【正文】 is generated internally by nonhomogeneous densities caused by temperature variation, the heat transfer is termed natural convection or free convection.When fluid currents are produced by external sources (for example, a blower or pump), the solidtofluid heat transfer is termed forced convection. If the fluid flow is generated internally by nonhomogeneous densities caused by temperature variation, the heat transfer is termed natural convection or free convection.當流體的電流是由外部來源（例如，一個鼓風(fēng)機或泵），固 液傳熱被稱為強迫對流。公式（1）在x方向的熱流率q是成正比的溫度梯度DT/ DX和橫截面積一個正常的熱流。Thermodynamic wetbulb temperature t* is the temperature at which water (liquid or solid), by evaporating into moist air at a given drybulb temperature t and humidity ratio W, can bring air to saturation adiabatically at the same temperature t* while the total pressure p is maintained constant. This parameter is considered separately in the section on Thermodynamic WetBulb and DewPoint Temperature.熱力學(xué)濕球溫度T *是在水（液體或固體），潮濕的空氣中蒸發(fā)，在一個給定的干球溫度t和濕度比W的溫度，可以使空氣飽和絕熱在同一溫度T*而總壓力p保持不變。Air contaminants are generally either particles or gases. The distinction between particles and gases is important when determining removal strategies and equipment. Although the motion of particles is described using the same equations used to describe gas movement, even the smallest of particles (approximately 1 nm) are much larger than individual gas molecules, have a much greater mass, and a much lower diffusion rate. 空氣污染物一般是顆?；驓怏w。然而，它需要在一個中央位置的空間和一個潛在的大分配制度。使用較高的水溫度上升和較低的送風(fēng)溫度，降低了所需的泵和風(fēng)扇能源在某些情況下，抵消，由于冰所需溫度較低的能量損失。無論是自然通風(fēng)或機械通風(fēng)冷卻塔或噴池塘用于拒絕到大氣中的熱量。蒸發(fā)式冷凝器，通水噴灑線圈，室外空氣。存儲容量為夏季負荷平衡安裝，也可能是在冬季使用，高熱不退更可行的選擇。他們中的濃度每立方厘米在受污染的城市環(huán)境的范圍在清潔的環(huán)境中從100 particles/cm3百萬的氣氛。在一般情況下，舒適性發(fā)生時體溫都在窄幅內(nèi)舉行，皮膚水分低，調(diào)節(jié)生理努力最小化。減號表示熱流溫度降低的方向積極。熱能量轉(zhuǎn)移發(fā)生在溫度降低的方向。Heat is energy in transit due to a temperature difference. The thermal energy is transferred from one region to another by three modes of heat transfer: conduction, convection, and radiation. Heat transfer is among a group of energy transport phenomena that includes mass transfer, momentum transfer or fluid friction and electrical conduction. 熱是由于溫差在傳輸過程中的能量。雖然液體和氣體的分子運動特性有著很大的區(qū)別，但是他們的主要的力學(xué)區(qū)別在于可壓縮性的程度和液體自由表面（界面）的形成。可逆循環(huán)有兩個重要的屬性：（1）無制冷循環(huán)的性能系數(shù)之間相同的溫度限制經(jīng)營的可逆循環(huán)高于，（2）之間相同的溫度極限運行時，所有可逆循環(huán)，同樣的性能系數(shù)Flowing fluids in heating, ventilating, airconditioning, and refrigeration systems can transfer heat, mass, and momentum. This chapter introduces the basics of fluid mechanics related to HVAC processes, reviews pertinent flow processes, and presents a general discussion of singlephase fluid flow analysis.流動的液體在加熱，通風(fēng)，空調(diào)和制冷系統(tǒng)，可以傳遞熱量，質(zhì)量和動量。當蒸汽溫度大于飽和溫度，它是一個熱蒸氣。 功是指通過存在壓差（任一種力）的系統(tǒng)邊界傳遞能量的作用過程，總是指向低壓，如果系統(tǒng)中產(chǎn)生的總效果能被簡化為一個重物的提升，那么只有功通過了邊界，當能量從系統(tǒng)中一出時，功是正的。這些邊界可以是動產(chǎn)或固定的，真實的或想象。熵措施分子系統(tǒng)紊亂。最常見的熱力學(xué)性質(zhì)的溫度T，壓力P，和特定的體積V或密度ρ。焓H，一個屬性相結(jié)合的結(jié)果，被定義為：H = U + PV其中u是每單位質(zhì)量的內(nèi)部能量Each property in a given state has only one definite value, and any property always has the same value for a given state, regardless of how the substance arrived at that state. A process is a change in state that can be defined as any change in the properties of a system. A process is described by specifying the initial and final equilibrium states, the path (if identifiable), and the interactions that take place across system boundaries during the process. 中的每一個給定的狀態(tài)的屬性只有一個定值，和任何財產(chǎn)總是有相同的值給定的狀態(tài)，不管如何抵達該國的物質(zhì)。A cycle is a process or a series of processes wherein the initial and final states of the system are identical. Therefore, at the conclusion of a cycle, all the properties have the same value they had at the beginning. A pure substance has a homogeneous and invariable chemical position. It can exist in more than one phase, but the chemical position is the same in all phases一個周期進程的一個過程或一個系列，其中系統(tǒng)的初始和最終狀態(tài)是相同的的。The second law of thermodynamics differentiates a