Progress, problems and prospects for standardization of greenhouse-related technologies

Ren, Yuanhang; Wang, Minjuan; Saeeda, Iftikhar Ahmed; Chen, Xuerui; Gao, Wanlin

doi:10.25165/j.ijabe.20181101.3857

Cited by 7 publications

(3 citation statements)

References 16 publications

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“…The current design method for a multi-span greenhouse is based on the single greenhouse as a basic unit. And the multi-span greenhouse is designed to be assembled by several single greenhouses [67] . However, induced flows and pressures on multi-span greenhouses are different from those on a single-span greenhouse [68] .…”

Section: Influence Of Span Number On Wind Pressurementioning

confidence: 99%

Wind pressure acting on greenhouses: A review

Nan¹,

Wang²,

Bai³

et al. 2021

International Journal of Agricultural and Biological Engineering

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Greenhouses are widely used in agricultural and horticultural production. With the characteristics of lightweight, small stiffness and high flexibility, greenhouses are sensitive to wind loads. In the calculation of wind loads, the wind pressure coefficient (Cp) is essential. The rationality of the value directly affects the safety and economy of greenhouses. Therefore, the Cp values estimation is one of the most important issues in the design of greenhouses. In order to make full use of the existing research results, in this study, three main methods for estimating Cp values were analyzed, namely, full-scale field experiment, wind tunnel experiment and numerical simulation. Five factors influencing the Cp values were then reviewed including greenhouse design parameters, greenhouse group, overhanging eaves, ventilation and wind direction. Based on the existing researches, suggestions for future development and research work were also put forward. Owing to the flexibility and deformability of greenhouses, the fluid-solid coupling method should be used to analyze the effects of vibrations on wind pressures. The interaction of building parameters (such as the number of spans, ridge height, roof shape and slope angle) and terrain around the greenhouse should be taken into consideration comprehensively. The destructive vortices occurred on the greenhouse should be further investigated.

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Section: Influence Of Span Number On Wind Pressurementioning

confidence: 99%

Wind pressure acting on greenhouses: A review

Nan¹,

Wang²,

Bai³

et al. 2021

International Journal of Agricultural and Biological Engineering

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show abstract

“…It could maintain high interior air temperature without or with a little amount of heating [1,2] . However, this type of greenhouse has the flaws of high construction cost, low land utilization efficiency, narrow space, etc [3,4] . As a result, a large-scale plastic tunnel with an external thermal blanket (LPTEB) has been employed in recent years to address the above issues.…”

Section: Introduction mentioning

confidence: 99%

Performances of an air thermal energy utilization system developed with fan-coil units in large-scale plastic tunnels covered with external blanket

Zong

Xiao

Song

et al. 2022

International Journal of Agricultural and Biological Engineering

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To improve the problem of low temperature at night in winter due to the lack of thermal storage in large-span plastic tunnels, an air thermal energy utilization system (ATEUS) was developed with fan-coil units to heat a large-scale plastic tunnel covered with an external blanket (LPTEB) on winter nights. The ATEUS was composed of nine fan-coil units mounted on top of the LPTEB, a water reservoir, pipes, and a water circulation pump. With the heat exchange between the air and the water flowing through the coils, the thermal energy from the air can be collected in the daytime, or the thermal energy in the water can be released into the LPTEB at night. On sunny days, the collected thermal energy from the air in the daytime (E c ) and released thermal energy at night (E r ) were 0.25-0.44 MJ/m 2 and 0.24-0.38 MJ/m 2 , respectively. Used ATEUS as a heating system, its coefficient of performance (COP), which is the ratio of the heat consumption of LPTEB to the power consumption of ATEUS, ranged from 1.6-2.1. A dynamic model was also developed to simulate the water temperature (T w ). Based on the simulation, E c and E r on sunny days can be increased by 60%-73% and 38%-62%, respectively, by diminishing the heat loss of the water reservoir and increasing the indoor air temperature in the period of collecting thermal energy. Then, the COP can reach 2.6-3.8, and the developed ATEUS can be applied to heating the LPTEB in a way that conserves energy.

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“…There are some incorporating features of plant factories, such as artificial lighting and active cooling, particularly on the excellent hermetic seal, tunable light intensity, forced circulation channels of internal air, and high CO 2 absorption rate [2] . Currently, the switching control system is commonly used to manipulate the artificial lighting, temperature, humidity, CO 2 concentration, and nutrient solution in most facilities of plant factories [3][4][5][6] . However, the input and output signals of various parameters always vary in constant impulse [7][8][9] , easily resulting in power loss and annual maintenance cost of the equipment [10] .…”

Section: Introduction mentioning

confidence: 99%

Modeling and simulation of temperature control system in plant factory using energy balance

Zhang

Chen³

et al. 2021

International Journal of Agricultural and Biological Engineering

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Closed production systems, such as plant factories and vertical farms, have emerged to ensure a sustainable supply of fresh food, to cope with the increasing consumption of natural resource for the growing population. In a plant factory, a microclimate model is one of the direct control components of a whole system. In order to better realize the dynamic regulation for the microclimate model, energy-saving and consumption reduction, it is necessary to optimize the environmental parameters in the plant factory, and thereby to determine the influencing factors of atmosphere control systems. Therefore, this study aims to identify accurate microclimate models, and further to predict temperature change based on the experimental data, using the classification and regression trees (CART) algorithm. A random forest theory was used to represent the temperature control system. A mechanism model of the temperature control system was proposed to improve the performance of the plant factories. In terms of energy efficiency, the main influencing factors on temperature change in the plant factories were obtained, including the temperature and air volume flow of the temperature control device, as well as the internal relative humidity. The generalization error of the prediction model can reach 0.0907. The results demonstrated that the proposed model can present the quantitative relationship and prediction function. This study can provide a reference for the design of high-precision environmental control systems in plant factories.

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Progress, problems and prospects for standardization of greenhouse-related technologies

Cited by 7 publications

References 16 publications

Wind pressure acting on greenhouses: A review

Wind pressure acting on greenhouses: A review

Performances of an air thermal energy utilization system developed with fan-coil units in large-scale plastic tunnels covered with external blanket

Modeling and simulation of temperature control system in plant factory using energy balance

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