Study on the Natural Ventilation Characteristics of a Solar Greenhouse in a High-Altitude Area
The ventilation rate of a greenhouse is one of the major factors to consider when assessing its ventilation performance. Compared with plain areas, high-altitude areas have lower air pressure, thinner air, and stronger solar radiation, which in turn affect the magnitude of the local greenhouse venti...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Agronomy |
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| Online Access: | https://www.mdpi.com/2073-4395/12/10/2387 |
| _version_ | 1797476131787505664 |
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| author | Bohua Liang Shumei Zhao Yanfeng Li Pingzhi Wang Zhiwei Liu Jingfu Zhang Tao Ding |
| author_facet | Bohua Liang Shumei Zhao Yanfeng Li Pingzhi Wang Zhiwei Liu Jingfu Zhang Tao Ding |
| author_sort | Bohua Liang |
| collection | DOAJ |
| description | The ventilation rate of a greenhouse is one of the major factors to consider when assessing its ventilation performance. Compared with plain areas, high-altitude areas have lower air pressure, thinner air, and stronger solar radiation, which in turn affect the magnitude of the local greenhouse ventilation rate. This paper is based on the use of online monitoring and computational fluid dynamics (CFD) techniques for modeling and model validation. The average relative error (ARE), mean absolute error (MAE), root-mean-square error (RMSE), and determination coefficient (R<sup>2</sup>) of the temperature were 4.88%, 1.396 °C, 1.428 °C, and 0.9982, respectively. The ARE, MAE, RMSE, and R<sup>2</sup> of the velocity were 9.525%, 0.035 m/s, 0.049 m/s, and 0.9869, respectively. Then, the distributions of the wind pressure, Reynolds number (Re), thermal pressure, air density, air speed, and temperature in greenhouses in high-altitude and plain areas were researched to obtain the relevant factors affecting the ventilation rates of greenhouses in high-altitude areas. In addition, correlation analyses were conducted for five variables affecting the ventilation rate: the inlet velocity, the temperature difference between the inside and outside of the greenhouse, the air density difference between the inside and outside of the greenhouse, total indoor radiation, and the internal heat source of the crop, and the coefficients of their correlations with the greenhouse ventilation rate were 1.0, −0.83, −0.72, −0.72, and 0.68, respectively. A natural ventilation rate model for plateau areas was developed, with the ARE, RMSE, and R<sup>2</sup> between the sample values and fitted values determined to be 4.55%, 0.543 m<sup>3</sup>/s, and 0.9997, respectively. The model was validated by predicting the greenhouse ventilation rate in winter (3 January 2022), and the ARE, RMSE, and R<sup>2</sup> of the sample values and predicted values were 9.726%, 8.435 m<sup>3</sup>/s, and 0.9901, respectively. This study provides a theoretical basis for further research on greenhouse ventilation characteristics in high-altitude areas. |
| first_indexed | 2024-03-09T20:54:35Z |
| format | Article |
| id | doaj.art-8124aed4d01e447e9c8edccd0d00ba57 |
| institution | Directory Open Access Journal |
| issn | 2073-4395 |
| language | English |
| last_indexed | 2024-03-09T20:54:35Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Agronomy |
| spelling | doaj.art-8124aed4d01e447e9c8edccd0d00ba572023-11-23T22:26:16ZengMDPI AGAgronomy2073-43952022-10-011210238710.3390/agronomy12102387Study on the Natural Ventilation Characteristics of a Solar Greenhouse in a High-Altitude AreaBohua Liang0Shumei Zhao1Yanfeng Li2Pingzhi Wang3Zhiwei Liu4Jingfu Zhang5Tao Ding6College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100080, ChinaCollege of Water Resources and Civil Engineering, China Agricultural University, Beijing 100080, ChinaTibet Academy of Agricultural and Animal Husbandry Sciences, Lhasa 851418, ChinaCollege of Water Resources and Civil Engineering, China Agricultural University, Beijing 100080, ChinaInfrastructure Construction Department, China Agricultural University, Beijing 100080, ChinaCollege of Water Resources and Civil Engineering, China Agricultural University, Beijing 100080, ChinaCollege of Water Resources and Civil Engineering, China Agricultural University, Beijing 100080, ChinaThe ventilation rate of a greenhouse is one of the major factors to consider when assessing its ventilation performance. Compared with plain areas, high-altitude areas have lower air pressure, thinner air, and stronger solar radiation, which in turn affect the magnitude of the local greenhouse ventilation rate. This paper is based on the use of online monitoring and computational fluid dynamics (CFD) techniques for modeling and model validation. The average relative error (ARE), mean absolute error (MAE), root-mean-square error (RMSE), and determination coefficient (R<sup>2</sup>) of the temperature were 4.88%, 1.396 °C, 1.428 °C, and 0.9982, respectively. The ARE, MAE, RMSE, and R<sup>2</sup> of the velocity were 9.525%, 0.035 m/s, 0.049 m/s, and 0.9869, respectively. Then, the distributions of the wind pressure, Reynolds number (Re), thermal pressure, air density, air speed, and temperature in greenhouses in high-altitude and plain areas were researched to obtain the relevant factors affecting the ventilation rates of greenhouses in high-altitude areas. In addition, correlation analyses were conducted for five variables affecting the ventilation rate: the inlet velocity, the temperature difference between the inside and outside of the greenhouse, the air density difference between the inside and outside of the greenhouse, total indoor radiation, and the internal heat source of the crop, and the coefficients of their correlations with the greenhouse ventilation rate were 1.0, −0.83, −0.72, −0.72, and 0.68, respectively. A natural ventilation rate model for plateau areas was developed, with the ARE, RMSE, and R<sup>2</sup> between the sample values and fitted values determined to be 4.55%, 0.543 m<sup>3</sup>/s, and 0.9997, respectively. The model was validated by predicting the greenhouse ventilation rate in winter (3 January 2022), and the ARE, RMSE, and R<sup>2</sup> of the sample values and predicted values were 9.726%, 8.435 m<sup>3</sup>/s, and 0.9901, respectively. This study provides a theoretical basis for further research on greenhouse ventilation characteristics in high-altitude areas.https://www.mdpi.com/2073-4395/12/10/2387high altitudeCFD simulationwind pressurethermal pressureventilation rate |
| spellingShingle | Bohua Liang Shumei Zhao Yanfeng Li Pingzhi Wang Zhiwei Liu Jingfu Zhang Tao Ding Study on the Natural Ventilation Characteristics of a Solar Greenhouse in a High-Altitude Area Agronomy high altitude CFD simulation wind pressure thermal pressure ventilation rate |
| title | Study on the Natural Ventilation Characteristics of a Solar Greenhouse in a High-Altitude Area |
| title_full | Study on the Natural Ventilation Characteristics of a Solar Greenhouse in a High-Altitude Area |
| title_fullStr | Study on the Natural Ventilation Characteristics of a Solar Greenhouse in a High-Altitude Area |
| title_full_unstemmed | Study on the Natural Ventilation Characteristics of a Solar Greenhouse in a High-Altitude Area |
| title_short | Study on the Natural Ventilation Characteristics of a Solar Greenhouse in a High-Altitude Area |
| title_sort | study on the natural ventilation characteristics of a solar greenhouse in a high altitude area |
| topic | high altitude CFD simulation wind pressure thermal pressure ventilation rate |
| url | https://www.mdpi.com/2073-4395/12/10/2387 |
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