Agricultural wastes/ residues

Namibia is a Semi-Arid Zone where the temperatures are high with an average of
300 days of sunshine annually. Most of the commonly used building insulations are
made out of conventional materials which are petrochemical based substances that
contain toxic substances which are harmful to the environment. This study aimed at
comparing thermal efficiency of residential buildings of varying designs using
material from Agricultural residues and marble dust in Namibia.
Three prototype Rigs, with varying compositions were designed and built using
standard building procedures. Rig A (TAR 1) with 150 mm thick internal and external
walls; made of standard bricks of 7 MPa, insulated with compacted mixture
containing 20% (wt.) Maize, 10 % (wt.) Millet, 30% (wt.) Rice and 40% (wt.), 30%
(wt.) Cow dung; Rig B (Tamb2) 40% (wt.) with Maize, 30% (wt.), Millet, 10% (wt.),
20% (wt.), 20%wt. Marble dust and C (TNo3) that serve has control rig. Outside and
inside temperatures of the Rigs were monitored during the warm (September 2017 -
March 2018) and cold (April to August – 2018) seasons. Temperature and humidity
sensors installed at critical positions in the interior of the building, were connected to
symmetron data logger.
Results of the three design concepts revealed that TAR 1 (Rig A) attained
maximum and minimum temperatures of 24.40C and 14.80C, and humidity of 26.4%
during winter and 29.60C and 19.30C during summer with average humidity of
21.1%. Tamb2 (Rig B) recorded maximum and minimum temperature of 31.220C and
18.70C during summer with a relative humidity of 20.3%. During winter Rig B
attained average temperature of 22.600C. Furthermore, Rig C (TN03) recorded 32.220C and 21.700C in summer and winter respectively. From the results it can be
deduced that Rig A (TAR 1) with compositions of 20% (wt.) Maize, 10 % (wt.) Millet,
30% (wt.) Rice and 40% (wt.), 30% (wt.) Cow dung; had the best performance.