Adsorbents are important components in adsorption refrigeration. The diameter of an adsorbent can affect the heat and mass transfer of an adsorber. The effect of particle diameter on effective thermal conductivity was...Adsorbents are important components in adsorption refrigeration. The diameter of an adsorbent can affect the heat and mass transfer of an adsorber. The effect of particle diameter on effective thermal conductivity was investigated. The heat transfer coefficient of the refrigerant and the void rate of the adsorbent layer can also affect the effective thermal conductivity of adsorbents. The performance of mass transfer in the adsorber is better when pressure drop decreases. Pressure drop decreases with increasing permeability. The permeability of the adsorbent layer can be improved with increasing adsorbent diameter. The effect of adsorbent diameter on refrigeration output power was experimentally studied. Output power initially increases and then decreases with increasing diameter under different cycle time conditions. Output power increases with decreasing cycle time under similar diameters.展开更多
The performance of a two-state quantum engine under different conditions is analyzed. It is shown that the efficiency of the quantum engine can be enhanced by superposing the eigenstates at the beginning of the cycle....The performance of a two-state quantum engine under different conditions is analyzed. It is shown that the efficiency of the quantum engine can be enhanced by superposing the eigenstates at the beginning of the cycle. By employing the finite-time movement of the potential wall, the power output of the quantum engine as well as the efficiency at the maximum power out- put （EMP） can be obtained. A generalized potential is adopted to describe a class of two-level quantum engines in a unified way. The results obtained show clearly that the performances of these engines depend on the external potential, the geometric configuration of the quantum engines, and the superposition effect. Moreow^r, it is found that the superposition effect will en- large the optimally operating region of quantum engines.展开更多
基金Supported by the Chinese Academy of Science Visiting Professorship for Senior International Scientists project(2009Z2-1973)
文摘Adsorbents are important components in adsorption refrigeration. The diameter of an adsorbent can affect the heat and mass transfer of an adsorber. The effect of particle diameter on effective thermal conductivity was investigated. The heat transfer coefficient of the refrigerant and the void rate of the adsorbent layer can also affect the effective thermal conductivity of adsorbents. The performance of mass transfer in the adsorber is better when pressure drop decreases. Pressure drop decreases with increasing permeability. The permeability of the adsorbent layer can be improved with increasing adsorbent diameter. The effect of adsorbent diameter on refrigeration output power was experimentally studied. Output power initially increases and then decreases with increasing diameter under different cycle time conditions. Output power increases with decreasing cycle time under similar diameters.
基金supported by the National Natural Science Foundation of China(Grant No.11005041)the Program for Prominent Young Talents in Fujian Province University(Grant No.JA12001)+2 种基金the Natural Science Foundation of Fujian Province(Grant Nos.2010J05007 and 2011J01012)the Fundamental Research Funds for the Central Universities(Grant No.JB-SJ1005)the Science Research Fund of Huaqiao University(Grant No.09BS510)
文摘The performance of a two-state quantum engine under different conditions is analyzed. It is shown that the efficiency of the quantum engine can be enhanced by superposing the eigenstates at the beginning of the cycle. By employing the finite-time movement of the potential wall, the power output of the quantum engine as well as the efficiency at the maximum power out- put （EMP） can be obtained. A generalized potential is adopted to describe a class of two-level quantum engines in a unified way. The results obtained show clearly that the performances of these engines depend on the external potential, the geometric configuration of the quantum engines, and the superposition effect. Moreow^r, it is found that the superposition effect will en- large the optimally operating region of quantum engines.
