Análise da influência do uso de materiais fototérmicos na eficiência de dessalizadores solar tipo pirâmide assimétrica

Abstract

The Brazilian Northeast has a good development potential for the exploitation of solar energy, in this way, solar still becomes an alternative to potabilize these brackish waters. In this research, a thermal study of a modified asymmetric pyramid solar desalinator was carried out in order to obtain treated water with potability standards for human consumption. Three pyramid-type solar still of equal dimensions were designed and built, where sensible heat storage material trays were placed in two solar still, in order to increase the productivity of desalinated water. In the first desalinator (D1) granite was placed, in the second (D2) ceramic tile. The third desalinator was used for comparison purposes. Raw water was collected at Sítio Furnas, in the municipality of Queimadas - PB, and characterized, before and after the desalination process, by the following physicochemical analyses: pH, electrical conductivity, chlorides, hardness, alkalinity, turbidity, sodium and color. For thermal analysis, the temperatures in the tray, on the inner and outer glass of the solar still, ambient temperature and solar radiation were measured. It is concluded that the SHS materials after being painted black that absorbed more heat were granite and tile. In general, the production of desalinated water and the thermal efficiency are directly related to the incidence of solar radiation. The highest production with the use of photothermal materials was with 1,0 cm of water thickness and using the tile, with a value of 2,500 mL.m-2 for D2. The use of photothermal materials has been proven to increase water production in desalination plants. So, D3 showed a water production 25% higher than D1 for a water thickness of 3 cm. The use of granite and tile in the solar still resulted in an efficiency increase of 126% and 63%. After the desalination process, all the physical-chemical parameters were reduced, in accordance with the standards of potability of water for human consumption, according to the Ordinance of the Ministry of Health in force in the country. Therefore, it was proven that the prototype developed was viable and efficient for use in the Brazilian semiarid region to obtain drinking water.