[esp-r] Re: Regarding thermal and optical properties of construction materials

[Satya]

Can I run the simulation by assigning IR emissivity and solar absorptivity
to materials located deep inside a construction? Like brick?


On Wed, May 8, 2013 at 4:59 PM, Jon Hand <jon at esru.strath.ac.uk> wrote:

>
> The issue of paint mentioned below.  There are several examples of
> applying paint or a coating
> to materials. - there are several types of concrete which are identical
> except for
> the surface properties  - white painted and stone colour.  Or Steel and
> Beige painted steel and White painted steel.
>
> This approach is based on the assumption that the thin layer only makes a
> tiny impact on the conductivity
> density and specific heat of the material.
>
> I would advise against treating a paint layer as transparent.  Seems
> overly complex and
> getting the optical data would be a challenge.
>
> Surface solar absorption and emissivity is sometimes based on approximate
> information in
> the literature of building simulation.  It is possible to measure, few
> people do this.
>
> Regards, Jon Hand
> ________________________________________
> From: esp-r-bounces at lists.strath.ac.uk [esp-r-bounces at lists.strath.ac.uk]
> On Behalf Of Satya [ringo.satyarr at gmail.com]
> Sent: 08 May 2013 09:18
> To: ESP-r Users' Club
> Subject: [esp-r] Regarding thermal and optical properties of construction
>       materials
>
>  Hi
>
> 1. Thermal properties:
>
>  I have a list of building materials used for the building I am trying to
> model. Unfortunately, none of these materials are listed in the ESP-r
> library. Where can I find the relevant properties of those materials which
> ESP-r needs to run a simulation? Here is the list of the materials.
>
> _________________________________________
>
> 1 : 1.67 : 2.84 reinforced concrete (C:S:A)
>
> 1:4 cement mortar plaster
>
> 1:4 cement sand plaster
>
> vitrified tiles
>
> typical values for fiberglass reinforced plastic
>
> typical values for ply
>
> typical values for brickbat
>
> _________________________________________
>
>
>
> 2. Optical properties
>
>  The library doesn't include layers of paint. I intend to create a new
> material by assigning the following properties:
>
> conductivity: infinite // is this allowed
>
> density: 0 // is this allowed
>
> specific heat: same as that of underlying plaster
>
>
>
> But how do I estimate IR emissivity and solar absorptivity? The internal
> paint is a white and external is grey. Is there an easy way to measure it
> or are there typical values for paints depending on the colour? Where do I
> find this data?
>
>  It also occurred to me that the paint layer, being very thin, could be
> modelled as a transparent construction because my guess is that it does let
> light pass through because of how thin it is. However, for this I will need
> to find 8 optical properties of paint (3 types of transmittances, 4 types
> of reflectences and colour rendering).
>
> I understand that this is more accurate but if anybody tells me that an
> opaque material type paint won't lead to major inaccuracies, I will gladly
> work with an opaque paint.
>
>  Where do I find the detailed optical data of 'white emulsion paint' and
> 'grey emulsion paint’?
>
>  Thanks,
>
> Satya
>
>
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