Mathematical Modeling of the Thermofluid Characteristics of Solar Collector for Variable Solar ...

63 Pages·2017·1.73 MB·English

Mathematical Modeling of the Thermofluid Characteristics of
Solar Collector for Variable Solar Radiation in Climatic
Condition of Bangladesh

M. Sc. in Mathematics

Submitted by
Md. Anowar Hossain
Student No: 1015092501F
Session- October 2015

Department of Mathematics
Bangladesh University of Engineering & Technology
Dhaka-1000, Bangladesh

DEDICATION

Dedicated to My Parents

iii

CONTENTS
Title Page No.
BOARD OF EXAMINERS ............................................ Error! Bookmark not defined.
DEDICATION ................................................................. Error! Bookmark not defined.
Author’s Declaration ...................................................... Error! Bookmark not defined.
ACKOWLEDGEMENT ................................................. Error! Bookmark not defined.
CONTENTS ................................................................................................................. vi
LIST OF TABLES ...................................................................................................... ix
LIST OF FIGURES ..................................................................................................... x
NOMENCLATURE ................................................................................................... xii
CHAPTER-1 ................................................................................................................. 1
Introduction .................................................................................................................. 1
1.1 Introduction .............................................................................................................. 1
1.2 Background of the study .......................................................................................... 1
1.3 Literature review ...................................................................................................... 3
1.3.1 Solar Air Heater ............................................................................................. 3
1.3.2 Solar Water Heater ......................................................................................... 5
1.4 Solar Energy of Bangladesh ..................................................................................... 7
1.5 Adsorption Process .................................................................................................. 8
1.5.1 Adsorption ...................................................................................................... 8
1.5.2 Adsorption Theorem ...................................................................................... 9
1.5.3 Adsorbate ....................................................................................................... 9
1.5.4 Adsorbent ..................................................................................................... 10
1.5.5 Some Definition and Application of adsorption related areas ..................... 10
1.6 Solar Collectors ...................................................................................................... 11
1.6.1 Flat plate collectors (FPC) ........................................................................... 11
1.6.2 Stationary compound parabolic collectors (CPC) ........................................ 12
1.6.3 Evacuated tube collectors (ETC) ................................................................. 13
1.7 Outline of the Chapters .......................................................................................... 14

vi
CHAPER-2 ................................................................................................................. 15
Theoretical Modeling ................................................................................................. 15
2.1 Introduction ............................................................................................................ 15
2.2 The Mathematical Model Development of a Flat–Plate Solar Collector System .. 15
2.2.1 The glass cover ............................................................................................. 17
2.2.2 The air gap between the cover and the absorber .......................................... 18
2.2.3 The absorber ................................................................................................. 18
2.2.4 The insulation ............................................................................................... 19
2.2.5 The working fluid ......................................................................................... 20
2.2.6 The storage tank ........................................................................................... 21
2.3 The Numerical Solution For The Solar Collector Mathematical Model ............... 21
2.4 The Heat Transfer Correlations ............................................................................. 24
CHAPER-3 ................................................................................................................. 26
Methodology and validation ...................................................................................... 26
3.1 Introduction ............................................................................................................ 26
3.2 Analysis of the previous work ............................................................................... 26
3.2.1 Convergence Study ...................................................................................... 26
3.3 Reproduction of the reported result for the purpose of verifications and
validation of the present study .............................................................................. 29
3.4 Results on outlet temperature in climatic condition Bangladesh ........................... 30
3.5 Findings and conclusion: ....................................................................................... 32
CHAPER-4 ................................................................................................................. 33
Effect of variable solar radiation .............................................................................. 33
4.1 Introduction ............................................................................................................ 33
4.2 Climatic condition of Bangladesh .......................................................................... 33
4.3 Use of constant solar radiation ............................................................................... 33
4.3.1 Outlet Temperature due to constant solar radiation ..................................... 33
4.4 Solar Radiation in Bangladesh ............................................................................... 35
4.5 Use of variable solar radiation ............................................................................... 35
4.5.1 Effect for variable solar radiation on outlet temperature in summer
season ............................................................................................................ 37
4.5.2 Effect for variable solar radiation on outlet temperature in rainy season .... 44
vii
4.5.3 Effect of variable solar radiation in dry winter season ................................ 45
4.6 Finding and Conclusion ......................................................................................... 46
CHAPER-5 ................................................................................................................. 47
Conclusion ................................................................................................................... 47
5.1 Summary of the work ............................................................................................. 47
5.2 Future work ............................................................................................................ 47
References ................................................................................................................... 48

viii
LIST OF TABLES
Table No. Caption Page No.
Table 4.1 The climate data of sunrise time, sunset time, average maximum radiation,
maximum temperature and minimum temperature in Dhaka, Bangladesh . 36

ix
LIST OF FIGURES
Figure No. Caption Page No.
Figure 1.1: Installation of solar home system in Bangladesh ........................................ 8
Figure 1.2: A typical flat plat solar collector ............................................................... 12
Figure 1.3: Stationary Compound Parabolic Collectors (CPC) ................................... 13
Figure 1.4: Evacuated tube collectors (ETC) ............................................................... 14
Figure 2.1: Sketch of the five nodes analyzed in the flat-plate solar collector model . 15
Figure 2.2: 1-D heat transfer in the cover .................................................................... 17
Figure 2.3: 1-D heat transfer in the air gap between cover and absorber .................... 18
Figure 2.4: 1-D heat transfer in the absorber ............................................................... 19
Figure 2.5: 1-D heat transfer in the insulation ............................................................. 19
Figure 2.6: Energy balance in a control volume of the working fluid in flat-plate solar
collector ...................................................................................................... 20
Figure 2.7: Storage tank control volume ...................................................................... 21
Figure 3.1: Outlet temperature histories for different number of nodes at 1.5 GPM .. 27
Figure 3.2: Outlet temperature for different input solar radiation ............................... 27
Figure 3.3: Temperature histories for all the analyzed cross section (node 24) .......... 28
Figure 3.4: Outlet temperature for different input solar radiation ............................... 29
Figure 3.5: Output temperature histories for all the analyzed cross section ................ 30
Figure 3.6: Outlet temperature for different input solar radiation in Bangladesh ....... 31
Figure 3.7: Output temperature histories for all the analyzed cross section in climatic
condition of Bangladesh ............................................................................ 31
Figure 4.1: Maximum raised Inlet and Outlet temperature for 1.5 GPM .................... 34
Figure 4.2: Maximum rises of Temperature of all sections of the collector (1.5 GPM)
.................................................................................................................... 34
Figure 4.3: Monthly average radiation in Dhaka, Bangladesh. ................................... 36
Figure 4.4: Inlet and Outlet temperature for variable solar radiations......................... 38
Figure 4.5: Outlet temperature history at different flow velocity. ............................... 38
Figure 4.6: Outlet temperature history for different amount of working fluid. ........... 39
Figure 4.7: Inlet and outlet temperature history for 1 hour interval. ........................... 40
Figure 4.8: Outlet temperature history for different flow rate. .................................... 41
Figure 4.9: Outlet temperature history for different amount of working fluid. ........... 41
Figure 4.10: Outlet temperature history for different time interval. ............................ 42
Figure 4.11: Inlet and outlet temperature for the flow rate 0.7GPM in summer season.
................................................................................................................. 43
Figure 4.12: Inlet and outlet temperature for the flow rate 0.7 GPM in rainy season. 44
Figure 4.13: Inlet and outlet temperature for the flow rate 0.7 GPM in winter season.
................................................................................................................. 45
x