The aim of this study is to improve the thermal performance of air-to-air heat recovery units, containing heat pipes by using graphene/water nanofluid as a working fluid. The experimental set up of this work consists of two air ducts. To study the effect of the airflow rate and the temperature on the performance of the heat recovery unit, different values of airflow rates and temperatures are used. The values of Re numbers are calculated for each air duct. These Re numbers referred to the turbulent flow type in all cases. To compare the results of the graphene/water nanofluid and the pure water working fluid, thermal efficiency and thermal resistance values are calculated for both of them. The results showed that the graphene/water nanofluid was more efficient than pure water in all different conditions. Re number in the cold air duct was 6800, and the Re number in the hot air duct was 9000. The maximum thermal efficiency values were 34.1 % and 20.1 % for graphene/water nanofluid and pure water, respectively. The maximum improvement rate in thermal efficiency was 87.7 % when the average Re number in cold and hot air ducts was equal to 11,150 and 11,650, respectively. By comparing the results of graphene/water nanofluid with those of the pure water, it can be seen that using graphene/water nanofluid decreased the thermal resistance of the heat pipes. Therefore, the heat transfer increased. The maximum decreasing value of the thermal resistance was 52.3 % when cold and hot air duct Re numbers were 11,700 and 11,000, respectively.

这项研究的目的是通过使用石墨烯/水纳米流体作为工作流体来改善包含热管的空对空热回收装置的热性能。这项工作的实验装置包括两个风道。为了研究气流速率和温度对热回收单元性能的影响，使用了不同的气流速率和温度值。为每个风管计算Re数值。在所有情况下，这些Re数均表示湍流类型。为了比较石墨烯/水纳米流体和纯水工作流体的结果，计算了两者的热效率和热阻值。结果表明，在所有不同条件下，石墨烯/水纳米流体均比纯水更有效。在冷气管道中的再编号是6800，热风管中的Re值为9000。石墨烯/水纳米流体和纯水的最大热效率值分别为34.1％和20.1％。当冷空气管道和热空气管道中的平均Re数分别等于11,150和11,650时，热效率的最大提高率为87.7％。通过将石墨烯/水纳米流体的结果与纯水的结果进行比较，可以看出使用石墨烯/水纳米流体的结果降低了热管的热阻。因此，热传递增加。冷热风管Re数分别为11,700和11,000时，热阻的最大降低值为52.3％。分别。当冷空气管道和热空气管道中的平均Re数分别等于11,150和11,650时，热效率的最大提高率为87.7％。通过将石墨烯/水纳米流体的结果与纯水的结果进行比较，可以看出使用石墨烯/水纳米流体的结果降低了热管的热阻。因此，热传递增加。冷热风管Re数分别为11,700和11,000时，热阻的最大降低值为52.3％。分别。当冷空气管道和热空气管道中的平均Re数分别等于11,150和11,650时，热效率的最大提高率为87.7％。通过将石墨烯/水纳米流体的结果与纯水的结果进行比较，可以看出使用石墨烯/水纳米流体的结果降低了热管的热阻。因此，热传递增加。当冷热风管的Re数分别为11,700和11,000时，热阻的最大降低值为52.3％。可以看出，使用石墨烯/水纳米流体降低了热管的热阻。因此，热传递增加。冷热风管Re数分别为11,700和11,000时，热阻的最大降低值为52.3％。可以看出，使用石墨烯/水纳米流体降低了热管的热阻。因此，热传递增加。冷热风管Re数分别为11,700和11,000时，热阻的最大降低值为52.3％。