A low cost thermal energy absorber for rural Africa applications: isolation of high pressure and low pressure through heat exchanging

摘要

A low-cost heat exchanger system was developed that enable the realization of high pressure, low pressure isolated solar water heating systems in Africa. Africa countries are mostly located mid equatorial and has superfluous resources of solar and thermal energy. The design comprised of a copper coil based heat exchange system that can replace the normal heating element and thermostat in a conventional household geyser. The circulation in the system is performed by a small separate photovoltaic panel and circulation pump. The exchanger allows for isolation of the high pressure and low pressure sections of a normal household geyser system and enable the utilization of very large, low cost solar heat absorber platforms. This feature remarkably increasing the heat collection capacity of the system. An integrated switch allows the system to alternate between conventional electrical heating and solar water heating, according to prevailing weather conditions. A smart sensor system monitor absorber and ambient temperatures continuously, and controls switch on times and circulation rates according to prevailing weather conditions, and in order to optimize thermal energy collection. The system can be installed at approximately 10 000-12 000 SA Rand. Calculations show that the system can provide hot water to a household in South Africa at approximately 0. 12 SA rand per kWh, implying a saving to current customer that uses grid electricity at approximately R600 per month (weather depending). The accumulated saving to the household owner is of the order of 200 000 SA Rand over a ten year lifetime period for the product. The system offers numerous new business opportunities and job creation opportunities in South Africa. It is believed that the technology can be supplied and products can be provided to other international countries outside of South Africa. In this case the international countries can draw advantage from the technology as developed in South Africa, and can import products at reduced (very low costs) drawing on the advantageous of an extreme favorable exchange rates, reduced import levies, while providing dire job opportunities in an developing African countries.