Hi everyone!  

    I am learning TREAT, so perhaps this is too simple of a question for you guys but I am kind of stuck... when TREAT asked me about the building I choose attached, considering that one wall of the building is attached to the neighbor's house, but when I check walls, all of them are set up to the outside, and so far I have not found the way to change the setting for that attached wall. Just for me to learn, is that attached wall considered towards living space? -considering that there is a firewall separating both units. 

   Your help is greatly appreciated!

                                    Luis

Views: 216

Replies to This Discussion

Hi Luis,

This is a great question that points to a fundamental tenet of energy modeling: we don't worry about surfaces (walls, floors, etc.) where there's no energy transfer.  We assume that temperatures between adjacent units (or between conditioned bedrooms) are essentially the same, so UA∂T = 0 (the delta-T is zero), and there's no point in modeling the boundaries between them.

In other words, don't model walls between adjacent units, floors over conditioned spaces, ceilings under adjacent units, etc.  You've already discovered that TREAT doesn't give you the option to specify conditioned space adjacency. 

So, unlike detached single-family homes, that will have at minimum 4 walls, a floor, and a ceiling, attached units will often have fewer.  The most "minimal" case is an inside apartment unit on a middle floor, which might have only one surface, a wall, on the Walls/Surfaces screen.

I hope this helps clarify.  Remember, energy modeling is not the same as architectural modeling -- we don't need to worry about surfaces that are there for structural or aesthetic reasons, but that have no thermal transfer.

 - Ethan

Thanks for reply Ethan,  

    Just curious, exterior walls have negative energy transfer (energy loss), heat gain from sun exposure, wind, etc, so when modeled as adjacent to the outside, with the R value of all materials, there is a calculation of that lost energy. I am thinking that the firewall should be pretty energy neutral and so I was thinking it should be represented as wall adjacent to condition space; even though I understand that walls from inside the condition space are not modeled. But the other Townhouse is not part of this condition space....  maybe I am seeing this the wrong way...  hmmm, love building science!

              Luis

Exactly right, Luis.

The other unit is conditioned also, so there's negligible energy transfer between them, so the common walls don't provide a heating or cooling load, and there's no reason to enter them in the model.

And to simplify it, there's no way to enter them in TREAT.

If you created this model with the New Building Wizard, you probably have at least one wall that you just need to delete from the model -- the one that would have been adjacent to the other unit.

 - Ethan

Great Ethan!  

I am going to give it a try!!! I know that what you say makes sense... it just feel silly modeling 3 walls

I really appreciate your comments!

                      Luis 

RSS

Discussion Forum

Basic Heat loss information

Started by Luis Hernandez. Last reply by tedkidd Oct 30, 2014. 1 Reply

How to model a skylight

Started by Luis Hernandez. Last reply by Luis Hernandez Oct 16, 2014. 2 Replies

Modeling the apartment upstairs

Started by Luis Hernandez. Last reply by Ethan MacCormick Sep 26, 2014. 2 Replies

Modeling a Townhouse

Started by Luis Hernandez. Last reply by Luis Hernandez Jul 7, 2013. 4 Replies

Videos

  • Add Videos
  • View All

Latest Activity

Alana Barnett added a discussion to the group Energy Auditing Equipment for Sale, Trade or to Purchase
Thumbnail

Energy audit equipment -all very new

I have a FLIR infrared camera, E40bx. Only used a few times -box, camera, charger, it is all there,…See More
14 hours ago
Alana Barnett joined allen p tanner's group
Thumbnail

Energy Auditing Equipment for Sale, Trade or to Purchase

Discuss the pros and cons of the equipment you are interested in prior to purchase. Post equipment…See More
14 hours ago
Crosbey Archery posted a blog post
19 hours ago
Profile IconRon Sarrick and Alana Barnett joined Home Energy Pros
yesterday
Jim Fowler posted a discussion

TREAT modeling of mid-rise apartments low heating load

Does anyone have experience using TREAT to model mid-rise (3-story) apartment buildings with…See More
Friday
Peter Krych replied to Energy Wise Solutions's discussion What causes a temperature plane in a home
"I also should have asked where the furnace was located,basement,1st or 2nd floor. In any case the…"
Friday
Profile IconJim Fowler, Jennifer Flanagan, Debra Smit and 2 more joined Home Energy Pros
Friday
Eric Sperline added a discussion to the group Energy Auditing Equipment for Sale, Trade or to Purchase
Thumbnail

Wanted: Energy Auditing Equipment for sale

I am looking to buy a door frame panel that will accept a duct blaster fan.  I don't need the…See More
Friday

Home Energy Pros

Welcome to Home Energy Pros – the unique digital community by and for those who work in the home energy performance arena.

Home Energy Pros was founded by the developers of Home Energy Saver Pro (supported by the U.S. Department of Energy) and brought to you in partnership with Home Energy magazine.  Home Energy Pros is sponsored by the Better Buildings Residential Network. Please honor our Guidelines

© 2017   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service