Retrofit Fan Coil Units Reduce Energy Consumption While Providing a Comfortable Indoor Temperature for Occupants

Construction plans at BMC aims to streamline operational efficiencies and reduce energy consumption.

Construction plans at BMC aims to streamline operational efficiencies and reduce energy consumption.

Boston Medical Center (BMC), a medical facility providing inpatient, outpatient and emergency care in the heart of the Boston’s historic south end, needed to address challenges associated with a merger which resulted in a split campus configuration. In addition to necessary updates to its facilities and overall HVAC equipment, a primary focus involved a multi-phase mechanical system retrofit initiative throughout the BMC campus.

Kicking off a four-year, clinical campus-wide redesign project, the project as a whole was slated to yield at least $25 million in annual cost savings upon completion, including several construction plans aimed to streamline operational efficiencies as well as reduce energy consumption.

“Our goal is to enhance our patient experience by consolidating our services, while ensuring we are operating at the highest possible efficiency,” says Mike Canning, senior director of facilities at BMC. “This meant addressing several facilities issues we inherited from the hospital merger, including those in which energy efficiency could be improved.”

The BMC project team approached consulting-specifying engineering firm Engineered Design Solutions regarding a solution to replace old steam radiators that were part of a larger boiler/chiller system, and with recommendations from Stebbins Duffy Inc., Engineered Design Solutions specified a network of fan coil units from International Environmental Corp. (IEC).

“Of primary importance was identifying a cost effective, low maintenance HVAC solution that could be installed in phases within occupied buildings,” says Jack Nelson, principal of Engineered Design Solutions. “BMC also wanted to make sure that the system would operate as quietly as possible, as well as be able to accommodate a low water pressure drop.”

A total of 84 IEC fan coils – including 68 Vertical Classic Series (FXC), 10 Horizontal Hideaway with Plenum Series (CPY) and six Vertical Class Hideaway Series (FHC) units – were specified for the initial phase of the mechanical system retrofit project. Slated for installation in exam, intake and inpatient rooms, the units would provide a total of 150,815 btus of heating and 102,593 btus of cooling capacity once integrated with the existing boiler/chiller system.

All units were specified with an electronically commutated motor (ECM) to regulate airflow with proportional control and thus minimize sound during operation. Additionally, special coil circuitry and coil fin arrangements were required to provide the necessary low water pressure drop at the required water flow rate for year-round heating and cooling.

“The integrated EC motors ensured that the units, which would be located in patient rooms and other areas requiring minimal operational sound, would function virtually undetected while providing a comfortable indoor temperature for occupants,” says Nelson.

Mechanical contracting firm EMCOR Group Inc. began installing the IEC units on the 7th, 8th and 9th floors of the Dowling Building in mid-May of 2014. This followed work earlier in the spring by general contractor Wise Construction to open pertinent walls and remove soffits and steam lines associated with the original HVAC system. After this was completed, EMCOR oversaw the coring of holes for the new piping system, and installed the hot and chilled water mains. The complete seven-phase construction process, which occurred simultaneously on all three floors to allow for convenient access to the HVAC system from all angles, included an average of 15 IEC fan coil units per phase.

A total of 84 fan coil units are specified for the initial phase of the mechanical system retrofit project.

A total of 84 fan coil units are specified for the initial phase of the mechanical system retrofit project.


“We were working with an aggressive project timeline, including at one point needing to accommodate the Memorial Day weekend, around which time it was planned to install a large number of the units,” explains Ed Tremblay, head technician and project manager at EMCOR. “This meant that every aspect of the HVAC installation needed to run smoothly.”

EMCOR Group coordinated with Stebbins Duffy to warehouse the complete shipment of IEC units, which were designed with extensions on both sides of the fan coil cabinet to accommodate piping and controls. Both the design and the warehousing enabled EMCOR to pre-fabricate the piping of the coils, as well as install the control and isolation valves, ahead of time.

“We had three guys working on the pre-fab on an ongoing basis for about a month, which helped keep us on schedule,” Tremblay says. “This made it possible for us to just drop in and install the fan coil units as we needed them.”

According to Stacie Suh, engineering account executive at Stebbins Duffy, IEC’s ability to provide a flexibly designed solution equated to the BMC project’s success.

“With this kind of flexibility, we were confident to recommend the IEC units, which fit the specific requirements of the project,” Suh says.

The complete mechanical system retrofit project, which remained ongoing throughout the renovation at-large, was completed in August of 2014. Since that time, BMC experienced more comfortable heating during the winter, and expects similar functionality in the fan coil units’ cooling mode throughout the first official summer in operation.

“There was a noticeable difference in more even heat compared to the old steam system over the winter,” says Tremblay. “We are pleased with the success of this project – from unit design and delivery, through installation and operation – and anticipate future opportunities with BMC as a result,” says Suh.

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