Using unshaded pyranometer for measuring solar radiation components - PowerPoint PPT Presentation

Using unshaded pyranometer for measuring solar radiation components in the automatic mode Zuev S. V. zuev@imces.ru Institute of Monitoring of Climatic and Ecological Systems SB RAS Russia, 634055, Tomsk, 10/3, Academichesky ave.

Shotwave radiation balance S 0 =1367 W/m ² 99 % λ =0,17-4,0 µ m B k = Q k - R k Q k = S` + D

Standard methods for measurement of total solar radiation Q Q k = D Q k = S` + D Q k = ( Q`-D)·K h ·K a + D

Shortcomings of standard methods • 6 measurements once a day; • requires two devices; • requires human presence or sun tracker.

Using unshaded pyranometer The practice of using unshaded pyranometer for measurement of total solar radiation Q k in automatic mode . Pyranometer CM-11 Kipp & Zonen. Measurement error ≤ 3%. Price 2400 €

Using unshaded pyranometer Pyranometer М -115 М . Measurement error ≤ 15-20% depending on the altitude and azimuth of the sun

Correction of the measured total solar radiation Q k = S` + D - for CM-11 Q k = S`·K h ·K a + D - for М -115 М Using clouds like shade disk for unshaded pyranometer ( Q k = D) for separation of total solar radiation Q on components S` and D

Estimation of direct S` and diffuse D radiations

Estimation of direct S` and diffuse D radiations

Estimation of direct S` and diffuse D radiations

Estimation of direct S` and diffuse D radiations

Estimation of direct S` and diffuse D radiations Q k = S`·K h ·K a + D Q k = S` + D

Duration of solar irradiation Time when S ≥ 140 W/m 2

Estimation of solar irradiation duration using unshaded pyranometer

Atmospheric transmission coefficient S P , 30 ρ ° = • using the Bouguér formula S 0 • using the special tabs

Atmospheric turbidity coefficient S T 11 , 5 lg • using the Linke formula 0 = S , 30 ρ ° • using the special tabs

Solar radiation characteristics defined by unshaded piranometer • total solar radiation Q ; • direct solar radiation S` ; • diffuse solar radiation D ; • duration of solar irradiation; • atmospheric transmission coefficient P ; • atmospheric turbidity coefficient T .

Using unshaded pyranometer for measuring solar radiation components in the automatic mode Zuev S. V. zuev@imces.ru Institute of Monitoring of Climatic and Ecological Systems SB RAS Russia, 634055, Tomsk, 10/3, Academichesky ave.