The VAV DX systems in this New York high rise help reign in utility bills while maintaining optimum temperature control.

Flexible VAV systems prove the right fit for NYC space demands With the rising price of real estate in New York City, even older buildings have great income potential for commercial applications. That’s the feeling of Jack Resnick & Sons, the owner of 250 Hudson Street, an older commercial building located near the entrance of the Holland Tunnel.

Jack Resnick & Sons is a New York-based real estate investor with primary holdings in New York City. The company is a builder and manager of more than six million square feet of commercial space stretching the continent from New York City to San Francisco.

The Hudson street property is a 15-story high-rise constructed in 1931. Its address in mid-town Manhattan makes it an ideal location for corporate headquar-ters and general office space. But like many properties of its era, it was in need of cosmetic and mechanical upgrades to attract and maintain long-term ten-ants.

Vav as the way to go

As part of the $20 million capital improvement program, design engineers opted for VAV DX systems on each floor for ease of fit-out and better control of utility billing. With each floor measuring approximately 26,000 sq ft, an estimated 80 tons of cooling per level would be required to maintain optimum tem-perature control. United CoolAir Corporation was selected as the supplier of the VAV systems that were sold through MWSK Equipment Corp, United CoolAir’s rep agency in the New York City metropolitan area

“While many of the older buildings are quite large in their design, they were not constructed to accommodate new equipment change-out”, said Rod Beever, vice president of sales and marketing for United CoolAir Corporation. “This is an area where United CoolAir excels because we build our air conditioning equipment for just these kinds of difficult installations.”

Twenty-four 40-ton VariCool™ VAV units were specified, each with mechanically cleanable waterside economizers for reduced operating costs. They selected the VariCool™ units because the application required custom unit modification as well as a fast turnaround.

Customization and a quick lead time

MWSK Equipment Corp maintains offices in Manhattan and Long Island. They are no stranger to tough, retrofit projects, having developed quite a reputation for de-pendability in the city and surrounding areas.

“This project had many challenges on cost and turn-around,” said Bill Kerrane, president of MWSK Equipment. “But despite the customization required for each unit, United CoolAir was able to provide a lead-time of less than 10 weeks, seven weeks sooner than other manufacturers under consideration.”

United CoolAir Chief Engineer, Athar Khan, was heavily involved throughout the project from the very beginning. “It was a critical factor to work directly with the project’s consulting engineers and contractors to understand the project’s dynamics”, said Khan. “We were able to customize the units exactly as needed to eliminate time delays during installation.”

Getting 40 tons of cooling in an older property is a challenge at best, and this is further complicated when the mechanical spaces have barely enough room for the units themselves. The inherent flexible design of the VariCool™ meant they could be easily modified to adapt to the building’s space limitations saving on installation time and building modification. United CoolAir fabricated the units as a mirror image for left and right hand access, with sets of two units for each floor space. Victaulic couplings on the water lines made this portion of the installation quick and simple, providing additional benefits for the contractor and owner.Quiet op-eration was also key consideration because of the unit’s close proximity to the office space. Prior to the sale, MWSK acquired third-party verification that the United CoolAir units would be quieter than other VAV systems based on the same cfm and ESP capability. Each unit was equipped with a single power supply using a factory-installed, through-panel, non-fused disconnect. In the unlikely event of a VFD failure, the units also incorporated three-contactor bypass switches allowing manual operation of the blower. The controls package included factory-mounted, fully integrated Marvel Plus™ microprocessors that allowed each unit to be integrated with the BMS.The units arrived fully charged from the factory and in modular sections so they could be easily moved into the building. Quick-connect fittings eliminated field brazing by the contractor along with evacuation and charging of the refrigeration system. Time savings were estimated at several days of field labor for each unit, along with the added reliability of leak-free operation through factory-brazed joints.All aspects of the installation worked as planned, and the VariCool™ units lived up to their reputation for flexibility and ease of installation. But despite all the pre-planning, minor issues still cropped up once the units were installed, such as that of limited access door opening space. United CoolAir quickly designed “accordion” doors to open in the restricted mechanical rooms, and these were provided without delays to the commissioning date.