Power from the Mark I Panel

Howdy Ian,

Take a look at this very rough calculation.  It may contain errors and
gross omissions so beware!

-- DOS


First Order Power Estimate of Heated Flow
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Assumptions:
    1, Flow is at relatively constant pressure (ambient)
       and is therefore expanding linearly with Temperature.
       Obeying the ideal gas law: PV = nRT

    2, The entropy and enthalpy energy loss will be neglected.

    3, Input flow rate is constant 25 CFM at 21C and 101kpa
       ambient Temperature and pressure.


Source for Constants:

    http://www.engineeringtoolbox.com/air-properties-d_156.html


Method:

    1, Determine the mass flow rate at input.

        MassFlowRate = density * volumetric flow rate
        Density =     1.204 kg / m^3
        (for dry air slightly lower for wet air)

        MassFlowRate =
        1.204 kg/m^3 * 25ft^3/60sec * (12 (in/ft) / 39.37(in/m))^3

        MassFlowRate = 1.4206E-2 kg/s


    2, Determine the energy added to the flow per unit
       mass due to temperature rise.

       Specific heat of air at constant volume at 21 C ~= 1005 J/(kg*K)


    3, Determine the power added to the flow.

        Power = SpecHeat * TempRise * MassFLowRate
        Power ~= 1005 J/(kg*K) * 4.5 K * 1.4206E-2 kg/s
        Power ~= 64.2 J/s ~= 64.2 watts