U.S. Department of Energy - Energy Efficiency and Renewable Energy
Building Technologies Office
Hospital Energy Alliance: HVAC—Kaiser Permanente Video (Text Version)
Below is a text version of the Hospital Energy Alliance HVAC video about the use of innovative HVAC concepts at the new Kaiser Permanente Hospital in Modesto, California.
Kaiser Permanente sought cost-saving approaches to ventilation in the construction of one of its new California hospitals.
We had a lot of questions about, how could we reduce our overall energy take in a hospital environment? Went to Mazetti, asked them, what was technically feasible? How might they approach a study relating to either natural ventilation, or a new ventilation technique that would be different from the traditional way of supplying air to a hospital environment.
Natural ventilation allows us to turn down our mechanical ventilation and not use as much fan power, as much chiller energy, and as much boiler energy because we're able to take advantage of the outdoor air conditions.
The biggest concern is really the infection control issue and so when we look at kinds of buildings, we have to look at the kinds of spaces and the ways that the patients present themselves and what kinds of airborne transmissible disease really is in that space.
Kaiser also focused on another HVAC concept: displacement ventilation.
We're looking at ways where an individual hospital can radically increase the comfort of the room occupants, reduce infections, and also save energy at the same time. Displacement ventilation seems to have the potential of doing all three of those things.
Most ventilation systems used in the U.S. introduce air at a ceiling level and they blow large volumes of air into the room and rely on mixing of the air. Displacement ventilation introduces air at a lower level and uses different principles at different volumes and different temperatures and has the air rise and be exhausted out the ceiling.
We can use slightly lower ventilation rates because we've decoupled ventilation from thermal performance. We can now go to four air changes an hour rather than six air changes an hour. We can increase the comfort level of people in the space because they don't have a lot of air mixing going on. And we can actually improve the air quality from an infection point of view.
We did a certain level of analysis; enough to show us that it was a viable technology, that it could save energy, that it could save cost.
Phase two of our effort was focused more on going into the level of detail required to influence codes.
We used the Modesto Medical Center as a place where we could test—in an actual patient room—the difference between a traditionally delivered HVAC system, and a displacement system. We wanted to use Modesto because it was one of our newest hospitals, opening in a few more months, so it gave us the opportunity to get into the hospital to test the system in a non-patient environment. And then once patients were there, we could actually test it without disturbing the patients.
The results of the study proved that we could maintain thermal comfort, ventilation effectiveness, and contaminant control at the reduced air changes while saving energy and also improving the patient experience.
Kaiser Permanente has a number of new hospitals that will be coming up in probably the next five to six years. Those are all hospitals that we would very seriously consider, from the very beginning of the design, implementing displacement ventilation, and perhaps natural ventilation as well.