[Bldg-sim] Fw: Need help related to building energy simulation

Julien Marrec julien.marrec at gmail.com
Sat Feb 1 12:49:24 PST 2014


Syed,

If you want to model accurately you will need to get details on the
construction, the appliances, the lighting etc, in order to calculate the
cooling load of your building (= the heat that needs to be removed). This
is especially true considering what you want to model: this is not as
simple as having something that works full blast or doesn't work at all. By
shutting off the AC when no one is in the room, you'll allow the
temperature of the space to go up, which means next time you turn it on
you'll have some extra load to remove at first, and this is highly
dependent of the building construction.

If you don't want to create a detailed model, you could, as David
suggested, do it empirically. For example by choosing two similar rooms
(surface, orientation, but also how they are being used) and two exact AC
models and strap a meter to each one. Let it run for a week's time or so,
and then on only one of the two AC put your occupancy sensor.

By the way, you don't have to model your entire campus. Depending on the
level of accuracy you're trying to reach, you could just model one room and
consider all exchange surfaces to be adiabatic except the external wall.

Good luck!


--
Julien Marrec, EBCP, BPI MFBA
Ingénieur en efficacité énergétique du bâtiment
T: +33 6 95 14 42 13
www.julienmarrec.com

DoYouBuzz : www.doyoubuzz.com/julien-marrec_1
LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr
LinkedIn (en) : www.linkedin.com/in/julienmarrec


2014-02-01 Syed aftab Rashid <saftab.rashid at yahoo.com>:

> Thank You David for your response
> Yes these are simple air conditioning systems. I want to do this analysis
> on My university building having about 250 offices and 400 Air
> conditioners. Basically what i need to do is calculate the energy or
> electricity usage of an air conditioner if it operates from 9 A.M. in the
> morning to 6 P.M. in the evening. I don't really want to get into much
> details of the building constructions etc.
>
> Actually i am building an occupancy detection system so i need to evaluate
> that system in terms of the energy that can be saved if Air conditioners
> are operated based on the occupancy schedules.
>
> You have mentioned 3 or 4 softwares which one of these can make me do this
> task easily. i don't have much time so i need some solution that is fast
> and appropriate.
>
>
>    On Saturday, February 1, 2014 11:59 PM, David Eldridge <
> DEldridge at grummanbutkus.com> wrote:
>    Syed, I wouldn't necessarily consider room air-conditioning systems to
> be "non-HVAC" - the last two letters stand for "air" and "conditioning"
> after all!
>
> But whatever we want to call it, you can certainly make a model for these
> types of systems in eQUEST, OpenStudio/EnergyPlus, etc. and other free and
> fee software packages.
>
> The bigger unknowns for you will probably how to model the buildings
> rather than the A/C systems, although you may also have some questions
> about the age and efficiency of the units that you are considering, if you
> are modeling typical existing units. Availability of data for new units of
> this type should be easier to acquire.
>
> Depending on what you are doing with the energy usage data that you
> collect, would it be possible for you to measure the electricity usage for
> some of these systems in your region instead of model them?
>
> Good luck!
>
> David
>
>
>
>
> David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, BEAP, HBDP
> *Grumman/Butkus Associates*
>
>
>
>
>  *From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
> bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Syed aftab Rashid
> *Sent:* Saturday, February 01, 2014 2:52 AM
> *To:* bldg-sim at lists.onebuilding.org
> *Subject:* [Bldg-sim] Fw: Need help related to building energy simulation
>
>
>      Hi everyone!
>
>  I am a masters student and doing my masters in electrical engineering. I
> am currently working on my thesis. My work in related to air conditioning
> systems in buildings (Non-HVAC) i.e. using the traditional stand alone air
> conditioners.
>
>  I need to calculate the energy usage of these traditional Air
> conditioning systems. can anyone suggest me how can i simulate it using any
> of the simple and free simulation software. Most of the software's i have
> seen on internet are build for HVAC systems but in my country HVAC system
> are still very rare so i have to give my analysis on Traditional Air
> Conditioning units.
>  looking forward to a promising response.
>
>  Thank You
>
>
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