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Life Cycle Analysis of Hand-dryers for NDSU. La Toya Kissoon David Mushet Xiana Santos. Introduction. Obj: Replacement of 100 folded-paper towel dispensers with either motion-sensing paper towel dispensers or warm air hand dryers
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Life Cycle Analysis of Hand-dryers for NDSU La Toya KissoonDavid MushetXiana Santos
Introduction • Obj:Replacement of 100 folded-paper towel dispensers with either motion-sensing paper towel dispensers or warm air hand dryers • Purpose: to determine which hand drying method used at (NDSU) bathroom facilities produces least impacts on the environment.
Life Cycle Inventory • Inputs (material and resource) and outputs (emission and product) from unit processes in the life cycle of each hand dryer type was identified and quantified. • Data was collected from both primary and secondary sources. • Secondary data was collected from existing databases associated with GaBi software.
Calculating the Number of Uses / Dispenser We used information on towel dispenser use at NDSU’s Stevens Hall to estimate uses / dispenser. We obtained an estimate of the number of boxes of towels used / year at Stevens Hall from Chad, NDSU Maintenance Staff. We observed use habits to estimate the number of towels used during the hand drying process. Finally, we tallied the total number of towel dispensers in Stevens Hall.
Calculating the Number of Uses / Dispenser (cont.) (40 boxes/yr) (4000 towels/box) = (3 towels/use) (10 dispensers) 5,333 uses/dispenser/year Thus, we estimated that the 100 dispensers at NDSU would receive approximately 533,300 uses / year
Calculating Paper Usage Folded Paper Towel Dispensers (533,300 uses/yr) (6.63 g/use) = 3536 kg/yr Motion-Sensing Towel Dispensers (533,300 uses/yr) (3.51 g/use) = 1872 kg/yr Warm-air Hand Driers (533,300 uses/yr) (0 g/use) = 0 kg/yr
Calculating Power Usage Folded Paper Towel Dispensers 0 MJ/yr Motion-Sensing Towel Dispensers (533,300 uses/yr) X (1 sec/use) X (hr/3600 sec) X (1.2 kWh/hr) X (3.6 MJ/kWh) = 640 MJ/yr Warm-air Hand Driers (533,300 uses/yr) X (55 sec/use) X (hr/3600 sec) X (2.4 kWh/hr) X (3.6 MJ/kWh) = 70,396 MJ/yr
GaBi 4 Inputs Folded Paper Towel Dispensers 3536 kg/yr paper 0 MJ/yr power Motion-Sensing Towel Dispensers 1872 kg/yr paper 640 MJ/yr power Warm-air Hand Driers 0 kg/yr paper 70,396 MJ/yr power
GaBi 4 Inputs Table 1 Material and resource inputs associated with folded-towel dispensers, motion sensing dispenser, and warm-air hand dryers. All values are in kilograms (kg).
GaBi 4 Outputs All values are in kilograms (kg).
GaBi Outputs All values are in kilograms (kg)
Interpretation of results • Environmental Impacts: motion sensing dispensers < Folded-paper towel dispensers < warm-air hand-dryers • Folded-paper towel dispensers - 6.63 g per usage (no control over usage – uneconomical dispensing method) • Motion-sensing dispensers - 3.51 g per usage/little energy usage (controls usage saves paper cuts down on waste environmental advantage) • Warm Air Dryers – significant environmental damage – very high inorganic emissions to air & water
Conclusions • Our LCA rated the motion-sensing towel dispensers as having the smallest environmental impact (Recommend its use due to smaller environmental impact) • Greater efficiency of dispensing method accounted for less environmental impact • Impacts associated with production, shipment and paper-waste disposal of the two paper dispensers could not compare with the energy expenditure and emissions of the warm-air dryers
References American Dryer Corp. 2006. Protect the global environment with American Hand Dryer. American Dryer, Inc., Livonia MI.http://www.americandryer.com/environment.html IKP. 2006. GaBi 4 Software. University of Stuttgart, Institute for Polymer Testing and Polymer Science, Leinfelden-Echterdingen, Germany.www.gabi-software.de Acknowledgements Chad from Stevens Hall