As shown in Figure 13, the extraterrestrial direct solar radiation
belonging to a particular location varies throughout the year.
The absorbed direct solar radiation
heat flux is shown as 
Three layers of construction materials were used to offset the effect of sol-air temperature resulting from direct solar radiation
. In addition, an extra floor was modeled on top of the first floor to eliminate the impact of geothermal heat.
(A) The direct solar radiation
component to the room is sensitive to the geometry of the rooms, zones and building.
The parameters include direct solar radiation
, ambient temperature, wind velocity, water temperature, air humidity, and mass flow rate.
According to ASHRAE, the new version incorporates seven published addenda to the 2013 edition and includes a new requirement to calculate the impact of direct solar radiation
on the thermal comfort of building occupants.
A combination of shading devices and clear type of glass provides the admission of daylight through the clear glass more than any other special type of glass, and protection for the window glass from any direct solar radiation
that might cause excessive solar heat gain.
Note also that a decrease in beam coefficient is often accompanied by an increase in diffuse coefficient due to enhanced scattering of incoming direct solar radiation
. Also, embedded in the representation of optical depth is the influence of elevation: higher locations tend to see less scattering and thus more direct solar radiation
They depend directly on the amount of direct solar radiation
for two air flow rates.
Figure 1(b) indicates that the diffuse solar radiation in Lhasa is similar to that in Beijing, while its direct solar radiation
is much higher than that in Beijing, causing the total solar radiation to be much higher than that in Beijing.
Described direct solar radiation
model was implemented as Matlab/Simulink block.