Oversizing Analysis of HVAC System in Prototypical Commercial Buildings

Abstract

Oversizing of heating ventilation and air-conditioning equipment becomes an intractable fault once the building system is designed and constructed. It imposes control challenges, impacts the indoor air condition, increases energy consumption, and reduces the equipment life span. As a system-level fault, it is difficult to duplicate and quantify in an experimental environment. This study analyzes the oversizing issues in prototypical commercial buildings. Data of system operations from 12 retail stores in different climatic regions in the US are collected. We applied three parameters, including cycling number, run-time fraction, and maximum cycling number, to capture the oversizing signature of a RTU based on the annual design conditions. Two different effective dead-band temperatures are adopted to evaluate the potential uncertainty. The findings can be used to assess the oversizing level of RTUs, quantify the average energy penalty of sample buildings, and guide future design. More importantly, the methodology can be automated and applied in smart building management systems for soft-repairing of an oversizing issue.