Comparing Guideline 36 Single Duct VAV Terminal Reheat Strategy with a Similar, Homegrown Approach (LB-17-C056)

ASHRAE Guideline 36 aims to standardize a set of best practices for HVAC control. This paper compares a single-duct VAV terminal reheat strategy developed and implemented at Appalachian State University with the dual maximum strategy included in Guideline 36. The two strategies are similar but they differ in the details of implementation. The Appalachian State strategy controls the reheat valve with the zone temperature. Discharge air temperatures are monitored and when that temperature reaches 90 F, the VAV damper modulates to cap the discharge air temperature at the 90 F setpoint. Using numerical analysis and actual performance data, this study looks at the implications of this variation and compare operational outcomes with those established for the dual maximum strategy outlined in Guideline 36 and other energy conservation standards.