本文選題：低品位熱源 + 吸收式制冷�。� 參考：《山東建筑大學(xué)》2014年碩士論文

【摘要】：吸收式制冷是一種可以利用余熱、廢熱、太陽(yáng)能等低品位熱源作為驅(qū)動(dòng)方式的制冷方式,其常用的工質(zhì)對(duì)LiBr/H2O、NH3/H2O和R134a/DMF等都是環(huán)保制冷劑。對(duì)于在建筑能耗中占較大比重的中央空調(diào)系統(tǒng)來(lái)說(shuō),采用低品位熱源驅(qū)動(dòng)的吸收式制冷系統(tǒng)對(duì)節(jié)約常規(guī)能源、保護(hù)自然環(huán)境具有十分重要的意義。結(jié)合文獻(xiàn)和手冊(cè)數(shù)據(jù),根據(jù)不同工質(zhì)對(duì)二元溶液的物理性質(zhì),確定了利用Aspen Plus計(jì)算二元工質(zhì)對(duì)溶液熱力學(xué)性質(zhì)的物性方法。溴化鋰水溶液采用ELECNRTL物性方法,氨水溶液及R134a/DMF二元溶液均采用Peng-Rob物性方法,將采用相應(yīng)物性方法計(jì)算的溶液熱力學(xué)性質(zhì)的結(jié)果同文獻(xiàn)中實(shí)驗(yàn)數(shù)據(jù)進(jìn)行了比較,最大誤差分別為2.92%、2.91%和8.8%。 在確定物性方法的基礎(chǔ)上對(duì)三種工質(zhì)對(duì)的循環(huán)特性進(jìn)行了分析,發(fā)現(xiàn)R134a/DMF工質(zhì)對(duì)P-x-y曲線類似于NH3/H2O,在相圖一個(gè)可辨別的DMF氣相組成,需要在循環(huán)中假設(shè)精餾裝置。 借助于Aspen Plus軟件分別搭建了三種工質(zhì)對(duì)循環(huán)的吸收式制冷系統(tǒng),并對(duì)其進(jìn)行了模擬分析。對(duì)溴化鋰吸收式制冷系統(tǒng),分析了發(fā)生溫度、冷凝溫度、稀溶液濃度的變化對(duì)系統(tǒng)的影響；計(jì)算及確定了不同冷凝溫度下系統(tǒng)所需的最小冷卻水量及串并聯(lián)方式,當(dāng)冷凝溫度在42～45℃,冷卻水采用串聯(lián)形式,38-42℃時(shí)采用并聯(lián)的形式：對(duì)氨水吸收式制冷系統(tǒng),分析了回流比的變化及精餾塔塔底溫度對(duì)系統(tǒng)性能的影響,綜合考慮精餾效果以及系統(tǒng)的性能,回流比選擇在0.4～0.6之間是比較合適,放氣范圍在0.065～0.15之間系統(tǒng)COP較高；對(duì)R134a/DMF吸收式制冷系統(tǒng),分析了回流比、R134a在混合溶液的質(zhì)量比及精餾塔底部溫度的變化對(duì)系影響,合理的回流比范圍為0.5～0.7,放氣范圍在0.17～0.39之間系統(tǒng)COP趨于穩(wěn)定較優(yōu)；吸收器中R134a被完全吸收,所需冷卻源的溫度較低,提高吸收器出口溶液的氣相分率可以降低對(duì)冷卻源溫度的要求。 對(duì)比三種工質(zhì)對(duì)的主要參數(shù)發(fā)現(xiàn),對(duì)于發(fā)生溫度可變化范圍,LiBr/H2O工質(zhì)對(duì)最小,僅為6.3℃,對(duì)于COP, NH3/H2O工質(zhì)對(duì)最小；R134a/DlVIF的放氣范圍區(qū)間最大,發(fā)生溫度可變化的范圍最大,為31.36℃,發(fā)生溫度最低為68.8℃,可以適用于一些低溫且溫度波動(dòng)大的熱源,有一定的發(fā)展應(yīng)用前景。 在對(duì)我國(guó)太陽(yáng)能資源及太陽(yáng)能輻射強(qiáng)度與建筑負(fù)荷關(guān)系進(jìn)行分析的基礎(chǔ)上了,分析了太陽(yáng)能集熱器的類型與三種不同工質(zhì)對(duì)所需驅(qū)動(dòng)熱源溫度的匹配性。對(duì)于LiBr/H2O和NH3/H2O吸收式制冷系統(tǒng)采用真空管集熱器比較適合,對(duì)于R134a/DMF吸收式制冷系統(tǒng)由于所需要的發(fā)生溫度較低,大部分工況可以使用低溫平板型集熱器。
[Abstract]:Absorption refrigeration is a kind of refrigeration method which can be driven by low-grade heat sources such as waste heat, solar energy and so on. The commonly used refrigerants are environmental refrigerants such as LiBr-H _ 2O, NH _ 3 / H _ 2O and R134a/DMF. For the central air conditioning system which accounts for a large proportion of building energy consumption, it is very important to adopt absorption refrigeration system driven by low grade heat source to save conventional energy and protect the natural environment. According to the physical properties of binary solutions with different working fluids, a method of calculating the thermodynamic properties of binary solutions by Aspen Plus was established by combining the literature and manual data. The ELECNRTL physical property method is used in lithium bromide aqueous solution, and the Peng-Rob physical property method is used in ammonia water solution and R134a/DMF binary solution. The thermodynamic properties of the solution calculated by the corresponding physical property method are compared with the experimental data in the literature. The maximum error was 2.92% and 8.8%, respectively. Based on the determination of physical properties, the cyclic characteristics of three pairs of working fluids are analyzed. It is found that the P-x-y curve of R134a/DMF is similar to that of NH _ 3 / H _ 2O. In the phase diagram, a discernible DMF gas phase composition needs to be assumed in the cycle distillation unit. With the help of Aspen Plus software, three absorption refrigeration systems with working fluid pair cycle are built and simulated. For the libr absorption refrigeration system, the influence of the temperature, condensation temperature and dilute solution concentration on the system is analyzed, and the minimum cooling water quantity and the series-parallel connection mode are calculated and determined. When the condensing temperature is 42 ~ 45 鈩，

本文編號(hào)：1862921