Dear Tommy,
I suspect that the only downsides to EnergyPlus are:
1. It almost certainly runs slower than EnergyPro / DOE
2. There is a fairly steep learning curve to any sophisticated software
The speed of simulations is gradually getting better and there are an assortment of tips and tricks to help your simulations run faster. I suspect that you can continue doing early design modeling with Energy Pro, and that the final EnergyPlus model won’t differ dramatically. You may also want to re-think the design process so that your parametric evaluations can be done separately from a meeting. There are also parametric tools available from several sources that work with E+; you might investigate those.
The learning curve has been shortened with dramatic GUI improvement in the last few years, but it’s still substantial and I doubt there’s a way around it.
Governments tend toward “solutions” that are not fully appreciative of the people and businesses they impact � no big surprise there. I rather wonder why thhey pulled the trigger when one of E+’s big advantages (modeling some of the complex, newer systems) is not even available due to the CBECC-COM limitations. There’s a tech committee somewhere in Sacramento that you should talk to!
My opinion, though, is that the assumption that a project’s financial success can be based totally on specific energy performance, is a little crazy. What if you discover an input error that affects results adversely? Does your client want the truth or do they want to game the system? Incentives, for example, are not normally “Take it or leave it”; they’re proportional to savings. A few percentage points either way should not affect the grand total much.
Designing thoughtfully and well is one thing. Thinking that ANY modeling program can duplicate the design’s performance is unrealistic. Even simple systems have thousands of variables, and complex systems are worse. I have a colleague who recently gave a talk called “After the Plaque” in which he described some of the many issues needed to properly fine-tune a facility AFTER they received a LEED plaque for a complex facility. Far better, I think, to spend time and energy doing M&V than to expect “perfect” modeling results. The incentives can be substantial for some projects, but the life-cycle savings for actual savings will be much greater!
James V Dirkes II, PE, BEMP, LEED AP
www.buildingperformanceteam.com
Energy Analysis, Commissioning & Training Services
1631 Acacia Drive, Grand Rapids, MI 49504 USA
616 450 8653
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: Monday, August 18, 2014 12:29 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Mandating EnergyPlus: Is it the right tool for energy code compliance?
Good evening from sunny CA. I am new to the forum and freely admit to being in over my head but have taken encouragement from reading through the past few years of posts and seeing newbies become active contributors, especially the repsonse from Nick Caton to Jeremiah Crosset in May of 2012...I forwarded the exchange to everyone in my office... we get few pearls of wisdom freely handed out. So..thanks!
To my question -
On July 1, 2014, California mandated that EnergyPlus be used for our state's energy code (Title 24) compliance. The switch was flipped and we are no longer allowed to use the DOE-2 program most of us had been using (EnergyPro). I am doing as much research as I can but am realizing that perhaps my modeling days are over - and while I am not that old and I am computer literate; I don't know CAD, SketchUp or OpenStudio all that well..and that's OK by me . Modeling was just something I did to suppport my diagnostic testing habit. As I have scoured the internets for training, tips and what-not-to-do's I found this forum and hope that you can offer your opinion.
Is EnergyPlus the right tool for Statewide code compliance? I understand it's an awesome and powerful program, capable of modeling advanced technologies, but is it the right tool for the market? The market being contractors and developers who just want compliance? The run times have been over an hour at times and these aren't extremely complicated multifamily projects - I see horror stories on here about a 300 zone supermarket that took 12 hours to run. Another factor mucks it up as well -
- CA now mandates an integrated design meeting. No problem we've been doing them for a while - but it normally involves me running numerous iterations while I am sitting at the big table with the design team. These are for above-code projects so accuracy in predicting the % over code is paramount..absolutely paramount. as often tax credits and incentives are on the line which means so is my job, backside and reputation if I get it wrong ( not saying the software I am using is accurate - but it's apples to apples) How do I explian to anyone that I've pressed calculate and now we must wait and wait? and........... by the way in CA we cannot yet model below-grade walls or solar thermal, chilled beams or VRF etc, etc (CA has a twist to the E+ interface called CBECC-COM to meet our code and the software code has yet to be written for these things) From the help desk: There is no formally approved workflow for modeling VRF systems in CBECC-Com. We are currently pursuing additional funding that will enable us to include these systems in a future version of CBECC-Com.
So... I am asking the professionals: is EnergyPlus the right tool for the job? or should I be justifiably peeved that it feels like I've been forced to ditch my 60 Mbps connection for a 14k Dial-up modem?
Your help is greatly appreciated.
Tommy Young
CEO
CEPE, HERS I-II Consultant
2701 Cottage Way, Suite 9
Sacramento, CA 95825
ph: 916.739.9750 ext 304
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Posted by: Jim Dirkes <jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
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