theertham presentation

7/28/2019 Theertham Presentation

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Theerthamnon governmental organization (NGO)

ornonprofit corporation

formed in the state of Texas, USA

to design, manufacture, distribute and tech transfer

very very low costsolar powered portable water distiller

Dr. Vishwa Narayan, BE(Hons)EEE, MSEE, PH.D. EE


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Quencher: solar powered water distiller

Produces 15 to 20 litres of water per day

from a simple, robust, long lastingdevice

costing INR 5000 (USD 100) or less per device

making potable water under 2 paise per litre (with 50years of usage)

without chemicals or consumables such as replaceablefilters

targeting at least 100 million units in service across allcontinents within 10 years


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Do we need a solar powered water distiller?

You bet!

show me a developing economy and I'll show you people who

are dying for lack of clean, potable watershow me a developed economy, and I'll show you people whoare supplied water in an extravagantly expensive manner

such as after a natural disaster(e.g., after Hurricane Katrina,water was air dropped from helicopters for weeks)


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How could water get contaminated?

In many many ways....

Gross contaminants such as particulates

Bacteria, viruses, bugs of all sorts; pathogens in general

Heavy metals: lead, arsenic, etc.,

Otherchemical pollutants (pesticides, plastics, etc.,) In general, Hydrocarbons of all sorts

Colloidal substances

Dissolved chemicals

Pharmaceutical run-off

salt


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any solar water purifier worth its salt must:

consistently sate thirst

be very very affordable lets say costs no more than 100 USD or 5000 INR

must purify salt waterand all kinds ofdirty water

must produce 15-20 litres (~3-4 gallons) of drinking waterper sunny day

must be totally solar powered, not requiring wall or battery power sources

must be portable, weighing no more than 50 pounds

must workin all climates and latitudes, year round

must be rugged and work for a minimum of50 trouble free years

must be very simple to set up and use by people of all ages, from all cultures

now *that* is a useful solar water purifier


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the sun sends tremendous amounts ofenergy towards the earth...

Over a full sunny day, 10.6 kilowatt-hours of energy falls on everysquare meter of surface area at Daggett CA.

on average 2725 kilowatt-hours of energy falls on 1 square metereach year. Averaging about 7.5 kilowatt-hours per day, making

Daggett one of the most sunny places on earthOslo, Norway receives 2.3 kilo-watt-hours-per-square-meter-per-day. Miami, Florida? 5.3. India? varies from 4 to 7 with about15002000 sunshine hours per year, depending upon location

many parts of the world receive an average of 5 kilo-watt-hours-

per-square-meter-per day of energy from sunshine

that is like running a microwave oven non-stop for 5 hours


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how much energy is required to convert 1litre of water into steam?

4.2 KJ of energy to raise the temperature of 1 litre of waterby 1 C

315 KJ of energy to raise the temperature1 litre from 25 to 100 C

420 KJ of energy to raise the temperature of1 litre from 0 to 100 C

2260 more KJ to convert all of1 litre of boiling water into steam

Converting 1 litre of boiling water into steam takes more than

5 times the energy required to convert ice into boiling water

ideal world: on average, 1 square meter collects 5 KWh (or 18 MJ) per day

ideal world: 7 litres of 25 C water -> steam (without latent heat reuse)

non ideal world, but with reuse of heat: more than 20 litres converted to steam

the trick is to reuse the latent heat of condensation of water-steam, as the steamcondenses


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One schematic of the quencher


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Quencher's components

Absorbs-sunlight-and-heats-water: absorber

Evaporates-water-to-steam: evaporator

Condenses-steam-to-pure-water: condenser

Key components: absorber-evaporator-condenserisbest designed as a unit, compact, heat-efficient

Waste and sludge remover removes residue or sludgewaste remover:hardy, removable,cleanable

Sun tracker and stand Input and output tanks, filters, spigots


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Absorber selective absorber

High emissivity at sunlight wavelengths

Low emissivity at 90-100 Cwavelengths


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Evaporator and Condenser

Evaporator and condenser are coupledthermodynamically

Latent heat of condensation is reused to

preheat raw water, improving system efficiency


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Absorber-evaporator-condenser-heatsource


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Heat pipe based radiative solar heater

Custom heat pipe


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sun tracker (if required)


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Did you say paisas per litre??

yes I did:) here's how

assume device costs conservativeINR 5000 (USD 100)

and this is a very reasonable target, in high volumes

assume an average 5 kWh of energy collected (1 sqm collector)

assume a conservative 15 litres of distilled water per day

cost of water per litre per year = 5000/(365*15) = 92 paisa

cost of water over 10 years = 92/10 = 9.2 paisa

cost of water over 25 years = 92/25 = 3.6 paise cost of water over 50 years = 13.7/50 = 1.8 paisa


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Water is one of four key elementsLet us make sure we have enough of it to drink

...for all of us...

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