Life Cycle Optimization of Residential Air Conditioner Replacement

emphasize sensible cooling capacity. The model only uses SEER to model efficiency and thus aregional standard based only on SEER is necessary for evaluation so the southeastern region wasselected.Unlike the previous analysis which assumed a new unit was purchase at the start of 1985, thisanalysis was done in order to evaluate the impacts from different aged systems from 2009 till2025. In essence, the model was modified by decreasing the time horizon to start at 2009 andexamining the results till 2025. In this case, the environmental burdens and consumersexpenses that occur before 2009 are ignored, but the burdens and costs thereafter areconsidered. The process LCA results are used to model the burdens from the production ofsubsequent units.Location profiles were created for each of the states in the region. A population weightedcooling load hour average (U.S. Census Bureau, 2009; Energy Star, 2009) was found for eachstate. The national temperature distribution was used to calculate the effective SEER for all thestates. The largest NERC region by area was used for each state in states where more than oneNERC region was present.It was assumed that a new regional standard of 16 SEER would take place at the start of 2009.While it is more likely that such a standard would be implemented in 2016 along with a revisednational standard, this is only 10 years before the end of the time horizon and thus in manyoptimization scenarios the final replacement would occur before such a regional standard wasadopted. Thus for the purposes of understanding the impact of a regional standard, the 16 SEERstandard was assumed to begin at the start of 2009. Process LCA results were used for theanalysis. The results for selected initial model years for selected states in the region are shownin Table 6.2. Results for all states are given the Appendix.Table 6.2: LCO Savings from Regional Standard Compared to Base Case Efficiency Scenariofor Select States and Initial Model Years.StateYear ofCAC in2009 ObjectiveAL 1997orbeforeFL 1997orbeforeBase Case Efficiency 16 SEER Regional Standard SavingsDates ofOptimalDates ofOptimalfromRegionalReplacementObjective Replacement StandardEnergy (MJ) 2009, 2016 913,000 2009, 2017 793,000 13.2 %GHG (CO2 eq.) 2009 52,700 2009 46,800 11.2 %Cost (2009$) 2009 $13,500 2009 $12,810 5.1 %2003 Energy (MJ) 2009, 2016 913,000 2009, 2017 793,000 13.2 %GHG (CO2 eq.) 2009 52,700 2009 46,800 11.2 %Cost (2009$) 2003, 2013 $13,190 2003, 2013 $12,700 3.7 %2008 Energy (MJ) 2008, 2015 907,000 2009, 2017 793,000 12.6 %GHG (CO2 eq.) 2008, 2015 51,200 2008, 2011 46,500 9.2 %Cost (2009$) 2008, 2016 $12,610 2008, 2013 $12,190 3.4 %Energy (MJ) 2009, 2013, 1,455,000 2009, 2017 1,260,000 13.4 %2019GHG (CO2 eq.) 2009 72,200 2009 63,500 12.0 %Cost (2009$) 2009 $20,550 2009 $18,850 8.2 %