With large central utility plants, over-taxed HVAC systems and ever-increasing utility costs, many hospitals face the dual problems of high energy costs and compromised environmental air quality. By taking a "total systems approach" to energy management, hospital engineers at Methodist Dallas Medical Center (MDMC) were able to solve these problems with a new turnkey central utility plant that significantly reduced energy costs and restored air quality. Central to the plan's success are a new Daikin 2,000- ton dual-compressor centrifugal chiller, variable frequency drives and new controls that gave the hospital an 18-month return on the investment while saving seven percent in utility costs.

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Founded in 1927, the 500-bed Methodist Dallas Medical Center serves more than 160,000 patients a year and has received a Gold Seal of Approval^® from the Joint Commission on Accreditation of Healthcare Organizations. An expansion project that will add a 100,000-square-foot medical office building and update existing outpatient facilities will bring the total space to more than one million square feet.

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Hospital sought solution for "hot spots"

The previous HVAC system serving the facility included one 1,400-ton, one 1,100-ton and one 650-ton centrifugal chiller. Although just 15 years old, the existing HVAC system was unable to handle the increased cooling load at the expanding hospital.

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Hospital staff complained about "hot spots," especially in areas farthest from the central utility plant. In addition, the hospital was facing significant increases in energy costs due to increased gas costs as well as increased transmission and distribution costs.

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"We had run out of chiller capacity," said Charlie Shoup, assistant administrator for engineering and safety, Methodist Dallas Medical Center. "The chillers were running at 100 percent 24/7 for three months in the summer. "We got to the point where the central utility plant was not able to produce the required 42°F chilled water. During hot summer months, we could only produce 50°F chilled water." Both the chilled water and condenser water flows were out of acceptable range due to improper pump calibrations. As a result, the air handling units could not produce the leaving air temperatures needed to control humidity. This affected environmental comfort throughout the hospital.

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Although the immediate "culprits" appeared to be the mismatched chillers and pumps, fixing them would have solved only part of the problem. "We wanted a best-case scenario and a long-term solution," said Shoup.

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Total solutions approach helped achieve goal

Shoup and his staff had been working with Ron Green, president and founder of Energy Integrators, Inc., Dallas, an independent energy consulting firm, to develop a long-term utility management plan that would reduce energy consumption and the hospital's overall carbon footprint. Already in place was a water management program that Energy Integrators, Inc. had developed for the hospital. To develop a holistic utility management program, the energy firm first conducted a baseline energy review looking at 10 key areas of energy management. The second step was to conduct a plant review to identify both potential technical as well as operational improvements. The identified actions were prioritized and rolled out as a series of 90-day plans. This "total systems approach" gave hospital officials a comprehensive fix that substantially increased the benefits for the hospital as a whole.

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"People often look at energy management as a technical fix of simply changing out a chiller or upgrading the lights," said Green. "Our goal is to establish a systems approach to facility management— that is, integrate the operational, technical and environmental issues into the overall management systems of the facility. The HVAC project was one key element of an overall strategic plan to reduce energy and the hospital's carbon footprint.

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