The University of the South: Jessie Ball duPont Library

Solution Overview

Comprehensive HVAC equipment, sensors, and controls upgrades lead to improved performance, reduced costs, and better humidity control for books and sensitive materials.

Background

The Jessie Ball duPont Library was completed in 1965 and serves as the sole library for the University of the South. In addition to the traditional book stacks, the library offers office space, meeting rooms, computer labs, and a 24/7 learning commons to a student body of 1,800, as well as the wider local community.

Typical for the time of construction, the original HVAC system included a dual-duct constant air volume (CAV) system for airflow, with 160 tons of water-cooled direct expansion conditioning for cooling and a gas-powered steam boiler (66 percent efficient) for heating. The dehumidification was never fully realized and the constant air flow resulted in high fan use for the designed ventilation standards. This system had been connected to direct digital controls (DDC) since 1992.

Solutions

The University designed and constructed a 680.7 kW/ton central chilled water plant in 2000 (and added an additional 500.3 kW/ton in 2013) and has been expanding the building system loop systematically to include existing structures and new construction. Mechanical and technical upgrades, along with utilization of the central chilled water plant, have resulted in significant energy savings at the library.

Savings Measure

Costs

Notes

Interior piping to tie into campus chilled water loop$161,000Exterior piping for expansion of chilled water loop was completed under another project. Allowed for removal of old, packaged HVAC units.
Air Handling Unit replacement$297,000Trane Modular Climate Changer units (3) with variable frequency drives.
Trane CSAA size 66 – 34,000 CFM
Trane CSAA size 35 – 17,000 CFM
Trane CSAA size 21 – 11,000 CFM.
Boiler replacement$166,000Two condensing boilers installed, sized at 1750 MBH each and with an estimated thermal efficiency of approximately 98%.
Variable air volume (VAV) boxes to replace CAV$93,000Low profile Trane VAV boxes installed with hot water reheat coils. New 2-way modulating controls were installed at each heating coil. All heating coils are in the reheat position.
DDC and building automation system communication upgrades$162,000Carbon dioxide (CO2) now monitored at the zone level for demand controlled ventilation strategy.
kWh monitoring$6,100Setra Power Patrol building meter installed for real time electrical monitoring.


With the library retrofit project completed, the plant now serves 500,000 square feet – nearly one-third of the total campus square footage. The renovation was completed without disruption of library services.

Other Benefits

Improved occupant comfort has been realized with more consistent thermal comfort in all four library levels. True dehumidification is being achieved with reheat coils, creating better conditions for preservation of books and sensitive materials. The installation of CO2 sensors in the VAV zones has resulted in decreased fan runtime and long-term maintenance savings.

While the central chilled water plant has not yet reached total capacity, additional load is expected and a satellite plant will be needed in the future. The design for this future plant was incorporated in the pipe sizing, electrical panels, and mechanical room’s physical space during this renovation.

Image Gallery

Student sitting at table

Study area

Overhead piping services

Overhead piping services

Removal of air handler

Removal of air handler