冷干機(jī)在正常情況下，蒸發(fā)器表面有一層膜狀冷凝水存在。在計(jì)算蒸發(fā)器冷負(fù)荷時(shí)已經(jīng)考慮到這一情況。如果蒸發(fā)溫度降得很低，使換熱銅管表面溫度在零度以下，水蒸氣就會(huì)在銅管表面凝結(jié)成霜，由此產(chǎn)生的問(wèn)題是
冷干機(jī)在正常情況下，蒸發(fā)器表面有一層膜狀冷凝水存在。在計(jì)算蒸發(fā)器冷負(fù)荷時(shí)已經(jīng)考慮到這一情況。如果蒸發(fā)溫度降得很低，使換熱銅管表面溫度在零度以下，水蒸氣就會(huì)在銅管表面凝結(jié)成霜，由此產(chǎn)生的問(wèn)題是：
Under normal circumstances, there is a layer of film condensation water on the surface of the evaporator. This has been taken into account when calculating the cooling load of the evaporator. If the evaporation temperature is very low, so that the surface temperature of the copper pipe is below zero, the water vapor will condense on the surface of the copper tube into frost, the problem is:
①水蒸氣“升華為霜”比“凝結(jié)為露”要多吸收約15%的冷量；
Water vapor "sublimation" as frost "condensation" to absorb more than 15% of the amount of cold;
②霜的熱導(dǎo)率只有水的1/4，使管外空氣不能充分冷卻，而同時(shí)管內(nèi)蒸發(fā)溫度卻有進(jìn)一步降低的趨勢(shì)，如此循環(huán)的結(jié)果，必將給制冷系統(tǒng)帶來(lái)許多不良后果（譬如產(chǎn)生“液壓縮”）；
The thermal conductivity rate of only 1/4 of water frost, the air outside the tube can not be fully cooled, while tube evaporation temperature has further decreased, so the results will bring many adverse consequences to the refrigeration system (such as "liquid compression");
③從空氣流通徑講，霜的存在會(huì)使空氣阻力增加，使供氣壓力降低，嚴(yán)重時(shí)甚至?xí)箽饴范氯?/div>
Speaking from the air circulation, the presence of frost will increase the air resistance, so that the supply pressure is reduced, and even serious gas road blockage;
④從系統(tǒng)能耗來(lái)講，蒸發(fā)溫度過(guò)低導(dǎo)致壓縮機(jī)制冷系數(shù)大幅下降，能耗增加。所以含濕量很大的壓縮空氣進(jìn)入冷干機(jī)工作時(shí)，冷媒在管內(nèi)的蒸發(fā)溫度至少應(yīng)保證蒸發(fā)器銅管表面溫度在零度以上。試圖通過(guò)定時(shí)化霜的辦法來(lái)降低蒸發(fā)溫度，冷干機(jī)是不能接受的。
From the energy consumption of the system, the evaporation temperature is too low, which leads to the decrease of the compressor refrigeration coefficient and the increase of energy consumption. Therefore, a large amount of compressed air into the cold dry machine, the refrigerant in the tube evaporation temperature should be at least to ensure that the surface temperature of the evaporator tube above zero. It is not acceptable to try to reduce the evaporation temperature by the method of timing defrosting.
