Optimal storage sizing for indoor arena rainwater harvesting Hydraulic simulation and economic assessment

“This study demonstrates a large roof (30,000 ni2) rainwater harvesting (RWH) system in an indoor arena by considering three water demand scenarios (toilet flushing, irrigation and combined demand) via hydraulic and economie assessments. The water sa ving efficiency (WSE) of the RWH system for each scenario was estimated by a simulation model using historica! daily rainfall data (1 968- 201 8). Depending on the water demand, the WSE was found to be independent of tank size when the tank size exceeded 1000 ni3. The results suggest that the WSE of the RWH system is highly influenced by water demand scenarios, and a storage capacity of 400-1000 m3 would be enough for the applications considered in this study. The economie analysis results funher showed that depending on the water demand, the RWH system with a rainwater storage capacity of between 100 and 600 m3 was more economically benefi cia! due to its positive cost saving values. The results also showed that depending on the water scenarios, the unit water cost between 0.37 and 0.40 f / ni3 was lower than the mains water cost (0.40 f / 1113). As a result, the use of d1e RWH system wid1 a tank between 400 and 600 1113 can be the most favourable range under the conditions considered in this study. Given the variations in water price, rainfall patterns and discount rates, the sensitivity analysis showed d1at water tariffs and discount rates play a significant role in reducing the unit water cost of the system, maintaining it lower than the mains water cost. A payback period analysis of the RWH system with a 600 1113 tank revealed d1at a 5% discount rate and a water price of 3 f / m3 would be enough to make the RWH system cost effective and that the capita! cost could be returned wirhin 10- 11 years. This study highlights the need for prelimina1y sizing of a rainwater tank and an economie analysis of a large rooftop RWH system to maximise the benefits.”

(Citation: Hofman, J.A.M.H., et al., – Optimal storage sizing for indoor arena rainwater harvesting Hydraulic simulation and economic assessment – Journal of Environmental Management 280(2021)111847 – DOI: 10.1016/j.jenvman.2020.111847 – (Open Access))

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