Hello all,
I have a question about RESFEN that I'm hoping this list can help me get my head around. RESFEN is developed and maintained by LBNL and I believe runs off the DOE2 engine. The software is simple to use because of its limited inputs, however I want to change one of those restricted inputs.
I'm trying to change the boiler performance which I think I can do by editing the building description file (which RESFEN labels as a .d2 file). I've attached the file and saved it in a .txt format for all to see.
My question is: Can someone proficient in the DOE2 language help me decipher where and how to edit the efficiency of the boiler in the attached file? I don't know the part load, just that the boiler in question operates at 60% efficiency. If this is to broad a question please let me know and I will attempt to clarify.
Thanks in advance!
Alex Krickx
Alex,
With the caveat that I am not a programmer or a developer and with some
trepidation I will say I think I know where you should go at least. The
first part is a programming language, see above, but the last part looks
like DOE2 BDL. It is probably from DOE2.1e since it's from LBNL. So going
way back in the memory banks and scrolling down, down, and further down
there is something labeled:
##if #[Vintage[] eqs New ]
FHIR=1.3550 CEIR=.3703
##elseif #[Vintage[] eqs Exist ]
FHIR=1.5015 CEIR=.41667
I'm pretty sure that FHIR is what you want and if my memory serves, a big
if, it represents 1/eff so the first one, age New, would be 79.7%, and the
second one, age Exist, would be 66%. Since this kind of makes sense, I might
be right! If I'm not, hopefully someone who knows more will correct me.
Maybe you can verify this by changing it. I've never used RESFEN myself.
Let me know what happens.
Carol
Hi Carol,
Thanks for your response. Looking through the user manual, RESFEN is based on DOE2.1e (nice call!)
Resfen has 2 options to choose from: Gas Furnace+AC and Electric Heat Pump. From what I read online (http://windows.lbl.gov/software/resfen/faq/50_faq.htm#HVAC%20MODELING) RESFEN 5 does not model electric resistance heating, but rather models the buildings with a Furnace+AC system and then converts the energy consumption using expected heat pump performance to determine final electric consumption. I think what you came across is the conversion from the furnace system to the heat pump system. The website also takes into account the efficiency of the furnace as it reverse-engineers the expected heat pump consumption. The efficiencies are 70% for existing construction and 78% for new (which are similar to the numbers you came up with).
I may still be able to edit the piece of code that you describe but as I'm also neither a programmer or a developer it makes me a little nervous to do so.
In any case, thanks for your response and if I have any success I'll share it with the list.
Regards,
Alex Krickx
Alex -
Rather than trying to force RESFEN to model something that it is not
designed to do, I would suggest that you move to a more fully featured
simulation program.
Robin
*******
Robin Mitchell
I concur with Robin's suggestion.
Carol
Thank you Carol and Robin for your response. I wanted to know how far people had pushed the envelope in RESFEN.
With that said, what software do people use to model single family homes? I've used eQUEST for multi-family homes but not as often single family homes. What are people's thoughts on this?
Thanks!
Alex
Alex -
Energy 10 is a program that comes to mind for residential and small
commercial modeling, particularly if you are interested in modeling passive
solar features.
http://www.nrel.gov/buildings/energy10.html
http://www.sbicouncil.org/displaycommon.cfm?an=1
&subarticlenbr=112
Robin Mitchell