Roofing Modular Training Unit 3 Sustainable Roofing Solutions Tutor Notes

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1 Roofing Modular Training Unit 3 Sustainable Roofing Solutions Tutor Notes This session covers basic principles of sustainability and why things need to change. Duration: minutes Contents of this training pack 1 Attendance List 2 Tutor Notes 3 PowerPoint Presentation 4 End Test & Answer Sheet 5 Student Handout Tutor directions are shown in red. What the Learner Sees A Roofer s Guide to Sustainability Sustainable Roofing Solutions YIRTG is pleased to acknowledge that the Roofers Guide to Sustainability Modular Programme was developed as a result of funding provided by CITB ConstructionSkills as part of their long term commitment to training and quality standards in the specialist roofing sector. This support is gratefully appreciated What the Presenter says/does This session forms part of a series which has been developed for roofing companies with funding from CITB ConstructionSkills to raise awareness of environmental issues and the challenges and opportunities this provides for businesses The Plan Sign attendance Register Complete Activity Aims Presentation Activity Review First we must complete the formalities everyone should sign the attendance list. The first thing we will do is Think of as many sustainable roof products as possible Use a flipchart to take down the products raised by the group Course Aims To provide an overview of solar products To explain the types of Green roofs and their benefit to the environment We will first have a look at an overview of solar products available Then we will look at the Green roofs currently available.

2 Solar We are now going to look the solar technologies currently available Let s first see what we already know Activity How many types of Solar Products can you name? How many types of solar products do we know Make a list on a flip chart or ask learners to work in small groups to discuss they make give a list of products or types of solar both are considered in the following slides Photovoltaic The term "photovoltaic" comes from the Greek meaning "light", and from "Volt The Term Photovoltaic comes from the greek meaning for light and from volt, the unit of electro-motive force, the volt, in turn comes from the last name of the Italian physicist Alessandro Volta, inventor of the battery (electrochemical cell). The term "photo-voltaic" has been in use in English since 1849 How a crystalline PV cell is produced Silica sand. Silica is heated in a furnace The silicon is then with carbon to produce further treated to silicon % purity. To create solar-grade silicon it is converted into an intermediate silicon-rich gas and then blown over seeds of pure silicon at high temperatures. Theses seeds are often rods, which grow as the silicon is deposited on them. The purified silicon is then made into ingots. The ingots are sliced into wafers microns thick. How a crystalline PV cell is produced You may recognise these as parts of the panels you see The sliced wafers are doped to create a positive and a negative sided cell. The cell is then cut as square as possible and thin metallic contacts printed on both sides. Several cells are connected together and laminated between glass and a rear substrate to create a solar panel.

3 Types of crystalline PV cells There are two types of wafer photovoltaic cells: Monocrystalline this is the most effective of current PV technologies Monocrystalline: Single cylindrical crystal ingot, drawn from a bath of liquid silicon. The ingot is trimmed to produce a nearly square cross section, prior to being cut into wafers. In good light conditions, monocrystalline is the most efficient of all current PV technologies. Types of crystalline PV cells Polycrystalline: Offcuts and breakages are recovered from other parts of the production process. These are recycled by melting, and cooling them into a block. This is then cut into wafers, and since it is rectangular in section, there is no futher wastage. Polycrystalline cells are typically less efficient than monocrystalline ones. Due to polycrystalline cells being truly square though, they can be cut without any wasted material. This means that modules produced from both cell types tend to have similar power yields. Polycrystalline made from offcuts but a more efficient shape Amorphous Thin Film Thin Film is produced when amorphous silicon is deposited on a backing substrate Tis reduces the amount of silicon required to make the cells and reduces the cost of thin film technology compared to alternatives Thin film is a good alternative where weight restrictions limit the use of other technologies or as a cheaper alternative for a larger area. Thin film is attached to a backing membrane and most often used for large scale roofs These technologies all provide electricity On-Roof Photovoltaic On Roof Panels are fixed over existing roof tiles In-Roof Photovoltaic In roof systems replace the tiles and are more common in new build All forms of PV attract subsidies through the Feed In Tariff (FIT) There has been much talk about the levels of Feed in Tariff being reduced but many would still say it gives a good return on investment. The feed in tariff pays for all the energy produced by the panels whether it is used in the producing property or passed to the national grid (Generation Tariff) and a further payment is made for the exported energy (Export Tariff). The property user also get the benefit of free electricity so this is a 3 way win.

4 Photovoltaic Tiles Photovoltaic tiles are the same size and shape as tiles used on more traditional roofs. Photovoltaic tiles are improving the look of solar and are less obvious New technologies make photovoltaics look like slates and tiles, more acceptable in some conservation areas. Low Ballasted Systems Low Ballasted Systems are an easy-to-install system. With a slope of 15 or 25 it is perfect for use on roofs with minimal load-bearing capacity and decreases both spot and distributed loads. With its aerodynamic design, the aluminium, stainless steel and galvanised steel mounting system adds a additional load of approx. 10 kg/m² to the roof plus the required ballast (depending on the location). Thin Film Welded Systems As a result of the advance in technology, thin films made of amorphous cells now offer the possibility to install modules over large roof areas. They are lightweight and flexible, so they can be integrated into most roof structures, while maintaining the main goal, i.e. generate optimal energy input. The importance of PV in architecture is also growing. As a result of the advance in technology, thin films made of amorphous cells now offer the possibility to install modules over large roof areas. They are lightweight and flexible, so they can be integrated into most roof structures, while maintaining the main goal, i.e. generate optimal energy input. Solar Thermal PROVIDING HOT WATER Solar Thermal panels usually fit on top of the roof and provide hot water only to the property. The Renewable Heat Incentive (RHI) are planning to funding for Solar Thermal from early 2013

5 Transpired Solar Collectors PROVIDING HEATING Transpired solar collectors are installed as an additional micro perforated pre-finished steel skin onto an existing (or new) structurally sound wall (metal and non metal), creating a cavity between the wall and the metal skin. The pre-finished steel has enhanced thermal absorption properties and absorbs the sun s radiant energy, subsequently heating the boundary layer of air to the exposed side of the metal skin. Negative air pressure created within the cavity by a ventilation fan draws ambient outside air through the micro perforations in the transpired solar collector s surface. This outside air is then heated as it passes through the perforations and collected within the cavity. Fresh heated air from the cavity is then fed either directly into the building as ventilation air (industrial applications), or ducted into a HVAC unit (commercial & residential applications), where it is used as a preheater to the main heating system. A transpired solar collector can collect around 50% of the energy falling on its surface which equates to approximately 500wp/m2 of the collector s surface area and can deliver around 250 KWH/M2 per year or up to 50% of space heating requirements depending on building configuration and usage. CA Solarwall Case study shows potential savings of this technology CA is the name of the company who manufacture the Solarwall Rainscreen / Overcladding Rainscreen and overcladding One of the ways in which rainscreen can benefit existing buildings is overcladding. Older buildings may well require remedial and aesthetic work to make them suitable for today s environment. In addition, thermal efficiencies inherent in older building stock will almost certainly need radically upgrading to meet today s exacting regulations. Key features for overcladding include: - Restoration of existing façade - Extending the life of the building - Improving appearance & image - Provide thermal insulation & weather-tightness

6 - Improve acoustical performance of the building - Lower maintenance cost Adding insulation to the external surface of the loadbearing structure has three key benefits: - Increased thermal efficiency dependent on the fixing system used - No loss of internal space - Lightweight and easy to fix Lets consider the less positive aspects change in verge and eaves details may be required down pipes will have to be removed drainage gullies at the foot of gutters may have to be moved details around windows may be difficult. Do we really want to lose our historic building materials? There is a place for cladding but possibly not a extensively as some believe and not at the cost of our heritage. We will now look at Green Roofs Green Benefits of Green Roofs Reduced rainwater run-off Extended life of roof covering Habitat conservation Building insulation and Reduced sound transfe Green roofs are installed on roofs over standard waterproofing covering. The vegetation or 'green' element is built up from layers including a drainage layer, barrier membrane, growing medium and plants Intensive Green Roofs A landscape which can include a wide variety of vegetation, varying from lawn grass to large trees, usually including a significant element of hard landscape, and which requires a high degree of regular maintenance to control the vegetation and keep it flourishing

7 Extensive Green Roofs The cultivation of plants which are wind, frost, & drought resistant, which require very little maintenance and are self propagating. The bulk of this type of vegetation will consist of mosses, succulents (sedums), herbaceous plants and grasses Brown Roofs The creation of a landscape designed to replace that which has been lost beneath the footprint of the building, so as to attract and retain the wild life which would otherwise have been lost. Activity The KnowledgeTest should be circulated and time allowed for completion. The papers can should be marked by the learners and discussion of answers can follow if there is time. KnowledgeTest Check your knowledge The Yorkshire Independent Roof Training Group is pleased to acknowledge that the Roofers Guide to Sustainability is delivered as a result of funding provided by CITB ConstructionSkills as part of their long term commitment to training and quality standards in the specialist roofing sector. Just a word of thanks again to ConstructionSkills for funding the preparation of these materials This support is gratefully appreciated