Applicability of Solar Evaporative Cooling in Greenhouses productivity Improvement

Merabti, Leila; Abbas, Mohamed A.; Taane, Walid

doi:10.1109/irsec48032.2019.9078261

Cited by 3 publications

(1 citation statement)

References 1 publication

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“…The wind-solar energy hybrid has been researched for use in transportation but has not yet been fully developed (Merabti et al, 2019). Most of the previously performed wind turbine modelling has been either through MATLAB Simulink or Computational Fluid Dynamics (CFD).…”

Section: Integration Of Renewable Energy On Cooling Technologies and ...mentioning

confidence: 99%

Wind power generation and integration into a low-cost fresh produce preservation technology: a case of a renewable energy integration into an evaporative cooling system.

Mthethwa

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Smallholder farmers in developing countries experience high-postharvest losses (PHL) estimated around 23% during the transportation of fruit and vegetables. This is due to the inappropriate storage facilities that are unable to maintain optimum environmental conditions which are specific to the fresh produce. This situation arises because smallholder farmers cannot afford the available mobile cooling technologies such as refrigerated trucks since they are energy-intensive which makes them have high running costs in addition to the associated high investment costs. Consequently, smallholder farmers resort to utilizing small vehicles to transport fresh produce without air conditioning to cool the environment. These vehicles usually have an environment mainly characterized by high temperature and low relative humidity which are undesirable conditions for fresh produce. The power supply is a great challenge for mobile cooling technologies. As the main energy source, mobile cooling technologies use petrol and diesel to power the systems. These energy sources are costly, rapidly depleting, and detrimental to the atmosphere. Renewable energy sources such as biomass, solar and wind energy are promising technologies to substitute fossil fuels to power cooling technologies. Using renewable energy sources reduces the high incurring costs of operating a cooling technology, which ultimately reduces the purchase or lease costs. Since there is high airflow on the road associated with moving vehicles, this study aims to design and develop a small wind turbine to power an evaporative cooling system (ECS) during the transportation of fruit and vegetables in KwaZulu-Natal. The design of the wind turbine is done with the assistance of the Blade Element Momentum (BEM) theory, QBlade and MATLAB Simulink modelling software. A prototype of the wind turbine was designed, developed and tested on a moving vehicle between Pietermaritzburg and Estcourt. The wind turbine is 600 mm in diameter and made of three PVC pipe material blades connected by a 60 x 2 mm diameter mild steel plate hub protected by an 800 x 800 x 500 mm mild steel protective casing.The wind turbine was tested against three vehicle speeds of 60, 80, and 100 km.h -1 , and the two opening levels, level 1 at 45° and level 2 at 80° relative to the louvre mechanism frame. The results of this study revealed that the power output is significantly influenced (p<0.001) by both the vehicle speed and louvre opening level. The power output of 113.4, 159.6 and 210.0 W per hour was observed for the vehicle speed of 60, 80 and 100 km.h -1 , respectively, on louvre opening level 1. Further, the power output of 142.8, 268.8 and 294.0 W per hour was observed for a wind speed of 60, 80, and 100 km.h -1 , respectively on louvre opening level 2. This shows iv that higher wind speeds (vehicle speeds) obtain higher power output which account for the small size of the wind turbine rotor. The maximum power of 294 W was obtained at a vehicle speed of 100 km.h -1 (27.78 m.s -1 ), for louvre opening l...

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Section: Integration Of Renewable Energy On Cooling Technologies and ...mentioning

confidence: 99%

Wind power generation and integration into a low-cost fresh produce preservation technology: a case of a renewable energy integration into an evaporative cooling system.

Mthethwa

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Selection criteria of cooling technologies for sustainable greenhouses: A comprehensive review

Tawalbeh

Aljaghoub

Alami

et al. 2023

Thermal Science and Engineering Progress

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Modifying Walk-In Tunnels through Solar Energy, Fogging, and Evaporative Cooling to Mitigate Heat Stress on Tomato

Sharaf-Eldin

Yaseen‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬

Elmetwalli

et al. 2023

Horticulturae

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Global warming is by far the most significant issue caused by climate change. Over the past few decades, heat stress has intensified into a serious issue that has a negative impact on crop production. Hence, it is crucial to modify cultivation systems to cope with this kind of stress, particularly in arid dry regions. In comparison to open-field cultivation, tomato production under protected cultivation techniques in walk-in tunnels that are suited for different farmers’ financial abilities was evaluated during the late summer season. The studied tunnels included a shaded net tunnel with natural ventilation, net tunnel with a fogging system and plastic tunnel with evaporative cooling (wet pad and fans). For the operation of fogging and evaporative cooling systems, solar energy was used as a sustainable, eco-friendly energy source. The results indicated that the solar energy system successfully operated the studied cooling systems. All studied protective cultivation techniques mitigated heat stress on tomato plant and improved the microclimate under walk-in tunnels. Moreover, evaporative cooling and fogging systems significantly increased plant leaf area, cell membrane efficiency and the contents of chlorophyll, relative water and proline compared to the net tunnel with natural ventilation. Furthermore, a marked reduction in physiological disorders was noticed. Improved physiological and biochemical parameters and limited physiological diseases led to higher fruit set, marketable fruit yield and total productivity. The percentage of marketable fruit yield increased by around 31.5% with an evaporative cooling system, 28.8% with a fogging system and 17% with a shaded net tunnel with no positive cooling as compared to an open field. However, the plants grown in open-field cultivation without protection significantly deteriorated from heat stress and had a high incidence of physiological disorders. The most incident physiological disorders were blossom-end rot, cracking, internal white tissues, sunscald, puffiness, blotchy ripening, cat face and exserted stigma. It is recommended to use a solar energy system to modify microclimate conditions through fogging or evaporative cooling under walk-in tunnels to ameliorate heat stress on grown tomato in the late summer season for higher fruit yield and fewer physiological disorders.

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Applicability of Solar Evaporative Cooling in Greenhouses productivity Improvement

Cited by 3 publications

References 1 publication

Wind power generation and integration into a low-cost fresh produce preservation technology: a case of a renewable energy integration into an evaporative cooling system.

Wind power generation and integration into a low-cost fresh produce preservation technology: a case of a renewable energy integration into an evaporative cooling system.

Selection criteria of cooling technologies for sustainable greenhouses: A comprehensive review

Modifying Walk-In Tunnels through Solar Energy, Fogging, and Evaporative Cooling to Mitigate Heat Stress on Tomato

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