INNOCENTIVE Solution

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Solution Submission Form

Solution Submission Form v2 | Innocentive 2005 | January 11, 2009

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Description of solution Storage System for Rainwater

Based on the Innocentive specification, the prices are calculated based on a currency for and $: 1,40 $ for 1,00 . All prices are wholesaling prices or ex factory for medium(500-1.000) pieces lot sizes. I have marked and calculated my top solution. But theconditions in developing countries are very different. So I have described and calculatesome alternative solution. It was nor asked for the collection system but I made somethoughts because you cannot be sure that you can design a collection system just withlocal material. Following the way of the water there will be the steps. So you have to findthe best (cheapest) solution for every step.

1.) Collecting the water from the roof (rain gutter)2.) Down pipe

3.)

Pipe from down pipe to reservoir4.) Filter5.) Reservoir and frame for stabilization6.) Water withdrawal7.) Extreme low cost / foil storage system

Problems around the system:

A) Overflow protectionB) Material choice for ReservoirC) Ultraviolet Resistance (UV-Resistance)

D)

Oxygen supply for stored waterE) Quite incoming water / clear outgoing water from surfaceF) TemperatureG) Mosquito and animal protectionH) Complete costs incl. transport and local workI) Bigger units and modular systems

Username:InnoCentive Challenge #: 7497318

InnoCentive Challenge Name: Low-cost Rainwater Storage System

Doc. Number: (internal use only)

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1) Collecting the water from the roof

Specification:Low costFor 10m of roof areaLength 5m (modular) and opportunity for cutting

Why thinking about rain gutter?Not every roof in developing countries has got a rain gutter so it is point of cost.

Dimensioning of the rain gutterMinimum diameter: 10m * 800 l/(1s 10000m) = 0,8 l/sFollowing (DIN EN 12056) there will be a minimum diameter of 50mm for nearly 100%storage volume during heavy rainfall.

Fixing material: You have to calculate 15% on top for simple fixing material (wire and/orcable straps, some nails, screws).

Solution 1: Iron rain gutter

Iron zincked 2,06 [ 2,88 $] per meterabout 5m are needed => 10,30 [14,40$]for one roof side

Conclusion: good working system but much too expensive.

Solution 2: Plastic rain gutter

Plastic (PVC) 1,70 [2,38 $] per meterabout 5m are needed => 8,50 [11,90$]for one roof side

Conclusion: good working system but also too expensive.

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Solution 3: Plastic Profile Standard (semi finished part) used as rain gutter

Plastic (PVC) 50mm x 50mm x 3mm1,35 [1,89 $] per meterabout 5m are needed => 6,75 [9,45$]for one roof side

Conclusion: working system but special parts like endings and connector to down pipeshave to be designed and to be produced. The reduction of costs in to less. So its better tobuy a Plastic rain gutting system.

Solution 4: Iron Fence with plastic foil inlay used as rain gutter [Second Best Solution]

Iron fenceMesh size 12,5mm x 12,5 mm (standard)55,20 per roll / 25m/roll / 2,5 strips = 0,88 /m [1,24 $/m]

Mesh size 25mm x 50mm (50% cost reduction) because of less material and machinehours. 0,44 /m [0,62 $/m]

fence with foil inlay

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Plastic foil (0,1mm): 0,001dm x 10dm x 2dm x 1,2 kg/dm3 x 2,5 per kg => 0,06 [0,08 $] per meter

about 5m are needed => 0,44 /m mesh0,06 /m foil

total: 0,50 /m x 5m = 2,50 [3,50 $] for one roof side.

Conclusion: cheapest system but it will need about 2h more time per roof side for fixing.

It could be necessary to repair the foil.

Solution 5: cut drainpipe (without holes) [ TOP Solution ]

Diameter 50mm 0,60 / m and 0,5 h more time to prepare (cutting) the drainpipe.about 5m + 1m are needed => 3,60 [5,04$]for one roof side(one more meter because of curved endings)Conclusion: good working system less expensive easy to fix and less risk of rapair.

Decision:Both systems cut drainpipe and fence with foil inlay are working low cost solutions.If low cost is top you have to take fence with foil, but in the long term run I think the cutdrainpipe will be better because of less risk of repair. The low cost systems are not 100%dense. They just have to collect an high amount of rainfall.

There is an option without rain gutter see (chapter 7), it is extreme cost reduced but itneeds very much working hours, maintenance and a relative high risk of repair andfailure.

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2) Down Pipe

Specification:Low costHeight: 3m maximum roof to ground (water storage level)

Connection between gutter and down pipe:There are several connectors for European and US to buy, but each is at least about 2,00 [2,80 $] Thats too much just for one connection. So I will describe some No cost

solutions.

Dimensioning down pipeSame diameter [50mm] like gutter

Fixing material: You have to calculate 15% on top (same as gutter).

Solution 1: Plastic waste water pipe DIN

Plastic Polypropylene 3,87 [ 5,42 $] per 3 meter

Conclusion: good working system but not the cheapest.

Solution 2: Drainpipe as down pipe

Plastic Polypropylene 1,80 [ 2,52 $] per 3 meter

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Conclusion: as good working system as waste Water pipe and just half the price.Fixing drainpipe at gutter (no cost solution):Down pipe and gutter are the same material. You just have to prepare the roof area and tocurve the pipe.

delivery condition cut and curved

Solution 3: Foil pipe(foil tube) ) [ TOP Solution ]

Principle of fire fighter tube , but just with thin plastic foil (0,1mm).

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Plastic foil (0,1mm): 0,001dm x 10dm x 1dm x 1,2 kg/dm3 x 0,90 per kg=> 0,011 [0,015 $] per meter.=> 0,033 [0,045 $] per 3 meter.

Conclusion: extremely cheap system. There is a risk of repair but if you take PVC youcan fix wholes by gluing or just change the tube. If there is a long way to the reservoir onground level you have to protect the tube with local material. So there could be cases,when it will be cheaper to use a drainpipe.

Fixing foil tube at gutter (no cost solution):

Cut the end of the tube (30 cm the middle) and make a node upside the gutter.

3. Pipe from down pipe to reservoir

Specification:Low costDistance: 5m from down pipe to reservoir

The best is to have no distance between down pipe and reservoir, but sometimes you needa different position for the reservoir.

You can use the same solution as for the down pipe. Changing materials between down

pipe and ground pipe should be avoided.

Plastic waste water pipes and drain pipes can be buried without any problems.

If you want to use the foil tube you have to make a protection frame with local material.See below for some solutions:

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=> 0,03 [0,04 $] per meter.=> 0,15 [0,21 $] per 5 meter.Local working time 15 min/meter

Remark: optionally it could be interesting to use a foil pipe for longer distance watertransportation because of the extreme low costs.

4) Filter

There are several filter systems available. High-Tech Filters with good cleaning results

and no maintenance like hydraulic jump filters or filter collectors. But the prices are notacceptable 97,50 (reseller price) for hydraulic jump filter or 89,00 for filter collector.

Hydraulic Jump Filter (Diameter 100mm)

As water flows over a stone, its surface is smoothed, rounded and the waterflow issubstantially changed by the height drop, from a sub-critical to a super-critical flow. Atthe bottom of the dip, the waterflow changes again to a sub-critical flow in a process nowcommonly known as hydraulic jump This resulting increase in water power is similar to a

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strong eddy and any impurities are then forced over the next level and washed awaydownstream.

Filter collector

Filters directly in the down pipe:The construction of the vertically placed fine filter washes out large and small dirt (largerthan 0.28 mm). Moss, leaves and insects are automatically removed.

There are also various medium priced filtration systems

22,02 [30,82$] 36,48 [51,02$] 14,22 [19,91 $] 79,00 [110,60$]

But it is still to expensive. If you want to have a less budget solution you have to accept aminimum of maintenance and you have to use easy standard parts. No filtration will notwork, because the waste is collected at the ground of the storage system . Then non

oxygen microbes will make the water uneatable.

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To make a real low budget filter with an optimum of filtration quality you have to use asmuch standard parts as possible. Therefore for the case I used standard waste water pipesand connectors (HT-Rohr DIN). European rainwater systems do not accept anymaintenance.But in developing countries the time for getting water is high and a minimum of regularmaintenance will o.k.

The optimum filtration material will be a nylon tube. It is the same material as for ladiesstockings; just cheaper. But of course you can also use real lady stockings, soreplacement will be no problem.

Waste water Pipe Fitting and Nylon Stocking Filter

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The best position of the filter is in the down pipe. Both favourite down pipes are flexible(drain pipe and foil tube) so the filter could be removed very easily. The double collar iswithout rubber rings. Cleaning the nylon filter will be very easy just by removing thedouble collar. There is filter grid in the top to catch bigger parts. The overflow is just thecase of emergency if you forgot to clean the nylon filter. It should not be connected withthe central overflow. So you will immediately see if the filter is not working.

The prices are as follows (all prices are checked wholesaling prices) The grid have to be

manufactured. If you buy more than 20.000 parts a price of 0,15 per piece is possible.More will be cheaper of course.

Pricing of single parts of the filter:

1) Branch 1,59 2,23 $2) Grid 0,15 0,21 $3) Double Collar 1,26 1,76 $4) Rubber Ring 0,30 0,42 $5) Nylon Filter 0,41 0,57 $6) Central Pipe 1,74 2,44 $

7) Grid 0,15 0,21 $8) Reduction 0,78 1,09 $

Total 6,48 9,07 $

50% of the cheapest product you can buy but the same quality and amount of water as thehigh end filters. The assembly time will be about 15 min. It is not difficult so you can doit in the target country to reduce costs.

You can save some more money, if you design your own case. Then you can make No.1,2,3 as one part and No. 6,7,8 as one part. If the number of parts will be o.k. you can

reduce the price down to 4,50 [ 6,30 $] per unit

Sand filterShown at the extreme low cost solution (see chapter 7) I used a sand filter. It is verycheap. You only need a few square meters of foil and a little sand. But it will needmaintenance (cleaning the sand several times) and it needs place near by the wall.

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5. Reservoir

The classic storage systems for rainwater are plastic tanks. But weight, volume, costs andtransportation is not acceptable. See examples below.

Schtz 120 [168$] 600liter Intewa 260 [364$] 1100 liter Graf 27 [38 $] 500 liter

Solution 1: Blow out storage system

Based on children wading pools you I have designed a reservoir you can blow out. Sothere will be a minimum of storage room during transportation and a very light design.

200 liter 4,91 2.000 liter 16,40 cover foil 1,70

blow out storage for rainwater:If you want to use the shown system for rainwater, you will need a higher geometry and

some flat areas, where you can make holes for pipes. So a 500 l blow out storage systemcould have the following design:

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all dimensions [mm]

The calculation of costs will be not easy. I think twice the price of the 200 literwading pool will be a first realistic mark. So you have pay about 9,82 [13,75 $]forthe reservoir plus cover foil 1,70 [2,38 $].

Conclusion: it will be a working solution, but there will be high costs for design andtesting. Because of the option to repair you have to use PVC. So you have to produce

a large quantity to hold the prices. There will be some problems on top which does notexist for leisure use. The live time has to be much longer. For example you have useultraviolet resistant foils. It will be better to use a multi air chamber system to avoid acomplete failure of the system.The price is o.k. but not really cheap.

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Solution 2: Big Bag with foil inlay (TOP one)

For transportation of sand in the building construction industry big bags are verycommon. Youalso can transport liquids with big bags, if you have a foil inlay bag. If the number ofpieces (1000and more) is o.k. you can get every dimension you want for the same price. Theoutside is bright

and UV-stabilized.

foil inlay big bag examples for big bags

Based on this idea a have designed a rainwater storage big bag. It is a 6-corner (near bycircle) with long straps to hold stabilisation pipes. So you can have very light and goodfor transportation solution. As inlay I took one with just one hole in the top. So the riskof pollution and unwanted animals (insects) is minimised. Overflow and waterwithdrawal is no problem(see chapter 6 and A)

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The stabilisation pipes are working like a tent.

Big-bag offer (500 liter bag):not glued inside and outside bag; 5.000 pieces 4,05 [5,67 $]The pricing is for a 4 corner bag with straps on top. There will be no difference ifthe straps are at the side and if there will be 6 corners, but therefore are realproject is needed.

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Stabilisation pipes:Plastic pipe (20mm diameter; 1mm thickness; 1200mm length ):

3,14 x 0,2dm x 0,01dm x 12dm x 1,2 kg/dm x 0,90 per kg = 0,08 [0,11 $]Connector pipe (18mm diameter; 1mm thickness; 411mm length ):3,14 x 0,18dm x 0,01dm x 4,11dm x 1,2 kg/dm x 0,90 per kg = 0,03 [0,04 $]

Pricing of single parts Big-Bag reservoir:

Price per Unit Units Total

1) Outside Bag 4,05 1 piece 4,05 5,67 $2) Inside Bag incl. 1 piece - -3) Pipe 1200mm 0,08 6 pieces 0,48 0,67 $4) Pipe 411 mm 0,03 6 pieces 0,18 0,25 $

Total 4,71 6,59 $

Conclusion: it will be a good working solution and my top one, using a proofedsystem for transportation in the building construction industry. The inlay foil bag is

not 100% leak proof just 99,99999%. That depends on the weldseam. But the leaks arenot going bigger. It is just like sweating a few drops per day. This is acceptable.There are two options for the positioning of the bag: downside in earth like seen inchapter 7 or on the ground. You can save a little bit of costs (stabilisation pipes) butthis is not a real advantage. The real advantage is the cold and lightless storage. Butthe work to make the whole in hard ground makes it sometimes easier to deposit thereservoir at the surface. If you will put the reservoir inside earth you also have to dig ahole for water withdrawal which needs time and local material.

6. Water Withdrawal

You have to make a hole downside the reservoir an to fix a connector at the foil for thetube. At first you think it will be the easiest to fix the connector by gluing or melting.Gluing (only PVC) with local workers you take the risk of leaking. But you have to do itwith developed country man power so you have to pay at least 1,00 [1,40$] for fixing.The second problem is the position of the hole. There will be no chance to change theposition.

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glued tube connector

The thinner the foil is the bigger the diameter of the flange has to be.

The diameter tube can be minimal. There will be time wait a minute to fill up the waterso I have taken a diameter of 1/2 .

It will be much more easy to make a hole into the foil and to fasten the connector withscrews.

Connector with screws (hose nipple not shown)

There are some systems with winding but they will not work with thin foil.

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Valve: there are many valves to open and to close the reservoir. But the cheapest one willbe no valve. After the connector will follow a tube of about 1,5 m. If you need water youjust put the tube downside and the water will flow. If you do not need water the tube willbe fasten upside and the water stops. You can put a little bit of fabric to protect againstpollution and insects. Best you take a clear tube so you can see how much water is insidethe reservoir from outside (similar to Pitot tube).

No-valve system

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Pricing of withdrawal screw version :


1) Tube Connector 1,20 1 piece 1,20 1,68 $2) Tube Sheetl 0,20 1 piece 0,20 0,28 $

3) Rubber Seal 0,09 1 piece 0,09 0,13 $4) Screw 0,02 4 pieces 0,08 0,11 $5) Tube 0,63 / m 1,5 m 0,95 1,33 $6) Hose Clip 0,16 1 piece 0,16 0,22 $

Total 2,68 3,75 $

With glued connectors you can save 0,37 [0,52 $] of material but you have to solve theproblem of local gluing. So I have calculated the saver solution.

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7.) Extreme low cost / foil storage system

If there is enough place around the building, not extremely hard ground, you can storeand filter (with no extra costs). You just have to make a double fosse along the roof.

The prices are as follows (all prices are checked wholesaling prices). The thickness of thefoil has a main influence of the costs. If you check the ground for sharp pieces before

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fitting the foil it will be possible to take 0,25 mm foil. Because of the option to repair Iwould prefer PVC foil.

Example for PVC-foil for garden ponds. Price for 0,5 mm incl. tax and no resellerdiscount. Without tax and incl. wholesale for 0,2mm:

Plastic foil (0,25mm):0,0025dm x 10dm x 10dm x 1,2 kg/dm3 x 0,90 per kg = 0,28 /m [0,39 /m]

Pricing of single parts of the foil storage system:Total Total

Price per Unit Units Storage Filtration

1) Reservoir Foil per m 0,28 2,4m x 6m= 14,4m 3,23 0,65 2) Sand Bed local material - -3) Plank local material like bamboo or boughs - -4) Cover Foil [0,12mm] per m: 0,14 1,5m x 6m= 9,0m 1,26 -5) Overflow with fence 0,41 + 0,15 3 pieces - 1,68 6) Straw local material - -

Total 4,49 2,33

There is no special training necessary so. So you just need 2 x 8 h of your own local work

to fix the whole system.

Resumee:It is not much cheaper than the Big Bag solution, but it has got an extremely low costfiltration system and it needs no rain gutter. If you have a hard ground or not enoughspace in front of the house it will be difficult to realize this solution.

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A) Overflow Protection

The cheapest way for overflow protection is no overflow protection. You just make adent at the top of the storage system and let the water flow. If it is wanted you canmake a small channel to give the water a defined direction [similar to ground pipe].But you will have a muddy area. With a minimum of costs you can make a connectorfor overflow if foil is used for storage. Just make a smaller hole than the tube andpress and fix it with a hose clip. I have used this system downside 2m deep 24h underwater for 10 years without any leaking. But you have to make several tests with the

diameters and the material so this solution is for local workers only acceptable asoverflow protection.

fixing overflow protection

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Pricing of overflow protection:


5) Tube 1 1,02 / m 0,15 m 0,15 0,21 $6) Cable Clip 0,02 1 piece 0,02 0,02 $

Total 0,17 0,23 $

You can add drainpipes of foil tubes at the end. The length depends on the localsituation so you cannot make any pricing. For prices per meter see chapter groundpipe.

B) Material choice for reservoir

Generally you can use vinyl plastic like polyvinychloride (PVC) or vinyl free plasticlike Polyethylen (PE). The price is in the long term run is a little bit better for PVC.Recycling is easier for PE, but it is much more difficult to repair PE for not qualifiedworkers.

So if there will be a risk of failure or leaking I would prefer PVC. If there is no risk offailure would prefer PE.

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For the calculation for easy part like foils I have taken the commodity pricemultiplied with the factor 2,0 . this means for PVC 0,90 / kg and for PE 1,10 /

kg.

C) Ultraviolet Resistance (UV-Resistance)

For long term use (several years) it will be important that the sunlight will notdestroy the storage system. If the storage box is covered with something (straw) itwill be no problem.There are some foils with optimised UV-Resistance, but this is no resistance for100 years.

So the extra costs of the better material have to be calculated on top.A solution could be coating the foil but it has to be a very low budget paint. Youcan use a bitumen paint. There will be good connection between foil and paint.But you have to be careful that there will be no paint inside the water because ofthe pollution and bitumen colour need a very long drytime. So the best will be tocover the foil with earth and straw or other local material. Only in the case ofemergency you can use a bitumen colouring.

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D) Oxygen supply for stored water

There has to be a permanent exchange of air at the surface of the water. Otherwisethere will grow anaerobe microbes which are smelling bad. During short time theywill makes the water uneatable. In tropic areas this effect could be faster thanwanted. So you have to guarantee a circulation of air around the surface of thewater.

Solar ventilation:

You will need two openings for air conditioning In and out. To guarantee movingair you will usually use an electrical van. In our case this will be much toexpensive. So I will use the effect, that warm air is going up. Ingoing Air willcome from the overflow opening and the outgoing air will end into a black tubelike a smoke pipe. Because of the black colour the air is getting hot and goingupside. The hot air is made outside the reservoir so temperature will not be aproblem.

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Costs of solar ventilation:


1) Black Drain Tube 0,25 / m 1,5 m 0,38 0,53 $2) Hose Clip 0,16 1 piece 0,16 0,22 $

Total 0,44 0,75 $

Resumee: Because of the minimum of costs you should ad the solar ventilation toenlarge the storage time.

E) Quite incoming water / clear outgoing water from surface

If there is only a open pipe for the incoming water there will be much turbulence inthe storage and small pollution on the ground of the reservoir in moving around dropsdown the quality of the water. To avoid this effect put one meter of foil pipe (chapterground pipes) at the end of the incoming pipe and fix it with a hose clip. So thewater is running through the foil pipe and slowed down and the turbulence isminimized.

The best quality of water is a few cm down from surface. To get this water bywithdrawal you substitute the one ending connecter by an double ending connectorand a thin flexible tube of 1m inside the reservoir. At the end of the tube you fix asmall block of Styrofoam so the end of the tube will swim near the surface.Costs of incoming and outgoing water optimising:


1) Flexible Tube 0,46 / m 1,0 m 0,46 0,64 $2) Hose Clip 0,16 1 piece 0,16 0,22 $3) Styrofoam 0,02 1 piece 0,02 0,02 $

4) Cable Clip 1 0,02 1 piece 0,02 0,028 $5) Foil Tube 0,011 / m 1 ,0 m 0,011 0,015 $

Total 0,67 0,94 $

Resume: You should invest this money to get a better quality of water. The budget20$ is still o.k.

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F)Temperature

The colder the water will be the longer it will stay eatable. So the best storage is inearth an on top covered with e.g. straw for isolation. If there is no opportunity to storethe water downside you have to chose a bright surface a shadowed place for thestorage. It could be a problem if a UV-protection colouring is done because it will bein black because of costs.So you have to use a very thin white foil on top which has to be changed whendestroyed by sunlight. Another opportunity the isolate the water is also using strawfor upside reservoirs.

You can use bales of straw or you can use a thin cover bag (about 1,5 [2,1$] )around the storage big bag or blow out storage and fill it with straw. So you canreduce the warming of the water during the daytime.

G) Mosquito and animal protection

Because of the aircondition it you are forced to have at least two openings for air.Generally animals could come inside the reservoir through the openings. But it is easyto make this openings animal save just by taping a rest of the nylon filter materialin front of the air tubes.

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H) Complete costs incl. transport and local work

There was a limit of 20$ for basic storage system:

The calculation of my favourite (not cheapest) solution big bag stand alone atgroundis shown below:

1) Reservoir 4,71 6,59 $

2) Water withdrawal 2,68 3,75 $3) Overflow protection 0,17 0,23 $4*) Quite incoming

outgoing from surface 0,67 (0,94 $)5*) Solar Ventilation 0,44 (0,75 $)

Total I 8,76 12,26 $

6) Local Work (5h with minimum skilled worker) 0,89 1,25 $7) 20% for extra parts 1,75 2,45 $(I think it will be less, because of detailed calculated solution)

8) Transportation (10 kg ) volume minimal0,06 $ t km * 3.000 km* 0,01 t = 1,28 1,80 $3000 km because of special plastic parts

Total II 12,68 17,76 $*) not necessary but very usefuland calculated

Added systems and parts:

A) Filtration 4,50 6,30 $

B) water collection and piping see first chapters

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S l ti S b i i F 2 | I ti 2005 | J 11 2009

I) Bigger units and modular systems

500 liter is a very small unit for water storage connecting such small units via pipesand tubes will not be the optimal way. I think you should design a larger unit about2.000 liter (European common size for restroom use) . The cost will be less thandouble from the 500 liter and you will have four times more volume. If you arelooking for larger than 2.000 liter units you can connect two ore more 2.000 liter unitswith pipes and tubes.

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INNOCENTIVE Solution

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