Three-level laser heat engine at optimal performance with ecological function

Abstract

Although classical and quantum heat engines work on entirely different fundamental principles, there is an underlying similarity. For instance, the form of efficiency at optimal performance may be similar for both types of engines. In this work, we study a three-level laser quantum heat engine operating at maximum ecological function (EF) which represents a compromise between the power output and the loss of power due to entropy production. We derive analytic expressions for efficiency under the assumptions of strong matter-field coupling and high bath temperatures. Upper and lower bounds on the efficiency exist in case of extreme asymmetric dissipation when the ratio of systembath coupling constants at the hot and the cold contacts respectively approaches, zero or infinity. These bounds have been established previously for various classical models of Carnot-like engines. We conclude that while the engine produces at least 75% of the power output as compared with the maximum power conditions, the fractional loss of power is appreciably low in case of the engine operating at maximum EF, thus making this objective function relevant from an environmental point of view.

Unified trade-off optimization of quantum harmonic Otto engine and refrigerator

“…which concurs with the efficiency of the endoreversible and symmetric low-dissipation models of heat engines [29,47]. The results are not surprising as in the hightemperature regime (classical regime), the engines are expected to behave like classical heat engines [24,28,48]. Eq.…”

“…The universality of the EMOF was first formally proven by Zhang and coauthors [53] by using the framework of stochastic thermodynamics. The first two terms 3η C /4 and η 2 C /32 were also obtained for endoreversible [29,54], low-dissipation [47], minimally nonlinear irreversible [55] and some other models of classical and quantum heat engines [28,54,56].…”

“…Interestingly, it is not the only case in which a quantum heat engine can be mapped to Feynman's ratchet and pawl engine. Recently, a three-level laser quantum heat engine operating in the low-temperature regime was also mapped to Feynman's model [28].…”

“…One is usually interested in optimizing the power output of a heat engine and its corresponding efficiency [12][13][14][15][16][17][18][19][20][21][22][23], whereas, for a refrigerator, the most desirable figure of merit is cooling * varinder@ibs.re.kr power [11,[24][25][26]. A well-known observation that the thermal engines operating at maximum power also dissipate a large amount of power due to entropy production, which ultimately pollutes the environment [7,27,28]. Therefore, instead of operating engines (refrigerators) in the maximum power (cooling power) regime, the real irreversible thermal machines should operate near the maximum power point where they yield considerably higher efficiency with a significant reduction in entropy production.…”

Optimization and Efficiency Studies of Heat Engines: A Review

“…56,59 Further, it has been shown that the quadratic coefficient 1/32 is also universal for the strongly coupling systems with the left right symmetry. 56 The universality of such an efficiency has been investigated in different heat engines such as stochastic Brownian heat engines, 60 Feynman ratchet heat engines, 60 quantum dot heat engines, 60 low-dissipation heat engines, 61 classical heat engines, 62 and minimally nonlinear irreversible heat engines 63 and laser quantum heat engine 64 Another optimization criterion is Efficient power, defined as the product of efficiency and power (ηP), pays equal attention to both the efficiency and the poweroutput, was first proposed in Refs. [65,66] and further extended in studies.…”