Different faces of the sun

“The sun has two different faces. The kind face of the sun appears in cold times; and its unkind face appears in hot times. In according to the properties of each location, kind and unkind faces of the sun differ from place to place, these local faces of the sun more than whatever depend on two parameters: 1st, the intensity of direct and diffused solar radiation in each moment; 2nd, the amount of need to shade or shine in according to the difference between comfortable temperature and outdoor temperature in each moment. [1, 61-91] & [2,1]”

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Fig. 2. Defining kind and unkind faces of the sun (desirability/undesirability of direct radiation) in the city of Yazd[31.5N, 54.2E] using 21°C as the base: 0.01 * radiation received x (21°C — outdoor temperature)

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However other parameters such as wind and humidity have important roles in comfort condition, we decide not to apply them here to see the major effect of parameters of position of the sun, its total radiation and the changes in temperature through the day and in each month.

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Fig. 3. Different faces of the sun in different cities of Iran

 

In Ramsar[36.9N, 50.7E] cloudy weather and low changes in temperature from the sunrise to the sunset and through the year is the reason why the level of kind and unkind faces of the sun is low. Hamedan[34.8N, 48.6,E] and Tabas[33.6N 56.9E] are almost on the same latitude but Hamedan has cold climate and Tabas is hot. Shiraz[29.7N 53E] has two hot and cold conditions so in this city the kind and unkind faces of the sun has high levels.

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