SENSITIVITY-BASED STABILITY EVALUATION OF CLOSED PIPING NETWORKS

Abstract

Aiming at a closed-loop water system of HVAC engineering, the authors put forward an evaluation method of systems’ stability based on sensitivity. It has three evaluating indexes: α – the summation of flow changes in other subcircuits influenced by resistance change in a certain subcircuit; β – the summation of flow changes in a certain subcircuit influenced by resistance changes in other subcircuits; γ – average β (or α) value of each subcircuit, reflecting the strength of regulating interference between subcircuits. The method is used to analyze the stability of a reverse return system (RRS) and a direct return system (DRS). The DRS subcircuit farthest from the heat source and the middle RRS are the least stable. Stability of the whole RRS is inferior to that of the DRS.