“Be kind, for everyone you meet is fighting a hard battle” - Often attributed to Plato but likely from Ian McLaren (pseudonym of Reverend John Watson)

Wednesday, June 19, 2013

"Free" energy

Image Credit: Sweet Samoa
In my feeds from the soon to be late, lamented Google Reader (the company whose motto should change to "Evil R Us") I've included the aggregator "Alternative Energy News." Many of the articles are interesting and discuss important ideas and developments. Others... not so much. For example, articles from "Pure Energy Systems Network" (PESN)" are aggregated. This is a site that delves into the world of such exotica as gaining useful energy from  zero point energy, magnet motors, motors that are alleged to run on the energy in cavitation, energy from "low energy nuclear reactions (LENR - the new name for what used to be called 'cold fusion')," and others. The sense of the site is, unsurprisingly, that any or all of these could change the world but for the oppression of the powers that be (our government and corporate overseers).

The subject of this post is the "Molecular Impact Steam Technology (MIST)" engine. This technology claims to utilize hypersonic water jets to "explode hydrogen bonds" in water, thereby releasing enormous energy, thus producing dry steam without heat input. MIST claims a "10:1 overunity factor," meaning that the energy available in the steam is 10 times greater than the energy used by the pump utilized for the water jets.

The claim is that one pound of water, using 127 btu of input energy results in dry steam with an energy content of 1,100 btu. First, let's convert to SI units using Cloudy. Rephrasing, 134*10^5 joules converts 0.454 kilograms (or 25.2 moles) of water into steam with an energy content of 1.16*10^6 joules.

Now, typically energy is released upon the FORMATION of bonds, not on the breaking of bonds (nuclear fission of atoms larger than iron is, of course, an exception). Therefore, the "exploding of hydrogen bonds" does not pass the initial "sniff test." Enthalpy of formation of hydrogen bonds in water is subject to significant variation, but a reasonable number is about -23.3 kJ/mol. This means that the formation of hydrogen bonds RELEASES about 23.3 kJ (kilojoules) for each mole of water. These 23.3 kJ must be SUPPLIED to each mole to break these bonds. In other words, energy must be supplied to break the bonds, breaking them does not release energy.

On their web site, there are many pages with calculations and data and a couple of papers on tangentially related topics. I'll dissect one such page.

The claim is that the increase in specific kinetic energy (J/g or J/kg) in moving from a jet velocity of 810 m/s (where there was no dissociation from liquid water to steam when the jet impacted the chamber wall) to 3000 m/s (when steam was created) is from 320,000 J/kg to 4,500,000 J/kg. This is correct. But they claim this proportionality to v^2 as a kind of "mechanical advantage." Of course, the energy to accelerate the water must be supplied to the pump.

They then meander into a paragraph that mentions a 10 h.p. pump providing the pressure to process 120 pounds of water per hour. They state that 10 h.p. is 7.46 kW. So far, so good. They then divide by 60 and state that this is 124.3 watts per minute. Say what? Watts is already a "per unit time" unit. That is, the watt is a rate, not a quantity. Watts per minute is an acceleration of power, surely not what they mean. Heaven knows what they DO mean.

They then say that they pump 2 pounds of water per minute at 30,000 p.s.i. and 3,000 m/s. They next state that this is "1139 watts using only 124.3 watts of energy." Oh, brother! The watt is not an energy unit, it's a rate of supplying energy or doing work. The 124.3 came from  dividing the pump power of 7.46 kW by 60 for reasons unknown. So they believe that they're getting 1139 watts of output for 124.3 watts of input and that "the rest of the energy comes from the energy contained within the bonding of the molecules of water." Of course, breaking these bonds ABSORBS energy (specifically, around 20 kJ/mol or 1,120 kJ/kg).

It's hard to know whether they're aware that they're selling snake oil or just misguided. Perhaps they create steam more efficiently than a flame fire-tube or water-tube boiler (I'm no expert on the efficiency of boilers) but they certainly aren't achieving overunity by the freeing of hydrogen bond energy in water.

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