蒸氣壓縮雙溫冷凍冷藏系統最佳運轉及可用能研究分析

Research and Analysis of Optimize the Operation and Exergy for Dual-Temperature Vapor Compression Refrigeration System

許晉維(Ching-Wei Hsu)

指導教授 ： 卓清松

國立臺北科技大學/機電學院/能源與冷凍空調工程系碩士班/碩士(2011年)

摘要

本研究旨在研究壓縮機變頻技術以及電子式冷媒節流膨脹裝置應用在商用雙溫冷凍冷藏設備節能效益，利用熱力學第二定律理論分析本實驗系統中各主要元件之可用能損失分析；本研究以實驗架設一組雙溫冷凍冷藏實驗機，並設計一中間冷卻器(Intercooler)來增加系統過冷度(Subcool)以及減少過熱度(Superheat)，模擬庫體在不同負荷與壓縮機不同運轉頻率的情況下，探討系統的消耗功率、製冷速率、可用能損失分析、壓縮功、性能係數(Coefficient of Performance COP)以及能源因數(Energy Factor)的變化趨勢等等；實驗結果顯示，壓縮機在50Hz 頻率運轉模式下有相似於60Hz 運轉下的製冷效率，但其能源因素約較60Hz 運轉下節省17.3%；電子式的雙溫冷凍冷藏機組在系統穩定運轉後，其性能係數約優於機械式冷凍機組約17.6%；可用能研究方面，系統中可用能損失最嚴重的兩個元件分別為壓縮機以及冷凍膨脹閥；這兩種主要的元件加總下來的可用能損失約占整體系統可用能損失60%~70%；電子式的機組可用能損失會較機械式機組減少約30%；E.F值的表現方面，電子式雙溫冷凍機組在壓縮機運轉頻率在60Hz、50Hz、40Hz 模式下，E.F 值較機械式雙溫冷凍機組分別高出7.6%、5.23%、4.7%。由上述研究結果可得知，當壓縮機定頻50Hz 運轉，且將機械式節流冷媒控制裝置改為電子式，在長時間運轉下來的耗電、可用能損失以及能源因素方面會有較佳的表現。

關鍵字

雙溫冷凍系統 ； 可用能；第二定律 ； 電子膨脹閥

並列摘要

This study aimed to discuss the energy-saving benefit of using compressor frequency conversion technology and electronic refrigerant throttling expansion device in commercial dual-temperature refrigerating and cold storage equipments. It used the second law of thermodynamics to analyze the available energy loss of the major components of this experimental system. This study set up a Dual-temperature refrigerating and cold storage experimental machine in the experiment, and designed an
intercooler to increase the system subcool and to reduce the superheat. It simulated the storage under different loads and different operating frequencies of compressor to
discuss the variance trend of the consumed power, refrigerating velocity, available energy loss analysis, compression work, coefficient of performance (COP) and energy factor of the system. The experimental result showed that the refrigeration efficiency of the compressor working at 50Hz is similar to that at 60Hz, but the energy factor is about 17.3% lower than that at 60Hz. When the system is in steady operation, the COP of the electronic two-temperature refrigerating and cold storage machine is about 17.6% better than the mechanical refrigerating machine. As for the available energy, the two components having the most severe available energy loss in the system are the compressor and the refrigeration expansion valve. The total available energy loss of the two major components is about 60%~70% of that of the overall system. The available energy loss of the electronic machine is about 30% lower than the mechanical machine.As for the performance of E.F value, when the operating frequency of the compressor is 60Hz, 50Hz and 40Hz, the E.F value of the electronic two-temperature refrigerating machine is higher than that of the mechanical two-temperature refrigerating machine by 7.6%, 5.23% and 4.7% respectively. According to the above results, When the compressor is running fixed-frequency 50Hz and the mechanical throttle refrigerant
control device is changed to electronic type, the system has better performance in power consumption, available energy loss and energy factor in the long term.

並列關鍵字

Dual-Temperature Refrigeration System ； Exergy ； Second Law ； Electronic Expansion Valve

參考文獻

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