Embodied Energy

By: Jindal Ritesh Kailash

09AR1026

Guided by:

Prof. Dr. Abraham George

Embodied Energy:

The embodied energy (carbon) of a building material can be taken as the total primary energy consumed (carbon released over its life cycle). This lifecycle includes raw material extraction, transport, manufacture, assembly, installation, disassembly, deconstruction and/or decomposition.

Ideally the boundaries would be set from the extraction of raw materials (including fuels) until the end of the products lifetime (including energy from manufacturing, transport, energy to manufacture capital equipment, heating and lighting of factory, maintenance, disposal etc.), known as ‘Cradle-to-Grave’. It has become common practice to specify the embodied energy as ‘Cradle-to-Gate’, which includes all energy (in primary form) until the product leaves the factory gate. The final boundary condition is ‘Cradle –to-Site’, which includes all of the energy consumed until the product has reached the point of use (ie the building site).

Different methodologies produce different understandings of the scale and scope of application and the type of energy embodied. Some methodologies account for the energy embodied in terms of the oil that supports economic processes.

The Embodied energy of few materials are given below:-

Material Energy MJ/kg

Carbonkg CO2/kg

Densitykg /m3

Aggregate 0.1 0.005 2240

Concrete (1:1.5:3 eg in-situ floor slabs, structure) 1.11 0.159 2400

Concrete (eg in-situ floor slabs) with 25% PFA RC40

0.97 0.132  

Concrete (eg in-situ floor slabs) with 50% GGBS RC40

0.88 0.101  

Bricks (facing) 8.2 0.52 1700

Bricks (common) 3.0 0.22 1700

Concrete block (150mm medium weight) 0.71 0.08 1900

Aerated block 3.50 0.30 750

Rammed earth 0.45 0.023 1460

Limestone block 0.85   2180

Marble 2.00 0.112 2500

Cement mortar (1:3) 1.40 0.213  

Steel (virgin) 35.30 2.75 7800

Steel (recycled) 9.50 0.43 7800

Steel (typical virgin/recycled) 24.40 1.77 7800

Timber (general) 8.50 0.46 480 - 720

Glue laminated timber 12.00 0.65  

Sawn hardwood 7.40 0.47 700 - 800

Cellular glass insulation 27.00    

Cellulose insulation (loose fill) 0.94 – 3.3   43

Cork insulation 26.00*   160

Glass fibre insulation (quilt) 28.00 1.35 12

Flax insulation 39.50 1.70 30*

Rockwool (slab) 16.80 1.05 24

Polystyrene insulation 88.60 2.50 15 – 30*

Polyurethane insulation 72.10 3.00 30

Woodwool board insulation 20.00 0.98  

Wool (recycled) insulation 20.9   25*

Straw bale 0.24 0.01 100 – 110*

Mineral fibre roofing tile 37 2.70 1850*

Slate (UK – imported) 0.1 – 1.0 0.006 – 0.056

1600

Clay tile 6.50 0.46 1900

Concrete tile 2.0 0.215 2100

Aluminium (general & incl 33% recycled) 155 8.24 2700

Bitumen (general) 47 0.48  

Hardboard 16.00 0.86 600 - 1000

MDF 11.00 0.59 680 – 760*

OSB 9.50 0.51 640*

Plywood 15.00 0.81 540  - 700

Plasterboard 6.75 0.38 800

Gypsum plaster 1.80 0.12 1120

Glass 15.00 0.85 2500

PVC flooring 65.64 2.29 1200

PVC composite tiles 13.70   1600*

Linoleum 25.00 1.21 1200

Terrazzo tiles 1.40 0.12  

Ceramic tiles 9.00 0.59 2000

Nylon carpet 67.90 - 149

3.55 – 7.31

 

Wool carpet 106.00 5.48  

Wallpaper 36.40 1.93  

Wood stain / varnish 50.00    

Concrete paving 1.24 0.127 2000*

Asphalt paving 2.41 0.14 2100

Vitrified clay pipe (DN 500) 7.86 0.53  

Iron (general & average) 25 1.91 7870

PVC pipe 67.5 2.5  

Copper (average incl. 46% recycled) 48 3.01 8600

Lead (incl 61% recycled) 25 1.33 11340

Ceramic sanitary ware 29.00 1.48  

Windows

Material Energy MJ/m2

Carbonkg CO2/m2

Aluminium 2x glazed, argon filled, window 5470 279

PVC 2x glazed, argon filled, window 2310 118

Aluminium clad timber, 2x glazed, argon filled, window 1200 61

Timber 2x glazed, argon filled, window 360 18

Paint

Material Energy MJ/m2

Carbonkg CO2/m2

Paint (2 coats) 20.4 1.06

Photovoltaic (PV) cells

Material Energy MJ/m2

Carbonkg CO2/m2

Monocrystalline (average) 4750 242

Polycrystalline (average) 4070 208

Thin film (average) 1305 67

Key: * - figures by GreenSpec obtained from publicly available information

Embodied energy methodologies

Embodied energy analysis is interested in what energy goes to supporting a consumer, and so all energy depreciation is assigned to the final demand of consumer. Different methodologies use different scales of data to calculate energy embodied in products and services of nature and human civilization. International consensus on the appropriateness of data scales and methodologies is pending. This difficulty can give a wide range in embodied energy values for any given material. In the absence of a comprehensive global embodied energy public dynamic database, embodied energy calculations may omit important data on, for example, the rural road/highway construction and maintenance needed to move a product, human marketing, advertising, catering services, non-human services and the like. Such omissions can be a source of significant methodological error in embodied energy estimations. Without an estimation and declaration of the embodied energy error, it is difficult to calibrate the sustainability index, and so the value of any given material, process or service to environmental and human economic processes.

Standards:

The UK Code for Sustainable Homes and USA LEED Leadership in Energy and Environmental Design are standards in which the embodied energy of a product or material is rated, along with other factors, to assess a building's environmental impact. Embodied energy is a new concept for which scientists have not yet agreed absolute universal values because there are many variables to take into account, but most agree that products can be compared to each other to see which has more and which has less embodied energy. Comparative lists (for an example, see the Bath University Embodied Energy & Carbon Material Inventory) contain average absolute values, and explain the factors which have been taken into account when compiling the lists.

Typical embodied energy units used are MJ/kg (mega joules of energy needed to make a kilogram of product), tCO2 (tonnes of carbon dioxide created by the energy needed to make a kilogram of product). Converting MJ to tCO2 is not straightforward because different types of energy (oil, wind, solar, nuclear and so on) emit different amounts of carbon dioxide, so the actual amount of carbon dioxide emitted when a product is made will be dependent on the type of energy used in the manufacturing process. For example, the Australian Government gives a global average of 0.098 tCO2 = 1 GJ. This is the same as 1 MJ = 0.098 kgCO2 = 98 gCO2 or 1 kgCO2 = 10.204 MJ.

Safety Factors to be taken:

In order to sustain the construction activity in future, it becomes inevitable to explore the following possibilities:

Use of energy-efficient alternative building technologies Efficient utilization of natural resources/raw materials Optimal designs and planning practices Recycling of building wastes Utilization of industrial/mine wastes for the manufacture of building materials Adopting energy-efficient process in manufacturing processes of building materials Use of renewable energy sources and technologies

Two Materials Chosen:

i. Tilesii. SMB (Stabilised Mud Blocks)

Tiles:

A tile is a manufactured piece of hard-wearing material such as ceramic, stone, metal, or even glass. Tiles are generally used for covering roofs, floors, and walls, showers, or other objects such as tabletops. Alternatively, tile can sometimes refer to similar units made from lightweight materials such as perlite, wood, and mineral wool, typically used for wall and ceiling applications. Less precisely, the modern term can refer to any sort of construction tile or similar object, such as rectangular counters used in playing games (see tile-based game). The word is derived from the French word tuile, which is, in turn, from the Latin word tegula, meaning a roof tile composed of baked clay.

Tiles are often used to form wall and floor coverings, and can range from simple square tiles to complex mosaics. Tiles are most often made from ceramic, with a hard glaze finish, but other materials are also commonly used, such as glass, marble, granite, slate, and reformed ceramic slurry, which is cast in a muld and fired.

Material Selection Tips Pros Cons Recommended Uses

Ceramic & Porcelain TileMade from clay, a natural and readily available (though finite) resource. Durable, low maintenance.

Look for locally manufactured tiles with high recycled content (glass, ceramic), preferably post-consumer. Avoid lead-based and radioactive glazes on some imported tiles.

Porcelain is typically harder, less porous (more impervious) and more scratch-resistant than ceramic.

* durable 

* easy to clean 

* resistant to stains and burning

* somewhat high embodied energy (for manufacturing)

* clay mining impacts land and water quality

* floor * countertop * wall * fireplace

Glass TileDurable material, often with recycled content.

Look for locally manufactured tiles with high recycled glass content, preferably post-consumer.

* sintering process used by some manufacturers requires less energy than conventional melting 

* up to 100% recycled content 

* durable 

* easy to clean

* resistant to stains and burning

* high embodied energy to fire and produce tiles 

* smooth tile surfaces will scratch under heavy wear

* floor * countertop / backsplash * wall * fireplace

Ceramic & Cement tiles:

Simply defined, ceramic tile is tile made of clay. What is cement tile? Well you get the picture. Ceramic and cement based tile are similar in at least one respect, they both are

often formed by similar means. That is where the similarity ends. After the formation of the tile body, ceramic tiles go through a firing process. Cement tiles are not fired.

All tiles start out in the earth. Raw materials are quarried and refined. In the case of ceramic tiles, this includes clays, talc, and other minerals. Obviously cement based tile include cements and sands. Great care is taken in the proper mixture of these materials, as each one is critical to the success, quality and characteristics of the product produced. Once the raw materials are quarried, prepared, and properly mixed, the tiles may now be formed.

After the tiles are formed, they must be hardened. Generally this is where the cement tile manufacturing process separates from the ceramic. In the case of cement tiles, they harden through a process called hydration. The cement simply hardens. This includes whatever glaze the manufacturer chooses to use. In the case of ceramic tiles, they are fired in a kiln under very high (2000 degrees F.) heat to harden the tile body and to create the surface glaze, if any.

When ceramic tiles are formed, their moisture content can vary plus or minus 6%. Since moisture is the tile manufacturer’s enemy during the firing process, the tiles must be dried to within 1% prior to kiln firing. If the moisture content were not brought down to this level, the tiles would explode as the moisture within the tiles boiled and became pressurized gas. The drying process can be accomplished in ovens or in the open air. Once the drying process is accomplished, the tiles can be placed or moved through a kiln.

When the body of the tile does not possess the color desired through and through, as in the case of certain ceramic mosaic or quarry tiles, the use of an engobe is necessary. engobe is applied just prior to the glaze and imparts color or opacity to the tile body. The quality of the engobe is of paramount importance as it can prevent stains from reaching the visual surface of the tile from below the substrate or the surface the tile is mounted to. With this all said, we can move on to the types of kilns used today:

Whether the tile is fired once or twice or not at all in the case of cement tiles, each type of tile has certain characteristics. These characteristics determine what application the tile should be used for. The American National Standards Institute (ANSI) together with the American Society for Testing and Materials (ASTM) has established a method for testing ceramic tiles which is found in ANSI 137.1 1988.

ANSI 137.1 1988:

The results of this testing procedure establish minimum standards for the various types of tile and trim. Also, the testing reveals certain characteristics of the tile such as:

water absorption abrasion resistance impact resistance breaking strength

stain resistance visual quality The water absorption characteristic is of particular importance as it

places the tiles into one of four types of tile.

Type of Tile Water Absorption Potential

non-vitreous tile +7.0%

semi-vitreous 3.0-7.0%

Vitreous .5-3.0%

Impervious less than .5%

The testing will result in the tile being placed in one of three categories.

Grade ANSI Requirements

Standard tile that passes all the minimum standards and will pass the visual examination at a distance of 3 feet.

Seconds will pass the minimum standards and visual exam at 10 feet.

Culls tiles that do not pass at all and are discarded or not used for their intended purpose.

Besides building green surfaces on our roofs we need solar energy harnessing. Shouldn’t our roof tiles accomplish that? Guys from SRS Energy surely think so. Solar energy is a renewable alternative to power plants that burn fossil fuels, finite resources that contribute to pollution, global warming, as well as the reliance on imports for our energy security. SRS Energy roofing systems provide an electricity-generating solution for your home with immediate savings. As a sustainable “cool roof” with high air flow, US Tile’s roof system offers an additional savings of 5 to 20 percent in typical home cooling costs.The active SRS Energy solar roofing tiles cover about 15 percent of the roof on an average home. The Solé Power Tile system, currently only available in blue, integrates with US Tile’s wide array of clay tile in a host of colors from a premium glazed blue to classic earthen hues. This system offers homeowners design flexibility while maintaining the profile of a premium clay roofing system.Each Solé Power Tile roofing tile is equipped with components that circumvent the “Christmas light” effect. This means that the failure of a single tile will NOT trigger an overall roof failure. The system is an upgrade to US Tile’s authentic clay roofing system, so it is the first environmentally-sustainable energy solution that integrates an aesthetic solar component into the purchase of a new premium roof. The TPO formulation is frequently used in rugged car bumpers. SRS Energy rigorously tests the materials for their safety, durability, and toughness in the harsh roofing environment. The tiles are also lightweight

and unbreakable. Flexible solar technology manufactured by United Solar Ovonic (UNI-SOLAR), the world leader in thin film solar, is safely imbedded in the tile.

A Solé Power Tile system takes less time than conventional solar panels to generate the amount of energy required in the production process, making them a true green product. That time represents a very small amount of the tile’s life span and its capacity to continue generating electricity over the long term. A Solé Power Tile system is guaranteed to generate electricity at a rate that equals 80 percent of its generating capacity for a period of 20 years, and is expected to continue to produce well beyond the warranty period. In addition, the polymers employed in the tile can be recycled once the product reaches the end of its life.

SRS Energy has successfully conducted product evaluations to test outdoor performance with regards to safety, long-term UV stability and color fastness, resistance to wind uplift, electrical output, durability and the extreme mechanical stresses found on a roof.

SRS Energy’s Solé Power Tile upgrade will be available in select US West Coast markets in the Fall of 2009 through US Tile. SRS Energy intends to expand its footprint into additional domestic markets as well as international markets in 2010 and 2011.

ENERGY SAVING METHOD OF MANUFACTURING CERAMIC PRODUCTS FROM WASTE GLASS

Traditionally, ceramic products have been created using raw materials that require high firing temperatures and energy intensive processing steps. The manufacture of clay-based tiles, for example, requires firing temperatures of approximately 2200°F. Ceramic products can also be produced using glass-melting methods, which require temperatures of 2700°F or more. A new technology being developed by Haun Labs has the potential to lower energy costs related to the conventional method of manufacturing ceramic products by substituting raw materials with recycled waste glass. Research has demonstrated that products created using the new processing method are less sensitive to contaminants in the glass and can be made from either green or mixed-color waste glass, which are difficult to recycle. With 100% substitution, firing temperatures for this new process can be reduced by as much as 37% (clay-based), resulting in significant reduction in energy costs and a significant increase in recycling rate. In addition, this new process resolves inherent chemical and processing incompatibilities previously encountered with the use of traditional ceramic raw materials and manufacturing methods.

NEW MANUFACTURING METHOD REDUCES ENERGY USE DURINGTHE PRODUCTION OF CERAMIC TILE FROM WASTE GLASS

Benefits Sintered recycled glass process reduces energy consumption during firing processes

by 37% compared to clay-based tiles and 50% compared to glass melt-based tiles Uses up to 100% waste glass as raw material Does not require water or clay for production

Eliminates the need for expensive, energy-intensive spray drying step needed to produce powder for dry pressing of tile

Requires only one firing step due to the rapid sintering behavior of glass powder Eliminates product molds used in some waste-glass production processes

ApplicationsThis new processing method will have immediate applications in the ceramic tile industry, where raw material and fuel costs are significant. Because ceramic tile is used in both residential and commercial floor and wall coverings, the technology will likely have mass-market appeal due to its lessenergy-intensive, recycled nature.

CERAMIC TILES MADE FROM 95-100% RECYCLED GLASSCeramic tiles produced from recycled glass offer the same quality as traditionally manufactured tiles, but require substantially less energy to produce.

Glass Tiles:

The glass tiles will be produced in the most popular sizes - 100 x 100 mm, 150 x 150 mm, 200 x 200 mm, 250 x 250 mm and 300x300 mm. The tile thickness will range from 6 to 10 mm.

They will be made in 4 main colours, white, blue, green and amber and in 4 colour variations based on the four main colours. Altogether there will initially be a choice of 8 colours and two surface choices, matt and glossy.

Use and Care

Recycled glass tiles can be used to replace traditional ceramic tiles in any situation the latter is used around the home. In particular, they are more stain resistant and chemical-resistant than porous ceramic tiles and so are ideal for use in places that are prone to high moisture, such as bathrooms and kitchens. Recycled glass tiles can also be used outdoors and special pavers made of a combination of concrete and recycled glass are available for the garden.

Care should be taken with installation as glass tiles in general require more finesse than standard ceramic tiles and it is best to find a builder familiar with the differences in installation. Points to consider include:

Making sure each tile is knocked down and smoothed for comb marks after the coat of thin set is applied; otherwise unattractive marks will be visible through the glass.

Ensuring that an even, deep layer of adhesive remains after smoothing the thin set, so that each tile is secure and supported.

Overall, taking more time and care as recycled glass generally requires more installation time and more attention given to the tiles before they are secured in place.

SMB (Stabilized Mud Blocks) :

These are dense solid blocks compacted using a machine with a mixture of soil, sand, stabilizer (cement/lime) and water. After 28 days curing, the stabilized mud blocks (SMB) are used for wall construction. Two block sizes (305 × 143 × 100 mm and 230 × 190 × 100 mm) have been standardized. These blocks are 2.5 to 2.8 times bigger in volume when compared with locally vailable conventional burnt clay bricks. Compressive strength of the block greatly depends upon the soil composition, density of the block and percentage of stabilizer (cement/lime). Sandy soils with 7% cement can yield blocks having wet compressive strength of 3–4 MPa. Higher strength for the block can be obtained by increasing the quantity of stabilizer.

What was the need For Using Alternative Building Materials:

Building Element Unit Energy per unit (MJ)

Walling materialsBurnt brick masonarySteamed Block masonrySMB masonry

Roofing systemsReinforced concrete slabSMB filler slabComposite panel roofRibbed slab roofBrick masonry vault roofSMB masonry vault roofMangalore tile roofFerroconcrete tile roof

m3m3m3

m2m2m2m2m2m2m2m2

21411396550

730590560490575418227158

Table gives the details of energy content in various types of common and alternative walling and roofing systems. The table indicates that:

Energy content of SMB masonry and steam-cured block masonry are about one fourth and two thirds of that required for the commonly used burnt brick masonry respectively,

Alternative roofing systems like SMB filler slab, composite panel roof, ribbed slab roof, etc. can be used in place of conventional reinforced concrete roof saving about 20–40% of energy, and

Ferroconcrete tile roof consumes 30% less energy when compared to conventional Mangalore tile roof.

Thus it is clear that use of alternative building technologies results in reduction of considerable amount of embodied energy in building systems.

Major advantages of SMB are:

energy efficient, do not require burning, 70% energy saving when compared to burnt bricks,

economical, 20–40% savings in cost when compared to brick masonry, plastering can be eliminated, and better block finish and aesthetically pleasing appearance.