Geo, Unless PeterP's nano particles are micro bots with sharp...

Geo,

Unless PeterP's nano particles are micro bots with sharp little sticks and an attitude problem.

(Is joke)

The key to heat transfer is (I suspect and as others have stated) the area of the fracture zone and (therefore) the fluid flow rate at peak temperature in the primary 'circuit'.

There may be a role for more thermally efficient fluids in the secondary loop except for issues around turbine wear. Even tiny amounts of impurity in the demineralised water of the secondary loop can create havoc in the turbine HP blades.

Not sure how the condenser circuit will operate (tertiary loop) and a more efficent fliud << may >> help esp if GDY are using dry cooling. Milmerran for example uses dry cooling and has condenser vaccuum problems (off-loading) in summer due to lack of cooling efficiency.

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