Design Principles
Systems Description
Systems Design Overview
Solar and wind generated electricity, two qualities of water, and sewer services are provided to each lot. The project is broken down into 3 blocks of 7 homes, which we call a neighborhood. Each neighborhood has solar and wind generation, battery storage, and inverter. Each neighborhood has a 50,000-gallon underground tank for storing water from rooftops. Each neighborhood has its own constructed wetland sewage system. This modular design allows utilities to be built as the project develops, rather than all at the beginning. Low-grade water systems (collected across the land in swales/diversion drains and held in ponds) are provided for the entire project rather than per neighborhood.
Agriculture is an important part of the project. 85 percent of the food eaten in Iowa comes from somewhere else, and we feel that it is important from an environmental, economic, and cultural standpoint to grow food locally. Useful and edible plants are widely planted. There is common greenhouse space, and we are helping to establish two independent agriculture related businesses by providing land and greenhouse space and a market for plants and food. One business is Abundance CSA, an organic market garden that provides locally grown vegetables and herbs to 25 families around Fairfield. Another business is a permaculture plant nursery for the Midwest.
For home design, an integrated, high performance design approach is being used. All homes are heavily insulated, use the appropriate glazing for each façade, and use earth tubes to temper incoming air in summer and winter. We have the additional design constraint of Maharishi Sthapatya Ved, which is an ancient system for determining the orientation and placement of buildings that has been recently revived by Maharishi MaheshYogi. Each system (energy, water, waste and nutrient recycling, agriculture, and Maharishi Sthapatya Ved) will be described in more detail next.
Energy
Energy Use and Metering
A key element in making permaculture-based utilities affordable is to use energy and water wisely. This does not mean doing without services. Using energy wisely means careful attention to design and the efficiency of systems, technologies and appliances. The first home in the Abundance, the Walton house, which has been occupied since 2001, is 3600 square feet, has 5 adult occupants, and uses less than 100 kwh per month. A conventional home of that size in this area uses about 1000 kwh per month to provide the same services.
A typical energy budget for 120 kWh per month is shown below. Fig. 4: Typical Ecovillage home electrical energy use
As you can see from the chart, the largest energy users are refrigeration, lighting, and HVAC. Energy use guidelines have been developed that help homeowners select appliances and systems for their homes. These guidelines recommend things like daylighting, high efficiency compact fluorescent and LED lighting, laptop computers, horizontal axis washing machines, earth tube cooling, and control of phantom loads. The net result is that the same or better services as used in a conventional home are delivered with 1/4 to 1/10 of the energy use. We have also been careful in the design of the common water pumping and sewage systems, using the most efficient pump technology available and gravity feed solutions whenever possible. We are working to implement energy and power meter for each home, but currently only one home has energy/power metering. We hope to implement a web-based system soon. In a situation like this, where energy systems are shared and some homeowners may be better educated and careful about energy consumption than others, there is always the possibility that someone will use more than their share of energy. Currently we monitor the situation daily and haven’t had major problems with this. We spend a lot of time with new families in the first few months as they learn about energy efficiency and the use of solar and wind generated electricity. Our experience with dozens of solar and wind powered homes in Fairfield over the last 15 years indicates that biodiesel back-up will be required less than 2% of the year. My own home solar and wind system sometimes goes for years without the use of a back up generator.
Energy Resources
Southeast Iowa has abundant solar and wind power resources, and the complimentary nature of the two together provide a reliable power supply. Below is a chart showing the relative amount of energy available from each source per month, averaged over a 20-year period.
Fig. 5: Monthly solar and wind, Fairfield, Iowa7 (For the purposes of this chart, the solar array is sized to match annual output of wind generator.)
As you can see, the months that are not sunny are often windy. What is not shown here is that solar and wind power are complimentary on short-term cycles as well. When a front comes through, it gets cloudy, but it also gets windy. At night, when there is never sun, any wind is a bonus. The developers have been involved with the installation of dozens of solar and wind powered homes in the area over the last 15 years, and two of us have been living with solar and wind power in Fairfield for 15 years. Our experience backs up the data from this chart indicating that a combination of solar and wind power provides a very reliable energy source in this area.
Energy System Design and Modeling
Each neighborhood (7 homes) will have an 5kW PV array, a 7.5 kW, 23-foot diameter wind generator on a 100-foot tilt down tower, and 100 kWh of lead acid battery storage, a 5600-watt sine wave inverter, and an 5kw biodiesel back up generator. Currently, we have a 3 kW whisper/southwest wind power wind generator, a 4 kW trace/zantrex sine wave inverter, 24 kWh of lead acid batter storage, and a 6 kW biodiesel back up generator.
Fig. 6: Innovative tower locally designed and designed and fabricated by Nelson LaFrancis 9 (Model shown – actual tower is under construction)
Fig. 7: Energy system design
The Iowa Energy Center has an on-line modeling program for wind, solar electric, and solar thermal systems that is fairly accurate for any location in Iowa. Tom Factor, who is located in Fairfield, developed both of these tools. For Fairfield, the average annual kWh production per kW of peak PV capacity is XXXX kWh (With current module efficiencies, this works out to about XXXX per sq ft) The average annual kWh production per square foot of wind generator blade swept area is 59.4 (641.52 kWh per square meter).
Water
The village relies on rainwater for water supply. 16 million gallons of water falls on the 16 acres of Abundance Ecovillage in an average year. There are three systems for collecting and storing water. The first system collects and stores rainwater from roofs in underground storage tanks. This system provides household water for washing and bathing. The second system collects surface water and stores it in ponds. This system provides water for agriculture and for flushing toilets. Water from the first and second systems are pumped using high efficiency pumps (DC positive displacement pumps). The third system is rainwater storage in the ground. This system provides water storage for trees and plants. These systems are described in more detail next.
Rainwater catchment
Each neighborhood will have a rainwater catchment system. Water will be collected from the roof of each home in the cluster and directed to a storage tank. The storage tank will be a below ground concrete tank holding 40,000 gallons. Each storage tank will have a pump house. The pump house will filter and pressurize the water and pipes will deliver pressurized water to each home. This filtered pressurized water will be used for bathing and washing. The first system is completed and is providing water to all the current houses.
Agricultural water from ponds
Water falling on the land is collected in swales and ditches and directed to ponds. Pond water is pressurized and delivered to each house for flushing toilets, watering gardens, and washing vehicles.
Water stored in ground with swales
Water is stored in the ground in the area around the roots of plants. Prairie plants are especially good for this as up to 60% of the mass of the plant is below ground, and the roots of the plants go up to 16 feet below the surface, breaking up the soil and making tiny passages for water to percolate. Hundreds of thousands of gallons of water per acre can be stored in the ground this way. During dry times, this water will be available to trees and other deep-rooted plants.
Waste and Nutrient Cycling
The sewer and waste water handling systems allow valuable nutrients to be recycled and safely reused. Flush toilets are used. Black and greywater are separated at each house. Greywater can be used at the lot or can be sent to a greywater processing system that serves the whole project. Toilet wastes, blackwater, flow into a tank. Liquids flow out of the top of this tank into a constructed wetlands system. The constructed wetlands system consists of a bed of gravel 18 inches deep planted with a variety of aquatic plants (cattail, arrowhead, etc.). The aquatic plants and bacteria living on the surface of the gravel will further process the water and absorb nutrients.
We have designed and installed a methane digester under the direction of Methane Guru Al Rutan. This continuous process digester will process the waste from 8 to 10 homes. For optimum gas production, the digester needs to stay above 90 deg F year round. Very little heat leaves the tank, and we only have to supply the losses from the tank to its environment and any energy required to heat material coming into the digester. Our design solution is to use high insulation around the tank, a water bath that is heated by active solar, and a unique solar building. Mr. Rutan designed a greenhouse that uses movable insulation and glazing for climate control, utilizing garage door track technology. We were unable to complete his innovative movable insulation design before his death a year ago, but we look forward to carrying on his work and completing his vision in the future.
A photo of the digester during installation is shown below. Fig. 8: Methane Digester Installation
Agriculture
We’re working to fill the landscape at Abundance Ecovillage with annual food plants, perennial food plants, medicinals, plants with a craft or utility use, and their associated helper or guild plants. Our model for the density of planting and the emphasis on edible and useful plants is Village Homes in Davis California. We have been fortunate to have Doug Bullock, Bruce Hill, Jerome Ostentowski, Michael Corbet, and Tom Wahl from North America and Kay Baxter from New Zealand assist us with project design and species selection. We’ve got 400 or so species of perennial plants, some planted out and some in a nursery. It is taking longer than we had hoped to build out the project, and it is difficult to establish the permanent plantings while construction is ongoing. We have established 100 or so fruit trees, a vineyard, bramble fruits, nut trees, and asparagus. We’ve made more progress in establishing our annual crop agriculture. We’ve installed 4000 square feet of greenhouse, and we have established community garden spaces and a CSA farm, Abundance CSA. Several people have attempted to start a permaculture plant nursery, and this year another person is giving it a try. In assessing the potential for permaculture systems in Fairfield, Doug Bullock said, "I think there is tremendous potential for really kick-ass permaculture systems here - Iowa has the greatest diversity of native fruit and nut trees of anyplace I’ve seen outside the tropics, the soils are moisture and nutrient retentive, and most of the rainfall comes during the growing season" We’ve got a mix of selected varieties, seedlings, and grafted, named varieties. The common names of natives and a few of the non-native edible species are listed below.
TABLE 2: COMMON NAMES OF SOME ECOVILLAGE PLANTS Mulberry Aronia Shipova Persimmon Akebia Sea Buckthorn Black Walnut Serviceberry Maypop Paw Paw Bush Cherries Edible Dogwood Native Plum Elderberry Gooseberries Hardy Kiwi Medlar Hazelnut Chestnut (Badgersett varieties) Butternut Blackberry A complete list of plants at Abundance Ecovillage http://www.abundance-ecovillage.com/pmwiki/pmwiki.php/TheAEVCommunity/VillageElements
Maharishi Sthapatya Ved
Sthapatya Ved is an ancient system of architecture from India. It prescribes the placement, proportion, orientation, and materials for human habitats, from homes to neighborhoods to cities to countries. The central tenant of Sthapatya Ved is that the orientation, proportion, and placement of the built environment have dramatic effects on occupants. The purpose of Sthapatya Ved is to maximize the positive effects and eliminate the negative ones, to bring the occupants of the building more in tune with natural law. Maharishi Mahesh Yogi, the founder of the Transcendental Meditation movement, (the US branch of Transcendental Meditation is headquartered in Fairfield) is reviving the knowledge of Sthapatya Ved. This revived Sthapatya Ved is called Maharishi Sthapatya Ved. There has been over $150,000,000 worth of Sthapatya Ved construction in Fairfield over the last 8 years. Fairfield now has the largest concentration of Sthapatya Vedic buildings outside of India. The reports from the occupants of these buildings have been very positive, and there is a continuing strong demand for Sthapahya Ved housing in Fairfield.
However, most Sthapatya Vedic construction has not taken into account basic energy efficiency and environmental design. One goal of our project is to incorporate environmental and ecological design principles into Maharishi Sthapatya Ved. Maharishi Sthapatya Ved introduces a variety of additional design criteria, none of which are insurmountable in developing an energy efficient and earth friendly home. Some of these criteria include no recycled materials, emphasis on the use of natural materials, orientation of homes, and placement of the rooms with regard to the path of the sun. This is not, however, the same kind of placement and orientation that is recommended by passive solar design. Here are a couple of examples: Sthapatya Ved requires that the door of a home face east or north, never south. The roofline of a home must run north-south. Yards are surrounded by a protective fence, and a decorative ornament called a Kalash is placed on the roofline. Maharishi Sthapatya Ved design, however, is a complex and involved discipline, and cannot be summarized by rules of thumb. Design reviews are done by regional organizations authorized by Maharishi Mahesh Yogi. The entire project layout has been reviewed and approved, and home plans are required to have Maharishi Sthapatya Ved review and approval.