experimental investigation of forced circulation solar air heater along with integrated solar...

International Journal of Scientific Research and Engineering Studies (IJSRES)

Volume 1 Issue 4, October 2014

ISSN: 2349-8862

www.ijsres.com Page 50

Experimental Investigation Of Forced Circulation Solar Air Heater

Along With Integrated Solar Collector And Phase Change Material

(Paraffin Wax)

Mr. Kaushal Kishore

M.Tech student

Prof. (Dr.) S. C. Roy

HOD and Professor

Prof. J. N. Mahto

Prof. R. S. Prasad

Assistant Professor in Department of Mechanical

engineering, BIT Sindri

Abstract: Latent heat thermal energy storage is one of

the most efficient ways to store the thermal energy for

heating air by energy received from the sun. This project is

investigation and analysis of thermal energy storage

incorporating with phase change materials (PCM) and

integrated solar collector plate for use in solar air heater.

The integrated collector storage (ICS) concept is applicable

as direction in increasing the economic feasibility and more

attractive for space heating, cooling in domestic, agricultural

and industrial applications in buildings, solar applications,

off-peak energy storage, and heat exchanger improvements.

It focuses mostly on applications involving a reduction of

electric power consumption. A system of this combines

collection and storage of thermal energy in a single unit.

Compared with the other conventional domestic air heating

system, the integrated collector heating system has the more

advantage of simplicity, both in erection and in operation.

The thermal performance of this solar air heater with phase

change material and integrated collector plate are more than

conventional type because large surface area for heat

transfer is obtained. When the sun ray falls on the solar

collector plate, the panel or surface area is responsible for

the amount of heat storage. This heat energy is transferred

with the help of aluminium fins to the stored paraffin wax

which is used as a latent heat storage system. In this project

reflector plate with stand and paraffin wax is used. The

latent heat storage capacity of paraffin wax is more. So that

the amount of heat energy is increased with the help of this

reflector. Due to this more amount of heat energy the

difference of inlet air temperature and outlet air temperature

is more, so that high temperature of hot air is obtained and

efficiency of collector plate is increased. This improved

collector efficiency by reducing heat loss to the environment,

and help achieve an overall efficiency, which accosts of

pumping loss for moving air through the collector.

I. INTRODUCTION

Solar energy developed as a means of cheap energy for

Drying grains, fruits, vegetables, tea, and building heating,

space heating, drying for industrial & agriculture purposes.

The increasing need for renewable energy sources, specifically

solar energy, requires that research be conducted to improve

the efficiency of solar systems. Energy storage is not only

plays an important role in conservation the energy but also

improves the performance and reliability of wide range of

energy systems. Solar air heater is a simple device to heat air

by utilizing solar energy. Such heater is implemented in many

applications which require low temperature below 60°C. Solar

air heating (solar collector) is a renewable heating technology

and provides heat using solar energy. With fuel costs and other

factors, solar air heater is getting more attention. The

performance of SAH depends on a number of factors. There

are many advantages of solar air heater systems. Firstly, they

are simple to maintain and design. After the set-up cost, a

solar air heater system has no fuel expenditure. There is less

leakage and corrosion when compared to the systems that use

liquid. It is also an eco-friendly system which has zero

greenhouse gas emissions. It is really cost effective and simple

way to get 75% more power from any ordinary solar panel.

Modern air heater design, focused mainly on improves

conductive heat transfer and absorber plate temperature. Most

of the time a solar panel is working well below peak power,

and when the sun is lower in the sky, early morning and late

afternoon. The light levels are just not so enough. To boost the

sun light level so introduce a mirror or reflector plate to reflect

more Solar irradiation onto the solar collector plate. This is

probably one of the cheapest and easiest ways to boost the

power of a small solar collector plate. The greatest limitations

to increasing the use of conventional collectors are their

relatively low average efficiency and high investment cost.

For this reason, significant research on improving the

efficiency of collector plate has been carried out. It indicate

that the greatest theoretical improvements to the collector

efficiency can be achieved by utilizing internal fins in the

collector plates, reflective surface and phase change material

(paraffin wax). Phase change materials (PCM) are „„Latent

heat‟‟ storage materials. The thermal energy transfer occurs

when a material changes from solid to liquid, or liquid to

solid. Initially, these solid–liquid PCMs perform like

conventional storage materials; their temperature rises as they



ISSN: 2349-8862


absorb heat. Unlike conventional (sensible) storage materials,

PCM absorbs and release heat at a nearly constant

temperature. They store 5–14 times more heat per unit volume

than sensible storage materials such as water etc.

II. LITERATURE REVIEW

O. V. Ekechukwu. et.al [1]

they proposed designs and

performance technique of a flat plate solar energy air heating

collectors for low temperature. The design and construction of

solar air heating collectors at critical to overall performance

for either active or passive solar energy.

Gawlik Keith .et.al[2]

they developed an unglazed,

transparent-plate solar air heater for heating air directly. The

collector temperature was low, relative to systems that

recalculate the air. They used low cost materials like plastic to

reduce the cost of solar air heater.

Jaurker AR et.al[3]

They studied the heat transfer and

friction characteristics of collector plate in solar air heater. At

low flow rates the solar air heater with roughness elements

gives better performance. At high flow rate, the smooth duct

solar air heater had better efficiency.

Cemil Yamal. et.al[4]

They were investigate theoretically

the effect of different system operating conditions like types of

air heater, different design parameters and different weather

condition on a solar air heater. They used Runge-Kutta

method to solve the energy balance equations numerically

with double-pass solar air heater under the same operating

conditions.

E. Zambolin. .et.al [5]

were developed a glazed flat plate

collector usually present a metal absorber in a flat rectangular

housing. The glass covers on the upper surface and the

insulation on the other sides. The solar energy absorbed by the

plate is transferred to the liquid flowing within the collector

plate.

Ljiljana T. Kostic. et.al [6]

they proposed the influence of

reflectance from flat plate solar radiation concentrators made

of Al sheet. With the increase of solar radiation intensity

concentration factor and total daily thermal energy generated

by Thermal collector with concentrators increase.

III. EXPERIMENTAL PROCEDURE

Figure 1: experimental Set up

The solar collector along with its inlet and outlet ducts

was installed at an angle of 20.58º south to the horizontal. A

centrifugal air blower was attached to the inlet and placed with

a voltage regulator so that the inlet air flow rate can be varied

precisely across a wide scale. However, in this test

measurement range was limited to 1.5-4 m/s.

A flow straightener (Triangular) was used at the inlet and

outlet, to guarantee uniform flow into the solar collector. A

pyranometer measuring short wave radiation was connected at

the same slope to as the collector to read solar radiation flux

(W/m2) on the inclined surface.

A hot wire anemometer was installed, and its reading was

taken at several locations across the perpendicular plane to the

flow direction so that an average velocity is measured. This

measurement is used to determine the air flow rate across the

unit.

Reading were obtained for two inlet air temperature

values and two outlet air temperature values, in addition to six

reading of the temperature of the absorber plate at different

location along the length and across the width. These ten

reading were taken by the use of J-Type thermocouple. The

thermocouples were connected to 6-channel thermocouple

amplifier. In addition, another J-type thermocouple was

connected to measure the ambient air temperature. The

pyranometer output reading was converted into a heat flux

using the calibration relation (1mV=129.31W/ as per

specification).

Once the unit was connected, it was left to run for about 2

days before the measurements were taken, in order to

overcome the initial transient effects and to confirm reliable

operation of the unit. Then, the experiment was run at steady

state for a period of 9 days at PG Hostel B.I.T, Sindri.

IV. OBSERVATION AND CALCULATION

The reading was taken for first three days in one mass

flow rate (0.015 Kg/s) and for next three days in second mass

flow rate (0.020 Kg/s) and same for next three days in third

mass flow rate (0.025 Kg/s).Observation was taken from 6:00

am to 5:00 am next day with one hour interval, for 24 hour

(Day and night).

The obtain data with corresponding date are given in

below mentioned tables Time

(hr)

Tamb

( )

Inlet

Temp.

( )

Outlet

Temp.

( )

Absorber plate temperature

( )

Solar

Irradiation

(W/m2)

Ti1 Ti2 To1 To2 TP1 TP2 TP3 TP4 TP5 TP6

06 22 23 23 30 30 27 28 33 34 36 36 0

07 28 30 30 38 39 34 36 35 38 42 44 437.551

08 31 32 32 43 44 36 38 40 44 47 49 621.1712

09 37 39 38 49 50 42 44 46 48 52 55 723.3261

10 40 42 43 53 53 47 49 50 52 55 59 772.4639

11 42 45 44 55 56 48 50 52 54 58 61 839.7051

12 45 44 43 57 58 47 50 54 58 60 63 895.3084

13 46 46 45 60 60 49 52 56 60 64 66 969.0151

14 45 44 45 58 58 49 51 55 59 64 64 906.9463

15 44 46 45 52 52 49 50 55 58 62 58 808.6707

16 40 45 45 48 48 49 54 56 58 60 54 716.8606

17 39 43 42 46 46 46 49 52 56 60 52 622.4643

18 38 40 39 45 45 43 46 50 54 57 51 453.0682



ISSN: 2349-8862


19 35 36 37 44 44 41 44 47 50 52 50 0

20 32 32 34 43 43 38 40 42 46 50 49 0

21 29 30 32 43 43 36 38 41 44 48 49 0

22 28 30 30 42 42 34 37 40 42 45 48 0

23 28 28 30 42 42 34 36 39 39 44 48 0

00 27 27 28 42 42 32 34 37 40 44 48 0

01 26 27 27 41 41 31 33 35 38 40 47 0

02 25 26 27 36 36 31 31 35 36 38 42 0

03 23 25 24 32 33 28 30 30 34 36 38 0

04 23 24 22 29 29 26 29 31 33 36 35 0

05 22 23 22 27 27 26 29 33 36 37 33 0

Observation Table1: First Day Mass flow rate (ṁ1) =0.015

kg/s Time

(hr)

Tamb

( )

Inlet

Temp.

( )

Outle

Temp.

( )


( )

Solar

Irradiation

(W/m2)


06 25 25 26 31 31 30 33 34 37 39 37 0

07 29 29 29 40 41 33 35 36 40 44 46 456.481

08 34 35 37 48 48 41 45 52 56 50 54 647.0332

09 39 40 41 54 54 45 45 46 50 55 60 652.2056

10 41 42 43 54 55 47 49 52 55 59 60 794.4466

11 42 43 43 56 56 47 50 53 56 60 62 944.4462

12 45 46 47 58 58 51 52 54 56 60 64 824.317

13 46 47 46 60 61 50 54 57 60 63 66 944.4462

14 47 48 47 60 60 51 55 58 62 63 66 837.1189

15 47 46 47 56 56 51 55 59 61 63 62 787.9811

16 44 45 46 52 52 50 52 57 60 62 58 648.3262

17 41 42 44 48 48 48 50 54 57 60 54 468.5854

18 36 37 38 46 46 42 44 47 52 54 52 325.0513

19 33 35 36 44 44 40 42 46 50 52 50 0

20 31 33 34 43 43 38 41 45 46 50 49 0

21 30 32 33 43 43 37 40 44 45 50 49 0

22 29 31 31 42 42 35 38 43 45 47 48 0

23 29 30 31 41 42 35 40 41 42 43 47 0

00 28 30 29 41 43 33 36 40 42 44 47 0

01 26 28 29 39 39 33 35 38 41 43 45 0

02 25 27 28 34 34 32 35 37 39 40 40 0

03 25 27 27 32 32 31 35 36 38 39 38 0

04 24 24 23 29 29 27 30 34 37 37 35 0

05 24 23 24 28 28 28 30 34 34 36 34 0

Observation Table2: Second Day Mass flow rate (ṁ1) =0.015

kg/s Time

(hr)

Tamb

( )

Inlet

Temp.

( )

Outlet

Temp.

( )


( )

Solar

Irradiation

(W/m2)


06 23 24 25 29 30 35 35 35 35 37 38 0

07 25 24 26 30 30 33 34 35 35 35 36 511.2577

08 29 30 28 42 42 35 33 34 35 40 40 636.6884

09 32 31 33 46 46 37 38 40 44 43 44 773.757

10 36 36 37 51 53 41 42 46 50 52 57 838.412

11 40 42 42 56 56 46 43 54 56 58 62 928.929

12 44 46 44 59 59 51 54 57 60 63 65 869.4464

13 45 46 45 59 60 56 60 63 64 65 65 878.4981

14 45 44 43 53 53 54 56 58 60 62 59 852.6361

15 43 42 43 48 48 52 55 57 59 61 54 710.3951

16 42 42 41 47 48 49 53 55 58 60 53 569.4472

17 39 40 41 46 46 45 47 51 54 56 52 464.7061

18 36 37 38 46 46 42 44 48 50 53 52 441.4303

19 33 33 35 45 45 39 40 44 48 51 52 0

20 30 30 31 45 45 36 38 41 44 46 48 0

21 29 30 29 43 43 34 36 38 41 42 44 0

22 27 28 28 41 42 34 35 37 38 41 47 0

23 27 28 27 38 37 33 35 37 37 40 44 0

00 25 25 26 34 34 32 34 35 36 38 40 0

01 25 25 25 31 31 32 33 34 35 37 37 0

02 24 24 24 30 30 31 32 33 34 35 37 0

03 24 24 23 3 30 31 32 33 34 34 36 0

04 23 23 24 29 29 30 31 32 33 34 36 0

05 22 22 23 28 28 27 30 32 33 34 34 0

Observation Table3: Third Day Mass flow rate (ṁ1) =0.015

kg/s Time

(hr)

Tamb

( )

Inlet

Temp.

( )

Outlet

Temp.

( )


( )

Solar

Irradiation

(W/m2)


06 22 23 22 30 30 26 28 30 30 31 35 0

07 28 28 29 39 39 33 34 36 38 40 44 468.5854

08 32 32 33 45 45 37 38 40 41 44 50 609.5333

09 38 38 39 51 51 43 43 47 49 52 56 678.0676

10 40 40 41 52 52 45 47 49 50 54 57 793.1535

11 43 43 44 55 55 48 50 53 57 58 60 825.481

12 45 45 46 55 56 50 54 56 60 62 61 904.3601

13 46 46 46 56 56 50 53 58 61 62 61 984.5323

14 46 45 45 55 55 49 51 55 58 61 60 939.2738

15 45 46 47 52 52 51 56 60 60 63 57 894.0153

16 44 45 46 49 49 50 52 56 58 60 54 696.171

17 42 42 42 45 45 46 50 53 57 61 50 667.7228

18 39 42 41 43 43 45 47 50 55 58 48 556.5162

19 38 40 39 42 42 43 40 46 54 57 47 0

20 36 37 38 42 42 42 44 48 50 55 47 0

21 34 34 35 41 41 39 41 45 48 48 46 0

22 32 32 33 41 45 37 38 40 44 48 50 0

23 31 32 32 40 40 36 38 40 42 46 45 0

00 29 30 30 40 40 34 35 38 42 45 45 0

01 29 30 30 39 39 34 32 34 37 40 44 0

02 28 29 29 35 35 33 33 36 39 40 40 0

03 24 24 25 31 32 29 30 32 34 37 37 0

04 22 25 25 30 30 29 30 30 34 35 35 0

05 22 24 23 29 29 27 28 30 33 35 34 0

Observation Table4: Fourth Day Mass flow rate (ṁ2) =020

kg/s Time

(hr)

Tamb

( )

Inlet

Temp.

( )

Outlet

Temp. ( )


( )

Solar

Irradiation

(W/m2)


06 23 25 24 32 32 28 29 31 31 32 28 0

07 29 29 29 37 37 33 31 34 36 38 33 517.7232

08 31 33 32 44 44 36 36 37 39 44 36 675.4814

09 36 38 37 50 50 41 41 44 47 50 41 723.3261

10 37 41 40 54 54 44 45 47 53 56 44 802.2052

11 39 43 42 56 56 46 49 52 56 58 46 869.4464

12 42 44 43 52 52 47 50 55 57 58 47 892.7222

13 43 45 46 51 51 50 53 56 58 61 50 930.2221

14 43 46 45 48 48 49 52 55 58 60 49 903.067

15 43 43 43 48 48 47 53 56 59 61 47 842.2913

16 39 39 39 44 44 43 52 55 58 60 43 772.4639

17 38 38 38 43 43 42 50 54 56 59 42 658.6711

18 37 37 37 42 42 41 48 50 52 55 41 495.7405

19 36 37 36 41 41 40 44 46 50 52 40 0

20 35 35 36 40 41 40 43 45 46 50 40 0

21 35 35 33 40 40 37 40 42 44 48 37 0

22 32 33 34 40 40 38 40 42 45 47 38 0

23 31 33 33 39 39 37 39 40 44 47 37 0

00 29 30 31 39 39 35 36 39 42 44 35 0

01 28 29 30 36 36 34 36 38 40 41 34 0

02 26 28 28 32 32 32 34 37 39 40 32 0



ISSN: 2349-8862


03 25 26 27 31 31 31 31 34 35 37 31 0

04 25 26 25 30 30 29 30 33 35 37 29 0

05 25 26 24 29 29 28 29 31 34 36 28 0

Observation Table5: Fifth Day Mass flow rate (ṁ2) =0.020

kg/s Time

(hr)

Tamb

( )

Inlet

Temp.

( )

Outlet

Temp. ( )


( )

Solar

Irradiation

(W/m2)


06 25 27 26 34 34 30 32 34 37 37 39 0

07 30 30 29 39 39 33 34 36 38 40 44 517.7232

08 35 37 38 47 47 42 43 43 44 46 52 669.0159

09 38 40 41 50 50 45 45 47 49 52 55 755.6536

10 39 42 44 52 52 48 51 52 55 58 57 833.2396

11 39 45 46 56 56 50 52 54 58 60 61 921.1704

12 40 45 44 55 55 48 50 55 58 60 60 914.7049

13 40 45 46 53 53 50 54 56 60 62 58 958.6703

14 41 42 42 48 48 46 55 57 61 63 53 909.5325

15 41 41 41 46 46 45 54 56 58 60 51 855.2223

16 38 38 38 43 43 42 55 57 58 60 48 703.9296

17 35 36 36 41 41 40 50 52 55 58 46 582.3782

18 34 35 35 41 41 39 46 48 49 52 46 503.4991

19 34 34 34 41 41 38 40 42 44 47 46 0

20 33 32 34 40 40 38 39 40 40 42 45 0

21 30 32 32 40 40 36 39 38 40 42 45 0

22 29 30 30 39 39 34 37 37 39 41 44 0

23 28 30 29 39 39 33 35 36 36 39 44 0

00 28 29 30 38 38 34 34 36 38 40 43 0

01 26 28 28 34 34 32 33 35 37 40 39 0

02 25 28 27 31 31 31 33 36 40 41 36 0

03 25 26 26 30 30 30 30 33 34 35 35 0

04 24 26 26 29 30 30 30 31 33 36 35 0

05 24 24 24 29 29 28 30 30 33 35 34 0

Observation Table6: Sixth Day Mass flow rate (ṁ2) =0.020

kg/s Time

(hr)

Tamb

( )

Inlet

Temp.

( )

Outlet

Temp. ( )


( )

Solar

Irradiation

(W/m2)


06 22 23 22 27 27 26 26 28 30 31 31 0

07 26 27 28 35 36 32 34 36 38 39 40 489.275

08 31 31 31 40 41 35 36 37 39 43 45 659.9642

09 35 36 35 44 45 39 41 43 44 46 49 806.0845

10 40 41 42 49 50 46 45 45 48 50 54 820.3086

11 43 43 44 53 52 48 49 51 56 56 56 927.6359

12 44 44 45 54 55 49 50 53 55 57 59 931.5152

13 45 45 46 55 55 50 52 55 58 60 59 939.2738

14 45 45 45 54 54 49 50 54 57 58 58 897.8946

15 45 45 45 52 52 49 50 52 55 58 56 800.9121

16 43 44 44 48 48 48 49 53 55 57 52 564.2748

17 41 41 41 45 45 45 46 49 51 55 49 504.7922

18 39 39 39 43 43 43 48 48 50 52 47 450.482

19 37 38 38 41 41 42 46 47 49 51 45 0

20 37 38 38 40 40 42 43 45 48 50 44 0

21 36 37 37 40 40 41 41 43 44 48 44 0

22 36 37 37 39 39 41 39 40 43 47 43 0

23 34 35 35 39 39 39 36 39 41 42 43 0

00 32 33 33 38 38 37 36 37 40 41 42 0

01 29 30 30 35 35 34 35 36 38 40 39 0

02 28 29 29 33 33 33 33 34 36 38 37 0

03 26 27 27 31 31 31 32 34 35 36 35 0

04 25 25 25 30 30 29 30 32 33 34 34 0

05 24 24 25 29 29 29 30 31 33 34 33 0

Observation Table7: Seventh Day Mass flow rate (ṁ3) =0.025

kg/s

Time

(hr)

Tamb

( )

Inlet

Temp.

( )

Outlet

Temp. ( )


( )

Solar

Irradiation

(W/m2)


06 23 23 23 26 27 27 27 28 29 30 27 0

07 27 28 29 34 34 33 36 36 38 39 33 463.413

08 30 30 31 37 37 35 37 39 40 43 35 610.8264

09 35 36 37 44 46 41 42 44 46 48 41 679.3607

10 41 41 41 48 48 45 49 50 52 54 45 764.7053

11 42 42 42 50 50 46 50 53 56 58 46 839.7051

12 43 43 43 52 52 47 52 54 58 59 47 894.0153

13 44 44 44 53 53 48 53 54 59 60 48 904.3601

14 44 45 45 51 51 49 51 53 56 58 49 840.9982

15 45 45 45 48 48 49 50 52 55 57 49 798.3259

16 41 41 41 45 46 45 48 50 52 55 45 706.5158

17 37 37 37 41 41 41 47 49 51 54 41 640.5677

18 36 36 36 40 40 40 46 47 49 52 40 546.1714

19 34 34 34 40 40 38 43 45 47 50 38 0

20 34 34 34 39 39 38 39 41 45 46 38 0

21 33 33 33 39 39 37 37 38 40 42 37 0

22 33 33 33 38 38 37 34 36 38 40 37 0

23 31 31 31 38 38 35 33 35 37 39 35 0

00 30 31 31 36 36 35 34 37 37 39 35 0

01 28 28 29 33 33 33 33 35 36 38 33 0

02 25 26 26 30 30 30 30 33 36 37 30 0

03 24 24 24 30 31 28 29 30 32 34 28 0

04 24 24 23 27 28 27 28 29 31 33 27 0

05 22 23 22 26 27 26 27 27 29 30 26 0

Observation Table8: Eighth Day Mass flow rate (ṁ3) =0.025

kg/s Time

(hr)

Tamb

( )

Inlet

Temp.

( )

Outlet

Temp. ( )


( )

Solar

Irradiation

(W/m2)


06 22 23 22 25 25 26 26 27 28 30 29 0

07 28 29 30 35 35 34 32 36 38 38 39 528.068

08 33 34 36 41 41 40 41 41 42 46 45 566.861

09 37 38 39 45 45 43 42 44 47 50 49 662.5504

10 40 40 40 48 48 44 45 47 50 53 52 809.9638

11 41 42 42 50 53 46 51 52 55 57 57 921.1704

12 42 43 43 53 53 47 52 54 58 60 57 918.5842

13 42 44 44 53 53 48 54 57 60 62 57 956.0841

14 43 43 43 50 50 47 53 54 56 59 54 895.3084

15 43 43 43 46 46 47 52 55 58 61 50 781.5156

16 40 40 40 43 43 44 51 56 58 60 47 581.0851

17 39 40 39 41 41 43 45 49 50 53 45 528.068

18 35 35 36 39 39 40 42 46 48 50 43 463.413

19 32 32 33 39 39 37 41 44 45 46 43 0

20 31 32 33 38 38 37 38 40 42 44 42 0

21 31 32 33 38 38 37 38 39 40 42 42 0

22 30 30 31 37 37 35 37 39 40 43 41 0

23 28 29 30 36 36 34 34 36 38 40 40 0

00 27 28 28 33 33 32 33 36 38 39 37 0

01 26 27 28 31 31 32 33 34 35 37 35 0

02 25 25 27 30 30 31 33 33 36 36 34 0

03 24 25 26 29 30 30 30 31 32 34 34 0

04 23 24 24 28 28 28 30 31 33 32 32 0



ISSN: 2349-8862

www.ijsres.com 4

05 23 23 23 26 26 27 28 30 32 31 30 0

Observation Table9: Ninth Day Mass flow rate (ṁ3) =0.025

kg/s

Sample Calculation: for second Reading of third day

Data from: Reading

= 25 ºC I = 5.95 mv = (3.95× 129.31)

= 511.25 W/m2

= 25 ºC V= 1.5 m/s

= 30 ºC = 1.175 Kg/m3

= 27.5ºC

Data from: (Data Hand book by Domkundwar &

Domkundwar)

= 1.205 Kg/

= 1.165 Kg/

= 1.167 Kg/

= 1.120 Kg/

= 1.6120× /s

= 0.02647 W/m K

Pr = 0.699

Cp = 1005 J/Kg K

Geometrical Data:

Cross-section Area of duct ( ) = (w × d) = (0.30×0.03) =

0.009

Perimeter of duct = 2(0.30+0.03) = 0.66 m

Panel Area (AP ) = ( l × w ) = (2× 0.30) = 0.6 m2

Equivalent Diameter ( ) = = 0.05454 m

Hydraulic Radius ( ) = = 0.013636 m

ASSUMPTION:

Mass flow rate (ṁ1) of air is taken on average temperature

of flowing air stream at 38.94 ºC.





CALCULATION:

1. Mass flow rate (ṁ1) = × V × AC) = 0.015 Kg/s



4. Reynolds number ( = = = =

5075.434

5. Friction Factor ( ) =

= = 0.038387

6. Nusselt Number (Nu) =

=

=16.81001

7. Convective Heat Transfer Coefficient (h) =

= =

8.2366 W/m2k

8. Efficiency (η) =

= = 24.572%

Time(hrs.)

DAY 1

Re f Nu H

06 5276.239 0.03793 17.40431 8.294172

07 4950.145 0.038686 16.43478 8.068529

08 4872.321 0.038877 16.19992 8.012027

09 4713.989 0.039281 15.71759 7.891648

10 4615.267 0.039543 15.41371 7.814381

11 4567.994 0.039698 15.23626 7.768983

12 4525.847 0.039787 15.13627 7.742631

13 4520.616 0.039712 15.33441 7.794074

14 4525.847 0.039787 15.13627 7.742631

15 4539.636 0.039612 15.33441 7.794074

16 4615.267 0.039543 15.41371 7.814381

17 4628.191 0.039508 15.45363 7.824499

18 4688.786 0.039421 15.61401 7.851713

19 4817.027 0.039016 16.03215 7.971321

20 4879.294 0.038869 16.22141 8.017112

21 4907.392 0.038791 16.30591 8.037553

22 4950.145 0.038686 16.43478 8.068529

23 4950.145 0.038686 16.43478 8.068529

00 4971.804 0.038634 16.49992 8.084162

01 4993.652 0.038581 16.56548 8.09893

02 5075.434 0.038387 16.81001 8.158435

03 5236.559 0.038018 17.28755 8.267847

04 5236.559 0.038018 17.28755 8.267847

05 5276.239 0.03793 17.40431 8.294172

Table 1: Calculated values of Reynolds number, friction

factor, Nusselt number and Convective heat transfer

coefficient for mass flow rate ṁ1

Time(hrs.)

DAY 2

Re f Nu H

06 5075.434 0.038387 16.81001 8.158435

07 4907.392 0.038791 16.30591 8.037553

08 4768.388 0.039141 15.88399 7.933838

09 4628.191 0.039508 15.45363 7.824499

10 4596.017 0.039595 15035416 7.79912

11 4567.994 0.039698 15.23626 7.768983

12 4525.847 0.039787 15.13627 7.742631

13 4520.616 0.039712 15.33441 7.794074

14 4487.864 0.039893 15.01778 7.711343

15 4487.864 0.039893 15.01778 7.711343

16 4539.636 0.039612 15.33441 7.794074

17 4596.017 0.039595 15.35416 7.79912

18 4775.276 0.039122 15.9051 7.93916

19

4830.893

0.038981 16.07 428 7.981808

20 4872.321 0.038877 16.19992 8.012027

21 4886.288 0.0338843 16.24215 8.022207

22 4907.392 0.038791 16.30591 8.037553

23 4907.392 0.038791 16.30591 8.037553

00 4950.145 0.038686 16.43478 8.068529

01 4993.652 0.038581 16.56548 8.09893

02 5075.434 0.038387 16.81001 8.158435



ISSN: 2349-8862


03 5075.434 0.038387 16.81001 8.158435

04 5228.695 0.038036 17.26436 8.262616

05 5228.695 0.038036 17.26436 8.262616




Time(hrs.)

DAY 3

Re F Nu H

06 5276.239 0.03793 17.40431 8.294172

07 5075.434 0.038387 16.81001 8.158435

08 4907.392 0.038791 16.30591 8.037553

09 4879.294 0.038869 16.22141 8.017112

10 4775.276 0.039122 15.9051 7.93916

11 4615.267 0.039543 15.41371 7.814381

12 4539.636 0.039612 15.33441 7.794074

13 4525.847 0.039787 15.13627 7.742631

14 4525.847 0.039787 15.13627 7.742631

15 4560.616 0.039368 15.61514 7.865618

16 4567.994 0.039698 15.23626 7.768983

17 4628.191 0.039508 15.45363 7.824499

18 4775.276 0.039122 15.9051 7.93916

19 4830.893 0.038981 16.07 428 7.981808

20 4886.288 0.0338843 16.24215 8.022207

21 4907.392 0.038791 16.30591 8.037553

22 4971.804 0.038634 16.49992 8.084162

23 4971.804 0.038634 16.49992 8.084162

00 5075.434 0.038387 16.81001 8.158435

01 5075.434 0.038387 16.81001 8.158435

02 5228.695 0.038036 17.26436 8.262616

03 5228.695 0.038036 17.26436 8.262616

04 5236.559 0.038018 17.28755 8.267847

05 5276.239 0.03793 17.40431 8.294172




Time(hrs.)

DAY 4

Re f Nu H

06 6971.593 0.034874 22.13868 10.59543

07 6667.971 0.035337 21.32259 10.4189

08 6477.911 0.035643 20.80543 10.30353

09 6258.545 0.035812 20.20214 10.16302

10 6303.296 0.036104 20.05566 10.12849

11 6102.569 0.036286 19.76877 10.06082

12 6060.108 0.036363 19.65014 10.03242

13 6042.987 0.036394 19.60223 10.02071

14 6042.987 0.036394 19.60223 10.02071

15 6060.108 0.036363 19.65014 10.03242

16 6170.921 0.036165 19.95914 10.10574

17 6205 .674 0.036135 20.32579 10.19215

18 6348.693 0.035858 20.45092 10.22161

19 6258.545 0.035812 20.20214 10.16302

20 6441.191 0.035703 20.70494 10.28119

21 6487.155 0.035628 20.83071 10.30975

22 6477.911 0.035643 20.80543 10.30353

23 6581.081 0.035575 21.08678 10.36632

00 6619.417 0.035475 21.28678 10.36632

01 6619.417 0.035475 21.28678 10.36632

02 6667.971 0.035337 21.32259 10.4189

03 6888.826 0.034997 21.91741 10.43668

04 6971.593 0.034874 22.13868 10.59543

05 6971.593 0.034874 22.13868 10.59543




Time(hrs.)

DAY 5

Re f Nu H

06 6919.632 0.034951 21.99986 10.56631

07 6619.417 0.035475 21.28678 10.36632

08 6581.081 0.035575 21.08678 10.36632

09 6441.191 0.035703 20.70494 10.28119

10 6413.357 0.035751 20.62863 10.26344

11 6348.693 0.035858 20.45092 10.22161

12 6205 .674 0.036135 20.32579 10.19215

13 6102.569 0.036286 19.76877 10.06082

14 6102.569 0.036286 19.76877 10.06082

15 6102.569 0.036286 19.76877 10.06082

16 6348.693 0.035858 20.45092 10.22161

17 6258.545 0.035812 20.20214 10.16302

18 6413.357 0.035751 20.62863 10.26344

19 6441.191 0.035703 20.70494 10.28119

20 6450.331 0.035688 20.72997 10.28688

21 6450.331 0.035688 20.72997 10.28688

22 6477.911 0.03 5643 20.80543 10.30353

23 6581.081 0.035575 21.08678 10.36632

00 6619.417 0.035475 21.28678 10.36632

01 6667.971 0.035337 21.32259 10.4189

02 6858.292 0.035043 21.83554 10.53263

03 6899.064 0.034982 21.94482 10.55637

04 6899.064 0.034982 21.94482 10.55637

05 6899.064 0.034982 21.94482 10.55637




Time(hrs.)

DAY 6

Re f Nu H

06 6899.064 0.034982 21.94482 10.55637

07 6629.071 0.035399 21.11715 10.39539

08 6450.331 0.035688 20.72997 10.28688

09 6258.545 0.035812 20.20214 10.16302

10 6348.693 0.035858 20.45092 10.22161

11 6348.693 0.035858 20.45092 10.22161

12 6303.296 0.036104 20.05566 10.12849

13 6303.296 0.036104 20.05566 10.12849

14 6231.997 0.036058 20.12864 10.14571

15 6231.997 0.036058 20.12864 10.14571

16 6258.545 0.035812 20.20214 10.16302

17 6450.331 0.035688 20.72997 10.28688

18 6487.155 0.035628 20.83071 10.30975

19 6487.155 0.035628 20.83071 10.30975

20 6496.427 0.035612 20.85604 10.31483

21 6629.071

0.035399

21.11715 10.39539

22 6619.417 0.035475 21.28678 10.36632

23 6667.971 0.035337 21.32259 10.41891

00 6667.971 0.035337 21.32259 10.41891

01

6858.292

0.035043

21.83554 10.53263



ISSN: 2349-8862


02 6899.064 0.034982 21.94482 10.55637

03 6899.064 0.034982 21.94482 10.55637

04 6888.826 0.034997 21.91741 10.43668

05 6888.826 0.034997 21.91741 10.43668

Table 6 : Calculated values of Reynolds number, friction



Time(hrs.)

DAY 7

Re f Nu H

06 8807.079 0.032587 26.85125 12.78708

07 8446.482 0.032979 25.95171 12.60376

08 8238.279 0.033217 25.42698 12.49158

09 8040.094 0.033351 24.92367 12.38415

10 7789.997 0.033759 24.28294 12.23965

11 7681.388 0.033897 24.00269 12.17651

12 7617.664 0.033979 23.83767 12.13934

13 7585.881 0.034021 23.75521 12.12053

14 7585.881 0.034021 23.75521 12.12053

15 7585.881 0.034021 23.75521 12.12053

16 7681.388 0.033897 24.00269 12.17651

17 7702.867 0.033869 24.05821 12.18901

18 7856.649 0.033675 24.45432 12.27828

19 8085.863 0.033396 25.04024 12.40947

20 8085.863 0.033396 25.04024 12.40947

21 8108.944 0.033369 25.09895 12.42154

22 8108.944 0.033369 25.09895 12.42154

23 8132.156 0.033341 25.15794 12.43505

00 8226.351 0.033231 25.39681 12.48513

01 8347.209 0.033091 25.70202 12.55035

02 8396.552 0.033035 25.82624 12.57692

03 8446.482 0.032979 25.95171 12.60376

04 8649.542 0.032755 26.45967 12.70831

05 8688.394 0.032714 26.55644 12.72776




Time(hrs.)

DAY 8

Re f Nu H

06 8793.732 0.032601 26.18161 12.78042

07 8459.057 0.032965 25.38328 12.61051

08 8250.242 0.033203 25.45724 12.49804

09 8040.094 0.033351 24.92367 12.38415

10 7702.867 0.033869 24.05821 12.18901

11 7746.187 0.033814 24.17004 12.21421

12 7681.388 0.033897 24.00269 12.17651

13 7617.664 0.033979 23.83767 12.13934

14 7617.664 0.033979 23.83767 12.13934

15 7585.881 0.034021 23.75521 12.12053

16 7702.867 0.033869 24.05821 12.18901

17 8085.863 0.033396 25.04024 12.40947

18 8108.944 0.033369 25.09895 12.42154

19 8132.156 0.033341 25.15794 12.43505

20 8132.156 0.033341 25.15794 12.43505

21 8178.983 0.033286 25.27679 12.46089

22 8178.983 0.033286 25.27679 12.46089

23 8238.279 0.033217 25.42698 12.49158

00 8250.242 0.033203 25.45724 12.49804

01 8396.552 0.033035 25.82624 12.57692

02 8649.542 0.032755 26.45967 12.70831

03 8688.394 0.032714 26.55644 12.72776

04 8688.394 0.032714 26.55644 12.72776

05 8807.079 0.032587 26.85125 12.78708




Time(hrs.)

DAY 9

Re f Nu H

06 8807.079 0.032587 26.85125 12.78708

07 8396.552 0.033035 25.82624 12.57692

08 8178.983 0.033286 25.27679 12.46089

09 8085.863 0.033396 25.04024 12.40947

10 7789.997 0.033759 24.28294 12.23965

11 7702.867 0.033869 24.05821 12.18901

12 7746.187 0.033814 24.17004 12.21421

13 7746.187 0.033814 24.17004 12.21421

14 7681.388 0.033897 24.00269 12.17651

15 7681.388 0.033897 24.00269 12.17651

16 7789.997 0.033759 24.28294 12.23965

17 7856.649 0.033675 24.45432 12.27828

18 8040.094 0.033351 24.92367 12.38415

19 8226.351 0.033231 25.39681 12.48513

20 8238.279 0.033217 25.42698 12.49158

21 8238.279 0.033217 25.42698 12.49158

22 8250.242 0.033203 25.45724 12.49804

23 8396.552 0.033035 25.82624 12.57692

00 8459.057 0.032965 25.38328 12.61051

01 8446.482 0.032979 25.95171 12.60376

02 8649.542 0.032755 26.45967 12.70831



ISSN: 2349-8862


03 8688.394 0.032714 26.55644 12.72776

04 8793.732 0.032601 26.18161 12.78042

05 8793.732 0.032601 26.18161 12.78042



coefficient for mass flow rate ṁ3 Tim

e

(hrs

.)

DAY

1

DAY

2

DAY

3

DAY

4

DAY

5

DAY

6

DAY

7

DAY

8

DAY

9

ɳ

(%)

ɳ (%) ɳ

(%)

ɳ

(%)

ɳ

(%)

ɳ

(%)

ɳ

(%)

ɳ (%) ɳ

(%)

07 44.50 46.78 24.57 64.34 50.14 55.00 53.4

9

40.66 31.71

08 40.44 45.62 33.54 63.20 48.35 47.56 55.5

2

41.13 42.47

09 39.07 49.11 42.21 61.75 55.57 42.11 48.0

5

43.14 39.50

10 34.96 40.32 44.20 50.68 52.19 37.18 43.3

9

39.70 37.48

11 32.16 33.25 39.89 46.66 48.16 35.45 38.3

7

37.40 36.36

12 35.07 37.33 40.45 39.82 39.40 38.45 42.7

0

39.81 41.02

13 36.94 33.91 40.03 34.03 25.20 31.44 43.4

6

41.67 41.60

14 38.78 39.76 34.62 35.66 15.76 24.86 43.1

3

37.34 37.41

15 31.06 35.07 26.52 29.04 15.90 21.54 41.8

2

23.60 26.79

16 16.64 31.00 25.37 21.65 21.68 23.79 40.8

1

22.22 21.61

17 13.11 30.83 33.79 16.30 25.42 28.76 33.1

8

27.78 35.68

18 24.95 52.17 42.68 13.54 33.78 36.59 37.1

8

30.66 54.21

Av

g

32.13 39.60 35.66 39.72 35.76 35.23 43.4

3

35.42 37.15

Table No 10: Calculated values of Collector Efficiency in day

time for mass flow rate ṁ1 (0.015 Kg/s)

Local measured data of global solar radiation incident on

inclined surface and meteorological data (Temperature) on

nine days are obtained by direct measurement at B.I.T.Sindri

campus (latitude). The hourly variation of solar intensity (I)

and ambient temperature (Ta) for the testing days are shown in

figures 2 and 3 respectively.

Figure 2: Hourly variation of solar radiation in all run days.

Figure 3: Ambient air temperature in all run days.

From the fig. 2 it is seen that for the fourth day, the solar

radiation increases to maximum value of 984.53 W/m2

at 1

pm. similar behavior have been observed during all run days.

From the fig. 3 ambient temperature exhibits the same

behavior as the solar radiation. However, they achieve their

maximum values of 47 ºC at 3 pm, and having minimum value

of 22ºC in morning at 5 am, during the period of

experimentation. Daily average values of solar radiation and

ambient temperature are obtained as 730.48W/m2 and

33.75ºC, respectively.

Figure 4: Outlet temperature Vs. Time for run days

As from the fig. 12 it is observed that the outlet

temperature of the system decreases with the increase in mass

flow rate of the air. For, mass flow rate(ṁ1), maximum outlet

temperature is 60.5 ºC, at 12 pm of second day and minimum

outlet temperature is 27ºC,at 6am in first day. For, mass flow

rate(ṁ2), maximum outlet temperature is 56 ºC, at 11am of

third day and minimum outlet temperature is 29ºC,at 5 am in

second day. Similarly for mass flow rate(ṁ3), maximum outlet

temperature is 55 ºC, at 1 pm of first day and minimum outlet

temperature is 25ºC,at 5 am in third day. So, it may concluded

that the outlet temperature increases with the decrease in mass

flow rate of air or vice versa.



ISSN: 2349-8862


Figure 5: Variation of mean temperature of absorber plate

and air stream for test day 1 of mass flow rate 0.015 Kg/s





From fig. 5, 6 and 7 it is seen that the average temperature

difference is maximum for mass flow rate of 0.015 Kg/s and it

is minimum for mass flow rate of 0.025 Kg/s. So, it is

concluded that as the mass flow rate of air increases, the mean

temperature difference of absorber plate and air stream

decreases.

Figure 8: variation of efficiency with Mass flow rate

It is shown from fig. 8 that the air heater efficiency is

strongly depends on mass flow rate; it increases with

increasing mass flow rate (ṁ). Increasing the mass flow rate

causes a consequent increase of the time average

instantaneous collector efficiency. Average efficiency of the

collector are 35.79 %, 36.91 %, and 38.66%, on three different

mass flow rate (i.e. ṁ1= 0.015 Kg/s, ṁ2=0.020 Kg/s, and ṁ3=

0.025 Kg/s) of air respectively.

Figure 9: Variation of Nusselt number with Reynolds number




ISSN: 2349-8862



Fig. 9, 10 and 11 show the variation of Nusselt number

with Reynolds number As, per the graphs it is seen that

Nusselt number is minimum (15.01778), when the Reynolds

number is minimum (4487.864) and it is maximum (26.8125),

when the Reynolds number is maximum (8807.079).So, it may

concluded that the heat transfer decreases as the mass flow

rate and Reynolds number increases.

Figure 12: Variation of convective heat transfer coefficient

with respect to Reynolds number for mass flow rate of 0.015

Kg/s.

Figure 13: variation of Convective heat transfer coefficient

with respect to Reynolds number for mass flow rate of

0.020Kg/s.

Figure 14: variation of Convective heat transfer coefficient

with respect to Reynolds number for mass flow rate of

0.025Kg/s.

Fig. 12, 13, and 14 illustrate the variation of convective

heat transfer coefficient with Reynolds number. It is seen that

convective heat transfer coefficient is maximum

(12.7708W/m2 k), when the mass flow rate(0.025 Kg/s) and

Reynolds number (8807.079).It may concluded that the heat

transfer decreases by increasing the mass flow rate. As the

mass flow rate increases, the temperature difference between

absorber plate and air stream increases, so higher the absorber

plate temperature. Higher the plate temperature leads to

increase the air viscosity. The increase in air viscosity affects

the wall shear stress and decrease the local Reynolds number

as well which cause an increase in thermal boundary layer

thickness, and results in decreasing the convective heat

transfer coefficient.

Figure 15: Variation of Friction factor with Reynolds number

for mass flow rate of ṁ1

Fig. 15, 16 and 17 shows the variation of friction factor

with Reynolds number. Friction factor attain the maximum

value, when the mass flow rate is minimum (0.015 Kg/s) and

Reynolds number is also minimum (4487.864). Same as it

attain minimum value, when mass flow rate (0.025 Kg/s) at

maximum Reynolds number (8807.079). So, it may conclude

that as the mass low rate and Reynolds number increases the

friction factor decreases, this is due more turbulence of

flowing fluid less the skin friction.



ISSN: 2349-8862






V. CONCLUSION

On the basis of the experimental results obtained for nine

run days on three different mass flow rate of air, for force

convection solar air heating system with phase change

material (Paraffin wax) energy storage, manufactured and

tested in B.I.T.Sindri, Dhanbad, Jharkhand, India, the

following conclusion can be drawn.

Air and plate temperature in general increases along the

air heater.

Air mass flow rate and solar radiation are predominant

factor which affect the performance of air heater.

Increasing the mass flow rate causes a consequent

decrease of air and plate temperatures.

This air heater is capable to produce hot air consistently

for 24 hours, the average temperature rise of 9.60 ºC, 7.19

ºC and 5.61 ºC, for all three different mass flow rate of air

respectively, from the atmospheric air temperature.

Increasing the mass flow rate causes a consequent

increase of the time average instantaneous collector

efficiency. Average efficiency of the collector are 35.79

%, 36.903 %, and 38.66%, on three different mass flow

rate (i.e. ṁ1= 0.015 Kg/s, ṁ2=0.020 Kg/s, and ṁ3= 0.025

Kg/s) of air respectively.

REFERENCES

[1] Ekechukwua O. V., Norton B.” Review of solar-energy

drying systems III: low temperature air-heating solar

collectors for crop drying applications” Energy

Conversion & Management 40 (1999) 657-667.

[2] Keith Gawlik, Craig Christensen, Charles Kutscher.“A

numerical and experimental investigation of low-

conductivity unglazed, transpired solar air heaters”. J Sol

Energy Eng 2005;127:153–5.

[3] AR Jaurker, JS Saini, BK Gandhi. Heat transfer and

friction characteristics of rectangular solar air heater duct

using rib-grooved artificial roughness. Sol Energy

2006;80:895–907.

[4] Cemil YamalI, Ismail Solmus” Theoretical investigation of

a humidification dehumidification desalination system

configured by a double-pass flat plate solar air heater”

Desalination 205 (2007) 163–177.

[5] Zambolin E., Del Col D.” Experimental analysis of

thermal performance of flat plate and evacuated tube solar

collectors in stationary standard and daily conditions”

Solar Energy 84 (2010) 1382–1396.

[6] Kostic Ljiljana T., Pavlovic Tomislav M., Pavlovic Zoran

T.” Influence of reflectance from flat aluminum

concentrators on energy efficiency of PV/Thermal

collector” Applied Energy 87 (2010) 410–416.

experimental investigation of forced circulation solar air heater along with integrated solar...

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