| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1734520 | Energy | 2011 | 9 Pages |
After introducing the concepts of moisture entransy, moisture entransy dissipation and thermal resistance based on moisture entransy dissipation (TRMED) in part I of this study, we further analyze several direct/indirect evaporative cooling processes based on the above concepts in this part. The nature of moisture entransy, moisture entransy dissipation and TRMED during evaporative cooling processes was reexamined. The results demonstrate that it is the moisture entransy, not the enthalpy, that represents the endothermic ability of a moist air, and reducing the entransy dissipation by both enlarging the thermal conductance of heat and mass transfer, and decreasing the temperature potential of the moist air, i.e. the difference between the dry-bulb temperature of moist air over its dew-point temperature, will result in a smaller system TRMED, and consequently a better evaporative cooling performance. Then, a minimum thermal resistance law for optimizing evaporative cooling systems is developed. For given mass flow rates of both moist air and water, with prescribed moist air and water conditions, minimizing the TRMED will actually lead to the most efficient evaporative cooling performance. Finally, the thermal conductance allocation for an indirect evaporative cooling system is optimized to illustrate the application of the proposed minimum thermal resistance law.
► Based on the newly introduced moisture entransy theory, several practical evaporative cooling systems are analyzed and optimized. ► The moisture entransy, not the enthalpy, is the physical quantity that represents the endothermic ability of a moist air. ► The entransy dissipation and thermal resistance connects the evaporative cooling effectiveness directly to the irreversibility of coupled heat and transfer process. ► Minimizing the thermal resistance will actually lead to the most efficient evaporative cooling performance. ► The effective ways to improve evaporative cooling performance can be easily developed through the expression of thermal resistance.
