Horace, This is very provocative. Perhaps a simple static (pressure differential) experiment could be 'telling' without going all the way to dynamic circuit... IOW is "flow through" really necessary, given that Raney nickel could provide the necessary cavities, in a static colloid, so that normal convection would suffice?
Another option that comes to mind is that the boiling point at ~170 F is only a few degree from that of ethanol. Some kind of fugacity experiment is possible, but I haven't got a handle on it yet. The vapor pressure could be amplified by a mix of the two. .... wish Sparber could participate, as this is the kind of thing Fred really enjoyed. He would be sure to bring up his patent for keeping a cow trough ice-free. BTW - if your concept worked, and a Casimir cavity boiler could produce a usable Carnot spread between a hot and cold side of a constantly vaporizing liquid, near its boiling point; even if the differential was small, then an implementation might be a modified Stirling. It might require using very large pistons or drumhead resonator - to squeeze much power out. The efficiency would be very low but who cares? if the energy is free and the thing can be constructed of cheap structural materials like polyethylene and fiberglass? Anyway, let me say up front, having worked with carbon tetrachloride in the past in the plastics industry (no 'Graduate' jokes please) that it is nasty stuff, made more problematic by what some consider to be a pleasant ether-like aroma. It is a solvent for many plastics and can serves as a cheap and clear 'invisible glue' for acrylic. That it has substantial volatility at all is somewhat of an amazement in itself - due to the very high molecular mass of ~154 g/mol. It looks like the vapor pressure is ~12 kPa at around room temp, and would be similar to ethanol at lower temps (I think) but should vary more substantially around the boiling point. Things could be interesting in terms of a hot-cold dichotomy with the Casimir supplying whatever heat is removed, in the form of kinetic energy, from an insulated Stirling system. Anyway, in side by side experiments, at the same temperature, in which the CCL4 was used with or without a little Raney nickel, as a colloid, I am wondering - would there be a meaningful pressure differential from the nickel addition alone? To make it more apples-to-apples one could add the same weight of powdered micron-sized nickel to the other side. Would that pressure differential be amplified if there was equal amounts of ethanol in the mix and both samples were on the same hot plate at about 168 F ? There are probably better ways to approach this, perhaps they will become clearer after a caffeine infusion <g> -----Original Message----- From: Horace Heffner PROPOSED EXPERIMENT An experiment to evaluate CCl4 prospects for a Casimir force boiler would consist of measuring any boiling point depression from imposing a fine mesh barrier between the liquid and gas phases of CCl4. A closed circuit with condenser would be used to recycle the CCl4. A controlled heater and stirrer would be used to maintain the temperature of the liquid phase. The interesting part is deciding what to use for barriers, i.e. flow- through Casimir cavities. One possibility is sintered fine metal powders. Another is stacked fine foils, like gold leaf, with a dielectric powder or micro-beads used as a plate separator. Plate separation has to be under 10-7 m to obtain any effect.
