Health researchers study alternative ventilation methods and their implications for infection control. Architects tinker with the quantity and position of window glazing to maximize views, and to offset heating, cooling, and lighting costs. Likewise, lighting designers add controls to balance daylighting schemes with hospitals’ significant demand for electric lighting. Engineers explore the possibilities of geothermal heating and cooling solutions and on-site power generators. Finally, roofing experts look more closely at the energy- and water-saving benefits of green roofs.

These are but a few examples of solutions that hospital executives, facility managers and designers are working to employ as energy costs — and patient needs — rise.

1. Displacement Ventilation Lowers the Number of Air Changes

A recent study conducted by Mazzetti & Associates and Stantec, West Coast-based engineering and A/E consulting firms, respectively, explored the possibility of replacing traditional overhead ventilation with displacement systems. They hypothesized that this would lower the number of hourly air changes in a hospital waiting room and a patient room.

Currently, the American Institute of Architects (AIA) Healthcare Guidelines require 12 air changes per hour. Reducing this number in waiting rooms — to six and eight per hour — would require far less power from the hospital heating, ventilating and air-conditioning (HVAC) systems. However, would the newfound energy efficiency lead to failure in the hospital’s infection control system?

The researchers’ preliminary conclusion is no: A displacement ventilation system could indeed operate at a lower number of air changes per hour than a conventional ventilation system without affecting “comfort, ventilation effectiveness and particle control.”

In other words, early tests have looked promising, but more research is necessary. A group called the Healthcare Ventilation Research Collaborative (HVRC) is currently conducting Phase II research into the question. Ultimately, they hope the answers will foment change in the current design guidelines.

Sunshades at St. Joseph’s Hospital and Medical Center BNI Tower in Phoenix reduce heat gain from direct sun and reduce glare, leading to greater occupant comfort. >> Photo by Mark Delsasso, Delsasso/Visus LTD.

2. Balancing Window Areas, Views and Energy Management

Numerous studies have shown that natural light both speeds patient recovery and contributes to employee productivity. Hospital designers take this into account when they design patient rooms and staff areas with wide expanses of glass and external views. But what is the balance between productivity and healing on the one hand, and energy efficiency on the other?

The basic design rules say that glazing should be minimal on the east and west exterior walls of a building, and maximal on the north and south walls. It is possible, however, to add more glazing to this basic formula by blocking direct summer sun through exterior horizontal shading devices. Additional shades in the form of overhanging shelves on the building interior (although configuration must address infection control), along with conventional shades and curtains inside, can also help. In fact, a new, energy-efficient roller shade has been introduced to market. A mesh, it’s equipped with electronics that track the sun and cause the shade to lower and rise depending on the sunlight’s strength.

Energy modeling for the Rush University Medical Center, Chicago, showed that the quantity of glazing had the largest impact on the required air volume for patient rooms. Reducing this quantity, from the original design of floor-to-ceiling glazing across the entire exterior wall down to a large window opening with a clerestory, reduced required air volumes. The change resulted in acceptable patient comfort and still maintains significant access to daylight for a healthy environment.

Rush University Medical Center (www.rush.edu) is a non-profit, academic medical center that encompasses a 613-bed hospital serving adults and children, the 61-bed Johnston R. Bowman Health Center, and Rush University. In 2007, Rush was named a “Top-Performing Hospital” by University Health System Consortium (UHC), an alliance of 102 academic medical centers, which placed the facility among the top five medical centers in the nation for the third year in a row. Rush University is home to one of the first medical colleges in the Midwest and one of the nation’s top-ranked nursing colleges, as well as graduate programs in allied health, health systems management and biomedical research.

3. Apply Interior Lighting Controls

It’s possible to pull all available daylight into a building, but to have an impact on energy savings, the daylight must then be controlled. In other words, glazing and shades are a good start, but naturally lit rooms still need dimmers to adjust the electric lighting as the available daylight changes.

In a hospital that seeks to make an impact on energy consumption, it’s important to challenge standard assumptions about lighting, especially with regard to 24/7 operations. One of the best ways to accomplish energy savings and still allow for task needs is to install a combination of ambient and task lighting in patient and exam rooms, as well as nursing stations. In a patient room, for instance, a bright light focused on the patient can be turned on only during examinations, but remain off the rest of the time.

Primary lighting is thus provided at lower ambient levels and dimmed in conjunction with daylighting controls. Dimmed nighttime light levels can also make people more comfortable. It helps patients sleep and reduces stress on the staff—all in addition to saving energy. Designers should also look at highly energy-efficient fluorescent lamps that have lower wattage and require fewer lamps per fixture, rather than use a conventional design with lower light levels.

Other good places to reduce light levels are areas that don’t require high visual acuity, such as corridors and waiting rooms. In general, lighting should be customized according to departmental functions. Higher lighting levels are necessary in ER examination bays, but not in staff areas or imaging rooms. In rooms where patients are less likely to perform visual tasks, such as the ICU, ambient lighting could also be lowered.

Great River Energy’s facility in Maple Grove, Minn., illustrates displacement ventilation, as in use in its headquarters facility. Tate Access Flooring is shown in this example. >> Photo by Don Wong.

4. Consider Geothermal Power

Geothermal systems operate on the principle that the temperature of the ground under the earth’s surface is constant: 50 degrees Fahrenheit, or 10 degrees Celsius, year round. Geothermal systems typically pipe liquid through a well. In the winter, the earth itself warms the liquid, and the transferred heat will heat a building. During the summer, cool underground temperatures warm water from the surface; that transferred energy will cool a building. Thus, a building that uses geothermal energy requires less air conditioning in both winter and summer.

Capital costs can make geothermal systems expensive to install, but heating and cooling equipment could be downsized. On the other hand, hospitals are designed to last five or more decades, and are owner-occupied. In that context, it makes sense to evaluate a major geothermal system in terms of lifetime, rather than acquisition cost.

5. Generate Power OnSite

Transmitting power from a power plant results in energy loss along the way. Moreover, the ratio of energy used to produce the power, compared to what a hospital receives, always indicates significant inefficiencies.

An onsite cogeneration plant that produces both electricity and heat can eliminate those inefficiencies. Such a generator requires natural gas or oil as fuel to produce electricity. Heat, a byproduct of the process, can be used to produce hot water or steam for the facility. Savings include the costs of transmission losses and the electricity formerly used to heat water.

6. Grow Grass on the Roof

Widely used in Europe for years, green roofs offer several benefits. First, a green roof saves energy by providing insulation and lowering intake temperatures, so cooling equipment doesn’t need to work as hard. Second, grass and soil protect roofing membranes from ultraviolet radiation, which causes the membranes to deteriorate. Third, green roofs retain rainwater, reducing stormwater infrastructure. Finally, green roofs are more pleasant for patients and staff to look at. Studies have shown that views to nature can reduce both the need for pain medication and recovery times; these reductions have positive impacts on operating costs. Some green roofs, in fact, serve as amenities, offering walkways, meditation spaces, and opportunities for horticultural therapy. Studies by Ulrich and Cooper-Marcus and Barnes found restoration from stress, including improved mood, among patients, staff and visitors who had access to hospital gardens.

Further Considerations

Many more techniques than those six ideas exist to save money. For example, triple-paned glass may be an improvement over the double-paned glass that most hospitals have used for years. Furthermore, radiant heating and cooling in the form of chilled beams separate temperature control from ventilation air. These systems are widely used in Europe, but face some regulatory challenges in the United States. Temperature control systems such as this can mesh well with a hospital’s need for infection control.

Engineers commission new buildings by tuning up the equipment, including all energy-intensive systems, to ensure their efficient and interactive operation. Why not hire an engineering or commissioning firm to recommission an existing hospital to wring out the inefficiencies? The payback period is on the order of months versus years due to significant operational savings.

The takeaway message here is this: Sustainable design strategies produce operational, and possibly first-cost, savings that positively impact the bottom line for most any facility.