Michael OKeefe's profile - activity

I would open the modified *.epw file in a text editor and confirm that the numbers you see in Elements are the same numb

The methodology for how Elements keeps the Global, Beam, and Diffuse components of solar radiation in balance is written

Others can jump in here but the sources for the EPW definition that I am aware of would consist of: The technical pape

Others can jump in here but the sources for the EPW definition that I am aware of would consist of: The technical pape

Elements 1.0.6 and below saves modified EPW files using a "line-feed" line ending. However, we have heard in the past th

This is an excellent response. Thank you @sashadf1. @Frank Wang, does your Excel use a "." as the decimal separator? Unf

Can you confirm that the values look as expected after you paste them into Elements? Elements allows you to click on the

Elements does not split global solar radiation into direct (normal) and diffuse, it only relates those three metrics. Th

Elements does not split global solar radiation into direct (normal) and diffuse, it only relates those three metrics. Th

I'm wondering if saving to the text-based *.FMT type from Elements would help clarify what's going on -- it's still a bi

Thanks for your question! Can you please send your file to elements@bigladdersoftware.com so we can better understand wh

I'm a bit tied up with other things this week but always feel free to contact us at Big Ladder with the Elements/epw fil

I've got another project I need to wrap up ASAP but feel free to contact us at Big Ladder with the epw file you created.

If you need specific and detailed help with Elements, feel free to email the support email (at the same page where you download elements from).

Elements is a little bit different from a regular spreadsheet in that it enforces relationships between variables and never allows you to have an inconsistent psychrometric or solar state point. Because of this, some care is required in the order of operations when changing weather file data.

With regard to pasting data into the cells, there are some known issues when a number that uses a "," as the decimal separator is used or when any value that can not be parsed by a number is used. Be sure to check your source dry bulb data and try pasting one, or a few, at a time to confirm everything works, OK. Be sure to use the latest version of Elements as we periodically release new versions with bug fixes.

Data such as azimuth angles are tied to the location -- to change those angles, you must set the location correctly in the header data. Starting with an existing file or using the "new file" should both work but be sure you set the "Value to Hold Constant" to something sensible when pasting your data.

If you have specific questions or problems, feel free to email Elements support directly.

(In full disclosure, I am the primary developers of Elements)

There is interest both internally and externally to have Elements do something like this but unfortunately it is a GUI tool only at this moment...

You could try separating the top of the EPW from the time series data and process the time series data in Excel and then paste them back together.

As of this time, you can't add columns to an ELEMENTS file over and above what we offer from the GUI. However, you can always save the EPW and load it in Excel (as comma separated variable) and directly modify the appropriate columns. See the documentation on the EPW file format for details on which column is which: http://bigladdersoftware.com/epx/docs...

I was privileged to be able to participate in a great panel discussion at IBPSA-Chicago yesterday on weather. You might be interested to watch Joe Huang's presentation (2nd one) as he discusses some of the models he uses to determine solar data: https://vimeo.com/152621017

Unfortunately, at this time, we don't do anything special in Elements to support .ddy files.

Some things to check: be sure you have the correct latitude and longitudes set (be especially careful to get the sign correct on west longitude -- open a known good EPW file near your area to double check). Be sure the "variables to hold constant" make sense. Feel free to contact us from the support email on the Elements home page if it's still not working for you and we can discuss more.

I'm not sure how well this will work for you but one possibility is to use the Elements weather file converter/editor.

Although Elements does not (yet) have a direct CSV import/export, one possible thing you could do is to create a new (blank) weather file in Elements.

You can start by editing the header information to match the target site (it's important to do this first before you try to paste solar data).

Then, column by column, cut and paste your CSV data onto that blank file. You'd have to take care to work with the "Variables to Hold Constant" pull-down within Elements as you cut and paste so as not to mess up previous data you've pasted in already.

See the Elements documentation for more details. You can use the Add/Remove columns button to display fields that aren't shown by default.

There is a tutorial along these lines here.

With regard to solar data, there is another question here on UnmetHours that helped a user deal with cutting and pasting solar data updates into Elements.

It's all still a quite manual and a bit messy but could be faster than trying to figure out the EnergyPlus Weather Converter tool if you're only planning on building a couple of weather files.

In the interest of full disclosure, I helped build Elements, so I may be biased here.

Best of luck!

If your overall objective is to modify an EPW file, one possibility that might be easier is to work with is to use the Elements weather file processor. As a disclaimer, I am one of the developers of Elements. Elements is free and open-source software.

The tool allows you to directly open an EPW file, make your changes, and save the file again.

You can find more information here:

http://bigladdersoftware.com/projects...

Hope that helps.

This is probably related to a known issue in Elements 1.0.4. We will be releasing 1.0.5 very soon and that should fix this issue -- sorry, for any problems this may be causing you.

Yes, you are correct that Elements enforces an equational relationship between the various weather variable attributes. This can cause some challenges when adding new information -- I suggest an approach below.

First, let me mention the equation relationship as follows:

Z = the hourly averaged zenith angle in radians

Global Solar = total irradiation on a horizontal surface

Diffuse Solar = diffuse irradiation on a horizontal surface

Normal Solar = beam normal irradiation, yes, this is "Direct normal Radiation"

These are related as follows:

GlobalSolar = NormalSolar * Cos(Z) + DiffuseSolar

Note that the cosine of the zenith angle (Z) depends on your latitude and longitude so before doing any solar editing, make sure you have set the proper location and time zone in the header.

Elements currently enforces this relationship even when cutting and pasting. You can pull up the "Cosine of Zenith" as another column ("Columns: ADD" at bottom left) and also the Solar Hour Angle for reference (0 is solar noon; +/- 180 is midnight).

If you want to paste in new global solar values from Excel, probably the best way to do it is to select the DiffuseSolar column and scale by "0" to reset the values to 0 (holding Normal Solar constant). Then Scale NormalSolar with a scale factor of "0" holding DiffuseSolar constant. This should "zero out" your solar variables. Then, when you paste into GlobalSolar (holding NormalSolar constant), the values you paste in should "take". If you have your own information for the beam normal and diffuse split, you can alternately paste those in and Elements will add up the GlobalSolar based on the above relationship.

In summary, when using Elements to add solar data:

1. set your correct timezone, latitude, and longitude in the header
2. select the diffuse column holding normal constant and scale by 0
3. select the normal solar column holding diffuse constant and scale by 0
4. paste the normal solar data in holding diffuse constant
5. paste the global solar data in holding normal constant (note: there will be a slight lag on this step as Elements has to inverse solve for each point)

Hope this helps.

We just confirmed this copy/paste issue from another user. One way to recreate this is to open an EPW file, start a new Elements file, then try to copy data from the EPW file (in Elements) to the new Elements document -- this doesn't work.

One possible work-around for the copy/paste issue is to work directly on the Elements file itself. If you start a new Elements file (or open an EPW format) and save that file as *.elements format, you can click on the *.elements file and rename the extension to "zip". After you unzip the zip archive, inside you will find two files -- one for header fields and another for time-series fields. You can directly edit those files with a spreadsheet program such as MS Excel. If you want to load that file back into elements, just reverse the process: close the csv files and rezip the folder and change the zip archive extension back to "elements".

There is a little bit more about the Elements file format here:

http://bigladdersoftware.com/projects...

I know Big Ladder hopes to release an update to Elements in the future and this issue has been added to the bug reports list as an open issue to fix at that time. Thank you for trying Elements and for taking the time to report this issue.