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RedR TSS

I had a look but my records are not that good as about the time I changed computer but I can remember the basics proposed for East Timor. Dave Hodgson is more an expert but here are the basics that I recall:

In most parts of the world the ground temperature does not change year round at about 1.5 to 2 m down and is fairly constant; the idea then is to draw or push air from the bottom of a clean hole / space about that depth.

In the Timor case I remember we needed a stable temperature in an area with an unreliable electricity supply so the answer was to use a wind cowl (a pivoting intake or wind scoop aligning to the prevailing breeze) to create an air flow air via a large duct which discharged at the bottom of the pit. In the middle east wind scoops (malquaf or badgir) are used to channel air from the higher levels down into living areas and the same principles can apply. From there the air would either flow, or could be drawn by a low power (possibly solar) fan up into the building.

This was proposed by a number of adherents in the 1970s, the one I recall was in Ken Kern's "The Owner Built Home". I recall in that book he also referred to a German patent that used crates of gravel placed in cellars to increase the efficiency and heat mass. Again the principle is fairly simple that the air must flow around the gravel and be in contact with it so a uniform rather than graded gravel would be desirable.

In another book "The Natural House Book" by David Pearson, he provides comparative figures for Australian built earth covered homes indicating the significant temperature stability below ground - as I recall in one example about 12 Deg C fluctuation internally while outside temperatures varied from subzero to mid forties.

The ceiling of the warehouse needs to be ventilated (with screens against bugs and snakes) to allow the hot air to rise and ventilate, thus drawing air from the pit.

In a somewhat different application traditional Khmer houses do this... the tiled roof is unsealed allowing hot air to flow out. The slatted floors which are raised above ground allow any breeze to enter, and even draw air in as the hot air rises and escapes through the vents, such as when two to three families live as an extended family in a large room; the air is drawn through the floor and vented through the roof. This air movement is also effective at minimising mosquito nuisance ( they do not like moving air).

My suggestion would be to use the stable temperature below ground, increase the heat / cool mass and draw or flow the cooled air into the building (may be low power solar fan, heat funnels may work)

I did two missions in South Sudan and my impression there was of considerable heat and quite a lot of sun, plus rusted corrugated iron roofs. I would try to stay away from CGI roof as it will rust and the rusting will drastically increase the heat. If sheeting is necessary then a ventilated roof is commonly used both there (and here in Indochina) where roof sheets are overlapped to be weather proof but have good ventilation near the apex (with a bug screen). I also noticed local people build with mud and "reed". The reed is actually a bamboo genus. Planting bamboo around the structure would be a quick growing and effective way of cooling or channelling breezes with some innovation.

Regards, Chris Nixon