DeSoto Solar
| |
| This page shows installation of two Type 3 passive solar heating panels in a self-heating workshop built about twenty miles south of DeSoto in Madison County, Iowa, USA (41.264885,-93.988130). |
|
Each panel is eight feet wide and six feet tall, and consists of about three hundred custom cut / machined / formed parts (there's more here than meets the eye). The wooden parts are all mortise and tenon, and are cut under computer control to ensure precision fit and long life. |
| The panels were hauled to the customer's building site and the four-man construction crew set the panels into a pair of 8' ½" x 6' ½" openings and shimmed/screwed the panels in place after making sure that they were plumb and level. This entire operation took about 45 minutes from start to finish, but that may have been because they'd never seen a solar heating panel before. |
|
Here's a closer look at the framing of the rough opening. It's all 2"x6" southern yellow pine lumber. If you look closely at the left (west) edge of the panel, you can see the shims between the rough opening framing and the panel body. The shims on the other three sides can't be seen in this photo. |
| For anyone who's been wondering what a "shim" is, here's a photo of a pair of shims - thin wooden wedges inserted from opposite sides of the wall until they fit tightly together. Once they're tight, a screw is driven through the frame member, through the shims, and into the outer wall of the solar panel. The screws and the shims fix the position of the panel permanently. Once the screws have been driven, the excess length of each shim is removed and discarded. |
| The gap between the panel and the framing members is then filled with foam or fiberglass insulation to prevent heat loss. Here you can see the shims at the lower east corner of one of the newly-installed panels. |
| By noon the next day, the construction crew had applied steel siding to the outside and plywood paneling to the inside of the entire south wall. In this photo they're working on the roof trim - and you can see that the solar panels and the window look a bit more as if they might actually belong where they are. |
| When the construction crew paneled the inside south wall, they drilled a ½" hole in the approximate center of each of the solar panel vents. I used a router with a 3/8" flush trim bit to cut the eight intake holes near the floor and the eight narrow discharge vents at the top of the panels. |
| I took this photo just after I'd routed the vent holes. Here's a close look at the freshly-cut cold air intake vents. |
|
Although I'd tried to talk the customer into adding a third solar heating panel in the center of the south wall, he insisted that he'd rather have a window he could see through. After taking my first look through that window, I understood why. |
|
Here's a close look at the freshly-cut hot air discharge vents. The construction crew expressed amazement at the temperature and force of the panel airflow - they were surprised that the air could be moved so rapidly without blowers. |
| A couple of days later I stopped by to check operation of the collector and took a few more photos. The shop building is finished and the concrete floor has been poured. |
| An indoor view of the east panel. The inside looks much different with a concrete floor in place. |
| Indoor view of the south wall. Note the ceiling fan that will be used in winter to move the warm air near the ceiling down to warm the concrete floor. This will provide more even heating and extend the daytime comfort level into the evening. |
|
Indoor view including the west wall. The small wall-mounted heater will provide make-up heat after the overhead door has been opened in wintertime. 2010 update: The heater turned out not to be needed – with the thermostat set all the way down, the heater never turned on, and the concrete slab (floor) stores enough heat to keep the building warm for several weeks. The downside is that the owner's wife stores her houseplants in his shop during the winter. |
| Here you can see the overhead door on the east side of the building that is opened at the beginning and end of every day. |
| I designed and built these two eight-foot by six-foot passive solar heating panels for installation in 2007. They have been adequate to maintain the indoor temperature above 65°F/18°C since that time – even though outdoor temperatures in winter dropped below -20°F/-29°C and even though the nine-foot by nine-foot overhead door has been opened every morning and every evening. Before the end of 2009 the panels had saved more than their purchase price in fuel costs and the owner expects that the future savings will exceed the original cost of the entire structure. | |
| In 2010 the panel design was modified to include a stainless steel skin covering exposed wood surfaces to extend panel service life (in non-salt environments) beyond 100 years. |
|
| |
