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

[Jon Hand]

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