On Tue, 17 Aug 2004 13:10:19 +0300, Paul Keinanen
wrote:

First of all, the test should not be run for 5 minutes, but until a
thermal equilibrium inside the container has been established,
possibly mixing the air inside the container with a fan.

Hi Paul,

First, you show that this is not an intractable problem, merely one
that requires care. Good work.

However, as to the statement above, and the presumptions that follow,
there is no equilibrium to observe as the test implementation has been
described. You are pouring calories into an insulated environment
which can only raise temperature without end (short of destruction, of
course).

As I described elsewhere, this is called a caloric bomb, and as such
should be limited in time for all comparisons. What you are
describing requires a steady flow of coolant through the chamber where
you measure the inlet and exhaust temperatures and use THAT
differential. Care must be given to not exhaust into the inlet, and
to maintain the inlet with a body of constant temperature air (to
simplify matters).

The problem is not really that difficult - it only takes attention to
detail such as your response indicates.

73's
Richard Clark, KB7QHC