Patent ID: 9696057
Date: 2017-07-04
CPC Classifications: F24F,G01M

Claim:
1. A method for measuring HVAC efficiency for use with an HVAC system which includes at least one fan for moving air through the system, at least one heat transfer element which acts to effect heat transfer to or from the air within the system, wherein the direction which the fan forces the air through a duct within the HVAC system is considered downstream, the method comprising the steps of: (a) turning off all heat transfer elements; (b) after step (a), running the fan until the system reaches a steady state condition; (c) after step (b), measuring the enthalpy of the air within the HVAC system at a predetermined point in the duct downstream from all heat transfer elements; (d) after step (c), turning on a selected heat transfer element to be measured; (e) after step (d), running the HVAC system until it reaches steady state; (f) after step (e), measuring the heat transfer rate introduced to the HVAC system by the selected heat transfer element; (g) after step (f), measuring the enthalpy of the air within the HVAC system at the predetermined point; (h) using the measured heat transfer rate caused by the selected heat transfer element and the change in enthalpy of the system air to calculate the air flow within the HVAC system; (i) after step (h), adding a passive element to the system or modifying a preexisting passive element in the system, the passive element not acting to significantly effect heat transfer to or from the air within the system; (j) after step (i), running the HVAC system until it reaches a steady state; (k) after step (j), measuring the enthalpy of the air within the HVAC system at the predetermined point; (l) after step (i), measuring the heat transfer rate of the selected heat transfer element; (m) after step (l), determining the change in the heat transfer rate introduced to the HVAC system by the introduction or modification of the passive element performed by step (i); (n) after step (m), using the change in heat transfer rate and the change in enthalpy to calculate the air flow within the HVAC system; and (o) using the change in the heat transfer rate and the change in air flow between those values for the HVAC system obtained prior to step (i) and those values for the HVAC system obtained at steps (m) and (n) to determine the efficacy of the addition or modification of the passive element.