Performance of solar water heating systems in Botswana

There is plenty of solar energy in tropical countries that make solar thermal applications attractive in these regions. For example, in Botswana, the government, the housing corporation and the mining companies have installed over 10 000 solar water-heating units. However, most of the first generation units did not supply adequate hot water when required. It is also common to find units abandoned or the users uninterested in the condition and the energy contributions of the solar water heaters. Consequently this paper presents the results of an on-going investigation to determine the technical performance of solar water heaters in Botswana. The study consisted of an extensive questionnaire survey administered to system owners and users in 5 different residential zones in Gaborone. Various technical problems were identified, categorized and discussed. Lack of standards and regulations to monitor and control the manufacture, installation and performance of solar heating systems seem to be a major source of problems.