For a horizontal surface, what fraction of the sky diffuse radiation does it receive? What fraction of the ground reflected radiation does it receive?For a horizontal surface, what fraction of the sky diffuse radiation does it receive? What fraction of the ground reflected radiation does it receive? Solution solution: 1)here first we must take look at factor which are included in total insolation on earth surface and this factor are direct,diffuse and reflected radiation. 2)as sun has emmisive power of 1367 w/m2 and out of which earth is receiving around 1120w/m2 as insolation 3)amount solar energy emitted moves along straight line path inside space but after entering atmosphere of earth,most part of this insolation moves along straigth path and strikes the earth and it is known as direct radiation,where remaining radiation are diffuse radiation and are formed due to scatering of direct beam of sunligth away from its path due to collision with molecule in its path. 4)on avearge clear sky ,direct radiation receive on horizontal surface are 85% of total insolation and diffuse radiation are only 15% of total insolation. 5)horizontal surface are one who collect all diffuse radiation than tilted one,hence horizontal surface receive diffuse radition of 15% only or 70 w/m2. 6)amount of reflected radiation are radiation reflected from earth surface and depend on material of object for blackbody it is zero,for lawn around 25% of total insolation and as horizontal surface and earth are parallel toeach other hence they have shape factor as 1 and total reflected radiation absorbed by plate..

1. For a horizontal surface, what fraction of the sky diffuse radiation does it receive? What fraction
of the ground reflected radiation does it receive?For a horizontal surface, what fraction of the sky
diffuse radiation does it receive? What fraction of the ground reflected radiation does it receive?
Solution
solution:
1)here first we must take look at factor which are included in total insolation on earth surface and
this factor are direct,diffuse and reflected radiation.
2)as sun has emmisive power of 1367 w/m2 and out of which earth is receiving around
1120w/m2 as insolation
3)amount solar energy emitted moves along straight line path inside space but after entering
atmosphere of earth,most part of this insolation moves along straigth path and strikes the earth
and it is known as direct radiation,where remaining radiation are diffuse radiation and are formed
due to scatering of direct beam of sunligth away from its path due to collision with molecule in
its path.
4)on avearge clear sky ,direct radiation receive on horizontal surface are 85% of total insolation
and diffuse radiation are only 15% of total insolation.
5)horizontal surface are one who collect all diffuse radiation than tilted one,hence horizontal
surface receive diffuse radition of 15% only or 70 w/m2.
6)amount of reflected radiation are radiation reflected from earth surface and depend on material
of object for blackbody it is zero,for lawn around 25% of total insolation and as horizontal
surface and earth are parallel toeach other hence they have shape factor as 1 and total reflected
radiation absorbed by plate.