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Preliminary Field Test Results from a Photovoltaic Electrodialysis Brackish Water Desalination System in Rural India

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Preliminary Field Test Results from a Photovoltaic Electrodialysis Brackish Water Desalination System in Rural India Preliminary Field Test Results From a Photovoltaic Electrodialysis Brackish Water Desalination System in Rural India The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation He, Wei, Natasha C. Wright, Susan Amrose, Tonio Buonassisi, Ian Marius Peters, and Amos G. Winter. “Preliminary Field Test Results From a Photovoltaic Electrodialysis Brackish Water Desalination System in Rural India.” Proceedings of the ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 26-29 August , 2018, Quebec City, Quebec, Canada, ASME, 2018. © 2018 ASME As Published http://dx.doi.org/10.1115/DETC2018-86183 Publisher American Society of Mechanical Engineers Version Final published version Citable link http://hdl.handle.net/1721.1/120050 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. Proceedings of the ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference IDETC/CIE 2018 August 26-29, 2018, Quebec City, Quebec, Canada DETC2018-86183 PRELIMINARY FIELD TEST RESULTS FROM A PHOTOVOLTAIC ELECTRODIALYSIS BRACKISH WATER DESALINATION SYSTEM IN RURAL INDIA Wei He Natasha C. Wright Susan Amrose Massachusetts Institute of Massachusetts Institute of Massachusetts Institute of Technology Technology Technology Cambridge, MA, United States Cambridge, MA, United States Cambridge, MA, United States Tonio Buonassisi Ian Marius Peters Amos G. Winter, V Massachusetts Institute of Massachusetts Institute of Massachusetts Institute of Technology Technology Technology Cambridge, MA, United States Cambridge, MA, United States Cambridge, MA, United States ABSTRACT brackish water desalination has received renewed attention as a Brackish water desalination is crucial to meet basic drinking possible drinking water solution for India. water needs in rural India. Solar photovoltaic powered The most common desalination technology is reverse electrodialysis (PV-ED) has been justified as a more cost- osmosis (RO), with 60 – 90% of the market share depending on effective solution than the current dominant reverse osmosis location [5]. Tata Project Ltd. have installed and are maintaining approach for off-grid systems. This paper presents preliminary about 2,200 on-grid RO systems to meet daily drinking and results from an ongoing field pilot of a village-scale PV-ED cooking water needs across India, demonstrating that the system in Chelluru, which is a small village in South India. technology can operate in a village context. However, grid System performance is compared to predictions of a PV-ED electricity poses a number of challenges. In most villages, it is parametric model of local solar irradiance, ED system not reliable, usually providing electricity intermittently [6], and parameters, power systems parameters, water storage, and cost, also not prevalent. In 2011, only 55.3% of rural households used validating the model over a single-batch ED operation. An ~88% grid electricity for basic activities such as lighting [7]. On one “solar-to-treated water” conversion efficiency was achieved in a hand, brackish water desalination systems with oversized typical ED batch operation, using 2.47±0.27 kWh/m3 for production capability are designed to address poor grid quality, brackish desalination in the village. This paper also discusses the resulting in higher water cost. On the other hand, to compensate difficulties and local constraints encountered during the initial for poor grid access, diesel generators are often used, posing field testing and analyzes system performance in the context of additional environmental concerns. local constraints and availability. Including India, the rapid decrease in the cost of renewable energy generation [8] and the increased awareness of INTRODUCTION environmental sustainability have led many to explore This paper presents results from an ongoing field trial of a photovoltaic-RO (PV-RO) desalination in many countries which pilot village-scale solar powered electrodialysis brackish water have freshwater shortages [9, 10]. Thomson and Infield desalination system in rural India and preliminary validation of prototyped a 3 m3/day batteryless PV-RO system with a 2.4 kWp a systems-level model of energy flow. India is facing a severe PV panel in the UK, and its estimated lifecycle water cost was drinking water shortage. With a steadily increasing population £2.00/m3 [11]. Bilton et al. presented a generalized methodology that will reach an estimated 1.7 billion in 2050 [1], the water to evaluate the techno-economic feasibility of a small-scale PV- situation is expected to become even worse [2]. Groundwater RO system for desalinating water in a remote area [12]. They with salinities that exceed the acceptable salinity for drinking, concluded that a community-scale PV-RO system is more cost which is total dissolved salts (TDS) higher than 500 mg/L, effective than an equivalent diesel-based system and the underlies about 60% of India’s land area [3, 4]. As a result, transport of water in most remote locations [12]. 1 Copyright © 2018 ASME Downloaded From: https://proceedings.asmedigitalcollection.asme.org on 01/11/2019 Terms of Use: http://www.asme.org/about-asme/terms-of-use The abundance of solar irradiance in India and lack of grid data from 2010-2014, the average solar irradiance of Chelluru is access might suggest a straightforward PV-RO solution for about 5-6 kWh/m2/day. drinking water. However, Wright et al. found that the village- scale off-grid RO system is not the best option for brackish water THE PILOT PV-ED SYSTEM desalination in rural India [3]. For salinities commonly found in The objectives of the system design for Chelluru were to (1) rural India (TDS < 2000 mg/L), PV electrodialysis (PV-ED) minimize the system capital cost; and (2) maximize the water desalination has a much lower energy consumption, requiring recovery rate of brackish water desalination. The Chelluru less than 50% of the specific energy consumption (SEC) as RO system would also be an important case study to further improve to desalinate water to a final TDS of 350 mg/L [3]. This on the parametric design theory developed by Bian et al. [13], substantial reduction in energy consumption contributes to a and to help elucidate the technical, economic and social significant cost reduction in the off-grid power system. Bian et challenges of desalination in rural India. al. articulated a parametric theory between local solar irradiance, The PV-ED system in Chelluru was designed following the ED system parameters, power systems parameters including co-optimization methodology in [13], in which a cost- and number of batteries, and water storage, and was able to optimize performance-optimal PV-ED system using constant voltage and the capital system cost using the off-shelf components [13]. pumping power was designed using off-the-shelf components. Their preliminary analysis indicated a potential 42% cost The system design and operational parameters are listed in Table reduction compared to conventional design methods using 1. Solar irradiance data and temperature data of Chelluru from reasonable initial assumptions for a village-scale brackish water NSRDB for 2014 was used. desalination system in rural India [13]. Based on this optimized system design, an initial However, most of these studies are either theoretical studies configurable PV-ED system was built in Chelluru India in early or experimental studies in the lab. Very few systems are reported 2017. Figure 2 shows the installed system layout of the pilot PV- that have been tested in the field with actual brackish water ED system, demonstrating the ability of the system to reverse sources. To fill this significant gap, we installed and tested an operation through the ED stack and also the large amount of optimally designed PV-ED system in Chelluru, India, and product water storage acting as a buffer. This large buffer allows validated our system model to design co-optimal PV-ED systems the system to store water for cloudy days rather than increasing in India. The significance of the design model validation is to the number of batteries, reducing system cost. Figure 3 shows show the model’s ability to predict desalination behavior under the installed PV panels on the rooftop, the installed ED intermittent solar energy with battery storage, and the built membrane unit with piping, and the installed inverter and battery system’s ability to cost-optimally leverage these components to bank. meet the design goal of daily water production in a real-world A single hydraulic stage and single electrical stage ED condition. This paper describes the system design, validation of membrane unit was selected for the system design. The desired the energy flow model over a single ED batch, preliminary ED unit was modified from an available GE ED stack, model analysis of the system performance, and a discussion of lessons AQ3-1-2-50-35. As the original GE ED stack had two electrical learned during initial field testing. stages, the first electrical stage was not electrified and membranes were removed in the first stage to minimize the THE VILLAGE OF CHELLURU IN RURAL INDIA pressure loss. As a consequence, the modified ED stack had one Chelluru is an Indian village about 70km northeast of effective electrical stage and one “empty” electrical stage. In the Hyderabad with a population of approximately 2,000 people and future, the co-optimal system will use a single electrical stage a shortage of drinkable groundwater. The groundwater salinity is ED stack manufactured to the desired specifications. 1,300-1,500 mg/L, varying with the seasons. Currently, Chelluru’s drinking water needs are largely met by an on-grid Table 1 Chelluru PV-ED system design. RO brackish water desalination plant installed by Tata Projects Ltd., which has been used for eight years.
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