Sarah Ann Hall

Reporting on writing in progress or, more probably, not; practising flash fiction.

Excuse#14 The solar air heater

with 2 comments

Sitting at a craft fair is probably not the best place to write my blog. I should be concentrating on selling jewellery. But, as there hasn’t been a rush since the doors opened at 11am, and as I brought one set of wool and knitting needles but the wrong pattern, I’ve not got anything to keep my hands busy. And so, to the solar air heater….

An insulated plywood box.

The design and construction of a solar air heater is, in theory simple, quick and cheap. Typing in ‘beer can heater’ on youtube will yield a plethora of designs. Hubby came up with his own. This didn’t present any problems but it does seem to have taken an age to build.

Hubby started by constructing a box frame from exterior-grade plywood, which I painted while he was living it up in Las Vegas. The box was lined with foam insulation (to stop any heat loss) and this was lined with foil and sprayed black.

Hose fitted and being sprayed



Hose was wound from an inlet hole (drilled) on one side to an exit hole (drilled ) on the other. This process was responsible for a slight delay as we had only ordered half the amount of hose we needed and had to wait for some more to come through the post. After being fixed, the hose too was sprayed with matt black heatproof paint. And then we fitted polycarbonate sheet to close the box.

It all sounds so simple, but I’ve forgotten the boxes to house the fans and the boxes that cover the roof vents, which have ended up looking like miniature pill-boxes. There always seemed something else we needed  to do.

And the point of all this? During sunny days in spring and autumn the air will heat up and be fanned into the boat negating the need to light a fire during the cold and clear nights. And in the winter, again on sunny days, hopefully enough hot air will blow in during the day that we won’t need to light the fire as early, thereby saving fuel. Well, that’s the theory. On the first day of operation, the heater sucked in fresh air at a temperature of 17°C and heated it up to 96°C, which was then pumped into the boat, so we live in hope.

On the roof, heating the air.

Inside, the digital thermostat. Now that's what I call hot air.


Written by Sarah Ann

March 31, 2012 at 5:16 pm

2 Responses

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  1. Does the air get into the heater by itself or is there a mechanism to cause this?


    November 12, 2012 at 9:23 am

    • Hi Abraham,

      The air enters on its own and, as it heats up, rises, so sets up a circulatory system. That’s the theory, but to help it along we installed two computer fans – one to suck cold air out (on the left) and one to push the hot air in (on the right).

      We discontinued use in the summer and have since taken the heater down for maintenance (re-painting). It’s currently sitting on the roof awaiting re-wiring so I’ll have to get back to you on the success/ not of the venture. The theory was good, we’re just not convinced yet on the application.

      Sarah Ann

      November 12, 2012 at 8:57 pm

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