Robert Fassbender's blog

Chilled Beams vs High Performance VAV

Posted on: June 4, 2014

Hello Friends and simulators-

We get an awful lot of questions about modeling new systems, and rightly so. These often involve workarounds and many people do these workarounds differently. (Example, how do I model VRF in eQUEST?). 

What are some of these cool "new" systems:

  • Chilled Beams
  • Displacement Ventilation
  • Underfloor Air Distribution 

While all these systems have their own time and place, newer does not always mean better.
Before getting caught up in the hype of any new, flashy system, make sure that you don't disregard high performance technology in conventional systems (example high performance VAV). 

This is a great read, by an HVAC genius, John Murphy, PhD.

A building simulation can show wondrous results. When chilled beams were first implemented in TRACE 700, it was surprising to see that Active chilled beams saved little, or no energy over VAV systems. I dug into this myself and found that the much larger fan, when unloading as is typical in a VAV system uses less energy than the smaller fan that does not unload in an active chilled beam system. Who would've have guessed?! This is a perfect example of why energy simulation is needed. The results are often counter-intuitive.

Of course, there are places where chilled beams may be a better application, but a simple energy simulation may surprise you on the fan power consumed!

And By the way, TRACE 700 can model all of these flashy systems OOB (out of the box = no workarounds). So, if you would like to do some of these test runs, maybe give TRACE 700 a try.

Free New Course for Managers

Posted on: May 7, 2014

Attention MANAGERS and EMPLOYERS

You probably always hear about needing better software, and that may be true, but remember that faster cars require better drivers. The software is not the limiting factor. Not even close.

I know you are busy, so to move straight to the point: we have put together a free tutorial to help you hire quality energy-modelers, or which energy-modelers you should retain (who deserves a raise?)

In a nutshell, the course covers:

  • The 5 factors to evaluate in an applicant
  • 20 example interview questions to help evaluate these factors (with answers)
  • Red Flags to watch out for
  • Ingredients to build an awesome team
Now, this course is for managers and employers only. I would personally like to extend to everyone, but let's face it: what good are example questions if everyone has the answers?
The course is complete but there are a few things I would like to add to it. Thus, please join the group if you are interested!
Again, to sign up, please join this linkedin group. (which can be used to verify your status as a manager). 

Not Conditioned But Not Unconditioned in 90.1?

Posted on: January 14, 2014

Last week, we received two incredibly similar inquiries related to the ruling in ASHRAE 90.1 from table G3.1.1a that “All conditioned spaces in the proposed design shall be simulated as being both heated and cooled even if no heating or cooling system is to be installed.”

Here is a sample of the question we received:

I have a space in the proposed that is heated only. It has a peak heating load of 12 Btuh/SF, but the baseline peak is 20 Btuh/SF. In this climate zone, heating is defined as conditioned when the peak load is greater than 15 Btuh/sf. Since the proposed is not conditioned and the baseline is conditioned, do I treat the space as unconditioned, semi-heated, or conditioned? If it is conditioned, how do I proceed?

Response:

That's a funny issue. To be clear, I'm assuming you are using 90.1-2007. In terms of heating for your climate zone, conditioned is defined as >15 Btu/h·ft2. Semi-heated is always defined as >3.4 Btu/h·ft2. By the way, semi-heated = a minuscule amount of heating. I have scarcely seen or heard of semi-heated outside climate zones 1, 2, or 3. Of course, the setpoint could largely determine that.

Since you have mentioned 15 Btuh/sf, that means your model is in climate zone 4 or 5.

In any case, the conditioned vs unconditioned should be based on the proposed value, which in your case, is not conditioned nor is it unconditioned. Therefore it is semi-heated. However, because of the climate zone, it is very possible that any small changes will move you into the “conditioned” definition.

You have two choices:

Experimenting with LED's

Posted on: January 9, 2014

Over a year ago, I decided to give LED’s a whirl and the LED's decided to give me a headache. I decided that I could not make a verdict on the purchase until a year had passed. It's been over a year, so here goes:

First thing, I did not install them for interior lighting, but for exterior night-time lighting only. I’m sure many of you are aware that LED’s are more popular for exterior lighting than they are indoors. In my opinion, exterior lighting is one of the best places to get LEED points because of the undisputed energy savings, plus LED’s can easily meet the lighting pollution reduction SSc8.

In any, case - why’d I update to outdoor LED’s? Naturally, I am energy conscious, but the main reason is because the incandescents were suffering very short lifespans and there was difficulty when changing bulbs in the outdoor fixture. I'd have said, "Hell with it", but the lighting is required by all residences in my neighborhood.The incandescents were averaging a lifespan of less than 1 month. I didn't know why at first but I finally realized that the wind was rattling the fixture, breaking the filaments on my “long-life” candelabra incandescents which were about $1 each.

The Perfect Storm to go Green?

Posted on: December 16, 2013

I’d like to ask you the reader, what do you think I mean by the word ‘green’ in the title of this blog. I'd guess that most of you thought of multiple facets of green, but primarily thought of energy.

In the past decade, most conversations you have likely had about anything 'green' have had a large emphasis on energy. In some cases, it was probably the only topic in the conversation; energy consumption has become the cultural catch-all for being green. (even though energy consumption is only a piece of the green pie!)

Why has 'saving energy' become synonymous with “green”? This may sound like a trivial question but to put it in perspective, consider that twenty some years ago, the phrase ‘green’ was synonymous with “Don’t be a litterbug” and not using CFC’s. To say the least, perceptions have changed, and we have reached a perfect storm for promoting energy-efficiency. In my opinion, this perfect storm is a result of a number of socio-economic factors. Here are the top 3 on my list:

Know Energy-modeling? Prove it!

Posted on: November 27, 2013

A lot of you are awesome energy-modelers. Now you can prove it. Recently, we sent out a survey which a number of you had participated in. Enough of you asked about Userpoints and how to get them and what they do. We did some brainstorming and decided to revamp userpoints and make the process as simple as possible. A few weeks ago, the top users were basically 3 people, and everyone else was near a tie, we decided to reset the board!

What do your Userpoints do for you?

  • Earn a reputation as a great modeler

Who has the most points?

  • Points = equal power 

(for example, allowing you to edit other users’ posts, or create your own blog entries). 

How do you get userpoints?

  • It’s simple: Post on the forum and answer forum questions.
  • Vote on the best forum topics and replies

When others vote for your post or your answer, you get 1 point. If they vote your answer down, you lose 1 point

So give it a try! You’ll be helping the entire community and earning acknowledgement for helping others.

Impact of an Energy-modeler

Posted on: September 3, 2013

I saw this quote on a bumper sticker the other day: "A journey of a thousand miles starts with a single step" 

It's not a new quote to me but for some reason-perhaps because the weather was nearly 100 degrees (which is rare in Wisconsin)- I had a flashback to a Wednesday morning drive to work at Trane CDS, supporting TRACE 700 (it was a really hot summer)

At the time, I only had a month or so of experience and I remember having anxiety a few mornings on my way to work because I had realized that even though we did not make decisions for our customers, people were making BIG decisions based off of the energy-models that I had supported. I had yet to complete my Trane Graduate Training program, and while I was savvy enough to support TRACE 700, I wasn't fully educated on HVAC.

In fact, driving to work on that particular Wednesday, I was feeling sick to my stomach because I had ended up in some crazy LEED-triangle, where I was talking to a 3rd party LEED consulting team (specifically, their energy-modeler), and the Design Firm in isolated conversations, wherein I assumed a strict privacy policy.

When you talk on the phone a lot (especially when you're waiting for TRACE 700 files to calculate), small-talk happens. Being in the middle of this ongoing LEED triangle, I had become aware of a few things:

The Design firm had a history of bad customer service with a certain manufacturer - Company X - and therefore wouldn't 'spec' Company X. However, the LEED consultant, including the energy-modeler was advising the Design Firm to spec Company X's equipment because it had worked well in past projects (for multiple LEED credits, not just LEED EAp2/EAc1)

eQUEST software registration code?

Posted on: August 6, 2013

Just installed the full version of eQUEST, a free building simulation program and now it wants a registration code? No, you didn't accidentally download spyware. It's likely that you might not have correct permissions in Windows for the default install. You'll get a prompt that looks something like this:

equest Enter your software registration code

Don't bother entering your software registration code! This is indicative of a larger problem that needs a full solution.

To solve this error (takes 5-10 minutes)

  • Uninstall eQUEST
  • Right click the install for eQUEST and "Run as Administrator"
  • When prompted to see who the install is for, select "Just me"
That should solve the problem.
You might ask, "What was the problem?" Well, basically, the default install for eQUEST installs everything into your "public user" directory. Depending on your permissions (often determined by your IT deparment) you may not be able to install to this directory. Selecting "just me" tells eQUEST to install into your specific user directory, which most people have permissions to read/write to.
Installed an eQUEST update and getting this message? Make sure you are installing the update to the same location as you have eQUEST currently installed

Control the weather? Create or Edit weather files!

Posted on: July 29, 2013

With the addition of our new chat functionality, we have received a lot of feedback and learned that many of you want to control the weather.

We figured out how to control the weather - well at least in an energy-model. Per your feedback, we made it easy for you to edit or even create weather files (and do all of this entirely in Microsoft Excel).

Many of you have probably tried editing weather files - and you probably found that it would be easier to control the actual weather.

The folks here put our heads together, and with my ninja-like weather-editing skills, and with a little programming, we created a spreadsheet that makes it simple for you to import weather data, edit it, and then export the changes directly into a file that is immediately readable by TRACE 700 or EnergyPlus (Actually, the file is even readable by DOE2 when converted to BIN - which takes about 5 minutes) 

Click here to control the weather! (...virtually)

Matching Energy models to Utility Bills

Posted on: May 22, 2013

One of the most common complaints a client (or an energy modeler) vocalizes is that the energy model does not match up with the existing utility rates. 

It seems that no matter how much you explain that the % savings stays the same regardless of an exact match on utility bills - the client won't believe you, until he or she sees the utility bills matching with the energy model output.

I've heard this question a lot... That's probably an understatement. As a result, I found that I was able to solve mis-matched models based on a "gut feeling". However, one day I decided to write down my thought process to obtain this "gut feeling" and realized that there was a method I was using, based on seeing thousands of energy-models. (to be specific, this happened after I deduced a Utility bill problem in EnergyPro for someone with whom I had supported - and the funny part is that I have never even opened EnergyPro)

With my nerdy side emerging, I did what most engineers would do: I made a spreadsheet. I noted patterns between the month to month relationships of the energy-model vs. the actual utility bills.

The result I came up with is a 7 step approach to finding what you need to change in your Energy-model to help it match the existing utility bills. Now, it can't solve everything (2012 was an unusually WARM year - and thus can't match up with an energy model built with a standard TMY3 weather file). However, I tried the 7 step approach, and I got my model to match the 2012 utility bills anyway. (every month of gas & electric bills to match +/- 5%)

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