[TRNSYS-users] Type 56, components of heat gains

[Diego A. Arias]

Hi Timo,

Sorry for taking so long to answer your question. I needed help from our 
building experts.  Marion Hiller from Transsolar helped me figure out 
how to verify these values.

The best way to know how the building is calculating  the transmission 
of solar radiation is to back calculate the transmissivity, absorptivity 
and reflectivity of the window.

With an equation you can calculate the energy that is hitting the window:
Q_total = I_total_on_facade * Area_window,
where I_total_on_facade is the total radiation on the orientation 
corresponding to the window.

If you ask the additional outputs from the building QSOLTR (ntype 12) 
and QTSPAS (ntype 74), then you can calculate the values of
transmissivity = QSOLTR / Q_total
absorptivity = (QTSPAS - QSOLTR)/Q_total
reflectivity  = ( Q_total - QTSPAS)/Q_total

Then, you can finally compare these values with the data in the window 
library corresponding to the specific glassing that you used.

I am attaching a modified version of the SunSpace example.  It contains 
the results of the above calculations.  Let's pick a time so we can 
compare:  at hour 36, the calculated values are:
transmissivity = 0.34
absorptivity = 0.36
reflectivity = 0.29 
Incident_angle = 24°

If you go to TrnBuild, then to the window manager, and finally to the 
WinID library, you will see that the properties of the glazing used are:
transmissivity_beam (Tsol)@30° = 0.413 ; transmissivity_hemispherical = 
0.354
absorptivity_beam at 30° = Abs1 + Abs2 = 0.123+0.201 = 0.321; 
absorptivity_hemispherical = 0.132 + 0.191 = 0.323
(There are two values of absorptivity, one for each of the surfaces of 
the glazing).
reflectivity_beam(Rfsol)@30° = 0.262;  reflectivity_hemispherical = 0.314

The overall results that you get with the above equations are weighted 
averages for the beam and solar radiation.

In addition, you can also ask for ntype903, which is a balance of solar 
radiation on a window.
I hope this helps.  Please do not hesitate to contact me again if you 
have additional questions.
Best regards,

Diego

Timo Sengewald wrote:

>Diego,
>
>thanks for your answer. I already tried QSOLTR but it seems the amount
>delivered is too low and I tried QTSPAS (NType 74) which delivers more
>plausible values (compared with the incidence radiation on the outside
>wall).
>
>The documentation says about QSOLTR:
>
>NTYPE 12: QSOLTR total shortwave solar radiation transmitted through
>external windows of
>zone (but not kept 100 % in zone) [kJ/hr]
>
>Isn't the shortwave radiation the visible part of the solar radiation? That
>would explain the pretty low energy rate. 
>
>Best regards,
>Timo
>
>________________________________________________
>Timo Sengewald
>
>BLS Energieplan GmbH
>Elsenstraße 106
>D-12435 Berlin
>Tel.: +49 30 53 32 81-0
>Fax: +49 30 53 32 81-40
>
>
>www.bls-energieplan.de
>
>
>
>
>
>-----Ursprüngliche Nachricht-----
>Von: trnsys-users-bounces at engr.wisc.edu
>[mailto:trnsys-users-bounces at engr.wisc.edu] Im Auftrag von Diego A. Arias
>Gesendet: Freitag, 17. März 2006 23:51
>An: Timo Sengewald
>Cc: trnsys-users at engr.wisc.edu; ausgang at bls-energieplan.de
>Betreff: Re: [TRNSYS-users] Type 56, components of heat gains
>
>
>Dear Timo,
>
>Ntype12 (QSOLTR) gives you the total shortwave solar radiation 
>transmitted through external windows for a given zone.
>Best regards,
>
>Diego
>
>
>Timo Sengewald wrote:
>
>  
>
>>Hello!
>> 
>>Currently I try to estimate the single components the total thermal
>>gain of a room is composed of (observing a single day). Could somebody 
>>tell me which NTYPES of type 56 deliver the solar radiation 
>>transmitted through the windows?
>> 
>>
>>Thanks for your help!
>>
>> 
>>Best regards,
>> 
>>Timo
>>
>>
>>________________________________________________
>>Timo Sengewald
>>
>>BLS Energieplan GmbH
>>Elsenstraße 106
>>D-12435 Berlin
>>Tel.: +49 30 53 32 81-0
>>Fax: +49 30 53 32 81-40
>>
>>
>>www.bls-energieplan.de
>> 
>>
>>-----------------------------------------------------------------------
>>-
>>
>>_______________________________________________
>>TRNSYS-users mailing list
>>TRNSYS-users at engr.wisc.edu 
>>https://www.cae.wisc.edu/mailman/listinfo/trnsys-users
>> 
>>
>>    
>>
>
>
>  
>


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