Kirchhoff's loop rule (otherwise known as Kirchhoff's voltage law (KVL), Kirchhoff's mesh rule, Kirchhoff's second law, or Kirchhoff's second rule) is a rule pertaining to circuits, and is based on the principle of conservation of energy.
ECM stands for Electronically Commutated Motor. Basically, circulator pumps with ECM motors offer intelligent speed control. Speed-controlled pumps automatically adjust their output to changing demand, whether it be due to outside temperature, level of sunlight, overall activity, and other heating sources. The benefit of having a more efficient ECM motor pump is substantial energy savings, which directly relates to cost savings.
Quick Answer. A car's electronic control module is the computer responsible for providing fuel to the engine and controlling the quality of the car's emissions. The ECM uses a microprocessor and software to analyze and respond to the input values from an array of sensors. An ECM is typically part of a larger system, with multiple modules that control everything from power steering to airbags, commonly called the car's computer.