基于自然冷资源利用的湿冷系统设计及性能试验

Design and experimental of humidicooling system based on the natural cool resource utilization

利用自然冷资源保鲜具有安全、节能、环保等优点。综合传统冰水湿冷系统特点,设计喷雾式冷风机湿冷系统,分析和测试喷淋水量、迎面风速、湿球温度对湿冷系统制冷性能影响。结果表明,当喷淋水量从0.08 m^3·h^(-1)增至0.20 m^3·h^(-1),制冷量平均变化率增加60.7%,确定最小喷淋水量为0.14 m^3·h^(-1);迎面风速取1.5~4.0 m·s-1,总换热系数增加46%,空气对流传质系数增加43%,能效比(EER)增加5%;当空气湿球温度从12℃增至24℃时,制冷量和能效比分别减少5.0%和5.3%,表明该系统适合气候干燥地区使用;不必对喷雾水降温,使用过滤后的自来水,干工况下总换热系数比全工况总换热系数下降75%;该湿冷系统预冷时间短,可实现低温(水为介质3.8℃,盐水为介质1.9℃)、高湿(92%RH^100%RH)且相对稳定的保鲜环境。

Natural cool resource had many advantages, such as safety, energy conservation and environment protection. A new humidicooling system of water spraying air-cooler was designed based on the characteristics of the traditional ice water humidicooling system. The influence of web-bulb temperature, the spray water and the head-on air velocity on the performance of the system were analyzed in the experiments. Experimental results showed that when the spray water amount increased from 0.08 to 0.20 m^3·h^（-1）, the average cooling capacity rate increased by 60.7%, the minimum spray water amount was 0.14 m^3·h^（-1）; The experiments were conducted under the head-on air velocity increased from 1.5 to 4.0 m·s-1, and the results showed that the increased of the average overall heat transfer coefficient was 46%, the increases of the average air mass transfer coefficient was 43%, and the increases of the energy efficiency ratio（EER） was 5%. When the web-bulb temperature of air increased from 12 to 24 ℃, the cooling capacity and EER decreased by 5.0% and 5.3%, indicating that the humidicooling system especially adapted to the dry regions. Considering the economic aspect, the water of filtered tap could be used directly. Under the dry condition the overall heat transfer coefficient decreased by 75% than in the wet condition. The system precooling time was short, and could maintained low temperature（water was 3.8 ℃, salt water was 1.9℃）, high humidity（92%RH-100%RH）and relatively stable condition in the process of cold storage for keeping vegetables.