Microclimate Air Motion and Uniformity of Indoor Plant Factory System: Effects of Crop Planting Density and Air Change Rate
In a plant factory, maintaining proper and uniform air/moisture movement above the crop canopy is crucial for aiding plant growth. This research has utilized a three-dimensional computation model to investigate airflow and heat transfer in a plant factory, where airflow, heat, and humidity distribut...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-04-01
|
| Series: | Applied Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-3417/15/8/4329 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | In a plant factory, maintaining proper and uniform air/moisture movement above the crop canopy is crucial for aiding plant growth. This research has utilized a three-dimensional computation model to investigate airflow and heat transfer in a plant factory, where airflow, heat, and humidity distributions above plant crops were calculated concerning five categories of crop planting density (<i>P<sub>d</sub></i>) and air change rate (<i>ACH</i>) in the crop area. Spatial uniformities of airflow velocity, temperature, and relative humidity immediately above the crops are evaluated using the objective uniformity parameter (<i>OU</i>), relative standard deviation of temperature (<i>RSD<sub>T</sub></i>) and relative standard deviation of relative humidity (<i>RSD<sub>RH</sub></i>), respectively. Furthermore, a factor of effectiveness (<i>θ</i>) is defined, depending on the uniformity of velocity, temperature, and relative humidity distribution, to comprehensively evaluate the impact of various <i>ACH</i> with <i>P<sub>d</sub></i> on overall effectiveness. Full numerical results show that air velocity, temperature, and relative humidity above the crops are notably influenced by <i>P<sub>d</sub></i> and <i>ACH</i>. As <i>ACH</i> increases, the <i>OU</i> of the air above the indoor crop also expands. Moreover, higher <i>OU</i> values are observed for smaller crop <i>P<sub>d</sub></i>. However, excessively small crop area planting densities and excessively large <i>ACH</i> do not result in a higher <i>OU</i> for the air above the crop. As <i>ACH</i> increases, both <i>RSD<sub>T</sub></i> and <i>RSD<sub>RH</sub></i> decay for the whole range of crop <i>P<sub>d</sub>.</i> Moreover, smaller <i>P<sub>d</sub></i> values could achieve the uniformity of thermal fields, while having minimal effects on the relative humidity distributions. Generally, increasing <i>ACH</i> and decreasing <i>P<sub>d</sub></i> could enhance overall value of <i>θ</i>. However, excessively increasing <i>ACH</i> and decreasing <i>P<sub>d</sub></i> does not have a significant effect on <i>θ</i>, which is jointly influenced by <i>OU</i>, <i>RSD<sub>T</sub></i>, and <i>RSD<sub>RH</sub></i>. Therefore, a more suitable combination of <i>ACH</i> and <i>P<sub>d</sub></i> is urgently required to improve the design of agricultural system to enhance crop microclimate uniformity for optimal plant growth and productivity. |
|---|---|
| ISSN: | 2076-3417 |