Case Study – Membrane Distillation used in UNICEF Sweat Machine

Guide – Pradip Kumar MishraPresented by – Utkarsh Sethia

27th January , 2017

UNICEF Sweat Machine

UNICEF Sweat Machine

• The device spins and heats the material to remove the sweat, and then passes the vapor through a special membrane designed to only let water molecules get through

• Built by - Andreas Hammar (Swedish engineer)• Technology developed by - Sweden's Royal Institute

of Technology and the water purification company HVR

UNICEF Sweat Machine

Mechanism of UNICEF Sweat Machine

• Sweat Machine works by using membrane distillation (MD) to separate water from other components of sweat.

• MD is a thermally-driven process that employs a hydrophobic, microporous membrane

• The water (or sweat) to be processed is heated, while the water on the permeate side of the membrane is kept cool.

Mechanism of UNICEF Sweat Machine

• The temperature difference across the membrane creates a corresponding difference in pressure which pulls water, in the form of vapor, over to the permeate side of the membrane.

• Water’s naturally high surface tension keeps the liquid phase of the water out of the membrane’s pores.

UNICEF Sweat Machine

Why Membrane Distillation• It is a good choice for compact desalination and

water purification units• The process doesn’t require the energy and

equipment to create the extreme pressures needed for reverse osmosis.

• Heating the feed water can be done with the waste heat of a power plant or factory or with renewable energy sources like solar power.

UNICEF Sweat Machine

• The amount of water it produces depends on how sweaty the person is - but one person's T-shirt typically produces 10ml

• Water extracted from the machine is actually cleaner than the ordinary swedish tap water

What Andreas Hammar has to say

• "We use a substance that's a bit like Gore-Tex that only lets steam through but keeps bacteria, salts, clothing fibres and other substances out.”

• "They have something similar on the International Space Station to treat astronaut's urine - but our machine was cheaper to build.”

What is Gore-Tex

References• Article (http://www.mynewsdesk.com/)- The worlds first sweat

machine produces clean water for children • Article (http://www.npr.org/) - Thirsty? 'sweat machine' turns

perspiration into drinking water• Article (http://www.bbc.com/) - Machine turns sweat into drinking

water for Unicef• Article (http://www.sterlitech.com/) - Unicef uses membrane

distillation to make sweat drinkable• Article (http://www.independent.co.uk/) - Unicef's 'sweat

machine' turns perspiration into drinkable water

Thank you