膜式叉流新风热回收装置结霜及换热效率的影响因素实验

Experiment on Heat Transfer Efficiency and Influence Factors of Frosting in Cross-Flow Air-to-Air Membrane Heat Exchanger

利用焓差实验室模拟室内外温、湿度工况,对膜式叉流新风热回收装置进行了实测和分析,得到了室内温度、室内湿度和室外温度对结霜及交换效率的影响规律。实验结果表明:在低温工况即易结霜工况下,膜式叉流新风热回收装置排风侧出口空气温湿度明显分布不均,排风口平均温度不能作为安全运行的依据,而应以传热传湿最不利点的温度作为判定依据;相较于新风预热,排风除湿是更有效的防结霜方式;结霜工况下,室内相对湿度对交换效率的影响大于室内温度和室外温度的影响,原因是芯体内部结霜显著增大了传热和传湿阻力;非结霜工况下,各交换效率不受室内相对湿度的影响。

The enthalpy difference laboratory is used to simulate indoor and outdoor temperature and humidity conditions.The cross-flow air-to-air membrane heat exchanger is measured and analyzed.The effects of indoor temperature,indoor humidity and outdoor temperature on frosting and exchange efficiency are obtained.The experimental results show that under the condition of low temperature working conditions,i.e.,easy frosting,the air temperature and humidity of the outlet side of the cross-flow air-to-air membrane heat exchanger is obviously unevenly distributed,and the average temperature of the exhaust outlet could not be used as the basis for safe operation.The temperature at the most unfavorable point of heat transfer and moisture transmission is used as the basis for determination;compared with fresh air preheating,exhaust air dehumidification is a more effective anti-frosting method;under frosting conditions,the influence of indoor relative humidity on exchange efficiency is greater than the influence of indoor temperature and outdoor temperature,because the internal frosting of the core significantly increase the heat transfer and moisture transfer resistance;under non-frosting conditions,the exchange efficiency is not affected by the indoor relative humidity.