Large scale solar water heating for Care Centre in KZN

By R Köstlin, Solardura


Published in:

Electricity+Control, May 2014 (pages 40-41)



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Compelled by the rising energy costs and the increasing need for reducing the carbon footprint, the Blessed Gérard Care Centre requested a Munich-based energy research institute to perform an energy audit of the centre. It was recommended that a large scale solar water heating system be installed.

A solar thermal system was configured for the Care Centre consisting of 61,7 m2 of solar collectors and 6 000 ℓ of back-up tanks. The SK500-ECO-AL solar collectors from SONNENKRAFT were specifically chosen for Mandeni because of their long lasting durability (Mediterranean version for coastal regions), their high efficiency (highly selective vacuum absorber coating) and the flexible mounting possibilities.

The 24 solar collectors are arranged on the North-West facing Inverted Box Rib (IBR) roof of the initial children’s home tract. The collectors are predicted to harvest a total of 53,46 MWh of energy each year from the sun. A stratified charging module (SLM120) transfers this energy from the collectors to the three stratified back-up tanks (PS2000E).

The charging module determines the energy available in the collectors and at the top and bottom of the tanks and optimises the energy transfer accordingly by circulating the hot water either to the top or the bottom of the backup tanks. A non-toxic, bio-degradable glycol-water mixture is used as heat transfer fluid in the collectors to minimise corrosion and optimise the heat transfer.


Take note

  • Particular solar collectors were selected for Mandeni because of their durability.
  • The solar collectors are predicted to harvest a total of 53,46 MWh of energy each year.
  • The solar water system is predicted to reduce CO2 emissions by as much as 7 580 kg per annum.