双级直膨式新风机性能的实验研究

发布时间：2019-04-13 08:17

【摘要】：直膨式新风机采用表面式蒸发器处理新风,处理后空气的含湿量较低,可满足绝大多数情况下温湿度独立控制系统对新风含湿量处理的要求。但直膨式新风机的负荷卸载和低负荷时系统的稳定性等问题制约了其应用。在全年工况下,室外新风温度和含湿量变化较大,工况负荷相差很大。探索使直膨式新风机既满足高温、高湿工况下的除湿降温要求,又能在低负荷工况下稳定高效运行的方法对促进直膨式新风机广泛应用具有重要意义。本文先设计了一种双级直膨式新风机,两级独立制冷并利用二级系统冷凝器调节送风温度。然后通过实验研究了不同因素对该新风机性能的影响和该新风机在广州地区极湿工况和空调期工况的运行性能。首先,本文研究了进口空气干球温度、湿球温度和中间温度(一级蒸发器出风温度)对该双级直膨式新风机性能的影响。实验结果表明:因一级制冷系统容量为二级制冷系统容量的3.4倍,所以一级系统的性能对新风机整体性能影响非常大。新风机进口干、湿球温度和中间温度对一级制冷系统和新风机整体性能影响的规律基本一致。在干球温度实验工况下,新风机进口干球温度对制冷量、显热比、输入功率、Energy Efficiency Ratio(EER)、再热量和送风含湿量影响较小。除湿量、显热量和潜热量受干球温度影响较大。湿球温度为25℃时,干球温度每升高3℃,除湿量平均减小0.87g/s,平均减幅为14.6%;显热量平均增大3.08kW,平均增幅为16.8%;潜热量平均减小2.15kW,平均减幅为14.3%。在湿球温度实验工况下,新风机进口湿球温度对制冷量、显热量、显热比、EER、再热量和送风含湿量影响较小。除湿量、潜热量和输入功率受湿球温度影响较大。风量为3000m3/h时,湿球温度每升高1℃,除湿量平均增大1.19g/s,平均增幅为21.4%;潜热量平均增大2.99kW,平均增幅为21.2%;输入功率平均增大1.07kW,平均增幅为12.2%。在中间温度实验工况下,中间温度对新风机各性能参数的影响均比较大,其中最为突出的是输入功率、再热量和送风含湿量。风量为3000m3/h时,中间温度每升高2℃,输入功率平均减小3.18kW,平均减幅为28.2%;再热量平均减小3.65kW,平均减幅为31.3%;送风含湿量平均增加2.09g/kg干空气,平均增幅为37.5%。其次,本文研究了该双级直膨式新风机在广州地区极湿工况和空调期工况的运行性能。极湿实验工况下,新风机运行风量为2000m3/h,中间温度14℃,送风温度22℃。该双级直膨式新风机的EER在2.32~2.62之间,送风含湿量在7.92~8.55g/kg干空气之间。因测试平台加热和加湿能力的限制,空调期工况实验分为两部分,低焓值段风量为3000m3/h,高焓值段风量为1000m3/h。低焓值段时该新风机EER在3.45~4.16之间,送风含湿量在7.74~8.01g/kg干空气之间;高焓值段时该新风机EER在3.09~3.46之间,送风含湿量在8.92~9.14g/kg干空气之间。相同风量时,该新风机EER和送风含湿量均随进口空气焓值升高而增大。
[Abstract]:The surface evaporator is used to deal with the fresh air. The moisture content of the air after treatment is low, which can meet the requirements of the independent control system of temperature and humidity in most cases for the treatment of the moisture content of the fresh air. However, the problems of load unloading and system stability at low load limit its application. The outdoor fresh air temperature and moisture content change greatly in the whole year, and the load of outdoor fresh air varies greatly. It is of great significance to explore the method that can not only satisfy the requirements of dehumidification and cooling under high temperature and high humidity conditions, but also can operate stably and efficiently under low load conditions, in order to promote the wide application of direct expansion new fans. In this paper, a two-stage direct-expansion new fan is designed, two-stage independent refrigeration and two-stage system condenser are used to adjust the air supply temperature. Then the effects of different factors on the performance of the new fan and the performance of the new fan under extremely wet and air conditioning conditions in Guangzhou are studied experimentally. Firstly, the effects of inlet air dry bulb temperature, wet bulb temperature and intermediate temperature (outlet air temperature of the first-stage evaporator) on the performance of the two-stage direct-expansion new fan are studied in this paper. The experimental results show that because the capacity of the first stage refrigeration system is 3.4 times that of the second stage refrigeration system, the performance of the first stage system has a great influence on the overall performance of the new fan. The effects of dry inlet wet bulb temperature and intermediate temperature on the whole performance of the first stage refrigeration system and the new fan are basically consistent. Under the experimental condition of dry bulb temperature, the inlet dry bulb temperature of the new fan has little effect on the cooling capacity, sensible heat ratio, the input power, Energy Efficiency Ratio (EER), reheat and the moisture content of the air supply. The dehumidification, apparent heat and latent heat are greatly affected by dry bulb temperature. When the wet bulb temperature is 25 鈩，

本文编号：2457403