VELUX Solar hot water system

VELUX Solar hot water system

Solar excellence by design

The complete solution from VELUX

While everyone wants a home that is warm and comfortable, increasingly people are also looking for optimum energy efficiency.

And with ever expanding awareness of the impact of energy consumption on the environment, there is demand for environmentally-friendly energy solutions.

The VELUX Solar Hot Water Solution combines our flair for exceptional roof products with energy produced by the sun to create an integrated water-heating system that is ideal for new and existing properties.

Employing exceptional design standards, it is a complete system that is easily integrated into good house design, conforming with the latest Government renewable energy initiatives and comes with the kind of guarantee package that you would expect from a world-class company like VELUX.

Like all VELUX products, it is manufactured to the highest standards, is easy to work with, and the entire integrated system is supplied as a single stock item ready to be installed.

Efficiency with style

It is not just the ever-increasing cost of conventional fuel that has forced consumers and home builders to consider alternative ways of meeting their energy needs.

Government directives such as the Code for

Sustainable Homes have placed the issue high on the house design agenda.

Rising awareness of the impact of climate change has encouraged people to do their bit for the environment and make the most of renewable sources of energy.

The VELUX solar hot water system takes advantage of the sun’s natural energy and can typically provide for up to 70% of a home’s hot water requirements. While this has a dramatic impact on fuel bills it is also beneficial for the environment.

The system is not just about energy efficiency. It is also about great design.

The roof-based energy collectors use a standard VELUX window flashing kit and, like a VELUX roof window, they are integrated into the roof. They can even be combined with VELUX roof windows.

Photography courtesy of Summerfield Homes.

Like all VELUX products, the system enjoys the highest levels of functionality. Utilising the very latest technology the VELUX solar hot water system has been produced using high quality and durable materials. Naturally it has been thoroughly tested and the system meets or exceeds a number of independently assessed standards, including WRAS certification for the solar hot water tank.

The real beauty of the system is that VELUX has thought of everything. It is very much a complete system. Every part of it is compatible and it all works together for optimum efficiency.

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4

Better by design

If you are familiar with the VELUX product range, you will be aware of the startling array of possibilities that our products bring to house design. VELUX is the world leader in roof window design with over

50 years’ experience of creating roof windows that are both visually attractive and extremely functional.

The solar hot water system conforms to the company’s exceptional design standards. The VELUX solar collector design ensures a perfect fit with newly built homes. It is integrated within the roofing material and provides a harmonious fit with traditional architecture and the latest in renewable energy technology.

As with all other plumbing, the pipes and fittings are neatly concealed within the external envelope of the building, ensuring an uncluttered roofline.

When it is installed, the solar collector integrates into the roof just like a VELUX roof window. Available in four different sizes and using standard flashings, it can even be combined with existing or new

VELUX roof windows to ensure a visually attractive roof design.

In older buildings, it is easy to incorporate too. Whether it is being fitted alongside roof windows or on its own, the integrated design means that planning and ordering are easy.

Quality you can trust

All VELUX products are produced with the best available materials. VELUX solar systems are no exception to that rule and are produced with premium quality materials that allow for high performance, trouble-free installation and outstanding durability.

The specification of the solar collector itself is the result of many years of rigorous testing and product design combined with our experience of producing roof products throughout Europe.

The system meets all of the independently assessed standards. The solar collectors are independently certified to EN12975 for durability, reliability and performance.

The solar collectors also hold the Solar

Keymark – the quality label for solar thermal products, based upon European norms and certified by CEN. This is the customer’s guarantee that a solar thermal product is in accordance with European norms with regards to quality, product information, and that the product complies with rules of subsidy in most European countries.

Naturally, the system also meets British standards. The plumbing elements are

WRAS certified and electrical elements all CE marked.

5

6

Everything you need from a single source

All of the various component parts of the

VELUX solar hot water system fit together perfectly and are supplied together in one package by your VELUX merchant.

All you have to do is choose the appropriate solar collector(s) and tank size and the complete system will be delivered in its entirety.

As the system supplies up to 70% of a home’s hot water requirements, it has been designed to integrate easily with the heating system within the home. The solar tank is compatible with most types of auxiliary heating, such as gas, oil or solid fuel boilers.

If these are not available then the tank can be supplied with an immersion heater to provide hot water when there is little or no solar gain.

Solar collector

Auxiliary heating

Solar hot water tank

Hot water

A complete packaged solution for renewable energy

• Complete solar system for hot water

• Supplies up to 70% of hot water demands

• Compatible with most types of back-up boiler

• Easy to specify, order and install

• Maximises free energy from the sun

• An ideal renewable energy solution for new developments and building renovations

Cold water

Typical solar hot water system Up to 2 people 3-4 people 5-6 people

Solar collector(s)

Collector area (gross)

Flashings suitable for profiled or slate roof

Connection pipes

Solar tank

Volume

Weight

Dimensions (d x h)

Control unit/pump station

Safety mixer valve

Expansion vessel(s)

Micro bubble air separator

Glycol

Flexible flow and return pipes

Underfelt sealing collars

1 x U12

2.5m

2

!

TFF 200 0201

180 litres

85 kilos

540 x 1432mm

!

!

!

!

!

10m

!

2 x U12

5m

2

!

!

TFF 300 0201

280 litres

120 kilos

600 x 1794mm

!

!

!

!

!

10m

!

3 x U12

7.5m

2

!

!

TFF 400 0201

375 litres

140 kilos

700 x 1591mm

!

!

!

!

!

10m

!

The VELUX solar hot water system is one complete system, the table below details all of the components.

Component list for the VELUX solar hot water system

Description Vented

Solar collector(s)

Thermostat

Flexible flow and return pipes

Connection pipes

Underfelt sealing collars

Micro air bubble separator

Flashings suitable for profiled or slate roof

!

!

!

!

!

!

!

Solar tank

Factory fitted temperature and pressure release valve

Factory fitted dual control cutout thermostat

Two motorised valves

Pressure reducing valve

Check valve

Expansion valve

Tundish

!

Expansion vessel(s)

Safety mixer valve

Glycol

Control unit/pump station

!

!

!

!

!

!

!

!

!

!

!

!

Unvented

!

!

!

!

!

!

!

!

!

!

!

7

8

VELUX solar collectors

Outstanding durability, high performance and easy installation

The VELUX solar collectors are the product of many years of painstaking research.

They have been designed for trouble-free installation, high performance and outstanding durability. These collectors are integrated into the roofline using standard VELUX flashings. Once they are installed they capture the sun’s energy and use it to heat water in the home.

The combination of a special transparent solar glass with the copper absorber ensures that the system is extremely efficient.

VELUX solar collectors (variant 4000)

The collector casing is produced from maintenance-free aluminium and incorporates a thick layer of high-density mineral wool insulation, giving unrivalled performance and longevity.

The copper absorber in the collector is produced with a selective surface, which gives the VELUX collector an extraordinarily high efficiency.

Using state of the art laser technology, the absorber plate is attached to the register tubes with no visible welding stripes.

Installation of several solar collectors is simple:

VELUX flexible pipes allow multiple combinations of solar collectors.

A special transparent solar glass with very high light transmittance ensures that the VELUX collector has one of the best performances on the market. The solar collector is elegantly finished and secured with the maintenance-free

VELUX aluminium cladding concept.

The solar collectors are built into the roof with standard VELUX flashings, providing a safe and tight roof integration. Also, the flashings are perfectly suited to combining solar collectors and VELUX roof windows.

Collector technical details

Weights

Gross Weight (kg)

Net Weight (kg)

Areas

Efficiency

Gross area (m

2

)

Aperture area (m

2

)

Absorber area (m

2

)

Litres

Max operation pressure (bar)

Test pressure (bar)

Heat capacity (kJ (m

2

K))

Angle Factor (K dir

50°)

Stagnation temperature (°C) eta a

1

0 a

2

(start efficiency)

[W/(m

2

K)]

[W/(m

2

K

2

)]

MO8

29

26

1.2

0.9

0.9

0.9

6

10

8

0.93

185

0.7970

4.1770

0.0039

VELUX solar collectors (variant 4000)

SO6 S08

36

33

41

38

1.4

1.2

1.2

1.3

6

1.7

1.4

1.4

1.5

6

0.7900

3.7560

0.0073

0.7900

3.7560

0.0073

A variety of collector sizes are available and they have been tested in accordance with EN12975. Results can be found in the table above.

Collector size

The VELUX solar hot water system is highly adaptable to your own specific requirements. Currently we have four different collectors, the details of which are included in the table below.

CLI

M08

4000

CLI

S06

4000

CLI

S08

4000

Collector Code

CLI MO8 4000

CLI SO6 4000

CLI SO8 4000

CLI U12 4000

Gross area*

1.16m

1.42m

1.68m

2.51m

2

2

2

2

*measured from the external outer edges of the collector.

U12

64

59

2.5

2.2

2.2

2.2

6

10

7.4

0.95

190

0.7900

3.7560

0.0073

CLI

U12

4000

Size (mm) width

9

VELUX solar hot water tanks

Exceptional design, maximum efficiency

VELUX solar tanks are manufactured from sheet steel. Any part of the tank that comes into direct contact with water is protected against corrosion, bacteria and lime-scale deposits by an environmentally friendly enamel coating. This coating has been tested by WRc-NSF in accordance with BS6920 section 2.6.

Minimum heat loss is assured by the use of CFC-free foam insulation, ensuring optimal solar energy storage. The tank also features a unique control system that operates the pump to ensure maximum solar gain from the collectors.

VELUX solar tanks are also easy to connect to existing heating systems.

VELUX solar tank key features:

• High system efficiency and attractive design

• Optimal temperature stratification

• Easy installation due to a pre aligned pump and control unit

• Easy commissioning due to optimised factory settings

Available for vented and unvented systems

Variants of the VELUX solar water hot water system are available for both vented and unvented systems.

Vented systems rely on the water being fed into the cylinder and kept under pressure via a gravity fed header tank typically sited in the loft.

When the water in the cylinder is heated it expands and the expanded water is taken up and into the header tank.

Unvented systems are fed and pressurised with water direct from the mains. The expansion and contraction of the water when it is heated and cooled is controlled by an expansion vessel fitted to the cylinder.

Make sure that you specify whether you require a vented or an unvented system so that it will integrate with the rest of the plumbing arrangements within the property.

10

To hot tap

Motorised valve

Expansion valve

Pump

Water tank

Hot water cylinder

Vented

Motorised valve

Expansion valve

Pump

Hot water cylinder

To hot tap

Mains cold in

Unvented

The thermal store

A

WW

HV

FH

Z

HR

EHP

SV/SR

F

FS

KW

A = Anode

EHP = Sleeve for electrical heating element

F = Maintenance cover

WW = Hot water outlet

HV = Auxiliary heating flow

FH

Z

HR

= Auxiliary thermostat pocket

= Thermal cutout

= Auxiliary heating return

FS

KW

= Solar thermostat pocket

= Cold water inlet

SV/SR = Solar flow/solar return

Unique controls and optimum connectivity

The controls on the VELUX hot water storage tank are uniquely designed to operate the pump to maximise solar gain from the collectors.

The controller has been designed with many features and components that are highly adaptable for future additions to the system, or indeed emerging solar technology.

Straightforward installation and servicing

The VELUX tanks are very easy to install and to service. A full manual for connecting and commissioning the tank is supplied with the system.

The tank should only be assembled and installed by a competent tradesman.

11

Tank dimensions

Diameter, insulated

Height, insulated

Tilted height

Weight

Storage capacity

Mass of unit when full

12

Tank specifications (unvented)

Maximum permissible water pressure

Maximum permissible heating pressure

Maximum permissible solar loop pressure

Maximum permissible operating temperature water

Maximum permissible operating temperature heating

Maximum permissible operating temperature solar loop

Upper heating/reheating register

Lower heating area/solar register

Solar exchanger volume

Heating system heat exchanger volume

Performance indicator

NL top

Performance indicator

NL bottom

Auxiliary heating flow, HV

Auxiliary heating return, HR

Solar flow, SV

Solar return, SR

Hot water outlet, WW

Cold water inlet, KW

Thermal cutout, Z

Sensor thermometer wells

Auxiliary thermostat pocket, FH

Solar thermostat pocket, FS

Sleeve for electrical heating element (1

1

2

), EHP

Thermometer, T

Flange F, Di/TK/Do

Anode, A

Maximum water supply pressure to the pressure reducing valve

Operating pressure

Expansion vessel charge pressure

Expansion relief valve setting

Storage capacity

Mass of unit when full

Set opening pressure (bar) of the combined temperature and pressure relief valve(s)

The set opening temperature (degrees centigrade) of the temperature relief or temperature and pressure relief valve(s)

R mm

R mm

R mm mm mm bar bar bar bar litres kg

R mm mm mm mm mm mm mm

°C

°C

°C m

2

Units bar bar bar m

2 l l

NL

/kW

NL

/kW

R mm

R mm

R mm bar

°C

Units mm mm mm kg litres kg

TFF 200 0201 GB

540

1432

1530

85

180

285

TFF 300 0201 GB

600

1794

1930

120

280

420

TFF 400 0201 GB

700

1591

1745

140

375

540

1"

687

0.75"

1369

0.75"

55

0.5"

900

Ø 16 x 200

1012

292

737

1226

110/150/180

Ø 26 x 550

Top

16

3

3

6

180

285

TFF 200 0201 GB

5.5

5.5

5.5

95

110

110

0.70

0.95

6.4

4.8

2.4/25

4.2/31

1"

1147

1"

787

1"

687

7

90

TFF 300 0201 GB

5.5

5.5

5.5

95

110

110

0.81

1.49

10.4

5.6

2.5/27

4.1/45

1"

1424

1"

1064

1"

965

1"

965

1"

1728

1"

90

0.5"

1179

Ø 16 x 200

1289

378

1015

110/150/180

Ø 26 x 1100

Top

16

3

3

6

280

420

7

90

TFF 400 0201 GB

5.5

5.5

5.5

95

110

110

1

1.83

12.8

6.9

5.7/31

9.4/51

1"

1355

1"

1007

1"

909

1"

909

1"

1526

1"

55

0.5"

1112

Ø 16 x 200

1224

324

957

110/150/180

Ø 26 x 900

Top

16

3

3

6

375

540

7

90

Components of the hot water system

Pump station

1 Flow ball valve with integrated gravity brake

(20mbar), assembly dimension 135mm

2 Return ball valve with integrated gravity brake

(20mbar), assembly dimension 135mm

3

4

5

Pressure gauge

Solar safety valve, 6 bar, TÜV-certified

Circulation pump ST 20/6

6

7

8

Fill/drain fitting

Flow indicator 1-13l/min, swivel nut G1 x Ø 22

Air jet with manual venting nipple

9 Manual venting nipple

10 Immersion sleeve

1

2

"

11 Membrane expansion connection

12 Dial thermometer

13 Insulation shell

15 Flat 1" underfelt sealing collar

22 Tank connection pipe for pump station

The VELUX solar hot water system has a multi-functional solar thermal pump station which has been designed specifically for high temperatures.

It features variable speed settings, a built in flow indicator, and dual gravity brakes to prevent back flow of solar fluid. To ease installation, the pump station can be either tank or wall mounted. The pump station comes complete with bespoke insulation cover for thermal efficiency and protection. It also has a built in pressure gauge and safety pressure release valve for the solar circuit.

13

14

Programmer

ARR 1 Symbol

S1

S2

S3

S4/TRF

R1

Specification

Collector sensor

Store sensor lower

Store sensor at the top (optional)

Sensor for heat quality measurement (optional)

Solar pump

R1

S4/TRF

S1

1

S1

2 3

S2

4 5

S3

6 7

S4

8 12 13 14

N R2 N R1 N L

15 16 17 18 19 20

S3

S2

The VELUX solar hot water system has a user friendly, universal solar system controller. It has preset controls and clearly shows the varying temperatures between the solar collectors and the hot water tank. It can also indicate the accumulated hours of solar thermal gain. This programmer has the capacity to control multi solar circuits including space heating, and can be set to a variety of different languages. It incorporates a fault diagnostic programme should any problem occur.

Flexible flow and return pipes

These flexible stainless steel tubes connect the solar collectors to the tank, which allows quick and simple installation of the flow and return pipes. Arriving pre-insulated, they are capable of handling temperatures ranging from +175°C down to -40°C. The standard package provides these in ten metre lengths, although there are other sizes available.

Underfelt sealing collar

Self adhesive underfelt collars are supplied to ensure a perfect fit around the flexible flow and return pipes when they pass through the roofing membrane. These will assist with both the thermal performance and air tightness of the property.

Safety mixer valve

A temperature sensitive safety mixer valve is supplied with every solar package. This ensures that only the desired temperature of hot water is delivered to the taps. It can be set to temperatures ranging from 35°C to 65°C.

Micro air bubble separator

As with all closed circuits, it is possible for small amounts of air to become trapped during installation. A unique micro bubble air separator is supplied with all solar packages to facilitate the removal of this trapped air. The separator is self adjusting and requires no maintenance.

The unique valve mechanism is guaranteed not to leak. As solar circuits can reached extremely high temperatures, the separator is designed to withstand temperatures up to 180°C.

15

Performance

16

Well-positioned for optimum performance

Because the system performance depends on the solar collector being able to take advantage of available sunlight, the collector’s physical location is crucial in determining efficiency. However, the collector does not need to be facing due south in order to work effectively.

The map on the left and the table below provide an approximate guide to the technical performance of the system. As with all solar systems, there are a number of factors that influence both its ability to produce solar thermal energy and its overall efficiency.

Solar thermal energy efficiency depends on geographical location, polar orientation and pitch of the roof.

The system’s overall effectiveness will also be influenced by the efficiency of the auxiliary heating source, and the household’s daily rate of hot water consumption.

For simplicity, we have selected four cities to represent the different meteorological zones on the map. Using the stated solar irradiation at these points we are able to calculate the savings achieved by a typical VELUX solar hot water system.

Performance of a typical VELUX solar hot water system

For the purposes of demonstrating performance, VELUX has split the country into four regional areas: North (Glasgow), Mid North (Manchester), Mid South

(Cambridge) and South (Southampton) so that a reasonable comparison can be made.

Annual solar irradiation in the 4 regional areas

Region 1 North

Region 2 Mid North

Region 3 Mid South

Region 4 South

Glasgow

Manchester

Cambridge

Southampton

1032 kWh/m

1109 kWh/m

2

1160 kWh/m

2

2

1286 kWh/m

2

Performance of a typical system

Using the above information, and following a recent study that showed the typical consumption of daily hot water (DHW) per household in the UK is between 30 and

50 litres, at a temperature of 55°C per person, the total benefit of the VELUX solar hot water system per region is:

Region 1 North

Region 2 Mid North

Region 3 Mid South

Region 4 South

Glasgow

Manchester

Cambridge

Southampton

2681 kWh/year

2874 kWh/year

3003 kWh/year

3222 kWh/year

A typical VELUX solar hot water system: four person household (5m

2 of solar collectors 280 litre tank) due south orientation with 80% efficient gas boiler.

It is essential to consider the following when designing a solar hot water system

• Occupancy level

• Geographical area

• Polar orientation

• Pitch of roof

• Efficiency of auxiliary heating

• Size of collector area

Annual solar irradiation on 40° pitch, facing due South

W/m

2

1150

1100

1050

1000

950

900

1400

1350

1300

1250

1200

Orientation of the collectors

The following tables demonstrate the performance of the VELUX solar hot water system in the four chosen regions. Each table shows the direction of the roof and its pitch (or inclination). These tables show that solar energy is a viable option as a renewable energy source in the UK.

For example, in region 1, a collector facing South at a pitch of 40° will achieve 100% performance. However a collector facing WSW at a pitch of 30° will achieve 88% efficiency.

In new build cases, these factors can be taken into consideration at design stage and the orientation and design of the roof pitch can be adjusted for optimum efficiency. In renovation projects, the data serves as a guide to calculating the approximate savings available.

Orientation

65

70

75

80

85

90

40

45

50

55

60

Pitch

0

5

10

15

20

25

30

35

Performance Factor (%) – Region 1 (Glasgow)

E ESE SE SSE S SSW SW WSW W

63

60

58

55

51

48

73

72

70

68

66

-90

79

79

79

79

78

77

76

75

76

74

70

67

63

59

85

84

82

81

79

85

85

85

85

-67,5 -45 -22,2

79 79 79

81

83

84

83

86

88

84

87

90

90

91

92

93

93

95

97

98

93

92

91

90

88

86

83

80

76

72

67

92

89

86

82

78

73

98

98

97

96

94

94

91

88

84

80

75

99

99

98

97

96

22,5

79

84

87

91

93

96

97

98

95

92

89

85

80

75

100

100

100

98

97

0

79

84

88

91

94

96

98

99

89

87

84

80

76

72

95

95

94

93

91

45

79

83

86

89

91

93

94

95

81

79

76

73

70

66

88

87

86

85

83

67,5

79

82

84

85

86

87

88

88

70

68

65

63

60

57

78

76

75

74

72

90

79

80

80

80

80

80

79

79

Orientation

65

70

75

80

85

90

40

45

50

55

60

20

25

30

35

Pitch

0

5

10

15

Performance Factor (%) – Region 2 (Manchester)

E ESE SE SSE

78

77

76

75

-90 -67,5 -45 -22,2

80 80 80 80

80

79

79

82

83

84

83

86

88

84

88

91

85

86

86

85

90

92

92

93

93

95

97

98

76

73

70

66

62

58

85

84

82

80

78

63

60

57

54

51

47

73

72

70

68

65

93

92

91

90

88

85

82

79

75

70

66

91

88

85

81

76

71

98

98

97

96

94

S SSW SW WSW W

89

86

83

79

75

70

95

95

94

93

91

45

80

83

86

89

91

93

94

95

94

91

87

93

78

73

100

100

99

98

96

0

80

84

88

92

94

97

98

99

81

78

75

72

69

65

88

87

86

85

83

67,5

80

82

84

85

87

87

88

88

93

90

87

83

78

73

99

99

98

97

95

22,5

80

84

88

91

94

96

97

99

69

67

65

62

59

56

77

76

75

73

71

90

80

80

80

80

80

80

79

78

17

18

Orientation

65

70

75

80

45

50

55

60

85

90

Pitch

0

5

10

15

20

25

30

35

40

Performance Factor (%) – Region 3 (Cambridge)

E ESE SE SSE S SSW SW WSW W

64

61

59

56

72

70

69

66

53

49

77

76

75

74

-90 -67,5 -45 -22,2

79 79 79 79

79

79

79

798

81

83

84

85

83

86

88

90

84

87

91

93

86

86

86

85

92

93

93

93

95

97

98

98

84

83

81

79

77

74

71

67

63

59

93

92

90

88

86

83

80

76

71

67

92

89

85

81

98

97

96

94

76

71

93

90

87

83

99

98

97

95

78

73

96

97

98

99

22,5

79

84

88

91

94

94

91

87

83

100

99

98

96

79

73

97

98

99

100

0

79

84

88

91

94

88

86

82

79

94

93

92

90

74

70

92

94

94

95

45

79

83

86

89

91

80

78

75

72

86

85

84

82

68

64

87

87

87

87

67,5

79

82

83

85

86

69

67

64

62

75

74

72

71

59

56

79

79

78

77

90

79

80

80

80

80

Orientation

65

70

75

80

45

50

55

60

85

90

25

30

35

40

Pitch

0

5

10

15

20

Performance Factor (%) – Region 4 (Southampton)

E ESE SE SSE S SSW SW WSW W

63

60

57

54

71

69

67

65

51

48

77

76

74

73

-90 -67,5 -45 -22,2

80 80 80 80

80

79

79

78

82

83

84

85

83

86

89

90

84

88

91

94

86

86

85

84

92

93

93

93

96

97

98

98

83

82

80

78

75

73

69

66

62

57

92

91

89

87

85

82

78

74

70

64

91

88

84

80

98

97

95

93

75

69

92

89

85

81

99

98

96

94

76

71

96

98

98

99

22,5

80

84

88

91

94

93

90

86

82

100

99

98

96

77

71

97

99

100

100

0

80

85

89

92

95

87

84

81

77

94

93

92

90

73

68

93

94

94

94

45

80

84

87

89

91

79

77

74

70

86

85

83

81

67

63

87

87

87

87

67,5

80

82

84

85

86

68

65

63

60

75

73

72

70

57

55

79

78

77

76

90

80

80

80

80

80

Area Factor

Orientation

50

55

60

65

30

35

40

45

70

75

80

85

90

Pitch

0

5

10

15

20

25

Average area factor, all regions

E ESE SE SSE S SSW SW WSW W

-90 -67,5 -45 -22,2 0 22,5 45 67,5 90

1.49

1.49

1.49

1.49

1.49

1.49

1.49

1.49

1.49

1.49

1.43

1.39

1.36

1.35

1.36

1.38

1.42

1.49

1.51

1.38

1.31

1.26

1.25

1.26

1.30

1.37

1.48

1.52

1.35

1.25

1.19

1.17

1.18

1.23

1.32

1.48

1.54

1.33

1.20

1.13

1.58

1.31

1.17

1.09

1.11

1.06

1.12

1.08

1.18

1.14

1.29

1.27

1.48

1.50

1.61

1.31

1.15

1.06

1.03

1.05

1.12

1.26

1.52

1.66

1.32

1.14

1.04

1.01

1.03

1.11

1.26

1.55

1.72

1.34

1.14

1.04

1.00

1.02

1.10

1.27

1.58

1.79

1.37

1.15

1.04

1.00

1.02

1.11

1.28

1.63

1.88

1.41

1.17

1.05

1.01

1.03

1.13

1.31

1.68

1.97

1.46

1.21

1.08

1.03

1.06

1.15

1.35

1.75

2.10

1.53

1.26

1.12

1.07

1.09

1.19

1.40

1.83

2.24

1.62

1.32

1.17

1.12

1.14

1.25

1.46

1.92

2.41

1.73

1.40

1.24

1.18

1.20

1.32

1.55

2.03

2.63

1.87

1.51

1.33

1.27

1.29

1.40

1.66

2.17

2.89

2.05

1.65

1.45

1.38

1.40

1.52

1.79

2.33

3.21

2.28

1.83

1.61

1.53

1.55

1.67

1.96

2.52

3.62

2.58

2.08

1.83

1.73

1.74

1.87

2.17

2.76

In order to maximise the solar irradiation available when it is not possible to achieve due south orientation and 40° pitch, it is possible to increase the collector area to compensate for this. The following table shows the relevant average multiplication factor for the collector area.

In most cases, the variety of standard VELUX solar hot water systems are sufficient for the majority of design applications.

However, should you wish to design a bespoke system please contact VELUX solar energy.

Energy efficient, cost effective

We have completed three case studies which give an indication of the likely value of the energy savings that can be achieved by the installation of a VELUX solar hot water system. For the purposes of these case studies, we have assumed that the auxiliary boiler is gas fired in all cases.

Case study 1

This case study evaluates three collectors with a combined area of 7.5m

2 and a 375 litre tank, typically specified for households of between four to seven occupants.

Region 1

Glasgow

Region 2

Manchester

Region 3

Cambridge

Region 4

Southampton

3 x collectors at 7.5m

2 with 375 litre tank

Number of people

Daily draw-off

Net hot water load, kWh/year

Solar fraction, %

Auxiliary energy input needed, kWh/year

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

4

160

3051

59.6

1574

2978

3351

3829

5

200

3814

54.9

2070

3275

3684

4211

Solar fraction, %

Auxiliary energy input needed, kWh/year

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

64.2

1417

3153

3547

4054

59.5

1878

3488

3924

4485

Solar fraction, %

Auxiliary energy input needed, kWh/year

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

Solar fraction, %

Auxiliary energy input needed, kWh/year

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

73.1

1090

3516

3956

4521

68.1

1256

3332

3748

4284

68.0

1514

3893

4379

5005

63.0

1711

3674

4133

4724

6

240

4577

50.8

2608

3525

3966

4532

55.3

2386

3772

4243

4849

63.3

1962

4243

4773

5455

58.5

2214

3963

4458

5095

7

280

5340

47.1

3187

3730

4196

4795

51.6

2929

4016

4518

5164

59.8

2459

4538

5106

5835

54.4

2754

4211

4737

5414

Summary:

The solar fraction that can be gained increases from a significant 59% in region 1 to a maximum of 73% in region 4. The solar benefit that can be achieved with a 70% efficient boiler within region 4 is 5835 kWh/year.

19

20

Case study 2

The following table displays the results of a solar hot water system designed for a household of three to five people, with a 280 litre tank, and two collectors that give a combined area of 5m

2

.

Region 1

Glasgow

Region 2

Manchester

Region 3

Cambridge

Region 4

Southampton

Number of people

Daily draw-off

2 x collectors at 5m

2 with 280 litre tank

3

120

Net hot water load, kWh/year

Solar fraction, %

Auxiliary energy input needed, kWh/year

2287

54.4

1370

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

2123

2388

2729

Solar fraction, %

Auxiliary energy input needed, kWh/year

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

59.1

1245

2262

2544

2908

Solar fraction, %

Auxiliary energy input needed, kWh/year

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

Solar fraction, %

Auxiliary energy input needed, kWh/year

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

67.8

1005

2528

2844

3251

62.3

1144

2374

2671

3052

61.3

1467

2864

3222

3682

55.9

1642

2669

3003

3432

4

160

3051

48.7

1900

2383

2681

3064

53.2

1745

2555

2874

3285

55.8

1985

3136

3528

4032

50.5

2194

2904

3267

3734

5

200

3814

43.9

2475

2592

2916

3332

48.1

2303

2783

3131

3578

Summary:

In region 4 a valuable solar fraction of up to 67% can be gained. In addition, when combined with a 70% efficient boiler a productive solar benefit of 4032 kWh/year can be achieved.

Case study 3

This case study looks at a typical solar hot water system designed to suit two to three people, using a 180 litre hot water storage tank, with one 2.5m

2 collector.

Region 1

Glasgow

Region 2

Manchester

Region 3

Cambridge

Region 4

Southampton

Number of people

Daily draw-off

1 x collector at 2.5m

2 with 180 litre tank

2

80

Net hot water load, kWh/year

Solar fraction, %

Auxiliary energy input needed, kWh/year

1526

40.9

1247

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

1152

1297

1482

Solar fraction, %

Auxiliary energy input needed, kWh/year

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

45.1

1168

1240

1395

1595

Solar fraction, %

Auxiliary energy input needed, kWh/year

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

Solar fraction, %

Auxiliary energy input needed, kWh/year

Solar benefit with a 90% efficient boiler, kWh/year

Solar benefit with an 80% efficient boiler, kWh/year

Solar benefit with a 70% efficient boiler, kWh/year

52.2

1035

1388

1562

1785

46.6

1138

1274

1433

1637

44.3

1593

1614

1815

2075

39.4

1716

1477

1662

1899

3

120

2287

34.5

1845

1334

1500

1715

38.0

1754

1435

1614

1845

Summary:

This combination can create an advantageous solar benefit of up to 2075 kWh/year when combined with a 70% efficient boiler.

The maximum solar fraction created supplies a productive 52.2%.

21

22

Optional extras

VELUX solar hot water systems can also be supplied with a number of optional extras, this will allow you flexibility to meet any unique requirements of your development. Please contact your authorised

VELUX merchant if you wish to place an order for any of the items detailed below.

Flexible flow and return pipes

Immersion heater

Filling pump

The standard package provides these in 10m lengths, however as optional extras you can purchase them in additional lengths of 15m and 20m. Arriving preinsulated, they are capable of handling temperatures ranging from +175°C down to -40°C.

An immersion heater is an electrical element that heats up the water in the tank. If you do not have the benefit of a gas or solid fuel boiler you can install an immersion heater into the tank for your auxiliary hot water. It can also be used as back up heating for your water.

Highest standards guaranteed

As it is manufactured to such a high standard, the VELUX solar thermal system is covered by an exceptional manufacturer’s guarantee.

The solar hot water tank is guaranteed for 10 years from the date of manufacturing, provided the protective magnesium anode has been tested regularly.

All accessories and components are guaranteed for 3 years.

VELUX solar collectors and flashings are guaranteed to comply with the standard industry home warranty of 10 years.

System servicing

Servicing should only be carried out by a competent installer in the installation and maintenance of unvented/vented solar water systems.

• Any spare parts used during a service must be authorised VELUX parts.

• Always disconnect the electrical supply before removing any electrical equipment covers.

• Never bypass any thermal controls or operate system without the necessary safety valves.

Water contained in the VELUX solar hot water system may be very hot, especially following a thermal control failure. Caution must be taken when drawing water from the unit.

VELUX recommend using a motorised pump when filling the solar circuit to ensure that all air pockets are removed. The filling pump has the capacity to hold

50 litres of fluid. The filling pump station has a large opening for pouring and mixing the solar fluid and it comes with two connecting hoses. The strong pump with high flow ensures trouble free filling and pressurising. To help with storage and ease of transport, it is supplied on a wheeled frame.

23

VELUX Company Ltd

Kettering Parkway,

Kettering, Northants,

NN15 6XR

01536 510020 Telephone

01536 510411 Fax [email protected]

www.carbon-neutralhome.co.uk

Unit 1, Willsborough Cluster

Willsborough Industrial Estate,

Clonshaugh, Dublin 17

01 816 1616 Telephone

01 848 8787 Fax [email protected]

www.carbon-neutralhome.ie

Woodside Way,

Glenrothes

Fife, Scotland

KY7 4ND

01592 778225 Telephone

01592 776980 Fax [email protected]

www.carbon-neutralhome.co.uk

© 2006 VELUX GROUP ® VELUX, VELUX logo are registered trademarks.

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