i was thinking about 180° of you solution, but because gravity force and fluids in the pipes ...
In you solution at the moment there liquid in heatpipes changing they aggregate state to gas on contact surfaces, what are on the top. You bacame a bubbles, and new luquid has problem to became a contact direct to hottest surfaces.
My solution where better, so the steam bubbles will go up like in a pan with water on the kitchen stove

something like this from Genesis mining farm in Island