空气-空气热交换器去湿冷却工况的计算

在间接蒸发冷却技术中,空气-空气热交换器是一个重要设备。二次空气通过直接蒸发冷却后降低了温度,然后通过热交换器去冷却一次空气。当二次空气的入口温度低于一次空气的露点温度时,一次空气的冷却有可能是一去湿过程。通常制造厂仅提供干冷却时的换热效率,这使得难以计算去湿冷却工况。为了克服这一困难,本文提出一个新的方法,利用此法,即使只有干冷却效率也能计算在去湿冷却条件下一次空气和二次空气的参数。此法限用于逆流情况下的板式热交换器。文中还提供了计算实例以作进一步的阐明。

Calculation of the Dehumidifying Process of Air-to-Air Heat Exchangers

The air-to-air heat exchanger is an important component in an indirect eva-porative cooling cycle. The secondary air temperature is decreased by directevaporative cooling. Then this air goes into the heat exchanger to cool the primaryair. When the entering temperature of the secondary air is lower than the dewpoint temperature of the primary air, there may be a dehumidifying cooling pro-cess in the primary air passages. Usually manufacturers give only the data ofsensible cooling effectiveness. It makes the calculation of the dehumidifyingcooling process quite difficult. For solving this difficulty this paper presents anew method of calculation, by which the parameters of the primary and thesecondary air under dehumidifying cooling process can be calculated even if theonly given value is sensible cooling effectiveness. Herein only the plate type ofair-to-air heat exchangers with a counter flow is discussed, In addition an exam-ple is presented for further explanation.