VRF systems and VRF terminal units. My system can only provide heating or cooling at a time not simultaneously. Are my selections ok? Also for creating new schedule I did could not select the type of schedule for such operation. What other schedules will be required for the full model i.e.

  1. people
  2. equipment
  3. outdoor units
  4. Terminal units
  5. any other.
2015-07-24 15:25:49 -0600 answered a question why plastic pipes are used in radiant cooling system

I'd say first that this isn't really the appropriate spot for this question, unless, for example, it's about how to enter thermal properties of plastic into EnergyPlus for use in thermal calculations. :-)

But I think to answer your question, it has to do with safety/pressure guidelines, the lifetime of the material, and as with most all decisions, material cost.

Editorial note: I imagine that the plastic might actually help in at least one facet of the thermal behavior of the system. If the pipe was extremely conductive, it is possible that the fluid would radially conduct a significant amount of heat in a very short length of the pipe, reducing the uniformity of the system across the entire floor/wall/ceiling. Having plastic may help dampen the heat transfer in the system to spread out the heat transfer over the entire surface.

2015-07-24 15:13:38 -0600 answered a question Load Profile of Call Centers

It seems like this situation makes it even simpler than a typical building model. You should be able to assume a constant occupancy schedule unless the building design clearly calls out that the 24/7 schedule goes down in the evening. The lighting schedules should be similar during the day, then when the sun goes down, the lights should remain at design conditions throughout the overnight hours. You might be interested in using a lighting control for your building model, as that would take the burden of choosing a lighting schedule off of you and onto the simulation model.

2015-07-24 15:08:22 -0600 answered a question Two Splitter-Mixer Supply Pairs on Condenser Loop

So I would imagine this would look like:

Demand side
    N-number of branches in parallel, each of which contain a pump and a heat exchanger for each zone

Supply side
    M-number of branches in parallel, each of which contain a pump and a cooling tower

Since this would employ pumping on the demand side, the plant loop will need to be told what type of control to use, and there are some restrictions applied to pumping when you do branch pumping with primary/secondary systems. But it should get you close, and should allow you to control the supply setpoint as with simpler plant configurations, and without the need to workaround with a separate plant loop.

Is there a reason this wouldn't work for you?

2015-07-24 14:53:03 -0600 answered a question Is there anyone who is familiar with Airpak3.0 model file format

<necromancer answering="" old="" unanswered="" posts="">

So there is a document here, where Chapter 3 describes the files used by AirPak. The most interesting note, however, is in Section 4.3 where they note that dxf can be imported directly.

2015-07-24 14:47:02 -0600 answered a question Cooling/Heating Auto-sizing Reporting in EnergyPlus

The eio file contains the autosized results. If you are running EnergyPlus by itself, it should be named eplusout.eio. If you are running it with EP-Launch, it should be named <modelname>.eio. And if you are running from OpenStudio, you'll have to check the run results folders to find the eio in there.

An example of this output file is below, which shows a header followed by the autosized flow rates, loop volume, and capacities.

! <Component Sizing Information>, Component Type, Component Name, Input Field Description, Value
 Component Sizing Information, PlantLoop, COOLER_LOOP, Maximum Loop Flow Rate [m3/s], 1.60462E-002
 Component Sizing Information, PlantLoop, COOLER_LOOP, Plant Loop Volume [m3], 18.05199
 Component Sizing Information, Pump:VariableSpeed, COOLER_LOOP SUPPLY PUMP, Rated Flow Rate [m3/s], 1.60462E-002
 Component Sizing Information, Pump:VariableSpeed, COOLER_LOOP SUPPLY PUMP, Rated Power Consumption [W], 457.15707
 Component Sizing Information, Chiller:Electric:EIR, COOLERCHILLER, Design Size Reference Chilled Water Flow Rate [m3/s], 1.60462E-002
 Component Sizing Information, Chiller:Electric:EIR, COOLERCHILLER, Design Size Reference Capacity [W], 343023.18468

If you are looking for the entire capacity for the building, you'll have to have a script read this file (it's CSV, so many options there), and add all the component sizing entries, then be a little smart about adding them all up so that you don't ever double count anything.

2015-07-23 18:15:19 -0600 answered a question Using PlantEquipmentOperation:OutDoorDryBulb to control Condenser Equipment


So, I did some digging today with your example file. Unfortunately it has revealed some issues with that operation scheme that are going to require a workaround if you need to use this before the next release of E+.

I have opened an issue on our GitHub site here that details what I have seen so far today. If you have a GitHub account, please feel free to engage in the conversation on that issue. This is a high priority to me, so I anticipate having the issues fixed up soon, but the fix won't be available in a major release until our September 30 release.

In the meantime, if you need an immediate workaround, you could simply pull the outdoor dry bulb from the weather file for every hour, and then create an hourly 0/1 schedule for when the temperature is above or equal to the switch temperature, then one for when it is below. These schedules could be used in the CondenserEquipmentOperationSchemes object to schedule two separate PlantEquipmentOperation: instances. Of which neither should be the OutdoorDryBulb. I would imagine something like:

    Condenser_Loop Operation,            !- Name
    PlantEquipmentOperation:CoolingLoad, !- Control Scheme 1 Object Type
    AboveScheme,                         !- Control Scheme 1 Name
    AboveSchedule,                       !- Control Scheme 1 Schedule Name
    PlantEquipmentOperation:CoolingLoad, !- Control Scheme 2 Object Type
    BelowScheme,                         !- Control Scheme 2 Name
    BelowSchedule;                       !- Control Scheme 2 Schedule Name

where the AboveSchedule/BelowSchedule are the values you created above outside of E+. (You could use Schedule:File for convenience there). Then the operation schemes would look like:

    AboveScheme,                 !- Name
    0,                           !- Load Range 1 Lower Limit {W}
    100000000,                   !- Load Range 1 Upper Limit {W}
    CoolingTower Equipment List; !- Range 1 Equipment List Name

    BelowScheme,                 !- Name
    0,                           !- Load Range 1 Lower Limit {W}
    100000000,                   !- Load Range 1 Upper Limit {W}
    FluidCooler Equipment List;  !- Range 1 Equipment List Name

Thanks for helping identifying this.

So, after the comment by @kbk78, it is clear that there is a set of issues that need to be addressed, and this isn't the location for the conversation to figure it all out (and it will be a lengthy process to work through them all). I would recommend that we close this conversation and continue to work out all the issues together on the GitHub issue page if you already have or are willing to register on GitHub. If you are satisfied with that, please take this as the final answer for the UnmetHours conversation, and we'll work to address this over on the other side.

2015-07-23 11:18:55 -0600 edited question Using PlantEquipmentOperation:OutDoorDryBulb to control Condenser Equipment

I have a cooling tower and a fluid cooler in a EnergyPlus model. We are trying to control the operation based on outside temperature. If the Temperature is less than 40F the fluid cooler operates. If the temperature is greater than 40F the cooling tower operates. The following are the objects setup in the model:

    FluidCooler Equipment List,

    CoolingTower Equipment List,

    Condenser_Loop Scheme 1,
    -32,4.5,FluidCooler Equipment List,
     4.5,50,CoolingTower Equipment List;

    Condenser_Loop Operation,
    Condenser_Loop Scheme 1,

The condenser Loop operation is further referenced by the CondenserLoop Object.

However, Hourly outputs indicate both units operating at all times during the year. Is this setup not adequate for this type of control?


Scheduled Condenser operation File:C:\fakepath\CondDB_Sch.idf.gif

2015-07-23 11:02:54 -0600 commented question Using PlantEquipmentOperation:OutDoorDryBulb to control Condenser Equipment

Which version of E+ are you using?

2015-07-23 11:02:54 -0600 received badge  Commentator
2015-07-23 10:01:26 -0600 commented question Using PlantEquipmentOperation:OutDoorDryBulb to control Condenser Equipment

Should be sufficient, some additional info could help resolve the problem.

What's your pumping scheme? What is the pump size compared to the design flows of the two units? Do you have a supply side bypass on the condenser loop?

2015-07-23 09:54:36 -0600 received badge  Autobiographer
2015-07-23 09:52:18 -0600 commented answer EnergyPlus crash - forrtl: severe (157): Program Exception - access violation

The Fortran code isn't explicitly posted by the E+ team, but Unmet Hours has a few major release versions of the Fortran code posted under the open source license. You can look at for the packages.

2015-07-22 17:07:47 -0600 answered a question EnergyPlus crash - forrtl: severe (157): Program Exception - access violation


Looking at the source from EnergyPlus, line 2468 of ScheduleManager.f90 is in the function that gives the current schedule value at a point in the simulation. At that line, the function is checking whether EMS is overriding a schedule. In the current C++ code, it corresponds to right about here.

Without seeing the actual example file, I'm guessing on this project you are using EMS. It appears maybe there is an indexing problem that the code tries to access either a too-high, or zero schedule index in the internal array, which causes the access violation. I know the project might be over, but in case you are still having this issue, if you are able to send the EMS logic that (I presume) you are using, it would be helpful in debugging.

Suggestions to fix would be:

  • Check to make sure you initialize the EMS variable you are using to store the schedule index to a meaningful value before using it
  • If that doesn't reveal the problem, post the EMS logic you use to help diagnose the problem here, or
  • Post the file to the EnergyPlus Helpdesk for further developer assistance
2015-07-17 09:35:45 -0600 commented answer EnergyPlus V8.3 Crash

They shouldn't result in a hard crash, EnergyPlus handles most erroneous situations by providing the error file. If possible, submit your input file to the EnergyPlus HelpDesk ( so that the development team can use it as the basis for filing an issue and adding error handling so that the crash is changed to an informative severe error.

2015-07-17 09:11:39 -0600 commented answer OS 1.8.0/EP 8.3./Ubuntu: How to run IDFVersionUpdater ?

Can you provide the output of:

$ ldd /usr/local/share/openstudio-1.8.0/EnergyPlus-8-3-0/PreProcess/IDFVersionUpdater/IDFVersionUpdater

(Where ldd is L D D)

2015-07-16 08:53:52 -0600 answered a question OS 1.8.0/EP 8.3./Ubuntu: How to run IDFVersionUpdater ?

If you are using 14.04, that package should already be installed. It is listed in the default packages installed for Trusty here. If you aren't using Ubuntu 14.04, then it's not a platform we support, although you may be able to just apt-get install libgtk2.0-0.