Information about:

TUKIMARA- WLED base domestic lighting in rural Nepal.

Background
Expensive and inefficient incandescent lamps are being replaced by the fluorescent lamps.  Tube Fluorescent lamps ad the compact fluorescent lamps are the most popular fluorescent lamps used in trural Nepal. However these lamps also have shortcomings

  1. Uncertain lifetime
  2. Cheap electronics ballast causes harmonics.
  3. End blackening
  4. Low cost Chinese lamps are not durable and d not have certain lifetime. Sometimes they blow up in few seconds.
  5. A good CFL may cost thousand rupees to buy. (NRs. 800 for a CFL manufactured but National company)
  6. Needs periodic cleaning and there is a high risk of breakage of glass while cleaning
  7. Smoke deposition reduces the considerable amount of light output (almost 33%).

 

In order to reduce these problems Center for Renewable Energy (CRE) Kathmandu, Nepal has undertaken an adaptive research for the development of suitable electric lamps and accessories under RETs-in-Asia Project (Phase II).   This project is funded by the Swedish International Development Cooperation Agency (SIDA) and managed by the Asian Institute of Technology (AIT), Bangkok, Thailand.

Introduction
Tukimara is a combination of two Nepali words (TUKI=a kerosene lamp/wicked lamp. Mara=to kill) so it implies that it kills the kerosene lamp.  Tukimara is a white LED base lighting system developed for the use in rural Nepal.

A tukimara lighting system consists of two units of white light based lamps and a small solar PV module.  These lamps are made with the cluster of three White Light Emitting Diode WLEDs.  These LEDs are durable and efficient.  A TM lamp consume only about 0.3W of electrical power with sufficient amount of lights.  A study done by CRE and Institute of Engineering, Tribhuvan University shows that the TM lamps produces 275 lux at a distance of 30cm which is 9.5 times higher than that of kerosene lamps lux output measured at the similar distance.

A socket is provided so that a portable transistor radio can be also be connected to the Tukimara.

Tukimara
Picture 1. TUKIMARA portable WLED lamp Picture 2. A girl reading under the Tukimara lamp[2]

The lamps can be used as table lamp (Figure 2) or wall mount lamp or a torch light. Small 3 V operated battery-less radio can be directly connected to the lamps.

WLED based lighting system is a alternative solution to the above mentioned shortcoming since thy possess the following characteristics

  1. They are literally maintenance free
  2. Consume considerably less power.
  3. Has a long lifetime (100, 000 hours).
  4. Strong epoxy resin on its outer surface makes it unbreakable
  5. Easy to clean
  6. Any renewable energy source like solar, wind, pico hydro can power or recharge the lamp.
  7. Even a human pedal power can be used to recharge the lamp.
  8. Easy o transport even to an extreme rural Nepal like Humla

Advantages of White LED Based Lamp sets.

  1. Smoke free. So more popular among womens.
  2. Can also be used as torch light
  3. Does not produce harmonics and electrical noise so there are no electrical interferefnces.
  4. Hard epoxy resin surface makes it unbreakable even in the harsh environment.
  5. Its more reliable since very less electronic components are used.
  6. Doesn’t require frequent recharging.
  7. Recharging is quite simple even with 1W solar PV module, bicycle dynamo, pelton water turbine, or human operated pedal power pack.
  8. Not risky even if handled by children since there is little chance of fire-outbreak.
  9. Suitable for Hotels and Restaurants in rural Nepal.

Batteries
Nickel cadmium and nickel Metal Hydride batteries are used commonly to power TUKIMARA.  Nickel metal hydride are costlier that Nickel cadmium however it has few advantages over Nickel Cadmium

  1. Its lifecycle is higher; consequently cost per hour of lifetime is less.
  2. It doesn’t have memory effect so can be recharged without discharging it completely.
  3. Lighter in weight compared to other similar rechargeable batteries.
  4. Perform well in cold climate.
  5. Environmentally friendly.

III. COST
The initial cost of the system as well as the operating cost plays a deciding role when new technology is introduced to replace the current technology. The TM is primarily intended to displace the traditional kerosene lamps from the rural areas. An analysis has indicated that the money spent over two years on kerosene (for two lamps burning around 4-5 hours daily) and dry-cells to operate radio and torch light is almost sufficient to buy a TM system without any subsidy.

At present condition the cost of the TM lamps cost NRs. 3000 (US $ 40.00).  The operating cost for the TM lamp is about NRs. 300 (US $ 4.00).  These costs are valid only if the TM are manufactures in a small scale.  The cost could be considerably reduced if they are manufactured in a large scale.

This amount is similar to the amount spent on a kerosene lamp over two years (two lamps burning around 4-5 hours daily) and a dry cell to run radio and torch light.

Conclusion
An advent of WLED lamps has opened the opportunity fopr the more durable, efficient and environmentally friendly lighting system for rural Nepal.  Thought the initial cost of the WLED lamps might be higher it has a much more long term benefits over traditional and inefficient lighting system.

 

References
www.retsasia.ait.ac.th/Publications/WRERC%202005/CRE.pdf