[Equest-users] Initial Temperatures

[Aaron Powers]

Hello Devin,

To the best of my knowledge, it's not possible to set the initial
temperatures in eQUEST/DOE2.2 (unless DOE2 ever becomes open source and you
want to recompile the Fortran :) ).  The method used by eQUEST is to assume
that at hour 1, all previous hour loads and heat gains are 0, so in essence
the initial temperatures are all 70 F for all zone and wall temperatures.
 It then iterates through the first 3 days a few times before starting the
full simulation (I can't remember the exact number of iterations or number
of days) using the results at the end of the 3 days as initial conditions at
day 1.  So the results you see on hour 1 of the hourly eQUEST reports are a
result of this.  This is a way to approximate realistic smooth initial
conditions.

I'm curious, are you finding that your finite-difference model only follows
the eQUEST results when you give then exactly the same initial temperatures?
 I've always found the RF/weight-factor method in eQUEST to be very stable
(possibly due to the linearization of radiation?), even if you give it crazy
initial conditions, the results correct themselves within a week or so.

Aaron


Is it possible to alter the initial temperatures before a simulation? If so,
where do I do this?  Thanks for any help.  I'll keep looking at manuals and
hope to find something.

-- 
Devin M. Rohan, LEED Green Associate
Purdue University
Civil/Architectural Engineering
drohan at purdue.edu
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