Optimization of pipe form parameters of desiccant rotary wheels of dehumidification system for storage

Controlling the humidity in environment is very important for qualities of storage.In order to improve the working performance of desiccant rotary wheels of dehumidification system for the storage and the relative humidity uniformity of the storage environment, a set of pipeline type wheel dehumidifying device was integrated into the existing dehumidification system in this study.By increasing pipeline type passage of dry air, the pattern of indoor air flow was rearranged from middle-in and bottom-out to pipe-in and bottom-out.In this study, hybrid rice seeds were used as the test material.To determine the dehumidifying effect of the modified system, a three-factor three-level orthogonal experiment for the prototype was carried out and the results were analyzed.Experiment was carried out at temperature of 25 ℃, airflow velocity of 5 m/s, and cargo stacking in the intermediate bottom.For the 3 factors in the experiment, pipeline location was set as 1.25, 0.65 and 0.05 m, pipe diameter was set as 50, 40 and 32 mm, and number of holes on pipes was set as 5, 10 and 20.With the pipeline type wheel dehumidifying device, the relative humidity in the container could be decreased from 95% to 30%.When the pipeline was located at 0.05 m above the bottom of the container, the pipeline diameter was 50 mm, and the number of holes on pipes was 20.It was found this relative humidity distribution was the most uniform, and the coefficient of variance of relative humidity was 3.81%, which was about only 15% of the worst case.Because the position of the air supply pipe determined the revolving flow of the whole flow field.Meanwhile, it was found that the best dehumidifying effect occurred under the conditions that the pipeline location was 0.65 m, the pipe diameter was 40 mm, and the number of holes on pipes was 20.The capacity of the desiccant in combination of the pipeline location of 0.65 m, the pipe diameter of 40 mm, and the 20 holes on pipes was 71.74 g/(kg?h), which was about twice of that in the worst case.The corresponding efficiency of the desiccant was 0.0906 g/(kg?h?kJ), which was 3 times that of the worst case.Taking into account the overall effect of the desiccant, more attention should be paid to the performance of the desiccant capacity and efficiency.The results show that the number of holes on pipes makes the strongest unique contribution to the capacity and efficiency of the desiccant, followed by the pipe diameter and the pipeline location.Overall, the research can provide guideline information for the optimization design of dehumidification system for the storage.