Optimizing rainwater harvesting systems as an innovative approach to saving energy in hilly communities

Self Cite

Current centralized urban water supply depends largely on energy consumption, creating critical water-energy challenge especially for many rapid growing Asian cities. In this context, harvesting rooftop rainwater for non-potable use has enormous potential to ease the worsening water-energy issue. For this, we propose a geographic information system (GIS)-simulation-based design system (GSBDS) to explore how rainwater harvesting systems (RWHSs) can be systematically and cost-effectively designed as an innovative water-energy conservation scheme on a city scale. This GSBDS integrated a rainfall data base, water balance model, spatial technologies, energy-saving investigation, and economic feasibility analysis based on a case study of eight communities in the Taipei metropolitan area, Taiwan. Addressing both the temporal and spatial variations in rainfall, the GSBDS enhanced the broad application of RWHS evaluations. The results indicate that the scheme is feasible based on the optimal design when both water and energy-savings are evaluated. RWHSs were observed to be cost-effective and facilitated 21.6% domestic water-use savings, and 138.6 (kWh/year-family) energy-savings. Furthermore, the cost of per unit-energy-saving is lower than that from solar PV systems in 85% of the RWHS settings. Hence, RWHSs not only enable water-savings, but are also an alternative OPEN ACCESSWater 2015, 7 6286 renewable energy-saving approach that can address the water-energy dilemma caused by rapid urbanization.

Section: Water Quality Issue and The Cost Of Rwhssmentioning

confidence: 99%

Designing Rainwater Harvesting Systems Cost-Effectively in a Urban Water-Energy Saving Scheme by Using a GIS-Simulation Based Design System

Chiu

Tsai

Chiang

2015

Self Cite

“…According to [2,3,12,20], the potable water demand varies between 45 and 209 L per capita/day around the world. Thus, the potable water demands used in the simulations were 50, 100, 150, 200 and 250 L per capita/day.…”

Section: Potable Water Demandmentioning

confidence: 99%

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

Souza

Ghisi

2012

Abstract:The objective of this study is to assess the potential for potable water savings by using rainwater as well as the sizing of rainwater tanks in houses in some cities in the world. Daily rainfall data for thirteen cities located in different countries were used. Different catchment areas, number of residents, potable and rainwater demands were considered in order to assess their impact on the potential for potable water savings and sizing of rainwater tanks. The analysis was performed using the Netuno computer program. The results showed that the greatest potential for potable water savings is obtained in cities where there is constant rainfall, which does not always mean high annual average rainfall. Cities with well-defined periods of drought require larger tank capacities. Overall, it was observed that all parameters (catchment area, number of residents, potable and rainwater demands, and rainfall) influence the sizing of the tank for rainwater storage.

“…Liaw and Chiang (2014) [2] developed a regional-level and dimensionless analysis for designing a domestic RWHS. Moreover, regarding design using economic and dimensionless analysis-based optimization approach, Chiu et al (2009) [3] optimized the most cost-effective rainwater tank volumes for different dwelling types using marginal analysis. Campisano and Modica (2012) [4] developed a dimensionless methodology for the optimal design of domestic RWHS.…”

Section: Introductionmentioning

confidence: 99%

Optimal Spatial Design of Capacity and Quantity of Rainwater Harvesting Systems for Urban Flood Mitigation

Huang

Hsu

Wei

et al. 2015

This study adopts rainwater harvesting systems (RWHS) into a stormwater runoff management model (SWMM) for the spatial design of capacities and quantities of rain barrel for urban flood mitigation. A simulation-optimization model is proposed for effectively identifying the optimal design. First of all, we particularly classified the characteristic zonal subregions for spatial design by using fuzzy C-means clustering with the investigated data of urban roof, land use and drainage system. In the simulation method, a series of regular spatial arrangements specification are designed by using statistical quartiles analysis for rooftop area and rainfall frequency analysis; accordingly, the corresponding reduced flooding circumstances can be simulated by SWMM. Moreover, the most effective solution for the simulation method is identified from the calculated net benefit, which is equivalent to the subtraction of the facility cost from the decreased inundation loss. It serves as the initially identified solution for the optimization model. In the optimization method, backpropagation neural network (BPNN) are first applied for developing a water level simulation model of urban drainage systems to substitute for SWMM to conform to newly considered interdisciplinary multi-objective optimization model, and a tabu search-based algorithm is used with the embedded BPNN-based SWMM to optimize the planning solution. The developed method is applied to the Zhong-He District, Taiwan. Results demonstrate that the application of tabu search and the BPNN-based simulation model into OPEN ACCESSWater 2015, 7 5174 the optimization model can effectively, accurately and fast search optimal design considering economic net benefit. Furthermore, the optimized spatial rain barrel design could reduce 72% of inundation losses according to the simulated flood events.