PUD Engineer’s proposal wins national crowdsourcing contest
A breath of fresh air is always nice, but too much of it can result in wasted energy that’s costly to owners of commercial buildings.
A proposal from PUD Engineer Jim White to use carbon dioxide monitors to help control air volume in buildings got the nod from the Oak Ridge National Laboratory, winning the lab’s Buildings Crowdsourcing Community Campaign last month.
White, a Senior Energy Efficiency Engineer with a PhD in mechanical engineering, won in the Sensors and Controls category for his design for variable air volume (VAV) mixing boxes. His design combines temperature and carbon dioxide sensors to control outside airflow settings of individual VAV boxes. It could yield significant energy savings while improving air quality.
A model of the concept was 3-D printed and exhibited at the lab’s Industry Day on September 24.
‘A kid in a candy store’
White said he felt like “a kid in a candy store” at the conference, which featured displays and demonstrations of scientific advances. For example, White said he watched a clothes dryer technology that uses ultra-high frequency sound vaporize water from clothing in seconds. This could be used to quickly dry clothes at the end of a wash cycle, eliminating the need for a separate dryer.
Now that’s something we can relate to.
Unless you’re a building scientist or operator, White’s innovation seems a little more obscure. But it has the potential to reduce energy use in buildings significantly.
White’s idea will be put to the test at the PUD’s Headquarters Building this winter, where he expects to cut energy consumption by 20 percent. That’s in addition to a 35 percent drop in energy use from earlier improvements made at the office building on Wenatchee Avenue.
How does the carbon dioxide theory work?
Humans emit carbon dioxide as they exhale, White explained. Carbon dioxide sensors can be used to indicate how much ventilation is needed for any given space. Instead of setting air flow at a fixed position, which can cause the space to be over air-conditioned, CO2 sensors can be used to vary the volume of air based on actual ventilation requirements – what those in the room need to be comfortable and refreshed.
Keeping your cool
Tying air flow to carbon dioxide should eliminate over-ventilation and excessive cooling, which wastes energy. “This will still give the ventilation that’s needed, but allow for optimum levels,” White said.
Demand Control Ventilation is not new, White said, but using CO2 monitors in conjunction with individual VAV boxes has not been done elsewhere.
The PUD’s heating, ventilating and air conditioning (HVAC) uses a system commonly found in large commercial buildings. A large rooftop unit supplies a mixture of fresh and return air at 55 degrees to individual VAV boxes. A thermostat controls the damper in each VAV box to vary the volume of 55-degree air that is supplied to each zone. If the space does not need air conditioning, the VAV box could shut off the flow of 55-degree air to the space, but this would also stop the flow of fresh outside air. To make sure there is enough fresh ventilation air to the space, the VAV boxes are normally set to provide at least 20 percent to 30 percent of the maximum air conditioning needs of the space at all times.
If that amount of 55-degree air is too much, electric heaters will often come on to reheat the previously air-conditioned air. Depending on the season, this can waste electricity and make the space uncomfortably cool. Using a CO2 sensor to control the minimum air flow setting will reduce the amount of over-cooling, while also making sure the space is not over- or under-ventilated.
Oak Ridge National Laboratory launched its crowdsourcing platform in March so innovators like White could present ideas for energy efficient buildings to private and public sector leaders in research and development. The goal is to bridge the gap between cutting-edge ideas and the marketplace.
White presented his concept at the conference and took part in a panel discussion with two other winners and an official from GE.
White has been with Chelan PUD for 17 years, where he manages the PUD’s commercial and industrial energy efficiency program. Through his Resource$mart program, local businesses have saved thousands of dollars in energy costs. Prior to coming to Chelan PUD, White worked as an energy efficiency consultant at PacifiCorp and Portland General Electric, and as a staff engineer at the Governor’s Energy Management Center in Texas. He is a former board member of the Solar Electric Power Association and the architect of Chelan PUD’s award-winning Sustainable Natural Alternative Power program.
The Oak Ridge National Laboratory in Oak Ridge, Tenn., is the U.S. Department of Energy’s largest science and energy research facility. The heat pump water heater – a relatively new product promoted by Chelan PUD – was designed and tested at the lab and is manufactured in the U.S.