Solar Air Heating for Mobile Homes and Metal Outbuildings

The thermosiphon air panel is an easy, low-cost way to add solar air heating to your mobile home or metal outbuilding.

| January/February 1985

The integrated thermosiphon air panel (TAP for short) is a fresh approach to solar air heating — one that's perfectly suited to the 10 million or so folks who live in mobile homes and to owners of the countless metal-sided storage, industrial and commercial buildings around the world. By making use of the building itself as a part of the collector, the TAP keeps material costs down, simplifies construction and maintains a low visual profile. And because it relies on thermosiphoning to move air past the absorber, the TAP avoids the complexity and cost of an electrically driven fan.

Steven McCarney, the developer of the TAP, says the idea evolved after he'd installed several standard collectors on metal-sided buildings. In his words, "It seemed redundant to put a collector with a separate absorber and an insulated back on a building that already had those elements." Hence, Steve decided to use the building's own insulated wall as the collector's absorber. Now, longtime readers may recall that the integrated collector idea goes back a little ways (remember the Waterman solar setup in MOTHER NO. 48?). But, regardless of the origin, McCarney and his co-workers can take credit for researching and refining the scheme to the point where just about anybody can build a durable TAP that will pay back his or her investment in only a few years.

What It Takes to Build Your Thermosiphon Air Panel

What do you need to build your own TAP? The critical element, of course, is sunlight:

You need a metal-sided wall that faces within 25 degrees of south and that isn't shaded in the crucial winter months. You'll also need some hand tools, such as a drill, metal snips, screwdrivers, a caulking gun, a ¼ -inch nut driver and maybe a circular saw. Add to these items less than $100 worth of materials and a weekend's work, and you'll have solar heat flowing into your home.

How Big Should My Solar Air Collector Be?

A rule of thumb for solar air heaters is to allow 1 square foot of collector for every 10 square feet of floor area you wish to heat. (The room should first be caulked, weather-stripped and at least moderately insulated. Always take care of such energy-conserving fundamentals before adding solar heat.) Thus, a 180-square-foot room suggests an 18-square-foot collector. This, however, is only a rough estimate. The available wall space for mounting the collector and the limitation of standard tempered glass sizes (28-, 34- or 46-by-76-inch; 34 or 46-by-90-inch) will determine the actual dimensions of your collector.

Because the TAP relies on passive airflow to distribute the heat collected on its absorber, you'll get the best results by sizing the collector to warm the room directly adjacent to the wall on which it's mounted. Though heat will eventually be transferred to other rooms, oversizing the TAP to try to heat more than one room will make the first room too warm.

Rev. Dick Freeman_2
2/6/2009 11:08:21 AM

This is a simple type of construction that is able to save a constant amount on the heat bill, with a few changes and addition,s it can also be used to heat water.

10/11/2007 12:18:39 PM

I'm trying to look at the images galery and I printed the story but it did not print the Image on "TAP" The Sun. Can you help. Thanks Clair

10/11/2007 12:04:29 PM

I was trying to look at the image of the Storm Window Solor Panels Image Gallery but was unable. I tryed printing the story but the image did not print. Can you help. Thanks. Clair

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