Paper presented to the 1st International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Kruger Park, 8-10 April 2002.
Currently, electrical resistance heaters are used to produce
most of the hot water in South Africa. Increasing electricity
tariffs make these devices very expensive. This paper
investigates the economic savings potential of using a
cogeneration system made of microturbines, heat pumps and
heat exchangers. Specifically the heating of water for large
residential units is investigated. Different economic parameters
are used to compare microturbine heat pump systems with
electrical resistance heaters, natural gas boilers and heat
pumps. For different main centres in South Africa, the amount
of hot water is determined where a cogeneration system is
economically more viable than other types of water heaters. It
has been concluded that the most important influence factor is
the electricity tariff. The higher the electricity tariff in a city,
the smaller the number of domestic consumers where a
cogeneration system becomes viable.
