Re: [EnergyPlus_Support] Re: Automatic operation venetian blinds energy consumption

It's a low rise residential building so ASHRAE 90.1 technically would not apply. But this is being obnoxious :-)

You are totally and completely right it is a small energy consumption and irrelevant per se. But as Paul Torcellini says design for zeb it is important to be preoccupied with details. Like smoke alarms. The question is there are a lot of irrelevant energy consumptions that all together turn out not so irrelevant.

The schedule is a problem. Users "spoil" building simulation with their "illogical" behavior :-).

Thank you so much for your help.

Miguel

From: "jeannieboef@xxxxxxxxx" <jeannieboef@xxxxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Cc: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Tuesday, August 27, 2013 3:36 AM
Subject: Re: [EnergyPlus_Support] Re: Automatic operation venetian blinds energy consumption

ASHRAE 90.1 would define this as an unregulated load (not regulated by the 90.1 standard to have minimum efficiency), meaning that in a baseline comparison study, both the proposed design and baseline models would use the same energy here.

If you consider the rest of an office space's unregulated (guessed) plug-loads, it would be between 5 - 9 W/m2 as a rough approximation. For a 25 m2 office that is at most 250 W. How many Watts is the rating on your motor? What fraction of the time will it be running at max rating? What is the standby Wattage?

And finally, what is that as a percent of the usual 250 W plug loads of example office? Consider that plugloads make up a certain fraction of total building energy consumption. As you say, the loads add up, but the % that they incorporate is small. Consider rather a more accurate user occupation schedule, if you want to increase the accuracy of your simulation, or use a more accurate infiltration modelling approach.

The biggest hitters are:

- occupation

- lights

- fabric (or envelope, including solar and infiltration)

The most accuracy should be attempted on these most critical componants.

The model will never copy real life. We can only aim to learn from it.

Mit freundlichen GrÃ¼Ã?en- Sent from my iPhone (excuse the brevity)

i. A.

Jean Marais

b.i.g. bechtold

Tel. +49 30 6706662-23

On 26.08.2013, at 21:13, "migueltgpacheco" <migueltgpacheco@xxxxxxxxx> wrote:

Jean

Thanks. However, when you say small amount of energy what range are you talking of? Do you have some reference with data on this? I mean, stand by energy consumption is small but when added is significant. So I am trying to pin down this small amount of energy with little success. The nominal power of the motor is not so small. Multiplied by many windows may be significant.

Miguel

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "jeannieboef@..." <jeannieboef@...> wrote:
>
> It will be a small amount of energy. You'll have to define a other
> equipment energy user with a design energy usage and figure out the
> standby loss energy usage as a fraction of that. Then create a
> fractional schedule to reflect this. Then write an EMS to monitor
> blind operation and use to sensor values to overwrite your
> otherequipment schedule using an actuator to suite.
>
> As a beginner who has never used EMS, this may take 3 days. As an
> expert, 15 minutes. It is a good excersize. Goodluck.
>
> Mit freundlichen GrÃ?Â¼Ã?en
> Sent from my iPhone (excuse the brevity)
>
> i. A.
> Jean Marais
> b.i.g. bechtold
> Tel. +49 30 6706662-23
>
> On 26.08.2013, at 17:08, "migueltgpacheco" <migueltgpacheco@...>
> wrote:
>
> > Hi List,
> >
> > I want to estimate the energy consumption of automated blinds. I
> > searched the group for this topic but I didn't find any reference to
> > it. This is important because I couldn't find either any report on
> > monitoring the energy consumption of blinds. I'm trying to model
> > zero energy and everything must be accounted.
> >
> > Energyplus allows a number of sophisticated options for blind
> > control.I am using BlockBeamSolar option for the ShadingControl
> > object. But there is no way to know the energy consumption the
> > automated operation of the blinds.
> >
> > I canÃ?Â´t use the nominal power of the blinds motor's for an estimate
> > because this would be far too high. The blinds I'm modeling, can ope
> > n or retract completely, besides varying the slat angle. Slat angle
> > variation must consume less energy that open or retract the blinds e
> > ntirely.
> >
> > Even if I know the energy consumption for changing angle slat, that
> > would not be enough. The blinds are sometimes idle and sometimes on.
> > I have doubts on which report I would use. There is no report that
> > tells when a motor is on.
> >
> > Thank you in advance,
> > Miguel Pacheco
> >
> >
>