Abstract

A ray tracing algorithm has been developed to model solar radiation interaction with complex urban environments and, in particular, its effects, including the total irradiance on each surface and overall dissipated power contribution. The proposed model accounts for multiple reflection and diffuse scattering interactions and is based on a rigorous theory, so that the overall power balance is satisfied at the generic surface element. Such approach is validated against measurements in the present work in simple reference scenarios. The results show the importance of multiple-bounce interactions and diffuse scattering to obtain reliable solar irradiance and heat dissipation estimates in urban areas.

© 2014 Optical Society of America

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References

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  1. L. Howard, The Climate Of London, Deduced From Meteorological Observations, Made at Different Places in the Neighbourhood of the Metropolis (W. Phillips, 1818), Vol. 2.
  2. H. E. Landsberg, The Urban Climate (Academic, 1981).
  3. H. Taha, “Urban climates and heat islands: albedo, evapotranspiration, and anthropogenic heat,” Energy Build. 25, 99–103 (1997).
    [CrossRef]
  4. “Urban heat island basics,” in Reducing Urban Heat Islands: Compendium of Strategies, http://www.epa.gov/heatisland/ .
  5. http://heatisland.lbl.gov/ .
  6. http://www.envi-met.com/ .
  7. S. Huttner, M. Bruse, and P. Dostal, “Using ENVI-met to simulate the impact of global warming on the microclimate in central European cities,” in 5th Japanese-German Meeting on Urban Climatology, H. Mayer and A. Matzarakis, eds., (2008), pp. 307–312.
  8. http://www.urbanclimate.net/rayman/ .
  9. A. Matzarakis, F. Rutz, and H. Mayer, “Modelling radiation fluxes in simple and complex environments—application of the RayMan model,” Int. J. Biometeorol. 51, 323–334 (2007).
    [CrossRef]
  10. M. Iqbal, An Introduction to Solar Radiation (Academic, 1983).
  11. T. Muneer, Solar Radiation and Daylight Models, 2nd ed. (Elsevier, 2004).
  12. D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
    [CrossRef]
  13. V. Degli-Esposti, D. Guiducci, A. de’ Marsi, P. Azzi, and F. Fuschini, “An advanced field prediction model including diffuse scattering,” IEEE Trans. Antennas Propag. 52, 1717–1728 (2004).
    [CrossRef]
  14. V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Speed-up techniques for ray tracing field prediction models,” IEEE Trans. Antennas Propag. 57, 1469–1480 (2009).
    [CrossRef]
  15. V. Degli-Esposti, “A diffuse scattering model for urban propagation prediction,” IEEE Trans. Antennas Propag. 49, 1111–1113 (2001).
    [CrossRef]
  16. V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Measurement and modelling of scattering from buildings,” IEEE Trans. Antennas Propag. 55, 143–153 (2007).
    [CrossRef]
  17. E. M. Vitucci, V. Degli-Esposti, and L. Capriotti, “Ray tracing to predict insolation in urban environment,” in IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Munich, Germany, 22–27 July2012.
  18. J. A. Duffie and W. A. Beckmann, Solar Engineering of Thermal Processes, 2nd ed. (Wiley, 2006).
  19. P. G. Loutzenhiser, H. Manz, C. Felsmann, P. A. Strachan, T. Frank, and G. M. Maxwell, “Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation,” Solar Energy 81, 254–267 (2007).
    [CrossRef]
  20. http://eosweb.larc.nasa.gov/ .
  21. M. Iqbal, “Prediction of hourly diffuse solar radiation from measured hourly global radiation on a horizontal surface,” Solar Energy 24, 491–503 (1980).
    [CrossRef]
  22. http://www.solaritaly.enea.it .
  23. B. Hapke, Theory of Reflectance and Emittance Spectroscopy (Cambridge University, 1993).
  24. J. A. Cockley, “Reflectance and albedo, surface,” in Encyclopedia of Atmospheric Sciences, J. Holton, J. Pyle, and J. Curry, eds., (Elsevier, Academic, 2003).
  25. F. Kreith and R. E. West, CRC Handbook of Energy Efficiency (CRC Press, 1996).
  26. United States Environmental Protection Agency, “Cooling our communities: a guidebook on tree planting and light-colored surfaces,” (Office of Policy Analysis, Climate Change Division, Washington, DC).

2009 (1)

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Speed-up techniques for ray tracing field prediction models,” IEEE Trans. Antennas Propag. 57, 1469–1480 (2009).
[CrossRef]

2007 (3)

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Measurement and modelling of scattering from buildings,” IEEE Trans. Antennas Propag. 55, 143–153 (2007).
[CrossRef]

P. G. Loutzenhiser, H. Manz, C. Felsmann, P. A. Strachan, T. Frank, and G. M. Maxwell, “Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation,” Solar Energy 81, 254–267 (2007).
[CrossRef]

A. Matzarakis, F. Rutz, and H. Mayer, “Modelling radiation fluxes in simple and complex environments—application of the RayMan model,” Int. J. Biometeorol. 51, 323–334 (2007).
[CrossRef]

2004 (1)

V. Degli-Esposti, D. Guiducci, A. de’ Marsi, P. Azzi, and F. Fuschini, “An advanced field prediction model including diffuse scattering,” IEEE Trans. Antennas Propag. 52, 1717–1728 (2004).
[CrossRef]

2001 (2)

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

V. Degli-Esposti, “A diffuse scattering model for urban propagation prediction,” IEEE Trans. Antennas Propag. 49, 1111–1113 (2001).
[CrossRef]

1997 (1)

H. Taha, “Urban climates and heat islands: albedo, evapotranspiration, and anthropogenic heat,” Energy Build. 25, 99–103 (1997).
[CrossRef]

1980 (1)

M. Iqbal, “Prediction of hourly diffuse solar radiation from measured hourly global radiation on a horizontal surface,” Solar Energy 24, 491–503 (1980).
[CrossRef]

Azzi, P.

V. Degli-Esposti, D. Guiducci, A. de’ Marsi, P. Azzi, and F. Fuschini, “An advanced field prediction model including diffuse scattering,” IEEE Trans. Antennas Propag. 52, 1717–1728 (2004).
[CrossRef]

Beckmann, W. A.

J. A. Duffie and W. A. Beckmann, Solar Engineering of Thermal Processes, 2nd ed. (Wiley, 2006).

Bruse, M.

S. Huttner, M. Bruse, and P. Dostal, “Using ENVI-met to simulate the impact of global warming on the microclimate in central European cities,” in 5th Japanese-German Meeting on Urban Climatology, H. Mayer and A. Matzarakis, eds., (2008), pp. 307–312.

Buhl, W. F.

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

Capriotti, L.

E. M. Vitucci, V. Degli-Esposti, and L. Capriotti, “Ray tracing to predict insolation in urban environment,” in IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Munich, Germany, 22–27 July2012.

Cockley, J. A.

J. A. Cockley, “Reflectance and albedo, surface,” in Encyclopedia of Atmospheric Sciences, J. Holton, J. Pyle, and J. Curry, eds., (Elsevier, Academic, 2003).

Crawley, D. B.

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

de’ Marsi, A.

V. Degli-Esposti, D. Guiducci, A. de’ Marsi, P. Azzi, and F. Fuschini, “An advanced field prediction model including diffuse scattering,” IEEE Trans. Antennas Propag. 52, 1717–1728 (2004).
[CrossRef]

Degli-Esposti, V.

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Speed-up techniques for ray tracing field prediction models,” IEEE Trans. Antennas Propag. 57, 1469–1480 (2009).
[CrossRef]

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Measurement and modelling of scattering from buildings,” IEEE Trans. Antennas Propag. 55, 143–153 (2007).
[CrossRef]

V. Degli-Esposti, D. Guiducci, A. de’ Marsi, P. Azzi, and F. Fuschini, “An advanced field prediction model including diffuse scattering,” IEEE Trans. Antennas Propag. 52, 1717–1728 (2004).
[CrossRef]

V. Degli-Esposti, “A diffuse scattering model for urban propagation prediction,” IEEE Trans. Antennas Propag. 49, 1111–1113 (2001).
[CrossRef]

E. M. Vitucci, V. Degli-Esposti, and L. Capriotti, “Ray tracing to predict insolation in urban environment,” in IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Munich, Germany, 22–27 July2012.

Dostal, P.

S. Huttner, M. Bruse, and P. Dostal, “Using ENVI-met to simulate the impact of global warming on the microclimate in central European cities,” in 5th Japanese-German Meeting on Urban Climatology, H. Mayer and A. Matzarakis, eds., (2008), pp. 307–312.

Duffie, J. A.

J. A. Duffie and W. A. Beckmann, Solar Engineering of Thermal Processes, 2nd ed. (Wiley, 2006).

Falciasecca, G.

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Speed-up techniques for ray tracing field prediction models,” IEEE Trans. Antennas Propag. 57, 1469–1480 (2009).
[CrossRef]

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Measurement and modelling of scattering from buildings,” IEEE Trans. Antennas Propag. 55, 143–153 (2007).
[CrossRef]

Felsmann, C.

P. G. Loutzenhiser, H. Manz, C. Felsmann, P. A. Strachan, T. Frank, and G. M. Maxwell, “Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation,” Solar Energy 81, 254–267 (2007).
[CrossRef]

Fisher, D. E.

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

Frank, T.

P. G. Loutzenhiser, H. Manz, C. Felsmann, P. A. Strachan, T. Frank, and G. M. Maxwell, “Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation,” Solar Energy 81, 254–267 (2007).
[CrossRef]

Fuschini, F.

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Speed-up techniques for ray tracing field prediction models,” IEEE Trans. Antennas Propag. 57, 1469–1480 (2009).
[CrossRef]

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Measurement and modelling of scattering from buildings,” IEEE Trans. Antennas Propag. 55, 143–153 (2007).
[CrossRef]

V. Degli-Esposti, D. Guiducci, A. de’ Marsi, P. Azzi, and F. Fuschini, “An advanced field prediction model including diffuse scattering,” IEEE Trans. Antennas Propag. 52, 1717–1728 (2004).
[CrossRef]

Glazer, J.

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

Guiducci, D.

V. Degli-Esposti, D. Guiducci, A. de’ Marsi, P. Azzi, and F. Fuschini, “An advanced field prediction model including diffuse scattering,” IEEE Trans. Antennas Propag. 52, 1717–1728 (2004).
[CrossRef]

Hapke, B.

B. Hapke, Theory of Reflectance and Emittance Spectroscopy (Cambridge University, 1993).

Howard, L.

L. Howard, The Climate Of London, Deduced From Meteorological Observations, Made at Different Places in the Neighbourhood of the Metropolis (W. Phillips, 1818), Vol. 2.

Huang, Y. J.

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

Huttner, S.

S. Huttner, M. Bruse, and P. Dostal, “Using ENVI-met to simulate the impact of global warming on the microclimate in central European cities,” in 5th Japanese-German Meeting on Urban Climatology, H. Mayer and A. Matzarakis, eds., (2008), pp. 307–312.

Iqbal, M.

M. Iqbal, “Prediction of hourly diffuse solar radiation from measured hourly global radiation on a horizontal surface,” Solar Energy 24, 491–503 (1980).
[CrossRef]

M. Iqbal, An Introduction to Solar Radiation (Academic, 1983).

Kreith, F.

F. Kreith and R. E. West, CRC Handbook of Energy Efficiency (CRC Press, 1996).

Landsberg, H. E.

H. E. Landsberg, The Urban Climate (Academic, 1981).

Lawrie, L. K.

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

Liesen, R. J.

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

Loutzenhiser, P. G.

P. G. Loutzenhiser, H. Manz, C. Felsmann, P. A. Strachan, T. Frank, and G. M. Maxwell, “Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation,” Solar Energy 81, 254–267 (2007).
[CrossRef]

Manz, H.

P. G. Loutzenhiser, H. Manz, C. Felsmann, P. A. Strachan, T. Frank, and G. M. Maxwell, “Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation,” Solar Energy 81, 254–267 (2007).
[CrossRef]

Matzarakis, A.

A. Matzarakis, F. Rutz, and H. Mayer, “Modelling radiation fluxes in simple and complex environments—application of the RayMan model,” Int. J. Biometeorol. 51, 323–334 (2007).
[CrossRef]

Maxwell, G. M.

P. G. Loutzenhiser, H. Manz, C. Felsmann, P. A. Strachan, T. Frank, and G. M. Maxwell, “Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation,” Solar Energy 81, 254–267 (2007).
[CrossRef]

Mayer, H.

A. Matzarakis, F. Rutz, and H. Mayer, “Modelling radiation fluxes in simple and complex environments—application of the RayMan model,” Int. J. Biometeorol. 51, 323–334 (2007).
[CrossRef]

Muneer, T.

T. Muneer, Solar Radiation and Daylight Models, 2nd ed. (Elsevier, 2004).

Pedersen, C. O.

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

Rutz, F.

A. Matzarakis, F. Rutz, and H. Mayer, “Modelling radiation fluxes in simple and complex environments—application of the RayMan model,” Int. J. Biometeorol. 51, 323–334 (2007).
[CrossRef]

Strachan, P. A.

P. G. Loutzenhiser, H. Manz, C. Felsmann, P. A. Strachan, T. Frank, and G. M. Maxwell, “Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation,” Solar Energy 81, 254–267 (2007).
[CrossRef]

Strand, R. K.

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

Taha, H.

H. Taha, “Urban climates and heat islands: albedo, evapotranspiration, and anthropogenic heat,” Energy Build. 25, 99–103 (1997).
[CrossRef]

Vitucci, E. M.

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Speed-up techniques for ray tracing field prediction models,” IEEE Trans. Antennas Propag. 57, 1469–1480 (2009).
[CrossRef]

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Measurement and modelling of scattering from buildings,” IEEE Trans. Antennas Propag. 55, 143–153 (2007).
[CrossRef]

E. M. Vitucci, V. Degli-Esposti, and L. Capriotti, “Ray tracing to predict insolation in urban environment,” in IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Munich, Germany, 22–27 July2012.

West, R. E.

F. Kreith and R. E. West, CRC Handbook of Energy Efficiency (CRC Press, 1996).

Winkelmann, F. C.

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

Witte, M. J.

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

Energy Build. (2)

H. Taha, “Urban climates and heat islands: albedo, evapotranspiration, and anthropogenic heat,” Energy Build. 25, 99–103 (1997).
[CrossRef]

D. B. Crawley, L. K. Lawrie, F. C. Winkelmann, W. F. Buhl, Y. J. Huang, C. O. Pedersen, R. K. Strand, R. J. Liesen, D. E. Fisher, M. J. Witte, and J. Glazer, “EnergyPlus: creating a new-generation building energy simulation program,” Energy Build. 33, 319–331 (2001).
[CrossRef]

IEEE Trans. Antennas Propag. (4)

V. Degli-Esposti, D. Guiducci, A. de’ Marsi, P. Azzi, and F. Fuschini, “An advanced field prediction model including diffuse scattering,” IEEE Trans. Antennas Propag. 52, 1717–1728 (2004).
[CrossRef]

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Speed-up techniques for ray tracing field prediction models,” IEEE Trans. Antennas Propag. 57, 1469–1480 (2009).
[CrossRef]

V. Degli-Esposti, “A diffuse scattering model for urban propagation prediction,” IEEE Trans. Antennas Propag. 49, 1111–1113 (2001).
[CrossRef]

V. Degli-Esposti, F. Fuschini, E. M. Vitucci, and G. Falciasecca, “Measurement and modelling of scattering from buildings,” IEEE Trans. Antennas Propag. 55, 143–153 (2007).
[CrossRef]

Int. J. Biometeorol. (1)

A. Matzarakis, F. Rutz, and H. Mayer, “Modelling radiation fluxes in simple and complex environments—application of the RayMan model,” Int. J. Biometeorol. 51, 323–334 (2007).
[CrossRef]

Solar Energy (2)

M. Iqbal, “Prediction of hourly diffuse solar radiation from measured hourly global radiation on a horizontal surface,” Solar Energy 24, 491–503 (1980).
[CrossRef]

P. G. Loutzenhiser, H. Manz, C. Felsmann, P. A. Strachan, T. Frank, and G. M. Maxwell, “Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation,” Solar Energy 81, 254–267 (2007).
[CrossRef]

Other (17)

http://eosweb.larc.nasa.gov/ .

http://www.solaritaly.enea.it .

B. Hapke, Theory of Reflectance and Emittance Spectroscopy (Cambridge University, 1993).

J. A. Cockley, “Reflectance and albedo, surface,” in Encyclopedia of Atmospheric Sciences, J. Holton, J. Pyle, and J. Curry, eds., (Elsevier, Academic, 2003).

F. Kreith and R. E. West, CRC Handbook of Energy Efficiency (CRC Press, 1996).

United States Environmental Protection Agency, “Cooling our communities: a guidebook on tree planting and light-colored surfaces,” (Office of Policy Analysis, Climate Change Division, Washington, DC).

E. M. Vitucci, V. Degli-Esposti, and L. Capriotti, “Ray tracing to predict insolation in urban environment,” in IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Munich, Germany, 22–27 July2012.

J. A. Duffie and W. A. Beckmann, Solar Engineering of Thermal Processes, 2nd ed. (Wiley, 2006).

M. Iqbal, An Introduction to Solar Radiation (Academic, 1983).

T. Muneer, Solar Radiation and Daylight Models, 2nd ed. (Elsevier, 2004).

L. Howard, The Climate Of London, Deduced From Meteorological Observations, Made at Different Places in the Neighbourhood of the Metropolis (W. Phillips, 1818), Vol. 2.

H. E. Landsberg, The Urban Climate (Academic, 1981).

“Urban heat island basics,” in Reducing Urban Heat Islands: Compendium of Strategies, http://www.epa.gov/heatisland/ .

http://heatisland.lbl.gov/ .

http://www.envi-met.com/ .

S. Huttner, M. Bruse, and P. Dostal, “Using ENVI-met to simulate the impact of global warming on the microclimate in central European cities,” in 5th Japanese-German Meeting on Urban Climatology, H. Mayer and A. Matzarakis, eds., (2008), pp. 307–312.

http://www.urbanclimate.net/rayman/ .

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Figures (20)

Fig. 1.
Fig. 1.

Example of solar path during a day.

Fig. 2.
Fig. 2.

Virtual emitters placed on a hemispherical surface to emulate the diffuse solar radiation.

Fig. 3.
Fig. 3.

Power balance at the generic surface element: Pi, Pr, Pp, Ps, Pth, and Pd are the incident, reflected, penetrated, scattered, thermal-emission, and dissipated powers, respectively.

Fig. 4.
Fig. 4.

Block diagram of solar RT model.

Fig. 5.
Fig. 5.

Example of dissipated energy map obtained with the solar RT model. Total radiation absorbed by building walls, roofs, windows, and ground during a summer day (in July) is represented for an urban area (location: Castelnovo ne’ Monti, Italy, Lat: 44° 26 11, 40 N; Long: 10° 24 15, 48 E).

Fig. 6.
Fig. 6.

Reference-grade solar lamp.

Fig. 7.
Fig. 7.

Response pattern of the solar meter. The lobes are narrower than those of a Lambertian cosine-shaped pattern.

Fig. 8.
Fig. 8.

Measurement environment for case (a). A similar arrangement was adopted for the other cases.

Fig. 9.
Fig. 9.

Plaster surfaces for cases (a)–(c).

Fig. 10.
Fig. 10.

Case (a): Measurement and simulations result with different reflectivity values.

Fig. 11.
Fig. 11.

Case (a): Measurement and simulations result with different scattering coefficient (S) values.

Fig. 12.
Fig. 12.

Case (a): Measurement and simulations result with different α values.

Fig. 13.
Fig. 13.

Case (a): Measurement and simulations result with different ray interactions.

Fig. 14.
Fig. 14.

Case (a): Further validation results for afternoon hours.

Fig. 15.
Fig. 15.

Case (b): Measurement and simulations result with optimum parameters (albedo and scattering coefficient), Lambertian scattering pattern, 1 reflection + 1 scattering.

Fig. 16.
Fig. 16.

Case (c): Measurement and simulations result with optimum parameters (albedo and scattering coefficient), Lambertian scattering pattern, 1 reflection + 1 scattering.

Fig. 17.
Fig. 17.

Incident energy density (insolation) obtained through RT simulations in proximity of the building of measurement scenario (a).

Fig. 18.
Fig. 18.

Representation of solar rays incident and reflected/backscattered from a solar blind with curved blades.

Fig. 19.
Fig. 19.

Representation of the transmittance of a solar blind with curved blades as a function of the incidence angles (azimuth, elevation) of solar rays in the case of horizontally oriented blades.

Fig. 20.
Fig. 20.

Total heat-dissipated energy along 100 m of an urban street canyon for different orientations and street/building sizes. Location: Cesena, north Italy (Lat: 44° 9 25, 56 N; Long: 12° 15 54, 00 E).

Tables (3)

Tables Icon

Table 1. Behavior of Direct and Diffuse Horizontal Irradiance for Different Weather Conditions (Northern Hemisphere, Latitudes: 35°–55°)

Tables Icon

Table 2. Typical Albedo Values for Different Categories of Materials in Urban Environment [25,26]

Tables Icon

Table 3. Relative Reduction in Heat-Dissipated Power Using Oblique Street Orientation with Respect to Worst Case (East/West Street Orientation) in Different Cases and Regions

Equations (15)

Equations on this page are rendered with MathJax. Learn more.

G0_norm=SC·[1+0.034cos(360·n365)][W/m2].
G0_tilted=G0_norm·cos(θ)[W/m2].
G0=G0_norm·cos(z),
kt=G¯G¯0=G¯b+G¯dG¯0,
kd=G¯dG¯=G¯dG¯b+G¯d.
Gb=GGd=G0·kt·(1kd)[W/m2].
Gd=G0·kt·kd[W/m2].
kd=0.9580.982·kt.
Pi=Pr+Pp+Ps+Pd.
p=E22η=PΔs[W/m2],
pr=ΓR2pi,
ps=S2pr,
R=1S2.
Pd=Pd+Pp=PiPrPs,
𝒫(ψR)=(1+cosψR2)α,

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