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(Constructional Features: Corrected or simplified some of the confusing sentences. Also minor grammatical issues.)
 
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[[Image:Low_cost_wooden_solar_box_cooker_open.jpg|left|350px]]
 
[[Image:Low_cost_wooden_solar_box_cooker_open.jpg|left|350px]]
In this design by [[Sankha Subhra Datta]] an attempt is made to reduce the cost of a conventional box type cooker. The cooker is very appropriate for rural applications. Fabrication of the cooker is very easy and so cost of labour is also lowered down. This cooker can be built by semiskilled village artisans by using simple hand tools and with locally available raw materials.
+
In this design by [[Sankha Subhra Datta]] an attempt is made to reduce the cost of a conventional box type cooker. The cooker is very appropriate for rural applications. Its easy construction reduces cost of labor, and allows it to be built by semiskilled village artisans by using simple hand tools and with locally available raw materials.
   
 
==Instructions==
 
==Instructions==
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=== Constructional Features ===
 
=== Constructional Features ===
 
The detailed constructional feature of the cooker is shown in Figures. The top open cooker
 
The detailed constructional feature of the cooker is shown in Figures. The top open cooker
box is made of half inch thick wooden box. Inside surface of the cooker box is covered by
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box is made of a half inch thick wooden box. The inner sides and bottom of the cooker box are covered with
aluminium foil in all sides and bottom to direct solar radiation towards the cooking pots. Fil is
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aluminium foil to direct solar radiation towards the cooking pots. The foil is
pinned with wooden box. For reflecting surface, the wooden cooker box will not be able to
+
pinned to the wooden box. Because of this reflecting surface, the wooden cooker box itself will not absorb radiant heat. Also, there is not much heat loss due to conduction from the foil to the wooden box, wood being a poor conductor. So, most of
absorb radiant heat. Heat will be transferred to cooker box only through the conduction
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the absorbed heat is retained in the cooking pots. The Cooking pots should not be direct contact with the foil to avoid damage to the foil; rather these are to be kept on pot stands
process from aluminium foil but foil will not be able to transfer heat much as thin foil itself will
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(common ring shaped stands made of steel wire available in utensil shops). A slotted seat is
absorb heat only from entrapped hot air and wood is not at all a good conductor. So, most of
+
provided near the top of cooker box for cover glazing made of 3mm
the absorbed heat will be retained in cooking pots only. Cooking pots should not be directly
 
in touch with foil to avoid damage of the foil; rather these are to be kept on pot stands
 
(common ring shaped stands made of steel wire available in utensil shops). Slotted seat is
 
provided near the top of cooker box for cover glazing. Single cover glazing made of 3mm
 
 
thick transparent window glass. Cooking pots are to be placed side by side inside of the
 
thick transparent window glass. Cooking pots are to be placed side by side inside of the
cooker by opening hinged glass cover as usual. South facing booster reflector is hinged with
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cooker by opening the hinged glass cover. A south facing booster reflector is hinged with
the wooden cooker box. Frame of the glass cover is made from Lg. sheet. Booster Reflector
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the wooden cooker box. The frame of the glass cover is made from GI (galvanized iron) sheet. The Booster Reflector
is fabricated by fixing mirror glass on G.I sheet frame. Reflector can be adjusted in desired
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is made by fixing mirror glass on a GI sheet frame. The reflector can be tilted to desired
inclination through the adjustment of stays. To make leak proof joint in between wooden
+
inclination by adjusting the stays provided for the purpose. To make a leak proof joint in between wooden
seating and closed cover glazing, nylon rubber pieces cut from old tube of motorcar tire is
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seating and closed cover glazing, pieces cut from an old car tube are used as gasket material. For proper seating of the gasket, small grooves may be cut at the
used as gasket material. For proper setting of gasket, small grooves may be cut at the
+
top of the wooden box seating. The gasket is also used inside of metallic channels of the cover
topside of the wooden box seating. Gasket is also used inside of metallic channels of cover
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glazing for sealing the glass pane. Gaskets are attached using an epoxy adhesive. The cooker measures 18 inch x 12 inch x 6 inch. The length of the
glazing for sealing of glass pans. Epoxy adhesive is used in addition for fixing gasket in all
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cooker, greater than its width is designed to increase the time between reorientations.
the joints. Dimensions of the cooker box are 18inch x 12inch x 6 inches. Length of the
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The diameter and the height of the two aluminium cooking pots are 5 inch and 3.2 inch respectively.
cooker, greater than its width is designed to increase the time gap in between reorientations.
+
Cooking pots are painted dull black using an automobile muffler paint.
Diameter and height of the two aluminium cooking pots are 5inch and 3.2inch respectively.
 
Cooking pots are painted dull black by automobile muffler paint.
 
   
 
=== Test Results ===
 
=== Test Results ===
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* Time taken for cooking 0.5kg of rice (weight after preparation): 2hrs 15min.
 
* Time taken for cooking 0.5kg of rice (weight after preparation): 2hrs 15min.
 
* Method of cooking- One part of rice mixed with water twice of rice volume and then placed in cooker.
 
* Method of cooking- One part of rice mixed with water twice of rice volume and then placed in cooker.
* Time taken for cooking 200gm Dal (lintel soup): 2hrs 30min.
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* Time taken for cooking 200gm Dal (lentil soup): 2hrs 30min.
 
* Method of cooking- One part of Dal mixed with water (twice the volume of Dal) and then placed in cooker.
 
* Method of cooking- One part of Dal mixed with water (twice the volume of Dal) and then placed in cooker.
* Time taken for cooking boiled potato (2nos): 2hrs 30min.
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* Time taken for boiling two potatoes: 2hrs 30min.
* Method of cooking- Potatoes are cut into pieces and cleaned with water and then placed in cooking pot without adding of water. Wet surface of potato after water cleaning is sufficient for preparation of potato. Potato rather will not boil if water is added in the pot.
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* Method of cooking- Potatoes are diced and cleaned with water and then placed in cooking pot without adding water. The wet surface of potato after water cleaning is sufficient for preparation of potato. Potato rather will not boil if water is added in the pot.
* Test of prepared food: Good
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* Taste of prepared food: Good
   
 
<h3>Approximate Cost Estimation (for prototype making)</h3>
 
<h3>Approximate Cost Estimation (for prototype making)</h3>
   
<table data-rte-empty-lines-before="1"><tr>
+
<(Say, Rs.800 in Indian currency)>Rs. 790<table data-rte-empty-lines-before="1"><tr>
 
<td data-rte-spaces-before="1">1.</td><td data-rte-short-row-markup="true">Wooden for cooker box-</td><td data-rte-short-row-markup="true">Rs.70</td>
 
<td data-rte-spaces-before="1">1.</td><td data-rte-short-row-markup="true">Wooden for cooker box-</td><td data-rte-short-row-markup="true">Rs.70</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td data-rte-spaces-before="1">2.</td><td data-rte-short-row-markup="true" data-rte-spaces-after-last-cell="1" data-rte-spaces-before="1">G.I sheet, 2ft x 2ft, for cover glass frame and reflector back: \\(sheet for reflector back support and for frame of cover glazing)</td><td data-rte-short-row-markup="true" data-rte-spaces-after-last-cell="1" data-rte-spaces-before="1">Rs.60</td>
+
<td data-rte-spaces-before="1">2.</td><td data-rte-short-row-markup="true" data-rte-spaces-after-last-cell="1" data-rte-spaces-before="1">GI sheet, 2ft x 2ft, for cover glass frame and reflector back: \\(sheet for reflector back support and for frame of cover glazing)</td><td data-rte-short-row-markup="true" data-rte-spaces-after-last-cell="1" data-rte-spaces-before="1">Rs.60</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td data-rte-spaces-before="1">3.</td><td data-rte-short-row-markup="true" data-rte-spaces-after-last-cell="1" data-rte-spaces-before="1">Aluminium pot- 2Nos. -</td><td data-rte-short-row-markup="true" data-rte-spaces-before="1">Rs.80</td>
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<td data-rte-spaces-before="1">3.</td><td data-rte-short-row-markup="true" data-rte-spaces-after-last-cell="1" data-rte-spaces-before="1">Two Aluminium pots</td><td data-rte-short-row-markup="true" data-rte-spaces-before="1">Rs.80</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td data-rte-spaces-before="1">4.</td><td data-rte-short-row-markup="true" data-rte-spaces-after-last-cell="1" data-rte-spaces-before="1">Pot stands-</td><td data-rte-short-row-markup="true" data-rte-spaces-before="1">Rs.40</td>
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<td data-rte-spaces-before="1">4.</td><td data-rte-short-row-markup="true" data-rte-spaces-after-last-cell="1" data-rte-spaces-before="1">Two pot stands</td><td data-rte-short-row-markup="true" data-rte-spaces-before="1">Rs.40</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
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</tr>
 
</tr>
 
<tr>
 
<tr>
<td data-rte-spaces-before="1">11.</td><td data-rte-short-row-markup="true" data-rte-spaces-after-last-cell="1" data-rte-spaces-before="1">Overall Fabrication charge (cost of labour)-</td><td data-rte-short-row-markup="true" data-rte-spaces-before="1">Rs.200</td>
+
<td data-rte-spaces-before="1">11.</td><td data-rte-short-row-markup="true" data-rte-spaces-after-last-cell="1" data-rte-spaces-before="1">Overall labor cost</td><td data-rte-short-row-markup="true" data-rte-spaces-before="1">Rs.200</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
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</table>
 
</table>
   
===Machineries Used for Fabrication===
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===Tools Used===
   
 
Hand Saw, Hand Drill, Hand Shear, Rubber and Wooden Mallets, Pliers, Screwdriver Set, Wrench Set, Measuring Tape etc.
 
Hand Saw, Hand Drill, Hand Shear, Rubber and Wooden Mallets, Pliers, Screwdriver Set, Wrench Set, Measuring Tape etc.
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===Manpower Requirement===
 
===Manpower Requirement===
   
* Carpenter: For making wooden cooker box- 1 head for 2hrs.
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* Carpenter: For making wooden cooker box -- one person, 2 hours.
* Sheet metal worker for glass cover frame and reflector frame making- 1 head for 3hrs.
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* Sheet metal worker for glass cover frame and reflector frame making -- one person, 3 hours.
* Tin smith for soft soldering of joints at corners of glass cover frame and relector frame- 1 head for one hour.
+
* Tin smith for soft soldering of joints at corners of glass cover frame and relector frame -- one person, 1 hour.
* Fitter for final assembly work- - 1 head for 2hrs.
+
* Fitter for final assembly work -- 1 person, 2 hours.
   
 
==See also==
 
==See also==
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[[Category:Solar cooker designs]]
 
[[Category:Solar cooker designs]]
 
[[Category:Solar cooker plans]]
 
[[Category:Solar cooker plans]]
[[Category:Box cooker plans]]
 
 
[[Category:India]]
 
[[Category:India]]
 
[[Category:West Bengal]]
 
[[Category:West Bengal]]
 
[[Category:Solar box cooker designs]]
 
[[Category:Solar box cooker designs]]
  +
[[Category:Solar box cooker plans]]

Latest revision as of 17:27, February 14, 2015


Last updated: 22 May 2013      
Low cost wooden solar box cooker open

In this design by Sankha Subhra Datta an attempt is made to reduce the cost of a conventional box type cooker. The cooker is very appropriate for rural applications. Its easy construction reduces cost of labor, and allows it to be built by semiskilled village artisans by using simple hand tools and with locally available raw materials.

InstructionsEdit

Constructional Features Edit

The detailed constructional feature of the cooker is shown in Figures. The top open cooker box is made of a half inch thick wooden box. The inner sides and bottom of the cooker box are covered with aluminium foil to direct solar radiation towards the cooking pots. The foil is pinned to the wooden box. Because of this reflecting surface, the wooden cooker box itself will not absorb radiant heat. Also, there is not much heat loss due to conduction from the foil to the wooden box, wood being a poor conductor. So, most of the absorbed heat is retained in the cooking pots. The Cooking pots should not be direct contact with the foil to avoid damage to the foil; rather these are to be kept on pot stands (common ring shaped stands made of steel wire available in utensil shops). A slotted seat is provided near the top of cooker box for cover glazing made of 3mm thick transparent window glass. Cooking pots are to be placed side by side inside of the cooker by opening the hinged glass cover. A south facing booster reflector is hinged with the wooden cooker box. The frame of the glass cover is made from GI (galvanized iron) sheet. The Booster Reflector is made by fixing mirror glass on a GI sheet frame. The reflector can be tilted to desired inclination by adjusting the stays provided for the purpose. To make a leak proof joint in between wooden seating and closed cover glazing, pieces cut from an old car tube are used as gasket material. For proper seating of the gasket, small grooves may be cut at the top of the wooden box seating. The gasket is also used inside of metallic channels of the cover glazing for sealing the glass pane. Gaskets are attached using an epoxy adhesive. The cooker measures 18 inch x 12 inch x 6 inch. The length of the cooker, greater than its width is designed to increase the time between reorientations. The diameter and the height of the two aluminium cooking pots are 5 inch and 3.2 inch respectively. Cooking pots are painted dull black using an automobile muffler paint.

Test Results Edit

  • Intensity of solar radiation: 0.6 KW per sq.mt
  • Reorientation is done in every 30 minutes interval.
  • Ambient temperature: 28 degree Celsius
  • Peak temperature of empty cooking pot lid: 130 degree Celsius.

Cooking performance:Edit

  • Time taken for cooking 0.5kg of rice (weight after preparation): 2hrs 15min.
  • Method of cooking- One part of rice mixed with water twice of rice volume and then placed in cooker.
  • Time taken for cooking 200gm Dal (lentil soup): 2hrs 30min.
  • Method of cooking- One part of Dal mixed with water (twice the volume of Dal) and then placed in cooker.
  • Time taken for boiling two potatoes: 2hrs 30min.
  • Method of cooking- Potatoes are diced and cleaned with water and then placed in cooking pot without adding water. The wet surface of potato after water cleaning is sufficient for preparation of potato. Potato rather will not boil if water is added in the pot.
  • Taste of prepared food: Good

Approximate Cost Estimation (for prototype making)

<(Say, Rs.800 in Indian currency)>Rs. 790
1.Wooden for cooker box-Rs.70
2.GI sheet, 2ft x 2ft, for cover glass frame and reflector back: \\(sheet for reflector back support and for frame of cover glazing)Rs.60
3.Two Aluminium potsRs.80
4.Two pot standsRs.40
5.Aluminium foil, 4ft x 1.5ft @Rs.15 per ft.Rs.60
6.Mirror glass 1.5ft x 1ft @ Rs.40 per sq.ft-Rs60.
7.3mm thick plain window glass- 1.5ft x 1ft @Rs.20 /sq.ftRs.30
8.Dull black paint (DUCO paint):100 ml.approx @ Rs.215 per Lt-Rs.20
9.Paint for wooden box:Rs.30
9.Gasket material and adhesive-Rs.50
10.Hinge, stay links, handle, plastic seat, clips, screws etc.Rs.90
11.Overall labor costRs.200
TotalRs.790

Tools UsedEdit

Hand Saw, Hand Drill, Hand Shear, Rubber and Wooden Mallets, Pliers, Screwdriver Set, Wrench Set, Measuring Tape etc.

Manpower RequirementEdit

  • Carpenter: For making wooden cooker box -- one person, 2 hours.
  • Sheet metal worker for glass cover frame and reflector frame making -- one person, 3 hours.
  • Tin smith for soft soldering of joints at corners of glass cover frame and relector frame -- one person, 1 hour.
  • Fitter for final assembly work -- 1 person, 2 hours.

See alsoEdit

ContactEdit

See Sankha Subhra Datta.

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