Page 1

DEW HARVESTING

An Alternative Water Source for Tanzania by Emre รœngรถr


INTRODUCTION: Our master programme pursues to explore the intersection between architecture, technology, researchers and the environment. Through a site-specific approach, we aim to respond to present and future global challenges through research by design and direct on-site involvement in the form of active expeditions to remote world locations. In November 2017, “Architecture and Extreme Environments” students set off to Tanzania and tested their site specific “devices” over there for a month. This booklet is the documentation of the data collection, design and testing process of my device.

CONTEXT: Due to the lack of clean water resources 23 million people in Tanzania, almost half of the country’s population, do not have access to safe water. Typically, women and children spend over two hours a day collecting water, and up to seven hours in remote areas. Access to toilets is even lower – at around 15% of the population. These issues have a big impact on health, with over 3,000 children under five dying each year from preventable diarrhoeal diseases caused by poor water and sanitation. People collect the rain in the rainy seasons but the dry seasons bring the drought with itself.

CONCEPT: The project aims to generate water with the yearlong stable humidity for the settlements that do not have access to water infrastructure. The intention is to collect dew during the night and before sunrise. Dew is the tiny drops of water that form on cool surfaces at night, when atmospheric vapour condenses. The intention is cooling the surfaces by radiative cooling on different surfaces with various patterns and test the efficiency. The experiments were done and measured through five different surfaces in total, three surfaces with the size of 1 m2 and two surface with the area of 0.35 m2. The surfaces were tested on the roofs with different heights. The experiments were carried out in Copenhagen, Denmark and several places in Tanzania; Magoda, Amani, Dar es Salaam and Muheza.

CONTENT: 1. DATA COLLECTION 2. DEVICE CONCEPT 3. DETAILS, DRAWINGS & PRODUCTION 4. EXPEDITION & PERFORMANCE

KA C DK T -S

- EMILIE J CEC IAGO D ILIE J - T CHRISTOPHE E I B S I J U M E O L M RE - NIC V Ü IE MI Y ARCHI -C U TE OF

E AOL OF ITION CTURE NV -D URCHO EXPED 2017

TANZANIA

M L - GEORGE P - ADA IS A - LIN Z - MAHAMED JARL AK NN KE B - S DE DER N K- E R

N B TS SA K MEN LE ON RK IRENMA

VID G - JAKOB S - DA K MIA K C - LILLI W - CH - THO C RIST H A J IAN MAS AS C LHL ILLE T R EX E A ND ARCHITE ME E AM

Tutors: David Garcia Jakob Knudsen Thomas Chevalier Bojstrup Marianne Hansen

L F - VIKTORIA K - XAN HAE B TA MIC A N - EDI D - ALICJA - VA C - - ANN S - T LER AN KE W OM IK


DATA COLLECTION

/Infographics /Water Facts /Accesibility /Climate Data /Condensation /Radiative Cooling /Dew Harvesting /Reference Projects


TA N Z ANI A

HEALTH: WATER

NO ACCESS TO CLEAN WATER

NO ACCESS TO SANITATION

UNDER FIVE YEAR OLD DEATHS

26 MILLION PEOPLE

44 MILLION PEOPLE

3,300 CHILDREN

26 million people in Tanzania do not have access to clean water

44 million people in Tanzania do not have access to adequate sanitation

Over 3,300 children under five die a year due to diarrhoael diseases caused by poor water

RESOURCES, ACCESIBILITY & WATERBORNE DISEASES

Tanzania population: 55 million

no water

no sanitation

water

sanitation

844 MILLION PEOPLE

2.3 BILLION PEOPLE

289,000 CHILDREN

844 million people in the world - one in ten - do not have access to clean water

2.3 billion people in the world - one in three - do not have access to adequate sanitation

289,000 children under five in the world die each year due to diarrhoeal diseases caused by poor water and sanitaiton. That’s 800 a day or 1 child every 2 minutes

World population: 7.5 billion

Lake Rushwath

Urban Wate

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Lake Manyara

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ACCESIBILI TY

56

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very low

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DATA COLLECTION

Source:

ell/B

low

2-20

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very high

7% 22 1 728,

Tub

6.5% 709,044

medium

20-100

bli

AL OT NT I YED RVE OF D S SU RINK D L O ING WA H TER // 9,276,997 HOUSE

Protected (covered) Dug Well

100-300

GROUNDWATER VULNERABILITY

807

3,

% ,4 18 612 1,

MA IN SO UR CE

29,

FE M AL E

HY NIA DR ZA OGE TAN OLOG F O Y & WATER POINT MAP

HO US EH OL DS

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2% otect ed 20 Sp 3, rin 13 g 3

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EA D ED

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MAJOR GROUNDWATER BASINS

Mbar angan

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Ruvu

LEGEND Groundwater resources and recharge (mm/a)

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access at lack ater ians th w Tanzan ved drinking ro to imp sources

no with ians proved zan Tan ss to im acce ation t sani

Average pupils/ latr drop ho ines le in public

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World population: 7.5 billion

ici

Sc fun hool wa ctio s wit shi na h n ng l ha o fac nd ilit ies

46%

t rac sp ian on an cti nz efe Ta en d op

P w opu fo ith lati od so on ap w be ho fo w re as pr h ep ha ar nd in s g

and sanitation in Tanzania

Tanzania population: 55 million

Annual number of under five deaths in Tanzania (2012): 98,000

Tanzania is the largest country in East Africa, home to over 52 million people. Due to the hot climate, safe water is scarce and growing enough food is often difficult for the mostly rural population. 23 million people in Tanzania do not have access to safe water. Typically, women and children spend over two hours a day collecting water, and up to seven hours in remote areas. Access to improved sanitation is even lower, it’s just 13% of the population. This is particularly problematic to health in densely populated, unplanned settlements. These issues have a big impact on health, with over 3,000 children under five dying each year from preventable diarrhoeal diseases caused by poor water and sanitation. There are wider impacts too on education, livelihoods and wellbeing.

300km

| INFOGRAPHICS

LOCAL AQUIFERS

WATER ACCESS POINTS

>100

functional

<100

functional needs repair

non functional

-www.cdc.gov -www.who.int -www.wateraid.org -microdata.worldbank.org -data.worldbank.org -thewaterproject.org -www.unicef.org -www.nbs.go.tz

Map Source:

-geoviewer.bgr.de -opendata.go.tz -earthwise.bgs.ac.uk


TA N Z A N I A

HEALTH: WATER TREATMENT CONTAMINANTS & METHODS Tanzania suffers from serious issues involving its people in regards to water. In a nation where one third of the country is arid to semi-arid, it is very difficult for people to find access to clean, sanitary water if they don't live near one of the three major lakes that border the country. As a result, Tanzania's ground water is the major source of water for the nation's people; however it's not always clean. Many of these ground water wells are located near or next to toxic drainage systems, which leak into the fresh ground water and contaminate it. Consequently, Tanzanians turn to surface water which contains things like bacteria or human waste; and people have no choice but to drink from, bathe in or wash their clothes in these areas.

PARTICULATES

BACTERIA

MINERALS

CHEMICALS

PHARMACEUTICALS

Methods to remove these elements range from simple and inexpensive to elaborate and costly. This board consists of 24 methods and divided into four categories: separation, filtration, chemicals, oxydation. The methods listed in an order of low to high technology and efficiency.

LOW EFFICIENCY

LOW TECH

-

HIGH TECH

47

Ag

+ + +

107.868

NT

NT

NT

NT

NT

T

-SEPARATION METHOD-

-FILTRATION METHODS-

-FILTRATION METHODS-

-FILTRATION METHODS-

-FILTRATION METHODS-

SEDIMENTATION

GRANULAR CHARCOAL

PLANTS

PAPER or CLOTH

POROUS STONE/CERAMIC

SILVER

Gravitationally settles heavy suspended material.

Cheap, but water can flow around the granules without being treated.

There are numerous plants, animals and organisms that are quite effective in filtering water.

Filters are disposable and filter to one micron, but do not have much capacity.

Filters are small but expensive, and do not effect chemicals, bacteria or odors.

An effective bactericide but a cumulative poison which concentrates and doesn't evaporate.

Air

-CHEMICALS METHODS-

N2, O2, Ar, CO2..

53

I

126.904

NT

NT

NT

NT

T

-FILTRATION METHODS-

-OXYDATION METHODS-

-FILTRATION METHODS-

-FILTRATION METHODS-

-FILTRATION METHODS-

SLOW SAND

AERATION

POWDERED CHARCOAL

PRESSURE SAND

DIATOMACEOUS EARTH

IODINE

1 cubic meter passes about 2 liters/min, and does a limited bacteria removal.

Sprays air into the water to raise the oxygen content, to break down odors, and to balance the dissolved gases. However, it takes space, is expensive, and picks up contaminants from the air.

Very fine dust useful for spot cleaning larger bodies of water, but is messy and can pass through some filters and be consumed.

1 cubic meter passes about 40gpm and must be backwashed daily.

Removes small suspended particles at high flow rates, must be daily backwashed and is expensive.

Not practical, and is mostly used by campers.

O

3

17

35

Cl

Br

Piped Water into

NT -SEPARATION METHODS-

NT -OXYDATION METHODS-

O O

T -CHEMICAL METHODS-

-CHEMICAL METHODS-

H

34.453

79.904

Dwe 11 % lling 1,072 ,656

NT

T -CHEMICAL METHODS-

H

NT -FILTRATION METHODS-

T -CHEMICAL METHODS-

DISTILLATION

OZONE

BROMINE

CHLORINE

REVERSE OSMOSIS

HYDROGEN PEROXIDE

Boils and recondenses the water, but many chemicals vaporize and recondense in concentration in the output water. It is also expensive to boil & cool water.

Very good bactericide, using highly charged oxygen molecules to kill microorganisms on contact, and to ozidize and flocculate iron, manganese and other dissolved minerals for post-filtration and backwashing.

Used in pools and spas, doesn't smell or taste as bad and doesn't kill bacteria very well.

Common, cheap, but extremely toxic. It does not decrease physical or chemical contamination, it does increase colesterol formations, is a carcinogen, and causes heart disease.

Uses a membrane with microscopic holes that require 4 to 8 times the volume of water processed to wash it in order to remove minerals and salt, but not necessarily chemicals and bacteria.

Kills bacteria with oxygen, is chemically made and is very toxic. It is used in emergencies.

ate r ot

O -

HIGH EFFICIENCY

NT

R

+ +

C

O

H

UV

+ +

NT

NT

NT

NT

NT

-SEPARATION METHODS-

-OXYDATION METHODS-

-FILTRATION METHODS-

-CHEMICAL METHODS-

-CHEMICAL METHODS-

BOILING WATER

ELECTRONIC PURIFICATION and DISSOLVED OXYGEN GENERATION

COMPRESSED CHARCOAL/ CARBON BLOCK

NONTOXIC ORGANIC ACIDS

ION EXCHANGE

ULTRAVIOLET LIGHT

Should be used with caution in large water plants only.

Exchanges sodium from salt for calcium or magnesium, using either glauconite (greensand), precipitated synthetic organic resins, or gel zeolite, thus softening the water. Minerals, metals, chemicals or odors are not affected, and the water is salty to drink.

Good bactericide, but has no residual kill, and works only in clearly filtered water. Still in its infancy stage is a new technology involving super white light.

For 15 to 20 minutes kills 99.9% of all living things and vaporizes most chemicals. Minerals, metals, solids and the contamination from the cooking container become more concentrated.

Creates super oxygenated water in a dissolved state that lowers the surface tension of the water and effectively treats all three types of contamination: physical, chemical and biological.

The best type of charcoal filter, can remove chemicals and lead, but is easily clogged, so should be used with a sediment prefilter.

-SEPARATION METHODS-

Source:

-www.cdc.gov -www.enviroalternatives.com -www.merrywater.co.tz -www.unicef.org -thewaterproject.org

DATA COLLECTION

| INFOGRAPHICS


26 Million people donâ&#x20AC;&#x2122;t have access to clean water

Tanzania population: 55 million source: Water Aid UK

41 Million people donâ&#x20AC;&#x2122;t have access to decent sanitation

Tanzania population: 55 million source: Water Aid UK

3300 children under 5 die from diarrhoea every year Caused by dirty water and poor toilets source: Water Aid UK

DATA COLLECTION

| ACCESIBILITY


DATA COLLECTION

| ACCESIBILITY

DAWASCO tap - tanker

DAWASCO tap - pushcart

DAWASCO small vendor

DAWASCO large vendor

Jerry can - pushcart - borehole

Tankers - direct

Trucks - direct

Pushcart vendors - salty water

DAWASCO jerry can

DAWASCO trucks

Private borehole / small

Private borehole / large

Piped household connection - Private provider

Community borehole

DAWASCO tap

Piped household connection - Community provider

Piped household connection - DAWASCO

US $ per m3

16 Water Tariffs Dar es Salaam

14

12

10

8

6

4

2

Denmark water tariff: 3.34$ per 15 m3

WATER SUPPLY

Private water vendors provide a means by which households without an individual piped connection to the utility network access water across Dar es Salaam. Water kiosks in Dar es Salaam provide safe drinking water for poor households in peri urban areas of the city.

source: tariffs.ib-net.org


100

HUMIDITY %

80 60 40 20

JAN

FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

OCT

NOV

DEC

HUMIDITY Tanzania doesn’t have enough clean water resources and almost half of the population don’t have access to drinking water sources. However, people can collect rain water during the rain season if they invest in gutters or alternative collection systems. Beside the rain season, humidity is considerably high all year long (80%). Device focuses on this aspect.

DEW POINT Even the humidity is high all year long, condensation of the humid air is needed for water collection. Dew point is the condensation temperature of humid air in relation to relative humidity. Due to tropical climate, temperature is almost stable all year also the change between day and night is not huge, so the air temperature usually can’t reach the dew point. Therefore cooling the condenser is key for the dew collection. source: weather.com

DATA COLLECTION

| CLIMATE DATA


RADIATIVE COOLING The cooling of the Earth’s surface and the air near the surface, occurring chiefly at night. It is caused by the emission of infrared radiation from the Earth’s surface and from the tops of clouds and the atmosphere. Because infrared radiation is absorbed by water vapor, cloudless nights usually allow for greater radiational cooling than overcast nights. Radiational cooling occurs in all regions of the Earth and is important in maintaining the Earth’s energy balance.

Aluminum Anodized Water Stainless Steel PVC Polypropylene Polytetrafluoroethylene (PTFE) Plaster Silicon

0.77 0.95 - 0.963 0.85 0.91 - 0.93 0.97 0.92 0.98 0.83 - 0.96

EMISSIVITY The radiation heat transfer emissivity coefficient of some common materials. The emissivity coefficient indicates the radiation of heat from a ‘grey body’ according the Stefan-Boltzmann Law, compared with the radiation of heat from a ideal ‘black body’ with the emissivity coefficient = 1. The emissivity coefficient for some common materials can be found in the table below. Note that the emissivity coefficients for some products varies with the temperature. As a guideline the emmisivities below are based on temperature 300 K.

DATA COLLECTION

| CONDENSATION


DEW HARVESTING Dew harvesting (or dew collection) is simply taking advantage of water vapor in the atmosphere to harvest clean and potable water through condensation, a passive process that allows water particles to return to the earth in a pure form. Dew harvesting has been practiced by humanity as far back as ancient times, in areas where rainfall and groundwater resources are scarce. When there is any humidity at all in the air and there is a surface that is cool enough to provoke condensation, dew will condense on that surface until the humidity is gone. Vegetation in desert regions have developed modifications that allow them to collect their own humidity from the air, for example, and through efforts of reforestation in desert regions this technology has advanced abundantly around the world.

DATA COLLECTION

| DEW HARVESTING


DATA COLLECTION

| DEW HARVESTING REFERENCES


DEVICE CONCEPT

/Early Ideas /Usage /Intention /Prototypes /References


ATMOSPHERIC WATER GENERATOR Night time has the lowest temperatures of the day. The device will work in the highest performance between the hours 2a.m. - 6a.m. The aim is to take advantage of the device all day long. In order to achieve this the condenser part has to reach the dew point which is 22C. In the day time there is a need of electricity to cool the condenser such as peltier elements in addition to passive systems such as radiation reflecting materials and photon shields. In the night time the passive systems will be enough for condensation. The idea is having fans/propellers on the top of the device in order to supply a better air intake. The air will move into a copper coil through a tapering connection piece that creates a Venturi effect and cools down the air with pressure. The copper coil will be the condenser part. The coil will be filled with copper wool that increases the surface area for condensation. Imagine this as the fog catcher nets inside a copper coil. For the day time there will be a peltier element that is powered by a solar panel. Condensation part will be covered with a layer of humid ground that evaporates through the day and cools down the condenser. The canopy of the device will be designed with reflective material to reduce the heat inside.

DEVICE CONCEPT

| EARLY DEVICE STRATEGIES


ROOF ELEMENT The device will be deployed on the slumsâ&#x20AC;&#x2122;s roofs. Most of the slums have single steel sheet roofs that are rusty and dark colored and lacking insulation. Device aims to reflect to sunlight and cool down the roof and contribute to the cooling of the house while it catches the dew and generates water during the nights. The intention is producing cheap and easy to build systems that the locals can afford and even can build from scrap. They can use it without changing their whole roof or structure, therefore it wonâ&#x20AC;&#x2122;t take long time to assemble and will be cost effective.

DEVICE CONCEPT

| USAGE


PROTOTYPE #1 The prototypes were produced and tested in Copenhagen. Two different surfaces were tested; silicon filled bumps and plain surface. Both are 0.35 m2 and same materials were used for both surfaces. The surfaces were deployed on a roof facing NW direction in order to extend the shading time in the morning to prevent evaporation.

DEVICE CONCEPT

| PROTOTYPE #1


SLIPPERY ASSYMETRIC BUMPS “We experimentally found that the geometry of bumps alone could facilitate condensation,” said Kyoo-Chul Park, a postdoctoral researcher and the first author of the paper. “By optimizing that bump shape through detailed theoretical modeling and combining it with the asymmetry of cactus spines and the nearly friction-free coatings of pitcher plants, we were able to design a material that can collect and transport a greater volume of water in a short time compared to other surfaces.” Time lapse of droplets growing faster on the apex of the bumps compared to a flat region with the same height. (Courtesy of the Aizenberg Lab/Harvard SEAS) An array of slippery asymmetric bumps shows a significantly greater volume of water collected at the bottom of the surface compared to the flat slippery surfaces. (Courtesy of the Aizenberg Lab/Harvard SEAS)

DEVICE CONCEPT

| REFERENCE


Existing Roof Insulation Material

Radiating/Condensing Surface

BUMPY SURFACE PROTOTYPE Bumpy surface design was developed in the light of SLIPS study. The prototype tested two main aspects. First one is if the bumps can attract the water in the air better compared to a flat surface. Second aspect is if they help the water drops to roll down in the storage area before evaporating. First tests were done with a regular bubble wrap. It was attached to a 5cm polystrene insulation board and the corners were covered with reflective tape in order to minimize the heat transfer between the frame and the condenser. The tests have shown that, bumps on the bubble wrap were too dense and the surface wasn’t slippery enough as a result of the properties of the material so it didn’t work efficiently. One other thing, it wasn’t possible to attach the membrane tightly so the drops were stuck.

DEVICE CONCEPT

| PROTOTYPE #2


SILICON FILLED BUMPS PROTOTYPE The intention is using the silicon as a thermal bridge as well as using its white bright colour as a heat reflective element. The size of each bump is; 12mm in length, 4mm in width at the top and 8mm in width at the bottom. The height of each bump is 2mm. The horizontal distance between each bump is 23mm from their centre and the vertical distance is 10mm from the end point to the start point. The size was developed in collaboration with Professor Kenneth Park from Harvard University who worked on SLIPS experiments. The pattern was cut in the laser cutter and used as a frame for welding. The bumps were welded half way then filled with silicon and then fully welded with a soldering iron. It was tested in Copenhagen on top of a roof and left overnight.

DEVICE CONCEPT

| PROTOTYPE #3


DETAILS DRAWINGS & PRODUCTION

/Condensing Surfaces /Pattern Design /Condenser Layers /Free Standing Structure /Roof Element /Production Phase /Elements


Braided rope Rope thimble Plexi connection element

Transparent plastic

Hydrophobic burls

120 cm

bumps

Water collection pocket

Water distribution pipe

80 cm

SILICON FILLED BUMPS The â&#x20AC;&#x153;silicon filled bumpsâ&#x20AC;? surface is consisted of an aluminium based membrane frame and PVC based transparent main surface. The intention is using the silicon as a thermal bridge as well as using its white bright colour as a heat reflective element. The size of each bump is; 12mm in length, 4mm in width at the top and 8mm in width at the bottom. The height of each bump is 2mm. The horizontal distance between each bump is 23mm from their centre and the vertical distance is 10mm from the end point to the start point. The pattern is produced with a laser cutter, and then is used as a template for welding. PVC based membranes welded half way with a soldering iron and then the areas filled with white sealing silicon one by one and welded.

DETAILS, DRAWINGS & PRODUCTION

| CONDENSING SURFACE


Braided rope Rope thimble Plexi connection element

120 cm

Spheres

Water collection pocket

Water distribution pipe

80 cm

SPHERES The “spheres” surface is consisted of an aluminium based membrane frame and main surface. According to the study “Pulling Water from Thin Air” by Harvard University Wyss Institute; “…dew droplets grow faster on the apex of the bumps compared to a flat region with the same height.” The surface was designed influencing from this study. The diameter of each sphere is 3mm and the height is 1mm. The surface was produced with a laser cutter. The horizontal distance between each bump is 7mm from their centre and the vertical distance is 5mm from the end point to start point.

DETAILS, DRAWINGS & PRODUCTION

| CONDENSING SURFACE


Braided rope Rope thimble Plexi connection element

Reflective plastic

Reflective plastic

120 cm

Spheres

Water collection pocket

Water distribution pipe

80 cm

MICROGROOVES The â&#x20AC;&#x153;microgroovesâ&#x20AC;? surface is consisted of an aluminium based membrane frame and main surface. It is influenced from the rice leaf and designed according to that. The pattern is consisted of 330 straight lines with the thickness of 0.2mm. 330 lines are divided into 55 groups that has 6 lines each. The distance between each group is 0.4mm. The pattern is produced with a laser cutter. The reflective side of the aluminium membrane was cut and due to the size of the laser cutter it was produced in 2 pieces and then welded together with a soldering iron.

DETAILS, DRAWINGS & PRODUCTION

| CONDENSING SURFACE


Braided rope Rope thimble Plexi connection element

120 cm

Bumps

Water collection pocket

Water distribution pipe

80 cm

BUMPS The â&#x20AC;&#x153;bumpsâ&#x20AC;? surface is consisted of an aluminium based membrane frame and PVC based transparent membrane main surface. The size of each bump is; 10mm in length, 4mm in width at the bottom and 2.5mm width at the top. The height of each bump is 2mm. The bumps are located asymmetrically in order to direct the drops more efficiently. The horizontal distance between each bump is 15mm from their centre and the vertical distance is 10mm from the end point to start point. The pattern has first laser cut on a 10mm MDF and then the PVC based transparent membrane was vacuum formed on the laser cut pattern. Due to the size of the vacuum former, the surface was produced in 6 pieces and then welded together with a soldering iron.

DETAILS, DRAWINGS & PRODUCTION

| CONDENSING SURFACE


4mm

2mm

MICROGROOVE PATTERN

330 lines 55 groups x 6 lines

15mm

2.5mm 10mm 4mm

10mm

BUMPS PATTERN

2544 bumps 6 groups

7mm 5mm

16254 spheres

SPHERE PATTERN

DETAILS, DRAWINGS & PRODUCTION

| PATTERN DESIGN


Transparent PVC Aluminium membrane

Transparent PVC

Double layer PVC

Insulating fabric

LAYERING The â&#x20AC;&#x153;silicon filled bumpsâ&#x20AC;? surface is consisted of an aluminium based membrane frame and PVC based transparent main surface. The intention is using the silicon as a thermal bridge as well as using its white bright colour as a heat reflective element. The size of each bump is; 12mm in length, 4mm in width at the top and 8mm in width at the bottom. The height of each bump is 2mm. The horizontal distance between each bump is 23mm from their centre and the vertical distance is 10mm from the end point to the start point. The pattern is produced with a laser cutter, and then is used as a template for welding. PVC based membranes welded half way with a soldering iron and then the areas filled with white sealing silicon one by one and welded.

DETAILS, DRAWINGS & PRODUCTION

| CONDENSER LAYERS


45° Condenser

40° 35° 30° Steel connection 25° Main pole #2 20° Horizontal structure 15° 10°

Steel mid connection

M5 bolts

Double pulley

Top connection Main pole #1

Steel anchor

Rope distribution disk

FREE STANDING STRUCTURE FREE STANDING STRUCTURE Free standing structure is consisted of a main vertical pole and horizontal sec-

Free standing structure is consisted a on main vertical and secondary poles. The main pole of stands an anchor and it ispole consisted fromhorizontal two aluminium and stands connected on through mid steel piece. through the from two ondary poles. The mainpoles pole anaanchor andA itdiskisgoes consisted pole and lifts the whole structure that is connected with ropes. On top there is a aluminium poles and connected through midHorizontal steel piece. disk goes through the carabiner that adjusts the way of thearope. structure A is the mid connection between the surfaces and main pole. It aligns the surfaces and consists of 3 pole and lifts the whole structure that is connected with ropes. On top there is a aluminium poles and connected with steel pieces. carabiner that adjusts the way of the rope. Horizontal structure is the mid connecSurface angle is an important parameter for the tests. The red lines on the main tion between the surfaces and main Itarealigns surfaces andFor consists of 3 pole are for the specific anglespole. and they painted the for every 5 degree angle. precision surfaces are first placed at a particular with distancesteel from the pole and then aluminium poles and connected pieces. connected to the mid structure so one can just change the height of the disk and adjust the angle.

Surface angle is an important parameter for the tests. The red lines on the main pole are for the specific angles and they are painted for every 5 degree angle. For precision surfaces are first placed at a particular distance from the pole and then connected to the mid structure so one can just change the height of the disk and DETAILS, DRAWINGS & CONSTRUCTION | FREE STANDING STRUCTURE adjust the angle.

DETAILS, DRAWINGS & PRODUCTION

| FREE STANDING STRUCTURE


ROOF ELEMENT Roof set-up is mobile and specifically designed for the informal settlements that donâ&#x20AC;&#x2122;t have decent water or electricity infrastructure. The intention is deploying the surfaces on the roofs of the informal settlements/slums without needing a complicated infrastructure. They are tensed with ropes from four corners and anchored to the ground with spikes. The collection area has a slope of 4 degrees and it directs the water to the main collection pipe (6mm). The pipe is extended with a separate pipe (10mm) and it can be directly connected to the water storage units. Another aspect is the heat transfer between the roof and condensers. A thin layer of textile were used as an insulation layer. The amount of surfaces can be increased if needed and can replaced without any complicated or expensive equipment.

DETAILS, DRAWINGS & PRODUCTION

| ROOF ELEMENT


PRODUCTION PHASE All the surfaces have a reflective frame which is consisted of an aluminium film that is covered by transparent plastic membrane on both sides. The main surfaces differ according to the pattern. Two different materials were used for the main surfaces; aluminium based reflective film and PVC based transparent film. An adjustable soldering iron were used at 150째C for PVC-PVC connections, 200째C for PVC-Aluminium connections, 260째C for Aluminium- Aluminium connections and 330째C for Aluminium-PVC-Aluminium connections. Water channel connections were welded with an ultrasonic welder.

DETAILS, DRAWINGS & PRODUCTION

| PRODUCTION


3 1

2

6 4

7

8

5

9

10 11

12

13

15

14

16

ELEMENTS ELEMENTS 1. Thimble // 8mm steel X 20 7. Steel disk // 2mm 12. Braided rope // Ø 10mm 15m 2. PVC pipe // Ø 10mm X1.20 8. Aluminium pole (horizontal structure) //12.ØBraided rope 13. Top connection // Ø 20mm steel tube Thimble // 8mm steel X 20 7. Steel disk // 2mm // Ø 10mm 15m 2. PVC pipe // Ø 10mm X 20 pole (horizontal structure) // Ø 13. Top connection Ø 20mm steel tubemid connection // Ø 16mm 3. Anchor // Steel 16mm X8. Aluminium 3 14.//Vertical pole // Steel 16mm X 3 14. Vertical pole mid connection // Ø 16mm 4. Spike // 2mm steel X 123.4. Anchor 9. Condenser // Various materials X 5 steel tube Spike // 2mm steel X 12 9. Condenser // Various materials X 5 steel tube 5. Horizontal // structure connection // Ø 20mm 10. Braided Ø 5mm 6m 6m X6 X 6 15. PVC pipe // 15. Ø 10mm X 20pipe // Ø 10mm X 20 5. Horizontal structure connection Ø 20mm 10. Braided roperope ////Ø 5mm PVC steel tube 11. Aluminium pole (vertical structure) // Ø 16. Lightholder // Ø 3mm rod X 6 steel tube 11. Aluminium pole (vertical structure) // Ø 16. Lightholder // Ø 3mm rod X 6 6. Plexi connection // 2mm X 40 20mm X 2 6. Plexi connection // 2mm X 40 20mm X 2

DETAILS, DRAWINGS & CONSTRUCTION

| DEVICE COMPONENTS

DETAILS, DRAWINGS & PRODUCTION

| DEVICE COMPONENTS


EXPEDITION & PERFORMANCE

/Test Locations /Deployment /Test Set Up /Tests /Results /Conclusion


Amani Nature Reserve

Muheza

ZANZIBAR

Ardhi University Kinondoni

DAR ES SALAAM

TANZANIA TANZANIA

The surfaces were tested in three different locations; Amani Nature Reserve, Muheza, surfacesand were Ardhi tested in three different locations; Amani Nature ReKinondoni Dar esThe Salaam University Campus Dar es Salaam. The surfaces serve, Muheza, Kinondoni Dar es Salaam and Ardhi University Campus were deployed on metal roof in all tests, all the roofs were facing NW direction for Dar es Salaam. The surfaces were deployed on metal roof in all tests, all the roofs were facing NW direction for maximum shading in the morning. A maximum shading in the morning. A layer of “insulation” were used in between the layer of “insulation” were used in between the roof and surfaces in order to roof and surfaces inminimize orderthetoheat minimize transfer. the heat transfer. Amani Nature Reserve is a protected area located within the Muheza and Amani Nature Reserve is a protected area located within the Muheza and Korogwe Korogwe Districts in the Tanga Region of Tanzania. The nature reserve Districts in the Tanga Regioninof The nature was ofestablished in 1997 was established 1997Tanzania. in order to preserve the uniquereserve flora and fauna the East Usambara Mountains. The East and West Usambara Mountains in order to preserve the unique flora and fauna of the East Usambara Mountains. The are a biodiversity hotspot. The Amani Nature Reserve includes tropical East and West Usambara Mountains are a biodiversity hotspot. The Amani Nature Recloud forest habitats. The area selected as a testing location due to its high altitude and humidity. serve includes tropical cloud forest habitats. The area selected as a testing location due its inhigh altitude humidity. Kinondoni is to located the centre of Darand es Salaam. The intention is test-

ing the surfaces in a city scape covered with buildings and slums. The device deployed on a roof of a slum and were tested overnight. Ardhi University Kinondoni is located in the centre ofNorthern Dar espart Salaam. intention Campus is located in the of Dar esThe Salaam, it has severalis testing surroundingwith buildings but mainlyand it is surrounded by trees. Compared to es in a city scape covered buildings slums. The device deployed on Kinondoni it is further away from the ocean.

the surfaca roof of a slum and were tested overnight. Ardhi University Campus is located in the Northern part of Dar es Salaam, it has several surrounding buildings but mainly it is surrounded by trees. Compared to Kinondoni it is further away from the ocean.

|

EXPEDITION & PERFORMANCE | TEST LOCATIONS EXPEDITION & PERFORMANCE TEST LOCATIONS


ASSEMBLE

ASSEMBLE

The surfaces were transported as a single roll and deployed on the test locations. Depending on the deployment type, roof or free standing, following The surfaces wereassembled. transported as a elements

single roll and deployed on the test For the free standing structure there are 2 aluminilocations. Depending deployum poles with 20 mm thicknesson andthe 120 cm length and 3 side aluminium poles with 16 mm thickness ment type, roof or free standing, and 100 cm length as well as the connection pieces and ropes. following elements assembled. For theRoof freedeployment standing structure there are 2 doesn’t need any extra structures except ropes. The surfaces are tied tightened aluminium poles with 20 and mm thickwith ropes then directly deployed on the roofs. ness and 120 cm length and 3 side Both deployment types with need spikes anchoring aluminium poles 16 for mm thickthe ropes. ness and 100 cm length as well as the connection pieces and ropes. Roof deployment doesn’t need any extra structures except ropes. The surfaces are tied and tightened with ropes then directly deployed on the roofs. Both deployment types need spikes for anchoring the ropes. FREE STANDING STRUCTURE FREE STANDING

STRUCTURE

Free standing structure is consisted of a main vertical pole and horizontal secondary poles. The main pole stands on an anchor and it is consisted from Free standing isthrough consisted two aluminium polesstructure and connected a mid piece. vertical A disk goes pole throughand the pole and lifts of asteel main horizontal the whole structure that is connected with ropes. secondary poles. Thethat main pole stands On top there is a carabiner adjusts the way of the rope. Horizontal structure is the mid connecon tion an between anchor and it is consisted from the surfaces and main pole. It aligns the surfaces and consists of 3 aluminium poles and two aluminium poles and connectconnected with steel pieces.

ed through a mid steel piece. A disk Surfacethrough angle is an important parameter the the tests. goes the pole and for lifts The red lines on the main pole are for the specific whole that for is every connected with angles structure and they are painted 5 degree angle. For precision surfaces are first at a particular ropes. On top there is placed a carabiner that distance from the pole and then connected to the adjusts the way of the rope. Horizonmid structure so one can just change the height of the diskisand adjust the angle. tal structure the mid connection between the surfaces and main pole. It aligns the surfaces and consists of 3 aluminium poles and connected with steel pieces. Surface angle is an important parameter for the tests. The red lines on the main pole are for the specific angles and they are painted for every 5 degree angle. For precision surfaces are first placed at a particular distance from the pole and then connected to the mid structure so one can just change the height of the disk and adjust the angle. ROOF ELEMENT

Roof set-up is mobile and specifically designed for the informal settlements that don’t have decent water or electricity infrastructure. The intention is deploying the surfaces on the roofs of the informal Roof set-up is mobile andaspecifically settlements/slums without needing complicated infrastructure. They are tensed with ropes from four designed for the informal settlecorners and anchored to the ground with spikes. ments that don’t water The collection area hashave a slopedecent of 4 degrees and it or directs the water to the main collection pipe (6mm). electricity infrastructure. The intenThe pipe is extended with a separate pipe (10mm) and itiscan be directly connected to the wateron storage tion deploying the surfaces the units.

ROOF ELEMENT

roofs of the informal settlements/ Another aspect is theneeding heat transfera between the roof slums without complicated and condensers. A thin layer of textile were used as infrastructure. They areof tensed with an insulation layer. The amount surfaces can be increased can replaced any ropes fromif needed four and corners andwithout anchored complicated or expensive equipment. to the ground with spikes. The collection area has a slope of 4 degrees and it directs the water to the main collection pipe (6mm). The pipe is extended with a separate pipe (10mm) and it can be directly connected to the water storage units. Another aspect is the heat transfer between the roof and condensers. A thin layer of textile were used as an insulation layer. The amount of surfaces can be increased if needed and can replaced without any complicated or expensive equipment.

EXPEDITION & PERFORMANCE

| DEPLOYMENT

EXPEDITION & PERFORMANCE

| DEPLOYMENT


EXPEDITION & PERFORMANC


CE

| AMANI NATURE RESERVE


SURFACE #3 BUMPS

SURFACE #2

SURFACE #1

MICROGROOVES

SPHERES

AIR TEMPERATURE DATA LOGGER

SURFACE TEMPERATURE DATA LOGGER

RECEPTACLE

HOBO BASE STATION

30˚

ANGLE

POSITIONING

WIND

30° angle is the most efficient position for the condensing surface according to former studies. Surfaces can both collect the dew falling from the sky and help the dew particles to slip to the storage area.

In order to increase the condensation time and postpone the evaporation of the dew, orienting the condensing surface through north west direction is crucial since the shading is longer in the morning .

Wind decreases the humidity and speeds up evaporation process. For a better performance the condensing surfaces should be located on a less windy area, surrounded with trees etc. but there should never be a covering on top of the surfaces

EXPEDITION & PERFORMANCE

| TEST SET UP


EXPEDITION & PERFORMANCE

| DEPLOYMENT


PERFORMANCE

PERFORMANCE

| TEST LOCATIONS//AMANI NATURE RESERVE

| TEST LOCATIONS//KINONDONI DAR ES SALAAM

EXPEDITION & PERFORMANCE

| RESULTS


PERFORMANCE

| TEST LOCATIONS//ARDHI UNIVERSITY DAR ES SALAAM

EXPEDITION & PERFORMANCE

| RESULTS


EXPEDITION & PERFO


ORMANCE

| MUHEZA


EXPEDITION & PERFORMANCE

| DA


AR ES SALAAM MWENGE MARKET


Temperature/˚C 23

AMANI NATURE RESERVE Altitude: 930m Latitude/Longitude: 5˚05’S 38˚40’E Date: 26 - 27 November 2017 Time: 19:00 - 05:00

Hour

22,5

22

Ambient Temperature ˚C

Relative Humidity %

Surface Temperature ˚C 22,654

19:00

22,314

89.2

20:00

21,843

92.5

21,032

21:00

21,342

92.6

20,770

22:00

20,841

93.8

19,912 20,341

23:00

20,365

94.7

00:00

20,222

95.3

19,651

01:00

20,412

96.1

19,452

02:00

20,150

96.3

19,460

03:00

19,936

96.3

19,080

04:00

19.912

96.8

18,794

05:00

19,888

97.2

18,646

21,5

21

20,5

20

19,5

Ambient Temperature

19

Dew Point Surface Temperature Dew Zone

DAR ES SALAAM-KINONDONI

18,5 19:00

20:00

22:00

00:00

02:00

04:00

06:00

06:00

Time/hours

21:00

23:00

01:00

03:00

05:00

07:00

06:00

Time/hours

08:00

Time/hours

Temperature/˚C

Altitude: 1m Latitude/Longitude: 6˚47'0"S 39˚16'0"E Date: 5 - 6 December 2017 Time: 20:00 - 06:00

38

36

Hour

Ambient Temperature ˚C

Relative Humidity %

Surface Temperature ˚C

20:00

27,653

73,3

27,924 26,989

21:00

28,196

74,5

22:00

27,998

75,4

26,818

23:00

27,727

76,1

26,378

00:00

27,456

77,2

26,475

01:00

27,259

77,5

26,036

02:00

27,530

79,2

26,622

03:00

26,646

83,1

26,085

04:00

26,426

84,7

25,987

05:00

27,308

85,8

27,014

06:00

29,464

78,2

30,066

34

32

30

28

26

Ambient Temperature Dew Point

24

Surface Temperature Dew Zone

Temperature/˚C

DAR ES SALAAM-ARDHI UNI.

32

Altitude: 7m Latitude/Longitude: 6˚47'0"S 39˚16'0"E Date: 6 - 7 December 2017 Time: 20:00 - 06:00

31

Hour

Ambient Temperature ˚C

Relative Humidity %

Surface Temperature ˚C

20:00

28,473

82,6

28,226

21:00

27,996

83,5

27,883

22:00

27,798

84,2

27,528

23:00

27,785

84

26,976

00:00

27,443

84,4

26,975

01:00

27,559

85,3

27,336

02:00

27,835

86,5

26,420 26,313

03:00

26,683

87,6

04:00

26,412

88,5

26,115

05:00

25,902

86

25,854

06:00

25,967

78,1

25,891

30

29

28

27

26

Ambient Temperature Dew Point

25

Surface Temperature

20:00

22:00

00:00

02:00

Dew Zone

EXPEDITION & PERFORMANCE

| RESULTS

04:00

06:00


REFLECTIONS The project investigates an alternative water source and tests dew harvesting as a system. In the light of the outputs of the tests, we can fairly say that it is not possible to use this system as a primary water source for the households unless it is used in very large scales. On the other hand it doesn’t need any energy and much maintenance, so it will collect the water slowly and contribute the total water in the storage units. The device could be useful for remote areas or slums that don’t have access to water. During the rainy season people can easily collect water and sustain their lives but the dry season (8 months a year) brings water scarcity with itself. The surfaces can be both used as dew and rain collectors. The usage as a roof element would both contribute to water collection and radiative cooling so the roofs will be colder and the interior spaces as well. However, the manipulations on the surfaces have an effect on the total amount of collected water. If the surface can reach the dew point, the bumps will make the drops roll down easier. Especially silicon filled bumps are more effective in both cooling down the surface and collecting the droplets. Microgrooves are good at directing the drops to the storage area but they increase the friction between drops and the surface. The spheres also have the same problem, the density of the pattern is very high so sometimes the drops get stuck between the spheres. There are several ongoing discussions and proposals on the possible usage of dew harvester and fog catchers in Tanzania. These examples foresee the usage of both systems in rural areas and high altitudes which have higher humidity levels and lower temperature compared to city centres. There is no doubt that it will increase the efficiency as Amani tests revealed.

CONCLUSION The efficiency of dew harvesting is not comparable with rain water collection in terms of water amount. Maximum amount of water was collected by “bumps” surface (1m2) with the amount of 0.08 litres per night. Dew harvesting shouldn’t be thought as a main water source that supplies water for the whole household. Instead, it might be useful to consider it as an emergency or extra water source for the residences. It is a sustainable, cheap and easy way to generate water and the usage as a roof element has benefits on cooling. It’s usage in larger scales in rural areas could be more effective. Moreover the system could also directly serve for agriculture. To sum up, Tanzania in general, including its most populated city Dar es Salaam, is having major infrastructure problems; no access to electricity, very often power cuts in the places that has electricity infrastructure and lack of safe water and sanitation around the country. Any development in country’s infrastructure would be useful for the people living in Tanzania.

ACKNOWLEDGEMENTS I would like to thank Professor Kenneth Park and Professor Joanna Aizenberg from Harvard University Wyss Institute for all their support in surface designs. I would like to thank all my tutors David Garcia, Jakob Knudsen, Thomas Chevalier Bojstrup, Marianne Hansen and Emanuele Naboni and all the IBT researchers for their support in measurement techniques.

CONCLUSION

Dew Harvesting  

An Alternative Water Source for Tanzania

Dew Harvesting  

An Alternative Water Source for Tanzania

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