Clothing Insulation and Thermal Comfort in Africa: Current Standards and Applicability

Background: The adoption of air conditioning (AC) is growing rapidly in developing countries across the world which puts a high burden on electricity distribution systems. This development is mostly driven by income growth and building design, but also due to increasing outdoor temperatures and to provide indoor thermal comfort. Current indoor thermal comfort standards are based on western clothing (in terms of the ASHRAE Standard 55 and ISO 7730). However, due to different clothing practices in regions such as Africa, providing comfortable indoor environments may differ significantly. For optimal design and achieving energy savings of AC systems, accounting for different clothing practices is fundamental. Methods: The research presented is based on a project aimed at the extension of the ASHRAE Standard 55 database to include non-western clothing. The paper focuses on the African clothing tested on thermal manikins. Three sets of female clothing and five sets of male clothing were measured. The ISO7730:2004 standard which uses the PMV/PPD indices was used to assess the optimal indoor temperature (assessed between 20-30 °C). The occupant was considered acclimatized with low activity (120 W), with an air velocity of 0.2 m/s, no additional heat radiation and a relative humidity of 50 %. Results and Conclusion: The optimal indoor temperature for both women (PMV: -0.09, PPD: 5 %) and men (PMV: 0.1, PPD: 5 %) was found to be 24 °C. Considering better ventilation and evaporation in African clothing the comfort temperatures could be even higher. In conclusion, sub-optimal indoor thermal conditions are being adopted in Africa resulting in lower indoor air temperatures than required, causing an unnecessary waste of energy from AC systems and affecting the thermal comfort of the occupants.