scholarly journals A Time-Dependent Model for Predicting Thermal Environment of Mono-Slope Solar Greenhouses in Cold Regions

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5956
Author(s):  
Shuyao Dong ◽  
Md Shamim Ahamed ◽  
Chengwei Ma ◽  
Huiqing Guo
Keyword(s):  
Thermal Environment ◽  
Ground Surface ◽  
Average Error ◽  
Vegetable Production ◽  
Indoor Temperature ◽  
Cold Regions ◽  
Canadian Prairies ◽  
Average Prediction Error ◽  
The North ◽  
North Wall

Most greenhouses in the Canadian Prairies shut down during the coldest months (November to February) because of the hefty heating cost. Chinese mono-slope solar greenhouses do not primarily rely on supplemental heating; instead, they mostly rely on solar energy to maintain the required indoor temperature in winter. This study focuses on improving an existing thermal model, entitled RGWSRHJ, for Chinese-style solar greenhouses (CSGs) to increase the robustness of the model for simulating the thermal environment of the CSGs located outside of China. The modified model, entitled SOGREEN, was validated using the field data collected from a CSG in Manitoba, Canada. The results indicate that the average prediction error for indoor and relative humidity is 1.9 °C and 7.0%, and the rRMSE value is 3.3% and 11.5%, respectively. The average error for predicting the north wall and ground surface temperature is 4.2 °C and 2.3 °C, respectively. The study also conducted a case study to analyze the thermal performance of a conceptual CSG in Saskatoon, Canada. The energy analysis indicates the heating requirement of the greenhouse highly depends on the availability of solar radiation. Besides winter, the heating requirement is relatively low in March to maintain 18 °C indoor temperature when the average outdoor temperature was below –4 °C, and negligible during May–August. The results indicate that vegetable production in CSGs could save about 55% on annual heating than traditional greenhouses. Hence, CSGs could be an energy-efficient solution for ensuring food security for northern communities in Canada and other cold regions.

scholarly journals Effect of the ridge position ratio on the thermal environment of the Chinese solar greenhouse

2021 ◽  
Vol 8 (5) ◽  
Author(s):  
Xiaoyang Wu ◽  
Xingan Liu ◽  
Xiang Yue ◽  
Hui Xu ◽  
Tianlai Li ◽  
...  
Keyword(s):  
Structural Design ◽  
Cfd Simulation ◽  
Thermal Environment ◽  
The South ◽  
The North ◽  
Dependency Relationship ◽  
Solar Greenhouse ◽  
Computational Fluid Dynamics Cfd ◽  
North Wall ◽  
Maximum Air Temperature

This paper clarified the mechanism of the south and north roofs' effect on the thermal environment of the Chinese solar greenhouse (CSG), using a new parameter: ridge position ratio (RPR), which can describe the dynamic dependency relationship between the south and north roofs. A mathematical model was established using a method of combining computational fluid dynamics (CFD) simulation with experiments, then the model was used to further analyse the effect of RPR on the thermal environment of the CSG. The experimental greenhouse was simulated as an empty building to obtain results independently from these factors including crop and ventilation conditions. The results showed that the occurrence time of the maximum air temperature will be delayed when RPR increases to 0.3 during the daytime. As RPR increases, the heat storage layer of the soil gradually becomes thinner, but the north wall remains unchanged. RPR has a relatively small effect on the minimum temperature of each greenhouse part during the night. Mathematical models of the relationships between RPR, the solar energy that entered the greenhouse and the released heat energy of the enclosure structures were established, respectively. This paper can provide theoretical guidance for the structural design of the CSG.

scholarly journals Numerical investigation of the north wall passive thermal performance for Chinese solar greenhouse

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3465-3476
Author(s):  
Yiming Li ◽  
Xingan Liu ◽  
Fengsheng Qi ◽  
Li Wang ◽  
Tianlai Li
Keyword(s):  
Solar Energy ◽  
Wall Thickness ◽  
Thermal Performance ◽  
Thermal Environment ◽  
Energy Utilization ◽  
Wall Material ◽  
The North ◽  
Solar Energy Utilization ◽  
Solar Greenhouse ◽  
North Wall

The fully passive solar energy utilization system of Chinese solar greenhouse is efficient for ensuring year-round cultivation of vegetables, owing to the high amount of heat charge and discharge characteristic of the north wall enclosure. In the present research, the thermal performance is investigated using CFD. A 3-D mathematical model has been established to evaluate the wall thickness, layered configuration and material property. The predicted thermal environments are in good agreement with the experimental measurements, indicating the reliability of the established numerical model. The results showed that the increase of north wall thickness could cause the waste of resources due to the thermal masses mainly concentrate in the superficial layer. Constructing layered configuration is rec-ommended for the north wall which uses Styrofoam in the outer layer to reduce heat loss. Nevertheless, the property of north wall material has little effect on the thermal environment. The research results, thus obtained, will give good guidance for completing the Chinese solar greenhouse engineering database and optimizing the solar energy utilization.

Effect of north wall internal surface structure on heat storage-release performance and thermal environment of Chinese solar greenhouse

2021 ◽  
pp. 174425912110134
Author(s):  
Yiming Li ◽  
Xiang Yue ◽  
Lei Zhao ◽  
Hui Xu ◽  
Xingan Liu ◽  
...  
Keyword(s):  
Heat Storage ◽  
Thermal Environment ◽  
Internal Surface ◽  
Surface Structures ◽  
Indoor Thermal Environment ◽  
The North ◽  
Yield And Quality ◽  
Solar Greenhouse ◽  
North Wall ◽  
Striped Wall

Chinese solar greenhouse (CSG) is an energy-saving agricultural building which is used to grow vegetables in winter. The north wall of CSG plays an crucial role in concerning the production yield and quality during the winter months. To improve the thermal performance of north wall, different internal surface structures (ISS) with same materials were compared. Based on the field experiment and the proposed valuation, the dynamic heat storage-release characteristics of the north walls have been analyzed and discussed. The results showed that compared with the flat wall and the striped wall, the alveolate wall has better properties of heat storage and thermal insulation. Moreover, relative humidity in this type of greenhouse is more suitable for growing crops. The alveolate wall can improve indoor thermal environment and reduce the sensitivity to external environment. The obtained results can provide a basis for the scientific construction of the CSG north wall. It has significant potential for the area in high latitude, high altitude and long winter.

The Villa Item and a Bride's Ordeal

1929 ◽  
Vol 19 (1) ◽  
pp. 67-87 ◽  
Author(s):  
Jocelyn Toynbee
Keyword(s):  
The South ◽  
Important Paper ◽  
The North ◽  
Dwelling House ◽  
South Wall ◽  
The Subject ◽  
The One ◽  
The Individual ◽  
North Wall ◽  
The Right

The paintings in the triclinium of the Villa Item, a dwelling-house excavated in 1909 outside the Porta Ercolanese at Pompeii, have not only often been published and discussed by foreign scholars, but they have also formed the subject of an important paper in this Journal. The artistic qualities of the paintings have been ably set forth: it has been established beyond all doubt that the subject they depict is some form of Dionysiac initiation: and, of the detailed interpretations of the first seven of the individual scenes, those originally put forward by de Petra and accepted, modified or developed by Mrs. Tillyard appear, so far as they go, to be unquestionably on the right lines. A fresh study of the Villa Item frescoes would seem, however, to be justified by the fact that the majority of previous writers have confined their attention almost entirely to the first seven scenes—the three to the east of the entrance on the north wall (fig. 3), the three on the east wall and the one to the east of the window on the south wall, to which the last figure on the east wall, the winged figure with the whip, undoubtedly belongs.

scholarly journals Visual Observation of the Outcrop at the North Wall of the Tokyo Submarine Canyon in Sagami Bay, Central Japan using the ROV HYPER-DOLPHIN

2015 ◽  
Vol 121 (5) ◽  
pp. 161-166
Author(s):  
Shin'ichi Mori ◽  
Naoki Takahashi ◽  
Kenichiro Shibata ◽  
Yuichiro Tanaka ◽  
Daiji Hirata ◽  
...  
Keyword(s):  
Submarine Canyon ◽  
Visual Observation ◽  
Sagami Bay ◽  
Central Japan ◽  
The North ◽  
North Wall

scholarly journals Profitability of Organic Vegetable Production via Sod Based Rotation and Conventional Versus Strip Tillage in the Southern Coastal Plain

2016 ◽  
Vol 5 (4) ◽  
pp. 46 ◽  
Author(s):  
Mona Ahmadiani ◽  
Chun Li ◽  
Yaqin Liu ◽  
Esendugue Greg Fonsah ◽  
Christine Bliss ◽  
...  
Keyword(s):  
Crop Rotation ◽  
Coastal Plain ◽  
Conventional Tillage ◽  
Organic Production ◽  
Vegetable Production ◽  
Vegetable Crops ◽  
The North ◽  
Organic Vegetable Production ◽  
Strip Tillage ◽  
Rotation Sequence

<p class="sar-body"><span lang="EN-US">There are little economic data concerning the profitability of organic vegetable crops in the Southern Coastal Plain, especially in reference to sod-based rotation and tillage alternatives.  A three-year experiment was conducted at the North Florida Research and Education Center-Quincy involving a crop rotation sequence of oats and rye (winter), bush beans (spring), soybean (summer) and broccoli (fall). Bush beans and broccoli were the cash crops. This paper presents analyses of the riskiness of organic production utilizing years in bahiagrass prior to initiating the crop rotation sequence and conventional tillage (CT) versus strip tillage (ST). Methods of “Risk-rated enterprise budget” and “Analyses of Variance-Covariance Matrix (ANOVA)” were utilized for determining relative profitability, and coefficient of variation was applied for measuring riskiness of each treatment. Three years of bahiagrass prior to initiating the crop rotation sequence, in combination with conventional tillage, had the highest profitability and ranked as the least risky scenario.  The second most profitable treatment was conventional tillage with four years of bahiagrass. Focusing on strip tillage, four years of bahiagrass with strip-tillage ranked third in term of profitability.</span></p>

Factors affecting interannual variation in growth of western Canadian aspen forests during 1951-2000

2005 ◽  
Vol 35 (3) ◽  
pp. 610-622 ◽  
Author(s):  
EH (Ted) Hogg ◽  
James P Brandt ◽  
B Kochtubajda
Keyword(s):  
Populus Tremuloides ◽  
Interannual Variation ◽  
Regional Scale ◽  
Forest Health ◽  
Basal Area ◽  
Deciduous Tree ◽  
Severe Drought ◽  
Moisture Index ◽  
Canadian Prairies ◽  
The North

Trembling aspen (Populus tremuloides Michx.) is the most important deciduous tree in the North American boreal forest and is also the dominant tree in the aspen parkland zone along the northern edge of the Canadian prairies. Since the 1990s, observations of dieback and reduced growth of aspen forests have led to concerns about the potential impacts of climate change. To address these concerns, a regional-scale study (CIPHA) was established in 2000 that includes annual monitoring of forest health and productivity of 72 aspen stands across the western Canadian interior. Tree-ring analysis was conducted to determine the magnitude and cause of temporal variation in stand growth of aspen at the scale (1800 km × 500 km area) encompassed by this study. The results showed that during 1951–2000 the region's aspen forests underwent several cycles of reduced growth, notably between 1976 and 1981, when mean stand basal area increment decreased by about 50%. Most of the growth variation was explained by interannual variation in a climate moisture index in combination with insect defoliation. The results of the analysis indicate that a major collapse in aspen productivity likely occurred during the severe drought that affected much of the region during 2001–2003.

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