【正文】 圖 給出了往復(fù)式、螺桿式、旋渦式、帶葉片控制的離心式制冷機(jī)組、壓縮機(jī)頻繁啟動(dòng)的制冷機(jī)組在滿(mǎn)負(fù)荷時(shí)的百分比下相應(yīng)的效率（用 kw/ton 表示）。而往復(fù)式是這四種類(lèi)型中效率最低的。制冷機(jī)的效率通常用輸入功（用 kw表示）與制冷量（用 tons 表示）的比值表示。 蒸汽壓縮式制冷機(jī) 四種電啟動(dòng)的蒸汽壓縮式制冷機(jī)組的名義制冷量范圍。 在建筑中所使用的制冷機(jī)組類(lèi)型根據(jù)應(yīng)用場(chǎng)所來(lái)確定。 制冷機(jī)組名義制冷量為 30～ 18000kw（ 8～ 5100tons）。接著，水用水泵打到冷卻塔中，水通過(guò)蒸發(fā)而降溫。在換熱器中，空氣被冷凍水冷卻和加濕。吸收式制冷機(jī)在吸收循環(huán)中利用熱能（典型的是來(lái)自蒸汽或燃料燃燒）并利用氨－水或水－鋰溴化物制得冷凍水。而且，由于制冷機(jī)組通常安裝在較大的建筑中，在同一年里，制冷機(jī)組冷卻了多于 28％的商用建筑的地板空間（ DOE， 1998）。人們通常認(rèn)為碳化氫制冷劑易燃且比較危險(xiǎn)，但它在傳統(tǒng)的壓縮機(jī)中和有的工業(yè)設(shè)備中都可以被使用。使用 R410A的系統(tǒng)運(yùn)作中，壓力大約比 R22高 50% (表 )；因此， R410A不能夠用于當(dāng)作速凍制冷劑來(lái)替代 R22。 2020年之后， R22不允許生產(chǎn) (環(huán)保署 ,1993b)。然而， R123有 B1安全等級(jí)，這就意謂它有一個(gè)比較低的毒性而勝于 R134a，如果一個(gè)使用 R123冷卻設(shè)備在一 棟建筑物中被用，當(dāng)使用這些或任何其他有毒的或易燃的制冷劑時(shí)候，標(biāo)準(zhǔn) 15(ASHRAE,1992) 提供安全預(yù)防的指導(dǎo)方針。在 A1中的制冷劑通常用在建筑空調(diào)設(shè)備方面的，包括 R11， R12， R22，R134a,和 R410A。 F)，可以認(rèn)為接近 azeotropic混合制冷劑。 F), 產(chǎn)生了 7176。這種現(xiàn)象被稱(chēng)溫度的移動(dòng)，在大氣壓力下， R407 C的沸點(diǎn) (沸騰 )是 – 44 176。 空調(diào)的制冷能力常用冷噸或千瓦 (千瓦 ) 來(lái)表示，冷噸是一個(gè)度量單位，它與制冰廠在 24小時(shí)內(nèi)使 1噸 (907 公斤 )的水結(jié)冰的能力有關(guān)，其值是 (12,000 Btu/hr)，空調(diào)的冷卻能力不要和產(chǎn)生冷量所需的電能相互混淆。蒸汽的形成要以一定的足夠速度被壓縮機(jī)排出以維持在蒸發(fā)器中低壓和保持循環(huán)進(jìn)行。 冷凝器是一個(gè)熱交換器，用于將制冷劑的熱量傳遞到冷卻介質(zhì)中，制冷劑進(jìn)入冷凝器變成過(guò)冷液體，用于冷凝器中的典型冷卻介質(zhì)是空氣和水，大多數(shù)住宅建筑的冷凝器中使用空氣作為冷卻介質(zhì)，而大型系統(tǒng)的冷凝器中采用水作為冷卻介質(zhì)。 蒸汽壓縮循環(huán) 雖然空調(diào)系統(tǒng)應(yīng)用在建筑物中有較大的尺寸和多樣性 ,大多數(shù)的系統(tǒng)利用蒸汽壓縮循環(huán)來(lái)制取需要的冷量和除濕，這個(gè)循環(huán)也用于制冷和冰凍食物和汽車(chē)的空調(diào)，在 1834年，一個(gè)名叫 帕金斯 的人在倫敦 獲得了機(jī)械制冷系統(tǒng)的第一專(zhuān)利權(quán)，在 1857年，詹姆士和 賽博 生產(chǎn)出第一個(gè)有活力的商業(yè)系統(tǒng)，除了蒸汽壓縮循環(huán)之外 , 有兩種不常用的制冷方法在建筑物中被應(yīng)用 : 吸收式循環(huán)和蒸發(fā)式冷卻，這些將在后面的章節(jié)中講到。 商業(yè)的建筑物從比較大的多層的辦公大樓到街角的便利商店，占地面積和類(lèi)型差別很大，因此應(yīng)用于這類(lèi)建筑的設(shè)備類(lèi)型比較多樣，對(duì)于比較大型的建筑物，空調(diào)設(shè)備設(shè)計(jì)是總系統(tǒng)設(shè)計(jì)的一部分，這部分包括如下項(xiàng)目：例如一個(gè)管道系統(tǒng)設(shè)計(jì)，空 氣分配系統(tǒng)設(shè)計(jì)，和冷卻塔設(shè)計(jì)等。在 1970 年的美國(guó)， 36% 的住宅不是全空氣調(diào)節(jié)就是利用一個(gè)房間空調(diào)器冷卻；到 1997年，這一數(shù)字達(dá)到了 77%，在那年作的第一次市場(chǎng)調(diào)查表明，在美國(guó)有超過(guò)一半的住宅安裝了中央空調(diào) (人口普查局 , 1999)。F). The chilled water is then distributed to watertoair heat exchangers spread throughout the facility. In these heat exchangers, air is cooled and dehumidified by the cold water. During the process, the chilled water increases in temperature and must be returned to the chiller(s). The chillers are watercooled chillers. Water is circulated through the condenser of each chiller where it absorbs heat energy rejected from the high pressure refrigerant. The water is then pumped to a cooling tower where the water is cooled through an evaporation process. Cooling towers are described in a later section. Chillers can also be air cooled. In this configuration, the condenserwould be a refrigeranttoair heat exchanger with air absorbing the heat energy rejected by the high pressure refrigerant. Chillers nominally range in capacities from 30 to 18,000 kW (8 to 5100 ton). Most chillers sold in the . are electric and utilize vapor pression refrigeration to produce chilled water. Compressors for these systems are either reciprocating, screw, scroll, or centrifugal in design. A small number of centrifugal chillers are sold that use either an internal bustion engine or steam drive instead of an electric motor to drive the pressor. The type of chiller used in a building depends on the application. For large office buildings or in chiller plants serving multiple buildings, centrifugal pressors are often used. In applications under 1000 kW (280 tons) cooling capacities, reciprocating or screw chillers may be more appropriate. In smaller applications, below 100 kW (30 tons), reciprocating or scroll chillers are typically used. Vapor Compression Chillers The nominal capacity ranges for the four types of electrically driven vapor pression 7 chillers. Each chiller derives its name from the type of pressor used in the chiller. The systems range in capacities from the smallest scroll (30 kW。C, 10176。C (–35176。F) can be used to reduce costs for space heating. Capacities of air conditioning are often expressed in either tons or kilowatts (kW) of cooling. The ton is a unit of measure related to the ability of an ice plant to freeze one short ton (907 kg) of ice in 24 hr. Its value is kW (12,000 Btu/hr). The kW of thermal cooling capacity produced by the air conditioner must not be confused with the amount of electrical power (also expressed in kW) required to produce the cooling effect. Refrigerants Use and Selection Up until the mid1980s, refrigerant selection was not an issue in most building air conditioning applications because there were no regulations on the use of refrigerants. Many of the refrigerants historically used for building air conditioning applications have been chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). Most of these refrigerants are nontoxic and nonflammable. However, recent . federal regulations (EPA 1993a。英文 文獻(xiàn) Air Conditioning Systems Air conditioning has rapidly grown over the past 50 years, from a luxury to a standard system included in most residential and mercial buildings. In 1970, 36% of residences in the . were either fully air conditioned or utilized a room air conditioner for cooling (Blue, et al., 1979). By 1997, this number had more than doubled to 77%, and that year also marked the first time that over half (%) of residences in the . had central air conditioners (Census Bureau, 1999). An estimated 83% of all new homes constructed in 1998 had central air conditioners (Census Bureau, 1999). Air conditioning has also grown rapidly in mercial buildings. From 1970 to 1995, the percentage of mercial buildings with air conditioning increased from 54 to 73% (Jackson and Johnson, 1978, and DOE, 1998). Air conditioning in buildings is usually acplished with the use of mechanical or heatactivated equipment. In most applications, the air conditioner must provide both cooling and dehumidification to maintain fort in the building. Air conditioning systems are also used in other applications, such as automobiles, trucks, aircraft, ships, and industrial facilities. However, the description of equipment in this chapter is limited to those monly used in mercial and residential buildings. Commercial buildings range from large highrise office buildings to the corner convenience store. Because