Premium
Superposition in Infiltration Modeling
Author(s) -
Sherman Max H.
Publication year - 1992
Publication title -
indoor air
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.387
H-Index - 99
eISSN - 1600-0668
pISSN - 0905-6947
DOI - 10.1111/j.1600-0668.1992.04-22.x
Subject(s) - superposition principle , infiltration (hvac) , airflow , stack (abstract data type) , stack effect , leakage (economics) , computer science , environmental science , mechanics , simulation , mathematics , engineering , meteorology , mechanical engineering , physics , mathematical analysis , economics , macroeconomics , programming language
Simplified, physical models for calculating infiltration and ventilation in a single zone usually calculate the airflows from the two natural driving forces (i.e., wind and stack effects) separately, and then use a superposition rule to combine them. Similarly, superposition rules may be used to ascertain the effects of mechanical systems on infiltration. In this report a general superposition rule will be derived for combining wind, stack, and mechanical ventilation systems together. The superposition rule will be derived using general principles of leakage dismbution and airflow and will not depend on the details of a particular infiltration model. In the process of generating this rule, a quantity called leakage distribution angle is developed to quantify the separation of areas of the building envelope which are subject to infiltration and exfiltration. The general superposition rule is compared to other proposed superposition rules including those based on measured data, and the general rule is shown to have strong explanatory power Results are generated for typical buildings. The concept of fan addition efficency is developed to determine the effectiveness of unbalanced (mechanical) ventilation systems at augmenting infiltration.