Proposal of a new method for the characterization and operational air leakages assessment in HVAC systems

Reducing air leakages in HVAC systems is potentially one of the actions with the best potential for energy savings in the residential sector. The assessing of air leakages in HVAC systems is currently addressed in two ways: i) the traditional DALT (Ducts Air Leakage Tests) to characterize and compare ductwork and ii) the ASHRAE 215:2018 standard method to measure leakage at nominal working conditions. In this paper an innovative experimental method for assessing air leakages in HVAC systems at operative conditions is proposed. The method is based on flow rate measurements at different pressures and performed with closed terminal dampers. The so called “Shut-Off Method” has been then experimentally validated in a real plant showing good agreement with the ASHRAE 215 procedure. Finally, on the basis of the Shut-Off model application, the leakage coefficient used by the standard DALT classification procedure was calculated, showing leakage performance 2,3 times worse than the Eurovent Class A requirements.