Parameters Influencing the Sizing of Rainwater Tanks for Use in Houses

Abstract

Rainwater harvesting has been studied in different countries as a way of easing water availability problems and reducing potable water demand in buildings. The most important factor relating to the efficiency of a rainwater system is the correct sizing of the rainwater tank. Therefore, the objective of this article is to assess the influence of rainfall, roof area, number of residents, potable water demand and rainwater demand on rainwater tank sizing. The analysis was performed by using computer simulation and by considering daily rainfall data for three cities located in the state of São Paulo, Brazil. The roof areas considered were 50, 100, 200 and 400 m 2 ; the potable water demands were 50, 100, 150, 200, 250 and 300 l per capita per day; the rainwater demands were taken as a percentage of the potable water demand, i.e., 10% to 100% at increments of 10%; and the number of residents was two and four. Results indicated a wide variation of rainwater tank sizes for each city and also for each parameter. The main conclusion that can be made from the study is that rainwater tank sizing for houses must be performed for each specific situation, i.e., considering local rainfall, roof area, potable water demand, rainwater demand and number of residents. Therefore, sizing rainwater tanks according to local tradition is not recommended as it may incur low efficiency.

Potable Water Savings by Using Rainwater for Non-Potable Uses in Houses

“…Netuno was developed to estimate the potential for potable water savings for different rainwater tank capacities. More information about Netuno can be found in [18]; and information on its validation can be found in [19]. Advantages, disadvantages and limitations of Netuno can also be found in these works.…”

Exploring Rooftop Rainwater Harvesting Potential for Food Production in Urban Areas

“…In this view, several facets connected with RWHs and irrigation should be addressed, such as runoff water quality [63,69], tank water balance modelling, and performance [70][71][72] to define the suitable tank size by also taking into account other non-potable domestic water supply (e.g., WC flushing) and cost-efficiency analyses [68,73]. Guiding research efforts in this direction is of paramount importance, since water saving performance is highly affected by site-specific conditions such as the local rainfall pattern, the habits of the household dwellers, and the characteristics of the RWH and of the building [74].…”

Comparative Design and Cost Analysis of Cylindrical Storage Tanks with Different Head Types by Using COMPRESS

“…The first one defines relations for standard geometries: when it is used with the design stress, it leads to the minimum thickness of the vessel or component [9]. The thickness of the cylinder is only one part of the design.…”

“…Gong et al [8] performed a finite element analysis of open top tanks and explained that the structure parameters of top stiffening rings play a significant role on the failure of the tank. Ghisi [9] studied the parameters affecting the sizing of rainwater tanks for domestic use and recommended that regional assessment of rainwater tank sizing be carried out by taking into account local rainfall data, roof areas, number of residents, potable water demand, and rainwater demand. Tam et al [10] compared the cost of procurement, installation and operation of rainwater tanks to the benefits of the use of a rainwater tank in an empirical study to aid residential decisionmaking.…”