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. (Actually, this happened after I deduced a Utility bill problem in EnergyPro for someone who I spoke with - and I've 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%)
Mar 21 2013
Energy-models.com is happy to announce that we are launching an energy-modeler directory. The best part is that the listings are free.
Fill out the form here
View the directory of the first 50 companies to sign up!
What does this do for you?
- Builds your Search Engine Rating in (Google, Yahoo, Bing, Yandex etc.)
- Helps new energy modelers find a local firm
- List your available services
- Reach new audiences
We will be launching a demo of the first companies to register soon!
The directory is already showing a good turnout. Thanks to all who have signed up already!
Mar 11 2013
Good old Daylight savings time is officially in play. For many of you reading this, you may never have heard of it, but it's something we do in much of the United States, Canada, and Europe, as well as other parts of the world. Basically, we move our clocks an hour forward for about half of the year.
The history of daylight savings time is actually pretty interesting, and recently, it was moved into March because it was deemed to save significant amounts of energy. (Culturally, more people stay up later than get up early, therefore - less lights are used!).
In any case, this reminded me of a common question: How do I model Daylight savings time in TRACE 700 or eQUEST
It's really easy!
To make the change in TRACE 700
- Go to the Actions Menu
- Select "Change Load Parameters"
- In the lower right, select the Daylight savings time period (this would be March-November for many regions).
- NOTE - the "Summer Period" is unrelated to daylight savings time, but it is easy to mistake. However, if you made the mistake of selecting March-November for the summer period, the impact would be minor!
To make the Change in eQUEST:
Daylight Savings time is automatically implemented in eQUEST. It is not sufficiently easy to change the exact months.
It is "On" by default, which works for much of eQUEST's market, but the large international audience may want to know how to turn it off:
- Go to the "Project and Site Module"
Feb 22 2013
So you want to model a heat pump in TRACE 700? And in reality, you have no backup heat... Or maybe you have backup heating, but you know it will never operate because you have an enormous geothermal well.
Regardless, of the scenario, there's a few key features to modeling heat pumps in TRACE 700. (There's probably several dozen main components - but lets look at a few tips).
Keys to Modeling a heat pump in TRACE 700:
1) Create a backup heating plant (this should actually be your first step). You should technically have 1 backup heat plant for each cooling plant (even if in reality - this never operates). Do not set the capacity to zero - regardless of what you have heard in the past. See, if you set it to zero, you'll have no good way to troubleshoot later.
2) Create your cooling plant as a heat pump plant. The key here is to set the heat source to the corresponding backup heat plant. Typically, keep the 'reject heat condenser heat to' the default field.
3) For the cooling plant, the cooling capacity and efficiency are important as normal, but the "heat recovery" capacity is actually the "heating mode" capacity, as well as the efficiency. The default value of 14.4 mbh/ton is actually a pretty good number, though it's often best to put in the exact capacity.
The rest depends on weather or not it's an air to air heat pump, a water source heat pump, or a VRF heat pump, and this topic could get rather lengthy.
The key part to understand is what happens with the coils:
Your system will have heating coils and cooling coils. The heating coils MUST be assigned to the backup heat source, and the cooling coils must be assigned to the heat pump cooling plant.
Feb 7 2013
By popular demand, we have released the 32 Tricks in TRACE 700 webinar as a standalone purchase. Order today, and you will get access to the video course for life (or until Earth freezes over).
To learn more and sign up for the course - Check it out here.
Watch the preview video there or check it out below:
Jan 23 2013
TRACE 700 is unique Building simulation software - Especially since it does both load calculations and energy modeling. There's a lot of people that use TRACE 700 to do a lot of different things: Load Design, LEED models, Life Cycle payback, just to name a few.
Did you know that TRACE 700 is over 2 million lines of Code? TRACE 700 is incredibly complex and has computational power that far exceeds anything you can do on a spreadsheet!
So, depending on your job title - you may or may not use certain features of the program. For example, maybe you need to interface with GLHE pro for sizing Geothermal wells (TRACE 700 can do this, and more!), but maybe you don't
In my travels, training at various places, I've found there are 7 basic things that all TRACE 700 users should know (but often don't). If you run into someone who claims to know TRACE, but doesn't know these 7 things - chances are they don't have as much experience with the program as they may claim!
7 - Limit file names to 15 Characters
If you've never heard of the 15 character limit, it's likely that you have never heard of archiving files (#5). You can't archive a file with a name over 15 characters. There's a long explanation to how important this is. But let's just say that long names (over 15 characters) lead to buggy files!
6 - Sort lists Alphanumerically
Did you know you can sort lists alphabetically in TRACE 700? So, when you click on your room dropdown menu - rooms are easy to find. You can do this by going to the options menu at the top of the screen and selecting "sort lists".
5 - What an Archive file is...
Jan 9 2013
I've never attempted a list of LEED approved software for LEED EAc1, and EAp2. I am sorry to omit anyone, but it's a common question.
First - There are a lot of software packages that can be used that are not mentioned explicitly (see "Other" in the list below)
Second - To give a simple answer to the question, LEEDonline does in fact have a list of common software programs (so it can tell you what reports to upload). Though it has been pointed out that LEED does not actually approve software, the actual software approval process is fairly complex, so the purpose here is to keep it simple.
List of approved LEED software
(Bold indicates it is mentioned within the LEEDonline v3 EAp2 forms)
- Visual DOE
- HAP (Carrier HAP)
- TRACE 700 (Trane TRACE)
- OTHER (see requirements of Appendix G, Section G2)
- BLAST (not mentioned within the LEED form, but listed in 90.1 section G2)
- IES (Integrated environmental solutions, listed in LEED Advanced energy modeling)
Please comment with other software that you have used for LEED certification for EAc1
Jan 8 2013
As energy modeling grows worldwide, the demand for international weather has grown. eQUEST - being so popular, has a lot of weather locations, but a modeler often needs more.
Energyplus has a large set of international weather, but it must be converted to .BIN format. This process is easy, but there is a slight glitch in the initial install. Check out this video to see how to convert and use energyplus weather files (epw files) in eQUEST.
The links mentioned in the video are listed below the video (don't forget to go fullscreen, and select HD)
A note on file paths
Also, please note that this was done with Windows 7 (we deliberately skipped file paths because they can be different on different operating systems, and custom installs)
Typically, the weather folder is located in C:\Users\Public\Documents\eQUEST 3-64 Data
Attn Advanced Users: The *.ini file is not difficult to adjust (just open it in wordpad/txt editor and you can edit paths). However, it's best to delete it first (because it is going to regenerate anyway), and you will then start with an "up to date" *.ini file.
Jan 3 2013
Okay, so you've got your building geometry setup, and now you are moving on to replacing the default construction types with your actual construction types (using actual roof, wall, window details).
You quickly notice that your software package does not have an input for stud type, nor any sort of inputs relating to joists/studs (this is true of many software packages).
So How do you model joist/framed walls or roofs (steel, wood, or otherwise)?
The most common answer is found in ASHRAE Standard 90.1, Appendix A.
Since many modeling programs can only models layers in 2 dimensions, the standard provides guidlines for this for roofs, walls and more. We will focus on an example of a Steel-Frame Wall.
Chiefly, you need to know the following:
- Stud distance (16 on center/24 on center)
- Depth of joist
- R-value of continuous insulation
Knowing these numbers, you can lookup Table A3.3 in ASHRAE std 90.1 (for steel-frame walls).
From the table, you can find the overall U-factor of the assembly (and your modeling program should have an input for this!).
WARNING: it is not always best practice to simply model the U-value
The U-value is important, but the mass of the materials is typically important too. Thus, it is a good idea to model layers that yield a similar U-value to the one in Table A3.3, and that also have a similar thermal mass. Given the example of steel joist walls, an example would be to have the following layers:
- Exterior layer (sometimes Air films need to be included)
- Gypsum board
- Gypsum board
Dec 19 2012
Many of you ask about trends in energy-modeling, or if energy-modeling is on the rise. For those who ask, you probably already know, and are just looking for confirmation. Yes, Energy-modeling is becoming more and more important for several reasons. You can see these reasons below, but first, let's validate the claim that energy-modeling is on the rise.
Proof of this, is that the latest ASHRAE Journal headlined "Energy-Modeling - Making Good Assumptions", in a very well written article on the topic. (Also, thanks for mentioning energy-models.com/forum!).
When ASHRAE does something, everybody else follows. Sure, we hear a lot about USGBC, GBCI, and LEED, and so on... BUT none of those organizations operate without ASHRAE (since they all cite ASHRAE literature). In actuality, Energy-modeling would not exist as we know it without ASHRAE, (they developed many of the algorithms and continue to do so).
Let's not forget ASHRAE President 2010-2011 (the late Lynn Bellenger - God bless her), had the motto of "Modeling a sustainable world", further indicating the importance of modeling to ASHRAE. (Especially since Lynn was considered perhaps one of the most important presidents of ASHRAE, being the first female president since the organization began 116 years earlier!). In fact, AIA (another huge organization) also jumped on board with their publication of an Energy-modeling design guide earlier this year.
Finally, consider that Energy-modeling headlined the latest article in the December 2012 ASHRAE Journal, it is obvious that energy-modeling remains important to ASHRAE, and the industry at large.