Live Like a Leaf
The Leaf Community is the first sustainable community created in Italy.
In a world of growing economic complexity, where the consumption of goods and resources is quickly increasing, communities need to find sustainable solutions to economic challenges. In order to survive, we have to change the way we think and act. We have to give greater value to the things we consume in everyday life, and we have to recognize and honor the link between human beings and the natural environment.
The Leaf Community represents a real change—a place where people and nature meet. The Leaf Community came about because a group of innovators were determined to create a positive relationship between technology and nature. A focus on tradition and innovation characterizes the community—the first eco-sustainable, completely integrated community in Italy, inaugurated on June 25, 2008. It is called the Leaf Community because, like a real leaf, it creates and distributes the energy it needs to live and thrive. In the Leaf Community, energy is captured from the sun, water, air, and earth, and is transformed, stored, and released through a distribution network—just as it is in a leaf.
In the Leaf Community, it’s possible to live in a zero carbon house, travel in an electric or hydrogen-fueled car that is charged using renewable energy, send children to a solar-energy school, where they are educated to respect the environment, and work in eco-friendly industrial sites, perfectly integrated with the natural environment, which create and use renewable energy. Approximately 290 people work at Leaf. Industries include monitoring, testing, and quality control systems; integrated solutions for industrial automation; information and communication technology; and energy management.
Industrial buildings are equipped with heat pumps, thermal power plants, daylighting systems, and building automation—all designed to promote a rational and efficient use of energy. The community includes a micro hydroelectric power plant with a water head of 1 meter that produces 160 MWh per year of energy (enough to meet the energy needs of more than 60 families), while eliminating 90 metric tons per year of CO2 emissions.
The flagship of the community is the Leaf House. It’s a clean-energy laboratory, a place to be studied and visited, introducing people to and educating people about a sustainable future. The first house built in the Leaf Community, it consists of six flats, four for families and two for couples. The Leaf House is a real house, where real people live and continually monitor the amount of energy and resources they consume (see Figure 1). Using the available data, and extrapolating to an entire year, I calculated that the Leaf House will produce, with its PV and solar-thermal systems, and consume 26,500 kWh per year of electricity, eliminating about 18 metric tons per year of CO2 emissions, and 10,200 kWh per year of heat energy, eliminating about 2.5 metric tons per year of CO2.
The nature of the site, the sun and wind exposure, the vegetation, and the level of humidity all influenced the design of the Leaf House. The required energy is produced entirely from renewable resources without CO2 emissions. A roof-integrated 150 m2 PV system covers the entire surface of the south-facing roof. The Enel Company installed a system for the production, storage, and use of hydrogen for generating electricity. During periods of maximum exposure to sunlight, the energy generated by the PV panels meets the energy demands of the Leaf House, and also powers an electrolyzer that breaks down water molecules into hydrogen and oxygen. The hydrogen produced is stored in a system that utilizes metallic hydrates to store the hydrogen. A fuel cell reconverts the hydrogen into electricity for use at night or on cloudy days when the sun is not available to produce electricity.
This cutting-edge energy storage technology is the focus of intensive study and research, by Enel and the Loccioni Company particularly regarding its application for managing renewable energy sources in sites that are not connected to the grid.
Like a real leaf, the Leaf House uses the energy that it extracts from the sun. It uses this free and renewable energy to heat water. The water, which is used for DHW and space heating, is heated with thermal-solar collectors, integrated into the building and supplemented by a geothermal heat pump.
The geothermal heat pump uses three 100-meter vertical pipes to extract heat energy from the earth. The heat pump uses that energy to provide for cooling and for heating, eliminating the need for a boiler and an A/C system. On most summer days, it is not necessary to use the heat pump, since the water is cooled automatically as it passes through the underground pipes. The heating-and-cooling system works efficiently because the soil in the area is wet, and the wet soil facilitates thermal exchange. A radiant floor heating system circulates water at 82°F (28°C) instead of 140°F (60°C), the typical water temperature for a conventional radiator.
The high heating efficiency of the radiant system (or any heating system) depends on the thermal insulation in the building. For this reason, the walls of the Leaf House are made with an external layer of expanded polystyrene (EPS). The EPS has a U-value of 0.36 watts per square meter degree Kelvin (W/m2 K), or an R-value of approximately 16 in English units. From the outside in, the walls consist of a plastic plaster finish coat, a layer of EPS, a layer of concrete mortar, and a layer of Poroton brick; the inside surface is finished with plaster mortar. The entire wall has a U-value of 0.15W/m2 K, or an R-value of approximately 38 in English units.
Before it enters the flats, outside air is heated in winter and cooled in summer, using the water produced by the heat pump. Sensors measure the temperature of the indoor air, the presence of CO2, and the humidity, and then activate the ventilation system. This is an improvement over just opening the windows. If someone does open a window, the system will automatically shut off to avoid wasting energy. The fresh intake air is naturally preconditioned; it passes through a 10-meter underground duct before it reaches the air handler.
Rainwater is collected in a tank buried under the garden; it is used for flushing toilets and for irrigation, reducing total water consumption by 50% (see Figure 2). City water that is used for other domestic purposes is pretreated in the kitchen to make it more pure and drinkable. The kitchen sink has a three-way valve: hot, cold, and potable. This means that no one in the Leaf House will buy water in bottles manufactured in a process that emits CO2 —bottles that are thrown out when they are empty.
All of these technologies are managed by a control system that is the heart of the Leaf House. There are more than 1,000 sensors and monitors for the various systems inside the house. The alarm system, the remote house-testing system, and the appliance settings are all integrated here.
Whirlpool, a leader in developing high-performance appliances, has supplied every apartment with a Green Set of its most water- and energy-efficient electrical appliances. Whirlpool has also created a special loft in the Leaf House, called ZEOS (Zero Emissions Open Space). The loft is a live-work space with an open design that can be organized in many different ways. At present, the loft is used as a multimedia communications and research platform; Web cams and an interactive Web site let the world see inside the Leaf Community. Visits by journalists will be organized regularly, with a different theme each time. A careful design makes the loft an ideal location to host TV shows and interviews on green issues.
ZEOS also gives Whirlpool an opportunity to experiment with new concepts and new designs; the loft is a real-life, full-scale laboratory for innovation. In the near future Whirlpool will install the first working prototype of Greenkitchen, a suite of green technology for the kitchen, in ZEOS, and showcase this to the world.
Sharing Leaf with the World
The Leaf House is an example of ideas and technology that can be exported to other countries. In Great Britain, starting in 2016, all new homes will have to be zero emissions for heating and cooling, hot water, ventilation, and lighting. This corresponds to Level 5 of the Code for Sustainable Homes, a new standard, introduced in 2008, that rates new homes at 0 to 6 based on their performance in nine areas of sustainability. Level 0 is the base level; a house rated 0 meets the current regulations. Level 1 represents a 10% energy efficiency improvement over the current regulations; Level 3 represents a 25% improvement, and Level 4 represents a 44% improvement. Level 6 represents a zero carbon emissions house. By 2050, 70% of new homes in the U.K. will be zero emissions. The information gained from the Leaf Community may help the British reach that goal.
Clara Ceppa is a research fellow in the Department of Architectural and Industrial Design at Politecnico di Torino, Italy.
The Leaf Community came about through the efforts of Loccioni Company, the founder of the community; Enel, the largest power company in Italy; Whirlpool Corporation; Beckhoff; Cisco Systems; Faam; IGuzzini; Ikea; National Instruments; Rittal; Schüco; Siemens; Viessmann; and other companies.
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