Evaluation of the radiometric properties of roofing materials for livestock buildings and their effect on the surface temperature

Passive systems, such as high solar reflective roofing materials, protective facades, vegetative green walls and roofs, can be used in order to control solar heat gain in buildings. These sustainable technologies can reduce the temperature of the external surface of the building envelope, so reducing the energy consumption for cooling in summer. The radiometric properties of metallic roofing materials and their effects on the surface temperature were evaluated. Nine smooth metallic materials used for livestock buildings were tested; 4 were made of aluminium and the other 5 of steel and they were characterised by different colours. Solar reflectivity and long wave infrared emissivity were evaluated by means of laboratory tests; the influence of the radiometric properties on the surface temperature was evaluated in the field by using an experimental structure in Summer. The solar reflectivity coefficient ranged from 7.1% for the brown aluminium to 40.1% for the red steel; significant differences of the temperatures were recorded when the solar radiation hitting the metallic surface was higher than 600 W m-2. A difference of 13.4% of the solar reflectivity coefficient resulted in a difference of the surface temperature of up to 8 °C. Variation of the slope from 15° to 40° resulted in an increase of the surface temperature of more than 8 °C. The value of the convection coefficient was calculated by means of the data measured in the field, and the mean value was equal to 12.2 W m-2 K-1

Correlation between agrochemicals, solar radiation and mechanical properties of greenhouse plastic films

A research was carried out in order to evaluate how agrochemicals contamination and solar radiation influence the mechanical properties of ethylene-vinyl acetate copolymer (EVA) films. The films, manufactured adding several different combinations of light stabilizers, were subjected to natural and artificial weathering and to three agrochemicals commonly used during the cultivation practices. Two sets of field trials were carried out from 2006 to 2007 at the experimental centre of the University of Bari (Italy). The films, installed on steel arches of low tunnels, were periodically sprayed with the agrochemicals containing iron, chlorine and sulphur. For control the same films, mounted over other low tunnels, were not sprayed. Stress and strain at break of the film samples, taken at fixed time intervals in the field and after exposure in an artificial ageing chamber, were measured. Tests were conducted to evaluate the chemical contaminants absorbed by the films. Solar radiation falling on the films under test was continuously measured and recorded by means of a pyranometer and a CR10x Campbell data logger. The results of the tests showed that the different light stabilizers influenced the behaviour of the films in presence of the sprayed agrochemicals. The experimental data were investigated evaluating the cumulative solar radiation, the kind of anti-UV additive and the absorbed contaminants. Concerning the agrochemicals which were absorbed by the films, values up to 6800 ppm of sulphur were recorded during the tests. The research allowed the identification of the suitable additives in relation with used agrochemicals. The tests showed that an improved resistance to the agrochemicals was recorded for the EVA film stabilized with NOR-HALS plus UV filter

Effects of agrochemicals, ultra violet stabilisers and solar radiation on the radiometric properties of greenhouse films

Agrochemicals, based on iron, sulphur and chlorine, generate by products that lead to a degradation of greenhouse films together with a decrease in their mechanical and physical properties. The degradation due to agrochemicals depends on their active principles, method and frequency of application, and greenhouse ventilation. The aim of the research was to evaluate how agrochemical contamination and solar radiation influence the radiometric properties of ethylene-vinyl acetate copolymer greenhouse films by means of laboratory and field tests. The films, manufactured on purpose with the addition of different light stabiliser systems, were exposed to natural outdoor weathering at the experimental farm of the University of Bari (Italy; 41° 05' N) in the period from 2006 to 2008. Each film was tested for two low tunnels: one low tunnel was sprayed from inside with the agrochemicals containing iron, chlorine and sulphur while the other one was not sprayed and served as control. Radiometric laboratory tests were carried out on the new films and on samples taken at the end of the trials. The experimental tests showed that both the natural weathering together with the agrochemicals did not modify significantly the radiometric properties of the films in the solar and in the photosynthetically active radiation wavelength range. Within six months of experimental field tests the variations in these radiometric characteristics were at most 10%. Significant variations, up to 70% of the initial value, were recorded for the stabilised films in the long-wave infrared radiation wavelength range

Thermal Behaviour Of Green Façades in Winter Climatic Conditions

Green infrastructures inside cities represent an effective strategy to face with the increasingly urgent environmental problems. Green systems applied to building envelope are among the most applicable and useful solutions. These provide many significant advantages at different scales. Green façades (GF) are a typology of vertical green systems, applied to the vertical components of the building envelope. GF allow to save energy for air conditioning, by improving the envelope thermal performances. Energy behaviour of GF has been more deeply studied in warm periods, than in cold ones. This paper aims to analyse wintertime energy performances of GF. Evaluations were carried out based on the experimental data collected on two GF, in Bari (Italy), under Mediterranean climatic conditions. The experimental set-up included also a bare wall (BW), used as control. The heating effect provided by the greenery was pointed out through statistical and energy analyses. At night-time, the covered walls (CW) were warmer than the bare one up to 3.5°C. The dependence of night-time heating effect on microclimate parameters, as external air temperature, relative humidity and wind speed, was studied. External air temperature was found to be the most influencing factor: as it dropped, the heating effect increased. Overall energy transfer through the CW was lower than through the BW at night-time. The long-wave infrared energy radiative losses were reduced thanks to the green layer, which acted as a thermal barrier. These findings proved that GF improve winter night-time thermal performance by reducing energy losses

Hydrolyzed protein based materials for biodegradable spray mulching coatings

Low density polyethylene (LDPE) films are widespread used in agriculture for soil mulching. The use of LDPE mulching films causes the serious drawback of huge quantities of waste to be disposed of. Over the last years the growing environmental awareness has been prompting the research to develop a new generation of mulching products starting with raw materials from renewable origin. These materials have to retain their physical and mechanical properties while in use and have to be compostable or biodegradable at the end of their life, degrading via micro-organisms into carbon dioxide or methane, water and biomass. The research is focused on the development of novel biodegradable polymeric materials based on hydrolyzed proteins, derived from waste products of the leather industry. Biodegradable soil mulching coatings were realized with these biodegradable polymeric materials by means of spray techniques; the coatings were tested in a Ligustrum ovalifolium cultivation carried out inside a greenhouse. This paper describes the functionalities of the new bio-based mulching coatings, which were developed and tested in real scale greenhouse cultivation tests. During the trial, the biodegradable soil mulching materials showed suitable properties for an efficient and profitable use in agriculture. The innovative biodegradable spray coatings lasted up to 18 months. The biodegradable materials could be the environmentally friendly alternatives to synthetic petro-chemical polymers and could contribute to a sustainable agriculture

WINTERTIME THERMAL PERFORMANCE OF GREEN FAÇADES IN A MEDITERRANEAN CLIMATE

The increasing environmental issues have afforded opportunities for a widespread application of green systems in urban areas. Greening the building with green roofs and vertical green systems can be a design and retrofitting strategy to improve building energy performance in summer and in winter. Research efforts have been mainly concentrated on their energy saving function during warm periods. Green façades have a great application potential thanks to the space available in urban environment. The effect of green façades on building energy performance has been studied mainly for warm periods. In order to evaluate the effect during cold periods, an experiment was conducted in Bari, Italy, for two years. Pandorea jasminoides variegated and Rhyncospermum jasminoides were tested as evergreen climbing plants on walls; a third wall was used as control. The night-time temperature of the covered wall was higher than the uncovered wall temperature by up to 3.5°C, thanks to the presence of plants. The thermal barrier function performed by the vegetation layer was analysed. The influence of outdoor air temperature, relative humidity and wind velocity on the façades thermal effect during night-time was investigated. The experimental test demonstrated that both Pandorea jasminoides variegated and Rhyncospermum jasminoides are suitable for green façades in the Mediterranean climatic area during winter. The use of the green façades allowed increasing the thermal performance of the walls during night-time. They also reduced the surface temperature changes throughout the day

Implementing a GIS-Based Digital Atlas of Agricultural Plastics to Reduce Their Environmental Footprint; Part I: A Deductive Approach

The agricultural sector has benefitted over the last century from several factors that have led to an exponential increase in its productive efficiency. The increasing use of new materials, such as plastics, has been one of the most important factors, as they have allowed for increased production in a simpler and more economical way. Various polymer types are used in different phases of the agricultural production cycle, but when their use is incorrectly managed, it can lead to different environmental impacts. In this study, an applied and simplified methodology to manage agricultural plastics monitoring and planning is proposed. The techniques used are based on quantification through the use of different datasets (orthophotos and satellite images) of the areas covered by plastics used for crop protection. The study area chosen is a part of the Ionian Coast of Southern Italy, which includes the most important municipalities of the Basilicata Region for fruit and vegetable production. The use of geographical techniques and observation methodologies, developed in an open‐source GIS environment, enabled accurate location of about 2000 hectares of agricultural land covered by plastics, as well as identification of the areas most susceptible to the accumulation of plastic waste. The techniques and the model implemented, due to its simplicity of use and reliability, can be applied by different local authorities in order to realize an Atlas of agricultural plastics, which would be applied for continuous monitoring, thereby enabling the upscaling of future social and ecological impact assessments, identification of new policy impacts, market searches, etc

Effect of Leaf Area Index on Green Facade Thermal Performance in Buildings

Green facades applied on a building's envelope allow achieving the building's passive thermal control and energy consumption reduction. These are complex systems and many site- and plant-specific parameters influence their energy behavior. The leaf area index (LAI) is a relevant plant characteristic to consider. Solar shading and latent heat loss of plant evapotranspiration are the two main cooling mechanisms. The aim of this study was to assess the cooling effect provided by an evergreen south oriented green facade in summer in a Mediterranean area and to investigate what happens when LAI changes. Experimental data were used to calculate the cooling effect provided by the facade. Simulations with different LAI values were performed to determine the related cooling effect. The canopy solar transmissivity decreased by 54% for every LAI unit increase. LAI significantly influenced the green facade cooling performance. As LAI increased, solar shading and latent heat increased; this was relevant until an upper limit value of 6. An exponential equation to calculate the mean extinction coefficient (k(m)), and a polynomial relationship, with very good agreement, were proposed to calculate shading and latent heat as function of LAI. The findings of this research can effectively contribute to fill still existing gaps on green facades' energy performance and to the energy simulation of buildings equipped with them

Evaluation of coloured nets in peach protected cultivation

The aim of this paper is to investigate the influence of the radiometric properties of coloured nets on peach tree photomorphogenesis. The modification of the spectral distribution of the transmitted radiation and thus the effects on the tree vegetative and productive activity were studied. A field experimental test using coloured nets for the protection of peach trees was carried out during 2008 at the experimental farm of the University of Bari, latitude 41° 05' N. A blue net and a red net, characterised by a nominal shading factor of 40%, and a neutral net with a nominal 12% shading factor were tested. Peach trees in open field conditions were used as control. The effects of the nets on the trees growth were correlated with the radiometric properties of the nets, which were evaluated by means of laboratory tests. The red and blue nets influenced mainly the B/FR ratio: the former net decreased and the latter increased the B/FR ratio. The nets influenced the quantity as the quality of the yield. The red net increased the shoot growth of the trees more than the blue one. The nets influenced positively the fruit weight and skin colour in comparison to the open-field

Mapping Greenhouse Plastic Wastes in the West Region of Portugal

Plastic materials are used in many applications in agriculture, as greenhouse and tunnel covering films, direct coverings, shading and protective nets, irrigation pipes, fertilizers bags, pots and others. In Mediterranean countries, plastic film is the most common greenhouse covering material. Due to the direct exposure to solar radiation and wind, greenhouse plastic cover needs to be replaced every 6 to 45 months, depending on the material. The huge quantities of plastic waste produced need a proper management in order to avoid environmental and economic impacts. The plastic waste is usually recycled by special companies that collect and treat this waste material. The aim of this study was to apply Geographical Information Systems and photointerpretation techniques to evaluate the amount of plastic waste produced in one of the most important regions of greenhouse production in Portugal, the West Region specifically the Torres Vedras municipality. The methodology has integrated the characterization of the type of plastic covering material and the cartography of the greenhouses land units. It was used the Land Use Map 2007, Bing Map images and administrative boundaries to determine the geographic position and the types of greenhouses. For each administrative unit it was calculated the frequency and total greenhouses area. The identification of the type of plastic material was made by photointerpretation and direct interviews in one Company that sells material for greenhouses in Torres Vedras. The database created allowed to determine the amount of plastic used as greenhouse cover materials and to identify the needs for recycling in this area. The geodatabase produced is a first step to monitoring plastic waste production in time and space