Energy Use Comparison for Series vs. Parallel Fan Powered Terminal Units in a Single Duct Variable Air Volume System

Previous papers under RP 1292 presented engineering models and experimental verification of those models for series and parallel VAV fan powered terminal units. This paper presents the results from the research in terms of power consumption for series vs. parallel fan powered terminal units (FPTU). Each system type was simulated in a base configuration for Houston, Texas and six different scenarios were simulated for comparison. The primary case was expanded to cover other geographic/weather locations which confirmed this trend. Previous results from RP-1292 showed that parallel FPTU have a leakage rate of up to 20% of primary air. When this leakage is included in the simulation the series FPTU fare much better. If 20% parallel leakage is assumed, the series system consumes 6% less energy than the parallel system.