Horace Heffner wrote:
However, because T2 readings can not be trusted, we don't even know if the steam temperature is 120°C.Not sure why we cannot trust the T2 readings. I must have missed that.
Maybe we can trust the value, but what does it MEAN?
The Lewan's September results showed 120C, 50% water -- implying either a mix of superheated steam and overflow (unlikely with this architecture, where it overflows from the top), or 2 Bar pressure, or a thermocouple placed so close to the core/fins that it's not reading the steam/water temperature.
** nonproportional font required **** My September guess :
Port | | *------------------------------* *----* | Superheated 1 Bar | | | | Steam 118C ==> | | outlet hose 95% Dry | *------------------------ 1 Bar 100C | ^ *=====================* Superheated steam =====> Steam | | | CORE | 118C |~~~~~| |~~~~~~~~~~~~~~~~~~~~~~~ overflow fluid 100C | | | *---------* ~ *----- | *=====================* | | ~ | ~~~~~ ====| Water | | ~ | Inlet | Boil 100C | Water Trap 100C : : *--------------------------------------*
The left side was a good guess ... with the core in the middle and fins above and below.
The right side was wrong, because the outlet is at the very top of the kettle. If it's overflowing AND boiling then we will most likely have bubbly flow through the outlet. This could form slugs in the hose between them.
The variable temperature of the secondary outlet implies some kind of intermittent heat transfer, but varying on a timescale faster than the measurements were made.
Possibly :
a) Water level oscillating ... sometimes it overflows.
b) Slugs -- alternating water and steam in the hose between the eCat and heat exchanger
c) Percolation in the heat exchanger ... collecting water which is periodically percolated and expelled.
Note that this is a counter-flow heat exchanger, so we DO expect to see the secondary output track with the primary input.
Which mode has the highest heat transfer at the primary-input/secondary-output end?
Superheated steam .. good thermal conductivity, but low specific heat
Saturated steam ... poor conductivity, because it either has to condense or become supercooled.
Water ... high conductivity, high specific heat
