Validação do algoritmo do programa netuno para avaliação do potencial de economia de água potável e dimensionamento de reservatórios de sistemas de aproveitamento de água pluvial em edificações

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Rainwater use for non-potable purposes in buildings is a measure that provides the reduction of potable water demand and the minimization of problems related to availability of water resources. The efficiency of rainwater harvesting systems is affected mostly by the sizing of the storage cistern. The appropriate sizing is essential to avoid the superfluous room in the cistern when it is oversized; or insufficient room when it is undersized. The main objective of this research is to validate the algorithm of the Neptune computer programme, used to evaluate the potential for potable water savings and the sizing of cisterns for rainwater storage in buildings. Actual potable water and rainwater consumption, rainfall and variation of the water level in the cistern were obtained from an experimental house in Florianópolis. The monitoring of the rainwater harvesting system occurred in four different periods, totalling 196 days. Due to the variation of the house occupation, and also to the low water consumption verified in preliminary tests, it was necessary to increase the demand of rainwater, simulating the constant occupation of four residents. The daily demand of rainwater was taken as a percentage of the potable water demand, which was 150 litres per capita a day. Such a percentage was varied from 40 to 150% of the potable water demand, according to the monitored period. The volume corresponding to the rainwater demand was discarded daily. A modified version of the algorithm of Neptune was proposed, where the main difference in relation to the original version is the consideration of rainwater consumption before the rainfall. The study was based on computer simulations to evaluate the potential for potable water savings considering all data collected on site, considering different time intervals and the physical characteristics of the system. The results of the simulations were compared to the potable water savings obtained by using rainwater for non-potable purposes in the studied house. The average rainwater demands that were discarded were 279, 293, 607 and 624 litres a day, respectively, from the first to the fourth monitored period. The results of the study showed that the potential for potable water savings estimated by Neptune were identical to savings obtained in the house when there was enough rainwater in the cistern to fulfil the demand for rainwater. On the other hand, when there was not enough rainwater to supply the rainwater demand, absolute differences between Neptune results and the effective savings varied from 0.2 to 6.7%, for potable water savings ranging from 48.7 to 76.2%. The main conclusion obtained from the research is that the algorithm of the Neptune computer programme correctly predicts the potential for potable water savings by using rainwater in buildings.

ASSUNTO(S)

reservatorios simulação por computador algoritmos engenharia civil agua potavel - consumo - avaliação engenharia civil aguas pluviais - aproveitamento programas de computador - - validacao

ACESSO AO ARTIGO

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