Direct Beam and Diffuse Spectral Irradiance Measurements in a Nordic Country Analyzed With the Average Photon Energy Parameter

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One year of spectrally resolved direct normal irradiance (DNI), diffuse horizontal irradiance (DfHI) and global horizontal irradiance (GHI) measured in Roskilde, Denmark are analyzed in terms of the average photon energy (APE). We show that the APE of the GHI component is characterized by spectral distributions with low standard deviations, which is consistent with the findings of previous authors. In contrast, the APE of the DfHI and DNI components show spectral distributions with higher standard deviations, which suggests that a given APE value for DNI or DfHI can represent a wider array of spectral distributions. Finally, it is shown that the DfHI APE is characterized by high energy spectral distributions, which has particular significance in the case of building integrated photovoltaic (BIPV) applications in Nordic countries.
Original languageEnglish
Title of host publicationProceedings of 7th World Conference on Photovoltaic Energy Conversion
Number of pages6
Publication date2018
Publication statusPublished - 2018
Event7th World Conference on Photovoltaic Energy Conversion - Hilton Waikoloa Village Resort, Waikoloa, United States
Duration: 10 Jun 201815 Jun 2018
Conference number: WCPEC-7


Conference7th World Conference on Photovoltaic Energy Conversion
LocationHilton Waikoloa Village Resort
CountryUnited States


  • Average Photon Energy
  • BIPV

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