传热过程分析（热工分析）是任何热工设备设计和制作的理论依据。冷干机热工计算的目的是根据压缩空气状态（主要是进气压力和温度），确定其降温过程制冷系统所需要供给的制冷量Q、预冷器和蒸发器的负荷分配、计算冷干机排水量，同时也可借此预测排气干球温度t4。
传热过程分析（热工分析）是任何热工设备设计和制作的理论依据。冷干机热工计算的目的是根据压缩空气状态（主要是进气压力和温度），确定其降温过程制冷系统所需要供给的制冷量Q、预冷器和蒸发器的负荷分配、计算冷干机排水量，同时也可借此预测排气干球温度t4。
The analysis of heat transfer process (thermal analysis) is the theoretical basis for the design and manufacture of any thermal equipment. Cold and dry machine thermal calculation according to the compressed air condition (mainly inlet pressure and temperature), the cooling process of the refrigeration system to supply cooling capacity Q, pre cooler and evaporator load distribution calculation, cold and dry machine displacement, and also can be used to forecast the exhaust dry bulb temperature t4.
就其实质而论，冷干机是由两个换热器构成的复合式换热器，共有三种不同状态的流体参与了换热：
As a matter of fact, the cold dryer is a compound heat exchanger consisting of two heat exchangers. There are three different states of fluid involved in the heat exchange.
①预冷器里，热流体是温度较高的饱和压缩空气，冷流体是冷却后相对干燥的压缩空气，两者水当量（定压比热与质量的乘积）极为接近；
(1) in the precooler, the hot fluid is a high temperature saturated compressed air, and the cold fluid is the relatively dry compressed air after cooling. The water equivalent of the two parts is very close to the product of constant pressure and specific heat.
②蒸发器里热流体是温度已预先降低了的饱和压缩空气，冷流体是冷媒蒸汽。
The thermal fluid in the evaporator is the saturated compressed air which has been reduced in advance by the temperature, and the cold fluid is the refrigerant steam.
蒸发器由独立的制冷系统提供冷源，而预冷器的冷源则来自通过蒸发器冷却了的压缩空气，因而不具备独立性。所以说，在整个热交换过程中预冷器的作用是回收制冷系统产生的部分冷量，客观上减少了整机的能量消耗。
The evaporator provides a cold source by an independent refrigeration system, while the cold source of the precooler comes from the compressed air cooled by the evaporator, and thus does not have independence. Therefore, in the whole process of heat exchange, the function of the precooler is to recover part of the cooling capacity produced by the refrigeration system and reduce the energy consumption of the whole machine.
