DIY Solar Air Heater!
This video shows a new design for the making a DIY Solar Air Heater. This one is made with 7 lengths of 2×2 Steel “Drip Edge” Roof Flashing. Each of the 7 slats are dual-faceted and each create their own air channel. This gives a total of 7 closed air channels (and 6 open ones). The basics: the sun enters the unit thru the glass and strikes the 14 individual facets or faces of the absorbent black steel flashing. The metal is then quickly heated, and in turn, this heats the air inside the unit. the hot air is drawn out by using a small solar powered 12vdc case fan (located at the top). Note that the units’ fan is only activated in the presence of sunlight so it automatically shuts off when no heating is occurring. by using the 13 individual air inlets the air enters ‘equally distributed’ and is evenly heated as it passes over and under the hot steel slats. air temps were in the low 40’s (F) during testing. Output air temps varied but reached into the 160F+ range (topping out at 167.5 F (74C+) about noon time).
Lowest temp recorded was 110F (with sun just over horizon) and air temps of 135F were standard for mid-morning and late afternoon. Collector works great! One of the best. a note regarding insulation; i’ve made several different types of solar air heaters over the years and have come to the conclusion that insulating the unit is not necessary – as it does very little to increase the output temps. (that’s probably due to the fact that the air is only in the unit for a minute or two before it is vented out). Insulation is more important for something like a solar oven where you want the air to stay in there for hours and hours. If you still want to insulate, consider the back as the main area to focus on – since that is where the greatest surface area is (and therefore where the majority of the heat loss occurs).