Analytical study on solar energy absorbed on elliptic curved collector

Tanaka, Hiroshi; El‐Maghlany, Wael M.; Teamah, Mohamed A.

doi:10.1016/j.solener.2015.03.025

Cited by 11 publications

(8 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the curved surface, from June to September, with an ojival shape, absorbs less solar radiation as the height, f, increases in relation to the width, l. In contrast, from December to March, the opposite occurs when compared to an inclined flat surface [15]. Therefore, ojival-shaped roofs become less efficient in capturing solar energy as β increases and the roof surface becomes larger.…”

Section: Influence Of the Roof Type On Heat Losses And Gainsmentioning

confidence: 99%

“…To compare different greenhouse roof forms when f and l vary, it is recommended to calculate both solar radiation capture and heat losses using the ratio Ac/Ag, defined as the ratio of the roof surface Ac to the cultivated ground surface Ag [15,49]. The results for the four roof types (Figure 11b) show that as the value of β increases, the Ac/Ag ratio also increases.…”

Section: Influence Of the Roof Type On Heat Losses And Gainsmentioning

confidence: 99%

“…The Gothic or ogival-shaped cover is the most efficient in capturing solar energy for cold climates and high latitudes [14]. In warm climates and middle latitudes, the arched shape receives the least annual radiation and would be more appropriate when energy needs are higher due to cooling [12,15,16].…”

Section: Introductionmentioning

confidence: 99%

“…Other studies show that the overall light transmittance of the greenhouse increases with the angle of the cover up to values of 28° to 32°, beyond which it barely changes, and the accumulation of energy due to solar radiation on the greenhouse floor decreases [22]. The cover angle is implicitly considered through the ratio, Z, defined as the height of the greenhouse/span width, finding that solar radiation interception increases with increasing Z [15], compensating for part of the decrease that occurs with increasing latitude.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Geometric analysis of greenhouse roofs for energy efficiency optimization and condensation drip reduction

Peña-Fernández,

Colón Reynoso,

Mazuela

2024

Preprint

View full text Add to dashboard Cite

show abstract

Section: Influence Of the Roof Type On Heat Losses And Gainsmentioning

confidence: 99%

Section: Influence Of the Roof Type On Heat Losses And Gainsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Geometric analysis of greenhouse roofs for energy efficiency optimization and condensation drip reduction

Peña-Fernández,

Colón Reynoso,

Mazuela

2024

Preprint

View full text Add to dashboard Cite

show abstract

“…Gothic and ogival-shaped covers are the most efficient at capturing solar energy for cold climates and high latitudes [14]. In warm climates and middle latitudes, arched covers receive the least annual radiation and would be more appropriate when energy needs are higher due to cooling [12,15,16].…”

Section: Introductionmentioning

confidence: 99%

Geometric Analysis of Greenhouse Roofs for Energy Efficiency Optimization and Condensation Drip Reduction

Peña-Fernández,

Colón-Reynoso,

Mazuela

2024

Agriculture

View full text Add to dashboard Cite

Greenhouses are instrumental in the advancement of regions globally. The geometric arrangement of these structures plays a pivotal role in governing sunlight distribution, facilitating ventilation, and managing condensation. The roof’s shape significantly affects energy efficiency and the accumulation of condensation water, which, when dripping onto crops, can induce diseases and diminish production. This study introduces a Matlab program designed for defining and analyzing greenhouse roof geometry that is adaptable to both single-span and multispan structures. Various roof shapes were examined, and angles along their length were determined to facilitate condensation droplet runoff. In the ogival roof shape, water droplets adhering to the roof surface were found to slide off, preventing interior dripping. However, in all semicylindrical roof structures, dripping occurred on more than 50% of the cultivated ground surface. Furthermore, the greenhouse’s energy efficiency was evaluated by analyzing diverse roof models, accounting for the surface area and internal air volume. There was little difference in the volume of air inside the greenhouse attributable to the roof shape. Increasing the arch height relative to the span width enhanced solar energy capture and the roof surface, with the semicylindrical shape being more efficient in this case. The results aim to aid in the selection of the optimal greenhouse type based on the climate and latitude. This study offers a valuable decision-making tool for the planning and design of agricultural structures, providing insights to enhance their overall sustainability and performance in diverse environmental contexts. Hence, in cold climates and high latitudes, the steeper roof angle of the ogival shape type 2l and its smaller surface area promote solar energy capture and reduce convective heat losses. In warmer climates, a larger roof surface facilitates natural cooling, making the ogival shape type 3l/2 recommended.

show abstract

A novel analytical solution for the transmissivity of curved transparent surfaces with application to solar radiation

El‐Maghlany

2016

Applied Thermal Engineering

View full text Add to dashboard Cite

Analytical study on solar energy absorbed on elliptic curved collector

Cited by 11 publications

References 17 publications

Geometric analysis of greenhouse roofs for energy efficiency optimization and condensation drip reduction

Geometric analysis of greenhouse roofs for energy efficiency optimization and condensation drip reduction

Geometric Analysis of Greenhouse Roofs for Energy Efficiency Optimization and Condensation Drip Reduction

A novel analytical solution for the transmissivity of curved transparent surfaces with application to solar radiation

Contact Info

Product

Resources

About