The development and improvement of solar equipment is a necessary step in the development of solar heating systems. One of the ways to develop solar air heaters is to use new materials for the production of solar absorbers. This expands the possibility of using nozzle and capillary-porous materials in contrast to liquid solar collectors. Development and research of air heating systems with equipment made of modern textile materials is relevant. For the manufacture of absorbers it is advisable to use textile materials. This will reduce the cost of solar collectors, as well as reduce their weight and capital costs. The absorber meets requirements for both solar thermal collectors and electric heaters: high absorption capacity of solar radiation; developed heat transfer surface; relevant physical properties: low mass, resistance to ultraviolet radiation, thermal resistance, low cost for cheaper solar system; sufficient electrical resistance. A combined solar-electric air heater has been developed, which combines two main elements of any solar system – a solar heat collector and an additional heat source, the absorber of which is made of carbon graphite knitted fabric. This reduces its cost and mass and allows them to be used on existing heating facilities without the construction of bulky supporting structures to accommodate solar fields. The combined solar-electric air heater can be used as an independent heat generator for heat supply systems. To use the proposed solar-electric air heater, it is necessary to heat its absorber with an electric current, so the material from which it is made must be electrically conductive, but have sufficient electrical resistance. The use of carbon-graphite knitted fabric allows the use the direct heating of the solar energy absorber by electric current due to the corresponding electrical characteristics. This article presents the results of an experimental study of the electrical resistivity of carbon-graphite knitted fabric. These studies allow determining the electrical power of the device regardless of the size of the device. The research results presented in the article can be used only for a certain type of carbon graphite knitted fabric.
Experimental research of electrical characteristics combined solar-electric air heater
