Optimization Of Rainwater Storage Tanks For Building (Case Study: Guilan_Rasht)

Rasht is one of the richest cities in rainfall in Iran, and because of collecting rain from the roof of the buildings a considerable amount of water can be stored, then designing and implementing of rainwater collection systems in Rasht can collect and save a significant amount of rainwater for uses like: green-space irrigation or Non-drinkable usages as whole. The catchment bank (rainwater storage bank) is the most important and expensive component of rainwater harvesting system (RWH) implementation on the roof of residential buildings. The reliability of these storage banks was estimated between 100% and 81% in three years of wetness, drought and normal index. The demand amount of this research is considered equal to the water needed for the irrigation of the cultivated grass in the green space of each building in the hot seasons. Then, we have estimated the optimum volume of storage bank using mixed integer linear programming method in LINGO.17 software for each of the buildings considering the expected reliability coefficient of the storage banks (70, 80 and 90%). These volumes are between 1.4 and 12.7 cubic meters in three years of wetness, drought and normal index with different reliabilities. Finally, we have estimated the storage bank volume of each demand for one of the roofs in different demands and the results were calculated between 0.55 and 5.27 cubic meters.