Berkeley Lab’s Rick Russo—a pioneer in the field—has been working with a technology called Laser Induced Breakdown Spectroscopy (LIBS), refining and expanding the technology for many applications. Famous for its use on Mars by the rover Curiosity in 2012, LIBS uses a laser beam to vaporize a small sample of material (called laser ablation), then uses a telescope to view the vapor, or plasma, and then uses a spectrometer to analyze the light emitted from the plasma.

Since every material has a unique spectral signature, thanks to its chemical components, this “light signature” is like a fingerprint, allowing researchers to identify components in the material.

Out of this research at Berkeley Lab was born another technology called LAMIS—or Laser Ablation Molecular Isotopic Spectrometry. Both LIBS and LAMIS use laser ablation to analyze samples in just a few seconds. But where LIBS only measures the optical emission spectra of atoms and ions, LAMIS measures the emission spectra of molecules and molecular ions. This enables LAMIS to identify the specific isotopes of a chemical element within the plasma plume. Russo won an R&D 100 award in 2012 for his work using the LAMIS technology.

Five years ago, a new researcher at Berkeley Lab, Vasileia Zormpa, joined the Energy Storage and Distributed Research Department to take their chemical imaging work even further. Based on the original LIBS technology, and refined through LAMIS, Zormpa is the first person to advance this capability to use laser ablation to analyze very small samples—on the nanometer spatial scale. 

Focusing the Beam

Taking smaller samples requires more tightly focused laser beams, the greatest challenge of this research. Basic laws of physics limit spatial resolution: light cannot be focused to dimensions lower than roughly half the wavelength of the laser beam used, which for conventional laser systems is on the order of a few hundred nanometers. To circumvent these limits, Zormpa and her team are incorporating a more sophisticated concept called “near-field optics” and combining it with ultra-fast lasers (or femtosecond lasers), which pulse at a duration of a millionth of a billionth of a second.

Near-field optics allows them to focus the femtosecond laser beams to the microscopic size of a few tens to a few hundred nanometers. Moving the laser beam very close to the sample material—5 to 10 nanometers from the sample—allows them to focus the beam very tightly, achieving high spatial resolution, which means that the laser ablates a much smaller amount of material during each pulse.

As a comparison, an average human hair measures about 75,000 nanometers, a virus measures 30-50 nanometers, and DNA measures about 2.5 nanometers.

“My job is to get the beam focused,” Zormpa said. “When the lasers interact with the surface of the material, it will vaporize a portion of the material. We are interested in how small a sample size we can take, the best spatial resolution we can achieve,” she said.

But a smaller sample size, with less vaporized plasma, creates other challenges to overcome. As the material is vaporized, it generates a tiny spark of light—a specific spectrum that is captured and analyzed. If the amount of material is very small, less light is available. Zormpa’s research looks at the most efficient way to balance the goals of focusing the beam while still being able to read and analyze the chemical information needed.

“We have been able to still get chemical information with beam sizes less than 500 nanometers, which is a world record in laser ablation optical chemical imaging,” Zormpa said. “The amount of material we vaporized was 200 attograms—a billionth of a billionth of a gram,” she said.

Why So Small?

In the past, laser ablation technologies have been used to test long-distance for explosives, test toys and paint for lead contamination, and assess contamination at hazardous waste sites—without the chemicals to dissolve samples or vacuum chambers that other sampling techniques require.

In addition, LAMIS represents what may be the only practical means of determining the geochronology of samples on Mars or other celestial bodies in the Solar System. Strontium isotope ratios have been a focus in the field of medicine for both treatment and diagnostic purposes. Measuring these ratios can provide valuable information about atmospheric chemistry. They also can be used to trace the origins and movements of early humans. Perhaps the most immediate and important application of LAMIS will be in nuclear forensics aimed at non-proliferation and terrorism.

But this new near-field technology is used in other applications that require careful and precise—and very small—samples. Over the past few years, Zormpa and her group have been applying these ultra-focused (near- and far-field) femtosecond beam technologies to analyzing solar and battery research.

For example, working with Robert Kostecki’s battery group at Berkeley Lab, Zormpa is using femtosecond laser ablation technology to help improve batteries for electric vehicles. In their research, they are studying a thin, interfacial layer on the batteries that is very important for the performance and safety of the system. Because the layer is very thin, only about 50 nanometers thick, using lasers with lower depth resolution (sampling thick slices of material at a time) doesn’t work.

“Let’s say you have a small particle, only a few nanometers wide, next to another particle, one of silicon and one of aluminum,” she said. “If you use a larger beam size, you vaporize both materials, and you don’t have a clear picture of where each individual particle was,” she said.

The main strength of the near-field ablation technology has to do with true three-dimensional imaging. Using the ultra-focused lasers, Zormpa can determine the composition of the material, how elements are distributed in the layer, and test for impurities.

“We have been successful because we were able remove thin slices with laser pulses, about seven nanometers at a time,” Zormpa said. “Each layer is analyzed so that we have a three-dimensional ‘picture’ of the elements and composition of the sample,” she said.

Zormpa and her group are also working with solar cells, developing the technology to test and analyze whether materials have impurities—which decreases the efficiency of the electricity output. And they are in the process of developing a portable tool that can provide the three-dimensional image of the constituents of materials like solar cells and batteries to help with research and development.

“Solar manufacturers want to know the concentration of impurities or dopants in the cell and their exact location,” Zormpa said. “If they know, they can figure out how to manage and improve the efficiency.”

Looking to the Future

While current research has allowed Zormpa and her team to use near-field optics to ablate smaller and more precise masses in their samples (excitation), the detection of the material’s chemical signature was based on traditional far-field optics.

“In our current work we are developing a new and unique system that allows us to both excite AND detect in the near-field,” Zormpa said. “We expect that this approach will help us improve the spatial resolution and limits of detection significantly.”

Laser Technologies Group website.

Over the past year, the D2G Lab has been testing and improving strategies and standards for demand-side interoperability, wired and wireless communications, communication architectures, devices, and monitoring and controls technologies. All of these strategies and standards are part of research that will improve the efficiency of the nation’s electric grid and the way it responds to fluctuations in demand or supply of electricity.

Responding to Electricity Demand

In fact, demand response is one of the biggest challenges faced by electric grid operators—balancing the moment-to-moment demand from consumers and industry with the shifting loads of incoming and stored electricity. Demand response can be manual, semi-automated, or fully automated depending on the market and customer choice, and customers can use advanced control systems to moderate how their facilities, equipment, or appliances respond.

As the electric grid has become more complex and diverse, automated demand response programs have been increasingly studied and tested in demonstration sites and cities and used commercially in utility programs over the last decade. Fully automated demand response does not involve human intervention but is initiated at a home, building, or facility when an external communications signal triggers pre-programmed load-shedding strategies.

In 2004, the California Energy Commission’s Public Interest Energy Research (PIER) program initially funded the DRRC, managed by Berkeley Lab. The DRRC’s research, development, and demonstration has led to a communications technology called Open Automated Demand Response Communication Standards (OpenADR), that standardizes the way demand response technologies work and interoperate within a “Smart Grid.”

“OpenADR helps manufacturers of building automation equipment design products for Smart Grid implementation, and power aggregators incorporate demand response into their work,” said Mary Ann Piette, the research director for DRRC. “OpenADR builds on more than 10 years of research to develop automated demand response technology and demonstrate it in buildings with utility, independent systems operator, customers, and commercial partners. The OpenADR specification uses open, non-proprietary, industry-approved data models—any interested party can develop products around it,” she said.

The initial goal of the OpenADR research was to explore the possibility of developing a low-cost communications infrastructure to improve the reliability, repeatability, robustness, and cost-effectiveness of automated demand response. After the formal release of OpenADR 1.0 specifications in 2009 and implementation, the OpenADR standards are taking hold in the United States and around the world:

• Hundreds of sites use OpenADR with more than 250 megawatts (MW) of electricity load automated in California.
• OpenADR version is in full-scale commercial deployment. Advanced OpenADR pilots are underway with government, utilities, vendors, and customers to evaluate high-speed communications for advanced demand response programs.
• More than 10 countries are reviewing and conducting pilot tests to use OpenADR for automated demand response.
• The OpenADR Alliance, established in 2010 to foster the adoption of the OpenADR standard, is growing with more than 100 members ranging from research organizations, utilities, controls vendors, demand response aggregators, and service providers.

Residential Research: the D2G Lab

Early in 2011, Berkeley Lab’s Grid Integration Group took the work one stop further—from commercial, industrial applications to residential demonstration through the D2G Lab at the Guest House.

“Our team has been doing other research on commercial and industrial facility grid integration and demand response and its market transformation,” Rish Ghatikar, deputy leader for the Grid Integration Group, said. “We decided to use the Guest House as a residential appliance research lab since the infrastructure we needed for the set up was there,” he said.

Demonstrations include communication between a multitude of end-use devices such as smart appliances, revenue-grade smart meters, and a home area network (HAN) gateway to receive demand response reliability pricing signals using OpenADR. Within the demonstration test bed, wireless and wired Internet (Wi-Fi), and in-home protocols and standards such as ZigBee Smart Energy Profile 1.0 and other proprietary protocols are used to interoperate with OpenADR and respond with a change in energy use.

The Guest House features appliances (heat pump water heater, refrigerator, washer, and dryer, loaned by the General Electric), an electric vehicle charger, programmable communicating thermostats, smart plugs, and dimmable LED lighting fixtures—all controlled by the HAN using DR signals and with Web-based energy visualization tools to provide information on energy choices being made during demand response events.

The Guest House’s heat pump water heater is part of the demonstration. It has two modes of heating—resistive heating (where a heating coil heats the water) for everyday operation, and a heat exchanger that is used during a demand response event. The heater uses 4,500 Watts of electricity during standard electric mode, powering down to 550 Watts using the heat exchanger during demand response events.

Like the water heater, General Electric’s other appliances; a washer and dryer, used by the guests, and a staff refrigerator, are “smart” appliances that communicate and switch to low-power operations in response to demand response signals.

The Guest House also features an electric vehicle charger by Coulomb Technologies, which will switch to lower charge levels during a demand response event. Before and during the demand response event, a message is displayed on the charger’s screen letting consumers know what is happening and if they have to take any action.

Ghatikar and his team have preprogrammed all of these appliances to operate in a low-power-using mode when test signals are sent to emulate a demand-response event.

D2G Lab Residential Demonstration Activities

Communication and Monitoring

“Smart” appliances are one piece of the puzzle, but the way information moves between consumers and the electric grid—and the way it can be viewed and monitored—is the foundation for demand response success. The D2G Lab is demonstrating and testing a variety of communication architectures including the Energy Service Interface, a generic interface between the service provider and the customer that can be a Smart Meter, a gateway or devices in residential settings, building management systems for commercial buildings, and energy management and control systems for industrial facilities.

OpenADR signals are used at the D2G Lab, and can be sent over a variety of networks and transports (including the Internet) from a variety of entities (including the utility). Once the demand response event signal is sent, the appliances and equipment respond by changing the power use for a short period of time. Customers can always override the changes and continue using the appliances normally, though likely at a higher energy cost and compromised reliability of the electricity supply.

These signals are monitored, and energy usage information for each appliance and end-use device is collected (for example, at 10-second intervals). The performance information is stored locally or in the “cloud” for easy access, available from any web browser on a computer or smart phone.

“We want consumers to be able buy these kinds of devices and appliances inexpensively and then use them with any demand response service providers,” Ghatikar said. “Let’s say a homeowner buys a smart thermostat or appliances in the Bay Area and then wants to move to Southern California. They will want to take their thermostat or the appliances with them and for them to be able to communicate with and respond to the demand response signals from another utility as well,” he said.

Moving Forward: Integration with the FLEXLAB

First-year operations of the D2G Lab have effectively demonstrated the goal research areas, identified new areas of research and development, and validated findings and conclusions that benefit the wider demand response community. In addition to continuing existing demonstrations, the D2G Lab’s second-year goals include conducting new demonstrations that provide a suitable grid integration research and demonstration framework for Berkeley Lab’s new FLEXLAB—a research facility opening later in 2013 to study energy efficiency technologies in buildings.

FLEXLAB provides a set of tools to allow research in how buildings components and systems can be designed and controlled to support the U.S. Department of Energy’s (DOE’s) Energy Efficiency and Renewable Energy Grid Integration initiatives. Improving the flexibility of electric loads in buildings will allow the electric grid to be more cost effective as more intermittent renewables are used in the supply systems.

D2G Lab Demonstrations at the FLEXLAB

More About FLEXLAB

The FLEXLAB, or the Facility for Low Energy Experiments in Buildings, offers researchers a unique opportunity to collaborate in development, simulation, and validation of efficient building technologies. FLEXLAB will provide structures for manufacturers to conduct focused research and product development on single components or whole-building integrated systems. Building industry researchers can investigate building envelopes, windows and shading systems, lights, HVAC, energy control systems, roofs and skylights, or interior?components such as furniture, partitions, and raised floors. The building loads can be controlled with electric batteries or integrated with Electric Vehicle chargers. The FLEXLAB will expand the DRRC’s demand response research.

—by Kyra Epstein

More about the Demand to Grid Lab here.

The D2G Lab Team:

Rish Ghatikar, Deputy Leader, Grid Integration Group and Project Lead

Janie Page and Chuck McParland, Lead for the Appliances and the HAN

Sila Kiliccote and Vish Ganti, Lead for the V2G

Vish Ganti, Project Coordinator, Technologies Demonstration and Analysis

Public and private financing is available, but navigating the complicated landscape of grants, bonds, leasing arrangements and other types of financing can be difficult for school administrators and facilities managers, who are not necessarily experts in financing for energy efficiency and renewables.

Researchers Merrian Borgeson and Mark Zimring, in Berkeley Lab’s Environmental Energy Technologies Division (EETD), have released a guide on planning and financing comprehensive energy upgrades that involve multiple measures and are targeted toward achieving significant and persistent energy savings.

Written for school district administrators

The guide is written explicitly for school administrators, facilities managers, and others in K-12 education management. It covers different options for public and private financing approaches, and contains numerous case studies of school district projects. The authors provide explanations of financial terms and mechanisms.

“The money spent on energy for schools is their second-highest operating expenditure after personnel costs—more money than is spent on textbooks and computers combined,” says Borgeson. “Comprehensive energy efficiency upgrades for schools bring them a lot of benefits—the biggest might be that lower energy bills allow them to spend more money on hiring teachers and buying supplies.”

Another significant benefit is that energy efficiency upgrades result in modernized infrastructure and lower maintenance costs—for example, through improved heating and cooling systems, energy-efficient windows and roofs, and better ventilation.

These energy upgrades also improve the comfort, health and safety of school buildings. Fixing the hot and cold spots, leaky walls and roofs, and broken windows not only reduces energy costs, it improves the indoor environmental quality of the building, and enhances the ability of students to learn and teachers to teach. Chosen carefully, energy-efficient equipment, for example, can be quieter, and do a better job at removing indoor pollutants that can affect human cognitive ability. Removing mold and toxic materials provides a safer learning environment.

Case studies provide guidance to overcoming obstacles

Six case studies drawn from the experience of school districts around the U.S. tell the stories of how district policymakers overcame obstacles, built consensus, and chose funding mechanisms for energy efficiency upgrades that were widely accepted by their districts’ stakeholders—parents, taxpayers, political leadership.

Williamson County School District in Tennessee, for example, entered into an energy savings performance contract (ESPC) with an energy services company (ESCO) and completed a $5.7 million lease-purchase agreement to fund a range of energy-related improvements across 27 school facilities.

The lease-purchase agreement helped reduce the barrier of up-front costs of the upgrades, and re-financing a year later benefitted both the district and taxpayers. The project will pay for itself in six and a half years, and continue saving money for the district long after that time.

Douglas County School District, Nevada, used a combination of financial mechanisms to fund $10.7 million in upgrades.  They tapped into federal Qualified School Construction Bonds, an American Recovery and Reinvestment Act grant, and voter-approved General Obligation bonds to fund a range of equipment and facility improvements.

“Most schools already have access to many of the financing tools they need to invest in these improvements,” says Borgeson, “We think that every school has the potential to become a high performance school, one that has an improved student learning environment, and saves energy, resources, and money. They just need to understand what the opportunities are, and tap into those opportunities.”

“Financing Energy Upgrades for K-12 School Districts,” by Merrian Borgeson and Mark Zimring, is available for free download here. The work was funded by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy, and the American Recovery and Reinvestment Act.

Join the conversation at hes.lbl.gov/community.

The new online forum is part of the Berkeley Lab’s popular Home Energy Saver interactive home energy assessment tool. According to Berkeley Lab’s Evan Mills, “the Home Energy Saver Community harnesses the popularity of social media, both to motivate homeowners to engage more in the process of remodeling their homes, and to help them be more comfortable and energy efficient.”

The Home Energy Saver Community, which launched on March 19, 2013, features rich content from the forthcoming guidebook, No-Regrets Remodeling, 2nd Edition, as well as case studies, energy-expert blogs, videos, a Google calendar that provides energy-saving to-dos that users can even import into their own calendars, and more. Hard copy and electronic versions of the book will be published by Home Energy magazine later this spring. The book highlights steps where readers can use the do-it-yourself Home Energy Saver online energy assessment tool to obtain a list of energy-saving upgrades tailored to their home, climate, and local energy prices.

Read the rest of this blog entry from Home Energy magazine at the link below.

The keynote presenters are Assistant Secretary Patricia Hoffman of the U.S. Department of Energy’s Office of Electricity Delivery and Energy Reliability, and Assemblymember Nancy Skinner (15th District). The agenda will include updates on energy storage at the state and federal levels, as well as a deep dive into some local energy storage initiatives.

Thursday, April 11, 2013
8:00 am to 4:00 pm
Microsoft Auditorium
1065 La Avenida Street,
Mountain View, California

Register:

http://www.jointventure.org/index.php?option=com_content&view=article&id=871&Itemid=436

The competition is in its second year, and is managed by Lawrence Berkeley National Laboratory’s (Berkeley Lab’s) Energy Efficiency Standards Group with support from the U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy, Emerging Technology Program. The chosen teams receive up to $20,000 to implement their proposals over the course of the 2012/2013 academic year.

A panel of Berkeley Lab and DOE sector experts selected eight teams following a solicitation at more than 90 universities. The eight teams are from the University of Maryland, Cal Poly Pomona, Tufts, Ohio State, Santa Clara University, the University of Nevada, Stony Brook University, and the University of California, Berkeley. The teams, consisting of undergraduate or graduate students, or a combination of both, are prototyping an ultra-efficient hybrid air conditioning and water heating system, a thermosiphon-based refrigerator, and automated space-conditioning window shades, among other devices. The student teams have completed their design and procurement phase and are working on adapting and applying their technologies, building prototypes. They will be entering into the testing phase soon.

The competition culminates in a national webinar on May 23, 2013, in which the student teams will demonstrate their prototypes. The event is open to the public. The achievements of all of the teams will be reported on the Max TechDesign Competition website, with the winners announced in August 2013.

The winner of the 2011-2012 competition, a team from the University of Maryland, devised a way to improve the efficiency of an air conditioning system substantially by separating latent and sensible cooling, using a desiccant wheel to provide the latent cooling. Compared with best-on-market wall-mounted air conditioners, tests of the prototype in a climate chamber showed a reduction in energy use by 30%. The runner-up team, from Marquette University, developed a hybrid gas-powered clothes dryer and water heater. Their hybrid system only needs one modulating burner that can be shared between the two appliances, cutting the overall appliance energy use by more than 20%.

Dr. Yunho Hwang, from the University of Maryland, and lead Faculty Advisor for the winning team last year, says:

“Max Tech and Beyond Competition opened the opportunity for engineering students to draw their imaginations and visualize their ideas. I was asked by many of the engineering students, ‘When is the next Max Tech And Beyond Competition to be held?’ I am very excited that we are returning to Max Tech and Beyond Competition for the second year because it provides such a core engineering educational opportunity to our students.”

Berkeley Labs Dr. Robert Van Buskirk, one of the original initiators of the Competition, had this to add:

“The Department of Energy recognizes that innovation in energy efficiency technologies will play a very large role in mitigating climate change over the long term. The Max Tech competition helps harness the creativity of the nation’s young scientists and engineers to help meet this very important global challenge. A year of effort by a dedicated team of students today has the potential of seeding those new technologies and devices that could save the country and the world billions of dollars in energy and climate change costs during the coming decades.”

Contact Information

Those interested in obtaining more information about the competition or in helping to sponsor the competition in the future should refer to the website and call (510) 495-2100 or e-mail the program organizers at maxtech@dante.lbl.gov.

Against this backdrop, Lawrence Berkeley National Laboratory (Berkeley Lab) today released a new report, funded by the U.S. Department of Energy, that investigates the degree to which wind power can still serve as a cost-effective hedge against rising natural gas prices, given the significant reduction in gas prices in recent years, coupled with expectations that gas prices will remain low for many years to come.

Drawing on a sizable sample of long-term power purchase agreements (“PPAs”) between existing wind projects and utilities in the U.S., the report compares wind power prices that have been contractually locked in for decades to come with a range of long-term natural gas price projections. It finds that–even within today’s low gas price environment–wind power can still provide a cost-effective long-term hedge against many of the higher-priced future natural gas scenarios being contemplated. This finding is particularly evident among the more-recent contracts in the PPA sample, whose power sales prices better reflect recent improvements in the cost and performance of wind power.

With shale gas likely to keep a lid on domestic natural gas prices in the near-term, the report’s focus is decidedly long-term in nature.  “Short-term gas price risk can already be effectively hedged using conventional hedging instruments like futures, options, and bilateral physical supply contracts, but these instruments come up short when one tries to lock in prices over longer durations,” notes report author and scientist Mark Bolinger of Berkeley Lab’s Environmental Energy Technologies Division.  “It is over these longer durations where inherently stable-priced generation sources like wind power hold a rather unique competitive advantage.”

A copy of the report, titled “Revisiting the Long-Term Hedge Value of Wind Power in An Era of Low Natural Gas Prices,” along with a slide deck summarizing the work, can be downloaded from the following web site:

http://emp.lbl.gov/publications/revisiting-long-term-hedge-value-wind-power-era-low-natural-gas-prices

In addition, Berkeley Lab will host a webinar on Thursday, March 14 from 1-2 PM EDT to present the research and answer questions.  Pre-registration is required, via the following link:

https://cc.readytalk.com/r/ury5a947vzx7

Apte is also a PhD candidate in the Energy and Resources Group at the University of California, Berkeley. He conducts research on the environmental and health impacts of energy, transportation and other urban infrastructure systems. His dissertation employs mathematical models and field measurements to characterize human exposure to motor vehicle air pollution, emphasizing conditions in developing countries.

The award was announced in a ceremony attended by a group that included Scientist Emeritus Art Rosenfeld, Lab Director Paul Alivisatos, Deputy Director Horst Simon, Environmental Energy Technologies Division Director Ashok Gadgil, Deputy Division Director Robert Kostecki, and a delegation from the Industrial Technology Research Institute of Taiwan (ITRI) including: Dr. Hsin-Shen Chu (Former Executive Vice President, ITRI), Dr. Wu-Chi Ho (Deputy General Director of Green Energy Labs, GEL), Dr. Chia-Ming Liu (Manager of Planning Division, GEL), Dr. Shoung Ouyang (Technical Director of Resource Division of GEL), Dr. Ren-Chain (Joseph) Wang (Deputy Director of Planning Division, ITRI), and Dr. Shao-Hwa (Sean) Wang (President, ITRI International).

The ITRI-Rosenfeld Fellowship will allow its winner to engage in innovative research leading to new energy efficiency technologies or policies and reduction of adverse energy-related environmental impacts.

Since was announced in August 2012, the committee received 17 outstanding applications for the fellowship. Over several months, a rigorous selection process began with scrutiny of the applications by a high-level Scientific Selection Committee to select the top three finalists, followed by presentations by the finalists and finally interviews to select the winner.

The fellowship has been provided with support from ITRI.  It honors the contributions of Arthur H. Rosenfeld, Ph.D., fondly known as the Father of Energy Efficiency for his work towards the advancement of energy efficiency on a global scale. In the 1970s, Dr. Rosenfeld pioneered energy efficiency technology research at what would become the Berkeley Lab’s Environmental Energy Technologies Division.

ITRI-Rosenfeld Fellowship website:

http://eetd.lbl.gov/about-us/itri-rosenfeld-postdoctoral-fellowship

Joshua Apte’s website:

http://www.ocf.berkeley.edu/~apte/index.html

Art Rosenfeld:

https://sites.google.com/a/lbl.gov/cool-white-planet/

Using EnergyPlus—the U.S. Department of Energy’s software that simulates energy use in buildings—designers can determine the most energy-efficient use of technologies and designs for the building. Other simulation and modeling platforms and languages accomplish other tasks; for example, the Modelica language can be used to simulate complex engineered systems (such as mechanical, electrical, and control systems), and the MATLAB and Simulink simulation tools can be used for scientific computing (creating algorithms to automate decision making and analyze data to find better ways to design and operate engineered systems).

In 2008, Lawrence Berkeley National Laboratory (Berkeley Lab) developed the Building Controls Virtual Test Bed (BCVTB), which enables these various simulation environments to “talk” to each other. The BCVTB is a software environment that allows expert users to couple simulation programs together virtually, and to couple simulation programs with actual hardware. Based on the Ptolemy II software environment (an open-source modeling and design software developed by the University of California at Berkeley), the BCVTB allows users to expand the capabilities of individual programs by linking them to other programs.

“The BCVTB allows users to test building control systems before they are installed in an actual building,” said Michael Wetter, a BCVTB developer in Berkeley Lab’s Simulation Research Group. “For example, the BCVTB allows users to simulate a building in EnergyPlus and the HVAC and control system in Modelica, while exchanging data between the software programs as they simulate,” he said.

Advanced Co-Simulation

This ability to “co-simulate” gives designers the ability to use models that best accomplish the task needed for each function, rather than trying to modify one model to make it do something it was not specifically designed to do.

According to Wetter, the impetus to develop the BCVTB was to address some of these deficiencies that emerged as researchers and designers used models in more complex and innovative ways. For example, building simulation programs were not designed for multi-disciplinary analysis, and tools were unable to properly analyze innovative systems, control sequences, and equipment not yet included in software packages. When models or tools were not available, designers had to develop them themselves or to rely on expensive and time-intensive full-scale experiments.

The BCVTB overcomes these deficiencies with its co-simulation ability for a variety of software programs:

• The EnergyPlus whole-building energy simulation program
• The Modelica modeling and simulation environment Dymola
• The MATLAB and Simulink tools for scientific computing
• The Radiance ray-tracing software for lighting analysis
• The ESP-r integrated building energy modeling program
• The BACnet stack, which allows data exchange with BACnet-compliant Building Automation Systems (BAS)
• The analog/digital interface USB-1208LS from Measurement Computing Corporation that can be connected to a USB port

Other programs can be used and combined in the BCVTB environment as well.

Typical applications of the BCVTB include:

• Performance assessment of integrated building energy and control systems
• Development of new control algorithms
• Formal verification of control algorithms prior to their installation in a building—to reduce commissioning time

For example, by combining Modelica with EnergyPlus through the BCVTB, users can model the building heat flow and daylight availability and use Modelica to model innovative building energy and control systems using its “Buildings” library (http://simulationresearch.lbl.gov/modelica). This allows even more advanced uses of the BCVTB:

• Define on-the-fly new HVAC components and systems in a modular, hierarchical, object-oriented, equation-based graphical modeling environment and couple them to EnergyPlus
• Innovate new HVAC system and control architectures for which models do not yet exist in off-the-shelf building simulation programs
• Analyze dynamic effects of HVAC systems, modeled in Modelica, and their local and supervisory control loops, modeled in MATLAB/Simulink, Modelica, or Ptolemy II
• Simulate virtual experiments prior to full-scale testing in a laboratory or a real building to determine the range of required boundary conditions, the type of experiments that need to be conducted and, for example, to improve a control logic in simulation where iterations can be made faster than in an actual experiment

Real-Time Data Inputs

In addition to coupling software programs together, the BCVTB can also be used as an interface between the simulated building and the actual sensors in the physical building. This approach allows real-time data to pass from the sensors into the simulated environment and be analyzed against best-case design scenarios. It can be used in a variety of applications, including research to improve equipment and controls, as well as in commissioning buildings once constructed and in operation.

Yao-Jung Wen, senior researcher at Philips Research North America, was one of the first BCVTB users.

“Philips is interested in lighting—what lighting controls can do for energy efficiency and how they interact with other building systems such as blinds or shades, heating or air conditioning,” Wen said. “When we started working with the BCVTB, we wondered, ‘What if we take EnergyPlus out, and plug in a real building?’”

In this scenario, sensors gave Wen’s team actual light levels, which went to the BCVTB interface and were translated into the format that BCVTB recognizes. Then the data were sent to the control algorithm in MATLAB, back to the interface, and then back to the building—moving the blind or shade, for example.

“We used the BCVTB to create a separation between the controls and the physical systems so that the controller could easily be implemented, tested, and tuned with real performance feedback from a physical implementation,” he said.

In another example, the research group at Johnson Controls is working with two universities who are using the BCVTB to couple simulation programs to test the way buildings and HVAC equipment are controlled—with a goal of improving energy efficiency while maintaining comfort.

With McMaster University in Ontario, they are developing and testing a new way to control an air conditioning unit using an advanced control strategy.

“McMaster is coupling an EnergyPlus model of the building with a Modelica model of the HVAC equipment, and is using MATLAB for optimization,” said John House, a principal research engineer with Johnson Controls who is involved with the project. “The BCVTB has been directing the data flow between these various platforms.”

On another project, Johnson Controls worked with the University of Southern California to study how to control building temperatures to minimize the cost of cooling a building.

“Specifically, they were trying to shift cooling loads from the afternoon when electricity was relatively expensive to early morning before occupancy, when the electricity rates were lower. The BCVTB was used to couple an EnergyPlus building model with optimization routines in MATLAB,” House said. The team demonstrated the capability of the control algorithm to shift cooling loads in a Johnson Controls building in Milwaukee, Wisconsin.

“The BCVTB makes us much more efficient—it allows us to use the simulation tools that are best for a particular task,” House said.

—Kyra Epstein

For more information, visit  http://simulationresearch.lbl.gov/bcvtb

or contact Michael Wetter at MWetter@lbl.gov

This research was funded by the Department of Energy’s Office of Energy Efficiency and Renewable Energy.

Worldwide Collaboration on Modelica

In June, the International Energy Agency—under the implementing agreement on Energy Conservation in Buildings and Community Systems—approved a five-year project called “Annex 60: New generation computational tools for building and community energy systems based on the Modelica and Functional Mockup Interface standards.” In this project, led by Michael Wetter from Berkeley Lab and Christoph van Treeck from RWTH Aachen University in Germany, 30 institutes from 9 countries will share, further develop, and deploy free, open-source next-generation software for building and community energy systems.

The project will create and validate standardized tool chains that link building information models to energy modeling; building simulation to control design tools; and design tools to operational tools. By extending, unifying, and documenting existing Modelica libraries, the team aims to accelerate innovation and use of integrated energy-related systems and performance-based solutions for buildings and communities. Using the Functional Mockup Interface standard—a standard for co-simulation and for sharing models—users can link existing building performance simulation programs with such libraries and other tools.

The technology will allow for better design, analysis, and operation of multi-domain systems in building and community energy systems. It will also allow modeling across the whole-building life cycle to ensure that the design intent is realized and sustained.

—Kyra Epstein

The U.S. Department of Energy’s (DOE’s) open-source EnergyPlus building energy simulation program has helped architects and engineers design more efficient buildings for more than a decade. However, it can take a great deal of effort to input information and analyze the output. As a result, many have avoided using the program, while others have turned to third-party graphical user interfaces (GUIs) to increase its effectiveness. As entities such as the California Energy Commission, Hydro Québec, and Trane switch from DOE-2 to EnergyPlus, it is more important than ever to combine an easy-to-use GUI with the powerful capabilities of EnergyPlus.

Easier Access to EnergyPlus

To address the need for a more flexible, usable interface, the Simulation Research Group at Lawrence Berkeley National Laboratory (Berkeley Lab) worked with a public/private team to develop Simergy—a new GUI for EnergyPlus. Specifically designed for practitioners, the new, free GUI enables users to access the benefits of EnergyPlus much more easily. The beta version was released in October 2012 and is undergoing testing.

“The focus was on the end-user from the start of the project,” says the Environmental Energy Technologies Division’s (EETD) Philip Haves. “Berkeley Lab initiated and participated in a series of workshops where practitioners helped to define features that would enable them to use EnergyPlus effectively. We used their recommendations to develop a product that would meet their specific needs.”

Evolving Simergy Development Will Continue to Broaden Usability

Version 1 of Simergy will address design for new construction and is slated to be released in the first quarter of 2013. It will incorporate feedback from several months of beta testing, and users will benefit from the following key features:

• Capability to manage and evaluate design alternatives.
• Ability to translate building envelope geometry from CAD or Building Information Models (BIM) to Building Energy Models (BEM). Workflows are based on the industry standard protocols IFC-Design Concept BIM and gbXML, or they can be generated by Simergy. The CAD input is an improvement over previous GUIs, especially when using IFC.
• Extensive sets of libraries and templates for construction materials, schedules and HVAC equipment, and systems for both conventional and low-energy systems.
• Drag-and-drop component-based HVAC schematic editing.
• Summary reports that can be customized to the user’s desired level of detail.
• Interactive detailed results visualization.

Future developments are planned to include:

• Support for early-stage integrated design.
• Automated code compliance.
• For existing buildings, an integrated approach to semi-automated retro-commissioning, retrofit analysis, retrofit commissioning, and performance tracking for fault detection.
• Support for enhanced daylight modeling using a computationally efficient version of Radiance linked to EnergyPlus.

Using real-time EnergyPlus connected to a building control system, Version 2 of Simergy will be able to provide whole-building performance monitoring and fault detection. This capability will enable users to compare simulation and measurement for whole-building electric and gas, lighting, plug loads, and major HVAC components, to help maintain persistence of energy savings.

In addition, a professional version based on the free GUI is planned by one of the team’s private-sector partners.

Simergy development is conducted by a public/private partnership led by Berkeley Lab and including Digital Alchemy, Hydro-Québec, Infosys Technologies, and Trane, with input on user requirements and template design from Arup, HOK, SOM, and Taylor Engineering. It has been funded by the California Energy Commission, DOE, Hydro-Québec, Infosys, the Northwest Energy Efficiency Alliance, and Trane.

More information can be found at the Berkeley Lab Simulation Research Group’s Simergy website: http://simulationresearch.lbl.gov/projects/gui and the software can be downloaded at http://simergy-beta.lbl.gov/.

—Mark Wilson

For further information, contact Philip Haves at PHaves@lbl.gov, (510) 486-6512.