Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/47788
標題: Performance of a Multi-Bed Adsoprtion Heat Pump for Operating at Unequal Mode Times in a Cycle
多床吸附式熱泵在非等模式操作時間下之性能研究
作者: 沈君洋
關鍵字: 應用研究
adsorption heat pump
能源工程, 機械工程類
吸附式熱泵
冷卻能力
COP
熱力學第二定律
specific cooling power
COP
second law
摘要: An improvement of the COP and specific cooling power for a closed-typemulti-bed adsorption heat pump (Fig. 1), designed and assembled by the MechanicalEngineering Department of the National Chung Hsing University, is proposed. Theadsorption heat pump contains four adsorbers, one condenser, one evaporator and oneexpansion device (Fig. 2). Two adsorption pairs, silica gel-water and SWS-1Lcomposite adsorbent-water, are individually considered. At the present stage, during acyclic operation, the adsorbers consecutively and orderly proceed to four differentmodes - adsorption, preheating, regeneration and precooling (Fig. 3). After completingthe four modes, every adsorber will return to its original mode. At this time, a cycle iscompleted and the system will proceed to the next cycle. In the above arrangement, themode operating times of the four processes are the same. However, according to aprevious analysis, the result shows that the mode operating time of the preheating andprecooling processes can be shorter than that of the regeneration and adsorptionprocesses. For a fixed cycle time, if the mode operating time of the preheating andprecooling processes is reduced for prolonging the mode operating time of theregeneration and adsorption processes, the cooling capacity of the adsorption heatpump will be increased. In addition, the extra regeneration heat for increasing thecooling capacity is purely the heat required for desorption. There is no additional heatneeded for heating the adsorber. Hence, the COP can also be upgraded. In this work,the performance of the adsorption heat pump for operating under unequal modeoperating times will be investigated. It intends to obtain the optimum mode operatingtime for the preheating and precooling processes, as well as the optimum modeoperating time for the regeneration and adsorption processes. Both experimentalmeasurement and computer simulation are arranged. In the computer simulation, asolid-side resistance model will be adopted for analyzing the heat and mass transfer inthe adsorber. The COP and cooling capacity of the adsorption heat pump for variousoperating conditions will be obtained. In addition, a second-law analysis for analyzingthe exergy losses in each component and each process will be performed. The obtaineddata will be useful to finding strategies for upgrading the COP of the adsorption heatpump.
此研究擬針對一個由此研究單位(中興大學機械系)設計組裝之密閉型多床吸附式熱泵(如圖1 所示)進行改良,以提昇其熱能使用效率(COP)與冷卻能力。此系統主要包含四個吸附器、一個冷凝器、一個蒸發器與一個膨脹裝置(如圖2 所示),在一個週期循環中(one cycle),此熱泵中每一個吸附器均歷經吸附、預熱、再生與預冷等四個過程(如圖3 所示),研究中系統分別考慮使用兩種不同之吸附配對(矽膠-水與SWS-1L 複合吸附劑-水)。在現階段之系統中,四個吸附器在同一時間中分別進行吸附、預熱、再生與預冷等四個過程,每個吸附器在每個過程結束後,依上述所排列之程序,分別進行下一過程,當完成單一之系統循環時,此時四個吸附器會分別回到原始進行之四個過程,而系統會依相同之模式繼續進行下一個循環。上述之安排亦即代表每個過程之操作時間(mode operating time)均相同,但由先前研究之結果顯示,在一個系統循環中,預熱與預冷等兩個過程之操作時間可以較再生與吸附等兩個過程之操作時間為短,在固定之週期操作時間下,若將預熱與預冷等兩個過程縮短之操作時間分別提供給吸附與再生等兩個過程,則系統之冷卻能力應該可以增加,同時用以增加此冷卻能力所需耗費之再生熱量單純為吸附熱,無需增加用於加熱吸附器所需耗費之熱量,因而系統之COP 亦會提昇。此研究擬針對上述之非等操作時間下之系統性能進行探討,以期得到最佳之預熱與冷卻時間與最佳之吸附與再生時間,此研究將同時進行實驗之量測與電腦之模擬分析,模擬分析乃採用考慮具吸附劑固體側質傳擴散阻力之吸附模式,以分析吸附器中之熱質傳,進而得到各種操作狀態下熱泵之冷卻能力與COP,此研究同時擬進行系統之熱力學第二定律分析,以探討系統中各元件與各過程之有效功耗損(exergy loss),此分析之結果將有助於尋求提昇系統COP 之方法。
URI: http://hdl.handle.net/11455/47788
其他識別: NSC97-2221-E005-043-MY2
文章連結: http://grbsearch.stpi.narl.org.tw/GRB/result.jsp?id=1756358&plan_no=NSC97-2221-E005-043-MY2&plan_year=98&projkey=PB9801-1936&target=plan&highStr=*&check=0&pnchDesc=%E5%A4%9A%E5%BA%8A%E5%90%B8%E9%99%84%E5%BC%8F%E7%86%B1%E6%B3%B5%E5%9C%A8%E9%9D%9E%E7%AD%89%E6%A8%A1%E5%BC%8F%E6%93%8D%E4%BD%9C%E6%99%82%E9%96%93%E4%B8%8B%E4%B9%8B%E6%80%A7%E8%83%BD%E7%A0%94%E7%A9%B6
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