Evaporative Cooling for Fruit and Vegetable Preservation in Turkana

This is our second experimental setup to test different structures and configurations for the cooler. All of the designs use locally available materials so that people could make the cooler themselves. Photo: MIT D-Lab/Christin Tang
This is our second experimental setup to test different structures and configurations for the cooler. All of the designs use locally available materials so that people could make the cooler themselves. Photo: MIT D-Lab/Christin Tang
MIT D-Lab

 

Hello! We are Ava Dijstelbloem ‘25 and Christine Tang ‘25, from MIT D-Lab, and this summer we are in Kenya working with the Turkana Basin Institute and D-Lab principal investigator, Eric Verploegen, to research evaporative cooling as a means of post harvest fruit and vegetable storage.

In regions of the world where access to food preservation methods is limited, up to 50% of produce is lost during transport or at markets before it ever reaches households. In addition, many households are unable to preserve fresh produce for longer periods before it spoils. This project aims to provide an affordable and locally accessible solution for communities that lack access to electricity and vegetable preservation methods. 

Understanding the local context

Since arriving in Turkana three weeks ago, we have conducted interviews with vegetable vendors in Lodwar and Kerio to better understand the local supply chain and the need for cold storage in the Turkana region. We also spoke with a local farmer about her farming practices and how she is currently able to cool her vegetables post harvest. Both the market vendors and farmers mentioned that a significant amount of produce and income is lost each week due to spoilage. One market vendor reports losing 25-50% of her produce weekly. Through these interviews, we also learned that many people in the Turkana region already have an understanding of evaporative cooling and use this as a method to cool produce by sprinkling water or placing wet jutesack over produce in the evenings. 

A farm in Kenya
We interviewed a woman at this farm to learn how farmers store their fruits and vegetables and transport them to the market. Photo: MIT D-Lab/Christine Tang

Experimenting with different designs 

In addition to conducting interviews, we have started an initial round of experiments to test the effectiveness of various materials and configurations for evaporative cooling. Our first experiment tests bulk absorber materials that are used to store water and allow for evaporation throughout the day. These bulk absorbers include: sand, charcoal, and charcoal briquettes. We sewed each material into a jute sack blanket which was placed on top of identical plastic buckets.

This is our first experimental setup that tests how well sand, charcoal, and jute sack are all effective in retaining water for evaporation. 
This is our first experimental setup that tests how well sand, charcoal, and jute sack are all effective in retaining water for evaporation. Photo: MIT D-Lab/Ava Dijstelbloem

Temperature and humidity sensors are placed inside each bucket so that we can compare the temperature and humidity inside to the ambient temperature and humidity. We are using a Particle Argon to collect data, which uses wifi, so we can view our data at any time! Our other experiments that are currently running are testing different evaporative cooling configurations and structures made from local materials that we purchased in Lodwar. This upcoming weekend we will be testing prototypes at an archaeological field camp!

Group of people making charcoal briquettes in Keny.
We are turning a local invasive species, prosopis, into charcoal that will be used to retain water in some of the evaporative cooling designs. Left: Carbonizing the organic matter. Right: Making charcoal briquettes out of ground charcoal, yucca powder, and water. Photos: MIT D-Lab/Ava Dijstelbloem

The past two weeks have already been the most amazing experience, and we can’t wait to see what else we can learn about Turkana and evaporative cooling this summer!


About the authors

Christine Tang is a sophomore at MIT studying mechanical engineering. At D-Lab, she has taken Introduction to Energy in Global Development and is creating a system to survey people in low-income nations more efficiently. 

Ava Dijstelbloem is a sophomore at MIT studying mechanical engineering. She has taken D-Lab: Water Sanitation and Hygiene. She is also part of the evaporative cooling team at D-Lab, specifically looking at how to optimize the efficiency of clay pot coolers for fruit and vegetable preservation.


More information

Evaporative Cooling for Vegetable Preservation Research

Contact

Eric Verploegen, MIT D-Lab Research Engineer; Evaporative Cooling Research Lead