Handout 1: Carbon emissions and environmentalenergy sourcesCarbon emissionsWithin the United Kingdom, domestic and commercial/industrialbuildings possibly present the biggest opportunity for achieving the20% reduction in carbon dioxide emissions targeted by the governmentby 2016. However, due to the differing age range and overall conditionof the UKs housing stock that target is proving challenging to attain.Carbon emissions from buildingsAlthough carbon emissions in the UK have remained fairly stable since1990, buildings accounted for approximately 30% of all emissions in2009 (40 million tonnes of carbon) which is an increase from 26.4% ofthe UK’s overall production in 1990. Research undertaken by TheSelect Committee on Environmental Audit calculated that this figurecould rise to over 55% in 2050.
Handout 1: Carbon emissions and environmentalenergy sourcesZero carbon ambitionIn the 2006 Pre-Budget Report the then government announcedtheir aspiration that all newly built homes would be zero carbonby 2016. To encourage this, they offered an exemption fromstamp-duty.Domestic energy usageBuildings in the UK are amongst the least energy efficient inEurope. During 2009 it was calculated that 30.2% of all energyuse was used for space heating, water heating, lighting andcooking purposes, again up from 1990 which stood at 27.7%.The figures for energy consumed during 2009•Space heating - 60% (57% in 1990)•Water heating - 23% (25% in 1990)•Appliances and lighting - 13% (13% in 1990)•Cooking - 2% (3% in 1990)
Handout 1: Carbon emissions and environmentalenergy sourcesThe building services engineering industry is attempting to tacklethese problems by installing or upgrading buildings to meet thegovernment’s guidelines. This can be attained by the installationof:•energy efficient boilers•solar installations to harness the free energy from the sun•wind power•grey water and rain water harvesting•air source heat pumps•ground source heat pumpsSolar powerThere are two methods of using the free energy from the sun andharnessing it to heat buildings or create useable electricity toreduce the costs of heating or lighting buildings.These are:
Handout 1: Carbon emissions and environmentalenergy sourcesSolar thermalThis is where an ‘evacuated tube’ solar panel is used to indirectly heat the water withinthe hot water cylinder. There are two versions of this which are the drain-back systemand the sealed system.The drain-back system, as its name explains is one that when the circulating pump isswitched off, the primary water is allowed to drain out of the tubes in the panel to aninternal reservoir to prevent the problem of freezing in the winter months.The sealed system is a fully sealed installation that can only be filled by the use of a‘filling loop’. It does not drain itself at pump shutdown and the problem of freezing inwinter months is overcome by the addition of Glycol(antifreeze) to the primary water.
Handout 1: Carbon emissions and environmentalenergy sourcesSolar photovoltaicThis method of harnessing thesun’s energy uses a differenttype of panel that transforms theenergy from the sun into a‘direct’ electrical current (dccurrent). This dc current can beused in this form or transformedvia an ‘inverter’ into an‘alternating’ current (ac current)that can be used around thehome for powering electricalappliances or if not used, sold tothe electricity suppliers to beused elsewhere.
Handout 1: Carbon emissions and environmentalenergy sourcesWind powerThe power of the wind can be harnessed to create energy foruse in buildings by using a wind turbine. These turbines comein two forms,Horizontal axisThis is where the blades are mounted like a windmill and arerotated via the wind to produce reusable energy. Theseblades themselves have to be rotated to face into the wind foroptimum generation.Vertical axisVertical axis turbines do not need orientation to the wind andare generally used for smaller energy generation use.
Types of wind turbineHandout 1: Carbon emissions and environmentalenergy sources