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RE: [EnergyPlus_Support] Annual Peak cooling variable ?



Sorry, I am not going to comments on this subject any more.  On the other  hand, why not. so that others can  understand more on what is being discussed.
 
If the EPlus going to provide you with what you wanted, the decision is theirs.

All I am pointing out is that I do not understand why the maximum peak value of a variable after simmulation should be a different variable from its own set.  To me, it must be one value in that variable listed in ESO.  You said that the ESO only provides hourly result.  That is because you did not requet the timestep values to be stored in your IDF.  If the peak maximum value is not in the timestep values, then how do you create it? 

As I said that the spread sheet would give you the max peak value, if the number is in the .csv file.
I do not know whether you are doing annual simulation with the epw or your extreme conditions.  In either way, the peak value is can be extracted by using max and min function at the day interval cycle.  The 365 day peak values can then be processed again using the max and min function.  The formulae need only to be written once, for one display format. 
 
Alternatively, you can write a simple program to do the extraction directly from one or all of the .ESO files.
 
To me, 4000 Btu/h is not the total size of HVAC equipment.  It is only a demand value for an air loop at one particular time.  Did you obtained this value after the parametric run?  .idd file does not contain all the variables names.  .rdd and .edd have the variable or node names.  Maximum peak value is only one value in a variable, and is therefore not available in the .rDD file.
 
 
 
 
 
 
" To get the max of max of the 1080 results, get the min and max on the last two rows of 1080 sheets of the spread sheet.
  • Incorrect, when looking at the top and bottom rows of the 1020 runs the numbers are the Min/Max of the Annual Average, not the Annual Min/Max.
  • ...find that hourly is a sufficient level of granularity for detailed analysis of chosen results-
    ...to need to be able to show the maximum annual cooling load as a single number (rather then the annual average as currently possible) How is this average obtain  
    Li, I have responded to your comments in bullets;

    I am sorry to be blunt.
    • Please do, however be sure to actually respond to the question of the user not your own assumptions of what the question should be.
    I am not interested to see your PCM parametric jobs. They should be your proprietary information.
    • I like to share, and as Senior analyst at Phase Change Energy Simulations I can do so if I please, and if you did look at the info you would realize how very wrong you are.
     PCM material has to be modelled as a capacitor, battery, and a capacitor in electrical equivalent.  I do not think, you know this.  I do not have to show you what I know, in engineering design and simulation.
    • Thanks- and I respect your knowledge, but your comments are not respectful of the actual questions, also it does not matter what technology the model uses so far as the problem of E+ outputting the  average annual cooling load to csv rather then the peak. (window size or SHGC could just as easily create the same problem)
    What is the total size of the HVAC equipment?       
    • 4000 Btu/h
     An energy saving building may not need any HVAC equipment.
    • Agreed, but for this west faceing top floor dorm room in Los Angeles this is not practicle.
    As I said to extract the min and max value from the .ESO file is very simple.  They are aready there.  You do not know how to do it quiectly is your own problem.
    • If you actually read the post, (or Linda's response) or looked at the examples provided you would realize that the max value can not be printed to csv from eso with readvarseso because it is not in the idd.
     You ask for hourly average to be stored in the .ESO, what else do you expect?
    • Incorrect, I have annual set for sensible cooling rate and for sensible cooling energy, the other values are hourly so that further analysis of cause and effect on an hourly basis can be studied if required.
     To get the max of max of the 1080 results, get the min and max on the last two rows of  1080 sheets of the spread sheet.
    • Incorrect, when looking at the top and bottom rows of the 1020 runs the numbers are the Min/Max of the Annual Average, not the Annual Min/Max.
     "the linked optimisation rules are the objective functions of first cost vs total consumption.If you can reduce the first cost and minimize total consumption than you have an optimal design."  You need not worry about these.  Call a tender, the manufacturer will provide all te answers, and you simply select one.   All you need to provide is the building and the added demand, and the comfort level..  What you need to be involved is the demand minimization.
    • The demand is what the system is being designed upon, so the first cost is determined by the size of the system.
    To show the maximum and minimum values is simple.  They are already shown in the ...SZ.csv. 
    • You can not plot the values from the szs.csv as single numerical for thousands of simulations.
     For a person who never looked at the timestep results and never listed them in the .ESO, I have nothing more to add.
    • I use the timestep feature from time to time, (and evreytime for final analysis of szs.csv) but find that hourly is a sufficient level of granularity for detailed analysis of chosen results- the challenge is to use the model to find the chosen results to do more detailed analysis of, hence the reason to need to be able to show the maximum annual cooling load as a single number (rather then the annual average as currently possible)
     I do not think, we need to discuss this further, as I was only wanted to show you where to fine the readVaseso.exe documentation.
    • Thanks, but I am unsure how you are assuming I did not read the documentation prior to posting, (I think that users should read the documentation prior to posting, and even specified that I did so when I said "  Prior to posting this searched documentation for readvarseso, read every page of documentation (1832 to 1834 input output manual and pages 34 to 36 of "tips and tricks" and page 206 of "axillary programs")  I do not see any documentation as to how one would attain the information from readvarseso that is not contained in the Input Data Dictionary.   If there is a way to use .RVI files, or to set the IDF to report the maximal value, or to use get the maximum data out of the .ESO files that would be great."
    For someone who never does parametric studies, has a computer too slow to run full annual simulations and does not read the post before responding I am surprised you have had such a bad attitude about something you obviously are not knowledgeable about. 
    Thanks for your response, it further allowed me to make my case by having to explain the same thing many times to you, here it is again encase you still do not understand:
    • The problem is, when choosing annual output for sensible cooling rate is reported as annual average rather then annual maximum, this causes the output to not reflect what design iteration has the lowest peak load and corresponding cooling system size. This problem could be the same for heating. 
    • This problem is based on  2 wall insulation thickness, 5 roof insulation thickness, 2 window U value, 2 solar heat gain coefficient, 4 PCM roof, 4 PCM wall options for a total of 1020 design iterations, so is evaluating envelope options to reduce peak cooling loads. (not just PCM options)



    Jeremiah D. Crossett  | Senior Analyst  |  Phase Change Energy Solutions
    120 E. Pritchard St.  | Asheboro, NC 27203  | Mobile 503-688-8951
     

      






    On Tue, Sep 18, 2012 at 12:58 PM, YuanLu Li <yli006@hotmail.com> wrote:
     


    I am sorry to be blunt.
     
    I am not interested to see your PCM parametric jobs. They should be your proprietary information.
     
    PCM material has to be modelled as a capacitor, battery, and a capacitor in electrical equivalent.  I do not think, you know this.  I do not have to show you what I know, in engineering design and simulation.

    What is the total size of the HVAC equipment?   An energy saving building may not need any HVAC equipment.   
     
    As I said to extract the min and max value from the .ESO file is very simple.  They are aready there.  You do not know how to do it quiectly is your own problem.
     
    You ask for hourly average to be stored in the .ESO, what else do you expect?
     
    To get the max of max of the 1080 results, get the min and max on the last two rows of  1080 sheets of the spread sheet.
     

     
    "the linked optimisation rules are the objective functions of first cost vs total consumption.If you can reduce the first cost and minimize total consumption than you have an optimal design." 
     
    You need not worry about these.  Call a tender, the manufacturer will provide all te answers, and you simply select one.   All you need to provide is the building and the added demand, and the comfort level..  What you need to be involved is the demand minimization.
     
    To show the maximum and minimum values is simple.  They are already shown in the ...SZ.csv. 
     
    For a person who never looked at the timestep results and never listed them in the .ESO, I have nothing more to add.
     
    I do not think, we need to discuss this further, as I was only wanted to show you where to fine the readVaseso.exe documentation.

     Dr. Li  

     
    Date: Tue, 18 Sep 2012 11:55:36 -0700

    Subject: Re: [EnergyPlus_Support] Annual Peak cooling variable ?

     
    Linda, and Brent- I will be submitting this to the help desk for consideration for the wish list later on today- and note that in my request the same (or possibly more useful) result could be accomplished if there was a way to report the total component cost to output variable) 
    1. Total size of HVAC equipment
    2. Total amount of items that reduce HVAC equipment size
    With the use of objective functions users can examine tradoffs that allow the minimal HVAC equipment size and this will have a byproduct of minimizing energy consumption but at the lowest first cost. 

    Dr. Li,
    Thanks for your comments but-----You never cease to amaze me with your presumptions about what might be useful outside of your non market driven single design iteration ddy only runs.  I have read the documentation and no the average annual does not correlate to the smallest calculated system size. As Linda said there is not currently a way to do this, possibly you did not read the entire post.


    If you want to see what I am dealing with to possibly understand why this is needed for parametric studies or optimization routines you can download the 1020 simulation run from here:
    user: nrgsim
    passcode: globalnrgmodel 

    No one, except you, would ask  for the max peak value, to be displayed as a separate variable and cannot get it from the spread sheet yourself. 
    • Check the old list by searching for requests to have the annual cooling loads reported to csv and you will notice that I am not the only one with this request.
    • Think about this: Say a user has 2 wall insulation thickness, 5 roof insulation thickness, 2 window U value, 2 solar heat gain coefficient, 2 
    A simple program would extract the time and values from the ESO file, and give you an output, variable name, value min at time min, value max at time max..May be not simple, if you only code using Microsoft Visual series SDK.  I believe that the consol mode is still it there..
    • This is not possible for thousands of parametric options or millions optimization options because of the file structure of directories that are populated with the results.
    Annual max and annual min are EPW dependent data, and are already given in the .stat file.  Environment, annual and runPeriod has nothing to do with the max single peak value..
    • The value I am referring to would be to have a setting in the output varrible reporting frequency that provides an option of the model results to produce minimum or maximum values from the .eso file, the epw file is non-relevent to this requirement.
    The ReadVarsESO.exe file is in the PostProcessor folder.  There is also a batch file example there.
    • Obviously
    There is a number of exercise for you to do in the AdvancedOutput folder of the exampleFiles folder.  The instructin is in ExerciseOutput1 Instructions.pdf.
    • Obviously, but this does not address or solve the issue.
     
    After you have used the .rvi file to select the required variable to the .csv file, click on the cloumn and ask the spread sheet to show the max and min value.  It will be a waste of resources to create these two values as  separate variables..
    • This is incorrect- currently E+ averages the annual values then prints those to CSV, so when sorting with the spreadsheet the values that are sorted put the highest and lowest AVERAGED values. This correlated to number 288 down the list for for the run that had the lowest MAXIMUM system size as reported to HTML/ESO.
     
    This is not the first time that "how to use .rvi file" was asked in the forum. 
    • You provided relevant and helpful  feedback to a user on July 13th about a similar subject of RVI, but that was an entirely different request than this. 
     The variable names in the .rvi file are those in the header of the .eso file.  If the variable is not in the Outpupt variable list, it will not be there.  If the variable name  is not in the .rdd file, it will not be generated during simulation.   This is why you cannot generate your own name with a "max" in it..
    • Obviously, this is what I am requsting to be added to E+ as a new feature to solve the problem that E+ is producing annual averages for a value that should not be averaged, and would be useful to have MIN/MAX reported to csv via the readvarseso, and is only possible if it is added to the IDD.
    As you use 60 as timestep for simulation, all the variable will reported in one minute interval.  If you asked for hourly result, of cource, the value must be avaraged.  I have mentioned to you many times, that I do not use averaged daily, monthly and annual result.
    • Incorrect- I use 60 timesteps for all of my runs becuse I model PCM's (required to be no less than 20) and when not modeling PCM's for increased accuracy. The hourly results can not be used for large scale parametric or optimisation studies because the requirement is to have single annual numbers for each iteration- it is impossible to run millions of models and compare hourly values. 
     If you add the names listed below in the IDF, all of them will be in the .ESO file as hourly averaged.  Only when you have more than 250 columns, then you need to change the 250 to no limit and then use .rvi file to customize the .csv file.
    • Obviously,(this is in the documentation becuse it is the limit of excel, but could be overriden for viewing results from .eso or .sql) and why would needing one peak annual output of sensible cooling rate need more than 250 colums?
     Add two more rows at the bottom of the spread sheed and fill them with formula to extract max. and min. from all the data above.
    • Incorrect, this would produce the MIN/.MAX of the annual averaged number produced in the .eso file. If it was that simple I would not have posted this. For that to work the max values would have to be the starting numbers in the csv file but are not.
     End of your task.
    • Not possible without max values, as I said the max value comes in at # 288 of 1020 runs because the current logic is to report to csv the annual average. O
     I do not think that your 1000 odd parameter simulation data mean anything, if you to not have a linked optimization rules.  
    • Respectfully I do not think you have ever done such a parametric simulation, the linked optimisation rules are the objective functions of first cost vs total consumption.If you can reduce the first cost and minimize total consumption than you have an optimal design. This can be done via parametric studies if you wish to explore all design alternatives or by optimisation if you wish to solve the equation with a single optimal design. Again respectfully I do not think you have any idea what you are talking about when it comes to parametric or optimisation runs as you have said that you have not done one before. 
    The peak cooling load cannot be reduced by simulation. The value itself does not mean anything.    You need to determine what is the source causing the maximum, it it is not the weather condition.
    • Obviously the weather can not change and yes the goal is to determine the cause of the maximum, hence the need for parametric studies or optimisation runs. 
    • Yes the peak cooling load can be reduced by changing the any of the following examples (and surly more possibilities) window size, window type (U/SHGC) Insulation thickness, PCM type/position, orientation, lighting type.
    • The only way to use the output to determine what is the cause of the maximum is to have the maximum reported to csv as a single annual output- hence the entire premise of this Post (I guess you missed the point?)

    Thanks for your response- I enjoy the way you cause me to explain in detail the problem space, and do learn form our conversations (as I hope you do as well)

    Best-







    Jeremiah D. Crossett  | Senior Analyst  |  Phase Change Energy Solutions
    120 E. Pritchard St.  | Asheboro, NC 27203  | Mobile 503-688-8951
     

      






    On Tue, Sep 18, 2012 at 10:58 AM, YuanLu Li <yli006@xxxxxxxxxxx> wrote:
     


    See my comments below.
     
    No need to reply to my comments, as there are enough said on this topic..
     
     Dr. Li  

     
    To: EnergyPlus_Support@xxxxxxxxxxxxxxx
    From: jcrossett@xxxxxxxxxxxxxxx
    Date: Mon, 17 Sep 2012 16:49:17 -0700
    Subject: Re: [EnergyPlus_Support] Annual Peak cooling variable ?

     
    Bent & Linda Thanks-  Could I ask if this feature could be considered for any version of E+, and if you can understand why it would be left out of version 1?
     
    No one, except you, would ask  for the max peak value, to be displayed as a separate variable and cannot get it from the spread sheet yourself. 
     
    A simple program would extract the time and values from the ESO file, and give you an output, variable name, value min at time min, value max at time max..May be not simple, if you only code using Microsoft Visual series SDK.  I believe that the consol mode is still it there..

     I was thinking it would make a good replacement for the redundant "environment", "annual" and "Runperiod" options- and could be a simple change to have one "Annual" and add an option for "Annual Max" and an option for "Annual Min"..
     
    Annual max and annual min are EPW dependent data, and are already given in the .stat file.  Environment, annual and runPeriod has nothing to do with the max single peak value..

    • Prior to posting this searched documentation for readvarseso, read every page of documentation (1832 to 1834 input output manual and pages 34 to 36 of "tips and tricks" and page 206 of "axillary programs")  I do not see any documentation as to how one would attain the information from readvarseso that is not contained in the Input Data Dictionary.   If there is a way to use .RVI files, or to set the IDF to report the maximal value, or to use get the maximum data out of the .ESO files that would be great. 
    • The csvproc program runs statistics on hourly values, where I am looking to use .RVI file for annual values so this does not appear to be of any use. 

    I spent three days on this before I posted, and I have read all documentation I could think of, but will go-ahead and look some more considering you are saying that this is possible and documented. (any advise where to look?)
    The ReadVarsESO.exe file is in the PostProcessor folder.  There is also a batch file example there.
     
    There is a number of exercise for you to do in the AdvancedOutput folder of the exampleFiles folder.  The instructin is in ExerciseOutput1 Instructions.pdf.
     
    After you have used the .rvi file to select the required variable to the .csv file, click on the cloumn and ask the spread sheet to show the max and min value.  It will be a waste of resources to create these two values as  separate variables..
     
    This is not the first time that "how to use .rvi file" was asked in the forum.  The variable names in the .rvi file are those in the header of the .eso file.  If the variable is not in the Outpupt variable list, it will not be there.  If the variable name  is not in the .rdd file, it will not be generated during simulation.   This is why you cannot generate your own name with a "max" in it..


    Jeremiah D. Crossett  | Senior Analyst  |  Phase Change Energy Solutions
    120 E. Pritchard St.  | Asheboro, NC 27203  | Mobile 503-688-8951
     

      






    On Mon, Sep 17, 2012 at 3:49 PM, Linda Lawrie <linda@xxxxxxxxxxxxxx> wrote:
     


    At 04:25 PM 9/17/2012, Jeremiah Crossett wrote:
    The need for an object that can output the annual min/max loads to a simple single number that can be compared with other design iterations is common and should be considered for inclusion in Energy Plus V7.2.

    Will not happen for V7.2.

    • Are you saying that ReadVarsEso PostProsser is capable of producing CSV files with the peak value of sensible cooling rate by some undocumented method?

    The ReadVars is a very simple method of reading the .eso file.  Brent is saying that the .eso file contains the information you want.  (And, it is documented).

    Have you looked at the csvproc program?  I do not remember if that might help you or not.

    Linda

















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