a) The pump does add a tiny amount of heat to the water passing
through it : the input temperature should be measured AFTER the pump.
b) There is FRICTIONAL loss in a pipe
http://www.efunda.com/formulae/fluids/calc_pipe_friction.cfm
(Though in that calculation it's expressed as pressure drop).
These aren't going to be anywhere near the measured power level.
Hey! Another fake-let !!!
c) The water could drive an internal turbine, generating heat
directly (friction) or indirectly (generator connected to a resistor).
