I put together a simple static model of an ECAT type of device and a few
vorticians were interesting in how it performed. One of these, Osmo Laaksonen,
took my very simple model and improved it as well as offered a link to it for
anyone to download. He has taken an ideal model of a type 2 design and
produced several important graphs that demonstrate how a system of this type
behaves.
It should be noted that the device modeled is stable at any input power
although it contains a negative resistance region. Of course, you will not be
able to set the input to a fixed power level that results in static operation
within that special region. You will however be able to remove the input drive
and observe that the device cools back to ambient after it goes through a
transient condition.
Osmo chose parameters that are closer to those seen in a real device although
we do not have adequate data to verify that this particular design is possible.
The geometry and the behavior of the fuel are key ingredients that have not
been well analyzed thus far.
You will find that the device graphed obeys the two general rules that I
established earlier for an input controllable positive feedback thermal system
with reasonable power gain. First, there exists no temperature within the
region of operation where the internally generated power exceeds the power
being radiated, conducted, and convected into the ambient. This ensures that
no latch up condition occurs during operation. Also, the slope of the input
power versus device temperature contains a negative region. This results in a
negative resistance region which is desired in order to maintain a good COP.
The spreadsheet can be downloaded at:
https://docs.google.com/spreadsheets/d/1-a6DVROpImcdbLm7YQLe5cY3ZThm_k7wgJHc531Psgo/edit?usp=sharing
I recommend that you download the file and take a close look at what it
displays. This type of characterization appears to enhance ones understanding
of how this type of system operates and will guide the designs toward optimum
results. Please direct any questions to me.
Dave
