[esp-r] Re: furniture in esp-r

[Jon Hand]

One of the exemplar models (a variant of the two cellular offices with passageway) includes
explicit furniture - a desk at a window and a filing cabinet.  Both the desk and the filing
cabinet are represented as back-to-back surfaces.  The constructions have been adapted
to be half the thickness of the actual furniture.  To give a visual clue the filing cabinet
has also been represented as a shading block of the appropriate size.

The usual rule of thumb is to derive the total surface area of the object and
give half to each surface.  Some people aggregate a number of similar objects
into one pair of surfaces.  Position is optional - if it helps to put the object correctly
in the room do so, otherwise if position is not critical then rough locations are
fine.

The pairs of surfaces interact as normal with the other surfaces in the room so
you can do viewfactor calcs if you want and include them in heat transfer coefficient
regimes and they can be insolated if a shading analysis is done.

For an object that rests on the floor you could extrude it into the room as a separate
zone. It is also possible to have a zone within a zone (as long as the bounding zone
shares the surfaces of the inner zones).

Experience in several commercial office building projects indicates that the internal
clutter in offices can be substantial and if a design team is interested in the response
of a building (e.g. heating startup) then some provision for internal thermal clutter
(desks, cabinets, partitions) does seem to improve the fit.  

Many simulation environments do not allow/support internal thermal clutter, some 
allow it in an abstract form (mass without location).  More importantly, very few
practitioners seem to be aware of such facilities and make use of them.

Regards, Jon Hand
________________________________________
From: esp-r-bounces at lists.strath.ac.uk [esp-r-bounces at lists.strath.ac.uk] On Behalf Of Achim Geissler [achim.geissler at intergga.ch]
Sent: 23 May 2011 20:13
To: leen peeters
Cc: esp-r at lists.strath.ac.uk
Subject: [esp-r] Re: furniture in esp-r

Hi Leen

of course, you could model the furniture as small zones in a large one (with the floor of the furniture connecting to the floor of the large zone) ... this would lead to quite a complex "main zone", though.

Yes, hanging surfaces can be set up with the normal attributes as any other surface, so the adaptive convection should not be a problem.

Best
Achim



On May 23, 2011, at 8:43 PM, leen peeters wrote:

Hi Achim,

we planned to do some experiments to see how things should be taken into account, what the influence is on all modes of heat transfer for a range of potential settings.
It seemed usefull to first check how popular building simulation codes handle the issue.
So, I will take the explanation below and I assume it can be coupled to the adaptive convection algorithm.

What I mean by loading and unloading is that the volume, representing the furniture, has to take part in convection and radiation (and potentially some conduction) in order to exchange heat and thus influence its thermal state.

Leen

On Mon, May 23, 2011 at 8:36 PM, Achim Geissler <achim.geissler at intergga.ch<mailto:achim.geissler at intergga.ch>> wrote:
Dear Leen

possibly you want to use "hanging surfaces". I am not sure what you mean by "charging and discharging" other than thermal capacity, but such hanging surfaces have all the same properties as normal zone bounding surfaces.

"Furniture against the wall" is a difficult one. As a first thought, you can "cut the appropriate surface into the wall" and then give this surface a different construction which has an additional layer and thermal resistance on the interior. I assume you would like to have reduced surface temperatures in the region of the furniture?

However, often problems arise when thermal bridging (internal walls meet external walls, floors meet external walls and such) and furniture "collide". For this, you would need an (at least) 2d calculation, I would say. ESP-r has such a module, however, I do not know if it is still "active".

For what its worth.

Best
Achim


On May 23, 2011, at 8:23 PM, leen peeters wrote:

> Dear all,
>
> what is the best way of modelling the effect of furniture in ESP-r? I mean not only the thermal capacity, but the charging and discharging of it and the potential effect of furniture that is located against a wall.
>
> Thanks already,
>
> Leen
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