On Sun, Jul 3, 2011 at 6:17 PM, Jed Rothwell <[email protected]> wrote: > Jeff Driscoll <[email protected]> wrote: > >> >> >> 2. Rossi's assertions of that steam quality can be measured with a >> >> Relative Humidity meter (it can't). >> > >> > Yes, it can. >> >> No it can't, I wrote a detailed email on Vortex as to why it can't, >> maybe I should repost it. > > Experts in those meters such as Galantini say you are wrong. The > manufacturer's brochure says you are wrong. I suppose they are right, and > you are wrong. In any case, as Storms pointed out, the steam cannot be so > wet as to materially affect the conclusions. > The capacitance changes as the partial vapor pressure of the water changes. But in saturated steam, the partial pressure of the vapor is constant at 14.7 psi for all steam qualities between 0 and 100%. This is the key thing. So the capacitance won't change as the steam quality changes.
Also, the capacitance probe would get clogged up with water droplets, which would block the vapor from reaching the plastic capacitance sensor. It takes an expensive, complex meter to measure steam quality. The meter can not measure steam quality no matter what type of method (including non-standard) they use. Here is what I wrote on the Relative Humidity probe last week: ========================= Here are details on how a relative humidity sensor works (as others have also mentioned). It uses an extremely thin plastic (one manufacturer uses a one micron thick polymer) between two metal plates which creates a capacitor. I assume there are holes in the face of the metal plates so that the water can migrate into and out of the plastic faster. This is because the water couldn't migrate through the bulk fast enough if it just went through the microns thick plastic exposed at the edge. The capacitance changes as the water is absorbed. The manufacturer correlates capacitance with humidity and temperature in air at 1 atmosphere (if they wanted to go to higher pressures then then would have to add a device to measure pressure and add that as a correlation - but few customers would really need the capability for higher pressures) here are details on the construction of Relative Humidity meters: http://www.stevenswater.com/catalog/stevensProduct.aspx?SKU='51122' http://sensing.honeywell.com/index.cfm/ci_id/140576/la_id/1/document/1/re_id/0 http://www.ddc-online.org/Input-Output-Tutorial/Humidity.html http://www.jifbrunei.com/files/083DHumidity.pdf The amount of water absorbed by the plastic depends on how many water molecules hit the plastic per unit time which is directly related to the partial pressure of the water vapor. The sum of the pressure due to the water vapor molecules plus the pressure due to the air molecules equals 14.7 psia. The plastic absorbs more water when the partial pressure of the water is 3 psi than if it is 1 psi, for example. So, for example the vapor pressure of water at 90 C is 10.1 psia and therefore the air has a partial pressure of 4.6 psia (because 14.7 - 10.1 = 4.6). The plastic probably does not even know the air is there - i.e. the capacitance may not change much if the air was taken away while keeping the water at 10.1 psia. At 100 C (boiling), the vapor pressure of water is 14.7 psia and the capacitance is some value. Here is the key point: At 100 C, how much water would the plastic absorb if the steam was 100% quality (i.e. dry) compared to 0% quality (i.e. wet or also known as fog). The answer is the capacitance would be virtually the *same*. The reason is because the partial pressure of the water vapor is the *same*. The amount of water molecules hitting the plastic stays the same as the steam quality increases from 0 to 100%. So therefore, a Relative Humidity meter can not be used in any way to determine the quality (also known as dryness) of the steam and the supposed expert Galantini made a huge mistake. here are some graphs of water vapor pressure for reference: http://en.wikipedia.org/wiki/File:Water_vapor_pressure_graph.jpg http://www.engineeringtoolbox.com/water-vapor-saturation-pressure-air-d_689.html Here are the specs on one of the probes Rossi used: HP474AC Relative Humidity Probe specifications: 5% to 98% RH >>> -40C to 150 C +/- 2.5% (5%...95%RH) +/-3.5%(95%...99%RH) Temp +/-0.3C Note that it works at 150 C. The probe probably senses a capacitance change as the temperature is increased from 100 C to 150 C but the water pressure would also have to increase so that more water was driven into the plastic of the capacitor. The capacitance changes as a function of water vapor pressure. It does not change as a function of steam quality. here is the Testo 650 relative humidity instrument that also Rossi used: http://www.ipi-online.com.au/test-and-measurement/data-loggers/testo/176-h2-data-logger Galantini wrote the following: "...The instrument used during the tests performed in the presence of Swedish teachers was as follows: 176 Text Code 0572 H2 1766 ." from the Testo data sheet: "...When normal humidity logers are too sensitive, the testo 176 H2 comes into its own. The robust metal housing resists mechanical influences and adverse ambient conditions. It has two connections for external humidity probes which can be positioned in the room according to the individual requirements." 4-channel temeprature and humidity data logger in metal housing with external sensor connections (NTC/ capacitive humidity sensor) * Large memory for 2 million measurement values - robust metal housng (without display) * up to 8 years battery life * Standard battery (AA) replaceable by user * Scope of delivery: Data logger testo 176 H2 incl. wallholder, lock, batteries, calibration certificate and instruction manual Measuring range -20 to +70°C -40 to +70°Ctd 0 to 100%RH Accuracy ± 0.2°C (-20 to +70°C) Resolution 0.1 °C 0.1 %RH / g/m³ Conclusion: Galantini, a chemistry professor (as far as I know) screwed up royally. Keep in mind, Rossi keeps insisting on measuring energy using water vapor that he quickly gets rid of down a drain. Is there a reason he gets rid of the evidence? Is there a reason that Galantini used the wrong sensor for steam quality? >> >> Rossi's claims >> > have been independently confirmed by Defkalion, so there is no doubt >> > they >> > are real. >> > >> > >> Greeks have their backs up against a wall financially speaking and >> desperate people will do desperate things. > > That's preposterous. The Greek government is in trouble. Most Greek people > are fine. Most of the investors in Defkalion are not Greek, and they have no > reason to do anything "desperate." The regulators are not going to cooperate > in a scam no matter how "desperate" they may be, because it cannot earn any > actual money. > If that is your best argument, you should hang it up. > - Jed >
