冰蓄冷低溫送風空調(diào)系統(tǒng)損因素分析

周學麗，李念平，鄒杰

(1.湖南大學 土木工程學院 長沙 410082；2.廣州黃巖機電科技有限公司 廣州 510000)

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周學麗1，李念平1，鄒杰2

(1.湖南大學 土木工程學院 長沙 410082；2.廣州黃巖機電科技有限公司 廣州 510000)

摘要：低溫送風空調(diào)系統(tǒng)引進新型冰蓄冷設備，采用正丁烷作為制冷劑，制冷劑與水直接接觸，換熱更強烈且穩(wěn)定。為了研究該系統(tǒng)相應損因素條件下的節(jié)能薄弱環(huán)節(jié)，實現(xiàn)系統(tǒng)性能優(yōu)化，基于該系統(tǒng)及各表冷器分析模型，分析了熱濕比、新風比、送風溫差等損因素對系統(tǒng)效率和各表冷器損率的影響。結果表明：當熱濕比變化時，處理二次混風的表冷器損率隨之呈正比變化，其他表冷器損率及系統(tǒng)效率隨之呈反比變化；當新風比變化時，處理新風的兩級表冷器損率隨之呈正比變化，其他表冷器損率及系統(tǒng)效率隨之呈反比變化；當送風溫差變化時，處理一次回風的表冷器損率隨之呈正比變化，其他表冷器損率及系統(tǒng)效率隨之呈反比變化。

關鍵詞：低溫送風空調(diào)系統(tǒng)；分析模型；損率；效率；冰蓄冷

自從20世紀推廣使用冰蓄冷技術以來[1]，冰蓄冷技術以“移峰填谷”的優(yōu)勢，成為暖通空調(diào)領域炙手可熱的“寵兒”[1-2]。傳統(tǒng)的冰蓄冷設備采用乙烯乙二醇溶液為制冷劑，制冷劑不與冰水直接接觸，傳熱熱阻高，傳熱效率低；為了滿足制冷要求，需要配備大面積換熱管，運行效率較低[3]。鄒杰[3]研發(fā)了一種新型動態(tài)冰蓄冷設備，采用正丁烷作為制冷劑，制冷劑與冰水直接接觸，制冰過程中制冷劑帶走熱量將冷水制成冰，融冰過程中依靠冰融化向空調(diào)系統(tǒng)供冷；為了更好地將水與制冷劑混合，在冰蓄冷設備中設置移動床等傳動裝置，換熱更加強烈，運行效率更高，控制更加可靠[4]。筆者介紹的低溫送風空調(diào)系統(tǒng)引進該新型動態(tài)冰蓄冷設備，夜晚利用冷水機組制冰，白天利用冷水機組和冰蓄冷設備分別向空調(diào)機組提供7/12 ℃和0/7 ℃的冷凍水，高效實現(xiàn)低溫送風和負荷轉(zhuǎn)移[5]。但是相關研究發(fā)現(xiàn)該系統(tǒng)能量利用效率受到諸如熱濕比、新風比、送風溫差等運行參數(shù)的影響，因此，筆者基于能量利用效率進行研究，為優(yōu)化系統(tǒng)性能及提高系統(tǒng)節(jié)能性奠定理論基礎。

(1)

式中：T0為環(huán)境空氣溫度，K；Ta為進出口對數(shù)平均溫度，K。

(2)

(3)

(4)

(5)

冰蓄冷低溫送風空調(diào)系統(tǒng)空氣處理流程如圖1所示[5]，空氣處理過程焓濕圖如圖2所示[5]，由圖1和圖2可知，表冷器1是處理新風(狀態(tài)點1)的一級表冷器，冷凍水供回水溫度為7/12 ℃，由冷水機組提供；處理新風的二級表冷器是表冷器2，由冰蓄冷系統(tǒng)提供冷凍水，供回水溫度為0/7 ℃，它能夠?qū)⒈砝淦?處理后的新風(狀態(tài)點1′)處理到溫度T=3.8 ℃，相對濕度φ=95%，含濕量d=4.76 g/kg的低溫風(狀態(tài)點1″)；一次回風(狀態(tài)點2)由變頻風機控制流量，由表冷器3(供回水溫度為0/7 ℃)處理到溫度T=3.8 ℃，相對濕度φ=95%，含濕量d=4.76 g/kg的低溫風(狀態(tài)點2′)，最終與兩級表冷處理過的新風混合為一次混風，一次混風和二次回風(狀態(tài)點2″)混合為二次混風(狀態(tài)點3)；二次混風由表冷器4(供回水溫度為7/12 ℃)在干工況下處理到達送風狀態(tài)(狀態(tài)點4)，最終由送風機將送風(狀態(tài)點5)送入室內(nèi)用于消除房間熱濕負荷。

圖1　冰蓄冷低溫送風空調(diào)系統(tǒng)空氣處理流程圖Fig.1　Flow diagram of the ice storage system with cold

圖2　冰蓄冷低溫送風空調(diào)系統(tǒng)空氣處理焓濕圖fig.2　Air conditioning process of the ice storage system with cold air

(6)

(7)

(8)

(9)

(10)

(11)

圖3　各設備損失率隨熱濕比變化曲線Fig.3　Different exergy loss rate values of the surface air coolers under different heat and humidity

圖4　系統(tǒng)損失和效率隨熱濕比變化曲線Fig.4　Different exergy loss values and exergy efficiency values of the system under different heat and humidity

圖5　各設備損失率隨新風比變化曲線Fig.5　Different exergy loss rate values of the surface air coolers under different fresh air

圖6　系統(tǒng)損失和效率隨新風比變化曲線Fig.6　Different exergy loss values and exergy efficiency values of the system under different fresh air ratio

圖7　各設備損失率隨送風溫差變化曲線Fig.7　Different exergy loss rate values of the surface coolers under different temperature difference between supply air and indoor

圖8　系統(tǒng)損失和效率隨送風溫差變化曲線Fig.8　Different exergy loss values and exergy efficiency values of the system under different temperature difference between supply air and indoor

4結論與展望

5)筆者的分析計算依據(jù)來源于冰蓄冷低溫送風空調(diào)系統(tǒng)設計工況，對于非設計工況的系統(tǒng)性能優(yōu)化具有指導意義，而與非設計工況的對比研究有待開展。

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(編輯胡英奎)

Analysis on exergy loss factors of a novel ice storage system with cold air distribution

Zhou Xueli1, Li Nianping1, Zou Jie2

(1.College of Civil Engineering, Hunan University, Changsha 410082, P. R. China;2.Guangzhou Huangyan Mechanical and Electrical Technology Co., Guangzhou 510000, P. R. China)

Abstract:An exergy analysis model was developed for a novel ice storage system with cold air distribution and its main surface air coolers. Based on this model, the influence of heat and humidity ratio, fresh air ratio and temperature difference between supply air and indoor air on the exergy efficiency of the system and the exergy loss rate of its surface air coolers was studied. Finally the important parameters for system optimization were identified. The simulation results show that the exergy loss rate of the surface air cooler for secondary mixed air is positively proportional to the variation of heat and humidity ratio, while it is inverse for the other; the exergy loss rate of the surface air coolers for fresh air is positively proportional to the variation of fresh air ratio, while it is opposite for the other; the exergy loss rate of the surface air cooler for primary mixed air is positively proportional to the variation of temperature difference between supply air and indoor air, while it is inverse for the other.

Keywords:cold air distribution system; exergy analysis model; exergy loss rate; exergy efficiency; ice storage.

doi:10.11835/j.issn.1674-4764.2016.02.018

收稿日期：2015-08-12

基金項目：國家自然科學基金(51578220)

作者簡介：周學麗(1991-)，女，主要從事建筑節(jié)能技術研究，(E-mail)18229945449@163.com。

中圖分類號：TU831.3

文獻標志碼：A

文章編號：1674-4764(2016)02-0132-06

李念平(通信作者)，男，教授，博士生導師，(E-mail)linianping@126.com。

Received:2015-08-12

Foundation item：National Natural Science Foundation of China (No. 51578220)

Author brief：Zhou Xueli (1991- ), main research interest:building energy-saving technology,(E-mail) 18229945449@163.com.

Li Nianping(corresponding author), professor, doctor supervisor， (E-mail) linianping@126.com.