DESIGN, SIMULATION, CONSTRUCTION AND PERFORMANCE EVALUATION OF A THERMOSYPHON SOLAR WATER HEATER

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Author

Presented To

Department of Mechanical Engineering

145 Pages 11,119 Words 1,371 Views PDF Format No. of Chapters: 1 to 5 Chapters

ABSTRACT

A thermosyphon solar water heating system which captures and utilises the abundant solar

energy to provide domestic hot water was designed, simulated, constructed and tested. The

system was designed to supply a daily hot water capacity of 0.1m3

at a minimum temperature of

70o

C for domestic use. The design approach was in three parts; firstly, since solar radiation and

weather data which are driving function for solar systems design vary randomly with time, the

monthly average daily solar radiation and weather data obtained from the typical meteorological

year (TMY) solar data of Zaria were used to determine the design month as the month (August)

with the least monthly average daily solar energy ratio. Solar radiation and weather data of the

design month were used to design the system. Secondly, the design month solar radiations and

weather data were used as input into the design equations coded using MATLAB programming

language to determine the system characteristic and components sizes. A parametric study was

also carried out to study the effects and sensitivity of varying some design parameters such as

number of glass covers , collector tube centre to centre distance W, absorber plate thickness

, collector tube internal diameter and collector tilt angle on the design objective function

(the heat removal factor ). Thirdly, based on the values of the system characteristics and

components sizes obtained from the design calculations and the parametric study, a model for the

performance simulation of the system was formulated using the Transient System Simulation

(TRNSYS) software. This model was used to predict the annual hourly performance of the

system for recommended average day of the months using the TMY solar radiation and weather

data of Zaria as input function. The system was then constructed based on the component sizes

adopted for the simulation owing to the satisfactory performance of the system as revealed from

the simulated results. To validate the simulated system performance, system performance tests

were conducted for 3 days and the results were compared with the simulated results The root

mean square error (RMSE) and the Nash-Sutcliffe Coefficient of Efficiency (NSE) statistical

tools were used to analyse the experimental and simulated results in order to validate the

predictive power of the software The results of this research led to the conclusion that a

thermosyphon solar system with collector area of 224 m2

operated under the weather condition

of Zaria, would be capable of supplying a daily domestic water of 01m3

at temperature ranging

from 59o

C for the worst month (August) to 81o

C for the best month (April)The computed Nash-

Sutcliffe Coefficient of Efficiency (NSE) values of 0663, 0956 and 0885 and the low RMSE

values of 809o

C, 365o

C and 531o

C between the modeled tank inlet temperature and the

observed tank inlet temperature for the three days tests conducted indicated that the model

formulated using TRNSYS software was valid and closely agreed, capable of predicting the

performance of the system with a 663 %, 956% and 885 % degree of accuracy for the 3 days

that the experiments were conducted respectively

TABLE OF CONTENTS

Title Page- - - - - - - - - - - - - - - - i

Declaration - - - - - - - - - - - - - - - - ii

Certification - - - - - - - - - - - - - - - iii

Dedication- - - - - - - - - - - - - - - - iv

Acknowledgements - - - - - - - - - - - - - - - - - - - - - - v

Abstract - - - - - - - - - - - - - - - - vi

Table of Contents- - - - - - - - - - - - - - - - - - - - - - - viii

List of Figures - - - - - - - - - - - - - - ,- xii

List of Tables - - - - - - - - - - - - - - - xv

List of Appendices - - - - - - - - - - - - - - xvi

Nomenclature - - - - - - - - - - - - - - - xvii

Abbreviation- - - - - - - - - - - - - - - xxii

10 INTRODUCTION - - - - - - - - - - - - - - 1

11 Background of the Study - - - - - - - - - - - - 1

12 Statement of the Problem - - - - - - - - - - - - 3

13 The Present Research - - - - - - - - - - - - - 4

14 Aim and Objectives - - - - - - - - - - - - - - 5

15 Significance of Research - - - - - - - - - - - - - - - - - - - 5

20 LITERATURE REVIEW - - - - - - - - - - - - 6

21 Solar Potential and Resources of a Location - - - - - - - - - 6

22 Solar Water Heating Systems - - - - - - - - - - - 7

221 Direct open-loop hot water system - - - - - - - - - - - 7

222 Indirect hot water system - - - - - - - - - - - - 9

23 Solar collector- - - - - - - - - - - - - - - 10

231 Selective surfaces - - - - - - - - - - - - - - 12

232 Collector covers- - - - - - - - - - - - - 13

24 Thermosyphon System - - - - - - - - - - - - 14

25 Sizing a Solar Hot Water System- - - - - - - - - - 15

26 Collector Orientation - - - - - - - - - - - - - 16

27 Solar Water Heating System Applications - - - - - - - - - 17

271 Service hot water - - - - - - - - - - - - - 17

272 Swimming pools - - - - - - - - - - - - - 18

28 Solar Water Heating System Load - - - - - - - - - - 19

281 Average daily hot water consumption and load profile - - - - - - 19

28 2 Hot water load profile - - - - - - - - - - - - 19

29 Review of Related Work- - - - - - - - - - - - - 20

210 Theoretical Background - - - - - - - - - - - - 24

2101 Angle of incidence of beam radiation - - - - - - - - - 24

2102 Declination - - - - - - - - - - - - - - - 26

2103 Solar hour angle - - - - - - - - - - - - - - 27

2104 The sunset hour angle - - - - - - - - - - - - 27

2105 Extraterrestrial radiation and clearness index - - - - - - - 27

2106 Tilted irradiance: beam and diffuse Components- - - - - - 28

211 Transmittance-Absorptance Product - - - - - - - - - 30

212 Monthly Average Absorbed Radiation - - - - - - - - 31

30 MATERIALS AND METHODS - - - - - - - - - - 32

31 System Description - - - - - - - - - - - - - 32

32 Working Principle - - - - - - - - - - - - - - 33

33 Materials Selection - - - - - - - - - - - - - 34

331 Flat plate collector - - - - - - - - - - - - - - 34

332 Storage tank - - - - - - - - - - - - - - 36

34 Design Assumptions- - - - - - - - - - - - - 36

35 Design Considerations- - - - - - - - - - - - 37

36 Design Theories - - - - - - - - - - - - - ,- 37

361 Solar resources and weather data- - - - - - - - - ,- 37

362 Flat-plate collector- - - - - - - - - - - - - 38

363 System load calculations- - - - - - - - - - - - 46

364 System performance evaluation- - - - - - - - - - 47

37 System Design Approach and Calculations- - - - - - - - 51

371 Determination of the design month- - - - - - - - - 52

372 Determination of design parameters- - - - - - - - - 53

373 Design parameters optimisation- - - - - - - - - - 53

374 System performance simulation- - - - - - - - - - 54

38 Construction of the System- - - - - - - - - - - 55

381 Construction of the flat plate solar collector- - - - - - - 55

382 Construction of the storage tank- - - - - - - - - - - 58

383 Construction of supporting frame- - - - - - - - - - - 59

39 System Cost Estimation- - - - - - - - - - - - 60

310 Validation of Simulation Model- - - - - - - - - - 61

3101 Description of the experimental set-up- - - - - - - - - - 63

3102 Experimental procedure- - - - - - - - - - - 63

40 RESULTS AND DISCUSSION - - - - - - - - - - - - - - - - - 65

41 System Design Calculation - - - - - - - - - - - - 65

42 Collector Design Parameters Optimisation- - - - - - - - 68

421 Collector tilt angle - - - - - - - - - - - - - 68

422 Collector tube diameter and centre to centre distance - - - - - - - 69

423 Collector absorber plate thickness - - - - - - - - - - 70

424 Collector number of glazing - - - - - - - - - - - 71

43 System Optimum Parameters and Simulation - - - - - - - - 73

44 System Performance Evaluation- - - - - - - - - - - 83

45 Validation of Simulated Results - - - - - - - - - - 84

441 Comparison of simulated results with experimental results - - - - - - 84

442 Analysis of the predictive power of the simulation software - - - - 93

50 SUMMARY, CONCLUSIONS AND RECOMMENDATIONS- - - - 98

51 Summary - - - - - - - - - - - - - - - - 98

52 Conclusions - - - - - - - - - - - - - - - 99

53 Recommendations - - - - - - - - - - - - - 100

REFERENCES- - - - - - - - - - - - - - 101

APPENDICES - - - - - - - - - - - - - - - - 106

145 Pages 11,119 Words 1,371 Views PDF Format No. of Chapters: 1 to 5 Chapters

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