Regarding the continuation of our built environment, lately climate change has been an important and concrete issue that needs to be addressed in every aspects of our daily life. Irresponsible natural resources exploitation has lead us to the excessive production of greenhouse gases emitted by human activity, inducing anthropogenic climate change (Global Greenhouse Warming). As the real consequences, we now frequently face global warming, the rising mean sea level, extreme weather, unpredictable rainfall, storm surges, and so on. The fifth assessment report (AR5) of IPCC (United Nations Intergovernmental Panel on Climate Change) has vocally pointed out that warming of the atmosphere and ocean system is unequivocal. Climate change has been happening irreversibly, where no sustainable effort done has shown any significant performance against it.
The IPCC report also makes the point that the longer we wait to reduce our emissions, the more expensive it will become.
The bottom line is that economists can’t even accurately estimate how much climate damages will cost if we fail to take serious steps to slow global warming. It’s important to understand that our choices aren’t to either reduce carbon emissions or to do nothing. Our options are to either reduce carbon emissions or to continue with business-as-usual emissions that will cause accelerating climate change and damage costs beyond what we can accurately estimate. (Nuccitelli, 2014, for The Guardian).
Stopping climate change is probably nearly impossible at the current moment, considering it requires a global effort to stop emission. While we know, to coordinate such thing with a top-down approach will require so many complicated processes and to shift the old paradigm will encounter long term socio-economic and political obstacles and expensive technology. Nevertheless, it is not possible to mitigate the climate change impacts, if we find a more feasible and doable efforts with top-down approach.
Urban planning and design is one of the fields that can turn our built environment into a new ecological unit that is adaptive to climate change, while mitigating the anthropogenic-induced climate change at the same time. Building a more sustainable and energy efficient housing unit would be the most strategic subject that should become a main focus in mitigating climate change on a global scale. Modern cities and human beings are the interrelated responsible keys, where many human settlements do not function sustainably. That includes houses or housing settlements, in which people spend most of their daily life besides commercial and working zones.
Since 2002, Solar Decathlon from US Department of Energy has been supporting universities and research centers focusing on sustainability and energy efficiency to remodel a new house model for the future in a form of biennale competition. Their mission is to challenges the research participants to design, build, and operate the most attractive, effective, and energy-efficient solar-powered house, synchronizing the mission to reduce energy consumption, waste, and emission. The house models must have blended values of affordability, consumer appeal, and design excellence with optimal energy production. Since 2002, there has been six competitions being held so far, showcasing the following six most sustainable and energy-efficient house designs for the future:
Powered by a rooftop solar photovoltaic system, LISI generates more power than it uses over the course of a year. The house adapts to a range of climate zones and flexes to meet a variety of lifestyles. In developing LISI, Team Austria was guided by a vision for a healthy, sustainable future and a concept that could adapt to many lifestyles and climates. Viewing the house as a “social creature” eager to find its place in a richly diverse community, Team Austria honors a sense of stewardship in the use of our planet’s most precious resources.
- Renewable and eco-friendly construction and insulation materials made of timber are easily transported and provide indoor climate comfort and carbon-neutrality.
- Changeable architectural elements create a variety of sensory conditions—closing to form a protective cocoon for occupants and opening to allow them to expand their space.
- Two patios create a balance between interior and exterior and public and semi-public spaces.
- The passive solar design, combined with an automated screen and awning system, provides shade to keep the living spaces cool and comfortable.
- A patio herb garden draws water from a rainwater reservoir.
- Generous storage, completely integrated into the walls, frees the primary indoor space from clutter.
- Photovoltaic modules provide an annual surplus, which can be used to power electric bikes or vehicles.
- A centralized utility room contains all the automated mechanical systems the house needs, including a photovoltaics monitor, ventilation, plumbing, and hot water supply.
- Two high-efficiency, air-water heat pumps supply cold and hot water for space heating and cooling as well as for domestic hot water.
- An energy-recovery ventilation unit acts as a heat and humidity exchanger between exhaust air and fresh intake air to keep the living spaces comfortable and healthy.
- A multifunctional subfloor system regulates the indoor climate using water, air, and active cubic capacity.
- A heat-recovering shower tray reduces the energy demand for hot water by almost one-third.
- Through a tablet application, the automated house control hub, energy performance history, and live data can be accessed in an intuitive way.
LISI’s residents are ecologically aware, intellectually agile, young at heart, and contemporary of mind. LISI was designed as a flexible house with potential for serial production. Two economically promising applications were initially identified:
- A sustainable cottage for small lots in urban areas
- A contemporary chalet for mountain and lake resort developments.
Inspired by the Chesapeake Bay ecosystem, the University of Maryland returns to the U.S. Department of Energy Solar Decathlon 2011 with WaterShed—an entry that proposes solutions to water and energy shortages. The house is a model of how the built environment can help preserve watersheds everywhere by managing storm water onsite, filtering pollutants from greywater, and minimizing water use. The photovoltaic and solar thermal arrays, effectiveness of the building envelope, and efficiency of the mechanical systems make WaterShed less thirsty for fossil fuels than standard homes.
The forms of the house highlight the path of a water drop. WaterShed’s split butterfly roofline highlights storm water runoff from each module, directing and collecting it into the water axis at the core of the house. Water used within the house intersects this axis through a consolidated mechanical core.
Spatially, the house is designed as two “shed” modules slid apart along the central water axis and connected by a third module: the hyphen. The two larger modules express the programmatic intent of a live/work environment by physically separating the public and private realms. The hyphen houses the bathroom and highlights the connection between interior water uses and the wetland axis outside.
WaterShed’s holistic approach to water conservation, recycling, and storm water management includes:
- A modular constructed wetland that helps filter and recycle greywater from the shower, clothes washer, and dishwasher.
- A green roof that slows rainwater runoff to the landscape while improving the house’s energy efficiency.
- A garden, an edible wall system, and a composting station to illustrate the potential for improved health, energy, and cost savings with a complete carbon cycle program.
WaterShed features integrated systems that keep the house comfortable under a range of climatic conditions. These include:
- The liquid desiccant waterfall, which serves as a design feature and provides humidity control.
- An engineering system that harnesses excess energy generated by the solar thermal array.
- A home automation system that monitors and adjusts temperature, humidity, lighting, and other parameters to provide maximum function with minimal impact on the environment.
WaterShed is intended for a working couple that can use the house as home and office. This demographic is prevalent within the Baltimore, Maryland, and Washington, D.C ., markets, where there are many individual firms in the fields of consulting, law, and architecture. WaterShed is affordable because the upfront investment in energy‐ and water‐saving technologies eventually provides cost savings given the increasing cost of utilities. For people in the Washington, D.C., corridor, WaterShed provides the opportunity to telecommute, thus reducing travel expenses in one of the most congested areas of the country.
Sustainability Is Skin Deep
Team Germany started with a “focus on the façade,” creating a house that is essentially a two-story cube. The surface is covered with solar cells: an 11.1-kW photovoltaic (PV) system made of 40 single-crystal silicon panels on the roof and about 250 thin-film copper indium gallium diselenide (CIGS) panels on the sides that are expected to produce an incredible 200% of the energy needed by the house. The CIGS component is slightly less efficient than the silicon but will perform better in cloudy weather. The façade’s highly insulating, custom vacuum insulation panels plus phase-change material in the drywall maintain comfortable temperatures. Automated louver-covered windows block unwanted solar heat.
The team is relatively small with only 24 students, mostly architects. But team member Sardika Meyer relates how many others took part. “Even my boyfriend, all the families and friends got involved,” she says. “We had so much support; it was really incredible.” Team Germany finished first in Solar Decathlon 2007, and the 2009 team has relied on members of the 2007 team for guidance.
The Team Germany philosophy was to “push the envelope with as many new technologies as possible.” In particular, the house was designed to maximize PV production and use of the net-metering connection to the electric utility grid on the National Mall. The result is a two-story, cube-shaped building with PV panels on the roof and sides and a single multifunctional living area on the inside. Described by the team as an aesthetic solar design, the house has a bed and other furniture and appliances that fold away or serve multiple purposes.
The extensive PV panel deployment is the most notable feature of the Team Germany house, but other technologies include:
- Custom-made vacuum insulation structural panels
- Phase-change material in both walls (paraffin) and ceiling (salt hydrate)
- Automated louver-covered windows
- A boiler integrated into the heat pump system that allows the system to provide domestic hot water as well as heating and cooling.
- A two-story cube shape that provides maximum dimensions and surface area
- A surface area that is almost totally covered with PV panels—single-crystal silicon on the roof, thin-film copper indium gallium diselenide on the sides
- An expected production of twice the electricity needed
- A single multifunctional space inside
“Made in Germany” is a phrase that applies well to the Solar Decathlon entry from the Technische Universitat Darmstadt, because the team wants to present the German way of building, showcasing German technologies and materials in their solar house, including German oak. The design for the team’s house design appears simple, with an exterior of oak and glass, but the low-tech appearance hides many high-tech devices.
The emphasis on “Made in Germany” products and technologies is apparent in the team’s collaboration with German companies and manufacturers, such as Bosch, which provided three-month internships for two Darmstadt students. That arrangement provided a test bed for the students to study the performance of the systems that will provide hot water and climate control for the house.
“It was very interesting because we had all those experts right next to us, and when we had specific questions, we always got very good answers very quickly,” says Toby Kern, an architecture student who was one of the interns.
After the Solar Decathlon, the house will return to Germany to be used as a solar power plant, as part of the university’s project of a Solar Campus (“Solare Lichtwiese”), through which all buildings on campus will be equipped with building-integrated photovoltaics, feeding electricity into the German power grid.
Germany has a “solar feed-in tariff” that provides a guaranteed price for any solar power that is fed into the German power grid. Because the feed-in tariff is high enough to more than cover the cost of the installation over the long term, the university is selling shares to the public to finance these photovoltaic systems. This yields a return for the investors as the revenue from selling the power is split among them. The Solar Decathlon house will be the first piece in this ambitious project—continuing to showcase the potential of building-integrated solar power generation.
Cubity, developed by Darmstadt University of Technology, is the first energy-plus student housing in the world, offering individual living space with a footprint of just 16 x 16 metres. Duravit supports this innovative project as a forward-looking approach to sustainable living.
The construction of the energy-plus house is based on the “village-within-a-house” concept, as shared functions predominate when students live together. Six two-storey cubes, each composed of two independent living units, are arranged around a central common area, the “marketplace”. In addition to the marketplace, residents have a common cooking area, gallery and terrace. They are adapted to typical student activities.
All the cubes offer an individual place of retreat and focus on private functions, such as sleeping, working and personal hygiene. Duravit products from the Happy D.2 and Darling New series are the ideal complement to Cubity’s young, experimental residential concept. Washbasins and compact WCs add extra convenience without taking up too much space. On a floor area of just 7.2 m² the specially designed fitted furniture, which provides a bed, cupboard, table, chair, lighting, electrical supply and storage space, offers the greatest flexibility in a small space.
The upper storey is reached by a single staircase with a gallery offering access to the individual cubes. Each cube also has a private entrance area.
The entire building is structured in several climatic layers. It uses a reversible air-to-water heat pump to heat or cool the interior. The drinking water is preheated by a hot water storage unit. The heat pump is powered primarily by solar panels on the roof. An underfloor heating and cooling system ensures a balanced temperature throughout the year in the marketplace, which is designed as an intermediate climate zone.
“It’s the Natural Place to Be, No Matter Where You Are” is their design motto. The materials used in the University of Colorado’s home read like a health food restaurant menu. Soy, corn, sunflower, canola, coconut—these are just some of the natural “ingredients” in many components and furnishings (and even tableware) featured in this unique modular home. What’s more, naturally derived fuel will be used to transport the home to and from Washington, D.C.
Using natural materials was one of the team’s five major design goals, along with innovation, energy efficiency, modularity, and accessibility. The result is a sustainable, attractive solar home built almost entirely of recycled and natural materials—one that can go almost anywhere to complement almost any lifestyle.
The Colorado team is especially eager to unveil the innovative, biobased structural insulated panels—BIO-SIPs—used for the walls. Julee Herdt, one of the team’s faculty advisors, developed the BIO-SIP with the help of researchers at the U.S. Department of Agriculture’s Forest Products Laboratory in Wisconsin. It meets all building code requirements and is patented for use in future products. BIO-SIPs merge two commercially available green products: strong but lightweight Sonoboard, made of recycled cellulose materials by Sonoco Company, and BioBase 501, a lightweight foam insulation made of soybean oil by Biobased Systems.
The BIO-SIPs and high-performance window glazings contribute to the home’s energy efficiency. So does the integrated radiant solar thermal system used for space and water heating. “We wanted a nonintrusive, ductless heating and cooling system, and this really fits the bill,” says Kendra Tupper, student leader of the engineering team.
The team also carefully selected the home’s rooftop PV system and building-integrated PV awnings, which provide shade as well as electricity. “Our rooftop PV system is made of 32 SunPower 200-watt panels; they’re around 16%-17% efficient,” says Jeff Lyng, student project manager. After the Solar Decathlon, the home will be set up again and connected to a utility as part of the university’s education and outreach activities.
The 2005 team wants its home to compare favorably with the university’s 2002 Solar Decathlon entry, which took top honors. “Our 2002 goal was to create an energy-efficient solar home that would fit right into an American suburb, so it was a little bit conventional,” says faculty advisor Michael Brandemuehl. “In 2005, students are using more innovative materials and solar technologies to create a modular home for the future.”