Energy Calculations

[classic]

Any body know how to do this? Please explain. Frank

[WHirsch]

"R" occupancies, or commercial? Prescriptive? Alternate method?

Start here http://www.leg.wa.gov/WAC/index.cfm?...&chapter=51-11

[classic]

Insulation, Windows, Doors, I think.

[Jorge Araya]

Hard to explain.
In California the "envelope" or "conditioned space" has to comply with requirements by the energy commission, you must know what the code says for your particular area, the process is very large and complicated, it involves the materials of the walls, insulation, ducts, duct sizing, a/c's and sizing, water heater, hydronic heat, furnaces, fenestration, exposure to the weather, latitudes, the times energy is used, lighting desing, quality insulation, and so on. there are computer programs designed to do this, once the building is calculated of course all the necessary input has to be done, then it gives you a report that can not be altered, edited, or text added, sort of .pdf file. this can then be exported directly into your drawings.

[Alex-Berkeley]

In California, the 1978 Warren Alquist act mandated a "performance" based energy code. Both the residential and non-residential energy standards all derive form life-cycle costing of envelope components, space heating equipment, water heaters, pumps, fans, lights,etc. Most residential energy compliance in California is done using state certified energy modeling programs - EnergyPro & Micropas (google these). Many other states, Oregon and Washington in my experience, also permit performance modeling but are more likely to use a variation of the Model Energy Code. All states are required to certify an energy code that is equivalent to or exceeds the MEC. There is compliance software available that I have used to provide energy code certification from Oregon, Washington, Nevada, and Massachusetts, but these are all based on simple heat gain/heat loss models and provide no tradeoffs for equipment efficiencies, shading, zoning, thermal mass, etc. in residential work the way the California performance programs do.
However, if you live and work in state with MEC-based compliance software, and you can use Chief Architect, you should be more than capable of downloading and using these simple (and mostly free) energy programs. Oh, a caveat, these programs are often not sufficient for calculating, let alone sizing, your HVAC systems.
Feel free to contact me for any more info ... and especially if you need guidance or doc.s for California's Title 24 (BEC Associates ... energy services since 1983.)

[zoome]

I use REScheck (formerly MECcheck) to do energy calculations. It is pretty stright forward ... and ... it's Free.

REScheck - Free Energy Code Software

Zoome

[RogerC]

In Canada all new homes will have to be Energuide rated by the year 2010. This is something like R-2000 but not as strict. Its a two day course put off by the Home Builders Assoc. Designers and Drafters are the logical people to do these calculations. Anyone who would like to add this service to their existing business should contact their local Assoc.

RogerC

[James Eggert]

I also use rescheck which is required when applying for a permit. This program basically determines you are within design parameters for a reasonably energy efficient home.

For final calculations for heating and cooling requirements leading to design, I use a dedicated program

http://www.hvac-calc.com

For those working with ICFs, this program deals with thermal mass characteristics which is why I bought it 4 years or more ago!

I thought I would add, Chief does not automatically plug in room sizes and wall areas and window and door sizes and U values. It's not designed to do that. This is a takeoff program which does the calcs for you based on your input and other discerning factors you wish to account for!

[Jorge Araya]

And just for the fun of it.
Here's a way to export energy calcs. to Chief from
"Energy pro" (registerd trademark of energysoft)
The program allows to send the files as blocks for ACAD,
but not for Chief, and allows you to print directly to a
printer, and one last resource is it allows you to copy
to the "windows clipboard".
Ok! for those of you who don't use photo editor software.
Open Energy Pro>File>open>(the file you need to export)>
file>export>copy to clipboard>(select the page number)>copy>
Ok!>open Paint>image>attributes>set units to inches>set width
and height(8.5X11)>Ok>edit>paste>save as>(save to your preferred
folder and give it a name plus a number if you have many pages)>
back to the export window>select the next page>copy>Ok>back to paint>
edit>paste>save as. repeat for all pages.
I prefer to save as .PNG seems better quality and less size.
open Chief>open layout>select your layout
page>file>import>image
.bmp etc..>find the folder where you save the report>select page one>
ok! we have the image>open it>resize to 8.5 width>(it will automatically
enter the other size>now we have the full size sheet in the drawing>position
the sheet accordingly>and repeat the process for the next pages.
Why did I post this?
Two reasons:
1- I did not know how to, and it took me a while to figure it out!
and they look very professional, clean.
2- If you have them made outside you can have the person preparing the report do all this for you and get them back as .png's so you can import them to
your layouts. (besides the hard copy).
3- I don't have a photo editor, paint has become a great tool for this job.

[thorn]

Thanks much for the tip. I seem to have to check the attributes in paint every time befor I paste, or I get a 4 inch space at the top. You too?

[Jorge Araya]

The attributes in paint will not reverse to the original settings once you have set the 8.5 X 11 make sure the inch box is selected and you should have pretty good reports

[taharvey]

I use energy-10. Very powerful, and easy to use. Good for conceptual design too, since it doesn't require a CAD plan, but uses a quick shoebox stand-in, which is sufficient to most residential and small commercial.

It runs a simulation on a years worth of weather data for the building area taking into account, heating, cooling, electrical loads, people heat loads, passive solar gains, daylighting, etc.

Though it is comprehensive, its easy and you can get a model created in <10 minutes, it then allows you to make energy efficient varients (change insulation, windows, duct type, thermal mass, etc) for comparisons. It will even do efficiency analysis of all the possible strategies and rank which one will give you the best cost/performance, savings, etc.

I also use RValCalc for assessing wall R values. Cause a 2X6 wall with R-19 insulation isn't R-19, its a lousy ~R11-12! (one reason I avoid stick framing)

Also Energy-10 calcs can be used for energystar certs.

[ARIANA'SDESIGN]

thank you for that great tip.

Arturo

[dcmcm5]

Some of the software mentioned, like ResCheck, are good but are for checking code compliance and are not for calculating loads for sizing HVAC systems. Most of the houses built have incorrectly sized HVAC systems. In fact, most are oversized and result in poor performance. With HVAC systems, bigger is not better.

Systems are required by most state energy codes to be sized to ACCA Manual J requirements. Some of the software previously mentioned calculate the loads to Manual J. I use Wrightsoft's Right Suite package. Keep in mind that the load calculation is only part of the final product. Once the load is determined, you have to use Manual D to size the duct system and Manual S to properly select the system. If you want to better understand how these all fit together, ACCA has produced Manual RS which does a pretty good job of laying out the entire process. If you need help with designing an HVAC system, let me know. I have ben trained on the process and am a licensed professional engineer. Sizing systems is something I offer.

Hope this helps.

[FWD]

Here in So Cal for the type of work I do(small homes/additions) actual calcs are usually not req. if less than 20% sf glazing to floor sf. We just fill out forms XACTO was kind enough to attach and size FAU by a quick formula of btu per sf and that's about it.