Eco Audit White Paper. - Granta Design

A portable space heaterThe space heater in Figure 17 is carried asequipment on a light goods vehicle used forrailway repair work. A bill of materials for thespace heater is shown in Table 7 (overleaf). Itburns 0.66 kg of LPG per hour, delivering anoutput of 9.3 kW (32,000 BTU). The air flow isdriven by a 38 W electric fan. The heaterweighs 7 kg. The (approximate) bill of principalmaterials is listed in the table. The product ismanufactured in South Korea, and shipped tothe US by sea freight (10,000 km) then carriedby 32 tonne truck for a further 600 km to thepoint of sale. It is anticipated that the vehiclecarrying it will travel, on average, 420 km perweek, over a 3-year life, and that the heateritself will be used for 2 hours per day for20 days per year. This is a product that usesenergy during its life in two distinct ways. Firstthere is the electricity and LPG required tomake it function. Second, there is the energypenalty that arises because it increases theweight of the vehicle that carries it by 7 kg.What does the overall energy and CO 2 lifeprofile of the heater look like?The tool, at present, allows only one type ofstatic-use energy. The power consumed byburning LPG for heat (9.3 kW) far outweighsthat used to drive the small electric fan-motor(38 W), so we neglect this secondcontribution. It is less obvious how this staticuseenergy, drawn for only 40 hours per year,compares with the extra fuel-energyconsumed by the vehicle because of theproduct weight—remembering that, as part ofthe equipment, it is lugged over 22,000 km peryear. The Eco Audit Tool can resolve thisquestion.Table 7: Space heater, bill of materials. Life: 3 years.Component Material ProcessHeater casingFanAir flowenclosure(heat shield)Motor, rotor andstatorMotor, wiring:conductorsMotor, wiring:insulationConnectinghose, 2 meterHose connectorOthercomponentsLow carbonsteelLow carbonsteelStainlesssteelIronCopperPolyethyleneNaturalRubber (NR)BrassProxymaterial -polycarbonateForging,rollingForging,rollingForging,rollingForging,rollingForging,rollingPolymermoldingPolymermoldingForging,rollingProxy—polymermoldingMass(kg)5.40.250.40.130.080.080.350.090.22Figure 17. A space heater powered by liquid propanegas (LPG).Figure 18. The energy breakdown for the space heater.The use phase dominates.The CES EduPack Eco Audit Tool 14 © 2012, Granta Design