LifePoint Hospitals’ new Clark Regional Medical Center (CRMC) in Winchester, Kentucky, opened in April 2012, becoming the first hospital in the state to run on a 100% geothermal heating and cooling system (For more on the project, see Healthcare Building Ideas article "Bluegrass Building").
The engineering team behind the project was CMTA Consulting Engineers, which partnered with Stengel Hill Architecture and LifePoint to bring the idea of geothermal to reality.
“CMTA’s been doing this for a long time, but LifePoint called on us to present something to them that was new and innovative, and an energy-efficient design. And this is what we all, as a team, came up with,” says Kevin Sandrella, PE, LEED AP, electrical engineer with CMTA.
When first considering an appropriate type of HVAC system to use at the 79-bed CRMC, geothermal quickly rose to the top of the list, thanks largely to the geography of Kentucky, which consists greatly of underlying rock, says Chris Malicki, AIA, LEED AP BD+C, principal on the CRMC project for Stengel Hill.
Rock, Malicki adds, is a great heat sink, with consistent temperatures year-round. Rock is also easy to drill, which makes a project cheaper to undergo and the system itself more cost-effective to pursue.
However, for hospitals across the country—specifically outside of Kentucky—there are a number of additional issues to consider when undergoing a geothermal project, as well as challenges specific to healthcare that must be combated.
The basics
While the use of geothermal isn’t necessarily new to healthcare, Malicki says oftentimes systems are used in combination with normal air handling units. So when it comes to pursuing a 100% geothermal project, there are a few basic components that need to be in place.
First is having the right site.
“We’ll drill an initial test drill to determine if the soil is right. These wells are about 400 feet deep, and it really takes the right combination of layers of dirt, rock, water, and the right strata to be able to drill those wells and get the thermal transfer to and from the earth that you need,” Sandrella says.
The next consideration is whether there is enough room on the site to drill all the wells necessary. For the CRMC facility, 217 wells were drilled.
However, using geothermal in healthcare is particularly challenged by spaces like the OR, where very specific air filtering requirements must be met, such as the static pressure required for final filtration. To find a solution, the team turned to its vendors.
“One of the manufacturers put together a package, which is what we ended up with at CRMC, where they took their standard heat pump and put an extra fan module on top that was capable of achieving the extra static pressure that we needed to get through the final filtration,” says Douglas Hundley Jr., PE, LEED AP, CxA, mechanical engineer for CMTA.
Temperature itself must also be maintained in the OR, which is generally kept cooler than elsewhere in a facility at 65 to 68 degrees Fahrenheit. If cooled with a standard discharge temperature of 55 degrees, the relative humidity will go up.
“You have to maintain a minimum relative humidity in a space or you start to have issues with paper sticking together or something like that, so we had to get a lower discharge temperature off the units to be able to do that efficiently,” Hundley adds.
While there are challenges, a big reason why geothermal tends to be an efficient mode of heating and cooling is that, if applied properly, it can eliminate the constant reheating of air often found in the healthcare setting.
“You spend so much energy in reheat; you cool the air down and then you just reheat it,” Hundley says. “When you break it up individually into multiple heat pumps, we’re never reheating with our heat pumps.”
Design considerations
Just like the space on the site itself that must be available for drilling, a facility must also have space for the equipment needed to run a geothermal system.
“It is a little bit space-intensive in that you need space to install all these individual heat pumps. In order to solve that and not take up valuable square footage within the footprint of the building, we chose to go with a penthouse organization where all of the heat pumps themselves are located above the areas they serve in an individual penthouse, which of course is shielded from the weather,” Malicki says.
The design also lends itself to easy access for maintenance without disrupting the daily flow of business. “Everything can be taken care of out of sight,” he says.
Another important design element is incorporating an efficient, thermal building envelope.
“I think that’s something we really achieved here. We used an above-average super-insulated envelope in that we used an innovative spray-applied polyurethane insulation in the walls, a kind of expanding foam insulation,” Malicki says.
Coupled with that is a roof installation of lightweight insulated concrete that was poured and then topped with insulation in the roof membrane, as well.
“A third element would be a real efficient UV glass, which limits your heat gain throughout the facility. I think all of these envelope considerations that we took into effect really helped out the geothermal system and really adds to the energy savings,” Malicki adds.
Maintenance
While installing a geothermal system is just the first hurdle that needs to be cleared, Malicki says the maintenance of the system can be easily managed. One way this was tackled on the CRMC project was through standardization, particularly in the filters used.
“It’s maintenance-friendly in that each individual heat pump unit is served by one type of filter size. They’re all basically utilizing the same parts, so it’s just a kit of parts that’s repeated over and over again,” he says.
However, beyond size is also the grade of filter, and going up to a higher grade is something Hundley stresses should be discussed with ownership.
“That’s when the price you pay for the premium on the filters is more than compensated for in the energy systems, but it’s one of the things you want to make sure is understood upfront so [the owner] is not surprised at the end of the job,” he says.
At CRMC, there also is a good amount of flexibility built in, with temperature controls for individual rooms.
“When one of the units goes down, it’s limited in area. You’re not shutting down an entire patient wing, for instance, to service one unit,” Malicki adds.
The payback
When pitching a project that requires a significant upfront investment to ownership, it’s likely the word “payback” will come up. And in the case of CRMC, the point when the initial cost will be recouped is expected to be in under two years.
Sandrella says CMTA has worked on a number of geothermal projects, including schools and medical office buildings, which formed a basis for predicting payback on the CRMC project.
“Based on all that past research data, we estimated energy usage for this facility, and we think it’s going to bear out pretty close to our estimates,” he says.
However, undergoing such projects will also likely open the door to tax credits and incentives. CRMC CEO Kathy Love says in this case, the savings brought the project payback to 10 months, in addition to the ongoing monthly energy savings.
However, for an administrator, there are concerns beyond cost that include basic requirements for how a facility is operated.
“You have all your concerns and fears that you’re not going to get the OR at the temperature you need or if it’s going to work, but I can honestly say that never having to think about a boiler or chiller again is not something I’m going to lose sleep over,” she says. “We are very pleased with the temperature controls and the humidity levels, all of the things we hold very true for licensure and regulatory matters.”
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