[TRNSYS-users] QTSABS vs QSOLTR

Mon Dec 3 08:54:30 PST 2018

Karol,

This equation isn’t correct!

The absorbed solar radiation on the inside of opaque surfaces of a zone are

Qabsi_opq = QTSABS – QSEC = QSOLTR – QTSOUT – Qabsi_win_out

with

Qabsi_win_out … is solar radiation absorbed by windows (panes, frame and internal shading devices) when radiation is incident from inside.

In your example, QTSOUT is relative small compared to QSEC. This means that not much radiation is leaving the zone.  Then QTSABS is larger than QSOLTR because solar radiation is mainly absorbed when it is incident from outside.

I have the feeling that you didn’t get the definition of QSEC correctly:

the secondary heat flux of windows (panes, frame and internal shading devices) ( = QSEC, NType 56).
In this case the secondary heat flux is the part of solar radiation that is absorbed solar radiation (incident from outside and inside) by the windows
and going inside to the airnode as radiative and convective gain.

I encourage you to look at certain time step at the numbers for a zone (A10) with the select outputs of Balance 1 (starting from NTYPE 910).

Balance 1 provides an good overview where radiation goes.

Marion

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Von: Karol Bandurski <karol.bandurski at put.poznan.pl>
Gesendet: Donnerstag, 29. November 2018 17:41:23
An: hotline; 'TRNSYS users mailing list at OneBuilding.org'
Betreff: RE: [TRNSYS-users] QTSABS vs QSOLTR

Dear Marion,

So, if I understand, in my case (lack of internal shading), QSOLTR should be bigger than QTSABS because it includes also QTSOUT and radiation that is absorbed by windows but then transferred by convection to outside:

QSOLTR=QTSABS+QTSOUT+radiation absorbed by windows and then transferred by convection to outside.

If I am right:

1)      Way QSOLTR < QTSABS in my case?

2)      Solar gain is QTSABS because it represents solar radiation that is captured inside zone while QSOLTR include also QSTOUT and radiation absorbed by windows and then transferred by convection to outside.

I would be grateful for more clarification!

Kind regards,
Karol

From: hotline [mailto:hotline at Transsolar.com]
Sent: Thursday, November 29, 2018 2:30 PM
To: Karol Bandurski; 'TRNSYS users mailing list at OneBuilding.org'
Subject: AW: [TRNSYS-users] QTSABS vs QSOLTR

Dear Karol,

I have to confess that this is a little confusing.

For better understanding of the differences of QSOLTR and QTSABS it is important to understand the considered “parts”.

QSOLTR is the total shortwave solar radiation transmitted through all external windows including shading device into the airnode.

Then in the airnode this radiation is distributed to surfaces (taking into reflection). (For simplicity reasons we assume that there are no adjacent windows).

As a results QSOLTR is either

a) immediately transferred as convective heat gain to the internal air (= Qsolair, doesn’t exist in Trnsys 17) or is

b) absorbed by walls or

b) is absorbed by windows (panes, frame and internal shading devices) as radiation leaves (!) the airnode to the outside or

c) is transmitted to the outside (= QTSOUT, NType 73)

QTSABS (NType 75) consists of

  1.  solar radiation is absorbed by walls and
  2.  the secondary heat flux of windows (panes, frame and internal shading devices) ( = QSEC, NType 56).
In this case the secondary heat flux is the part of solar radiation that is absorbed by windows when solar radiation is entering and leaving the airnode
and going inside to the airnode.

Thus, QSOLTR and QTSABS consider different parts of the solar radiation.

I assume you are looking something like QSOLTR – QTSOUT.

I hope this explanation helps.

Kind regards,

Marion

Von: Karol Bandurski <karol.bandurski at put.poznan.pl>
Gesendet: Freitag, 23. November 2018 09:39
An: hotline <hotline at Transsolar.com>; 'TRNSYS users mailing list at OneBuilding.org' <trnsys-users at lists.onebuilding.org>
Betreff: RE: [TRNSYS-users] QTSABS vs QSOLTR

Dear Christoph,

Thank you for your response!

The problem is that, it seems to me, that I don’t have internal shading, so QSOLTR should equal QTSABS. Am I right?

How should I set window type and external devices to get QSOLTR=QTSABS?

Kind regards,
Karol

From: hotline [mailto:hotline at Transsolar.com]
Sent: Thursday, November 22, 2018 4:57 PM
To: TRNSYS users mailing list at OneBuilding.org
Subject: Re: [TRNSYS-users] QTSABS vs QSOLTR

Dear Karol,

QSOLTR is the total shortwave solar radiation transmitted through external windows and internal shading.

QTSABS also includes the secondary heat flux which includes the convection of internal shader.

Hope that clarifies your energy balance a bit.

Best,

Christoph

Von: TRNSYS-users <trnsys-users-bounces at lists.onebuilding.org<mailto:trnsys-users-bounces at lists.onebuilding.org>> Im Auftrag von Karol Bandurski via TRNSYS-users
Gesendet: Mittwoch, 21. November 2018 16:42
An: trnsys-users at lists.onebuilding.org<mailto:trnsys-users at lists.onebuilding.org>
Cc: Karol Bandurski <karol.bandurski at put.poznan.pl<mailto:karol.bandurski at put.poznan.pl>>
Betreff: [TRNSYS-users] QTSABS vs QSOLTR

Dear All,

I am going to find whole solar gain which come to zone throug windows.

There are two outputs that I consider: QTSABS and QSOLTR.

It seems to me that bigger should be QSOLTR, because it is shortwave radiation transmitted through window (but not kept 100% in air node).

The QTSABS is what exactly has been kept - has been absorbed by inside surfaces.

But it is appear that QTSABS > QSOLTR…

Could you write me what is right interpretation of those outputs?

Kind regards,
Karol

--------------------------------------------------------------------

Karol BANDURSKI M. Sc.

Faculty of Civil and Environemntal Engeneering

Division of Heating, Air Conditioning and Air Protection

Poznan University of Technology

https://www.researchgate.net/profile/Karol_Bandurski

www.put.poznan.pl/~karol.bandurski<http://www.put.poznan.pl/~karol.bandurski>

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