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Gary,<br>
That "addition" and "multiplication" factor are more often used for
changing the units of an input rather than for defining equations
like the ones we are talking about. Set up TRNBuild so that you see
something like this:<br>
<br>
Input:<br>
1*CL_SET+0<br>
<br>
(you may also need to define a heating set point as well. It would
have the form: 1*HT_SET+0)<br>
<br>
Then go back to the TRNSYS Studio (ie save your work in TRNBuild and
exit back to the Studio). Right click on the building (Type56) and
select "update building variable list." Next, define a new equation
(select the menu item Assembly: Insert New Equation...). and define
equations for the heating and cooling set points as we've discussed
in previous emails.<br>
<br>
make a connection from the equation to the building and connect the
appropriate equation to the appropriate Type56 input (you should see
HT_SET and CL_SET among the list of Type56 inputs.<br>
<br>
A couple notes: you will also have to define the variable "occ" as
used in the equations using either another equation, a forcing
function, or one of the scheduling components in the TESS
Applications library.<br>
<br>
When you look at your heating and cooling demand that Type56
produces, be really careful because when you go through a step
change in set point (ie when the building becomes occupied, the
cooling system will turn on and it will have an instantaneous
infinite load on it. Type56 is simply going to report that infinite
load and it will be up to your system to figure out how to deal with
it. Normally when running simulations in this manner (ie in
calculating space loads) you get rid of all the temperature setbacks
and setups so as to avoid this problem.<br>
Best,<br>
David<br>
<br>
<br>
<br>
<div class="moz-cite-prefix">On 9/19/2012 11:01, KUM GARY wrote:<br>
</div>
<blockquote
cite="mid:CABZ-9hGkv24vMk_nYTH8BBht3nGDuycWA3=Lpzj_=evq8sGNDg@mail.gmail.com"
type="cite">David,<br>
<br>
I have try to define the cooling equation in TRNBUILD but
unfortunately, i am unable to do so as it only allow me to input a
constant after the addition(99*(1-occ)) which mean i can only
define as Tset_cool = 28*occ + constant value. How should i go
about to solve this? <br>
Pardon me as i am still new in the software.<br>
<br>
Thanks<br>
Gary<br>
<br>
<br>
<div class="gmail_quote">On Wed, Sep 19, 2012 at 10:26 PM, David
BRADLEY <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:d.bradley@tess-inc.com" target="_blank">d.bradley@tess-inc.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Gary,<br>
The equation that I wrote was for a heating set point
temperature and you are correct, when the building is
unoccupied, the temperature would be allowed to fall back to
12C.<br>
<br>
The cooling equation might be:<br>
<br>
Tset_cool = 28*occ + 99*(1-occ)<br>
<br>
In other words, define the cooling set point as an
arbitrarily high number that the building will never reach.
There are of course other ways of turning off the cooling
but this is effective in your situation.<br>
Best,<br>
David
<div>
<div class="h5"><br>
<br>
<br>
<div>On 9/18/2012 18:57, KUM GARY wrote:<br>
</div>
<blockquote type="cite">
<p>David,<br>
Thanks for your reply. From your equation, it seem
that during period of 0 occupancy, I would get a
temperature of 12 degree. But I would like the
cooling to be switched off when there is no
occupancy. So how should I go about defining the
equation?</p>
<p>Thanks<br>
Gary.</p>
<div class="gmail_quote">On Sep 19, 2012 4:00 AM,
"David BRADLEY" <<a moz-do-not-send="true"
href="mailto:d.bradley@tess-inc.com"
target="_blank">d.bradley@tess-inc.com</a>>
wrote:<br type="attribution">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Gary,<br>
Defining your setpoint as a SCHEDULE in
TRNBuild simply allows you to set a value that
depends upon the time of day. Defining your
setpoint using an INPUT allows you a good bit
more flexibility. You could define your equation
as follows:<br>
<br>
Tset_heat = 24*occ + 12*(1-occ)<br>
<br>
occ would have to be defined in another equation
or perhaps a Type14 forcing function to have a
value of 1 when the building is occupied and a 0
when it is not occupied.<br>
<br>
Best,<br>
David<br>
<br>
<br>
<br>
<div>On 9/17/2012 10:29, KUM GARY wrote:<br>
</div>
<blockquote type="cite">Hi,<br>
<br>
I trying to calculate the cooling demand of my
office building in TRNBUILD and would like the
cooling demand to response according to my
occupancy schedule(less cooling at night and
more cooling at day). I try to define the set
temp at the cooling type by i not sure which
one should i use (schedule or input?) And also
the equation behind it, because when i enter
like for instance <u>24degree(set temp)
*occupancy schedule+0</u>, i would get 0
degree when there is no occupancy. <br>
<br>
Appreciate your kind assistance on this<br>
<br>
Gary Kum<br>
<br>
<fieldset></fieldset>
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<pre cols="72">--
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI 53703 USA
P:<a moz-do-not-send="true" href="tel:%2B1.608.274.2577" value="+16082742577" target="_blank">+1.608.274.2577</a>
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<pre class="moz-signature" cols="72">--
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI 53703 USA
P:+1.608.274.2577
F:+1.608.278.1475
<a class="moz-txt-link-abbreviated" href="mailto:d.bradley@tess-inc.com">d.bradley@tess-inc.com</a>
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