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tree houses and private dwellings on the property. This arrangement is dependent on sufficient light to charge a battery. Once charged, the battery powers twelve-volt lights and music equipment salvaged from automobiles, boats, and recreational vehicles designed for direct current applications.

Solar Dehydrator

The solar dehydrator is designed to provide a nonelectric option for the preservation of food. To function, the dehydrator depends on its capacity to achieve and sustain the elevated temperatures and adequate ventilation necessary to induce drying, and in conducive meteorological conditions. Hot, dry, windy days reduce the amount of time neces-sary to dry effectively, while damp, cool weather inhibits the process. Drying time is affected by the dryer design, the weather, and the specific plant material to be dried.

The dehydrator comprises various components designed to capture and transmit the sun’s energy to the contained plant material. Our fabricated

the form of electricity so we can connect directly to the existing electrical grid.

We also use solar panels directly or in conjunc-tion with batteries to power remote equipment on the farm. In these efforts we have experimented with water pumping. Solar water pumping is most

A full view of the system after completion A small solar panel is hooked up to two car batteries to provide the living space with a small light and enough power to operate a CD player.

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unit collector consists of a metal box that has been painted black and covered by a transparent sheet of glass. This 11⁄2 by 3 foot box is approximately six inches deep and is attached to the unit such that the angle from the horizon is approximately 35 degrees. The unit faces due south to capture the sun’s radiation throughout its daily journey. This box has ventilation holes at the top and the bottom to enhance the forces of convection and to propel the heated air up through the plant storage element of the collector.

The plant container device consists of stacked shelves with plastic mesh screen bottoms to allow the air to flow through the material. It is important not to utilize galvanized metal screening for these shelves because the coating will contaminate the food. These

Glass front panels of the solar dehydrator absorb the sun’s heat. Removable screen frames allow for access to drying plant material.

A close-up view of the fire box

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the safety and comfort of the cooks with regard to the ergonomics of these appliances.

The solar ovens concentrate the energy of the sun into an insulated box. This box accumulates heat to temperatures necessary for baking, relying on the greenhouse effect to concentrate the energy of the sun into the enclosure. While different styles abound, all units consist of an oven portion in which the food cooks, along with a means to amplify and accentuate the energy from the sun. When I was at SEI, for example, we constructed an effective oven using the simple materials of cardboard, newspaper, plastic wrap, aluminum foil, and masking tape. We also created an oven with glazing from an old sliding door that could cook eight dozen cookies at a time.

We have two manufactured sun ovens that are commercially available for around two hundred dollars. They consist of an insulated box with a glass seal in which a gallon pot can reasonably fit; we have cooked whole chickens as well as loaves of bread in these units. Attached to the box is a system of mirrors arranged to focus the sun’s energy into the oven. Black enamel pots with lids are more effective

shelves are on racks to allow them to be emptied or refilled inside to avoid windy or wet weather.

The design of our dehydrator includes a wood-fired heating element. Under the storage unit is a firebox that provides heat directly to the chamber above. This augmentation is particularly effective during the shorter, cooler days in the fall. The smoke from the fire is channeled through the end of the box and out a chimney on the top so the material is not tainted by the smoke.

Interestingly, our barn has similar qualities, and we utilize it as a giant dehydrator. During the summer months the loft of the barn can become unbearably warm. The aluminum roof is painted black and is inclined toward the sun to collect the full day’s solar journey. Inside the loft there is ample vertical height to hang leafy vegetables and root crops such as garlic from the ceiling to dry.

Solar Cookers

Solar cookers are designed to reduce our reliance on wood, electricity, and fossil fuels to prepare our meals. There are two main genres of solar cookers: those that function as ovens by augmenting the greenhouse effect and those that operate as a cook-top by using parabolic geometry to create a specific point of heat.

The oven must be movable so the glazing collector can directly face the sun as it moves across the sky. A crucial element in the design of these structures is the capacity for the hot cook-ing ingredients to be maintained upright in their vessel as the cooker tracks with the path of the sun. The construction must be adjustable to the varying incidence of the sun throughout the year and be durable enough to withstand the wind. Some solar ovens are designed for the outdoors in fixed, permanent locations, while others are less weather-proof and more readily storable. For all of the cooking equipment it is important to consider that hot and heavy cooking equipment is difficult to transport and monitor. Design should consider

Sun ovens are an easy and practical way to cook beans, grains, and stews.

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Later during my travels in Argentina, I encountered this design again at Gaia. While we have been unable to replicate the versatility of either the SEI or Argentinean units here, we have constructed a parabolic cooker from a salvaged satellite dish. This huge unit was difficult to adjust and fix in place, though it was extremely powerful. The power of the unit forced the cooks using the equipment to wear welding goggles and cover their skin for protection from the intensity.

conductors of the heat than reflective stainless steel or aluminum pots. It is important not to use mate-rials that will release toxic gases when heated. At times moisture can build up on the interior glass and obscure the box, limiting the capacity of the unit. Wind can also slow the process by chilling the device, or tipping the lightweight units over, spilling the contents. Still, these units are reliable on clear days throughout the year, except when tempera-tures are less than 32 degrees.

I enjoy cooking with solar ovens because, unlike with gas or wood, it is difficult to burn food to a black and unpalatable state. Because there is no direct source of heat, that focal point for combus-tion does not exist. While some items may dry out, I have not ruined food because of inattention. If the solar cooker is left unattended the sun’s path progresses and the cooking ingredients cool, which protects them from being overcooked.

To minimize time spent adjusting the unit, I estimate the perfect setup for the unit in relation to the sun’s location thirty minutes into the future. Therefore for the next thirty minutes the tempera-tures will rise, and I can make another adjustment in an hour to further intensify the heat if need be. The hours between 10:00 a.m. and 2:00 p.m. offer the maximum solar intensity, although I have success-fully started food earlier and later in midsummer. In full sun on a 70-degree day in the summer, a pot of rice or beans will cook in two hours or less.

The second style of solar cooking is commonly referred to as parabolic cooking. This cooker utilizes the geometry of a parabolic shape to locate a focal point—where the sun’s rays concentrate to produce intense heat, similar to that supplied by a cooktop and effective for frying pans as well as pots.

When I was at SEI, for example, we used a unit constructed at a German technical college for world-wide distribution. This unit’s reflective panels and tubular steel created a highly practical cooker. The cooking surface was elevated directly in the focal point of its umbrella shape so that sunlight was focused from all directions when properly aligned.

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