Beautifully Integrated Solar
PV48 Cl/SfB (47) Ng2 May 2013
PV48 Beautifully Integrated Solar
In 2008 the UK government introduced the Climate Change Act. This commits the UK to reducing carbon emissions by 80% by 2050. Also, the EU Renewable Energy Directive commits the UK to increase its proportion of power produced from renewable sources to 15% by 2020. To help ensure we meet these targets the Government has introduced two main drivers; firstly, legal obligations through the Building Regulations and the Code for Sustainable Homes. Secondly, financial incentives to encourage the installation of local renewable energy sources.
Building Regulations and the Code for Sustainable Homes A series of step changes to Building Regulations are planned to lead to the building of zero carbon homes by 2016. Each step change requires measures such as increased insulation, better airtightness, greater efficiency in energy use and eventually, sufficient onsite micro generation to fully offset the home’s energy usage from heating, ventilation, hot water, fixed lighting and building services.
Feed-in Tariff (FIT) The Feed-In Tariff (FIT), also referred to as ‘Clean Energy Cashback’, is a Government backed scheme designed to pay homeowners for creating their own “green electricity”. It was introduced in April 2010 to encourage the take up of renewable energy to help fulfil the UK’s target of 15% of total energy from renewables by 2020; this is from a starting point of just 2% in 2009. The tariff gives three financial benefits; firstly, and the most financially attractive, payment is made for all the electricity produced, even if the homeowner uses it. Additionally, a smaller payment is made for electricity exported into the national grid. Thirdly the electricity bill is reduced because the energy produced by the panels reduces the amount drawn from the grid. Tariff levels vary depending on the size of the system but they can be claimed by everyone, including households, landlords, businesses and organisations such as schools and care homes. To be eligible to claim the tariff the solar electrical system commissioned by an MCS accredited contractor. The installer will provide the necessary certification to the property owner, who can forward this in their tariff application to their energy provider.
On cover: Sandtoft’s PV48 solar system integrated with Humber clay plain tiles. On this page: Sandtoft’s PV48 solar system integrated with Humber clay plain tiles. 3
PV48 The Art of Solar Sandtoftâ€™s PV48 solar system integrated with fibre cement slates.
Versatile Solar solutions for UK roofs In order to help meet renewables targets Sandtoft has launched PV48, a new roof-integrated photovoltaic solar system, designed for use on pitched roofs with easy-to-fit flashings that enable it to integrate with virtually all types of slate or tile. It can be used on both existing and new build properties and installed by any trained roofing contractor. Each PV48 panel covers 1.4 square metres on the roof, giving considerably more power output per square metre than many in-line systems. Because we believe that the roofing contractor is the best person to be on the roof, PV48 is expressly designed for installation by the roofer, using techniques that he is already familiar with, thus reducing the risk of poor workmanship and subsequent weatherproofing problems.
PV48 is aesthetically pleasing; both the panels and the flashings are black. The flashings provide seamless integration between the roof tiles and solar panels as well as maintaining straight vertical lines on the roof, avoiding the step effect that occurs with in-line broken bonded PV systems. Sandtoft PV48 is MCS certified and registered on the MCS website list of suitable PV products. The website also provides lists of MCS accredited installers.
Microgeneration Certification Scheme (MCS) The Microgeneration Certification Scheme (MCS) is an independent scheme supported by the Department of Energy and Climate Change, for the certification of microgeneration products and installers. The scheme is designed to create safe, reliable and low carbon energy sources to meet EU 2020 renewables targets. Its aim is to provide standards for unfamiliar technologies, protect consumers and to offer information through the certification “mark”.
Sandtoft’s PV48 solar system integrated with Old English clay pantiles.
To be eligible to claim the feed-in tariff both the PV system and the electrical commissioning contractor must be MCS certificated. 5
PV48 Innovative Design Sandtoftâ€™s PV48 solar system integrated with natural slate.
Roof performance The Sandtoft PV48 solar system has been designed by roofing experts to integrate into most slate and tile roof coverings. The system has been designed in the UK and has been rigorously wind tunnel tested to ensure it is extremely resistant to UK weather conditions. The system is integrated with the roof tiles or slates, rather than installed over the top of the roof covering, so it does not increase the roof weight loading. On new build or re-roof projects, it saves the cost of the roof tiles it replaces. Because the PV48 integrates with the tiling there are no brackets or cables penetrating the roof covering, further reducing the risk of water ingress.
Solar roofs generate electricity from daylight; intense sunlight is not necessary. The UK is a perfectly suitable location for solar roof power generation. UK irradiance levels currently stand at 1000 W/m2/year for London, with a range of 800 W/m2/ year to 1000 W/m2/year across the UK; similar in fact to irradiance levels in Germany and the Netherlands.
1. Roof installation area Ideally a south facing roof at a pitch of between 20 and 50 degrees from horizontal and with no shading from roof projections, aerials, satellite dishes, trees or other buildings etc. 2. PV48 solar electric roof panels The panels integrate into the roof and generate electricity from daylight. 3. Inverter The solar array connects to the inverter which converts the DC electric from the array into usable grid-level AC electric. 4. Grid supply and generation meter The inverter is connected to the consumer unit and feeds the electricity from the solar array into the house supply. 5. Electricity demand During the day solar electricity is used in preference to grid electric. Any excess electricity is fed into the grid and sold to the electricity company. Electricity is drawn from the grid at night and when demand exceeds the solar systemâ€™s output.
How the system works Solar PV is a simple renewable energy system where cells are used to convert sunlight into electricity. These cells consist of thin layers of semi-conducting material silicon which generates an electrical charge when exposed to daylight. The greater the intensity of the light the greater the flow of electricity.
Guarantees All the on roof components; ie solar panels, flashings and fixings etc, are guaranteed for 15 years. In addition, Sandtoft can provide a comprehensive RoofSpec design specification which will further guarantee that the whole roof, including the PV48 system, will remain durable and weathertight for at least 15 years. The power output of the PV48 system is guaranteed to be not less than 80% of its original performance after 25 years.
Planning permission and Building Control In normal circumstances Planning Permission is not needed to install a Sandtoft PV48 system on the roof. However, if the building is listed, or is in a conservation area or has had its â€˜permitted developmentâ€™ rights removed then the local planning authority must be consulted before installing solar panels as conditions may be imposed. For example, the planning authority may ask for the PV system to be positioned on a roof face which is not visible from the main road or perhaps on an outbuilding if possible.
PV48 Technical Data
Roof installation Suitable for new build and retrofit, installation can be carried out by the roofing contractor with minimal training, which Sandtoft can provide. All roof components, including flashings are supplied with the solar panels as a complete system.
The system is simply installed over the tile battens using standard counterbattens without the need to reset the tile gauge.
The roofing contractor connects the solar panels together with simple push fit connectors and passes a pair of cables through the underlay into the roof space for later connection by the electrical contractor.
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Example: a roof that faces south-west and has a pitch of 45° still yields 90% of the maximum potential power output
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Sandtoft’s PV48 solar system integrated with Calderdale concrete tiles.
Electrical data per panel measured under STC (Standard test conditions: 1000W/m2, 25ºC, AM 1.5)
Power per panel Max. power voltage Open circuit voltage Max. power current Short-circuit current Panel data Number of cells Maximum system voltage Reverse current loading capacity Front surface Panel Frame
200 W 25.0 V 30.25 V 8.0 A 8.7 A
Once the on roof installation has been completed and the building is connected to the power grid, the solar electrical system can be installed and commissioned by an MCS certified installer.
On-roof data Size of panel 1394 w mm x 1023 h mm Installed coverage of panel 1377 w mm x 991 h mm Minimum roof pitch 22.5º Weight per panel 17 kg Weight as laid 12.2 kg/m2 External fire test (BS 476-3: 2004) unclassified
Electrical connection and commissioning An electrical pack is supplied with every PV48 system which includes the appropriate inverter, total generation meter, isolators and DC cables.
Note: Remember to include flashings when calculating the dimensions of the array.
Popular system sizes 48 1000 V 17 A special hardened low iron glass connection box with 3 bypass diodes and 2.0m solar cable aluminium frame and flashing system in matt black making for greater fire resistance and long term durability
System size (panels)
Output per year (kWh)
System size (kWp)
Carbon offset per year (kg)
% of typical home’s electricity requirements per year*
*based on a typical electricity consumption of 3,300kWh/year: source www.ofgem.gov.uk
Maintenance PV systems need little maintenance. Panels should be cleaned periodically for best performance, although the rain washes them naturally. 9
PV48 Green Credentials Sandtoftâ€™s PV48 solar system integrated with concrete Plain Tiles.
Environmental innovation At Sandtoft, we are committed to achieving environmental excellence and to reducing the environmental impact of our operations. We are driven, not only by legislation changes which we always better, but by the belief that we have a responsibility to act decisively to protect our environment for future generations. Here are some of the key areas in which we think we are making a difference: 100% Green Electricity At the end of October 2006, Sandtoft switched over to a 100% green source of electricity for all UK operations. Each production facility and office is powered by electricity generated from wind farms and hydro-electric plants. This investment has cut our CO2 emissions by 25% per annum. Building Integrated Photovoltaics In addition, the installation of an 18 panel, 3.4 kWp PV48 solar system on the Sandtoft office roof in Doncaster has reduced our consumption of Green electricity from the national grid, freeing up this zero carbon resource for others.
Climate Change Targets As part of the ceramic industryâ€™s Climate Change Agreement with the UK government, Sandtoft has committed to achieving a 10% reduction in CO2 emissions per tonne of clay product over 10 years. We have already beaten our 10 year target, with CO2 reduced now by 16.5%.
Sandtoftâ€™s PV48 solar system integrated with Cassius slate.
Using Recycled Materials Sandtoft has been using recycled aggregates in the production process since the 1990s. Our recycled slates are manufactured with 80% recycled slate waste recovered from UK quarries where high levels of waste have accumulated over the years. More recently we have introduced recycled material to our concrete tile range. Starting from an initial figure of approximately 10% recycled content in 2006, we have now invested in facilities to provide up to 20% recycled material across all our concrete tile range.
Waste Minimisation Sandtoft sends very little waste to landfill and aims to reduce that to zero (non hazardous waste). Currently the majority of waste is either recycled back into the manufacturing process or collected for off-site recycling. Environmental Management All Sandtoft UK sites are certified to Environmental Management System ISO 14001.
On back cover: Sandtoftâ€™s PV48 solar system integrated with concrete Plain Tiles.
Designing energy efficient products We are also working hard to reduce the weight of a roof, as this can lead to savings in the CO2 released through manufacturing and transportation to site. In manufacturing clay tiles, the number of KWh of electricity and gas used, and the CO2 emissions which accompany this energy usage, are proportional to the tonnage of clay extracted, processed, dried and fired. Less tonnage also means that more roofs can be delivered on one lorry. On that basis the Sandtoft product that shows greatest savings is the 20/20 interlocking clay plain tile. Due to its innovative, interlocking, lightweight design, specifying the 20/20 over traditional clay plain tiles will reduce the CO2 emissions by 36% per roof. When the additional benefit of our green electricity is taken into account, this figure increases to over 50%. 11
Sandtoft Roof Tiles Ltd Belton Road Sandtoft Doncaster DN8 5SY T 0844 9395 900 F 0844 9395 950 email@example.com www.sandtoft.com www.weinerberger.co.uk Tile colours shown in this brochure are as accurate as the printing process will allow. At Sandtoft we are continually innovating and improving our product range. We reserve the right to change product specifications without notice. This brochure is printed on FSC certified paper manufactured with an 100% recycled fibre content.