Case Study on Team WashU’s Solar Decathlon Home: It’s All About Concrete for Sustainability and Comfort

08/09/2021 at 2:19 pm by Blomberg

CRETE house – Washington University in St. Louis’s first-ever entry in the U.S. Department of Energy Solar Decathlon – is like no other. First of all, it’s constructed of concrete, not wood or steel. And it eschews a traditional HVAC system, instead using water coils embedded within the panels to warm or cool the home. Over the last two years, the WashU Solar Decathlon team of more than 100 undergraduate and graduate students have created the single pre-cast concrete structure as a demonstration of integrated advanced building technology and a compelling alternative to traditional wood, light-frame construction. “With our CRETE house, we hope to show how prefabricated, self-sustaining and resilient homes can mitigate climate change,” said Ryan Abendroth, faculty project manager for Team WashU’s Solar Decathlon home, and a Senior Lecturer in architecture. Contributing to the energy efficiency of the home are Euro-design, ENERGY STAR®-certified appliances by Blomberg (www.blombergappliances.com), a rapidly growing major appliance brand for builders, designers and architects of multi-unit buildings in urban America. Solar Decathlon ChallengeThe Solar Decathlon challenges the 12 participating university teams to design and build full-sized solar-powered houses, which are then disassembled, shipped to Denver, Colo., and reassembled for judging and exhibition to the public on Oct. 5-9, and 12-15, 2017. The winner is the team that best blends design excellence and smart energy production with innovation, market potential, and energy and water efficiency. Washington University will receive prize money of $100,000 for its participation, and the overall winner will receive $300,000. Team WashU’s 995-square-foot home will be the first in an eco-village of net zero-energy-ready buildings being planned at the Tyson Research Center, an internationally renowned biological field station sited on 2000 acres of native landscape in Eureka, Missouri. CRETE house will become the long-term residence for two research scientists. In addition to the research and development that has been put into the house during the design, construction and operation phases, the structure will be used as a test bed for further research and education. Why Concrete?High performance precast concrete is inherently resilient, protecting against fire, moisture and mold, insects, seismic events and extreme weather conditions such as storms and strong winds. Although the manufacturing process emits carbon dioxide, those emissions are offset by the material’s longevity and unique thermal properties. Concrete boasts a high heat capacity, or thermal mass. On a summer afternoon, concrete walls absorb the warmth of the sun, slowing the rise of interior temperatures. On a summer evening, natural ventilation releases the heat back outside, dispersing it into the cool night air. “Aesthetically, the home showcases precast pieces and a wide variety of concrete materials and finishes in textures and patterns never seen before,” says Abendroth. “For example, the polished floor is a smooth gray color with a hint of tan, while the interior walls are machine-trowelled with a dark gray swirl, the outdoor walls are off-white, the kitchen countertop is polished with an exposed aggregate, the exterior furniture is white GFRC and Lamboo, and the ceiling is standard structural concrete with a form finish.” Design ProcessIn the fall of 2015, in the first of four semester-long studios offered at Washington University as part of the Solar Decathlon project, students investigated sustainable strategies for heating, cooling and ventilation, looking for ways to reduce and/or offset energy consumption, while still maintaining a comfortable, functional space. They created individual proposals, which were eventually merged into the final design. The team includes students from the architecture, landscape architecture, engineering, computer science, construction management and public health programs. This summer, they are focused on constructing the home on WashU’s north campus, with the help of professional builders. In September, the team will pack up CRETE house and ship it to Denver for the competition. Key features of the two-bedroom, one-bathroom home include: Open kitchen and living room area Energy-efficient kitchen and laundry appliances from Blomberg Six insulated precast concrete wall panels, plus five roof and floor panels, that are factory-produced and assembled on-site Use of Ductal (UHPC, Ultra High Performance Concrete), which provides six times the compressive strength than standard precast concrete. The extra strength allows a reduction in thickness and therefore a reduction in weight of the overall panel Radiant heating in floors and cooling in ceiling tied to geothermal heat pump system Specially designed dry connection methods using bolts rather than traditional field welds make field assembly much easier than traditional methods, significantly reducing labor and material waste Oversized gutters that extend out from the main concrete structure for water harvesting, while creating outdoor living space A water collection system and series of modular planters that allow hydroponic gardening as part of a productive landscape with cultivation of vegetables for consumption The $420,000 cost of building the home was offset by university contributions, external fundraising, in-kind donations and support from concrete companies and other industry partners. “When we started looking at appliances, we realized that Blomberg’s ventless heat pump dryer was the next big thing in energy efficiency, and that their appliances were among the most efficient,” Abendroth said. “When we saw they were sponsoring the Solar Decathlon, we reached out to the company. They donated four modern, energy-efficient appliances, including an induction cooktop brand new to the market.” Other appliances chosen for the CRETE house included: Built-In Wall Oven (BWOS30100) – 30” wide convection electric wall oven; 3D cooking function; eight built-in functions and a programmable digital timer; pyrolytic self-cleaning function Dishwasher (DWS55100FBI) – 18” ADA compatible, fully integrated dishwasher with 49dBA Silent Operation; brushless DC™ motor with variable speed that allows optimum amount of water and energy Stackable Compact Washer (WMY98400SX) and Dryer (DHP24412W) – large capacity with 2.5 cu. ft. washing capacity and 4.1 cu. ft. drying capacity; 24” front-loading Washer with 1,400 RPM maximum spin speed and 16 washing programs; 24” Ventless Heat Pump Dryer with 16 drying programs; chrome door rim; white Blomberg’s innovative heat pump dryer made the Environmental Protection Agency’s (EPA’s) 2017 ENERGY STAR Most Efficient list for using 50 percent less energy than conventional dryers. Blomberg was among the first to bring the ventless heat pump technology to the marketplace. The heat pump dryer uses a closed-loop heat exchange system to dry at lower temperatures, saving money on energy bills and providing superior protection for clothes. In addition, several Blomberg dishwashers made this year’s ENERGY STAR® Most Efficient list, and all models have earned ENERGY STAR marks for using advanced technology to clean dishes brilliantly with less water and energy. Unique design features include multiple insulation layers to reduce thermal loss, and a variable speed circulation motor that automatically adjusts for optimum water and energy consumption. Blomberg’s ENERGY STAR certified refrigerators also save energy and money and conserve the planet. They are built with 99.9 percent lead-free materials, are 100 percent free from ozone-depleting greenhouse gases, and are manufactured with 85 percent recyclable components. In fact, the company has achieved the ENERGY STAR certification for over 90% of the major appliances. According to the EPA, appliances with the ENERGY STAR label can help a consumer save $630 over a product’s lifetime. With its sponsorship of the U.S. Department of Energy Solar Decathlon 2017, Blomberg is going the distance to help accelerate the adoption of energy-efficient products and design in American homes. Blomberg is part of Beko US, Inc., which was founded in June 2016 and opened a distribution center in Bolingbrook, Ill. Beko US, Inc. recently received the Environmental Protection Agency’s 2017 ENERGY STAR® Partner of the Year Award. The award recognizes the company’s outstanding contributions to protecting the environment through energy efficiency. “Everything we do is centered around sustainability and innovation,” said Hasan Yardimci, president, Beko US, Inc. “Our support of the Solar Decathlon is in keeping with our commitment to provide consumers with products that are both good for the globe and support their everyday needs.” # # # About BlombergEstablished in 1883 in Germany, Blomberg has delivered quality and innovation in the appliance and metal industries for more than 130 years. Arçelik A.Ş., the third largest appliance manufacturer in Europe, acquired Blomberg in 2002. As a widely valued international name, Blomberg has established itself in North America since 2008 with an ever-expanding line of contemporary European design and energy efficient products for builders, designers and architects of multi-unit buildings. The company utilizes the most advanced technology and features, and the highest quality materials to achieve cutting-edge performance found in larger footprint homes, but optimized for smaller urban living spaces. For more information, visit http://www.blombergappliances.com.