While it's hard to find a major change in any one area, there are numerous changes spread across the performance, handling, aero, braking and comfort envelope
that make the 650S a more focused, sharper, and a more comfortable drive than the 12C.
Using the SET program, I found that when calculating the comfort zones with an air speed of 70 fpm (0.35 m/s), the comfort envelope
moves to the right less than the thickness of the line defining the comfort zone!
A simple control strategy that will work year-round (and will change with the weather) is to open windows when outdoor conditions fall within the ASHRAE Standard 55-2010 adaptive comfort envelope
and to close windows when indoor conditions are approaching the boundaries of the comfort envelope
Comfort envelope. Starting with these still-air zones, 0.5 and 1.0 clo comfort envelopes for air speeds above 0.15 m/s (30 fpm) are generated using the SET model.
"Ceiling fans as extenders of the summer comfort envelope." ASHRAE Transactions 89(1):245 -263.
Starting with this range, comfort envelopes
are defined using the work of Nicol (2004) on air movement: when the air velocity is above 0.1m/s, the comfort temperature can be raised according to Eq.