A Solar Furnace - Anyone?

Yesterday a bright yellow plastic bag with a fuel delivery ticket inside hanging on her mailbox flag announced that my neighbor just received 389 gallons of #2 fuel oil. Her farmhouse is empty because she now lives in an assisted living facility but to prevent mold issues and keep toilets, traps and pipes from freezing she has the thermostat set at 50 degrees. I’ve been looking after her place for years as her husband’s health failed, then passed away and her own health deteriorated. Later this spring her home that sits on 57 acres and where her family lived for 40 years is under contract for sale.

Fuel Oil Delivery Ticket: 388.8 gallons 10-24-14 to 1-19-15

The coming deadline gives me almost three months to cut dead or dying trees along fencerows and gather fallen branches that make good firewood. I’ll miss checking the indoor temperature every day by glancing, from outside, at the large thermometer hanging inside her kitchen window. I’m usually on skis chasing my daughter who is much faster than I and we always include this point in our varied routes that cover two or three miles. The snow melted this past weekend so we’re covering rougher terrain on foot, looking for signs of owls, fox and coyotes because they are unusual compared to mice, rabbits and the four dozen deer we saw yesterday.

So far this heating season it’s taken over a ton and a half of fuel oil to keep her farmhouse from freezing. It would have taken more to maintain 65 degrees. Since we’re midway through the heating season, it’ll take more than 3 tons of fossil oil costing more than $2,500. Carbon dioxide contribution to the atmosphere? 17,400 pounds, almost nine tons! Could solar do better? Not without a lot of progress that no one seems to be addressing.

The sun often shines 15 hours during a day in June when it’s warm but energy is needed for only for heating water for washing and showers. Because upstate New York is downwind from the great lakes, we get very little sun during November and December when home heating issues become serious. Burning wood for heat is popular and most neighbors have a parlor stove or fireplace insert to reduce the cost of heating with electricity, propane or oil. In rural New York there are no natural gas lines so we don’t have that option.

One carbon neutral approach for using high performance solar collectors would be to combine them with furnaces that burn either wood pellets or cordwood. Pellets can be delivered in bulk and ignited/fed automatically so tasks become adjusting the thermostat and emptying ash.  Wood chunks have to be created by cutting trees, hauling logs and branches, and reducing them to sizes that are easy to handle. And they have to be strategically loaded into the firebox filled with coals. A cold firebox requires the extra work of lighting kindling. A solar collector could supplement these burners so keeping warm would require only half the wood. In our case we would have to process only 12,000 pounds of wood instead of 12 tons. For six months solar would provide both hot water and heat: no need to start fires. But we’d have to handle wood in bad weather during the coldest months, a process that I’ve enjoyed for decades. It keeps me active and often exposed to awesome starry skies, meteors and northern lights that I would not see if I stayed indoors.

Combining a Solar Collector with an Outdoor Wood Furnace

We’re developing solar technology so folks in rural communities can fabricate components, assemble solar collectors and use them for 30 years heating water and homes.  These solar collectors still need appliances like air conditioners, clothes driers, cooking appliances or thermochemical reformers so that they utilize the abundant energy available at temperatures up to 1,000 degrees during the summer. Intensifying sunlight 1,000 times even here in the cloudy northeast, these high performance solar collectors readily collect 80% of the energy available and return money invested in an installation without subsidies in five years and energy invested in the equipment in five months. Not using sunlight available during the summer extends these paybacks. These costs do not include backup heating equipment needed to keep warm when the sun doesn’t shine, stored heat has cooled down and it’s getting cold. Homes already have hot water and central heating so these can fill in when there is not enough sunlight.