Following up on the research Neil is doing to see if there is cooler air
under the van available to be ducted up to cool the radiator fins on the
back of the Dometic refrigerator, I did some measurements which model
the way I use Mellow Yellow when we go camping during warm weather

Test Conditions.
The van was not moved for several days, so that the ground was not
retaining warmth from solar heating. Poptop up, doors and windows open,
zips all unzipped. This is pretty much how we camp.

Instrumentation.
My handy Oregon Scientific 433MHz wireless indoor/outdoor thermometer
with the plastic picture frame which still has the picture of the
unknown couple that it had when I bought it.

Procedure.
Thermometer sender leaned against cabinet below refrigerator, and
allowed 15 minutes to stabilize before reading, then  moved under center
of van and placed atop a block of wood to elevate it a few inches above
the pavement, stabilized for 15 minutes, and reading taken.

Results.
Reading one, midmorning, 11am, van in full shade. Inside at floor level:
76F; underneath van at ground level: 76F
Reading two: mid afternoon, 3pm, van in full sun. Inside at floor level:
82F; underneath van at ground level: 81F

Conclusion.
Under these conditions, there is not a significant difference in
temperature. Anyone who camps like we do, with their windows and zips
all open during the day, should not count on finding cooler air under
the van.

--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR