Abstract: A heat exchanger tube includes a first pass for at least partially combusting a fuel and the first pass having a modified shape including a minor diameter and major diameter that reduces the external pressure drop of an external fluid flowing across the heat exchanger tube. A HVACR system includes a heat exchanger tube with a first heat exchange pass that at least partially combusts a fuel and has a modified shape.

Abstract: Disclosed herein are systems and methods for predicting an energy savings resulting from the replacement of existing equipment with new equipment. In the example embodiments, the energy saving prediction is utilized to create a customized warranty for an individual customer of an HVAC system or subcomponent thereof. Historical energy usage, historical climate data, old and new equipment parameters, and customer use data is input to a predictive modeling algorithm, which determines an energy savings prediction. Alternative models may be employed and a weighting factor applied to each to arrive at an improved energy savings prediction. The energy savings prediction is utilized to warranty to the customer an estimated dollar savings that will result from the installation of the new equipment. The warranty provides that, in the event the predicted energy savings is not realized, the customer is entitled to receive a dollar amount representing the shortfall in warranted energy savings.

Abstract: A heating, ventilation, and/or air conditioning (HVAC) system has a motor configured to selectively provide an airflow, an airflow control algorithm configured receive an input and to provide a desired control value associated with a desired actual operation value of the motor, wherein the desired actual operation value is provided as a function of the input, and a control translator configured to receive the desired control value and to provide a correlated control value to the motor, wherein the correlated control value is associated with causing the motor to operate at the desired control value.