I was bored, so I am striking from orbit.
Nonconductive liquids for PCs and data centers, molten salt reactors, etc.
Water (pure) is non-conductive, that is why its used as an insulator and dielectric in ultra-high voltage machines.
Actually, it has a very high specific heat, 2nd best after ammonia, the latter presenting its own nasty problems.
Depends what you mean, and how its measured, and at what temperature, at room temperature, liquid water is 3rd best, after gaseous Hydrogen(3+x better) , Helium (20% better). Gaseous ammonia is 1/2 that of water, and about the same as methane.
Liquid helium obliterates EVERYTHING in terms of specific heat. Liquid hydrogen is pretty good as well, on a per mass basis.
Water actually isn't so bad for heat transport as long as a phase change is involved.
Given its relatively wide liquid range, that at the lower end covers normal heat rejection temperatures, its actually a near ideal fluid for heat transfer (also, low viscosity, relatively high density, and high thermal conductivity help), regardless of phase change.
Well, I'm sure if we had oceans full of mercury, we'd use it more often.
Actually NaK is far superior to mercury if going the liquid metal route. Mercury's low specific heat makes for HUGE up power requirements. Also, its high vapor pressure causes issues in design, which is why if going the liquid metal route, others are typically chosen.
1) 1000 deg F of heat is apparently bled into the atmosphere? I would think you would want to try and capture some of that with double-walled towers or something. I wasn't even aware that much heat was generated. I guess this place uses some technology I'm not familiar with.
You can't really do anything about it, its a matter of absorptivity (of solar spectrum light) vs emissivity (of blackbody radiation at the temperature of the absorber.
In fact, this ratio defines the -maximum- efficiency of a solar-thermal solution.
Sunlight corresponds to a blackbody in the 5300K range, so ideally you want something that has absorptivity of 100% at those dominant wavelengths (I.e., black), BUT absorptivity EQUALS emissivity at a given wavelength, so you then want something that has low absorptivity at longer wavelengths (e.g. 1.5-3+ microns for a 1000C collector), but, without resorting to photonic crystals (way too expensive for this large scale application), you are pretty much stuck with graphitic, ceramic, or refractory metals (coated with absorbing ceramics), as such, you pretty much get a flat emissivity curve. Thus, at most, ~85-90% of the incoming sunlight (regardless of concentration) gets turned into heat in the absorber, and the higher the temperature, the MORE you lose there...so its competing efficiencies (absorption efficiency vs heat engine efficiency).
Note, photovoltaic cells suffer from similar effects. A given semiconductor only will generate a photo-electron for wavelengths -shorter- than it is tuned for, and then only one per photon. So for a continuous spectrum (sunlight) you need a stack of cells to make maximum use of the incoming light.
The shortest wavelengths are absorbed first, then progressively longer as you go "into" the stack, with cell voltage roughly inversely proportional to wavelength.
