NASA Sustainability Base uses state-of-the art technology for mech. systems

MOFFETT FIELD, CALIF. — The NASA Sustainability Base, a two-story, 50,000-sq.ft. office building, named in honor of the Tranquility Base of the Apollo 11 moon landing, is designed to incorporate some of the agency’s most advanced intelligent control technologies originally developed to support NASA’s human and robotic space exploration missions. The structure is using a geothermal system, a roof-mounted photovoltaic system, solar thermal system, and an upgraded version of the water purification system that is currently on the Space Station.

The building is designed to achieve U.S. Green Building Council LEED Platinum new construction certification and will have zero-net energy consumption and use 90% less potable water than conventionally built buildings of equivalent size.

State-of-the-art technology

According to NASA Ames Research Center Associate Director Steven Zornetzer, the photovoltaic roof mounted system will produce about 35 kWh in maximum production. The panels are by SunPower and are the highest efficiency panel the company produces.

“The building is on the Ames grid,” explained Zornetzer. “We have two sources of on site power generation: one being PV and the second being the first installation of the second generation Bloom Box Hydrogen Fuel Cell. The PV will put back into the grid about half to two-thirds of what the building takes from the grid. If the building is not drawing peak power the percentages will differ. That’s our general estimate.

“The Bloom Box Hydrogen Fuel Cell will produce up to 200 kWh 24 hours a day, seven days a week,” added Zornetzer. “When both these systems work it will produce more than 235 kWh while the building is drawing 60-70 kWh. The net difference is a positive energy profile for the grid. We are putting back about 130 kWh and 150 kWh back into the grid. It’s clearly a net-positive site.”

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In addition to the Bloom Box Hydrogen Fuel Cell and roof-mounted PV system, a solar thermal system produces domestic hot water.

“Solar hot water panels on the roof will offset 60% of domestic hot water generation demand,” said Richard Ross,construction manager at AECom, which is providing program management, space planning, architectural design, structural and civil engineering and LEED consulting services for the Sustainability Base. “And a potable water use reduction of 87% over a conventional installation is expected by the use of campus recycled water for irrigation, grey water recycling and the use of low-flow fixtures.”

For HVAC, Boneso Brothers Construction, Paso Robles, Calif., installed a closed-loop geothermal system with 106 wells 140-ft. deep each and spaced at 20-ft. centers, and radiant cooling ceiling panels are used throughout the building.

According to Ross, there were a number of reasons why a closed-loop geothermal system was deemed suitable for Sustainability Base: a parade ground adjacent the site could be used for the geothermal loops, eliminating any concerns about construction over the top of the loops; the bay location was ideal for the system, as tidal ground water flow beneath the surface ensured any heat rejected from the building to the soil was removed; and the mild water temperatures from the geothermal loop (around 60ºF) would work ideally with the proposed chilled ceilings.

“The chilled ceiling panels were suspended directly from the concrete deck, positioned to coordinate with lights, sprinkler pipe work and heads, and to leave space for future installation of partitions at pre-determined locations,” said Ross. “This design gave NASA managers their required space-planning flexibility.”

“These ceiling panels are used more in Europe than the U.S., said Zornetzer. “It’s a very simple system. Panels are approximately 7-ft. or 8-ft. wide and 20-ft. long each. They are situated so they cover the entire ceiling space of the first and second floors. On the side of the panel that you can’t see is an extensive network of copper tubes connected via water lines to pumps that pump the cool water year around, and is circulated through these copper tubes on the backside of the panels. Since cold air is denser than warm air, as the water circulates, the air surrounding the copper tubes cools and the cooler air trickles down to the floor space below. Benefits of the ceilings panels are no Freon or filters, and not much maintenance needs to be done, plus, it’s a completely silent system.”

Ross points out that with chilled ceilings, care must be taken with chilled water temperature to ensure condensation doesn’t form on the ceiling.

“The water temperatures from the geothermal loop are ideally suited for this application,” said Ross. “Because Sustainability Base has operable windows, there is also a risk that outside air could condense on panels under certain conditions if the windows were left open. To ensure optimum control of chilled ceilings, wet bulb temperature sensors were installed at strategic positions across the floor to send signals to the chilled ceiling panel control valves. Chilled ceiling cooling outputs are lower than for a conventional variable air volume or fan coil unit system. Thus, chilled ceiling systems are best suited for buildings with low internal heat gains.”

When asked if there were any challenges, Zornetzer said, like in any project, there are always some challenges.

“The geothermal was designed to be deeper with fewer wells,” said Zornetzer. “The test wells were all good, so we started laying out the matrix of wells and we hit an aquifer, so we had to go back and redesign the well field, but there were lots of little things like that, but nothing was a show stopper.”

Water conservation

According to Zornetzer, the building, including the landscaping areas, is supposed to use 90% less water than other office buildings of the same size. Boneso Brothers installed the building’s dual plumbing system along with all low-flow plumbing fixtures.

“We have a 6,000-gal. tank onsite that was buried and every evening the tank gets refilled by reclaimed water, and this is used to water landscaping,” said Zornetzer. “We are saving water that would have gone into the bay nearby. The building also contains a NASA developed water purification system that is currently on the Space Station, providing astronauts with water by recycling every bit of water generated on the Space Station, including condensation, urine, and wastewater.

“We took a slightly upgraded version of that system and expanded it in size to accommodate this building and take all the hygiene water in the system and use it for flushing in the building,” explained Zornetzer.

Intelligent controls

Another NASA technology utilized in the building is the Intelligent Adaptive Control System, composed of software modules that have been developed for aerospace applications.

“We are bundling them together, having them work for the first time in a building on the planet,” said Zornetzer. “Here’s my vision of what will happen: the system will go out and do data mining. It will look for the weather forecast for tomorrow and know specifics. It will also know that the conference room will be used by 50 people at 10 a.m., so the control system will make a prediction that it needs to turn on the pumps to the geothermal wells for the conference room, then it will know to shut down pumps after the conference so energy is not wasted.

“At the end of the conference, the computer system will have monitored throughout the conference how close to its predicted temperature setting it wanted to achieve. It will measure that, from the actual performance that was achieved, and it will readjust its algorithms, so it’s learning from its own performance.

“Additionally the computer system will be monitoring in real time the environment throughout the building all the time, so it monitors the temperature, the light conditions, the air currents in the building, and it has a number of controls to change those parameters if they are not right.”

The system is able to open or close windows to let in more or less fresh air, depending on weather outside; raise or lower window shades if too much heat is coming in or not enough; and it will actively monitor the mechanical systems in the building.

“We will also establish the vibration patterns of the pumps when they are operating,” explained Zornetzer. “By constantly comparing the vibration patterns of the pumps over time we can predict when the performance is degraded, indicating when the pumps need servicing or a bearing may be going bad, etc. Instead of having scheduled maintenance we have maintenance on demand when required, which should cut down on maintenance costs dramatically.”

When asked how these technologies will help NASA to develop a base on Mars, Zornetzer told CONTRACTOR that the more we learn about how to operate and automate these building control systems the more we will be able to develop and adapt those technologies in habitats elsewhere.

“We are partnering with Johnson Space Center with the water purification system,” said Zornetzer. “They are interested in different things about the system, so this informs them about the future application of the system on a larger scale effort like a habitat on Mars. As important as it is to be able to apply such technology back to NASA, I think that once we demonstrate that these technologies can work, and we have perfected them, we can license them to the private sector and let them develop these technologies for buildings elsewhere, so others benefit.”