This document presents an experimental study comparing the performance of two box-type solar cookers: one with a plain absorber plate and one with a finned absorber plate. The cookers were tested under conditions in Allahabad, India. It was found that the solar cooker with the finned base performed better, with a higher first figure of merit (F1) of 0.145 compared to 0.106 for the plain base cooker. Exergy efficiency was also higher for the finned base cooker. The study concludes that the finned base design improves the thermal performance of the box-type solar cooker.

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International Journal of Advanced Research in Engineering and Technology
(IJARET)
Volume 6, Issue 7, Jul 2015, pp. 01-06, Article ID: IJARET_06_07_001
Available online at
http://www.iaeme.com/IJARET/issues.asp?JTypeIJARET&VType=6&IType=7
ISSN Print: 0976-6480 and ISSN Online: 0976-6499
© IAEME Publication
___________________________________________________________________________
AN EXPERIMENTAL STUDY ON BOX-TYPE
SOLAR COOKER
Sonali Kesarwani, Ajeet Kumar Rai and Vivek Sachann
Department of Mechanical Engineering, SSET, SHIATS-Allahabad,
UP, India.
ABSTRACT
In this paper, box type solar cookers with plain and finned absorber plates
are experimentally investigated in Allahabad climate conditions. The Figure
of merits (F1 and F2) are calculated for both the systems. Performance is
evaluated on the basis of exergy analysis. It is found that solar cooker with
finned base is of A grade. The exergy efficiency of finned base box-type solar
cooker is higher than the unfinned base box type solar cooker.
Key words: Box type solar cookers, Exergy analysis and Solar intensity
Cite this Article: Kesarwani, S., Rai, A. K. and Sachann, V. An Experimental
Study on Box-Type Solar Cooker. International Journal of Advanced
Research in Engineering and Technology, 6(7), 2015, pp. 01-06.
http://www.iaeme.com/IJARET/issues.asp?JType=IJARET&VType=6&IType=7
_____________________________________________________________________
1. INTRODUCTION
Solar cooker is a convenient and accepted thermal device which is available
throughout the world. Its low-cost makes it very attractive commercially, especially
among the rural population in the developing countries. Mullick et al. [1] performed
no load and full load test on box type solar cooker and suggested two figures of merits
(F1 and F2) as a measure of its thermal performance. These parameters were also
accepted by Bureau of Indian Standard as benchmark indicator of itsthermal
performance. Funk and Larsor [2] and Funk [3] proposed new parameters for
performance estimation of solar cooker.
2. PERFORMANCE EVALUATION OF THE COOKER
2.1. Determination of F1
The value of F1 is determined by a stagnation test carried out under no-load condition
and is mathematically expressed as
=
ɳ
= (1)
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2. Sonali Kesarwani, Ajeet Kumar Rai and Vivek Sachann
http://www.iaeme.com/IJARET/index.asp 2 editor@iaeme.com
Where ɳ is the optical efficiency, defined as the fraction of the incident solar
radiation, which reaches the absorber and gets absorbed and the heat loss factor at
stagnation. The stagnation temperature of the absorbing plate( ), ambient
temperature ( ) and solar insolation ( ) are measured when a steady state is
reached.
Determination of F2
The F2 is obtained by heating the containers placed on the absorbing plate, i.e. under a
full-load condition and is mathematically expressed as:
=
!("# " $
%& '
( $/
( # $/
) (2)
Where * is the time when water temperature reached + in (o
C), * the time when
water temperature reached + (o
C), (* − * $ the time taken for heating water from
+ to + in seconds. (o
C) the average ambient temperature from the time period
t1 to t2, Gs (W/m2
) the average solar radiation from the time period t1 to t2 and (mCp)w
the product of the mass of water and specific heat (J/o
C).
3. ENERGY AND EXERGYANALYSIS
3.1. Energy analysis
For the steady-state flow process during finite time interval (Δt), the overall energy
balance equation for Solar box cooker can be written as
[Energy gained by water in the vessel] = [Energy supplied to water in the vessel] –
[Energy lost from water in the vessel] (3)
The energy gained by water in the vessel kept inside the cooker can be considered
as the output energy (Eo) of the system (in KJ) and is given as
-. = /01( + − + $ (4)
Where, m and Cp are the mass (kg) and specific heat capacity of the water (J/kgK)
respectively. Tw2and Tw1 are the instantaneous final and initial temperatures (K) of the
water during the full load test. In the expression above, the output energy depends
only on the difference in final and initial values of temperatures (Tw2 – Tw1) but in
actual practice, ambient temperature as well as the initial and the final temperature
values also play the role in deciding the efficiency of the system, and this type of
qualitative effect cannot be accommodated in the energy based approach.
The energy supplied to water in the vessel kept inside the cooker can be
considered as the input energy (Ei) of the system (in KJ) and is written as
-2 = 3∆* (5)
Where, Gs is instantaneous solar isolation (W/m2
) recorded over a time interval Δt,
during the test period; A is the gross area (m2
) of the glazing surface.
Thus, the instantaneous energy efficiency (ɳE) of the system can be defined as the
ratio of the energy gained by water to the ratio of the energy supplied to water and is
expressed below as
ɳ5 =
56
57
=
( # $
!∆"
(6)

3. Deformation and Detachment of Carbon Tetra Chloride Droplet in the Presence of Different
Concentration of Surfactant from Solid Substrate
http://www.iaeme.com/IJARET/index.asp 3 editor@iaeme.com
3.2. Exergy analysis
For the steady-state flow process during a finite time interval, the overall exergy
balance equation for solar box cooker can be written as [4, 5]
[OurtputExergy from SBC] = [Input Exergy to SBC] – [Exergy lost from SBC] (7)
The exergy of solar radiation, as the exergy input Exi to the solar cooker, can be
calculated using the available solar energy flux (Gs A Δt) and is expressible through
equation given below which has the widest acceptability [6, 7].
-82 = 91 +
<
= >
?
−
?
<
@ 3∆* (8)
Where, Ts is surface temperature of sun. The sun’s black body temperature of 5762 K
results in a solar spectrum concentrated primarily in the 0.3–3.0 µm wavelength band
[8]. Although the surface temperature of the sun (Ts) varies due to the spectral
distribution of sun light on the earth’s surface, the value of 5800 K has been
considered for performing calculations.
The exergy gained by water in the vessel kept inside the cooker due to rise in
temperature can be considered as the output exergy (Exo) of the system and expressed
as [9]
-8. = -. − /01 %& #
(9)
The instantaneous exergy efficiency (ɳA) of the system can be defined as the ratio
of the exergy gained by water to the ratio of the exergy supplied to water and is
depicted as
ɳA =
56 BC
D #
D
9 E
F
=
D
D
>
G GD
FD
@!∆"
(10)
3.3. Experimental setup
Two similar box type solar cookers have been fabricated to operate in the Saharan
Environment; they differ only by absorber plate shape [10, 11]. Figure 1 shows the
photographic view of box type solar cooker used in experiments. Box type solar
cookers were constructed using GI sheet and insulated by a layer of styro-foam
(Thermal conductivity = 0.033 W/m-K). For the first box solar cooker, the absorber
plate consists of GI sheet painted black of a surface area (0.5625 m2
i.e. 0.75 m × 0.75
m) and 0.0010058 m thickness. For the second one, the absorber plate is similar to
that of the first one but its upper surface is provided with fins made of GI painted
black. Fins are of rectangular cross section (0.75 m by 0.01 m) and have a length of
0.020 m.
4. RESULT AND DISCUSSIONS
Comparative study on two different type solar cookers, one with conventional and
another with fins integrated on the absorbing plate has been carried out based on the
exergy analysis. Figures 2, 3 and 4 shows observations taken on a particular day
during the experimentation.

4. Sonali Kesarwani, Ajeet Kumar Rai and Vivek Sachann
http://www.iaeme.com/IJARET/index.asp 4 editor@iaeme.com
Figure 2 shows the solar intensity with respect to the time of the day, Figure 3
shows the wind velocity with respect to the time of the day and Figure 4 shows the
variation of the temperature of different component of the cookers with respect to the
time of the day for one liter water in the cooker.
Figure 1 Photographic view of box-type solar cooker, without and with fins on the absorber
plate
Figure 2 Variation of solar intensity with time
From the Figure 4 it is found that the absorber plate temperature with fin is higher
than the absorber plate temperature without fins. According to Mullick et al., 1987 the
first figure of merit F1 varies between 0.12 and 0.16. A high value of F1 indicates
good optical efficiency and low heat loss factor. Their prototype will then be
classified as Grade A. For the experimental stagnation test, for finned and without
finned the figure of merit F1 is calculated as 0.10617; 0.145679 respectively by using
0
100
200
300
400
500
600
700
800
900
1000
SOLARINTENSITY(W/m2)
TIME (hr.)
Solar Intensity

5. Deformation and Detachment of Carbon Tetra Chloride Droplet in the Presence of Different
Concentration of Surfactant from Solid Substrate
http://www.iaeme.com/IJARET/index.asp 5 editor@iaeme.com
above equation with values of ambient temperature 41 °C; solar intensity 720 W/m2
and absorber plate temperature for finned and without finned solar cooker is 100 °C
and 84 °C respectively. Factor F1 and F2 are calculated by the equation 1 and 2
respectively.
Figure 3 Variation of wind velocity with time
Figure 4 Variation of temperature with time
Exergy input for finned and without finned base box type solar cooker is same
which is 1249821.248 and exergy out is 17014.35265 and 16533.3958 for finned and
without finned base box type solar cooker respectively.
5. CONCLUSION
On the basis of a comparative experimental study of two box-type solar cooker, which
have been tested under same conditions of Allahabad, the following conclusion have
been drawn:
0
0.5
1
1.5
2
2.5
WindVelocity(m/s)
Time (hr.)
Wind velocity
0
20
40
60
80
100
120
Temperature(oC)
Time(hr.)
Absorber plate temperature (with
fin)
Internal air temperature (with fin)

6. Sonali Kesarwani, Ajeet Kumar Rai and Vivek Sachann
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The first figures of merit (F1) is found as 0.145 for finned absorber plate box-type
solar cooker and 0.106 for without finned absorber plate box-type solar cooker.
According to BIS, finned absorber plate solar cooker falls in A Grade category.
The second figures of merit (F2) of finned solar cooker was 35.5% more than
without finned solar cooker.
The stagnation temperature for box-type solar cooker integrated with finned
absorber plate was about 19% higher than without fin absorber plate box-type solar
cooker.
REFERENCES
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type solar cooker. Solar Energy, 39, 1987, pp. 353–360.
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Solar Energy, 62(1), 1998, pp. 63–8.
[3] Funk, P. A. Evaluating the international standard procedure for testing solar
cookers and reporting performance. Solar Energy, 68(1), 2000, pp. 1–7.
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of box-type solar cooker with a finned absorber plate. Energy, 35, 2010, pp.
3799–3802.
[5] Kumar, N., Agravat, S., Chavda, T. and Mistry, H. N. Design and development of
efficient multipurpose domestic solar cookers/ dryers. Renewable Energy, 33,
2008, pp. 2207–2211.
[6] Ozturk, H. H. Comparision of energy and exergy efficiency for solar box and
parabolic cookers. J Energy Engg, 133(1), 2007, pp. 53–62.
[7] Petela, R. Exergy analysis of the solar cylindrical-parabolic cooker. Solar Energy,
79, 2005, pp. 221–233.
[8] Kreith, F. and Kreider, J. Principles of solar engineering. New York:
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[9] Kumar, N., Vishwanath, G. and Gupta, A. Anexergy based test protocol for
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