techdirections November 2012 : Page 20

Designing a Self-Sustaining Community By Harry T. Roman harry661@verizon.net W E’VE heard a great deal in recent years about designing self-sustaining com-munities, organiza-tions that can subsist independently on what they make. Planning for this kind of community is challenging— today most of us take for granted having essential services like water, sewage, communications, natural gas, and electricity delivered right to our doorstep. Self-sustaining communities seem to hark back to an earlier time. In this design challenge, STEM educators can explore with their students the subject of electricity and how technologists and engineers might go about making a small community self-sustaining in terms of electrical service. Getting Started The design challenge starts by explaining to students that a new community is to be built in a rural area where no electric lines currently exist. The residents want to both live and work in the community and they want it to be self-sustaining in terms of their electricity needs. The stu-dents are to function as engineering consultants to the community, help-ing them determine how they can be self-sufficient regarding electrical service. Students must first know how the residents will live in the community. Harry T. Roman is a retired elec-trical engineer, inventor, writer, and technology and engineering education advocate. Will there be a central residence for them or distinct housing units that must be connected together? Needless to say, this can make a big difference in what energy sources are used. So it makes sense to begin with a plan layout for the community. Let’s assume that 100 people will live there, both children and adults, and that there will be a mix of large build-ings and individual dwelling units. You may want to develop a hypo-thetical plot plan of the community with building layouts and some rel-evant statistics that student design teams can mull over. Then give stu-dents some room to challenge your layout if during the course of their planning they come up with valid reasons for changes. Since this new community will be built from scratch, we’ll assume that it will be well built, incorporating energy-conserving practices, appli-ances, and lighting. Energy consump-tion for the community’s buildings will be small compared with that of most buildings now in existence. We can assume that the community will need no more than 100 kW of electric power to completely run itself, including any manufacturing and processing equip-ment that residents must operate. The community will be located in a temperate climate, with relatively little need for heating and air condi-tioning. It will be located on 30 acres of land in a quiet valley with a me-andering river. Let’s further assume that it is an artists’ community, and that residents will make products for sale to other communities. The inhabitants of the community have chosen to call their community the Green Arts and Crafts Society. The Design Challenge With students knowing the layout of the buildings, the community’s total energy needs, and some infor-mation about the environment in which it will be built, it now becomes a matter of identifying and consider-ing energy choices and making some tradeoffs. Students should research some potential energy sources that they might use, such as: O Solar photovoltaics O Wind power O Water power O Clean-burning small engines O Waste burners that can produce electricity O Fuel cells While not a comprehensive list, this will serve to get students going. Encourage them to think broadly across the energy alternatives they identify. Have them evaluate their options in a chart-type format, con-sidering the pros and cons of each alternative and then comparing and ranking them as to suitability, cost, and environmental impacts. Remind them to keep in mind how the resi-dents in this community have identi-fied themselves. Evaluating energy alternatives will take a fair amount of time research-ing websites and other resources. Through their research, students will hopefully find information on engi-neers who have worked with similar situations. Have students discuss and ad-dress basic questions like: 20 tech directions X NOVEMBER 2012

Designing a Self-Sustaining Community

Harry T. Roman

<br /> WE’VE heard a great deal in recent years about designing self-sustaining communities, organizations that can subsist independently on what they make. Planning for this kind of community is challenging— today most of us take for granted having essential services like water, sewage, communications, natural gas, and electricity delivered right to our doorstep.<br /> <br /> Self-sustaining communities seem to hark back to an earlier time. In this design challenge, STEM educators can explore with their students the subject of electricity and how technologists and engineers might go about making a small community self-sustaining in terms of electrical service.<br /> <br /> Getting Started<br /> The design challenge starts by explaining to students that a new community is to be built in a rural area where no electric lines currently exist. The residents want to both live and work in the community and they want it to be self-sustaining in terms of their electricity needs. The students are to function as engineering consultants to the community, helping them determine how they can be self-sufficient regarding electrical service.<br /> <br /> Students must first know how the residents will live in the community. Will there be a central residence for them or distinct housing units that must be connected together? Needless to say, this can make a big difference in what energy sources are used. So it makes sense to begin with a plan layout for the community. Let’s assume that 100 people will live there, both children and adults, and that there will be a mix of large buildings and individual dwelling units.<br /> <br /> You may want to develop a hypothetical plot plan of the community with building layouts and some relevant statistics that student design teams can mull over. Then give students some room to challenge your layout if during the course of their planning they come up with valid reasons for changes.<br /> <br /> Since this new community will be built from scratch, we’ll assume that it will be well built, incorporating energy-conserving practices, appliances, and lighting. Energy consumption for the community’s buildings will be small compared with that of most buildings now in existence. We can assume that the community will need no more than 100 kW of electric power to completely run itself, including any manufacturing and processing equipment that residents must operate.<br /> <br /> The community will be located in a temperate climate, with relatively little need for heating and air conditioning. It will be located on 30 acres of land in a quiet valley with a meandering river. Let’s further assume that it is an artists’ community, and that residents will make products for sale to other communities. The inhabitants of the community have chosen to call their community the Green Arts and Crafts Society.<br /> <br /> The Design Challenge<br /> With students knowing the layout of the buildings, the community’s total energy needs, and some information about the environment in which it will be built, it now becomes a matter of identifying and considering energy choices and making some tradeoffs. Students should research some potential energy sources that they might use, such as:<br /> <br /> -Solar photovoltaics<br /> -Wind power<br /> -Water power<br /> -Clean-burning small engines<br /> -Waste burners that can produce electricity<br /> -Fuel cells<br /> <br /> While not a comprehensive list, this will serve to get students going. Encourage them to think broadly across the energy alternatives they identify. Have them evaluate their options in a chart-type format, considering the pros and cons of each alternative and then comparing and ranking them as to suitability, cost, and environmental impacts. Remind them to keep in mind how the residents in this community have identified themselves.<br /> <br /> Evaluating energy alternatives will take a fair amount of time researching websites and other resources. Through their research, students will hopefully find information on engineers who have worked with similar situations.<br /> <br /> Have students discuss and address basic questions like:<br /> -How will they achieve the 100 kW electric load size?<br /> -Will they use one or several energy alternatives?<br /> -How will they distribute the system(s) from one location or several/ many?<br /> -How will they physically interconnect the system(s) if necessary?<br /> -How will they cope with their energy system(s) being out of service?<br /> -How will they bring in fuel if they need it to run their system(s)?<br /> -How will they determine who will run their system(s) and how it will be maintained?<br /> -If they plan to store energy, how will they do so?<br /> <br /> Again, this is not an exhaustive list, but one designed to stimulate students’ thinking. Instruct them to draw diagrams and pictures to illustrate their thinking and team designs. Remind them they are acting as consultants and must look at the total picture and conditions—they should not interject personal choices or preferences. Like real-world engineers, they should do what they perceive as best for this community.<br /> <br /> The energy systems students select for review will come in different sizes or physical dimensions. How best to use the space (or volume) of this design challenge is up to student teams to consider.<br /> <br /> Additional Challenges<br /> You can vary this design challenge to alter the lessons learned. For instance, how might this exercise correspond with designing:<br /> <br /> -A space station?<br /> -An island community?<br /> -A nuclear submarine?<br /> -An arctic science and observation station?<br /> -A remote weather station?<br /> -A lunar colony?<br /> -A village in an undeveloped country?<br /> -A vacation resort?<br /> -A military base?<br /> -An emergency aid station for people affected by a natural disaster?<br /> <br /> Many of the concerns that arise in these varied situations are similar. Often thinking about one situation can spark interesting thoughts about other applications. Ask students to think like NASA engineers or military ship designers. Have them think about how design concerns for a compact space vehicle or nuclear submarine compare with the 30 acres of land available for this small community design. What parallels or insights come to mind?<br /> <br /> Final Reports<br /> Each team should produce final written reports that include drawings, diagrams, plans, and layouts. Ideally, teams would also make oral presentations to the class describing their final designs and the reasoning behind them. You might also want to have students build models of their communities, as architects and land planners often do. Different students think in different ways and can most effectivley convey their ideas in different formats.<br /> <br /> Finally, the most important point of this activity is to have students both learn and enjoy a STEM challenge.

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