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Equation based model for calculating hourly solar radiation values

asked 8 years ago

Waseem's avatar

updated 5 years ago

Is there a simple but accurate model to calculate hourly solar radiation for a particular location by using other weather parameters and/or some constants? I would like to compare its accuracy with a developed model.

EDIT

I had a look at ASHREA model which states that the hourly global radiation (I), hourly beam radiation in the direction of rays (IN) and hourly diffuse radiation (Id) on the horizontal surface on a clear day are calculated as; I=INcosθz+Id IN=Aexp[B/cosθz] Id=CIN where, A,B,C are constants and θz is the zenith angle.

There is another model by Zhang Qingyuan et al; (@Joe Huang), which is of the form; I=[Io.sin(h).(c0+c1(CC)+c2(CC)2+c3(TnTn3)+c4ϕ+c5Vw)+d]/k where; I = estimated hourly solar radiation, Io = solar constant, h = solar altitude angle, CC = Cloud cover, ϕ= relative humidity, Tn = temperature at n hours, Vw= wind speed. and other are constants.

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@Joe Huang: maybe you could please throw some light and how/where to find all these constants and data source for cloud cover for a particular place. Thanks!

Waseem's avatar Waseem  ( 8 years ago )

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answered 8 years ago

Have you looked at the DOE2 model? When hourly solar data isn't available, DOE2 estimates the direct normal and diffuse radiation based on geometric data, a clearness number, and a cloud cover factor. It roughly corresponds to the algorithms SUN and CCF described in ASHRAE's Procedure for Determining Heating and Cooling Loads (1975). The algorithm is described on page III.21 of the DOE2.1A Engineer's manual. Not sure if it qualifies as simple. Parts of the model are also described in Chapter 14 of the 2013 ASHRAE Fundamentals handbook. You'll probably be able to find an appropriate model in Duffie and Beckman's Solar Engineering of Thermal Processes as well.

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Thanks, @aaron. I will have a look.

Waseem's avatar Waseem  ( 8 years ago )
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answered 5 years ago

cursin's avatar

I would recommend looking at this paper, it outlines a heap of different models including previously mentioned ones. https://www.mdpi.com/1996-1073/10/1/134

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Asked: 8 years ago

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Last updated: Sep 15 '16