Page 126 - GRIHA Manual Volume III - Introduction to National Rating System
P. 126
Annexures 119
AnnexuRe-4
Method for Horizontal Shadow Angle (HSA) and Vertical
Shadow Angle (VSA) calculation
Since the primary objective of any shading device is to reduce direct solar radiation throughout
summer, it is important to optimize the shading depth that can cut the sun angle of the peak incident
radiation. Therefore, the first step is to calculate the shadow angles on highest summer radiant days.
Calculation of HSA and VSA by using software simulation
The sun path analysis by using software simulation resulted in the sun path diagram of the selected
surface of the building and tabulated solar data for the selected day from sunrise to sunset. From
this tabulated data, the critical HSA and VSA can be easily established for any date of the year and
any hour of the day.
Example: Calculate the critical HSA and VSA of one of the southern façade of building situated at
New Delhi on 1 April at 12 o’clock.
Figure 1 Sun path diagram
For calculating HSA & VSA using shadow angle protractor, refer climatology_part-1_SP41.
AnnexuRe-4
Method for Horizontal Shadow Angle (HSA) and Vertical
Shadow Angle (VSA) calculation
Since the primary objective of any shading device is to reduce direct solar radiation throughout
summer, it is important to optimize the shading depth that can cut the sun angle of the peak incident
radiation. Therefore, the first step is to calculate the shadow angles on highest summer radiant days.
Calculation of HSA and VSA by using software simulation
The sun path analysis by using software simulation resulted in the sun path diagram of the selected
surface of the building and tabulated solar data for the selected day from sunrise to sunset. From
this tabulated data, the critical HSA and VSA can be easily established for any date of the year and
any hour of the day.
Example: Calculate the critical HSA and VSA of one of the southern façade of building situated at
New Delhi on 1 April at 12 o’clock.
Figure 1 Sun path diagram
For calculating HSA & VSA using shadow angle protractor, refer climatology_part-1_SP41.
