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CLOSE THIS BOOKSolar Water Heaters in Nepal (SKAT, 1979, 142 p.)
PART V ANNEX
VIEW THE DOCUMENT8. ANNEX

Solar Water Heaters in Nepal (SKAT, 1979, 142 p.)

PART V ANNEX

8. ANNEX

8.1 CHECKLIST FOR SOLAR WATER INSTALLATIONS

1) Careful site selection. Check for full sunshine throughout the year.

2) Structure to hold weight of system.

3) Water supply: Sufficient quantity and pressure (head).

4) Continued accessibility of installation (collectors, tank) for maintenance and repairs.

5) Cold connection to supply pipeline to prevent return of hot water into cold water pipeline, (e.g. non-return valve or separate pipeline from feed or roof tank).

6) Safety valve or vent pipe for over pressure release (due to expansion of hot water).

7) Ventilation of system: Requires gradient in circulation pipes and an air release valve or a vent pipe on top of the hot water storage tank.

8) Slopes in pipelines, to avoid blockages of flow through air bubbles. Avoid U-bend installations (especially in low-pressure supply systems).

9) Insulation requirements for hot water storage tank, circulation pipes and for hot water pipelines.

10) Drainage facility (tap, cap) for drainage of entire system.


Four common installation mistakes

1st mistake: Distance between storage tank and collector is too small-circulation can reverse during the night, which means great heat loss!

2nd mistake: Cold-and hot water pipe connections are mixed up-cold-and hot water layer are disturbed which results in low water temperature!

3rd mistake: U-bent in collector circuit-air accumulates and interrupts the circulation, which means no heating at all!

4th mistake: Distance between rooftank and storage tank is too small-below a certain level in the rooftank the storage tank is not refilled, which means hot water doesn't flow!

8.2 LEAFLET SOLAR SYSTEM

The natural circulation system is driven by one fundamental principle: hot water is lighter than cold water and tends therefore to rise.

The figures to the side show, how the system cleverly uses this principle to avoid any moving parts except the water.

The sun heats the water in the collector, which starts to rise and accumulate at the top of the storage tank. It is replaced by cold water from the bottom of the tank.

As long as the collector water is hotter than the storage tank water, it keeps circulating. Hot and cold water in the storage tank will not mix. Always the hottest water is the top layer. Therefore during night, when the collector is cold, the circulation will not reverse. Never the hot water can sink down to the cold collector.

If hot water is consumed it is always the hottest water in the storage tank, as the hot outlet is at the very top. The consumption is replaced by cold water from the rooftank. This water has to enter at the bottom of the storage tank so it will not disturb the hot and cold water layers.


FIGURE

Essentials

-Storage tank has to be higher up than the collectors, the roof tank has to be higher up than the storage tank.

-Heating circuit: Cold water leaves the storage tank at the bottom and enters the collector at the bottom. Hot water leaves the collector at the top and enters the storage tank at about 2/3 in highs.

-Consumer circuit: Hot water leaves the storage tank at the top and is replaced by cold water from the roof tank entering at the bottom.

Solar collector, MTC-SC-85

Datas:

Vertical pipe type and overall size

1810 x 1 10 mm

Collector effective area

1.22 m²

Weight

47 kg (empty)

Contain of water

3.9 ltr.

Test pressure

10 bar

Working pressure

5 bar

Absorber

36 fins alu. sheet 0.5

Absorber surface

Black colour paint

Collector box / frame

Galvanized steel sheet 0.55

Collector box inside / outside

1 coat painted

Cover

Single glass 4 mm

Insulation back/side

50 mm fibreglass

THREADS AND FORMULAS

8.3 SHEET-METAL AND STEEL PIPES

Drill diameter for

For metric threads

For whitworth threads

Thread size

Through hole

Threaded hole

Thread size

Through hole

Threaded hole

M3

3 6

2 5

1/4"

7.4

5 0

M4

4 8

3.3

5/16"

9.5

6.4

M5

5 8

4 2

3/8"

11.5

7.7

M6

7.0

5.0

7/16"

13.0

9.25

M8

9 5

6 7

1/2"

15.0

10 25

M10

115

84

5/8"

18.0

1325

M12

140

100

3/4"

22.0

16.25

Circle and cylinder

A =pi/4 D²
Area = pi/4 x Diameter x Diameter

C = pi r² = 0.785 D²

C= p D

Circumference

=pi x Diameter


= 3.142 D


= 2 pi r

V = A × h

V = A0 x h

V= pi /4 x D² x h

Lateral area of the cylinder

Al = pi x D x h


FIGURE

8.4 STEEL DIMENSIONS AND WEIGHT

MS-flat

Width mm

Thickness mm


3

4

5

6

7

8

10

12

14

10

0,236

0,314

0,393

0,471+

0 550+

0,628+




12

0,283

0,377

0,471

0,565

0 659 +

0,754

0,942 +



15

0,353

0,471

0,589

0,707

0,824 +

0,942

1,18

1,41 +


16

0,377

0,502

0,628

0,754

0,879 +

1,00

1,26

1,51 +


18

0,424

0,565

0,707

0,848

0,989 +

1,13

1,41

1,70 +

1,98 +











20

0,471

0,628

0,785

0,942

1,10

1,26

1,57

1,88

22,20

22

0,518 +

0,691

0,864

1,04

1,21

1,38

1,73

2,07

22,42+

24

0,565 +

0,754 +

0,942+

1,13+

1,32+

1,51 +

1,88+

2,26+

2,64+











25

0,589

0,785

0,981

1,18

1,37

1,57

1,96

2 36

2,75

27

0,636 +

0,848 +

1,06

1,27 +

1,48 +

1,70 +

2,12 +

2 54 +

2,97 +

28

0,659 +

0,879 +

1,10 +

1,32 +

1,54 +

1,76 +

2,20 +

2,64 +

3,08 +

30

0,707

0,942

1,18

1,41

1,65

1,88

2,36

2,83

33,30+











32

0,754 +

1,00 +

1,26 +

1,51 +

1,76 +

2,01 +

2,51 +

3,01 +

3,52 +

35

0,824

1,10

1,37

1,65

1,92

2,20

2,75

3,30

33,85 +

40

0,942

1,26

1,57

1,88

2,20

2,51

3,14

3,77

44,40 +

45

1,06

1,41

1,77

2,12

2,47

2,83

3,53

4,24

44,95 +











50

1,18

1,57

1,96

2,36

2,75

3,14

3,93

4 71

5,50+

55

1,30

1,73

2,16

2,59

3,02

3,45

4,32

518

66,04 +

60

1,41

1,88

2,36

2,83

3,30

3,77

4,71

5,65

66,59 +

65

1,53

2,04

2,55

3,06

3,57

4,08

5,10

6,12

77,14


FIGURE

Round bar

d

cm²

kg/m

d

cm²

kg/m







5 +

0,196

0,154

9

0,636

0,499

5,5

0,238

0 187

9,5+

0,709

0,556

6

0,283

0 222

10

0,785

0,617

6,5 +

0,332

0,260

10,5 +

0,866

0,680







7

0,385

0 302

11

0,950

0,746

7,5 +

0,442

0 347

11,5

1,04

0,815


0,503

0,395

12

1,13

0,888

8,5 +

0,568

0,445

12,5 +

1,23

0,963


FIGURE

Angle iron

Size

a x b

Thickness

cm²

kg/m

Size

a x b

Thickness

cm²

kg/m

15

15

3

0,82

0,640

40

40

3 +

2,35

1,84





40

40

4

3,08

2242


20

20

3

1,12

0,880

40

40

5

3,79

297

20

20

4

1,45

1,14

40

40

6

4,48

3,52






40

40

7 +

5,13

4,03

25

25

3

1,42

1,12

40

40

8

580

4 55

25

25

4

1,85

1,45






25

25

5 +

2,26

1,77

45

45

3 +

2,66

2,09






45

45

4

3,49

22,74

30

30

3

1,74

1,36

45

45

5

4,30

3,38

30

30

4

2,27

1,78

45

45

6

509

4 00

30

30

5

2,78

2,18

45

45

7

586

4 60

30

30

6

3,27

2,57











50

50

4+

3,89

33,06

35

35

3+

2,04

1,60

50

50

5

4,80

3,77

35

35

3,5+

2,33

1,87

50

50

6

5,69

4,47

35

35

4

2,67

2,10

50

50

7

6 56

515

35

35

4,5

2,93

2,30

50

50

8

7,41

582

35

35

5

3,28

2,57

50

50

9

824

647

35

35

6

3,87

3,04






8.5 SHEET-METAL

Convertion table for sheet thickness

Thickness

Thickness

Thickness

Thickness

in ISWG

in mm

in ISWG

in mm

30

0.314

19

1.015

29

0.345

18

1.218

28

0.376

17

1.422

27

0.416

16

1.625

26

0.457

15

1.828

25

0.507

14

2.040

24

0.558

13

2.337

23

0.609

12

2.641

22

0.711

11

2.946

21

0.812

10

3.250

20

0.914




FIGURE

Steel sheet

Plate thickness

Weight kg/m²

size of plate



100 x 2000 mm

1250 x 2500 mm

in mm


weight in kg

0.5

4

8

12.5

0.62

5

10

16

0.75

6

12

19

087

7

14

22

1

8

16

25

1.25

10

20

31

1.5

12

24

38

1.75

14

28

44

2

16

32

50

2.5

20

40

63

3

24

48

75

3.5

28

56+

88+

4

32

64

100

5

40

80

125

6

48

96

150

7

56

112

175

8

64

128

200

9

72

144+

225+

10

80

160

250

Alu. sheet

Plate

Weight

Size of plate

thickness

kg/m²

1000 x 2000 mm


in mm

weight in kg

0.5

1.35

5.4

0.75

1.62

-

0.80

2.18

-

Copper sheet

0.5

4.45

8.9

0.55

4.90

9.8

0.6

5.35

10.70

0.7

6.25

12.5

8.6 ADDRESSES OF SUPPLIERS

1) Air vent valve "TACO"

TACO Armaturen AG

(also heat exchangers,

Buckhauserstrasse 40

solar modules, etc.!

Postfach 1381


CH-8048 Zurich/Switzerland)

2) Differential-Thermostat

W. Kuster AG

type "RT" (Bimetal-

Parkstrasse 6

switching) DANFOSS)

4402 Frenkendorf/Switzerland



3) 12 V/DC circulation

R. Brun

pump ARWA vortex

Alternative Energy Technologies

(and other solar

95 Ruefa

appliances)

CH-7015 Tamins, Switzerland

SOLAR WATER HEATERS FURTHER READINGS:

1) Guidelines for the cost-effective design of solar water heating collectors
by A W K McGregor, Senior Lecturer
Dept. of Mechanical Engineering
Napier College, Colinton Road
Edinburgh EH10 5DT, Scotland, U.K.

2) Solaranlagen
von H. R. Schmidli, Berufsschullehrer,
erhaeltlich: SSIV, Postfach, Ch-8023 Zuerich, Switzerland

3) Le chauffe-eau solaire
de Thierry Cabirol et al.
EDISUD, La Calade, F-13090 Aix-en Provence, France

4) Agua caliente solar (Original: practical solar heating)
1978: Kevin McCartney -Prism Press, Chalmington, Dorchester
1980: H. Blume Ediciones, Rosario, 17, Madrid -5, Spain

5) Plumbing, hot water supply and heating systems
by F. Hall (1986)
Longman Scientific & Technical, Longman House,
Burnt Mill, Harlow, Essex CM20 2JE, England, U.K.

6) Plumbing and heating
by F. Hall (1980)
The Macmillan Press, Ltd, London and Basingstoke

7) Drinking water installations and drainage requirements in Nepal
by A. Bachmann and H. Waldvogel
a publication by MTC-Nepal and Skat-Switzerland
SKAT, Varnbuelstrasse 14, CH-9000 St. Gallen, Switzerland

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