Wednesday, May 1, 2013

EnergyPlus version 8.0 Released!

For those of you who don't know, EnergyPlus version 8 was recently released and available for download at  I thought this would be a great opportunity to share a few experiences I have had with this amazing energy simulation engine.


EnergyPlus has been around for a while now.  I just did some quick research and found out it actually started being developed in 1996 and had its first released in 2001.  Needless to say it has been around for more than a decade, longer than my professional career...

Most people who aren't familiar with the software, don't realize that it is actually a calculation engine and not in the same categories as eQuest, EnergyPro or others which are really only graphical user interfaces.  EnergyPlus is the replacement or next generation of the DOE-2 and BLAST calculation engines.  Most are familiar with DOE-2 which has various versions and is used by a significant number of graphical user interfaces including eQuest, EnergyPro, Vasari (Autodesk) and many others.

Graphical user interfaces (GUIs) that use EnergyPlus as their calculation engine include DesignBuilder, AECOsim (Bentley Systems), Hevacomp (Bentley Systems), and a few others.  OpenStudio (NREL) and Simergy (LBNL) are the two GUIs developed by the DOE and free.

I have been actively using the EnergyPlus for about 4 years now (I can't remember if I started with verison 4 or 5... ) and am continually impressed with the capabilities of the software engine, the forward thinking development of the overall product and most importantly the interoperability and development capabilities.

The documentation is also outstanding...  and sometimes a little overwhelming.  There are thousands of pages of documentation and I have probably made it through 60% of them.  Not in one sitting... or in any particular order.  I have learned a great deal about energy modelling and system performance in general, just by reading the documentation pages.  If you are a serious modeler, or aspiring modeler... check it out.


To wrap up, I just wanted to add a little bit about some of the more common GUIs, add-ons and other tools I have used related to EnergyPlus:

EnergyPlus Weather Files - One of the most used sources of weather data for energy modelling...  but have you ever tried to open and read an .epw file?  It is not easy to immediately decipher what data is there, but I created an excel file that reads and graphs the data (a much lower grade version of Climate Consultant software).  If anyone wants it email me and I will send you a copy.

EnergyPlus Benchmark Files - These are great for quick benchmarking and tweaking of variables to determine relative changes in energy performance.  They are also referenced to ASHRAE 90.1 so you have a dependable/defendable benchmark model.

EnergyPlus Example File Generator - Great starting point for really quick and simplified models.  Easily accessible on the web.

Sample EnergyPlus Files - There is an enormous list of example files (more than 400) that come with the software install.  They are compiled in a spreadsheet that you can keyword search.  I usually use this to find a special system type, like say a fan powered VAV box and can strip out, copy and paste the code into whatever file I am working in.

Ecotect - I can't express enough how great of a tool this is.  I hope Autodesk keeps it around.  It is such an amazing conduit for software interoperability.  I have used Ecotect for generating EnergyPlus .idf files.  It isn't my "go-to" tool for geometry creation, but it allows you to do so many quick solar and energy analysis studies. I think I am going to do a whole separate post on how amazing Ecotect is...

OpenStudio - This is probably my "go-to" tool for geometry creation, importing and initial results viewing.  It has a Sketchup plug-in which is great for quick, simple geometry modifications.  There have also been some significant developments in the overall software that I have yet to explore including a SDK.  I plan on exploring this further very soon!

DesignBuilder - Probably the most well known EnergyPlus GUI with its first official release in 2005.  This software was originally developed in the UK and has been used as a compliance model there and other places.  I tried using Design Builder a few times on a trial basis and found it very useful for model generation and results viewing for simple models (compliance type) which is what I think it was originally intended for.  Then, for the detailed or more complex systems, I would take the idf generated by Design Builder and start modifying it to suit my specific needs.  I think it is a great "gateway" software for EnergyPlus users.  It lets you understand what the typical model inputs are and how those are used to generate an IDF.  It also has some decent results reviewing components.  But it does have a cost, and as a new business owner, sometimes that cost is not something that is easy to swallow.

Simergy - Similar to opening the EP Launch window and IDF editor of EnergyPlus for the first time and a lot of the new commercial software (IES-VE, AECOsim, etc.), the Simergy interface for me is a little scary.  Unfortunately I haven't had the time to really use this tool, but I have heard some positive feedback from some of my peers.  Another one I look forward to exploring more!

Title 24 Compliance - One last note.  I have heard rumors that EnergyPlus will be the simulation engine required for the 2013 California Energy Code Compliance.  The CEC and others are working on a strategy/framework for making it happen.  I hope to hear more soon!


I look forward to hearing feedback and recommendations from others!


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