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Friday, November 19, 2010

protocols applied to heat profiling on our tests

10

Dear Reader,

I'm simply trying to bend my mind around the logic required for the control on these tests that we're conducting.  We're attempting to establish the heat profile of that standard type resistor.  I'm writing this down because it sometimes happens that I then better understand the logic.  Here's the set up. 

We've contained the element inside water inside some hefty insulation that the heat is more or less trapped.  Now.  Our advice or instruction is to apply a series of graduated voltages to that rig - from small voltages of say, 10 volts to 12 volts - 16 volts - 24 volts and upwards - in a series of independent tests.

Then we record temperature rise, say every 10 minutes on each of those control tests.  That way we establish the graph - a time line against the record of temperature rise over a time - which can then be plotted on an  'x' and 'y' axis, I think it's termed.  And we allow each control test to run until the temperature has reached a predetermined maximum say of 60 degrees centigrade.

Then we apply standard protocols to those controls.  The value of the wattage is determined by the measure of the applied voltage divided by the Ohmage of the resistor to determine the rate of amperage.  Then, the applied volts multiplied by the applied rate of amperage flow - volts times amps or 'vi'  - determines that wattage empirically.  And then that wattage times the time taken to reach the pre determined temperature is summed to equate to the actual number of joules required to heat that body of water from ambient room temperature to that 60 degrees, say.  That rate of temperature rise will then precisely relate to the amount of energy dissipated to heat the water to that level expressed as power and related to the caloric values of the test.

In effect, if it takes 2 watts 12 hours to heat it to 60 degrees, and if it takes 4 watts 6 hours to heat it to 60 degrees, then it should take 3 watts 9 hours to heat it to that same level.  In effect we have a graphic indication of what energy is applied and dissipated which then, in turn, relates to the applied wattage delivered against that temperature graph.  Not only will we be able to determine the caloric values of those measured tests - but with those graphs we will be able to determine any arbitrary or 'in between' value by reference to those results that are then empirically evident.

This test is perfect.  In effect - when we apply this to a measure of our supplied energy from the battery supply source then it will relate to the rate of delivery determined by the amperage measured across the shunt multiplied by the voltage of the battery or volts times amps or 'vi'.  This wattage times the time it takes to heat that water to the equivalent 60 degrees will then be compared to the standard control test and any increase in the rate at which it heats that water from that applied wattage - will be a gain of our experiment over the control.  I see it now.

But there's a caveat.  We also need to gauge those smaller wattage values that will never be sufficient to heat that water to any discernible or measurable value.  Here the proposal is to take the readings of voltages applied from 2 volts upwards with the probe somehow positioned that it touches the actual body of the resistor and without immersing the resistor in water.  Here the object will be to apply a series of lower voltages to whatever temperature it stabilises at - against ambient room temperature.  The same protocols then apply - but this will determine the wattage but only with reference to ambient room temperature.  Because of the small heat values associated with this lower wattage - it will be the only reasonable means of determining those wattage values that we anticipate on the experiment itself.

Personally - I see no difference between the two tests other than the fact that the one dissipates its energy into water - which becomes the standard reference and the other that dissipates its energy into the surrounding atmosphere.  But the former test has the advantage of a reference to it's actual intended application.  And in as much as the dispersion of that heat is more general - less localised - it is probably a fairer indication of the total heat dissipated.  This the more so as it is understood that the on our earlier tests the resistor has localised areas of heat that can vary. 

Regards,
Rosemary

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