The following is an excerpt from Prefabulous + Sustainable: Building and Customizing an Affordable, Energy-Efficient Home by Sheri Koones (Abrams, 2010). The excerpt is from the Introduction.
In green design, symbolism is sometimes as important as substance. In the LEAFHouse, designed and built by students at the University of Maryland, symbol and substance became one.
The three goals of the team were straightforward: to advance sustainable design and construction, to use nature as inspiration for design, and to demonstrate that solar technology is practical for everyday life.
LEAFHouse was designed and built using the best of traditional knowledge about construction married with new and innovative technologies, and utilizing readily available materials in creative and innovative ways. The signature example of this approach is the central “stem” of skylights that run the length of the house. Constructed from FSC-certified wood, ordinary structural steel, and a polycarbonate skylight system, the roof provides an integrated solution in which structure, thermal performance, and daylighting strategies come together.
This prototype house was built at the university and transported to the Mall in Washington, D.C., for the Solar Decathlon in 2007. The University is planning on working with a modular company to develop a version of LEAFHouse to market to consumers.
Machine for Living
The house is strikingly attractive and well proportioned. But the team needed it to do more that look good. The design had to perform all the necessary functions of an ordinary house—such as heating, cooling, lighting, and making hot water— as well as accomplish the simply stated but difficult to achieve goal of becoming a good home for the eventual inhabitants. The systems also had to adapt to the homeowners’ needs and be easy to operate.
Two engineering students developed the Smart House Adaptive Control (SHAC), an automated control system with web-linked intelligence that could track current weather and solar conditions and direct the house to optimize energy use, humidity, light, and water consumption. The system collects data around the house, monitors conditions, and performs tasks to efficiently and economically manage the home as required to create a comfortable environment.
Some of these smart house functions include monitoring and controlling the lighting and liquid desiccant waterfall systems. LEAFHouse’s smart house SHAC system also continually evaluates interior lighting levels and responds to the natural light outdoors by balancing electric with natural light. The system helps control energy use and improve the environment for inhabitants. Homeowners can control dimming levels according to who’s home, the time of day, and the type of activity. SHAC also can advise the homeowner to conserve energy if the extended weather report calls for clouds (solar panels don’t like clouds).
One unique feature of the house is the liquid desiccant dehumidifier, which removes moisture from the air while also serving as an aesthetic waterfall element.
Although the LEAFHouse was hooked up to the grid when it returned to the university, on the Mall it functioned entirely as a solar-powered house, without any city electricity.
The thirty-four solar panels on the roof provided power for all electrical needs. The fortyeight 12-volt batteries could store enough energy when the sun shone to power everything in the house for up to four days. The north/south orientation of the house, with the preponderance of natural light pouring in from clerestory windows that run the length of the structure and from the large glass doors and windows on the south side of the house, works to minimize artificial light needs.
Low-energy LED and fluorescent lighting controlled by a “smart” lighting system and ENERGY STAR appliances helped to further decrease the energy usage. Spray foam insulation kept the envelope of the house well padded to minimize the need for heating and cooling, saving even more energy.
The house was built to adapt to all seasons and to the changing needs of day-to-day life.
With the Murphy bed stowed out of sight, translucent panels surrounding the bedroom open to transform a private space into an entertaining area. Large sliding glass doors open to the deck, effortlessly blending indoor with outdoor space. Louvers were designed to allow the light to enter in the winter and be deflected in the warm months.
The LEAFHouse is back on the University of Maryland campus, set onto a permanent foundation, where it will serve as the office and meeting place for the Potomac Valley Chapter of the American Institute of Architects. There it will continue to educate and inspire.
The Good Stuff
Builder: University of Maryland
Location: National Mall, Washington, D.C.
Size: 800 square feet
Indoor liquid desiccant waterfall for dehumidification
Solar water heating system
Drain water heat recovery system
Storm water management system
Locally harvested wood
FSC-Certified wood for framing and finish
Recycled corrugated metal siding
Soy-based spray foam insulation
Smart house system
Radiant floor heating
Energy Star appliances
Renewable and recycled materials
Fluorescent and LED lighting
Energy recovery ventilator
FSC-Certified eastern white pine
Read the original article, "Prefab Homes: Green, Efficient and Affordable."