Final answer:
In Physics, the facade azimuth affects the amount of direct sunlight a surface receives, with south-facing facades (in the Northern Hemisphere) receiving more sunlight. This principle is used advantageously in building design to manage heat gain, and in the optimal placement of solar collectors to maximize sunlight capture.
Step-by-step explanation:
The question whether a vertical facade receives more direct sunlight as its facade azimuth decreases pertains to the field of Physics, specifically to the study of solar irradiance and architectural design. When designing buildings, especially concerning the placement and size of windows, understanding the sun's path and solar exposure is crucial. As the facade azimuth angles towards the south, it generally receives more direct sunlight, particularly in the Northern Hemisphere. This is due to the sun's apparent motion being southernly from most locations north of the equator.
In cases such as hot sunny climates like Texas or Arizona, to avoid excessive heat gain, it is favorable for the largest windows to face north, and for south-facing walls to be well insulated with smaller windows that facilitate cross-ventilation without letting in much sunlight. The consideration of facade orientation and the optimization of thermal comfort are vital for the energy efficiency and comfort within a building. Solar collectors, on the other hand, are designed to maximize sunlight capture and hence they always face south with a tilt close to the latitude angle to stay as perpendicular to the sun's rays as possible, hence catching the maximum amount of sunlight for heating water or generating electricity.