Upgrading the building envelope to reduce cooling loads

Cooling buildings in summer is one of the main environmental problems for architects and builders in many Middle East countries. The weather during that period reaches peaks of more than 50 °C in some. Compressor air conditioners can solve the problem but they put a heavy strain on the electricity load. Evaporative coolers consume far less but sometimes do not lower the temperature enough for comfortable living. A procedure was tested for this research to combine the best of both by employing evaporative systems to cool only the structural envelope. A test building was modified in Baghdad, Iraq to test the system. The roof was cooled using a pool in a tunnel like compartment. The latter was ventilated by a small fan. The walls enclosed a 10 cm cavity. Cooled air from a small evaporative cooler was pumped into it. The test results showed a drop in interior temperature of more than 10 °C to an average of 31.76 °C. This system allows a compressor air conditioner to be used to further cool the interior. Calculations revealed that after using it to reduce temperatures to comfortable levels, the cooling load was less by up to 88% compared to untreated rooms.

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► A single room building has its walls and roof modified.
► Both are then cooled using cheap evaporative systems.
► Temperatures are measured with and without cooling over several days.
► Thermal comfort levels and cooling loads are calculated.
► Computer simulations show that the system reduces cooling load significantly.