International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 4 - Jun 2014
Experiment Study & Analysis of Solar Air
Heater With Offset Fin.
Nishant Sharma 1, Dr. Bhupendra Gupta2*
1
2*
Student, Master of Engineering, Heat Power, JEC, Jabalpur
Assistant Professor, Jabalpur Engineering College, Jabalpur, India
Abstract :- Many years since ,the enhancement
of the thermal heat transfer in different systems,
where the air is used , had drawn the attention
of many searchers .The air with its unfavorable
thermo physical properties presents a low heat
transfer coefficient . In spite of these mediocre
characteristics . the air is widely used as fluid of
heat transfer because other factors have been
taken into account . These factors have the
advantage of more large consideration than the
thermal performances , which and oneself
relegated to the background .When the air
systems are employed for the needs of heating or
drying, inexpensive materials are used and one
does not fear the inopportune leaks of circuit
like that encountered by using the water.
Key word; - Air inlet ,Air outlet , Aluminum
plate ,Temperature , offset fin
1.IntroductionVarious designs with different shapes and
dimensions of the air flow passage in plate type
of solar air collectors were tested .The effect of
the flow passage geometry on the heat
convective coefficients between the air stream
and the plate were particularly examined .A slit
and expanded aluminum foil matrices were used
to increase the thermal performance . Blackened
wire screen matrices was employed that permits
to improve the thermal performances . An
experimental investigation . was conducted on
two matrices constituted by randomly stacking
blackened wire screens . Wire matrices were
used in solar collectors to give higher thermal
performance in comparison to the flat plate
collector.
Other materials with different character and
forms were used ,various materials were tested .
the hollow spheres , the crushed glass . In these
ISSN: 2231-5381
cases ,the tests showed that the thermal
performances were improved in comparison of
those of flat plate collectors . The thermal
performances of solar air collectors had been
evaluated theoretically and experimentally ,
where the channel ducts of solar collector were
filled with semi-transparent material . From the
analysis of test results it was observed that the
collectors filled with semi-transparent balls and
tubes give high efficiencies than the flat plate
collector .These materials were used for the heat
collection and a storage of some part of heat in
depth. The tests of performance on the solar air
collectors which were lined with aluminum
chips .
2 . Experimental procedures
The solar air collector is constructed so that it
can be dismantled and certain elements
"transparent cover, the absorber-plate and the
back of duct# can be changed in order to vary
the collector configuration, This avoids making
several collectors with only a flate plate and four
rectangular offset plate fins absorbers are
designed. The exhaust fan is fixed at the outlet
collector, a dimmer switch permit to vary the
mass flow rate of the air, The nature of flow
regime was studied in wind tunnel and showed
the successive boundary layers that alternates
after each interruption.
The chest of solar air collector is wooden made
it presents a well insulation at the back and
lateral sides. This insulation is realized by a
polystyrene sheet of 3 cm thick sandwiched
between back and rear wooden plate, In the
present work only the absorber and the
transparent cover are changed they permit to
show their effect on the thermal performance.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 4 - Jun 2014
Two types of transparent covers are
experimented which are alveolar polycarbonate
sheets with double and triple walls, Four offset
plate fins absorbers are tested they present fins
with different length and interruption, The
number of tested collectors then attains height.
Figure .1. Control device
3. Results and discussionTable .1.Offset fin are 10mm, Airflow rate
are 1.5M3 / Minute
and Inlet Temperature are 30°C
Sr.No.
Time
Temperature in
Degree at output
1
10:00
36
2
11:00
38
3
12:00
41
4
13:00
50
5
14:00
48
6
15:00
44
7
16:00
41
Efficiency:
Temperature at inlet =30 °C
Temperature at outlet =50°C
ή= ( Temperature at outlet -Temperature at inlet)
/ Temperature at inlet
= (50-30)/30 =66.66%
Figure .2. Blower
Figure .3. Experimental setup
ISSN: 2231-5381
Figure .4. Offset fin are 10mm, Airflow rate
are 1.5M3 / Minute
and Inlet Temperature are 30°C
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International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 4 - Jun 2014
Table .2.Offset fin are 10mm, Airflow rate
are 3 M3 / Minute
and Inlet Temperature are 30°C
Table .3.Offset fin are 20mm, Airflow rate
are 1.5M3 / Minute
and Inlet Temperature are 30°C
Sr.No.
Time
Temperature in
Degree at output
Sr.No.
Time
Temperature in
Degree at output
1
10:00
38
1
10:00
40
2
11:00
39
2
11:00
42
3
12:00
43
3
12:00
45
4
13:00
52
4
13:00
55
5
14:00
49
5
14:00
52
6
15:00
46
6
15:00
49
7
16:00
42
7
16:00
42
Efficiency:
Efficiency:
Temperature at inlet =30 °C
Temperature at inlet =30 °C
Temperature at outlet =52°C
Temperature at outlet =55°C
ή= ( Temperature at outlet -Temperature at inlet)
/ Temperature at inlet
ή= ( Temperature at outlet -Temperature at inlet)
/ Temperature at inlet
= (52-30)/30 =73.33%
= (55-30)/30 =83.33%
Figure .5. Offset fin are 10mm, Airflow rate
are 3 M3 / Minute
and Inlet Temperature are 30°C
ISSN: 2231-5381
Figure .6. Offset fin are 20mm, Airflow rate
are 1.5M3 / Minute
and Inlet Temperature are 30°C
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International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 4 - Jun 2014
Table .4.Offset fin are 20mm, Airflow rate
are 3.0M3 / Minute
and Inlet Temperature are 30°C
Table .5.Offset fin are 30mm, Airflow rate
are 1.5M3 / Minute
and Inlet Temperature are 30°C
Sr.No.
Time
Temperature in
Degree at output
Sr.No.
Time
Temperature in
Degree at output
1
10:00
42
1
10:00
37
2
11:00
44
2
11:00
39
3
12:00
49
3
12:00
42
4
13:00
57
4
13:00
51
5
14:00
54
5
14:00
49
6
15:00
50
6
15:00
43
7
16:00
44
7
16:00
42
Efficiency:
Efficiency:
Temperature at inlet =30 °C
Temperature at inlet =30 °C
Temperature at outlet =57°C
Temperature at outlet =51°C
ή= ( Temperature at outlet -Temperature at
inlet) / Temperature at inlet
ή= ( Temperature at outlet -Temperature at inlet)
/ Temperature at inlet
= (57-30)/30 =90.00%
= (51-30)/30 =70.00%
Figure .7. Offset fin are 20mm, Airflow rate
are 3.0M3 / Minute
and Inlet Temperature are 30°C
ISSN: 2231-5381
Figure .8. Offset fin are 30mm, Airflow rate
are 1.5M3 / Minute
and Inlet Temperature are 30°C
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International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 4 - Jun 2014
Table .6.Offset fin are 30mm, Airflow rate
are 3.0M3 / Minute
and Inlet Temperature are 30°C
4.Conclusion:
Sr.No.
Time
Temperature in
Degree at output
1
10:00
38
2
11:00
40
3
12:00
45
4
13:00
53
5
14:00
50
6
15:00
46
The air stream reduces sensibly the temperature
of the absorber and in same time the heat losses
are reduced. With the offset fin collector the
double glazing gives lower thermal performance
than the triple glazing this is due to the heat
losses towards the surroundings. Then with the
triple glazing, the amount of intercepted
radiation transmitted to the absorber was
diminished but the global heat losses are further
reduced. The double glazing transmits more
radiation than the triple glazing cover but the
heat losses remains important. Using of Offset
fin are 20mm, Airflow rate are 3.0M3 / Minute
and Inlet Temperature are 30°C. Find out the
Efficiency are 90.00%
7
16:00
43
Reference
Efficiency:
Temperature at inlet =30 °C
Temperature at outlet =53°C
ή= ( Temperature at outlet -Temperature at inlet)
/ Temperature at inlet
= (53-30)/30 =76.66%
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Figure .9. Offset fin are 30mm, Airflow rate
are 3.0M3 / Minute
and Inlet Temperature are 30°C
ISSN: 2231-5381
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