Life cycle assessment of a rainwater harvesting system compared with an AC condensate harvesting system

Abstract

This study presents a life cycle assessment (LCA) of a rainwater harvesting (RWH) system and an air-conditioning condensate harvesting (ACH) system for non-potable water reuse. U.S. commercial buildings were reviewed to design rooftop RWH and ACH systems for one to multi-story buildings’ non-potable water demand. A life cycle inventory was compiled from the U.S. EPA’s database. Nine scenarios were analyzed, including baseline RWH system, ACH system, and combinations of the two systems adapted to 4-story and 19-story commercial buildings in San Francisco and a 4-story building in Washington, DC. Normalization of 11 life cycle impact assessment categories showed that RWH systems in 4-story buildings at both locations outperformed ACH systems (45–80% of ACH impacts) except equivalent in Evaporative Water Consumption. However, San Francisco’s ACH system in 19-story building outperformed the RWH system (51–83% of RWH impacts) due to the larger volume of ACH collection, except equivalent in Evaporative Water Consumption. For all three buildings, the combined system preformed equivalently to the better-performing option (≤4–8% impact difference compared to the maximum system). Sensitivity analysis of the volume of water supply and building occupancy showed impact-specific results. Local climatic conditions, rainfall, humidity, water collections and demands are important when designing building-scale RWH and ACH systems. LCA models are transferrable to other locations with variable climatic conditions for decision-making when developing and implementing on-site non-potable water systems.

Economic and Environmental Assessment of Two Different Rain Water Harvesting Systems for Agriculture

“…It is clear that irrigation might tip the scale towards a less sustainable scenario as observed by Stephenson et al (2010) [23]. Some authors have evaluated the emissions generated by water harvesting systems and the related costs [32], even if the majority of the studies focused on the impact of RWH systems in urban environment [18,[43][44][45][46].…”

Análise da viabilidade econômica do aproveitamento de água de chuva para edificações verticais do tipo residencial na Cidade de João Pessoa Estado da Paraíba

“…A prática de captação de água da chuva, recentemente, tem sido usada em países com climas úmidos, principalmente com o interesse em aumentar as práticas de construção sustentável que apoiam o uso inteligente da água, especialmente para fins não potáveis (Cardoso et al 2020). São exemplos de países que têm financiamento para a construção de sistemas de captação de águas pluviais: Austrália, África do Sul, Estados Unidos, Itália, Espanha e Portugal (Domènech & Saurí, 2011;Ward et al, 2012;Thomas et al, 2014;Hajani & Rahman, 2014;Silva et al, 2015;Ghimire et al, 2019).…”

Urban stormwater characterization, control, and treatment

“…Researchers proposed a rebate on capital costs and raising the water price to make rainwater harvesting a viable option in Brunei (Abas & Mahlia, 2019). Ghimire et al (2019) compared the economic feasibility and productivity of rainwater harvesting systems to air conditioning condensate harvesting (ACH) in San Francisco and Washington D.C., United States. Using a lifecycle assessment approach, they were able to determine that rainwater harvesting outperformed ACH on four-story buildings, ACH outperformed RWH on taller buildings, and a combined system was the most effective (Ghimire et al, 2019).…”