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I would like to add to Bob Horst's comments on the series configuration of the heater coils.

The electrical resistivity of most materials changes with temperature. If the temperature T does not
vary too much, a linear approximation is typically used:

rho(T) = rho0 * [1+alpha * (T - T0)]

By driving the coils in series, you guarantee that they have the same current but not the same voltage.  
Even if you check the voltage at rest, this doesn't mean that the voltage won't change upon heating.  If
you are using nichrome wire, for example, the temperature coefficient is 0.0004, which seems small until
you multiply it times a (I don't know what you experience) large temperature difference.  A 150 deg C
difference times 0.0004, for example, equals 0.06 which means that the resistance of the higher
temperature wire is
106% (using a linear approx) times that of the null wire.  This would mean that the heat generated
(Power is current squared times the resistance) by the active heater wire would be about 6% more than
the heat delivered to the null module.  If the difference were 300 degrees, the error would be about
12%.  

If the charged module becomes hotter than the null module due to LENR, this will raise the resistance
of the hotter wire.  By raising its resistance, you also increase the amount of power delivered to that
module compared to the null module and thereby increase the apparent COP of the device.  If you
drove each heater separately, you could control the external power delivered to each module to make
sure that they are receiving the identical outside heating stimulus.

The error is compounded by positive feedback.  In other words, if you are delivering an extra 12% to
the
active heater wire, then its temperature will rise more (let's say 6% more due to increased emissions =
cooling effects)
and therefore its resistance will rise by an additional amount (let's say 3%) causing a additional
increase in its temperature.   

I believe that I have seen videos in which experimenters are instructed to carefully make sure that the
resistance of each coil
(the active and null) are identical while cool.  This is not an adequate method of guaranteeing that each
module is provided with the same wattage of heat and every experiment that has been performed
using these instructions is inaccurate and has reported a COP which is too high.

Alan Smith instructs people to wire the coils in series and to wind one clockwise and the other CCW
because,
"no magic, just easier".  I am waiting for a Thomas Clarke to get ahold of these unscientific techniques
that favor
positive results that are not justified.

Conductivity table referenced:
http://hyperphysics.phy-astr.gsu.edu/hbase/tables/rstiv.html

Oops!  They are using Kanthal wire with a zero temperature coefficient.

But, I cannot find a spec sheet on such a wire.  The temperature cooefficient might be less, but it is still
positive.

Kanthal A is a ferritic iron-chromium-aluminium alloy (FeCrAl alloy) with high resistivity and good
oxidation resistance for use at temperatures up to 1350°C (2460°F).

Kanthal A is typically used in industrial furnaces and home appliances. Examples of applications are
elements embedded in ceramics for panel heaters, infrared heaters, warming plates, irons, ceramic
pots, in cartridge heaters for liquid heating, storage heaters, in ceramic heaters for cooking plates, air
guns, hobby kilns, radiators, in quartz tube heaters for space heating, toasters, toaster ovens, grills,
industrial infrared dryers, coils on molded ceramic fibre for cooking plates with ceramic hobs.

Temperature °C        100        200        300        400        500        600        700        800        900        
1000        1100        1200        1300
Temperature factor of resistivity
Ct        1.00        1.01        1.01        1.02        1.03        1.04        1.04        1.05        1.05        1.06        
1.06        1.06        1.06
Temperature °C        Thermal Expansion x 10-6/K
Coefficient of thermal expansion
20 - 250        11
20 - 500        12
20 - 750        14
20 - 1000        15
Temperature °C        50        600        800        1000        1200
Thermal conductivity
W m-1 K-1        11        20        22        26        27
Temperature °C        20        200        400        600        800        1000        1200
Specific heat capacity
kJ kg-1 K-1        0.46        0.56        0.63        0.75        0.71        0.72        0.74




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