There seem to have been "homemade" serpentines for cooling (upstairs), another filled with Pt sponge, (or maybe later diamond and graphite), this/these large commercial condensers (image). Only the upstairs one seems to have been vented directly to the outside (if it existed at all).
Para,
I re-read some of the testimony, and just do not see where you came up with that? Nothing available to us as evidence so far shows anything upstairs, other than 3 windows, and empty space that Rossisays he is now converting to an office. All Penon's Final Report (207-58) says about the plant configuration is that water was pumped into the Ecat units, "heated to vaporization", "conveyed in a unique pipe" "outside of the shelter"...1MW plant I assume?, then "passed through the customer installation, where it cools to it's condensation".
Also, looking at his (Penon's) plant configuration diagram in the same document (207-58), it shows nothing about an ancillary heat exchanger system extending into the Leonardo area, along a wall, upstairs, and then back again (closed loop). At the least, he should have a brief annotated line marked "heat exchanger", and then have another schematic of it separately.
About Bass's "serpentine pipes", could you read the James Bass deposition (207-48), pages 135-136, and tell me what you think?