[esp-r] Re: TMC and thermophysical property replacement

[Achim Geissler]

Hi Marc,
some careful replies:
1) possibly, if the actual construction is not transparent, using the physical property substitution by itself may be easier (I seem to remember there is one(?)).
2) Generally, abs + tran + ref must be 1.0 (for every angle). This is the only "restriction" as far as I am aware. However, setting trans to zero may cause problems (we never went below 0.001 because of problems).
3) No, this is changed by the thermal construction entry
4) As far as I am aware, there is no easily understood example. However, the general procedure is quite straightforward. You need to know the index of the alternative construction to be used and enter this in the .tmc file as described. But, if you change / edit your construction database, the index will change and it won't work anymore. Moreover, the exchanged construction must have the same number of layers.
Regards,
Achim


> -----Original Message-----
> From: esp-r-bounces at lists.strath.ac.uk [mailto:esp-r-
> bounces at lists.strath.ac.uk] On Behalf Of esp-r at h-rd.org
> Sent: Thursday, September 14, 2006 4:06 PM
> To: esp-r at lists.strath.ac.uk
> Cc: esp-r at h-rd.org
> Subject: [esp-r] TMC and thermophysical property replacement
> 
> Dear esp-r list members,
> 
> currently I am experimenting with optical control in TMC files.
> Basically I have several questions:
> 
> 1) My objective is to control the absorbed solar radiation of a
> construction.
> The construction is not transparent, but it seems to me that using ESP-r,
> I can
> models this construction as transparent.  Is this a reasonable approach?
> 
> 2) Is ther specific documentation available on making the optical property
> set
> for a construction?  for example for my construction I have set the
> visible
> transmittance to 0,  and also the direct solar transmittance = 0.  It
> seems that
> then the absortion of the different layers is not free to choose anymore?
> 
> 3) Do the optical properties change the value of the emissivity?
> 
> 4)  In the manual (Data Model Summary, ESP-r Version 9 Series, page 25) it
> is
> stated:
>    "In addition, it is possible to replace the thermophysical properties
> of
>    the TMC. For each control period, an index points to an alternative set
>    of thermophysical properties from a construction in the multi-
> constructional
>    database. It is important that the number of elements in the
> replacement
>    construction is the same as for the original construction. The
> replacement
>    values are read in and stored in this file. If the index is zero, the
>    thermophysical properties are unchanged."
> Is there an example available?
> 
> 
> yours sincerely,
> 
> Marc Hoffmann
> esp-r at h-rd.org
> 
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