Details:ShortWave - Versionsgeschichte

Len: /* Short-wave Radiation Absorptivity */

2008-09-30T18:59:49Z

Short-wave Radiation Absorptivity

← Nächstältere Version		Version vom 30. September 2008, 20:59 Uhr
Zeile 122:		Zeile 122:
	<P>		<P>
	The absorptivity coefficients are entered in the		The absorptivity coefficients are entered in the
	[[2D:~~Dialog_Surface~~ \| dialog "Surface Transfer		[[1D:Dialog_SurfaceTransferCoefficients \| dialog "Surface Transfer
	Coefficients"]].		Coefficients"]].
	</P>		</P>

Len am 30. September 2008 um 18:59 Uhr

2008-09-30T18:59:07Z

← Nächstältere Version		Version vom 30. September 2008, 20:59 Uhr
Zeile 23:		Zeile 23:
	</P>		</P>

	~~<TABLE>~~		q = a<SUB>s</SUB> · I<BR>
	~~<TR><TD WIDTH="20"> </TD>~~		<BR>
	~~<TD COLSPAN="4">~~q = a<SUB~~><SMALL~~>s~~</SMALL>~~</SUB> · I<~~/TD~~>
	~~</TR>~~		q [W/m²]: heat flow due to solar radiation<BR>
	~~<TR><TD COLSPAN="5">~~ <~~/TD></TR~~>		<BR>
	~~<TR><TD> </TD>~~		a<SUB><SMALL>s</SMALL></SUB> [-]: 'short-wave' radiation absorptivity<BR>
	~~<TD>~~q~~</TD>~~		<BR>
	~~<TD>~~[W/m²]~~</TD>~~		Iv[W/m²]: solar radiation vertical to component surface<BR>
	~~<TD>~~:~~</TD>~~
	~~<TD>~~heat flow due to solar radiation<~~/TD~~>
	~~</TR>~~
	~~<TR><TD>~~ <~~/TD~~>
	~~<TD>~~a<SUB><SMALL>s~~</SUB>~~</SMALL></~~TD>~~
	~~<TD~~>[-]~~</TD>~~
	~~<TD>~~:~~</TD>~~
	~~<TD>~~'short-wave' radiation absorptivity<~~/TD>~~
	~~</TR~~>
	~~<TR><TD>~~ <~~/TD~~>
	~~<TD>I</TD>~~
	~~<TD>~~[W/m²]~~</TD>~~
	~~<TD>~~:~~</TD>~~
	~~<TD>~~solar radiation vertical to component surface<~~/TD~~>
	~~</TABLE>~~

	<P>		<P>
Zeile 136:		Zeile 122:
	<P>		<P>
	The absorptivity coefficients are entered in the		The absorptivity coefficients are entered in the
	[[1D:Dialog_Surface \| dialog "Surface Transfer		[[2D:Dialog_Surface \| dialog "Surface Transfer
	Coefficients"]].		Coefficients"]].
	</P>		</P>

Len am 13. August 2008 um 11:17 Uhr

2008-08-13T11:17:45Z

← Nächstältere Version		Version vom 13. August 2008, 13:17 Uhr
Zeile 35:		Zeile 35:
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>a<SUB><SMALL>s</SUB></SMALL></TD>		<TD>a<SUB><SMALL>s</SUB></SMALL></TD>
	<TD>[-]</TD>		<TD>[-]</TD>
	<TD>:</TD>		<TD>:</TD>
	<TD>'short-wave' radiation absorptivity</TD>		<TD>'short-wave' radiation absorptivity</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>I</TD>		<TD>I</TD>
	<TD>[W/m²]</TD>		<TD>[W/m²]</TD>
	<TD>:</TD>		<TD>:</TD>
	<TD>solar radiation vertical to component surface</TD>		<TD>solar radiation vertical to component surface</TD>
	</TABLE>		</TABLE>

	<P>		<P>
	WUFI calculates the radiation load vertical to the surface from the data in the		WUFI calculates the radiation load vertical to the surface from the data in the
	~~<A HREF="DialogClimate.htm">~~climate file~~</A>~~, multiplies it - if positive - by the		[[1D:Dialog_Climate \| climate file]], multiplies it - if positive - by the
	s.r.a. and applies the result as a heat source at the surface of the component. (If		s.r.a. and applies the result as a heat source at the surface of the component. (If
	the radiation load computed from the climate data is negative, it is multiplied by the		the radiation load computed from the climate data is negative, it is multiplied by the
	~~<A HREF="LongWaveRadiationEmissivity.htm">~~long-wave radiation emissivity~~</A>~~.) [##update##]		[[Details:LongWave \| long-wave radiation emissivity]].) [##update##]
	</P>		</P>

Zeile 60:		Zeile 60:
	<TABLE>		<TABLE>
	<TR><TD WIDTH="10"> </TD>		<TR><TD WIDTH="10"> </TD>
	<TD>plaster, white (aged)<BR> </TD>		<TD>plaster, white (aged)<BR> </TD>
	<TD WIDTH="20"> </TD>		<TD WIDTH="20"> </TD>
	<TD VALIGN="TOP">0.4</TD>		<TD VALIGN="TOP">0.4</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>roof tile, red</TD>		<TD>roof tile, red</TD>
	<TD> </TD>		<TD> </TD>
	<TD VALIGN="TOP">0.6</TD>		<TD VALIGN="TOP">0.6</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>klinker brick, dark red</TD>		<TD>klinker brick, dark red</TD>
	<TD> </TD>		<TD> </TD>
	<TD VALIGN="TOP">0.7</TD>		<TD VALIGN="TOP">0.7</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>roof tile, brown<BR> </TD>		<TD>roof tile, brown<BR> </TD>
	<TD> </TD>		<TD> </TD>
	<TD VALIGN="TOP">0.8</TD>		<TD VALIGN="TOP">0.8</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>bituminous roof covering<BR> </TD>		<TD>bituminous roof covering<BR> </TD>
	<TD> </TD>		<TD> </TD>
	<TD VALIGN="TOP">0.9</TD>		<TD VALIGN="TOP">0.9</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>wood (spruce):</TD>		<TD>wood (spruce):</TD>
	<TD> </TD>		<TD> </TD>
	<TD> </TD>		<TD> </TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>untreated</TD>		<TD>untreated</TD>
	<TD> </TD>		<TD> </TD>
	<TD VALIGN="TOP">0.4</TD>		<TD VALIGN="TOP">0.4</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>weathered (silver-gray)</TD>		<TD>weathered (silver-gray)</TD>
	<TD> </TD>		<TD> </TD>
	<TD VALIGN="TOP">0.7</TD>		<TD VALIGN="TOP">0.7</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>painted brown<BR> </TD>		<TD>painted brown<BR> </TD>
	<TD> </TD>		<TD> </TD>
	<TD VALIGN="TOP">0.8</TD>		<TD VALIGN="TOP">0.8</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>Schilf sandstone:</TD>		<TD>Schilf sandstone:</TD>
	<TD> </TD>		<TD> </TD>
	<TD> </TD>		<TD> </TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>dry</TD>		<TD>dry</TD>
	<TD> </TD>		<TD> </TD>
	<TD VALIGN="TOP">0.7</TD>		<TD VALIGN="TOP">0.7</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>wet<BR> </TD>		<TD>wet<BR> </TD>
	<TD> </TD>		<TD> </TD>
	<TD VALIGN="TOP">0.85</TD>		<TD VALIGN="TOP">0.85</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>red Main sandstone<BR> </TD>		<TD>red Main sandstone<BR> </TD>
	<TD> </TD>		<TD> </TD>
	<TD VALIGN="TOP">0.75</TD>		<TD VALIGN="TOP">0.75</TD>
	</TR>		</TR>
	<TR><TD> </TD>		<TR><TD> </TD>
	<TD>sandstone with patina</TD>		<TD>sandstone with patina</TD>
	<TD> </TD>		<TD> </TD>
	<TD VALIGN="TOP">0.9</TD>		<TD VALIGN="TOP">0.9</TD>
	</TABLE>		</TABLE>

Len: Die Seite wurde neu angelegt: = Short-wave Radiation Absorptivity =
The heat transfer coefficients already contain a component which describes the long-wave radiation...

2008-08-13T11:13:03Z

Die Seite wurde neu angelegt: = Short-wave Radiation Absorptivity = The heat transfer coefficients already contain a component which describes the long-wave radiation...

Neue Seite

= Short-wave Radiation Absorptivity =


The [[Details:HeatTransfer | heat transfer coefficients]] already contain
a component which describes the long-wave radiation exchange with other surrounding
surfaces. The temperature of these surfaces is assumed to be approximately equal to
the air temperature.


The solar radiation, however, which shows a pronounced diurnal variation, can by no
means be related to the air temperature. Since its effect on the surface temperatures
cannot be neglected, it must be treated separately.


Whereas the radiation exchange between the building component and the surroundings
(T ≈ 300 K) essentially takes place in the infrared, the spectrum of the solar
radiation (T ≈ 6000 K) also contains a considerable amount of short-wave radiation.
For this reason, the solar radiation is also simply called 'short-wave radiation'.


The short-wave radiation absorptivity indicates the fraction of the total (i.e.,
long- and short-wave) solar radiation incident on the component surface which is absorbed:


<TABLE>
<TR><TD WIDTH="20"> </TD>
<TD COLSPAN="4">q = as · I</TD>
</TR>
<TR><TD COLSPAN="5"> </TD></TR>
<TR><TD> </TD>
<TD>q</TD>
<TD>[W/m²]</TD>
<TD>:</TD>
<TD>heat flow due to solar radiation</TD>
</TR>
<TR><TD> </TD>
<TD>as</TD>
<TD>[-]</TD>
<TD>:</TD>
<TD>'short-wave' radiation absorptivity</TD>
</TR>
<TR><TD> </TD>
<TD>I</TD>
<TD>[W/m²]</TD>
<TD>:</TD>
<TD>solar radiation vertical to component surface</TD>
</TABLE>


WUFI calculates the radiation load vertical to the surface from the data in the
<A HREF="DialogClimate.htm">climate file</A>, multiplies it - if positive - by the
s.r.a. and applies the result as a heat source at the surface of the component. (If
the radiation load computed from the climate data is negative, it is multiplied by the
<A HREF="LongWaveRadiationEmissivity.htm">long-wave radiation emissivity</A>.) [##update##]



Examples:

<TABLE>
<TR><TD WIDTH="10"> </TD>
<TD>plaster, white (aged)  </TD>
<TD WIDTH="20"> </TD>
<TD VALIGN="TOP">0.4</TD>
</TR>
<TR><TD> </TD>
<TD>roof tile, red</TD>
<TD> </TD>
<TD VALIGN="TOP">0.6</TD>
</TR>
<TR><TD> </TD>
<TD>klinker brick, dark red</TD>
<TD> </TD>
<TD VALIGN="TOP">0.7</TD>
</TR>
<TR><TD> </TD>
<TD>roof tile, brown  </TD>
<TD> </TD>
<TD VALIGN="TOP">0.8</TD>
</TR>
<TR><TD> </TD>
<TD>bituminous roof covering  </TD>
<TD> </TD>
<TD VALIGN="TOP">0.9</TD>
</TR>
<TR><TD> </TD>
<TD>wood (spruce):</TD>
<TD> </TD>
<TD> </TD>
</TR>
<TR><TD> </TD>
<TD>untreated</TD>
<TD> </TD>
<TD VALIGN="TOP">0.4</TD>
</TR>
<TR><TD> </TD>
<TD>weathered (silver-gray)</TD>
<TD> </TD>
<TD VALIGN="TOP">0.7</TD>
</TR>
<TR><TD> </TD>
<TD>painted brown  </TD>
<TD> </TD>
<TD VALIGN="TOP">0.8</TD>
</TR>
<TR><TD> </TD>
<TD>Schilf sandstone:</TD>
<TD> </TD>
<TD> </TD>
</TR>
<TR><TD> </TD>
<TD>dry</TD>
<TD> </TD>
<TD VALIGN="TOP">0.7</TD>
</TR>
<TR><TD> </TD>
<TD>wet  </TD>
<TD> </TD>
<TD VALIGN="TOP">0.85</TD>
</TR>
<TR><TD> </TD>
<TD>red Main sandstone  </TD>
<TD> </TD>
<TD VALIGN="TOP">0.75</TD>
</TR>
<TR><TD> </TD>
<TD>sandstone with patina</TD>
<TD> </TD>
<TD VALIGN="TOP">0.9</TD>
</TABLE>


WUFI offers a list of predefined surfaces with their respective short-wave absorptivities
for selection, a user-defined value may be entered as well.


The absorptivity coefficients are entered in the
[[1D:Dialog_Surface | dialog "Surface Transfer
Coefficients"]].

Details:ShortWave - Versionsgeschichte

Len: /* Short-wave Radiation Absorptivity */

Len am 30. September 2008 um 18:59 Uhr

Len am 13. August 2008 um 11:17 Uhr

Len: Die Seite wurde neu angelegt: = Short-wave Radiation Absorptivity = The heat transfer coefficients already contain a component which describes the long-wave radiation...

Len: Die Seite wurde neu angelegt: = Short-wave Radiation Absorptivity =
The heat transfer coefficients already contain a component which describes the long-wave radiation...