52
Inventory of Innovative Indoor Smoke
Alleviating Technologies in Nepal
concentrated radiation, thus higher temperature is
obtained. The absorbent surface is coated black to
absorb maximum radiation.
Box type solar cooker is a tray usually made up of black
coated aluminum sheet which is covered by transparent
glazing. Most of the box type solar cooker has a reflector
to increase the solar radiation on to the tray. Raw food
is loaded inside the tray in separate cooking pots.
A single-reflector box cooker is the advantage of slow
and even cooking for large quantities of food. Variations
include slanting the face toward the sun and the number
of reflectors. Such cooker usually tops out at around
150°C. A single-reflector box cooker takes about twice
the time to cook compared to a conventional oven. With
a single-reflector box cooker, once the food is cooked,
it just stays warm and doesn’t scorch.
Cooking with the parabolic cooker is similar to one
burner conventional stove. The concentrated sunlight
is directly reflected on the bottom of the pot. In this
type of solar cooker, higher temperature is obtained,
thus cooking time required is lower compared to box
type solar cooker. As there is a possibility of burning
food due to high temperature, food should be stirred at
regular interval. Typical parabolic type of solar cooker
(1.4 m in diameter and 28.6 kg) developed by CRT/N
takes 1 hour to boil 10 liters of water, 30 minutes to
cook 0.5 kg of rice and 45 minutes to cook chicken and
other meat items. Parabolic cookers must be tracked
every 10 to 30 minutes depending on the focal length
to obtain maximum solar radiation.
Allart Ligtenberg, an Engineering Manager started to
work on solar cooker in collaboration with CRT/N since
1992 and is recognised as the pioneer of solar cooker
in Nepal. The technology is further disseminated
through awareness, demonstration, food testing, pilot
projects, media exposure and the distribution of
informational handouts. Initially, Ligtenberg and CRT/N
sensitised and encouraged NGOs, community leaders,
environmentalists and scientists to send their
representatives to solar cooking workshops. Although
the momentum for the promotion and dissemination
of cooker in Nepal is in slow pace, it is quite
encouraging. CRT/Nepal has focused its promotion in
urban/semi urban and tourist areas. Nepal Government
provided partial subsidy for its promotion. So far, about
1000 units of SK 14 parabolic solar cooker is
disseminated in various parts of the country through
collaborative efforts with the government and other
various development partner organisations. CRT/N has
plans to promote 2500 solar cookers within next five
years alongside eco-tourism areas of Nepal. The use
of each solar cooker for 4 - 5 hours a day and seven
months a year can save about 2300 kg of fuel wood
yearly on an average.
Realising the usefulness of solar cooker and recent
increase in fuel price, Nepal government has provided
50 per cent (but not exceeding NRs. 4000) subsidy to
solar cookers (box type and SK 14 parabolic type) as
per policy on renewable energy subsidy delivery
mechanism.
Despite the high cost, there is a high potential for this
technology in Nepal because of average solar intensity
of about 4.7 KWh/m2/day (AEPC, UNEP/GEF 2006). With
increased cost of other energy sources and scarcity of
fuel wood, solar cookers can be the ultimate substitute
for cooking which is also a renewable source of energy
and is pollution free. The major organisations working
in solar cooking technology are:
Alternative Energy Promotion Center Nepal
(AEPC/ N)
Centre for Rural Technology Nepal (CRT/N)
Foundation for Sustainable Technology (FoST)
Kathmandu Environmental Education Project (KEEP)
Trekking Agencies Association Nepal (TAAN)
Gramin Urja Tatha Prabidhi Sewa Kendra (P) LTD
Solar Energy System (P.) Ltd
Krishna Grill and Engineering (P) LTD