Re: [EnergyPlus_Support] Provocation about component loads

["Emanuel Sá" <sa.emanuel@xxxxxxxxx>]

Dear all

I'm writing just to say that I totally agree with this post.
One major aspect in the building design is to avoid loads! The efficiency of
a system is only important after you minimise the heating, cooling and
artificial lighting demand. To do that we need to have information that
could enable a deeper analysis of the whole system (envelope+air
tightness+windows+thermal mass...etc). If we want to go further on the
building energy efficiency improvement, we must start by its physical
analysis. So, my suggestion is that the reports related with the components
loads become easier  to obtain (maybe using a Report:Table:Predefined).

Best Regards

Emanuel Sá



2007/5/24, Clarice Bleil de Souza claricebleil@xxxxxxxxxxxx:
>
>   Hi all,
>
> I decided to join the discussion about the components loads because I am
> one of the people that frequently ask questions on the matter.
>
> I don't know about the others, but because my background is architecture I
> am interested more than anything else in the building performance. I
> understand the zone/sys cooling/heating load as an overall result of the
> interactions between the building, the occupancy and the system. It is very
> useful to a system engineer to size and optimize the machine but when you
> are working on the buliding level I am not so sure if this variable alone is
> enough to understand what is happenning.
>
> Once we are building designers we are after output variables that would
> give us some indications about where to act in the building in order to make
> it respond better to the weather and the occupancy. That is why some
> software developed to be used mainly by architects like Ecotect provide
> output variables for the component loads.
>
> You may argue that the interactions are too complicated to be splitted,
> that you should let EPlus work on them for you and that the best approach to
> the problem would be to do lots of parametric simulations and output them in
> a database in order to check the overall impact of each parameter in the
> cooling/heating load. That might be a potential approach but I see 2
> problems about it:
> - in practice it is too time and processing consuming;
> - what would be the best way to analyse thousands of results? I.e. you
> produce lots of information but how do you attribute meaning to it? I saw
> some strategies like datamining, statistic analysis, etc. used to deal with
> the problem ... and I keep wondering why to go there instead of trying to
> deeply understand the building physics, i.e. if you are modelling all the
> interactions why not try to see them in a way that could potentially short
> cut the process?
>
> By studying the heat balance algorithm I understood that this might be
> possible once you analyse the components of the air heat balance and the
> components of the inside surface heat balance. The way the building fabric
> will interacts with the inside air is through the convective heat transfer
> from surfaces and it would be very very useful to have this variable as an
> output for each zone.
>
> But apart from that, if it is clear for the designers that what
> contributes to this convective component are the radiant (internal radiant
> heat gains, internal visible heat gains, radiant heat exchanges between
> internal surfaces, transmitted solar energy) and conductive (opaque inside
> surface heat gains and losses) heat exchanges at an inside surface level,
> than plotting those components individually would be useful to evaluate how
> the fabric is affecting the convective heat exchanges from the inside
> surfaces to the air. I am currently working on a conference paper on the
> matter and would be very happy to discuss it further with the simulation
> community.
>
> I am sorry to be so nosy but I think it is worth the provocation.
>
> Best regards,
>
> Clarice
>
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>
> [Non-text portions of this message have been removed]
>
> 
>


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