Fraunhofer CSE’s Building America Research Now Available

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For the past fifteen years, the U.S. Department of Energy’s Building America program has drawn on researchers, industry, and the US national lab system to develop and demonstrate market-ready solutions for builders and homeowners that improve durability, comfort, and energy efficiency.

In the summer of 2010, a Fraunhofer CSE-led research team was selected to investigate technologies and methods that could dramatically increase both the scale and depth of home energy efficiency retrofits in the United States. This cross-disciplinary team drew on 33 partners from across the building value chain, ranging from materials and systems manufacturers like Owens Corning and Mitsubishi Electric to builders, developers, and architects, research institutions, and municipal governments.

Over the next two years, members of the CSE Building Energy Technology teams proposed and pursued a variety of research projects that leveraged CSE’s strengths in building science, energy modeling, field testing, and experimental psychology, coupling laboratory testing at our Cambridge facility with deployments and field evaluations in Massachusetts, Texas, and Maine. The results of four of these projects have recently become available as Final Reports to NREL and the Department of Energy.

CSE’s Building America projects include laboratory work as well as field testing carried out in several US states.

CSE’s Building America projects include laboratory work as well as field testing carried out in several US states.

Cold Climate Building Enclosure Solutions

Spearheaded by CSE’s Building Enclosures team, one project looked at emerging insulation solutions for buildings in cold climates, with a particular focus on Boston and the greater New England area. Over the course of several months, the team evaluated a number of novel, high-performance insulation options, including vacuum insulation panels and aerogel, two insulation materials gaining in prominence due to their high thermal resistance properties. The cost of these insulation types has dropped in recent years, making them an increasingly viable option for builders and homeowners, although true mass-market penetration is still to come.

Based on their findings, the CSE team proposed developing a new and highly effective type of thermal insulation option for cold-climate homes – blown-cavity insulation using aerogel material. While this concept is not yet market-ready, blown-in aerogels have the potential to be a major cost-saver for niche areas of building insulation.

Shredded aerogels like these could provide effective insulation in cold climate homes.

Shredded aerogels like these could provide effective insulation in cold climate homes.

Field Evaluation of Programmable Thermostats

While energy-efficient technology plays an important role in reducing consumption, occupant behavior is also critical. In this study, a team of CSE psychologists and engineers collaborated to explore the ways that people interact with programmable thermostats, and how best to involve end users in the process of managing the energy used to heat and cool their homes. To this end, CSE researchers deployed easy-to-use and basic programmable thermostats in Massachusetts households and monitored occupant behavior over a three-month period to see if people with easy-to-use thermostats were more likely to use their energy-saving features, such as nighttime setbacks.

Thermostat usability turned out to have no impact on how thermostats were used to save energy, as few households continued to use the energy-saving schedules that came pre-installed on all thermostats. Instead, the majority of households that participated in the study manually overrode the schedules. Thermal comfort, not energy efficiency, appeared to be the major motivating factor for how residents interacted with the equipment. This finding suggests that unless people are motivated to save energy, building owners and managers who replace basic thermostats with costlier, design-heavy models will see only a minimal decrease in energy consumption.

To evaluate thermostat usage, CSE collected data from 77 apartments in Massachusetts.

To evaluate thermostat usage, CSE collected data from 77 apartments in Massachusetts.

Home Energy Displays: Consumer Adoption and Response

The Energy Management team also evaluated home energy displays (HEDs) – devices that provide information on whole-home electricity consumption to energy-conscious users. While existing research suggests that HEDs can reduce consumption by 4% to 13%, these savings may not persist as users become less engaged with the devices over time. The main focus of CSE’s research was to investigate the factors that influenced consumer adoption of HEDs, and to evaluate how much of an impact different kinds of HEDs and consumption feedback methods actually had on energy consumption in households.

In a series of focus groups designed to address barriers to HED adoption, the CSE team found that respondents primarily valued flexibility, clarity, and cost when weighing whether to purchase such devices. After an initial round of field deployment studies, CSE is currently engaged in a follow-on project at Harvard University that investigates alternate methods of delivering energy consumption feedback to consumers.

An installation in progress at one of Fraunhofer CSE’s field deployment sites.

An installation in progress at one of Fraunhofer CSE’s field deployment sites.

 

Comfort, Indoor Air Quality, and Energy Consumption in Low Energy Homes

In 2010, Fraunhofer CSE began monitoring several Massachusetts residences that had been designed to be net zero energy homes (NZEHs). The NZEH concept combines high-quality insulation, energy-efficient appliances and systems, and energy generation technologies such as solar panels to create a building that produces as much energy as it consumes. The main objective of CSE’s research was to determine whether claims about the energy efficiency, comfort, and health benefits of the various energy-saving and -producing measures used in these buildings were supported by measured field data.

To achieve this, CSE researchers set up an ongoing monitoring effort, using a range of sensors to evaluate indoor comfort, temperature, humidity, carbon dioxide levels, and electricity consumption at the circuit level over the course of more than one year. Shorter-term evaluations of a wide range of indoor pollutants were also carried out.

NZEHs are an extreme example of what can be achieved in energy-efficient building. However, the technologies and design concepts have direct relevance in a number of different residential applications, and could lead to innovations that become commonplace features in today’s homes.

Zero net energy buildings generate power through technologies like solar panels in order to offset what is consumed in the building.

Zero net energy buildings generate power through technologies like solar panels in order to offset what is consumed in the building.

Other Projects

Beyond these four projects, CSE’s teams pursued several other Building America-related research efforts, which included:

  • Carrying out field testing of high-performance windows
  • Assessing retrofit strategies that offer thermal radiation control for roofs and attics in cooling-dominated US climates
  • Evaluating the comfort provided by ductless mini-split heat pumps
  • Measuring the dynamic thermal characteristics of building enclosure components that contain phase change materials (PCMs)

Fraunhofer CSE will make these full project reports available as they are released.

The CSE Building Energy Technology team continues to investigate energy-efficient retrofit technologies through laboratory testing and field deployments, including partnering with CSE’s TechBridge incubation team on a pilot project to assess the effectiveness of radiator enclosures.

 [Additional material by Martin Sachs]

 

 

About author
I'm a freelance writer, journalist, and former Marketing Associate at Fraunhofer CSE. My work has appeared in the Chicago Tribune, Knowledge@Wharton, Recessionwire, and Data Informed.
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