Physical Model, Real Sky Outdoor Testing: Integrated Illumination
This mode of physical model testing is the most complex and involves taking the model, measurement and video equipment described above outdoors into real sky conditions. While the measurement and observational procedures are essentially the same as in the test types above, testing must be coordinated to coincide with desired, stable and favorable weather and sky conditions. To simulate proper solar geometries in relation to the model it is twisted and tipped in relation to the (moving) sun to simulate different times of the day, month and year to be studied. This tipping, if extreme, compromises the model’s simultaneous exposure to the sky vault by partially exposing it to the testing site’s ground plane instead. This also can compromise the proper consideration of the ground reflectance component. The surrounding context of the testing site, if significantly different from that of the proposed building site can also be influential. During the course of the test, measurements are collected as quickly as possible to minimize the influence of changing sky conditions . Results from this testing are very accurate for the times and conditions tested but it is often difficult to test under representative conditions.