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西安文理學(xué)院本科畢業(yè)設(shè)計（論文）指導(dǎo)教師評分表
學(xué)生姓名
安劍
學(xué) 號
08102080219
專 業(yè)
機(jī)械設(shè)計制造及其自動化
班 級
08級機(jī)械2班
畢業(yè)設(shè)計（論文）題目
小型冷庫設(shè)計
設(shè)計（論文）起止時間
2012年1月10日至2012年5 月18日
指導(dǎo)教師評語：
建議成績：
指導(dǎo)教師簽名：
年 月 日
西安文理學(xué)院本科畢業(yè)設(shè)計（論文）評閱教師評分表
學(xué)生姓名
安劍
學(xué) 號
08102080219
專 業(yè)
機(jī)械設(shè)計制造及其自動化
班 級
08級機(jī)械2班
畢業(yè)設(shè)計（論文）題目
小型冷庫設(shè)計
設(shè)計（論文）起止時間
2012年1月10日至2012年5 月18日
評閱教師評語：
建議成績：
評閱教師簽名：
年 月 日
附錄
外文文獻(xiàn)
The energy-conservation of freezer, with automaticallying control
1 A present freezer of automatic control current situations
Though the cold storage self-control having been popularized all round, but great majority cold storages putting particular emphasis on is only a safeguard face to face , the energy conservation having increased Wenku picking up the self-adjustment and cold storage measuring and controlling, to entire system relates that under the control of seldom or. Even if another aspect, already getting the all-round universal safeguard, before actual condition in working can't admit of no sanguine, } pins up the cold storage self-control facilities having become "ear of the deaf person" even having become furnishing and decorating decorating front appearance only. The Shanghai cold storage association has done investigation in recent years to Shanghai area ammonia refrigerating system cold storage safeguard and autocontrol condition , concrete conditions has seen that are what form l shows. A spot of should inquire into a data as the leopard has reflected current cold storage self-control general situation
Form what 1 shows a self-control interposes and runs status though the very good cold storage only having 5 tidal current and direction accounting for 9% of the number counting, but it is these cold storages to have represented a nowadays. With the development of electron technology, the self-control component is more and more advanced , changeable procedure controller (PLC) and the PC function are more and more strong , self-control procedure is more and more perfect, system optimization and the energy conservation consciousness are also more and more strong. The cold storage energy conservation and the autocontrol relation are more and more rapid and intense , need the cold storage energy conservation to be ready for and composing much better, do well in and be engaged in better the autocontrol vitally needing right away. Above-mentioned example adopted by five cold storages representing tidal current in the nowadays and advanced level has all got the pretty important effect to realizing cold storage energy conservation.
2 How be ready for cold storage energy conservation autocontrol
Fundamental above-mentioned content starting point is the cold storage taking ammonia as all together style refrigeration working medium refrigerating system , is that refrigeration working medium decentralization, allows all together style , all together style refrigerating system cold storage to have got very big development , whose self-control degree overtops also sometimes the all together style refrigerating system cold storage taking ammonia as refrigeration working medium on behalf of a hydrocarbon with the thick gravy nowadays. Many working mediums are unlike cold storage of system of all kinds extensive use, content having enriched cold storage autocontrol tremendously, application in energy conservation at the same time also has provided the vast scope for one's ability to autocontrol in the cold storage.
2.1 Cold storage energy conservation autocontrol
Cold storage energy conservation autocontrol is energy conservation under the control of procedure establishment and self-control component selecting and using from the content coming to study the autocontrol developing cold storage energy conservation's relates that mainly whom.
The firm, special field designing institute or capable unit as self-control component may assume cold storage energy conservation autocontrol research and develop equally. The firm and the designing institute make a contribution to some extent without exception already by now within that field. Cold storage energy conservation autocontrol can be developed exploitation commonly by firm and designing institute best (not bad firm give first place to, the designing institute coordinates) , perfects in the process of putting into effect using an unit the new product getting into form and grinding unceasingly to get rich.
2.2 Energy conservation autocontrol specific items design prepares a cold storage putting composition into practice.
That a specific items energy conservation autocontrol's puts process into practice sometimes is that the purpose checking K amendment , reaching energy conservation until according with design demand by designing , assembling debugging , pilot run , effect is extremely. While the project requires that content is changed into a ratio to some extent, may revise K at any time satisfying a request.
The cold storage energy conservation sometimes requires that the advanced refrigeration switches over to prepare , right system mates , effective the words emergency measure and strict operation manage to manage to be put into effect, be requiring that the refrigeration technician goes ahead in the basis optimizing refrigeration process design right now, know well that energy conservation needs , be tied in wedlock this project characteristic , the flow chart designing out entire cold storage energy conservation autocontrol. Ability accomplishes whose electricity self-control design according to the self-control flow chart , the electricity self-control technician , being able to wield whose professional knowledge at the same time, makes self-control technological process be simplification and an optimization more. Cold storage energy conservation is a cold storage autocontrol important component , all cold storage autocontrol is composed of refrigeration and electricity two parts content without exception , K makes cold storage energy conservation be carried out to the letter only when ability makes cold storage autocontrol come into effect in the field of two under technician's making joint efforts.
3 Cold storage energy conservation autocontrol pilot run is also one very important ring , echoes the usage unit and the special field firm in the pilot run keeping close connection , uses an unit to discuss working effect , deliberates amendment measure with special field firm and.
Energy conservation is one of cold storage autocontrol purpose.
3.1 Adjusts storehouse temperature adjustment in the past about that the storehouse temperature and the evaporation temperature adjust the parametric storehouse of
3.1.1 Storehouse temperature control
Multiple spots temperature temperature giving first place to dyadic adjustment of place, correct evaporate the temperature not sometimes doing adjustment , very difficult to reach good energy conservation effect.
The ideal storehouse temperature control mode is that wind and their air-out temperature is entering parameter with the storehouse mean temperature , the air cooler moving forward , works out appropriate under the control of procedure , measures by the fact that PLC is in progress. So-called Wenku adjusts the request being able to reach energy conservation , also can satisfy the need that some storehouse high-accuracy temperature adjusts, self own but the accuracy reaching 0.250 C requires that energy conservation makes an appointment with 10% at present.
3.1.2 Regard to relatively evaporate temperature higher cold right away be in no energy conservation operation state
Ps stop being unlike the diversity evaporates because K couplet operation can only work under evaporating the temperature with a with a systematic refrigeration compression engine evaporating the cold room of temperature temperature cold if K couplet work, with regard to relatively evaporate temperature higher cold right away be in no energy conservation operation state, should cold hot load increasingly be promoted to a higher post increasingly no energy conservation. Ought to try one's best to avoid this condition appearing. One machine reviews the cold storage method of work pair in freon refrigerating system , add the back pressure valve on time of high temperature warehouse air tube , add single check valve on time of low temperature warehouse air tube, be representative block of wood energy conservation method of work, do not respond to encourage but suitable abolish.
3.1.3 Unexpected turn of events evaporates temperature adjustment
Some one work state lower if evaporate temperature can use storehouse hot load and refrigerating system refrigerating output be parameter be in progress adjustment, then now that can reach energy conservation purpose can make energy adjustment be more rational. The sort Er Yan , refrigerating system evaporation implement and refrigeration compression engine equipment can satisfy maximal load need basically all. Load falls off but the refrigerating output can not make corresponding adjustment in time if the cold room is hot, the refrigerating output and hot load being that the refrigerating system evaporation temperature will may act in responses reduces , uses a compression engine reach a new balance burning. The lessening evaporating the temperature has increased but the refrigerating output evaporating an implement conversely but , has faced the hot load that self own cuts down taking form surely frequently opening the consequence staying. Evaporate temperature 10 C per change, electric energy about 3 ~ 5% acting in responses adding or subtracting. Be energy conservation on making system burn in another ideal balance of } if raising the evaporation temperature in time,have avoided freely not having achieved not only, having decreased by the refrigeration compression engine's frequently starts , is the energy conservation measure achieving two things at one stroke. Not changeable fundamental refrigerant rate of flow rate of flow evaporating an implement adjusts.
3.1.4 Changeable rate
Changeable rate of flow adjustment ammonia in the past refrigerating system; Freon system evaporates the implement refrigerant rate of flow , great majority achieve simple proportion measures. The air cooler air mass flow great majority do not measure or speed and the electric fan platform number measure only when two. This two kinds parametric rate of flow adjustment all are cold the adjustment assigning the equipment refrigerating output and storehouse temperature direct relevance , one of the content being also that the cold storage energy conservation self-control responds to in taking seriously with the storehouse.
3.1.5 Fetch the warehouse taken height
Sets up right under the control of accuracy and adds the storehouse temperature setting up the commodity and different storage period controlling the different storehouse , different stock out of gauge having no equal to and their under the control of accuracy request. Set off from the energy conservation angle, the storehouse temperature ought to take height not choosing low , the mild high-accuracy controlling accuracy ought to fetch the warehouse taken height , insisted to run after face to face unnecessarily low low controls as long as not affecting the commodity quality.
To the cold room of many } storehouse temperature under the control of, except original storehouse temperature setting value, suitable add set up Kuwen transfinite controlling value. This pair of factors storehouse temperature adjusts deflect but premature bringing into service being able to achieve when refrigerating system needs bringing into service , incapable because of } pins up the storehouse temperature; Can not make cold according to reality that time at intervals, refrigerating system stops working untimely Ding , fully utilizes now having energy K avoid equipment or systematic frequently open Ding.
3.1.6 Set up avoiding meeting high o peration
Interpose avoid meeting high o operation under the control of electric power short-supplied be the universal phenomenon that current all parts of the country there exists in everywhere, huge bad especially heavy electric power of power consumption o grain is short-supplied , the electric charge o grain price differences puts into effect in a lot of city and price differences play big as early as successive steps for this purpose. Under the premise not affecting commodity mass, the cold storage is set up avoiding meeting high o peration , beneficial to the electrified wire netting cuts o repair a valley , help overall situation energy conservation on macroscopic view; Microcosmic Er Yan operation also beneficial toreducing a cold storage cost.
3.2 Cold room relative humidities adjust cold room relative humidity adjustment
Cold room relative humidities adjust cold room relative humidity adjustment and the temperatureadjusts the method similarity repeating description unnecessarily. But in general cold room relative humidity is in 85 ~ the relative humidity that the also a little bit cold room demands is lower than or the relative humidity higher than the be 98%, but some crops of relative humidity kind of quality warehouse being range , for instance some gases turn to obj1 = " 位" exchange the warehouse request demands 45% to be 40 ~ between 95%. During the period of high relative humidity adjustment and low relative humidity adjustment, Youyin attaches importance to energy conservation measure.
3.2.1 High relative humidities adjust the adjustment
High relative humidities adjust the adjustment demanding the cold room to high relative humidity , are going try one's best to reduce the logarithm averages difference in temperature (2 advisable K) between the refrigerant temperature and the storehouse temperature, return refrigerating system back when being necessary but adopt to be loaded with the cold agent first; May adopt air defrosting K besides with defrosting water restoring to the storehouse. That this two measure is given by autocontrol being put into effect, is effective energy conservation method , the domestic trade headquarter has not been 20,000 tons of Long Kou City gas that the research institute designs obj1 exchange a warehouse being a very good example of one 17 }.
3.2.2 Low relative humidities adjust the adjustment
Low relative humidities adjust the adjustment demanding the cold room to low relative humidity , controlling also should be ready for two aspect mainly. One is on the basis selecting and using dehumidification method and dehumidification machine stopping bringing quantity of heat into cold room to the full, hot few cold p rooms load controlling good dehumidification while procedure, reaching the relative humidity request. It's two is to avoid air current organizing the wet load controlling fever of taking now and then entering unnecessary outside; Once had the wet low one } low temperature crops kind of quality warehouse, wet load roughly accounts for about35% of plain meter { load from invading the heat within being put in storage outside.
3.3 Measures about providing liquid way
Direct swelling is for liquid's expanding directly to be for liquid's being that great majority thick gravies pin up the confession liquid method that ammonia system adopts on behalf of hydrocarbon (include freon) system and }. This provides liquid method with adopt the heating power expansion valve to provide liquid in the past basically , self problem, has no way to realize the energy conservation purpose since choosing the type , adjustment and product. Electron expansion valve appearing measures combining with selecting parametric Kuwen of temperature much , can realize energy conservation operation fairly good, sort but energy conservation 10%. But the thick gravy generation hydrocarbon refrigerating system heating power expansion valve product already be commensurate to maturity and still have the special-purpose PLC Kuwen controller, for a variety of reasons, adopt extension , wait for to increase energy not yet commonly in cold storage refrigerating system. Working hot shot degree of ammonia refrigerating system evaporation implement is not big , degree of difficulty is under the control of relatively bigger , there is no at present still mature ammonia using electron to expand ? ? valve product. The system
中文翻譯
冷庫節(jié)能與自動控制
1 當(dāng)前冷庫自控現(xiàn)狀
冷庫自控雖然得到了全面普及，然而大多數(shù)冷庫的側(cè)重面只是安全保護(hù)，或者還增加了溫庫撿測和控制，對于全系統(tǒng)的自動調(diào)節(jié)和冷庫的節(jié)能控制還很少涉及。另一方面，即便已得到全面普及的安全保護(hù)，在實際運行中的情況也不容樂觀，個別冷庫的自控設(shè)施甚至成了“聾子的耳朵”只成了裝飾門面的擺設(shè)。近年來上海冷藏庫協(xié)會對上海地區(qū)氨制冷系統(tǒng)冷庫的安全保護(hù)和自動控制情況作了調(diào)查，具體情況見表l所示。該調(diào)查數(shù)據(jù)作為豹之一斑反映了當(dāng)前冷庫自控的概況。
自控設(shè)置和運行狀況很好的冷庫雖然只有5座，占統(tǒng)計數(shù)的9％，然而就是這些冷庫代表了當(dāng)今的潮流和方向。隨著電子技術(shù)的發(fā)展，自控元件越來越先進(jìn)、可變程序控制器（PLC）和微機(jī)的功能越來越強(qiáng)、自控程序越來越完善，系統(tǒng)優(yōu)化和節(jié)能的意識也越來越強(qiáng)。冷庫的節(jié)能和自動控制的關(guān)系越來越緊密，要把冷庫的節(jié)能做好和做得更好，就必需把自動控制搞好和搞得更好。上述五座代表當(dāng)今潮流和先進(jìn)水平的冷庫所采用的以下幾項自控內(nèi)容的實例對實現(xiàn)冷庫節(jié)能都起了相當(dāng)重要的作用。
2 如何做好冷庫節(jié)能的自動控制
上述內(nèi)容的基本出發(fā)點是以氨為制冷工質(zhì)的集中式制冷系統(tǒng)的冷庫，當(dāng)今以鹵代烴為制冷工質(zhì)的分散式、準(zhǔn)集中式、集中式制冷系統(tǒng)的冷庫得到了很大的發(fā)展，其自控程度也往往高于以氨為制冷工質(zhì)的集中式制冷系統(tǒng)冷庫。多工質(zhì)不同系統(tǒng)各類冷庫的廣泛應(yīng)用，極大地豐富了冷庫自動控制的內(nèi)容，同時也為自動控制在冷庫節(jié)能中的應(yīng)用提供了廣闊的用武之地。
2.1 冷庫節(jié)能的自動控制由誰來研究開發(fā)
冷庫節(jié)能的自動控制主要涉及的內(nèi)容是節(jié)能控制程序的編制和自控元器件的選用。作為自控元器件的廠商、專業(yè)設(shè)計院或有能力的使用單位均可擔(dān)當(dāng)冷庫節(jié)能自動控制的研究和開發(fā)。到目前為止廠商和設(shè)計院在該領(lǐng)域內(nèi)均已有所建樹。
冷庫節(jié)能的自動控制最好能由廠商和設(shè)計院共同研制開發(fā)（可以廠商為主，設(shè)計院配合），在使用單位的實施過程中完善定型并不斷研發(fā)新產(chǎn)品。
2.2 冷庫節(jié)能自動控制具體項目的設(shè)計和實施配合
一個具體項目節(jié)能自動控制的實施過程往往是通過設(shè)計、安裝調(diào)試、試運行、效果考核並修正，直至符合設(shè)計要求達(dá)到節(jié)能目的為至。當(dāng)項目要求內(nèi)容有所變比時，可隨時修改並滿足要求。
冷庫的節(jié)能往往需要通先進(jìn)的制冷改備、合適的系統(tǒng)匹配、靈話的應(yīng)變措施和嚴(yán)格的運行管理得以實施，這就需要制冷技術(shù)人員在優(yōu)化制冷工藝設(shè)計的基礎(chǔ)上，熟悉節(jié)能需要、結(jié)合本項目特點，設(shè)計出完整的冷庫節(jié)能自動控制流程圖。根據(jù)自控流程圖，電氣自控技術(shù)人員才能完成其電氣自控設(shè)計，同時還能運用其專業(yè)知識，使自控流程更為簡化和優(yōu)化。冷庫節(jié)能是冷庫自動控制重要組成部分，凡冷庫自動控制均由制冷和電氣兩部分內(nèi)容組成，只有在兩方面技術(shù)人員的共同努力下才能使冷庫自動控制行之有效並使冷庫節(jié)能落到實處。
冷庫節(jié)能自動控制的試運行也是十分重要的一環(huán),在試運行中應(yīng)和使用單位和專業(yè)廠商保持密切聯(lián)系，與使用單位探討運行效果，與專業(yè)廠商商討修正措施。
3 冷庫節(jié)能自動控制的若干做法和設(shè)想
節(jié)能是冷庫自動控制的目的之一。
3.1 關(guān)于庫房溫度和蒸發(fā)溫度調(diào)節(jié)
3.1.1 多點溫度參數(shù)的庫房溫度調(diào)節(jié)
以往庫房溫度調(diào)節(jié)以位式調(diào)節(jié)為主，對蒸發(fā)溫度往往不作調(diào)節(jié)，很難達(dá)到好的節(jié)能效果。
庫房溫度理想的控制方式是以庫房的平均溫度、冷風(fēng)機(jī)的進(jìn)風(fēng)及其出風(fēng)溫度為輸入?yún)?shù)，編制適當(dāng)?shù)目刂瞥绦颍ㄟ^PLC進(jìn)行調(diào)節(jié)。如此溫庫調(diào)節(jié)可以達(dá)到節(jié)能的要求，也能滿足某些庫房高精度溫度調(diào)節(jié)的需要，目前己可達(dá)到0.250C的精度要求節(jié)能約10％。
3.1.2 減少不同蒸發(fā)溫度冷間的並聯(lián)運行
由于同一系統(tǒng)的制冷壓縮機(jī)只能在同一個蒸發(fā)溫度下運行，所以不同蒸發(fā)溫度的冷間如果並聯(lián)運行，對于相對蒸發(fā)溫度較高的冷間就處于不節(jié)能的運行狀態(tài)，該冷間熱負(fù)荷越高就越不節(jié)能。應(yīng)當(dāng)盡量避免這種情況的出現(xiàn)。氟利昂制冷系統(tǒng)中一機(jī)雙溫冷庫的做法，在高溫庫回氣管上加背壓閥，在低溫庫回氣管上加單向閥，是不節(jié)能的典型做法，不應(yīng)提倡而宜廢止。
3.1.3 變蒸發(fā)溫度調(diào)節(jié)
在某一運行狀態(tài)下如果蒸發(fā)溫度能以庫房熱負(fù)荷以及制冷系統(tǒng)制冷量為參數(shù)進(jìn)行調(diào)節(jié)，則既能達(dá)到節(jié)能的目的還能使能量調(diào)節(jié)更為合理。一般而言，制冷系統(tǒng)蒸發(fā)器和制冷壓縮機(jī)的配備基本都能滿足最高負(fù)荷的需要。如果冷間熱負(fù)荷減少而制冷量不能及時作出相應(yīng)調(diào)節(jié)，則制冷系統(tǒng)的蒸發(fā)溫度將會相應(yīng)降低，使壓縮機(jī)的制冷量與熱負(fù)荷達(dá)到一個新的平衡點。而蒸發(fā)溫度的降低反過來卻增加了蒸發(fā)器的制冷量，面對己減少的熱負(fù)荷必然形成頻繁啟停的后果。蒸發(fā)溫度每變化10C，相應(yīng)增減的電能約3～5％。如果及時調(diào)高蒸發(fā)溫度，使系統(tǒng)在另一亇理想的平衡點上，則不但避免了浪弗、做到了節(jié)能，還減少了制冷壓縮機(jī)的頻繁起動，是一舉兩得的節(jié)能措施。
3.1.4 變流量調(diào)節(jié)
以往氨制冷系統(tǒng)蒸發(fā)器的制冷劑流量基本沒有變流量調(diào)節(jié)；氟利昂系統(tǒng)蒸發(fā)器的制冷劑流量，大多數(shù)只做到簡單的比例調(diào)節(jié)。空氣冷卻器的空氣流量大多數(shù)沒有調(diào)節(jié)或者只有雙速及風(fēng)扇臺數(shù)調(diào)節(jié)。這兩種流量參數(shù)的調(diào)節(jié)都是與庫房冷分配設(shè)備制冷量以及庫房溫度直接相關(guān)的調(diào)節(jié)，也是冷庫節(jié)能自控應(yīng)于重視的內(nèi)容之一。
3.1.5 設(shè)定合適的控制精度和加設(shè)超限控制
不同的庫房、不同的庫存商品和不同的貯存期都有不同的庫房溫度及其控制精度要求。從節(jié)能的角度出發(fā)，只要不影響商品的品質(zhì)，庫房溫度宜取高不取低、控制精度宜取低不取高，不必偏面追求過低的庫溫和高精度控制。
對于多亇冷間的庫房溫度控制，除了原有的庫房溫度設(shè)定值之外，宜加設(shè)庫溫超限控制值。這種雙因素的庫房溫度調(diào)節(jié)能做到制冷系統(tǒng)需要投入運行時，不會因為亇別庫房溫度的偏離而過早投入運行；還可以根據(jù)當(dāng)時的實際情況不使冷間或制冷系統(tǒng)過早地仃止運行，充分利用現(xiàn)有能量並避免設(shè)備或系統(tǒng)的頻繁啟停。
3.1.6 設(shè)置避高峯運行控制
電力緊缺是當(dāng)前全國各地存在的普遍現(xiàn)象，用電峯谷的巨差更加重了電力緊缺，為此電費的峯谷差價在許多城市實行而且價差還在逐步拉大。在不影響商品質(zhì)量的前提下，冷庫設(shè)置避高峯運行，有利于電網(wǎng)削峯補(bǔ)谷，宏觀上幫助全局節(jié)能；微觀而言也有利于降低冷庫的運行成本。
3.2 冷間相對濕度調(diào)節(jié)
冷間相對濕度的調(diào)節(jié)與溫度調(diào)節(jié)方法的相似之處不必重復(fù)敘述。一般冷間的相對濕度在85～95％之間，但也有一些冷間要求的相對濕度低于或高于該范圍，例如有些氣調(diào)庫要求的相對濕度是98％、而有些農(nóng)作物種質(zhì)庫的相對濕度要求是40～45％。在高相對濕度調(diào)節(jié)和低相對濕度調(diào)節(jié)時尤因注重節(jié)能措施。
3.2.1 高相對濕度調(diào)節(jié)
對于高相對濕度要求冷間的調(diào)節(jié)，首先要盡量降低制冷劑溫度和庫房溫度之間的對數(shù)平均溫差（可取2K），有必要時還可采用載冷劑間接制冷系統(tǒng)；此外還可采用空氣融霜並把融霜水還原給庫房。這兩項措施通過自動控制予以實施，是行之有效的節(jié)能方法，國內(nèi)貿(mào)易部沒計研究院設(shè)計的龍口二萬噸氣調(diào)庫就是一亇很好的例證。
3.2.2 低相對濕度調(diào)節(jié)
對于低相對濕度要求冷間的調(diào)節(jié)，主要也應(yīng)做好兩方面的控制。其一是在選用盡量少帶熱量進(jìn)冷間的去濕方法和去濕機(jī)的基礎(chǔ)上，控制好去濕程序，在達(dá)到相對濕度要求的同時減少冷間的熱負(fù)荷。其二是避免氣流組織控制時帶入不必要的室外熱濕負(fù)荷；曾經(jīng)有一亇低溫低濕的農(nóng)作物種質(zhì)庫，由室外侵入庫內(nèi)的熱濕負(fù)荷約占原計祘負(fù)荷的35％左右。
3.3 關(guān)于供液方式調(diào)節(jié)
直接膨脹供液是大多數(shù)鹵代烴（包括氟利昂）系統(tǒng)和個別氨系統(tǒng)采用的供液方法。這種供液方法以往基本采用熱力膨脹閥供液，由于選型、調(diào)節(jié)以及產(chǎn)品本身的問題，無法實現(xiàn)節(jié)能的目的。電子膨脹閥的出現(xiàn)結(jié)合多點溫度參數(shù)的庫溫調(diào)節(jié)，可以較好地實現(xiàn)節(jié)能運行，一般可節(jié)能10％。鹵代烴制冷系統(tǒng)的熱力膨脹閥產(chǎn)品已相當(dāng)成熟而且還有專用的PLC庫溫控制器，但由于種種原因在冷庫制冷系統(tǒng)中尚未普遍采用，有待加力推廣。氨制冷系統(tǒng)蒸發(fā)器運行的過熱度不大，控制難度相對較大，目前尚無成熟的氨用電子膨脹閥產(chǎn)品。
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