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Performance characteristics of an energy selective electron refrigerator with double resonances 下载免费PDF全文
This paper establishes the energy selective electron (ESE) engine
with double resonances as a refrigerator in one dimensional (1D)
system. It consists of two infinitely large electron reservoirs with
different temperatures and chemical potentials, and they are
perfectly thermally insulated from each other and interaction only
via a double `idealized energy filter' whose widths are all finite.
Taking advantage of the density of state and Fermi distribution in the 1D
system, the heat flux into each reservoir may then be calculated.
Moreover, the coefficient of performance may be derived from the
expressions for the heat flux into the hot and cold reservoirs. The
performance characteristic curves are plotted by numerical analysis.
The influences of the resonances widths, the energy position of
resonance and the space of two resonances on performance of the ESE
refrigerator are discussed. The results obtained here have
theoretical significance for the understanding of thermodynamic
performance of the micro--nano devices. 相似文献
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热漏、内不可逆性和导热规律对制冷机最优性能的影响 总被引:6,自引:0,他引:6
1引言有限时间热力学研究制冷循环性能已取得了一批成果。已发表了热阻加热漏模型[1-4]、热阻加内不可逆模型问研究各种损失对卡诺循环性能的影响。本文作者用一常数项q表示热漏流率,用常系数表示热阻和热漏外的其余内不可逆性,建立了一类广义不可逆制冷机模型[6-7],并分析了牛顿传热定律下的最优性能。本文将基于此模型和较为普遍的导热规律,导出制冷机的制冷率、制冷系数最佳特性关系。2广义不可逆卡诺制冷机及其最优性能考虑一类工作在两个恒温热源之间的定常态流卡诺制冷机,循环中存在热阻、热漏和其它内不可逆性[6… 相似文献
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This paper establishes a model of a nonlinear diode refrigerator consisting of two diodes switched in the opposite directions and located in two heat reservoirs with different temperatures. Based on the theory of thermal fluctuations, the expressions of the heat flux absorbed from the heat reservoirs are derived. After the heat leak between the two reservoirs is considered, the cooling rate and the coefficient of performance are obtained analytically. The influence of the heat leak and the temperature ratio on the performance characteristics of the refrigerator is analysed in detail. 相似文献
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研究了周期性双势垒锯齿势中, 布朗粒子在外力作用下沿空间坐标方向交替地和高、低温热库接触构成的布朗热机的热力学性能. 考虑布朗粒子动能的变化以及高、 低温库之间热漏的存在, 通过数值计算分析势垒高度、势比、外力等参数对布朗热机效率的影响. 研究表明:当考虑热漏时, 布朗热机始终是不可逆的, 效率小于卡诺效率; 并且当热漏很小时, 势比的增大在一定程度上可提高布朗热机的效率; 其功率与效率之间的关系曲线为闭合线. 当不考虑热漏时, 其功率与效率之间的关系曲线为开型线, 但由于布朗粒子动能的变化引起的不可逆热流, 热机的效率依然小于卡诺效率.
关键词:
布朗热机
双势垒锯齿势
热漏
热力学性能 相似文献
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研究了具有不同温度和不同化学势的两个热库中电子通过一个双势垒InAs/InP纳米线异质结进行的传输.利用传输矩阵法得到了电子的传输概率,进而计算得到电子传输所产生的热流.通过数值计算给出了热电子制冷机的性能特征曲线.进一步分析了势垒宽度和势阱宽度对制冷机工作性能的影响.研究发现,当势阱宽度一定时,随着势垒宽度变大共振中心能级的位置变大,共振能级宽度变小,同一偏压对应的制冷率变小,相对制冷系数变大.当势垒宽度一定时,随着势阱宽度变大,同一偏压对应的相对制冷系数变小.当势垒和势阱宽度同时变化时,得到的曲线与势垒宽度一定势阱宽度变化时得到的曲线基本相似.这表明制冷率和相对制冷系数主要受势阱宽度变化的影响. 相似文献
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Feynman's ratchet and pawl: an exactly solvable model 总被引:1,自引:0,他引:1
Jarzynski C Mazonka O 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》1999,59(6):6448-6459
We introduce a simple, discrete model of Feynman's ratchet and pawl, operating between two heat reservoirs. We solve exactly for the steady-state directed motion and heat flows produced, first in the absence and then in the presence of an external load. We show that the model can act both as a heat engine and as a refrigerator. We finally investigate the behavior of the system near equilibrium, and use our model to confirm general predictions based on linear-response theory. 相似文献
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T.A. Knuuttila K.K. Nummila W. Yao J.P. Kauppinen J.P. Pekola 《Physica E: Low-dimensional Systems and Nanostructures》1998,3(4):323
We investigate electron thermalization of tunnel junction arrays installed in a powerful dilution refrigerator whose mixing chamber can produce lattice temperatures down to 3 mK. The on-chip Coulomb blockade thermometers (CBT) against other thermometers at the mixing chamber provide direct information on the thermal equilibrium between the electronic system and the refrigerator. We can detect and discriminate between the heat load delivered through the wiring and that produced by the bias current of the CBT-measurement. The basic heat leak limits the minimum of the electronic temperature to slightly below 20 mK. 相似文献
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A thermal entangled quantum refrigerator based on a two-qubit Heisenberg model with Dzyaloshinskii-Moriya interaction in an external magnetic field 下载免费PDF全文
Based on an isotropic two spin-1/2 qubits Heisenberg model with the Dzyaloshinskii-Moriya interaction in an external magnetic field, we have constructed an entangled quantum refrigerator. Expressions for the basic thermodynamic quantities, i.e., the heat exchanged, the net work input, and the coefficient of performance, are derived. Some intriguing features and their qualitative explanations in zero and non zero magnetic fields are given. The influence of the thermal entanglement on the refrigerator is investigated. The results obtained here have general significance and will be helpful to understand the performance of an entangled quantum refrigerator. 相似文献
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Taking into account the finite-rate heat transfer in the heat-transfer processes, heat leak between the two external heat reservoirs, regenerative loss, regeneration time, and internal irreversibility due to dissipation of the cycle working substance, an irreversible magnetic Ericsson heat-pump cycle is presented. On the basis of the thermodynamic properties of magnetic materials, the performance characteristics of the irreversible magnetic Ericsson heat-pump are investigated and the relationship between the optimal heating load and the coefficient of performance (COP) is derived. Moreover, the maximum heating load and the corresponding COP as well as the maximum COP and the corresponding heating load are obtained. Furthermore, the other optimal performance characteristics are discussed in detail. The results obtained here may provide some new information for the optimal parameter design and the development of real magnetic Ericsson heat-pumps. 相似文献
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研究了一维晶格中费曼棘齿-棘爪热机模型. 用粒子的概率主方程来描述粒子在晶格中的动力学特性, 推导出热流、 功率和效率的表达式. 通过数值计算分析势垒高度、 外力和温比对热流以及热机功率和效率的影响. 研究表明: 在粒子稳态概率流为零时, 存在非零的热流从高温库流入低温库, 类似于经典不可逆卡诺模型中的热漏; 热漏的存在使得热机的效率远远小于卡诺效率, 功率与效率之间为闭合的关系曲线, 热机为不可逆热机; 对热机性能参数进行优化, 可以使热机工作在最优性能状态下. 相似文献
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废热溴化锂制冷机可以直接利用烟气废热或化学反应热来驱动进行制冷,因此废热回收的综合利用率比较高。论文对烟气废热驱动废热溴化锂制冷机的热能利用的经济性进行了分析,在烟气废热驱动溴化锂制冷机中,溴化锂制冷机的COP仅仅反映的是溴化锂制冷机本身的性能,不能作为衡量废热溴化锂制冷机废热制冷的效率高低和性能好坏的标准,因此本文采用废热利用率和废热制冷率对烟气废热溴化锂制冷机的废热制冷性能指标,废热制冷率与炯效率分析结果相一致,通过比较发现,二级烟气双效废热驱动废热溴化锂制冷机的废热制冷率最高,炯效率也最高。 相似文献
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Experimental investigation of a thermoacoustic-Stirling refrigerator driven by a thermoacoustic-Stirling heat engine 总被引:1,自引:0,他引:1
In this paper, a thermally-driven thermoacoustic refrigerator system without any moving part is reported. This refrigeration system consists of a thermoacoustic-Stirling heat engine and a thermoacoustic-Stirling refrigerator; that is, the former is the driving source for the latter. Both the subsystems are designed to operate on traveling-wave mode. In the experiment, it was found that the DC-flows had significant negative effect on the heat engine and the refrigerator. To suppress these DC-flows, two flexible membranes were inserted into the two subsystems and worked very well. Then extensive experiments were made to test the influence of different parameters on refrigeration performance of the whole system. The system has so far achieved a no-load temperature of -65 degrees C, a cooling capacity of about 270 W at -20 degrees C and 405 W at 0 degrees C; in fact, the result showed a good prospect of the refrigeration system in room-temperature cooling such as food refrigeration and air-conditioning. 相似文献