Greenhouse Design Research Articles

DEVELOPMENT OF A GREENHOUSE SYSTEM FOR TROPICAL LOWLAND IN INDONESIA

Wageningen UR - A&F (former IMAG) developed together with Plant Research International (PRI) and the Dutch industries Rovero Systems B.V. and Plasthill B.V. and the Indonesian company PT East West Seed Indonesia a new greenhouse system for the production of high quality horticultural products in the tropics. In this study plastic-covered greenhouses are designed which are particularly adapted to the regional circumstances of tropical lowland in Indonesia. The greenhouse design has enough resistance against local wind loads, has high natural ventilation, but is at the same time mainly closed for insects by using insect nets. The airflow and the temperatures in the greenhouse are simulated by CFD software during design stage to optimize greenhouse size, shape and the ventilation openings. A new plastic film covering is developed. The new covering consists of a 200 µm polyethylene film with a lifetime of about 3 years in Indonesia. The film contains a UV-block pigment and has highly light diffusing properties. Additionally film prototypes are developed, which selectively reflect near infrared radiation (NIR) with the objective to reach a cooling effect inside the greenhouse. Six identical greenhouse prototypes are produced in The Netherlands and built in the isle of Java in Indonesia in spring 2003. In the greenhouses tomatoes are cultivated and observed. Additionally climate measurements are carried out to evaluate the new designed greenhouses.

DETERMINATION OF THE OPTICAL PROPERTIES OF PLASTIC FILMS USED AS CLADDING MATERIALS IN NOVEL ENERGY EFFICIENT GREENHOUSES

ISHS International Symposium on Greenhouses, Environmental Controls and In-house Mechanization for Crop Production in the Tropics and Sub-Tropics DETERMINATION OF THE OPTICAL PROPERTIES OF PLASTIC FILMS USED AS CLADDING MATERIALS IN NOVEL ENERGY EFFICIENT GREENHOUSES

Greenhouses in extreme environments: The Arthur Clarke Mars Greenhouse design and operation overview

Since its deployment on Devon Island, Canadian High Arctic, in 2002, the Haughton Mars Project’s Arthur Clarke Mars Greenhouse (ACMG) has supported extreme environment related scientific and operation research that is relevant to Mars analogue studies – each at a specific level of fidelity and complexity. The Greenhouse serves as an initial experimental test-bed supporting field research, from which lessons may be learned to support the design and implementation of future field facilities, and enabling higher fidelity demonstrations. This paper provides an overall description of the ACMG, describes the different subsystems, explains its operational modes, details some results over the three years of operation and discusses future development plans.

GREENHOUSE DESIGN APPLYING CFD FOR INDONESIAN CONDITIONS

In the design phase of a test site in Indonesia computational fluid dynamics has been used to design the construction of the plastic greenhouse. Greenhouses in Indonesia are built to protect the crop from heavy rain and insects. The climate in four different greenhouse designs is calculated without insect gauze and with two types of insect gauze in the openings. Two designs consist of greenhouses with a top opening at one side of the ridge, with different dimensions of the top opening. The third design has no top opening, and the fourth design is the conventional Indonesian design consisting of three spans with an opening on one side of the ridges. The walls of the greenhouses are open or covered by insect gaze. The ground area in the greenhouse is equal for all designs. The ventilation rate and the maximum temperature in the greenhouse have been used to evaluate the designs. The influence of the wind speed and direction has been investigated. The design without an opening in the top has the highest ventilation rate and the lowest maximum temperature in case of wind due to aerodynamics. In case of no wind the climate in the design without top ventilation is slightly worse than in the other designs. Increasing the length of the greenhouse reduces the ventilation for this design. The insect gauze reduces the ventilation by more than 50%. Based on these results a new design has been developed with an aerodynamic top opening. This design proved to function with and without wind. This design is currently being tested in Indonesia.

MICROCLIMATE AND ENERGY CONSUMPTION IN COMMERCIAL, HOT-WATER AND STEAM HEATED GREENHOUSES FOR TOMATO PRODUCTION

MICROCLIMATE AND ENERGY CONSUMPTION IN COMMERCIAL, HOT-WATER AND STEAM HEATED GREENHOUSES FOR TOMATO PRODUCTION

PREDICTION OF THE EFFECT OF INSECT-PROOF SCREENS ON CLIMATE IN A NATURALLY VENTILATED GREENHOUSE IN HUMID TROPICAL CLIMATES

The impact of different types of insect-proof screens on greenhouse climate in humid tropics needs to be quantified in order to develop technically and economically optimal greenhouse constructions. Thus, physical properties of various insect-proof screens were determined in the laboratory at the Institute of Horticultural and Agricultural Engineering, University of Hannover, Germany. Specially adapted experimental greenhouses were built at AIT campus in Bangkok, Thailand. A dynamic energy and mass balance model of the greenhouse system was developed to predict the greenhouse climate from external weather data and properties of insect screens. Scenario simulations were carried out to predict the effect of screen properties on greenhouse climate. External and greenhouse climate measurements were made in Bangkok. The internal climate measurements were carried out concurrently in two similar, naturally-ventilated greenhouses covered with different insect-proof screens on ventilation openings. Tomato (Lycopersicon esculentum ‘King Kong II’) plants were grown in the greenhouse during the experimental period. Model predictions of greenhouse air temperature were compared to measurements from the two greenhouses and good agreement was achieved. The results form a good basis for decisions on screened greenhouse design improvements and climate control interventions in screened greenhouses in the humid tropical climates. INTRODUCTION Although temperatures and global radiation are very suitable for vegetable cultivation throughout the year in the humid tropics, open air cultivation is hindered by heavy rainfall and high humidity which cause crop damage and infestation by diseases. High incidence of pests such as thrips and aphids is also a big problem. Therefore, greenhouse systems which can provide the optimal plant growth environment while offering maximum protection against pests need to be developed. According to von Zabeltitz (1993), air temperature and air humidity should not be higher in tropical greenhouses than in the open air. Cooling-related expense is one of the most important greenhouse operation costs in the humid tropics. But the efficiency of fan and pad cooling systems in greenhouses in the humid tropics is limited due to high humidity of ambient air (H-J. Tantau, pers. commun., 2004). It is also expensive. Naturally-ventilated greenhouses can result in saving of cooling-related costs. Physical exclusion of pests through the use of insect-proof screens on greenhouse ventilation openings is an increasingly popular way of reducing pesticide applications. A consequence of the use of insect-proof screens is that they restrict air-flow and thus affect the climate in the greenhouse. The effect of insect-proof screens on greenhouse climate depends on the physical properties of the screens (i.e. discharge coefficient and spectral transmissivity) and the ratio of the screen area to floor area. Different authors have reported different values of discharge coefficients of greenhouse openings (Sase and Christianson, 1990; Montero et. al. 1997; Munoz et. al. Proc. IC on Greensys Eds.: G. van Straten et al. Acta Hort. 691, ISHS 2005 45

CFD PREDICTION OF THE NATURAL VENTILATION IN A TUNNEL-TYPE GREENHOUSE: INFLUENCE OF WIND DIRECTION AND SENSIBILITY TO TURBULENCE MODELS

ISHS International Conference on Sustainable Greenhouse Systems - Greensys2004 CFD PREDICTION OF THE NATURAL VENTILATION IN A TUNNEL-TYPE GREENHOUSE: INFLUENCE OF WIND DIRECTION AND SENSIBILITY TO TURBULENCE MODELS

Simulation of Greenhouse Management in the Subtropics, Part II: Scenario Study for the Summer Season

Adaptation of a greenhouse climate management strategy to local climate conditions is important for the improvement of resource use efficiency of greenhouse crop production. In this paper the optimal greenhouse climate management under hot, humid, subtropical summer conditions was investigated through simulation analysis based on the Greenhouse Process (KASPRO) model, previously validated under this particular conditions. The study was limited to affordable means of greenhouse design, crop and climate management such as ventilation capacity, canopy size and whitewashing, in a greenhouse without injection of carbon dioxide. Obviously, the increase of greenhouse ventilation capacity leads to an increase of carbon dioxide concentration in the greenhouse air, canopy transpiration, and thus evaporative cooling of the greenhouse air and crop canopy, and in turn to an increase of crop biomass production. The results show, however, that there is a rather sharp ceiling beyond which there is little gain in increasing ventilation capacity. For a cucumber crop under the summer conditions typical of Shanghai, the ventilation capacity of the greenhouse should be about 40 volume changes per hour. The balance of assimilation, respiration and evaporative cooling ensure that crop biomass production is maximal at a canopy leaf area index of 4.

Numerical model of the three-dimensional isothermal flow patterns and mass fluxes in a pitched-roof greenhouse

The three-dimensional isothermal flow patterns and mass fluxes in a full-scale, pitched-roof, single-span greenhouse were numerically resolved, and data from tests on a full scale were used to validate the code, the inlet boundary conditions and the greenhouse design grid method. For numerical solution of turbulent flow, a high-Reynolds-number k–ε model is suitable. Computational domain sizes were selected so as to fulfil the requirements of free-stream conditions whilst ensuring that grid geometrical characteristics satisfy the physical limitations of the standard k–ε model. A special feature of a case of a wind blowing parallel to a ridge (0°) is that the flow in the leeward half of the greenhouse comprises two vortexes with opposite senses of rotation, which bring in air mass through the vents and deliver it to the windward half. A spiral type of flow was found for winds blowing at 15–75° to the ridge direction: part of the air enters via the windward wall vent near the leeward gable-wall and emerges through the leeward roof vent near the windward gable-wall.Mass fluxes and flow patterns on wind direction, and on the opening angles of the windward and leeward vents. Thus, the ventilation rate induced by a wind directed perpendicularly to the greenhouse ridge is 4–4.9 times as great as that induced by a wind parallel to the ridge. A ventilation rate of a simulated greenhouse type was found to be significantly less responsive to a change in wind direction from 45° to 90° than to one from 0° to 45°. Present numerical results are in good agreement with those of other experiments and observations.

GREENHOUSE DESIGN FOR THE FUTURE WITH A CLADDING MATERIAL COMBINING HIGH INSULATION CAPACITY WITH HIGH LIGHT TRANSMITTANCE

For the world exhibition Floriade 2002 in The Netherlands a greenhouse design is developed by IMAG together with General Electric Plastics, Bergen op Zoom with polycarbonate double-web sheets with a zigzag-shaped surface. Intensive research was completed to develop the special zigzag shape of the plastic sheets resulting in an enhanced light transmittance and energy saving of approximately 20% over the whole year. The optimal dimensions for the sheets with respect to light transmittance, strength and insulation is a pattern of 50 mm for the zigzag shape, a thickness of 25 mm and the inclination of the pattern is 50°. The transmittance for diffuse light of the entire greenhouse with the double-web sheets is 78.8%.

Design Suggestions and Greenhouse Management for Vegetable Production in Perlite and Rockwool Media in Florida

The purpose of this publication is to present suggestions and options for designing and operating a greenhouse for vegetable production in solid media systems. While developed through perlite and rockwool research, these recommendations also would apply to other solid media, such as peat, pine park mixes or coco fiber. The major design considerations are those pertaining to the floor design for the media system and irrigation system design. Suggestions also are presented for general greenhouse design and operation for tomato culture. Many of these design and management suggestions would apply to houses with other production systems, e.g., upright bag or peat-trough, and in most cases would be applicable for cucumbers, eggplant, and pepper. First published Oct. 1990.

Effect of greenhouse design parameters on conservation of energy for greenhouse environmental control : Gupta, M. J. and Chandra, P. Energy, 2002, 27, (8), 777–794

Effect of greenhouse design parameters on conservation of energy for greenhouse environmental control : Gupta, M. J. and Chandra, P. Energy, 2002, 27, (8), 777–794

SE—Structures and Environment: Convective and Ventilation Transfers in Greenhouses, Part 2: Determination of the Distributed Greenhouse Climate

In this paper, the characterisation and modelling of the most relevant convective transfers contributing to the description of the distributed greenhouse climate are studied in detail. After a brief review of the equations governing flows within the greenhouse, the major theoretical approaches are recalled. The focus is on the study of the distributed climate which requires the equations governing the fluid flow and includes the turbulent transfer. The digitisation of these equations and their solution using computer fluid dynamics (CFD) software are presented. The measurement techniques associated with this approach are also presented, with special attention paid to the determination of air flows and climate patterns using advanced flow measurement techniques such as particle imagery visualisation (PIV) and sonic anemometry. A complete panorama of the studies pertaining to air movement inside the various greenhouse types is presented and it is particularly focused on recent studies dealing with plant–air interactions, particularly the leaf boundary layer climate and the air flows within the crop canopy. Despite the difficulties of modelling turbulent transfers, it is shown that simulations involving CFD software are becoming more realistic and able to describe with good accuracy the main features of the distributed climate inside the greenhouse. The major consequences of this progress are discussed with respect to improvement of the greenhouse climate through better plant protection and enhancements of greenhouse design and control.

Effect of greenhouse design parameters on conservation of energy for greenhouse environmental control

A mathematical model was developed and used to study the effect of various energy conservation measures to arrive at a set of design features for an energy efficient greenhouse. The Simulation results indicated that under cold climatic conditions of northern India, a gothic arch shaped greenhouse required 2.6% and 4.2% less heating as compared to gable and quonset shapes. An east–west oriented gothic arch greenhouse required 2% less heating as compared to a north–south oriented one. North wall insulation of an east west oriented gothic arch greenhouse saved 30% in heating costs. The use of night curtains reduced the night time heating requirement by 70.8% and daily requirement by 60.6%. By replacing the single cover on the southern side with air inflated double wall glazing, the heating requirement was reduced by 23%. The combination of the design features for an energy efficient greenhouse suitable for cold climatic conditions was found to reduce the greenhouse heating needs by 80%. An internal rock bed thermal storage/retrieval system met the remaining heating energy requirements of the energy-conserving greenhouse.

A review of greenhouse engineering developments during the 1990s

The paper begins with a brief review of earlier work. The 1990s saw limited extensions to the theory, computer modelling and practices relating to light transmission, apart from an interesting, but unproven new design to improve transmission. Studies concentrated on improving the performance of greenhouse elements (e.g. cladding), including methods of measurement. Thermal studies show significant progress. Computer modelling was extended to include the time dimension and finite element techniques were used to improve resolution of detail. As with light transmission, studies intended to improve the quality of greenhouse elements were also carried out. Understanding and modelling the performance of a thermal screen has also been improved, both as such and as an integral part of the greenhouse. Much effort was directed towards understanding ventilation. Analysis has shown that different sources exist (thermal-, wind-induced), and these have been analysed. The existence of internal circulating air patterns has also been established. The optimisation of carbon dioxide concentrations in greenhouses has now reached the point where the gain to a grower can be readily predicted. Further computer modelling of light transmission to include the effects of scattering and modelling of skylight to predict leaf irradiance are proposed. Extension of finite element techniques to further improve resolution in thermal studies is recommended. A comprehensive investigation of the physical and engineering aspects of ventilation and internal air flows is also needed, to support the extended thermal studies of the greenhouse. Finally, a pilot study, anticipating the design of a computer-controlled greenhouse is envisaged.

Wind pressures on permeably and impermeably-clad structures

The first European Standard for the design of commercial-production greenhouses passed through the formal voting stage in 2000 and its publication is imminent. For structural design considerations, it is based on the Eurocodes, and so for wind loading it is based on ENV 1991-2-4: 1995, although it provides additional information where specific data are available. During the drafting exercise, one deficiency identified in available wind loading information was that of pressure coefficient data for permeably clad structures. Greenhouses, particularly flat shading structures and curved roof houses, are often clad in permeable shade or insect-proof netting in southern Europe to reduce solar radiation gain and to increase ventilation. To facilitate reliable design of such structures, pressure data were obtained from large-scale tests conducted in the Jules Verne climatic wind tunnel at CSTB, Nantes, in November 1999. This paper reports the experiments conducted on an arch structure and on a flat-roof structure, where each was clad in turn in an impermeable plastic film, an ‘insect net’ of 33% open area, and a ‘shade net’ of 39% open area. The pressure coefficient data obtained with each cladding are compared for each of the two structural forms.

Residues of methamidofos, malathion, and methiocarb in greenhouse crops.

The diminution of methamidofos, malathion, and methiocarb in different crops grown in greenhouses has been studied, including the presence of metabolites such as malaoxon, methiocarb sulfoxide, and methiocarb sulfone. The analytical method is based on dichloromethane extraction and GC-PFPD analysis. It has been validated establishing performance parameters such as recovery rates, precision, linear ranges, and limits of detection and quantification, which are low enough for ensuring that their corresponding MLRs can be adequately quantified. Samples of treated cucumbers and peppers grown in greenhouses were collected and analyzed during a 15-day period for obtaining the diminution rates of methamidofos and malathion. The behavior of methiocarb in treated green beans and tomatoes has been studied using analysis of variance (ANOVA) as the statistical tool, for establishing the influence of crop, season, application dose, and greenhouse design.

SE—Structures and Environment: Natural Ventilation and Microclimatic Performance of a Large-scale Banana Greenhouse

Natural ventilation performance is one of the key parameters for climate control in large scale, Canarian type of greenhouses which are rapidly expanding along the Atlantic coast in Morocco. The climatic conditions were measured and analysed in a 1ha Canarian type of greenhouse, with a mature banana crop which was the second most widespread crop under protected cultivation in the region of Rabat, Morocco. A global energy balance of the greenhouse is deduced, allowing for the determination of ventilation flux. New ventilation functions for very large-scale greenhouses are presented and compared with other existing functions.The greenhouse ventilation performances are compared with those of other greenhouse types and discussed with respect to the improvement of greenhouse design, the use of insect-proof nets and irrigation control.

SE—Structures and Environment: Improvement of Greenhouse Insulation with Restricted Transmission Loss through Zigzag Covering Material

The design of modern greenhouses is based on a compromise between a maximized transmission of solar radiation and a minimized heat loss within an economic context. This could be satisfied by the use of transparent double-layered zigzag plates as a covering material. The MatLight computer model was developed to compute the effect on transmission of a greenhouse cover due to the use of these plates. A greenhouse cover without construction elements such as gutters and glazing bars, with a span width of 3·2 m and a roof slope of 25°, was covered with a double zigzag plate. This greenhouse was proved to have a diffuse transmission loss of 1·6% and a gain in transmitted direct radiation up to 5% in winter for NS-orientation, compared with a single-glass cover. The insulation of the cover increases by 16%. This is a promising result for practical application.

Visualization of Greenhouse Environment by VRML

In this study, we developed a greenhouse visualization system by using VRML (Virtual Reality Modeling Language) that is a high performance language for 3-D visualization on WWW (World Wide Web). We developed a converter from designed parameters of a greenhouse to VRML format. Plant grown in a greenhouse can be chosen as one of parameters. Plant was visualized with 2 textured planes. We also made a database of two-dimensional plant images of several growth stages from 3-D plant shape generated by AMAP (a plant modeling system that produces very precise 3-D plant shape). With the developed system, greenhouses were visualized for the validation of the system. By using the system, walk thorough simulation in the greenhouses was possible in spite of the huge number of plant and building data. In conclusion, the system developed in this study can produce a very high quality images and will be used for design and visualization of greenhouses with very low cost.