Natural cooling technologies for below 25 degrees
Hi Toby Last time I asked TSS for help on this it was for small drug stores in rural S Sudan. Now I am looking at 1000 to 2000m2 warehouse for medical and relief items in Palestine. This area get up to 38 degrees in the summer which is too hot for many medical and relief items. Do any of your panel of experts have experience in construction of warehouse for such areas that use natural cooling technologies to keep the interior at less than 25 degrees? Regards Pete
Yes, there are essentially two approaches to cooling in hot climates without the use of electricity. One is to access the constant subterranean temperature. This is hotter than ambient air temperature in winter and cooler than air temperature in summer. The top 3 metres of ground are usually in the range of 10 - 16 degrees C. A common technology for taking advantage of this stable regime is ground source heat pumps, but these obviously require an external electricity supply. Employing ground cooling using only ambient energy requires both excavation/ burial of cooling ducts and a means of drawing air through them into the space to be cooled. One useful approach to this could be a solar chimney - a pipe or vertical masonry chimney, which would be heated by solar heat during the daytime, creating an internal thermo-syphon which would draw air up from the bottom to the top. This would be connected to the top of the cooled space, allowing the cooled below-ground ducts to be connected at the bottom. The chimney would then draw air from the ducts, through the building.
The second (and possibly complementary) approach would be to use the phase-change or 'night storage' effect of heavy construction - a common aspect of vernacular architecture in hot climates. In this technique, key parts of the building constructed of heavy materials (masonry, rock, rammed earth, etc) are cooled by night-time ventilation and then used during the midday heat to absorb heat from the air inside the building.
Both these approaches require some thought about how best to move air through ducts and how to arrange these in relation to chimneys, massive walls, underground cooling areas, etc.
Hope this helps. Ask if you need more detail...
Shade netting is simple and light weight solution. Brise soleil....overhanging shades?
A second roof with air space between is usual. Mass construction of walls to control heat gain/loss....earth blocks? Stack vent with draw in via pipes buried in earth, or running through water and vents in roof. Ditto +ve & -ve air flow across the building.
That is a hell of a lot of drugs to keep cool in that space................is it necessary? Can it be stacked into a smaller space within the warehouse and away from dispensary?? Obvious, but sometimes the obvious works!
I am reminded of Adnams Brewery warehouse, where it is so well temperature controlled with thick walls and roof, that the back up AC has never been used.
NB. Multi foil insulation is expensive but very good, especially with the reflective surface.
This thread is public, all members of KnowledgePoint can read this page.