十月 24, 2013

Looking at the numbers and accolades surrounding Methodist Olive Branch Hospital (MOBH), you might assume that the project’s costs and construction schedule far exceeded that of an average small hospital. The 100-bed hospital in Olive Branch, MS is projected to receive an Energy Star rating of 95 and is on track to be the world’s first hospital to earn the LEED Gold for Healthcare Certification. It is one of only a handful of hospitals nationwide to feature a state-of-the art geothermal heat pump system, and to include photoelectric glass, which automatically adjusts its tint based on sunlight levels. Perhaps most remarkably, all of that was achieved on a budget of $100 million ($317/sf) and ahead of a fast-track, 24-month schedule. In this post, I would like to take a look at two major design elements that made those achievements possible- the geothermal HVAC system and the specialized glass and lighting system.

 

 

Geothermal Heat Pump

Methodist Le Bonheur Healthcare challenged the Integrated Project Delivery (IPD) team of Gresham Smith, Smith Seckman Reid and Turner Construction to create an innovative hospital that reflects the organization’s exceptional commitment to sustainability. Our team carefully evaluated a number of HVAC systems to determine the most energy-efficient and cost-effective option, and ultimately selected a ground source heat pump system supported by an on-site geothermal bore field. MOBH is among the first in the country to use such a system.

 

 

By The Numbers

  • 7X: Water is roughly seven times more efficient than air at transferring energy, allowing MOBH to realize tremendous energy savings over traditional air handler/VAV systems
  • 124 vs. 245: MOBH earned an Energy Use Intensity (EUI) of 124 kBtu/sf, versus 245 kBtu/sf for a typical hospital.
  • 25%: The geothermal strategy is projected to return an annual energy savings of 25% with a 5-year return-on-investment.
  • 14′-4”: Spatially, the system eliminates the need for chillers, boilers and air handlers and dramatically reduces ductwork. While the addition of the closets slightly increased the overall square footage, the elimination of main trunk ducts allowed us to reduce floor-to-floor heights to 14′-4”, ultimately making the strategy more economical.
  • $216,000: The ground source heat pump system alone will save Methodist $216,000 a year in operating costs.

 

 

Specialized Glass and Lighting Systems

As we continued to seek out green design innovations, we discovered one right in the hospital’s backyard. A local manufacturer had just begun producing photoelectric glass, and MOBH is a pilot showcase for the product. The two-story lobby is glazed with dynamic, photoelectric glass, which changes from clear to opaque based on the amount of sunlight hitting light sensors mounted on the lobby roof. This reduces glare and solar gain and reduces the amount of energy needed to heat and cool the large space.

 

 

Electrical lighting in the lobby is controlled by an automated system that maintains an appropriate level of footcandles to ensure that electricity is available when it is needed and conserved when it is not. The footcandles automatically dim as daylight provides adequate ambient light and brighten as the windows darken.

To further reduce solar gain, we reduced the width of the typical patient room window and opted instead for two windows of standardized sizes. This allowed for the same amount of natural light, but significantly increased the glazing-to-frame ratio. The windows were also recessed an additional 7 inches, allowing the façade itself to act as a sunshade. These strategies resulted in a 22% decrease in the amount of direct sunlight hitting the glass, dramatically reducing solar heat gain in all patient rooms.

Overall, these sustainability strategies contributed to achieving 18 EA cr.1: Optimize Energy Performance LEED points, and an annual energy cost reduction total of $318,000. They also contribute significantly to the patient experience. With the geothermal pumps located in their rooms, patients can enjoy more personalized control over their environment, which, according to several evidence-based design studies, helps to lessen anxiety and improve healing. Adjustments to windows and the glass used in them help to avoid uncomfortable heat buildup or troubling glares, without negatively impacting patient’s exposure to natural light and outdoor views. Each of these factors plays a role in achieving Methodist LeBonheur’s ultimate goal of creating the best possible patient experience for the residents of Olive Branch and ensuring that they no longer have to drive across state lines to find convenient and high-quality care. Personally, I can say this was one of the most enjoyable projects I have worked on- every member of the IPD team was committed to creating a smart, sustainable, cost-effective facility and I am very proud of the end result.