RE: [EnergyPlus_Support] Annual Peak cooling variable ?

[YuanLu Li <yli006@xxxxxxxxxxx>]

Hi, Jeremiah

Thank you for sending me the files for clarification.

I think, they have confirmed all my statements.  Some remarks below as well.

You may want to verify your construction with PCM using an adiabatic wall.  I do not think the PCM will work sandwiched in between insulations with no charge and disharge control.  You may have the control in another object    I have  not studied your file in detail.  The step change should be visible in the wall heat transfer curve.

I have not run the PCM examples in the exampleFiles folder.  A simple capacitor model would only cause a delay in wall or zone temperature change.  Ice has the heat  storage and release effect at 0°C.

 Dr. Li  


To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: jcrossett@xxxxxxxxxxxxxxx
Date: Wed, 19 Sep 2012 11:26:33 -0700
Subject: Re: [EnergyPlus_Support] Annual Peak cooling variable ?


Right- well what can I say but challenge you to show me how wrong I am/write you are by producing a single number output in csv format from the file using .RVI  (actually the issue here must be one of communication because if you understood what I was talking about I am sure you would see the value!) 
> eplusout.eso

> eplusout.csv
> Zone/Sys Sensible Cooling Rate,Max
> 0
>  

This is your request.  It is up to the EPlus development team to decide. 

Because the values are already in the ..zSz.csv file, which is smaller and easier to extract.  So, why making the live more difficult. If you have the parametric file name set up in a list, a loop can open the  zSz.csv, go to the last line - 2 and pick out the values, and append them to a new file in the format of your choice.

The peak values are automatically generated in the sizing file and no .RVI file is needed. 

The normal .csv file would only accept a single value data for each column.  Therefore, the peak value cannot be sent there.  You can ask the developer to change the averaged value to peak, then will also show automaatically in a annual listing.  May be be both as two single field data.
.

If you do not believe me try it- attached is the file I created for you (ddy only)- see if you can make the output variable match sensible the cooling load?  Imagine there are some thousands of similar files and your design goal is to minimize loads- 

You would need a common .csv file for the 100 plus run.  The .csv in one simulation will not show all the values.  The data you need are in two places, .ESO  and   ..zsz.csv automatically without making a output request.

Even if you have the value in the main .csv file, you will still need to collect them from 1000 plus .csv files.
Also attached is a file with an example of the component cost objects- separate subject but that would also be nice to export to csv for the same reason of needing to have thousands of simulation results in one sheet for quick comparison. 
Component cost is never an element in the EPlus simulation input.  Even in an manufacturing factory floor, it is not possible to get the component cost.  You can try contacting Carrier, Hitachi, or GE and find out whether they can provide you with the DX coil cost, even if it is a replacement  part for a current unit.

All the cost in the EPlus are fuel and electricity cost calculated from the demand, and adjusted for efficiency performance, schedules (Season,Off peak, etc.), different locations, etc.  They are there mainly for LEED certification.  They have nothing to do energy conservation design.


Jeremiah D. Crossett  | Senior Analyst  |  Phase Change Energy Solutions
120 E. Pritchard St.  | Asheboro, NC 27203  | Mobile 503-688-8951
<http://www.phasechange.com>www.phasechange.com 

  <http://i.imgur.com/Sldxf.jpg>





On Wed, Sep 19, 2012 at 10:41 AM, YuanLu Li <<mailto:yli006@xxxxxxxxxxx>yli006@xxxxxxxxxxx> wrote:
>  
> Sorry, Jeremiah
>  
> I think you are still going around ia a closed loop, repeating what you wanted, without actually understanding what the value of what you are asking for can do for you in your parametric study.
>  
> .   If the following two peak values are what you wanted to be in a .csv file, they are already there, in the ....sz.csv, the last four rows..
>  
> .
> 1. Average value is 368.89[W] Annual Average of all hours
2. Peak value is 1160.83[W] the date of August 21st Minute 16 minutes 53 seconds,
3. Minimum value is 7.74[W] the date of August 21st Minute 6 minutes 60 seconds.
> If you wanted to write an rvi file to extract this, it can be done, because the header field for 170 has 11 data values, and they are all there.
>  
> 3. and 4. seems to say that HVAC size is not the peak value, and there are better values. Do define them exactly what is actually needed for your parametric runs..
> .
>  
>> "5. the runtime Min and Max in the ESO have hour and minute of peaks associated with them so I do not think these are actually post processes."
>>  
> The time stamp is assotiated with the data value, when the values were stored.  That is why six registers are required to store the temp and maximum and minimum values with time stamps when writing a post-processing program to extract the data values.  Data are added to the .ESO file at run time.  To extract data from the .ESO file to meet your formatting requirement is a post-processing activity.

>  

>  

> You have added a few more items, such as Min+max reporting frequency, "cost per unit output capacity", SumOrAverage increments for the the component.  Because my standard of English is poor, I do not know what you are actually wanted.
>  
> Reporting frequency - Timestep, hourly, daily, weekly, monthly, annual.
> Cost per unit output capacity - tariff value.  Cost per watt?
> Last item, I really do not know what it is.
>  
> If fact all those items that I can understand are already in the EPlus reporting system.
>  
>  
>> "7. The reason I am surprised there is not a simple approach to account for HVAC size in csv format is that it is such commonly needed info and should be attainable with commonly used methods-- getting a peak value is just one way of approaching this. attainable.".
>  
> Sorry.  Does not make sense.  Why should the HVAC size in a .csv format? 
>  
> HVAC demand is  in .csv format to show the variation with weather conditions is always available.
>  
> Sorry.  I still do not think that you  understand what you are asking for.
>  
>  
>  
> Dr. Li  
> 
>  
> To: <mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: <mailto:jcrossett@xxxxxxxxxxxxxxx>jcrossett@xxxxxxxxxxxxxxx
> Date: Wed, 19 Sep 2012 06:30:46 -0700
> Subject: Re: [EnergyPlus_Support] Annual Peak cooling variable ?
> 
>  
Dr LI,
I make no claims to be more of an expert than yourself, just that you where making many assumptions that did not seem to fall within your personal area of expertise. You have much more experience than I do, but even the best make a mistake from time to time if they are not careful. Today I am glad to see your response and you are correct in what you have said below- Still I have some points to make myself with regards to your comments.
1. The reason to have it in the RDD- then it would be accessible with use of .RVI file (this would make it work with the current methods such as jE+ and Genopt and Batch Mode.
2. The cost of HVAC is associated to size, size associated to Max value.
3. The Max value is not the actual HVAC size, but correlates nicely.
4. It would be better to have the calculated design load, but a peak annual value would correlate much better than the current annual averaged value that does not correlate at all.
5. the runtime Min and Max in the ESO have hour and minute of peaks associated with them so I do not think these are actually post processes. 
6. The concept to use this in E+ is simple, it could be accomplished in a few ways-- the first option could be to add MIN+MAX reporting frequencies or the second option could be add one additional output variable call it- "Sensible cooling rate Peak", or the third option would be to produce output variables in SumOrAverage increments for the the component cost line item section and then could use the "cost per unit output capacity". 
7. The reason I am surprised there is not a simple approach to account for HVAC size in csv format is that it is such commonly needed info and should be attainable with commonly used methods-- getting a peak value is just one way of approaching this. attainable.
8. I hope this makes more since now?
> 
> Jeremiah D. Crossett  | Senior Analyst  |  Phase Change Energy Solutions
120 E. Pritchard St.  | Asheboro, NC 27203  | Mobile 503-688-8951
<http://www.phasechange.com>www.phasechange.com 

>   
> 
> 
> 
> 
> 
> On Wed, Sep 19, 2012 at 5:30 AM, YuanLu Li <<mailto:yli006@xxxxxxxxxxx>yli006@xxxxxxxxxxx> wrote:
>>  
>> 
>> I am only commenting on facts, most of the time.  If I am not sure, I usually ask for more information.
>>  
>> In your case, a lot of things still does not make sense to me.  That is why I only comments on part of your pose.  So if you disagree, just agree to differ.
>>  
>> For example, you suddenly raised "Initial cost", etc.  They are not in your simulation.  So how do you optimize.  For equipment, simply call a tender and pass the problem to the manufacturer or vandors.  I have done that many times.  You will collect lots of date from one of these exercises.  You are ar the vendor end, and have to do all the hard work.
>>  
>> It is fine to claim that you know more real situation then me.  I do not know how many countries you have travel to, and how many HVAC systems you have worked, on and how many PCM you have tested.  
>>  
>>  Min and max is a post-processing operation.  It does not involves the .IDD.  You can get the max and min from the ESO, if you have loaded into it, and add a small routine to add the values at the bottom of the .csv as in the sz.csv.  If you are nodule developer, you can add that in yoursell and compile it for your own use.
>>  
>> I never ask for the max and min as you do it in your parametric runs.  Because the decision link algorithm does not use the max and min value of every data.  The algorithm for ASHRAE model  is minimum HVAC for maximum comfort.  You have implied that but I do not think that they are  in your parametry runs. 
>>  
>> My program will look for the condition of the solar position and look around the noon period, when the economiy cycle is not available, and find the maximum load.  The building is modified and then try again.  Therefore the maximum peak value is never used.
>>  
>> Look at windows for radiation load, walls for both radiation and convection, etc.  Where does not annual maximum peak load fit in? 
>>  
>> So far I have not seen any response saying that the maximum peak annual load should be an additional variable in the .RDD.  I do not think you know which load you are talking about.
>>  
>> I did not say that you are wrong in asking.  But, if you read through what I said, you will find that your demands are not precise or accurate or how to impliment in EPlus readily.
>>  
>>  Dr. Li  
>> 
>>  
>> To: <mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx
>> From: <mailto:jcrossett@xxxxxxxxxxxxxxx>jcrossett@xxxxxxxxxxxxxxx
>> Date: Tue, 18 Sep 2012 18:16:19 -0700
>> Subject: Re: [EnergyPlus_Support] Annual Peak cooling variable ?
>> 
>>  
Li, Don't take this the wrong way- as I have eminence respect for your advise to me and others-- You do not have to be right all the time- and should make a point to fully understand the problem before you speak down at people for actual real world issues that you do apparently not understand.
>> RE: The hourly average value is not useful to determine smallest system size- if an option was added to the idd and accessible from idf editor to output Min or Max than the problem would be solved and it would be useful for minimizing peak loads when performing  parametric/iterative simulations. Yes a script could also solve the same issue, but then every user would have to re-do the same work over and over- so it makes more since for the developers to add the functionality.
>> 
>> 
>> 
>> 
>> Jeremiah D. Crossett  | Senior Analyst  |  Phase Change Energy Solutions
120 E. Pritchard St.  | Asheboro, NC 27203  | Mobile 503-688-8951
<http://www.phasechange.com>www.phasechange.com 

>>   
>> 
>> 
>> 
>> 
>> 
>> On Tue, Sep 18, 2012 at 5:22 PM, Jeremiah Crossett <<mailto:jcrossett@xxxxxxxxxxxxxxx>jcrossett@xxxxxxxxxxxxxxx> wrote:
>>> The reason to add this as a feature is not for my project, but because it would be useful to be able to use the peak high/low values rather then annual hourly average for all users who do parametric or optimisation runs with objective functions of minimizing cooling or heating capacity.
>>> 
>>> 
>>> Jeremiah D. Crossett  | Senior Analyst  |  Phase Change Energy Solutions
120 E. Pritchard St.  | Asheboro, NC 27203  | Mobile 503-688-8951
<http://www.phasechange.com>www.phasechange.com 

>>>   
>>> 
>>> 
>>> 
>>> 
>>> 
>>> On Tue, Sep 18, 2012 at 5:20 PM, Jeremiah Crossett <<mailto:jcrossett@xxxxxxxxxxxxxxx>jcrossett@xxxxxxxxxxxxxxx> wrote:
>>>> You do realize that both Linda and Brent both already answered this post, and that they actually understood what the issue was and responded accordingly.
>>>> The HVAC size of 4000Btu/h is for each individual dorm room and the use of a Valance Unit ( <http://www.edwardsvalance.com/>http://www.edwardsvalance.com/ ;)
The goal of the study is to optimize the envelope to minimize cooling load so that it is close to or below this value.