After a study of Pennsylvania State University - Brandywine Campus’ (PSU-BC) Vairo Library, we provided a report of HVAC system improvements that included construction costs, energy impacts, annual operating costs, and net present value. The primary objective of the improvements were to increase the ability of the system to eliminate existing humidity control issues and control temperature in an automated, cost-effective manner. Our study report included six primary options, four of which had lighting sub-options, totaling 10 combinations. After selecting one option presented in our report, the University then requested that we provide the design for the defined improvements.
Having considered the effects of full HVAC system replacement, as well as lighting upgrades, the final design encompassed HVAC system renovations, including new variable frequency drives (VFD) to reduce airflow when building HVAC loads are less than peak. Manually adjusted pneumatic control components were removed and new direct digital controls (DDC) were provided for each air handling unit that would be tied into the campus-wide DDC system. The new system provides unit level controllers with capability for future expansion to handle zone level DDC, including the ability to operate with optimization routines, such as supply air static pressure reset, supply air temperature reset, and morning warm-up/cool-down. Modifications were also made to existing pneumatically-controlled VAV boxes and reheat components.
After implementation, PSU-BC will reduce their annual operating costs for the Vairo Library by 35% or $64,500. The simple payback period for the project is 2.8 years.