Project Snapshot: Wellesley College | Field Erected Air Handling Unit

Project Name: Whitin Observatory Renovation
Owner: Wellesley College
Architect: designLAB architects
Mechanical Engineer: Fitzemeyer & Tocci
General Contractor: Shawmut Design & Construction
Mechanical Contractor: E.M. Duggan
Equipment: Indoor ERU in 4 sections
Manufacturer: Annexair
Size: 2,400 CFM OA
DAC Sales Engineer: David Goodman


Project Highlights:

Whiten Observatory-1History: The Whitin Observatory is the home of the Wellesley College Astronomy Department and houses classrooms, astronomy laboratory facilities, the Astronomy Library, and faculty offices.  Built in 1900, and enlarged in 1906 and 1966, it was ready for expansion and renovation scheduled for 2009-10.

HVAC Highlights:  Piping was routed underground from the Science center so Hot Water/Chilled Water could be used for heating and cooling.  To meet ventilation code and save energy an enthalpy wheel type ERU was installed to condition all spaces.  The new unit included filters, Enthalpy Wheel, dual function Hot Water/Chilled Water coil, Direct Drive fans and an electric heater for reheat or backup. Whiten Observatory-2

Rigging Challenge:  Although the design supply (2,200 CFM) and exhaust (1,900 CFM ) was relatively low, the unit was still 13 ft. Long and 5 ft wide.   The unit was to be located in the corner of the basement where it would be closed in after install.   Access to the basement corner was through an opening in the floor and enlarged brick hole.  The unit was designed in 4 sections with 3 splits to be field joined by the EM Duggan crew.

Whiten Observatory-5Unit Controls:   The unit was designed with VAV capabilities and programmed for schedules and CO2 sensing.   The unit came equipped with damper actuators, freeze protection override on the wheel and VFDs with I/O points factory wired to a terminal strip.  The Direct Drive fans and Enthalpy Wheel were also factory wired and designed for quick connect in the field.  All other controls were provided by the ATC contractor.  The electrical and ATC contractors reconnected the loose power wire ends to the 3 motors and added their sensors and flow stations where needed.  They also conveniently located and mounted a unit control panel.  The panel provided run and speed signals to VFDs,  Enthalpy Wheel control, damper signals, and Hot Water/Chilled Water valve position.

Whiten Observatory-4 Whiten Observatory-3

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