Workers at the Delaware Memorial Bridge Toll Booth Plaza in New Castle, Delaware, reported uncomfortable conditions in the toll booths, especially in the winter months. The Delaware River and Bay Authority (DRBA), operator of the Plaza, elected to have a study performed to evaluate the existing HVAC systems, ultimately resulting in a complete overhaul of the existing distribution system.
The study reviewed the performance of the existing HVAC systems, surveyed neighboring toll authorities to gather input regarding their best practices, reviewed scholarly materials, and provided recommendations in order to correct performance issues and improve thermal comfort. As part of this effort, Kleinfelder took measurements to obtain quantifiable performance data and surveyed DRBA staff. During the analysis, an HVAC balancing contractor was engaged in order to provide airflow and hydronic flow readings at various points in the existing HVAC system. This study concluded that there was a lack of proper airflow to the booths, and deficiencies were identified in the overall system control strategy and how air was being introduced into the booths.
The existing variable air volume (VAV) air handling unit was replaced with a new VAV unit. New constant volume boxes with heating water coils were provided for each of the individual toll booths. The branch pipe size serving each of the constant volume box reheat coils was increased one pipe size, which improved the overall flow to each of the reheat coils.
In addition, a higher volume of airflow was provided to each booth than had previously been delivered. The improved airflow not only helped ensure a constant positive pressure within the toll booth, but also improved the health of the occupants by limiting the amount of vehicle exhaust that could be drawn into the occupied areas.
The replacement system was designed to be modular and able to be field-assembled and transported through an existing elevator. This unit also included two parallel supply fans that allow the system to operate even if one of the fans is down for service or maintenance. Lastly, supplemental toe kick heaters that operate on automatic timers were installed under each of the booth stations where the operators are seated.
The design approach proved to be successful in keeping the booth operators comfortable. DRBA staff remarked that for the first winter that they can remember, no complaints about temperature conditions in the toll booths were received. Through a proactive and informed approach, DRBA and Kleinfelder were able to provide a modern, comfortable environment.
Location:
New Castle, DE
Owner:
Delaware River and Bay Authority
