-By Stephen J. Wernersbach, P.E, and Daniel R. Dickenson, P.E., LEED AP

In spite of the current reprieve from spiking energy costs, the trend toward sustainability—and particularly energy-use reduction—continues to gain attention among engineers serving the healthcare sector. But energy reduction isn’t the only issue in the broader sustainability movement. Visionary industry leaders, engineers, and system manufacturers are working hard to connect sustainability to health, which brings global warming and other “green” factors into play.

Significant Benefits
McGraw-Hill Construction, in conjunction with Turner Construction Company, the USGBC, and Johns Manville, conducted a study on green building in the healthcare construction sector. The study’s major findings indicated important benefits including:
• Green healthcare facilities reduce energy use, thus reducing green house gasses and improving air quality.
• 47 percent of respondents said that patient recovery time is reduced in green buildings.
• Other benefits include lower operating costs, greater innovation and improved public relations.
• The survey clearly shows that there is an increasing trend toward building green healthcare facilities. Of the survey respondents, 19 percent said they expect that their organization will be significantly involved with green building, more than triple the level from the previous year.

Opportunity to Make a Difference
Because today’s healthcare facilities are significant consumers of resources, they provide an excellent opportunity for engineers to introduce changes that reduce resource consumption and serve as sustainability models. Constructing a green facility involves following guidelines, such as LEED, the nationally recognized green building rating system developed by the USGBC.

The problem in the healthcare sector is that LEED does not easily apply to medical facility projects. The codes require minimum air change rates and filtration levels in different areas of the facility. This places healthcare facilities at a distinct disadvantage in meeting LEED energy guidelines.

Presently, a healthcare package is in development that would make it more feasible for healthcare building projects to achieve certification. To help remedy the problem, American Society of Healthcare Engineering (ASHE) developed a “Green Guide for Healthcare,” based on the USGBC LEED numbering system, which is being used to modify the non-healthcare LEED standards.

As a leading healthcare architectural and engineering firm, Ellerbe Becket is constantly exploring the latest developments in energy-efficient building products and systems. One of the more innovative products that we use for applications such as operating rooms, where low temperatures make humidity control both difficult and fairly energy intensive, is the Trane CDQ Air Handling Unit.

Enhanced Dehumidification
The Trane CDQ desiccant wheel enhances the dehumidification performance of a traditional cooling coil. The wheel is configured in series with the coil so that the "regeneration" side of the wheel is located upstream of the coil, and the "process" side of the wheel is located downstream of the coil. The CDQ desiccant wheel adsorbs water vapor from the air downstream of the cooling coil, and then adds it back into the air upstream of the coil, where the coil through condensation removes it. This occurs without the need for a second regeneration air stream.

Some of the benefits include:
• Increased cooling coil latent (dehumidification) capacity
• Lower supply air dew points
• Decreased need for reheat
• Lower unit cooling sensible heat ratios (SHR)
• Warmer required chilled-water temperatures
• Decrease in the required cooling capacity when dehumidifying
• Exhaust air not required
• All electric system eliminates need for expensive gas heat

Large Heat Pumps Enable Innovative Solutions
Heat pumps are nothing new, and we know they can heat and cool air at substantially lower costs than traditional gas and oil systems—under the right circumstances. But with the exception of the old Westinghouse Templifier industrial-sized heat pump—the precursor of modern versions—manufacturers mainly offered heat pumps only in small capacity models, which limited their use.

New higher capacity water-to-water heat pumps from manufacturers such as York are enabling innovative new applications in the healthcare sector. Besides providing one piece of equipment that can simultaneously heat and cool, the York model uses waste heat to cut water-heating costs as much as 50 percent and has COPs that are as much as 500 percent higher than fossil-fuel water heaters

The heat pumps are excellent for meeting the challenging requirements hospitals and medical center’s face in exchanging air six times per hour in patient rooms and 20 times or more per hour in operating rooms. The full-size chillers now available can handle both heating and cooling requirements with lower energy consumption in warmer climates.

These and many other products and systems are contributing substantially to achieving the overarching goal of sustainability and energy-use reduction in the healthcare sector.

Stephen J. Wernersbach, P.E., is a director of mechanical engineering, and Daniel R. Dickenson, P.E., LEED AP, is a principal and director of mechanical engineering, at Ellerbe Becket in the Minneapolis office.