Water condenser for a Madagascar solar desalination system

Current version of the desalination structure being used by Pano Rano in Madagascar. A similar version to this will continue to turn saltwater into vapor and the D-Lab team’s task is to condense this steam to obtain drinkable water. Photo: Tatirano Social Enterprise
Current version of the desalination structure being used by Pano Rano in Madagascar. A similar version to this will continue to turn saltwater into vapor and the D-Lab team’s task is to condense this steam to obtain drinkable water. Photo: Tatirano Social Enterprise

Initial research & development of a water condenser prototype which intakes and subsequently condenses H2O steam to produce clean drinking water, for use in Madagascar.

 

MIT D-Lab Class

D-Lab: Development

Student team

MIT students unless otherwise noted.

  • Sophia Chen, '24. Sophia is a MechE and Art/Design double major, planning to work in global health to address resource inequities and gender inequality after getting an MD/PhD.
  • Lilly Heilshorn, '25. Mechanical Engineering major from Pennsylvania who loves anything outdoors, especially scuba diving and sailing. Wants to concentrate in Sustainable Product Design and keep traveling!
  • Mako Irisumi, Wellesley '26. Computer Science major at Wellesley College, born and raised in Japan, who has a deep interest in the Department of Urban Studies and Planning (DUSP) courses at MIT and passionate about using AI to improve infrastructure systems.
  • Audrey Lorvo, '25. Economics major also minoring in Statistics and Data Science and in International Development, Audrey grew up in Latin America, Asia and Europe which fueled her interest in economic development and reducing inequality.
  • Luka Srsic, '25. Urban Planning major concentrating on Negotiations with a minor in Political Science. Passionate about Virtual Reality and Policing Policy.
  • Anson So, '26. Anson is a Computational Biology major with a particular interest in genomics and ecology of infectious diseases.
  • Thiago Veloso, '25. Computer Science major at MIT. I was born and raised in Brazil and I am very interested in STEM and Development, most importantly the use of technology in education.

Community partner 

  • Tatirano, Madagascar-based social enterprise
    • Harry Chaplin (Tatirano,harry@tatirano.org)
    • Karl Zimmermann (Univ. of British Columbia,karl.zimmermann@ubc.ca )
  • University of Antananarivo, L'Ecole Supérieure Polytechnique d'Antananarivo (ESPA)

Problem

Madagascar is one of the poorest countries in the world. With a population of 28.92 million, 75% of Madagascar’s population lives in poverty.1 The island is also facing a severe water crisis: only 34% of its population has access to safe water, and only 12.3% has access to basic sanitation services.2 This severe and urgent situation places Madagascar at the lower end of 76 developing countries concerning sanitation access–4th worst in sanitation and 3rd in water accessibility.2

In general, only 52% of the population has access to an improved water supply. However, the number can be misleading, since 83% of the population lives in rural areas, where the percentages are much more concerning–64% of the rural population uses unsafe water, divided between 23% using surface water and 41% relying on unimproved supply.³

Further worsening this issue is Madagascar’s vulnerability to droughts, specially the dry south of the island, which is severely affected by the lack of a robust sanitation system, and the widespread practice of open defecation. For that region, where the D-Lab team will be working, is particularly at the mercy of severe droughts. Even subterranean water, when it can be reached, is unfit for consumption as it contains high levels of salinity.

Marginalized groups are the most affected by Madagascar’s water crisis. In particular, women and children are held responsible for acquiring water for their households, and thus suffer the consequences of water scarcity, professionally and socially. Moreover, the time spent on acquiring water results in detraction from education and economic opportunities. Exorbitant prices lead to some parents having to take their children out of school to be able to afford water. Increased economic involvement of women in concert with improved water sources are imperative

Our project

To address this issue, the Madagascar-based social enterprise Tatirano has developed an innovative solution: the Pano Rano evaporation chamber. This device is capable of transforming seawater into pure steam through solar distillation. The goal of our D-lab project is to collect the steam produced by the Pano Rano chambers and condense it into clean drinking water. Our goal is to produce 15 liters of clean water per day. We are working with a budget limit of $500 to reconstruct these condensing chambers in Madagascar.

At a broader scale, Tatirano aims to use democratized water access as an opportunity to empower women in Madagascar. Tatirano specifically employs and trains women as part of their business model.

Technical solution

We are currently exploring two prototype designs: (1) a conical surface exchanger with fins and (2) a tubing network submerged in seawater. The conical surface exchanger is a two-part design, with a bucket and a cone-shaped piece of sheet metal. The bucket is attached to the steam source, or Pano Rano. The convex side of the cone-shaped metal is the condensing surface that the incoming steam contacts. Sea water is stored in the concave volume of the cone to cool the condensing surface. This serves a dual function to simultaneously pre-heat the sea water before it’s placed into the Pano Ranos for solar distillation.
As steam enters the bucket, it hits the cone-shaped metal surface and drips down to collect at the bottom of the bucket. To improve heat exchange and efficiency, fins were welded onto the convex side of the cone to increase the surface area.
For the conical surface exchanger, we are currently starting a testing phase to determine the amount of water that can be condensed over the course of 10 hours (a “functional day” in Madagascar).
The tubing condenser is based on similar condensers used in chemistry and distillation applications. The evaporated water is pushed through a coil of tubing submerged in a bucket of salt water. This allows for efficient heat exchange to condense the vapor into liquid (desalinated) water. It is being tested with various materials, looking for a lower cost way of utilizing this tried and true method.

Two sketches of a simple water desalinator.

Three photos showing the making of the condenser.
Caption: Graphic and photograph of initial prototype of condenser unit and testing setup. Use of a humidifier to model steam from evaporation chambers in the field. The prototype was made on a smaller scale than what will be constructed in Madagascar. Steam flows into the condenser unit through tubing, and subsequently condenses on the conical metal surface. This water is then collected at the bottom of the chamber for later consumption. Salt water contained in the concave volume of the cone further expedites heat transfer on the condensing surface. Image credits: MIT D-Lab Madagascar Team

References

  1. Madagascar - Human Development Reports. (n.d.-b). https://hdr.undp.org/sites/default/files/Country-Profiles/MPI/MDG.pdf
  2. World Bank Group. (2022, June 20). Madagascar: $220 million to improve basic water and sanitation services and supply. World Bank. https://www.worldbank.org/en/news/press-release/2022/06/20/madagascar-220-million-to-improve-basic-water-and-sanitation-services-and-supply#:~:text=Only%2054.4%25of%20the%20population,lowest%20access%20to%20basic%20sanitation.
  3. Madagascar Wash Investment Case, Executive Summary https://www.unicef.org/esa/sites/unicef.org.esa/files/2019-05/UNICEF-Madagascar-2019-WASH-Investment-Case-Executive-Summary.pdf

 


Contact

Libby Hsu, Lecturer; MIT D-Lab Associate Director of Academics