Project Brief

Laurel Residence Hall is one of the student residences on NJIT's Newark campus. Under the PSE&G Direct Install energy efficiency program, KeRi was engaged by the program contractor, C-K Control Temp, to design the replacement of the building's central cooling and heating plant, and carried the work through signed and sealed permit drawings, submittal review and responses to requests for information.

On the cooling side, the existing chillers were removed and replaced with three packaged air-cooled scroll chillers, two at 80 tons and one at 111.6 tons, about 272 tons in all, producing 44°F chilled water. The new units sit on the existing steel dunnage on spring vibration isolators and reuse the existing electrical circuits, with new chilled water piping and isolation valves at each machine. Each chiller turns down to 10 percent of full load and is rated for low ambient operation, and a new local DDC controller sequences the plant and ties it into the campus building management system over BACnet.

On the heating side, KeRi designed the boiler room replacement around two condensing hot water boilers of 2,000 MBH input each, with dedicated boiler circulators, flue and condensate drainage details, and combustion air brought in from outdoors to NFPA 54.

MEP Engineering Scope

What We Engineered

Mechanical and electrical design for the plant replacement:

• Demolition of the existing chillers, keeping the existing steel dunnage in place
• Three new air-cooled scroll chillers, 80, 80 and 111.6 tons, on spring vibration isolators
• New chilled water piping and isolation valves at each chiller, with drain, refill and chemical treatment
• Existing chiller circuits reused, field verified for the new electrical loads
• Local DDC chiller plant controller with lead and lag sequencing, integrated into the campus BMS over BACnet
• Two new condensing hot water boilers, 2,000 MBH input each, with dedicated circulators
• Boiler room demolition and new work, with flue, condensate drainage and combustion air
• Signed and sealed permit drawings, submittal review and RFI responses

The Challenge

The plant had to be replaced in a building students live in. The new chillers had to fit on the existing steel and the existing power, and every shutdown of chilled or hot water had to be planned around the residents.

Our Solution

KeRi sized the new chillers to the existing dunnage and circuits, isolated them on springs, and added isolation valves so each machine can be serviced without draining the plant. Shutdowns carry 48 hours' notice, the loop is refilled with chemical treatment, and a new controller runs the plant and reports to the campus BMS.