This paper studies ecological performance by taking a quantum Carnot heat pump asobject. The working substance of the heat pump is harmonic oscillator. Besides heatresistance, this heat pump also has heat leakage and internal friction. This paper derivesheating load, coefficient of performance and ecological function and analyse theseimportant parameters with numerical illustrations. At high temperature limit, this papersimplifies these important parameters and deduces the optimal performance by takingecologicalfunctionasobjective.Also,thispaperillustrateseffectsofirreversibilitieswithhelp of numerical calculation. The results reveal that ecological function of the pumphas maximum value. Results at high temperature limit reveal that ecological functionversus COP characteristic curves are parabolic-like as when heat leakage is absentand ecological function has maximum value. Heat leakage makes characteristic curvesbecome loop-shaped curves and leads to smaller ecological function and COP. Witha constant heat leakage, maximum attained ecological function decreases as internalfriction increases. Comparison between maximum points of ecological function and COPathightemperaturelimitrevealsthatecologicaloptimizationmakesCOPdecrease16.8%,exergy loss rate increases about 7.20 times, but heating load and exergy output rategreatly increase about 3.18 times and 3.23 times, respectively. Comparison maximumpoint of ecological function and point where the value of exergy output rate isA/τ=6.09×10−4reveals that the second point makes COP decrease 5.21%, exergy outputrate increase only 20.9% and heating load increase only 21.1%, but the exergy loserate increases 40.7%. Taking maximum ecological function as objective makes largerimprovement in COP and reduction in exergy loss rate, and the cost is smaller heatingload drop.
