Thermal optical properties - Revision history

https://www.designingbuildings.co.uk/w/index.php?action=history&feed=atom&title=Thermal_optical_properties Thermal optical properties - Revision history 2026-05-10T12:25:46Z Revision history for this page on the wiki MediaWiki 1.17.4 https://www.designingbuildings.co.uk/w/index.php?title=Thermal_optical_properties&diff=219443&oldid=prev Editor at 18:28, 1 December 2021 2021-12-01T18:28:10Z

<p></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr valign='top'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 18:28, 1 December 2021</td> </tr><tr><td colspan="2" class="diff-lineno">Line 35:</td> <td colspan="2" class="diff-lineno">Line 35:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>According to Kirchoff's law the emissivity of a surface is equal to its radiant absorptivity at a given temperature and wavelength.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>According to Kirchoff's law the emissivity of a surface is equal to its radiant absorptivity at a given temperature and wavelength.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>= Related articles on Designing Buildings <del class="diffchange diffchange-inline">Wiki </del>=</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>= Related articles on Designing Buildings =</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Albedo.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Albedo.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Computational fluid dynamics (CFD).</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Computational fluid dynamics (CFD).</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Electromagnetic energy.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Electromagnetic energy.</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">* Electromagnetic spectrum.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Emissivity.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Emissivity.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* g-value.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* g-value.</div></td></tr> </table>

Editor https://www.designingbuildings.co.uk/w/index.php?title=Thermal_optical_properties&diff=199704&oldid=prev Designing Buildings at 06:28, 31 March 2021 2021-03-31T06:28:54Z

<p></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr valign='top'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 06:28, 31 March 2021</td> </tr><tr><td colspan="2" class="diff-lineno">Line 58:</td> <td colspan="2" class="diff-lineno">Line 58:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* U value.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* U value.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Visible light.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Visible light.</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">* X-rays.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:Standards_/_measurements]] [[Category:Sustainability]]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:Standards_/_measurements]] [[Category:Sustainability]]</div></td></tr> </table>

Designing Buildings https://www.designingbuildings.co.uk/w/index.php?title=Thermal_optical_properties&diff=199300&oldid=prev Designing Buildings at 07:50, 26 March 2021 2021-03-26T07:50:39Z

<p></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr valign='top'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 07:50, 26 March 2021</td> </tr><tr><td colspan="2" class="diff-lineno">Line 46:</td> <td colspan="2" class="diff-lineno">Line 46:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Light reflectance value.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Light reflectance value.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Low-e glass.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Low-e glass.</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">* Microwave.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Overheating.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Overheating.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Preventing overheating.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Preventing overheating.</div></td></tr> </table>

Designing Buildings https://www.designingbuildings.co.uk/w/index.php?title=Thermal_optical_properties&diff=199284&oldid=prev Designing Buildings at 07:32, 26 March 2021 2021-03-26T07:32:54Z

<p></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr valign='top'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 07:32, 26 March 2021</td> </tr><tr><td colspan="2" class="diff-lineno">Line 42:</td> <td colspan="2" class="diff-lineno">Line 42:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Emissivity.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Emissivity.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* g-value.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* g-value.</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">* Gamma rays.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Heat transfer.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Heat transfer.</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">* Hygrothermal.</del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Light reflectance value.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Light reflectance value.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Low-e glass.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Low-e glass.</div></td></tr> </table>

Designing Buildings https://www.designingbuildings.co.uk/w/index.php?title=Thermal_optical_properties&diff=199162&oldid=prev Designing Buildings at 08:52, 25 March 2021 2021-03-25T08:52:23Z

<p></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr valign='top'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 08:52, 25 March 2021</td> </tr><tr><td colspan="2" class="diff-lineno">Line 39:</td> <td colspan="2" class="diff-lineno">Line 39:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Albedo.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Albedo.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Computational fluid dynamics (CFD).</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Computational fluid dynamics (CFD).</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">* Electromagnetic energy.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Emissivity.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Emissivity.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* g-value.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* g-value.</div></td></tr> </table>

Designing Buildings https://www.designingbuildings.co.uk/w/index.php?title=Thermal_optical_properties&diff=180289&oldid=prev Designing Buildings at 08:33, 1 November 2020 2020-11-01T08:33:26Z

<p></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr valign='top'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 08:33, 1 November 2020</td> </tr><tr><td colspan="2" class="diff-lineno">Line 57:</td> <td colspan="2" class="diff-lineno">Line 57:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Visible light.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Visible light.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>[[Category:<del class="diffchange diffchange-inline">Standards_/_measurements</del>]] [[Category:<del class="diffchange diffchange-inline">DCN_Standard</del>]] [[Category:Sustainability]]</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>[[Category:<ins class="diffchange diffchange-inline">DCN_Definition</ins>]] [[Category:<ins class="diffchange diffchange-inline">DCN_Guidance]] [[Category:Standards_/_measurements</ins>]] [[Category:Sustainability]]</div></td></tr> </table>

Designing Buildings https://www.designingbuildings.co.uk/w/index.php?title=Thermal_optical_properties&diff=157231&oldid=prev Designing Buildings at 14:36, 26 March 2020 2020-03-26T14:36:58Z

<p></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr valign='top'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 14:36, 26 March 2020</td> </tr><tr><td colspan="2" class="diff-lineno">Line 35:</td> <td colspan="2" class="diff-lineno">Line 35:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>According to Kirchoff's law the emissivity of a surface is equal to its radiant absorptivity at a given temperature and wavelength.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>According to Kirchoff's law the emissivity of a surface is equal to its radiant absorptivity at a given temperature and wavelength.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">= Find out more =</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>= Related articles on Designing Buildings Wiki =</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">==</del>= Related articles on Designing Buildings Wiki <del class="diffchange diffchange-inline">==</del>=</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Albedo.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Albedo.</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 59:</td> <td colspan="2" class="diff-lineno">Line 57:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Visible light.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Visible light.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>[[Category:Standards_/_measurements]] [[Category:Sustainability]]</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>[[Category:Standards_/_measurements<ins class="diffchange diffchange-inline">]] [[Category:DCN_Standard</ins>]] [[Category:Sustainability]]</div></td></tr> </table>

Designing Buildings https://www.designingbuildings.co.uk/w/index.php?title=Thermal_optical_properties&diff=111417&oldid=prev Editor at 10:45, 16 July 2018 2018-07-16T10:45:18Z

<p></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr valign='top'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 10:45, 16 July 2018</td> </tr><tr><td colspan="2" class="diff-lineno">Line 15:</td> <td colspan="2" class="diff-lineno">Line 15:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>As the directional nature of radiation incident upon a material changes, so the relative proportion which is absorbed, transmitted or reflected may vary significantly. This means that in order to properly quantify the optical properties of a material it is necessary to measure its transmittance, reflectance and absorptance as a function of angle of incidence.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>As the directional nature of radiation incident upon a material changes, so the relative proportion which is absorbed, transmitted or reflected may vary significantly. This means that in order to properly quantify the optical properties of a material it is necessary to measure its transmittance, reflectance and absorptance as a function of angle of incidence.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Thermal radiation includes all those wavelengths of the electromagnetic spectrum which will heat a body when absorbed by it, ranging from about <del class="diffchange diffchange-inline">100nm </del>to 100,<del class="diffchange diffchange-inline">000nm</del>. In general, the higher the temperature of a body, the lower the average wavelength of the radiation it emits. The range of terrestrial temperatures experienced within the built environment is comparatively small, and relative to the temperature of the sun this range is 'cold' and hence radiating at a longer wavelength. This anomaly allows us to categorise thermal radiation as short-wave solar radiation and terrestrial or long wave infra-red radiation.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Thermal radiation includes all those wavelengths of the electromagnetic spectrum which will heat a body when absorbed by it, ranging from about <ins class="diffchange diffchange-inline">100 nm </ins>to 100,<ins class="diffchange diffchange-inline">000 nm</ins>. In general, the higher the temperature of a body, the lower the average wavelength of the radiation it emits. The range of terrestrial temperatures experienced within the built environment is comparatively small, and relative to the temperature of the sun this range is 'cold' and hence radiating at a longer wavelength. This anomaly allows us to categorise thermal radiation as short-wave solar radiation and terrestrial or long wave infra-red radiation.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The figure below shows the spectral distribution of this categorisation..</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The figure below shows the spectral distribution of this categorisation..</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 23:</td> <td colspan="2" class="diff-lineno">Line 23:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>= Solar optical properties =</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>= Solar optical properties =</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Solar radiation may be considered to include the ultra violet, visible and near or short wave infra-red wavebands. Around 97% of the solar radiation incident upon the earth's surface is within the range 300 to 2,<del class="diffchange diffchange-inline">300nm</del>. Its spectral profile is roughly analogous to that of a black body at <del class="diffchange diffchange-inline">5762°K</del>, and as terrestrial temperatures are unlikely to reach anything like this temperature, solar radiation reaching the earth may be treated as a pure thermal gain.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Solar radiation may be considered to include the ultra violet, visible and near or short wave infra-red wavebands. Around 97% of the solar radiation incident upon the earth's surface is within the range 300 to 2,<ins class="diffchange diffchange-inline">300 nm</ins>. Its spectral profile is roughly analogous to that of a black body at <ins class="diffchange diffchange-inline">5,762°K</ins>, and as terrestrial temperatures are unlikely to reach anything like this temperature, solar radiation reaching the earth may be treated as a pure thermal gain.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The continually changing position of the earth relative to the sun, and the diffusing nature of the atmosphere gives solar radiation incident upon the earth's surface a complex directional composition. For simplicity however, this is usually considered to consist of entirely diffuse, and entirely direct beam components. If the direct beam solar optical properties of a material are known for all angles of incidence, then its diffuse properties may be calculated by integration.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The continually changing position of the earth relative to the sun, and the diffusing nature of the atmosphere gives solar radiation incident upon the earth's surface a complex directional composition. For simplicity however, this is usually considered to consist of entirely diffuse, and entirely direct beam components. If the direct beam solar optical properties of a material are known for all angles of incidence, then its diffuse properties may be calculated by integration.</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 53:</td> <td colspan="2" class="diff-lineno">Line 53:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Solar heat gain coefficient.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Solar heat gain coefficient.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Solar transmittance (gtot).</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Solar transmittance (gtot).</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">* The effects of electromagnetic fields in the workplace.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Thermal bridge.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Thermal bridge.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Thermography for traditional buildings.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Thermography for traditional buildings.</div></td></tr> </table>

Editor https://www.designingbuildings.co.uk/w/index.php?title=Thermal_optical_properties&diff=98001&oldid=prev Editor at 12:58, 8 February 2018 2018-02-08T12:58:50Z

<p></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr valign='top'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 12:58, 8 February 2018</td> </tr><tr><td colspan="2" class="diff-lineno">Line 29:</td> <td colspan="2" class="diff-lineno">Line 29:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>= Long wave infra-red optical properties =</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>= Long wave infra-red optical properties =</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Most 'terrestrial' radiation occurs within the far or long wave infra-red wavebands. The wavelength of terrestrial radiation varies with temperature, however at room temperature approximately 97% of the radiation emanating from a perfect emitter will be within the range 3,<del class="diffchange diffchange-inline">000nm </del>to 50,<del class="diffchange diffchange-inline">000nm</del>.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Most 'terrestrial' radiation occurs within the far or long wave infra-red wavebands. The wavelength of terrestrial radiation varies with temperature, however at room temperature approximately 97% of the radiation emanating from a perfect emitter will be within the range 3,<ins class="diffchange diffchange-inline">000 nm </ins>to 50,<ins class="diffchange diffchange-inline">000 nm</ins>.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Terrestrial surfaces emit long wave infra-red radiation in all directions within a hemisphere about their azimuth. This hemisphere can include a wide variety of thermal bodies, ranging from the clear night sky to relatively 'hot' solid bodies all of which will be emitting different intensities and wavelengths of thermal radiation themselves. In order to simplify this complex situation terrestrial radiation is generally treated as an average heat transfer based on hemispherical emissivities and average hemispherical surface temperatures.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Terrestrial surfaces emit long wave infra-red radiation in all directions within a hemisphere about their azimuth. This hemisphere can include a wide variety of thermal bodies, ranging from the clear night sky to relatively 'hot' solid bodies all of which will be emitting different intensities and wavelengths of thermal radiation themselves. In order to simplify this complex situation terrestrial radiation is generally treated as an average heat transfer based on hemispherical emissivities and average hemispherical surface temperatures.</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 52:</td> <td colspan="2" class="diff-lineno">Line 52:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Solar gain.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Solar gain.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Solar heat gain coefficient.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Solar heat gain coefficient.</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">* Solar transmittance (gtot).</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Thermal bridge.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Thermal bridge.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Thermography for traditional buildings.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Thermography for traditional buildings.</div></td></tr> </table>

Editor https://www.designingbuildings.co.uk/w/index.php?title=Thermal_optical_properties&diff=87484&oldid=prev Editor at 11:11, 26 September 2017 2017-09-26T11:11:38Z

<p></p> <table style="background-color: white; color:black;"> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr valign='top'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 11:11, 26 September 2017</td> </tr><tr><td colspan="2" class="diff-lineno">Line 27:</td> <td colspan="2" class="diff-lineno">Line 27:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The continually changing position of the earth relative to the sun, and the diffusing nature of the atmosphere gives solar radiation incident upon the earth's surface a complex directional composition. For simplicity however, this is usually considered to consist of entirely diffuse, and entirely direct beam components. If the direct beam solar optical properties of a material are known for all angles of incidence, then its diffuse properties may be calculated by integration.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The continually changing position of the earth relative to the sun, and the diffusing nature of the atmosphere gives solar radiation incident upon the earth's surface a complex directional composition. For simplicity however, this is usually considered to consist of entirely diffuse, and entirely direct beam components. If the direct beam solar optical properties of a material are known for all angles of incidence, then its diffuse properties may be calculated by integration.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>= Long wave infra-red optical properties<del class="diffchange diffchange-inline">. </del>=</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>= Long wave infra-red optical properties =</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Most 'terrestrial' radiation occurs within the far or long wave infra-red wavebands. The wavelength of terrestrial radiation varies with temperature, however at room temperature approximately 97% of the radiation emanating from a perfect emitter will be within the range 3,000nm to 50,000nm.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Most 'terrestrial' radiation occurs within the far or long wave infra-red wavebands. The wavelength of terrestrial radiation varies with temperature, however at room temperature approximately 97% of the radiation emanating from a perfect emitter will be within the range 3,000nm to 50,000nm.</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 44:</td> <td colspan="2" class="diff-lineno">Line 44:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* g-value.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* g-value.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Heat transfer.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Heat transfer.</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">* Hygrothermal.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Light reflectance value.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Light reflectance value.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Low-e glass.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* Low-e glass.</div></td></tr> </table>

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