Greenhouse Design Research Articles

Implementation of greenhouse climate control simulator based on dynamic model and vapor pressure deficit controller

This paper discusses the implementation of greenhouse climate control simulator based upon dynamic model with intuitive user interface that provides various options to simulate greenhouse climate under open and closed loop control conditions. The simplified greenhouse climate model based upon mass and energy balance principle, encapsulates the realistic situations in a greenhouse to simulate and analyze the effect of different control strategies (shading, ventilation, cooling or heating) on inside climate for various greenhouse design configurations and under different weather conditions. The model is integrated with the proposed greenhouse-crop vapor pressure deficit (GH-crop VPD) based multi-input multi-output fuzzy climate controller that operates in feedforward mode and regulates greenhouse climate conducive for healthy plant growth and yield. Under closed loop operation, the controller automatically readjusts the operating status and rate of different climate control equipments (shade screen, roof vents, exhaust fan, cooling system and heating system) and simulates automatic control of GH-crop VPD within set limits irrespective of the variations in outside weather conditions. Designed as an educational tool, the simulator was used under open loop to demonstrate how for a selected greenhouse design and weather conditions, different climate control strategies affect greenhouse climate conditions. Multiple simulations run under different scenarios were simultaneously displayed for comparison study and analysis. Further, the closed loop simulations were performed that indicated high performance of the controller in regulating GH-crop VPD under different hot weather conditions and depicted what systems (rate and operating status of different climate control equipments) would be needed to meet desired conditions.

USE OF THE DELPHI EXPERT ELICITATION TECHNIQUE TO RANK FOOD SAFETY RISKS IN GREENHOUSE TOMATO PRODUCTION

One half of fresh tomato sales in the US are from greenhouse grown crops. Fresh tomato was linked to a number of foodborne disease outbreaks. Collectively, foodborne and phytopathogen hazards threaten both public health and economic viability of the greenhouse industry. Management practices in tomato greenhouses in North America were documented previously. In this study, a systematic, internet-based, iterative Delphi method was used to gauge opinions about the potential impact of various greenhouse management factors (water management, workers, environment and greenhouse design, equipment sanitation, animals, waste, and traceability) on food safety. The pretested questionnaire was distributed to 20 national and international experts in food safety of fresh fruits and vegetables. The Delphi process was repeated until the criteria for consensus were satisfied (expert agreement ≥70%). Expects attributed greenhouse irrigation water as a highly important source of contamination with human pathogens. Accordingly, testing of irrigation water for human pathogens was considered to be a valuable tool in controlling contamination in the greenhouse. According to this expert panel, people may occasionally introduce pathogens into the greenhouse. Hand washing and footwear were ranked the most effective in preventing contamination from employees and visitors. The majority of experts believed the presence of human pathogens in the greenhouse environment presented an important source of contamination for edible tomato fruits. Experts also agreed that livestock and poultry operations should be at least 250 feet away from the greenhouse. Although any animal intrusion was considered a high-extreme food safety risk-rodents were ranked the highest, and cats the lowest. Employee hygiene, mode of irrigation, equipment sanitation was ranked the most important management practice in prevention of contamination with human pathogens.

Preliminary Design of a Low-cost Greenhouse with Open Source Control Systems

Food security remains a global challenge, particularly in low-income countries. In Sub-Saharan Africa, one in four are undernourished, and the region has the highest prevalence of hunger in the world. Innovations in low cost greenhouse design have the potential to contribute to increased food security, particularly in areas where global climate change is creating additional variability in local weather patterns. This paper describes the preliminary design of a greenhouse that uses open source control systems. This design takes advantage of the decreasing cost and size of sensors to automate systems that have the potential to increase the efficiency and yield of greenhouses.

Which Design Constraints Apply to a Pipe-Framed Greenhouse?

Many studies related to greenhouse design have been conducted. This paper reviewed five results of research into the design of pipe-framed greenhouses (hereinafter pipe houses) using an investigation, numerical analysis and wind-tunnel test. The first and second studies showed how the pipe houses collapsed due to snow and wind load. The third study analyzed an economical and reasonable design for a typical pipe house subject to snow load. Seven numerical finite element models of simple pipe house were subject to stress and buckling analyses. In the fourth study, the distributions of wind pressure coefficient Cp, both external and internal, were evaluated in detail using a pipe-house model, based on a wind-tunnel experiment using 1:20 scale models in a turbulent boundary layer correctly simulating natural winds over typical open-country exposure. The fifth study investigated the effect of dp, the distance between the side walls of pipe houses, on the distribution of Cp on two or three pipe houses arranged in parallel. The results of these studies are indispensable to establish safe and economical pipe-house designs. Discipline: Agricultural engineering Additional key words: high tunnel, numerical analysis, snow load, wind pressure coefficient, windtunnel test

Evaluation of thermal behavior for an asymmetric greenhouse by means of dynamic simulations

In this paper is presented the design of an asymmetric greenhouse, with a simulation and evaluation of its microclimate by means of DesignBuilder®. Climatic and geographical conditions of the greenhouse location are processed with DesignBuilder®, which also allows to include the geometrical characteristics of the enclosure and its roofing, the properties of its building materials and a description of the climate control system. Three configurations of this asymmetric greenhouse are evaluated in order to analyze and compare their internal gains.

Design of Intelligent Greenhouse based on STC89C52

The growth of various crops requires specific environment. Intelligent greenhouse, can create the best external environment for the growth of all kinds of plant through regulation. In this study, intelligent greenhouse takes the single chip processor as the core, the design of temperature and humidity sensor is AM2301 of lian cheng chuang fa technology co, LTD. The system is mainly to complete the acquisition of scene temperature and humidity data; According to the actual needs of animal and plant growth to adjust litre cooling equipment, humidifying equipment, drop wet equipment and ventilation equipment, to provide the relatively controllable and even the most suitable temperature, humidity, light, water and other environmental conditions for animal and plant production, to create the most suitable small artificial environment for the growth of the plants and animals to meet the need of modern agriculture.

Estimation of wind load on a greenhouse and evaluation of its structural stability

Among all the loads that act on the greenhouse, wind load is the major one. In India, the basic wind speed varies from 33 to 55 m/s. Along with wind speed, wind load also depend on the geometry, height to width ratio, effective frontal area etc. So greenhouse design should be customized as per the localized wind load. 'One size fits all approach' in greenhouse design may leads to failure of the structure or being expensive. Unfortunately the standard for greenhouse design is lagging far behind in India. In this experiment, wind load for the double arch type naturally ventilated greenhouse was estimated as per IS code 875 (part 3) and IS 14462: 1997. The design wind pressure estimated to be 772 N/m 2 and wind load on the roof of the greenhouse is 222 kN (Suction) and 185 kN (Pressure). A model of the greenhouse is developed by means simulation with Finite Element Method using ANSYS 15.0 to test its stability at the calculated wind load. The truss and columns are studied with deflections and failure zones diagrams and possible failures were found out to redesign the elements.

Design and Development of Intelligent LED Plant Light Supplement System Based on Solar-Powered for Facility Agriculture

Intelligent LED plant light supplement system can improve and enhance plant photosynthesis, increase crop yields, especially for anti-season greenhouse cultivation in the facility agriculture.For the application of greenhouse crop cultivation, design and development of intelligent LED plant lights system based on solar-powered, the system uses solar photovoltaic power supply to save the cost and environmental protection. And using the digital control technology to achieve intelligent LED plant light supplement system control. The hardware and software design of system were described in detail in the paper, the experimental tested prototype was completed.The designed system has the advantages of energy saving, digital smart, green and efficient, etc., which suitable for promote the application of modern facilities agriculture.

Design and Implementation of Intelligent Greenhouses Based on the Internet of Things

With the development of modern agriculture construction, various types of supporting agriculture automation equipment began to use and achieved good economic benefits, at the same time, linkage, information transfer between the various devices become the bottleneck to limit the scale of agricultural production. In this paper, the research object, describes the control, the temperature in the greenhouse automation equipment in humidity control, ventilation system, irrigation system, automation equipment and its linkage, linkage alarm mechanism, the Internet of things technology control system model and the hardware and software realization scheme is given based on. Finally through the network implementation of the joint of various types of equipment and system control and alarm in the greenhouse, avoids some potential risks in agricultural production, saving the modern agricultural production cost and management cost.

Temperature Effect on Yield and Yield Components of Different Rice Cultivars in Flowering Stage

In order to study the effect of cold stress in flowering stage on yield and yield components of different rice cultivars, an experiment was performed as split plot factorial based on completely randomized design (CRD) in greenhouse of deputy of rice research institute of Iran (Amol) in 2010, in three repetitions. Treatment included 5 varieties as main factors that included cultivars of shirudi, fajr, local tarom, hybrid, and line 843. Two levels of temperatures T 1 (13°C, stress temperature) and T 2 (32°C, normal temperature, control) along with flowering stage were selected as two subfactors. Three seedlings were planted in each plot. The cold stress was done in flowering stage with holding pots at 13°C for 15 days. Results showed that low temperature had significant effect in level of 1 percent on all characters, such as the number of panicles, the length of panicle, and the number of full, empty, and total grains; as a result, yield had caused significant reduction. Interaction between temperature and varieties showed that most tolerant variety in relation to temperature stress along with least percentage yield (19%) is shirudi variety and the most sensitive one with most percentage of yield decrease (29%) was local tarom variety.

Modeling of simultaneous transfers of heat and mass in a trapezoidal solar distiller

A model of heat and mass transfer phenomena in a trapezoidal cavity is established. This work is partly based on the experimental results obtained in the case of a trapezoidal-shaped solar distiller. The resolution of the related system of equations gives results that are in a good agreement with those obtained experimentally. The modeling was made on the basis of a stagnant zone within the closed cavity, whose walls are at different temperatures. The numerical simulation could contribute to the study and design of numerous applications such small solar distillation units, solar driers and solar greenhouses, among others.

GREENHOUSE DESIGN FOR VEGETABLE PRODUCTION IN SUBTROPICAL CLIMATE IN TAIWAN

ISHS International Symposium on New Technologies for Environment Control, Energy-Saving and Crop Production in Greenhouse and Plant Factory - Greensys 2013 GREENHOUSE DESIGN FOR VEGETABLE PRODUCTION IN SUBTROPICAL CLIMATE IN TAIWAN

SYSTEM INTEGRATION AND OPTIMIZATION MODEL (SIOM)

Modern high tech greenhouses are a combination of various technical systems. There are more and more interactions between those systems. Therefore it is hard to adapt greenhouse design to another climate/situation. There is a need for a decision support system, combining practical know how, local parameters, available design models and validation data. This decision support system should also support growers in optimizing their business case. A publish/subscribe framework originally designed for urban planning is adjusted for the greenhouse design application. Design models such as climate, light, economy, crop growth are connected to this framework. In a case study the functioning of the framework is illustrated. The publish/subscribe framework is an easy way of connecting a wide range of existing design models. It requires low maintenance, several models with different abstraction level can be connected and models can be exchanged easily. The publish/ subscribe approach allow parallel processing, speeding up calculation time. SIOM is an effective approach to combine knowledge stored in various design models and gives an end user insight in the consequences of their design choices. Validation of the results, additional design models and a design process scheme is needed to make SIOM applicable by greenhouse builders.

Analysis of Working Load based on Wind and Snow Load for Greenhouse Foundation

This study analyzed load transferred from upper structure due to wind and snow loads and applied to foundation on greenhouse structure in order to provide basic data for economic and reasonable design of greenhouse. The results indicate that the upper structures of greenhouses in Korea take wind load of 18.2-121.5 kgff/m2 and snow load of 3.1-104.6 kgff/m2. The maximum compressive load from axial direction applied on the foundation of greenhouse subjected to facility and crop loads was 437 kgff. The maximum pull-out load applied on the foundation of greenhouse subjected to wind load was 1557 kgff. The maximum compressive load applied on the foundation of greenhouse subjected to snow load was 6094 kgff.

Experimental study of an air conditioning system to control a greenhouse microclimate

In this papper, a thermal model is developed to investigate the possibility to use the ground thermal energy for the greenhouse heating or cooling. A control system of the ground heat storing is integrated in a chapel greenhouse located in the premises of the Technology and Research Energy Center, Tunis, Tunisia. Polypropylene capillary heat exchangers, suspended in the air and buried into the ground of the greenhouse, are used to store or destore solar energy excess. During the day, the air-suspended exchangers recuperate the solar energy in excess. This recuperated energy is then stored into the ground through the buried exchangers. At night the stored thermal energy is brought back by the suspended exchangers to heat the greenhouse air. The purpose of this study is to contribute in the greenhouse microclimate control. In order to maintain the greenhouse air temperature at 20°C, suitable for a defined agriculture, the solar energy and the cold water are respectively used for heating and cooling the greenhouse inside air. The design and construction of a chapel greenhouse equipped with the control system is carried out. The studied system is used, at the same time for; heating, cooling the greenhouse air and storing the solar energy in excess.Experiments were conducted during the years 2012–2013, to evaluate the effectiveness of the control system achieved. The measured values of the greenhouse air temperatures with and without the control system are discussed.

SERASİM: 3-Boyutlu Akıllı Sera Tasarım Programı

Greenhouse construction projects need to consider local climate characteristics, production type in the greenhouse and materials used for the physical structure and glazing. A major share of commercial greenhouse manufacturers in Turkey produce turnkey greenhouse projects either using by trial and error method or imitating/reproducing greenhouse imported from other countries. Improperly designed projects may result in greenhouses having weak construction or more expensive structures due to using unnecessarily larger profiles which consequently cause a loss the profits for the growers. This study aims to contribute to the improvements and overcome the gaps in practice of greenhouse projects by designing a software for an expert system that utilizes an accurate Project considering them and mandatory buildings standards of Turkish Standardization Institute (TSE). The expert system, named SERASİM, has been developed within the framework of the present MSc. Thesis and enables calculating each part of the construction system of a gable roof glass house according to TSE standards. Besides calculations for statics, dynamics and strength as well estimating the bill of quantity, SERASİM can be utilized to determine the heating requirements and costs for selected locations and crops. SERASİM may also be used as a teaching tool for courses including greenhouse design, protected cultivation and greenhouse acclimatization.

Greenhouse Design: An Engineering Unit

Greenhouse Design: An Engineering Unit

Thermal Environment of Chinese Solar Greenhouses: Analysis and Simulation

<abstract> <bold><sc>Abstract. </sc></bold>Chinese solar greenhouse is the most common protected horticulture facility in China. The design of solar greenhouses has been evolving but few designs were based on solid engineering analyses and extensive field testing. This article analyzed three aspects that contribute to their good thermal performance: high solar transmittance of the South facing roof due to limited structural and equipment shading, interception and heat buffering of solar radiation by opaque walls and ground, and good insulation of the North facing roof, wall, and sidewalls. A mathematical model is presented to predict and evaluate the thermal environment of solar greenhouses. The model is based on the heat balance and the heat exchange between the system components. Simulations and analyses using the solar greenhouse model suggest the following: 1) materials with good heat insulation should be used for the outer layer of walls, and those with high thermal conductivity and volumetric specific heat should be used for the inner layer, 2) the gained benefits in terms of air temperature and heat flows released from walls to the inside air start to become marginal as the wall thickness increases, and3)by lowering indoor ground the thermal environment of solar greenhouses can be greatly improved. An optimal wall thickness can be determined by weighing the improvements of the thermal environment against the increase in cost associated with material selection and construction.

EFFECT OF ANABAENA VAGINICOLA INOCULUM ON GROWTH OF POT PLANTS

Although much attention has been paid to study of nitrogen fixation by blue-green algae in paddy fields, algae are also beneficial for plant by producing plant - growth promoters like auxins, cytokinins, abscisic acid and ethylene. Monoalgal cultures was carried out by growing the isolates in nitrate free BG-11 medium in two liter container at 24° and a 12/12 h light-dark cycle at artificial illumination (2,000-2,500 Lux) with constant stirring and aeration. After three weeks culture was harvested and used as an inoculum. Five healthy seedlings were grown in 1 liter pots (14 cm diam.) including 60% peat, 25% sand and 15% normal soil. No fertilizer was applied, but 400 milliliters algal suspension (OD=0.3) was sprayed on treated and BG-11 medium for untreated pots. The pots were arranged in a completely randomized design in an experimental greenhouse. Growth of plants was evaluated by measuring plant height, root length, number leaf and flowers after 50 days planting. From the results described in this paper, it is clearly showed that the algal culture contained some substances that can promote growth of the plants. Result of this finding also has led to the recognition that addition of algal inoculums positively affected plant height and plant root length.

NUMERICAL SIMULATION OF THE AIRFLOW AND TEMPERATURE DISTRIBUTION IN A CLOSED EMPTY VENLO GLASSHOUSE UNDER HOT AND ARID CLIMATE

The thermal behavior of the inside air of a closed Venlo glasshouse without plants was analysed under semi-arid climate conditions. The aim of the study was to investigate to what extent the characteristics of the greenhouse design and outside climatic conditions influence airflow and temperature patterns inside the greenhouse. For the purpose of the present work, a CFD modeling approach was combined with field surveys. The study focuses on the effects of (i) the thermal inertia of the soil, (ii) the movement of the interior air, and (iii) the distribution of the temperature inside the greenhouse. Two contrasted days were considered: a windy overcast day and clear day. From the results, it is concluded that when the greenhouse is fully closed with bare soil, the heat absorbed and stored by the ground during daytime represents a significant heat source which enhances buoyancy forces, the main driving forces of the movement of the air, especially during the night. The temperature of the roof was relatively low and the air temperature distribution inside the greenhouse disclosed a vertical gradient from the roof towards the ground surface due to the movement of the air above the surface of the ground absorbing thermal energy (solar energy). Maximum air velocities inside the greenhouse were observed near the ground surface, while they reached their minimum values in the middle of the greenhouse. Similar results were obtained for the windy overcast day and for the clear day.