[Equest-users] Modelling Heated Windows in eQuest

Thu Jul 30 11:57:59 PDT 2015

Further to that approach:  there exists an option under switchable glazing
to toggle glass properties via OA temperature.

I personally remain unconvinced of the science/marketing behind the
“effective” overall U-value brought about by a reflective film.  On a
conceptual level, I understand how taping aluminum foil to the outside of a
normal pane of glass, or replacing your glazing with a mirror, would help
bounce back radiative heat losses.  I remain skeptical of the notion this
can be equated to an overall effect on the *conductive* heat gains/losses
through a typical window.

As always, use your best judgement – your simulation outputs are only as
strong as your inputs!

~Nick

*NICK CATON, P.E.*
*Owner*

*Caton Energy Consulting*
  306 N Ferrel

  Olathe, KS  66061

  office:  785.410.3317

www.catonenergy.com

*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] *On
Behalf Of *David Berty
*Sent:* Thursday, July 30, 2015 11:32 AM
*To:* Hari Jammulamadaka; John Aulbach
*Cc:* equest-users at lists.onebuilding.org
*Subject:* Re: [Equest-users] Modelling Heated Windows in eQuest

It seems to me that the easiest manipulation would be to modify the windows
U-value. You are in essence saying that all or a portion of the heat
transfer of cold air in the winter would be cancelled by the coating. Then
you could add a false plug load to account for the electricity consumed.

David Berty, P.E.

Baseline Energy Consulting

317.220.9272

----- Reply message -----
From: "Hari Jammulamadaka" <hari.swarup at gmail.com>
To: "John Aulbach" <jra_sac at yahoo.com>
Cc: "equest-users at lists.onebuilding.org" <equest-users at lists.onebuilding.org
>
Subject: [Equest-users] Modelling Heated Windows in eQuest
Date: Wed, Jul 29, 2015 10:22 PM

Hello all,

Thank you so much for the valuable input. The windows wouldn't consume more
than 150W. They have some special coatings to reflect the heat off of the
inner surface of the outer window, thereby keeping most of the heat within,
and thus effecting having a much lower U value than passive windows (that's
what the manufacturer claims). I intend to model that, and then compare
that with an experimental setup to see what is really happening.

I'll look through the older treads attached to the mail, and see how
baseboard heating works for my setup.

Thank you all again!

Sincerely,
Hari

On Jul 29, 2015 11:11 AM, "John Aulbach" <jra_sac at yahoo.com> wrote:

Hari:

Could you possibly use Baseboard heating to simulate the heated windows?
Baseboards are usually under windows anyway to mitigate transmission loads.
Not sure how you measure the kBtu/kW of your windows, but you can translate
into the same heating capacity.

See if the offered eQuest controls for Baseboard satisfy your requirements
on the windows.

BASEBOARD-CTRL

Takes a code-word that specifies the control method for baseboard heating
in the zone. Defines the control method as THERMOSTATIC using HEAT-TEMP-SCH
as the setpoints, or OUTDOOR-RESET to allow BASEBOARD-SCH reset control.
This is a zone-level keyword for PLENUM-type zones; it allows "baseboards"
to be placed in plenums and allows the simulation of outside or space
temperature controlled heaters in the return air space. The plenum heater
is activated based on outside air temperature and reset schedule when it is
outside controlled. When it is space temperature controlled, and if the
interaction with the return air does not result in a temperature above the
scheduled value, the heater is turned on. In either case, the source of
energy input to the heater is defined by the specified or defaulted value
for BASEBOARD-SOURCE. See also BASEBOARD-CTRL, THROTTLING-RANGE and
BASEBOARD-RATING. Input for this keyword is the code-word that specifies
the method used for controlling the output of the baseboard heating element
in the zone.

THERMOSTATIC           Baseboard heating is controlled by a thermostat
located in the zone. The program assumes that the baseboards add heat as
required, up to their maximum capacity, to maintain zone air temperature
within the heating throttling range.If there is a heating load the
baseboards are sequenced on first. If the baseboards cannot meet the entire
heating load, heating from the zone's air system, if available, will then
be activated.

OUTDOOR-RESET         Baseboard heating is controlled by a thermostat
located outside the building. In this case the program assumes that the
baseboard heating output increases linearly as the outside air temperature
decreases. The linear function and the operating period are defined by
SYSTEM:BASEBOARD-SCH.

John R. Aulbach, PE

Los Angeles Ca

On Wednesday, July 29, 2015 6:49 AM, Hari Jammulamadaka <
hari.swarup at gmail.com> wrote:

Hello,

I am trying to model a building with heated windows (windows with heating
elements). The windows are not meant for comfort heating of the building.
Just localized heating for improving the comfort conditions in the
building. I have looked all over and couldn't find a way to model them. Can
someone suggest how I could go about this in eQuest?

Thank you.

Sincerely,

Hari

"Twenty years from now you will be more disappointed by the things that you
didn't do than by the ones you did do.  So throw off the bowlines.  Sail
away from the safe harbor.  Catch the trade winds in your sails.  Explore.
Dream.  Discover."  --Mark Twain

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