This work determines optimal energy system configurations that minimize CO2 emissions under three typical grid electricity generation sources: (a) mostly nuclear and hydro; (b) natural gas; (c) coal. Benefits of implementing ground source heat pump (GSHP) and air source heat pump (ASHP) are compared to using combined cooling-heating-power (CCHP) system considering meeting cooling, heating, and electricity demands of consumers. GSHP is modeled via a novel multilayer model of borehole field heat transfer. Results from case studies show that for regions using mainly renewable energy technologies, configuration anchored on GSHP + ASHP has the lowest emissions, while configurations anchored on ASHP or ASHP + CCHP emit 5% more. When electricity is generated from natural gas or coal, relative to the configuration with the lowest emissions (all equipment), configurations anchored on GSHP + CCHP emits 1% and 2% more, while configurations anchored on ASHP + CCHP emit 3% and 19% more, respectively.
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