Memorandum on Initial Trial of Solar Bottle Bulb in Jorgen Babur Mart slum, Dinajpur, Bangladesh.

S. G. Stephens BE (Hons) June 2012

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MEMORANDUM ON INITIAL TRIAL OF SOLAR BOTTLE BULB IN JORGEN BABUR MART SLUM, DINAJPUR, BANGLADESH Prepared by S. G. Stephens 7th June 2012 for SAFE Bangladesh (NGO) Pictures and video by Marianne Keating

INTRODUCTION SAFE Bangladesh is a small NGO working primarily in the low-cost housing sector in North West Bangladesh. As part of their work improving quality of life through improved building techniques, SAFE has started to experiment with using water-filled plastic bottles to provide low-heat and electricity-free lighting.

OVERVIEW OF INTIAL TRIAL Intial trial bulb was installed 6th June 2012, at the house of local slum builder Delowar. As this was an initial trial, bulb was placed near wall where it would be less-effective but where it could be placed through a small section of rather tired corrugated iron (CI) sheet that could be easily replaced.

A 2L coke bottle was filled with a mix of boiled water and approximately 250ml of Clorox liquid bleach purchased in Dhaka. Bangladeshi bleach seems to be far weaker than the equivalent in the UK. The bottle of Clorox states an active ingredient (Sodium Hypochlorite) concentration of >5,25%. Taking the label at its word, the bottle bulb should contain approximately 6.5ml of Sodium Hypochlorite per liter.

The bulb was initially placed and sealed into a small 500x500 section (or 'patch') of CI sheet using McCoy General Purpose Acetoxy Silione Sealent purchased from a glaziers in Dinajpur. After curing, a hole was cut in the roofing CI sheet and the bottle and 'patch' sealed on top.

PHOTOS

Bottle and CI sheet 'patch' before sealing

Cutting hole in roofing sheet

S. G. Stephens BE (Hons) June 2012

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Sealing between patch and roof sheeting

Placement

INTIAL COST ESTIMATE

Intial Cost Estimate of Solar Bottle Bulb In Dinajpur, Bangladesh (June 2012) Item Silicone applicator gun Tin Shears

Cost BDT 400 BDT 100

2nd hand plastic bottle Silicone 280ml tube Bleach (1L 5.25% NaOCl) CI sheet 'patch'

BDT 10 BDT 250 BDT 210 BDT 500

No. Bulbs Cost/Item ignored ignored 1 2 4 10

BDT 10 BDT 125 BDT 53 BDT 50 BDT 238

238BDT/bulb is possibly too expensive for the Solar Bottle Bulb to be widely adopted in JBM slum.

The following areas could produce savings in the cost of each bulb; 1. Finding a cheaper silicone or sealant, possibly in bulk with a brush application. Important qualities for the sealent are; elastic, bonds to steel and plastic and resistant to water, sun and elevated temperatures.

2. Finding a cheaper and locally sourced bleach. 'Bleaching powder' was found in Dinajpur though this powder had only very week concentrations of Chlorine and was cut with an insoluble powder that would make the bulb ineffective. Bleach needs to be found with as little colouring as possible, the Clorox used in the test has a slight yellow tinge which coloured the bulb.

3. Using second hand CI sheet to form the patches. This was done for the initial test bulb though it is hard to discern a cost for such a second hand item and new CI sheet prices are used in the calculation above.

S. G. Stephens BE (Hons) June 2012

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RESULTS Once placed, the bulb was very bright and provided a large amount of light into the previously very dark room. Please refer to http://youtu.be/rlS17jVZ6s0 for a visual demonstration of effectiveness.

The installation will be monitored over the upcoming Bangladesh rainy-season to evaluate effectiveness and durability of sealing system used.

Room interior with Solar Bottle Bulb covered

Room interior with Solar Bottle Bulb un-covered

S. G. Stephens BE (Hons) June 2012

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COMPARISSON TO OTHER LIGHTING ALTERNATIVES CLEAR PLASTIC CI SHEET One strip or even a short section of clear plastic corrugated sheet provides large amounts of light into a room. A 7' sheet costs 700BDT which is approximately 1.5times the cost of the thick CI it replaces. So, this is not inordinately expensive yet there is not one house in the slum where this has been used.

Possible reasons for the clear plastic sheet not being adopted are; • Heat. A small, 1'x2' section of the plastic sheet was installed in a SAFE demonstration house and provided a lot of light though the owner complained about the heat. • Frailty and durability. The plastic sheeting is seen to be weaker than the CI sheet it replaces and is likely to get dirty.

Comparing cost; A 2'4" x 2'6" clear plastic corrugated sheet suitable to make a skylight costs about 233BDT which is comparable with the 238BDT it cost for the initial trial solar bottle bulb.

It is hoped that the cost of the bottle bulb can be significantly reduced and that it performs better that the plastic corrugated sheeting in terms of heat and durability therefore making the solar bottle bulb a viable alternative.

ELECTRIC BULB Almost all the houses in the slum use at least one electric bulb, sometimes through an illicit connection.

The electric bulb works at night while the solar bulb obviously won't. This disadvantage is somewhat mitigated by the fact that the electricity supply is very intermittent. During peak irrigation season, rural areas of Dinajpur can receive as little as a few hours of electricity each day while the sun shines almost perpetually.

Comparing cost; From a recent electricity bill, the current price of electricity in Dinajpur appears to be 4.2BDT/kWh (1/6th of the price in the UK).

Assuming a 50watt bulb is used for 6 hours each day;

0.060 Ă— 6â„Ž Ă— 4.2 = 1.512 â„Ž

At the initial solar bottle bulb cost of 238BDT, the payback period is about 5½months.

It is hoped that, by reducing the cost of the solar bottle bulb, the pay-back period can be reduced and the financial advantage increased.

The cost of a traditional tungsten filament bulb is only 22BDT. If we consider a 5watt energysaver bulb, the pay-back period jumps to over 5years. However, the initial cost of an energy saver bulb is approximately 250BDT and therefore more expensive than the solar bottle bulb. An energy-saver bulb will also be susceptible to the sporadic electricity supply.

S. G. Stephens BE (Hons) June 2012

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LESSONS LEARNED AND KNOWLEDGE GAINED 1. Bulb is effective yet expensive (≈240BDT). Steps described earlier in 'Initial Cost Estimate' could significantly decrease cost and improve likelihood of technique being adopted.

2. A cheaper and possibly simpler form of sealant needs to be found locally.

3. A cheaper and possibly 'clearer' bleach or disinfectant needs to be found locally.

4. Monitoring and experimentation is required to see which concentrations of which bleaches/disinfectants are most effective and affordable.

5. It is important to use good quality CI sheet for the patch as well as select a good piece of receiving CI sheet on the roof. This is because worn CI sheet can have a less-pronounced or deformed corrugation profile and therefore be difficult to seal.

6. It is important to center both the hole in the patch and the hole in the receiving sheet to the same orientation of the corrugations. i.e. a corrugation ridge should correspond to the centerline of both the hole in the patch and the receiving sheet.

7. Financial and other advantages of these bulbs are currently not very convincing to slum residents. Further study is required to produce a stronger case to submit as to "why?" they should install a solar bottle bulb.

LONG-TERM VISION It is hoped that one or more of the local Jorgen Babur Mart slum builders (Delowar, Masud or Baush) can be trained how to install solar light bottles and do so for a reasonable price while earning some money for themselves. In short, to create a small entrepreneurial business to provide improved lighting throughout the slum.