Pietro Picuno

Analysis of the efficiency of greenhouse ventilation using computational fluid dynamics

A systematic analysis of the ventilation process in greenhouses was performed with the use of computational fluid dynamics (CFD). First, the validity of the model assumptions was established by comparing the numerical results with experimental data. A good agreement between the numerical data and the experimental measurements was found if a two-scale k-e turbulence model is applied in the CFD simulation. Then, the influence of design characteristics, such as the greenhouse length, on the ventilation was examined in the case of a typical Mediterranean-type greenhouse. It was demonstrated that CFD is a powerful tool for developing improved designs with respect to ventilation efficiency but the results cannot be generalized. Therefore, a systematic investigation of the most common greenhouse types is necessary.

Computational analysis of ventilation in greenhouses at zero- and low-wind speeds.

Abstract A systematic analysis of the natural ventilation process in greenhouses at no-wind and low-wind-speed conditions was performed with the use of Computational Fluid Dynamics (CFD). The validity of this approach was first checked with success by comparing the numerical results with experimental data obtained from the literature. Numerical predictions of the ventilation efficiency of typical Mediterranean-type greenhouses were obtained for various ventilator configurations. These computer simulations were based on a realistic representation of the heat sources and the boundary conditions related to the problem. The contribution of specific ventilators to the greenhouse air renewal was analysed. The importance of side-wall ventilators for an efficient thermally driven ventilation (‘buoyancy effect’) was confirmed. It was demonstrated that CFD is a powerful tool for developing improved designs with respect to ventilation efficiency.

Review, mapping and analysis of the agricultural plastic waste generation and consolidation in Europe.

A review of agricultural plastic waste generation and consolidation in Europe is presented. A detailed geographical mapping of the agricultural plastic use and waste generation in Europe was conducted focusing on areas of high concentration of agricultural plastics. Quantitative data and analysis of the agricultural plastic waste generation by category, geographical distribution and compositional range, and physical characteristics of the agricultural plastic waste per use and the temporal distribution of the waste generation are presented. Data were collected and cross-checked from a variety of sources, including European, national and regional services and organizations, local agronomists, retailers and farmers, importers and converters. Missing data were estimated indirectly based on the recorded cultivated areas and the characteristics of the agricultural plastics commonly used in the particular regions. The temporal distribution, the composition and physical characteristics of the agricultural plastic waste streams were mapped by category and by application. This study represents the first systematic effort to map and analyse agricultural plastic waste generation and consolidation in Europe.

Innovative Material and Improved Technical Design for a Sustainable Exploitation of Agricultural Plastic Film

The use of plastic material in agriculture has been growing during the last decades thanks to the benefits it provides in agricultural production. The durability of plastic films is related to the meteorological and environmental conditions, as well as to the consequence of stress they are subjected to during their operational life. An improvement in the technical design of the agricultural plastic film is connected with a closer link between its chemical formulation and the engineering performance. The present article presents a general review about innovative material and new techniques for mechanical recycling of agricultural plastic film.

The effect of sand wind, temperature and exposure time on tri-layer polyethylene film used as greenhouse roof

This work aims at studying the degradable effect of artificial ageing on tri-layer stabilised low-density polyethylene (PE) films used as greenhouse cover in the North Africa environment. The film was supplied by Agrofilm company, Algeria. Colour additives and infra-red and ultraviolet stabilisers were used. Optical, thermal, surface and mechanical properties have been investigated for virgin sample and samples exposed to sand wind for different exposure periods (1, 2, 4 and 8 h) of artificial ageing at a temperature of 40°C simulating Saharan environment. The findings of this study show that the harsh environmental conditions of exposure to temperature and sand wind have significant degradable effects on the properties of the PE film. The transmission of the film and its mechanical properties have reduced significantly due to exposure to sand wind and temperature. The study revealed also that the degradation parameters measured are directly related to the criteria for evaluating the effectiveness of agricultural greenhouse.

New Technologies for Ecosystem Analysis Planning and Management

Planning the rural environment is one of the most intriguing examples of technical challenge where a multi-disciplinary approach plays a crucial role. The agricultural production, both food and non-food, the social role of rural settlements, the state and diffusion of the infrastructural networks, the rural architectonic heritage that in many countries constitutes a major positive value, should be appropriately considered and sinergically interlaced for a sound planning of agricultural biosystems.

Multilayers Polyethylene Film for Crop Protection in Harsh Climatic Conditions

In this work the performance and durability of a new generation of greenhouse covers, in which the cover is composed of five layers, are investigated. A sand wind ageing was performed under different exposure conditions. Surface morphology and chemical, physical, and thermal characteristics were investigated by using optical microscopy, FTIR, and tensile test techniques. In addition, the mechanical integrity of the five-layer film was assessed. The analysis indicated that the sand wind treatments have a significant influence only on the performance of the film. An attempt has been done to compare the properties of the five-layer film with the monolayer and trilayer films with or without air bubble under similar conditions. The results revealed that the five-layer film proved to be a promising greenhouse covering film.

Technical properties of regenerated plastic material bars produced from recycled Agricultural Plastic Film

The increased use of plastic material in many different agricultural applications causes high volumes of waste. The mechanical recycling of postconsumption plastic is a suitable system for the recovery of these materials. With the aim of evaluating the mechanical and physical characteristics of plastic bars’ profiles, obtained by recycling different polymeric mixtures of agricultural plastic film. Experimental tests were performed on different blends of heterogeneous material. Bars, made from recycled agricultural plastic film were produced through mechanical recycling, mixed with calcium carbonate, high density polyethylene, ‘densified’ polyethylene from scrap material, wood powder, and glass fibers. GRAPHICAL ABSTRACT

Computational Study of the Natural Ventilation Driven by Buoyancy Forces

Abstract The ventilation behaviour of greenhouse structures when the wind speed is low and the “buoyancy effect” is the main driving force of the indoor air flow has been analysed with the use of Computational Fluid Dynamics. These numerical (CFD) simulations offer a detailed picture of the temperature spatial distribution and the air velocity field. These data can be used for analysing the contribution of every ventilator to the general ventilating performance of the greenhouse. As an example, the great importance of both roof and side ventilators for an efficient thermally driven ventilation was numerically demonstrated.

Valorization of Agricultural By-Products Within the “Energyscapes”: Renewable Energy as Driving Force in Modeling Rural Landscape

Due to several growing environmental constraints, renewable energy sources currently play an increasingly crucial role that, owing to their high temporal and spatial variability, needs a careful planning approach. It is important therefore to develop a framework that examines the distribution of different energy sources in a spatio-temporal context. From an energy point of view, a regional territory, such as an internal southern Italian region (the Basilicata Region), can be considered as a paradigmatic case study, because it is characterized by significant sources of renewable energy (e.g., biomass, wind, solar, hydro) connected to its morphological and environmental structure, as well as to its agricultural and food productions. The present paper in based on an analysis of the spatial supply and relationships between renewable energy potentials and rural land, through the use of a Geographic Information System that has been implemented with the aim to analyze the energy system, as well as to optimize the valorization of biomass resources that may be still unutilized within the bioenergy production chain. This study has been carried out even to bridge the gap between energy systems modeling and landscape planning. Within this context, an “Energyscape” may be considered as the effect resulting on the rural landscape from a combination of the supply, demand and infrastructure for energy. This framework could be therefore a starting point for an interdisciplinary analysis able to figure out optimal solutions in decision-making processes, which duly respect the protection and restoring of endangered ecosystems, supporting the decision about an optimal spatial localization of energy plants as well.