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Energy Efficiency in HVAC Systems with Philip Stephens

Director of Facilities Management Services, Carolinas Medical Center NorthEast, Concord, N.C.

Philip Stephens, Director of Facilities Management Services
Carolinas Medical Center NorthEast, Concord, N.C.

Your organization has gone through a major expansion in recent years. How has this expansion affected your priorities and decisions related to specifying HVAC products?

The expansions in the past three years at our hospital — 230,000 square feet — and the addition of a parking deck with 265,000 square feet have not affected the manner in which we specify the heating, ventilation and air conditioning (HVAC) equipment we use. But it has affected our priorities.

Prior to the last two expansions, the hospital had about 1,000 tons of standby cooling. Those expansions and the current surgery addition under construction will max out our cooling capability. Consequently, we are working with our architectural and engineering firm to increase the size of our energy center for future expansions and to maintain standby capacity.

How has the expansion affected your planning for testing, inspection and maintenance activities related to HVAC systems and components?

Due to our current cooling load and cooling capacity, we have placed increased emphasis on predictive maintenance and have added additional controls to our system to assist in identifying potential maintenance problems. Our planning has included the ability to connect a trailer-mounted chiller to our chiller-water loop if needed during summer peak loading.

What kinds of future expansion to your facilities are you planning for now?

We are currently constructing a 65,000-square-foot addition to our surgical department and are in the early planning stages for a new bed tower. Our current chiller load, coupled with plans for the future, has created the need to expand our energy center to include standby capacity.

To meet future needs for system reliability and energy efficiency, what types of new HVAC technology are you exploring?

We will remain with centrifugal chillers but are looking at more efficient models and distribution systems. We also are working with our controls provider to improve our building management system for improved efficiency and are looking at the possible replacement of several older, inefficient air handlers.

On the boiler side, we are planning to look at the advertised merits of an electrical boiler. Our current boiler capacity is more than adequate, but we will require additional capacity when the bed tower becomes a reality.

Beyond what you've mentioned previously, what are your biggest challenges in ensuring your facilities' HVAC systems operate energy efficiently?

Currently, the toughest challenge is the older equipment. About 50 percent of our air handlers and distribution systems are 40 years old or older. Those systems do not have the manufactured efficiencies of systems today and, due to wear and tear, have become less efficient than their original designs. Although we maintain our equipment to high standards, it is not always possible to achieve design flows and temperatures.

What steps have you taken or are you looking into to address these challenges?

We are looking at each air handler, each chiller, cooling towers, pump systems, boilers, condensate systems and distributions systems to develop a logical replacement or upgrade plan. We have increased our maintenance effectiveness through improved testing and increased predictive maintenance.

We also have improved the effectiveness of our steam-trap program and are tracing all steam and condensate lines to eliminate leaks and replace insulation where needed. And we are working closely with our controls provider and our architectural and engineering firm to upgrade current

posted:  2/15/2008