低溫熱源噴射式發(fā)電制冷復合系統(tǒng)特性分析

鄭彬，翁一武，顧偉，翁史烈

(上海交通大學機械與動力工程學院，上海市閔行區(qū)200240)

Analysis of a Combined Powerand Ejector Refrigeration Cycle for

Low Temperature Heat Sources

ZHENG Bin，WENG Yi—wu，GU Wei，WENG Shi—lie

(School of Mechanical and Power Engineering，Shanghai Jiao Tong University，Minhang District，Shanghai 200240，China)

ABSTRACT：A combined power and refrigeration cycle isproposed.The proposed cycle combines the organic Rankinecycle and the ejector refrigeration cycle，producing power as,ell as refrigeration simultaneously.The ejector is driven by the exhausts from the turbine.After the efficiency definition of the combined cycle，a simulation model was established for calculation and analysis.R245fa Was chosen as the working fluid for its good performance.At the typical working conditions generating temperature T92120。C，evaporating temperature Te=7"(2 and condensing temperature Tc=25’C，the first law efficiency of the combined cycle Can be 37%，the practical first law efficiency Can be 15.6%and the exergy efficiency Call be 37.5%.Results show that performance of the cycle call benefit from increasing generating temperature，increasing evaporating temperature and decreasing condensing temperature瓦.It is found that larger power refrigeration ratio R Can be obtained by increasing expansion ratio 8.

KEY WoRDS：combined power and refrigeration cycle;organic Rankine cycle;ejector refrigeration cycle;waste heat recovery;low temperature heat sources

摘要：提出一種低溫熱源噴射式發(fā)電制冷復合系統(tǒng)。該系統(tǒng)將有機物朗肯循環(huán)與噴射式制冷循環(huán)相結(jié)合，利用透平排氣驅(qū)動噴射器工作，同時實現(xiàn)發(fā)電和制冷的功能。在定義系統(tǒng)評價指標的基礎(chǔ)上，選取性能優(yōu)良的有機物R245fa作為工質(zhì)，建立系統(tǒng)仿真模型，進行計算分析。計算結(jié)果表明，在熱源蒸發(fā)溫度7≯120"C。制冷蒸發(fā)溫度7≯7℃，冷凝溫度Te=25"C的標準工況下，系統(tǒng)的熱力學第一定律效率可達37%，熱力學第一定律折合效率可達15.6%，煙效率可達37.5%。分析同時表明，提高熱源蒸發(fā)溫度疋，提高制冷蒸發(fā)溫度瓦，降低冷凝溫度疋，有利于提高系統(tǒng)的工作性能;提高透平膨脹比網(wǎng)以提高系統(tǒng)電冷比R。

關(guān)鍵詞：發(fā)電制冷復合系統(tǒng);有機物朗肯循環(huán);噴射式制冷循環(huán);余熱利用;低溫熱源

0引言

目前，在能源利用過程中產(chǎn)生的低溫余熱往往被直接排放到環(huán)境中去，這樣既浪費了大量的能源，又對環(huán)境造成了污染。伴隨著世界范圍內(nèi)能源供給的口趨緊張，尋找合理利用低溫熱源的方法已經(jīng)成為當前能源技術(shù)領(lǐng)域中的一個重要課題。近年來，國內(nèi)外諸多學者相繼提出了一些熱源溫度在100，350℃之間的動力，制冷復合循環(huán)能源利用的新途徑。