Page 24 RAIN February/March 1983 the decrease of immediately available heat transferred by convection to the adjacent living rooms, as more heat was stored in the mass and transferred at a later time. Another effect of the increased mass was that it compromised the greenhouse growing conditions by not allowing temperatures to drop below 50° F, which is necessary for hardenirig-off of spring seedlings. Realizing the limits to increasing the mass, the project then installed a site-built mylar insulating curtain at a cost of under $5 per square foot. Where all other retrofit measures of this project proved to be cost-effective, the insulating curtain did not, primarily because the greenhouse was being used for multiple purposes. Fuel savings, however, proved to be the bonus in the project. Originally consuming over 1000 gallons of heating oil per year, the building now uses only 84 gallons, supplemented by a woodstove in each unit of the duplex. Tom Marvin of Ashland supplied his home electricity from batteries charged by a gasoline generator for about four years. More recently he has installed a four panel array (approximately sixteen square feet) of Arco solar photovoltaic (PV) cells. Each panel contains 35 cells which convert sunlight directly into low voltage d.c. electricity used to charge batteries. In 1980 Marvin received a grant to improve his photovoltaic system with a tracking device. Tlie device increases the power output of the photovoltaic array by orienting it toward the sun, adjusting the array to follow the sun's daily path and to account for seasonal changes in the sun's position. "Monitoring the system becomes an exercise in watching the seasons and the sky. Learning to live with what it produces and learning how to utilize every bit of its capacity are meaningful pastimes in themselves," says Marvin. Marvin's solar powered electrical system powers his lights, stereo, blender, soldering iron, television, and even a micro-computer — all of which are designed to run on 12V d.c. The system does not generate a.c., the Tom Marvin's tracking device for a photovoltaic array. power commonly required for household appliances. Marvin meets these needs through other means. A small gas generator is used for power tools; his refrigerator and range are propane operated; water and space heating are provided by a combination of solar and wood energy. Appliances are now being engineered for low power requirements, and architectural developments are reducing power needs. "Rather than trying to match 'standard' power needs with PVs," says Marvin, "we should study how we can adapt our needs to this incredibly beautiful new source of electricity. Conservation takes on a new meaning: it is no longer simply a goodwill chore or an economic necessity, but an integral part of living." Many Portland residents are using solar energy systems, disputing the claim that solar cannot work under Portland's grey skies. Yet low income inner city residents—people who could strongly benefit from solar technology — are the least likely to be aware of it. A minority member of the construction trades for over eleven years and an inner city resident himself, James Cason is particularly aware of this dichotomy. To increase awareness of solar energy within his community, Cason applied for a grant to install solar water heaters in the homes of five low income families. After publicity in city and neighborhood papers and on the radio, over seventy families asked to be considered and over forty site visits were conducted. However, many were reluctant to participate in a federal program, especially since the issue of the final ownership of the collectors was unresolved. No one expects the USDOE to take the collectors, but turning over ownership of property from the Federal government to individuals has been a problem since the beginning of the grants program. Selection criteria were developed to narrow the field of participants. The criteria included that the household be low income; that space be available for a water tank; that the roof be in good condition; and that the family be willing to participate in an open house and monitor the system. The families selected represent a variety of ethnic groups, family sizes, and levels of knowledge about solar energy. Cason's project uses a commercially tested drain down system, sized to meet Oregon Department of Energy tax credit specifications — supplying a minimum of 50 percent of the family's hot water needs. Four solar water heater installations have been completed. The first and fourth installations were conducted as workshops. The first open house drew 43 people and was publicized with neighborhood signs, public service announcements, and word-of-mouth. Neighbors viewed the completed installation, asked questions, and spoke with the hosts about their experience. Information on solar feasibility in Portland, the cost of installation, expected energy savings, and estimated payback periods were provided at each site by energy information specialists from Portland Sun who worked with Cason.
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