Hi everyone,
I am modeling a cabin log that is heated by electric baseboards and a fireplace that is consistently used during cold weather.
How can I integrate the fireplace load to the model, what would be the approach?
Thanks for the help.
William G. Lopez, CEM
Hey William,
1. Pull a cutsheet on the fireplace in question to get the input
btu and heating btu incident on the space at full output. If it's not a
commercial gas/electric fireplace with a cutsheet, engineering-judgement
the sucker based on something roughly equivalent.
2. Define a schedule for the fireplace that matches your
definition of "consistently used during cold weather." Consider a
fractional schedule if it's not simply ON/OFF.
3. In detailed mode: Internal loads tab
4. Spreadsheet view, select "Internal Energy Sources"
5. Find the space with the fireplace
6. Define a new load starting with your custom schedule. Fill the
fields in as appropriate - pretty self-explanatory at this point.
Sensible ratio would be your BTU incident on the space over the gross
consumption.
7. Carry around a smug grin coz' now you're the smartest energy
modeler in the room!
Rock on,
NICK CATON, E.I.T.
PS: If you're dealing with a fancy commercial fireplace that includes
thermostat controls and/or circulating fans... you might be better off
defining a system like a unit heater... fill us in if that's the case.
NICK CATON, E.I.T.
Is this a wood fireplace? If so heat output will vary based on the type of wood, moisture content, and amount of fuel in the fire box. You'll also need to figure out where combustion air is coming from - the space or ducted from the outside.
Jon Bruneau, PE, LEED AP BD+C
William,
Model it as you would any other source BTU to the appropriate space(s).
Quantify and schedule the heat output throughout the hating season.
It's that simple if you know when it is used and how much heat it puts
out. Otherwise you must talk to the owner/occupant, or do some research
or some educated guesswork. It can make a big difference in the monthly
heating kWh.
Glenn
Nick,Jon,
It is a wood fireplace, the procedure described below is well detailed, I just have a doubt on the line 6, what would be the source type required by the spreadsheet?
Thanks for your time
It is greatly appreciated
William
William,
Your options are gas, electric, hot-water, and process. Here's the
definition of process in the help files:
The load will not contribute a utility load. Examples of this type of
load are gasoline-powered fork trucks, oxyacetelyne welders, wood
stoves, and bottled gas equipment. Sum all the process loads in the
space and express the total with the keyword SOURCE-POWER. The portion
of the total process load that enters as a heating or cooling load is
specified with the SOURCE-LATENT and SOURCE-SENSIBLE keywords.
So a wood fireplace would be a process load ;).
NICK CATON, E.I.T.