Search

Urban agriculture (UA) initiatives have been increasing in recent years as a nature-based solution for achieving many of the 2030 UN Sustainable Development Goals. However, climate change is expected to have effects on rainfall patterns, which are likely to impact urban food production. The main aim of this paper is to evaluate how issues related to water sources for UA have been addressed in the scientific literature from two different socioeconomic and environmental realities, Brazil and Italy. The method involved a systematic literature review, considering the PRISMA guidelines. The Web of Science database and papers' reference lists were used for retrieving original articles, published in 2000–2020 interval, indexed on scientific databases, and containing data on the typology and quality of water sources used in UA studies. After applying the eligibility criteria, 191 papers were selected – Brazil (108) and Italy (83). The last five years have seen an intensification of studies into issues involving water. Tap water has been identified as an important source of irrigation water for UA, if not the main one. No studies were found that addressed the impact of UA on public water supply systems. The findings point towards more sustainable practices involving the reuse of water and adaptive practices towards water security. We identified that innovative production systems like container farming, aquaponics and indoor agriculture, as well as cultivation of fruit trees, wild edible plants and varieties with low water requirements can represent water-saving options.

This study deals with tensile tests on rigid polymeric innovative material for greenhouse covering. Specimens of polycarbonate Makrolon® UV Climate Control blue were analyzed. Tension tests were conducted on bone-shaped samples, according to European standards, and at different temperatures from 20 °C to 80 °C on the basis of the summer temperatures registered by the greenhouses supporting metal structures in contact with the plastic covering. During tensile test the surface temperature of the specimens was measured using infrared technology. Finally, the obtained strain and temperature trend are discussed and an interpretation of the mechanical behaviour of the material is given based on a Griffith like approach.

The Journal of Agricultural Engineering (JAE) celebrates with this issue the publication of its fiftieth volume. The Journal was founded in 1969, on the initiative of the Italian Society of Agricultural Engineering (AIIA) to publish the results of scientific and experimental acquisitions of the sector, noted the serious lack of adequate editorial venues for what was then called Genie Rural. Initially published in Italian under the name of Rivista di Ingegneria Agraria by the publisher Edagricole, it was one of the first sector journals in Europe and since 1970 it has always followed an annual periodicity, with each volume consisting of four issues printed quarterly, for a total of almost 1200 scientific papers published so far.

The current intensification of the use of plastic materials in agriculture, although has increased significantly the productivity, is also generating growing adverse effects on the environment of the agro-ecosystem. The agriculture is responsible for a massive use of plastic materials, in addition to energy and water inputs, chemical fertilizer and pesticides. Besides the pollution generated during the manufacture, at the end of their lifetime plastic materials used for crop covering, soil mulching, packaging, containers, pots, irrigation and drainage pipes, may became a pollution source when improperly disposed, leaved on the ground or burned. Instead the agricultural plastic waste (APW), if correctly collected, can be used as a new secondary raw material or as an energy source. An adequate APW management can prevent economical losses and environmental damages. The territory of the Barletta, Andria, Trani Province (BAT), in the Apulia Region, South Italy, is an agricultural area characterized by vineyards, olive groves, orchards and vegetables; it represents an area of intense production of plastic wastes and with a widespread problem linked to the application of unacceptable disposal practices. The goal of this study is to define and quantify the different types of plastic waste produced by the agricultural practice in a restricted area of the municipal area of Trani and Barletta, to localize the points where the most remarkable quantities of them are generated, and to provide the local Authorities and the decision makers of a useful tool for implementing an efficient and effective waste management. A dedicated geo-referenced database was designed using land use maps in a GIS environment and applying a methodology that can be functional for any kind of agricultural plastic waste. The resulting database gives updated and complete information on the plastic waste generation, over the land, related to the cultivation kind.

Building greenery systems can represent a sustainable solution for new buildings design and for existing buildings retrofitting, in order to improve the thermal energy performance of buildings, to decrease building energy loads and to contrast the Urban Heat Island. Green façades can influence thermal properties of a building by means of different important mechanisms: the shading, the cooling, the insulating and the wind barrier effect. Moreover, green façades accomplish heating effect in the cold season and at nighttime. An experimental test was developed at small scale at the University of Bari (Italy) from 2014 to 2016 for testing two different green façades. The plant species chosen were Pandorea jasminoides variegated and Rhyncospermum jasminoides, two evergreen climbing plants. A third uncovered wall was used as control. The thermal behaviour of the plants was analysed during the 2016 summer season, by keeping in consideration the external surface temperature of the building and the temperature of the airgap behind the green vertical systems. The daylight temperatures observed on the plant-covered walls during representative days were lower than the respective temperatures of the uncovered wall up to 7.0°C. During nighttime, the temperatures behind the plants were higher than the respective temperatures of the control wall up to 2.2°C. The results shown in the present research allow delineating the behaviour of the two plant species during summer in the Mediterranean climate region.

Green walls can be used to control the building microclimate as passive systems for energy saving. Three vertical walls were built at the University of Bari (Italy). The first wall was covered with Pandorea jasminoides variegated and the second with Rhyncospermum jasminoides; the third wall was kept uncovered as a control. High-definition infrared images were recorded, and several climatic parameters concerning the walls and the ambient conditions were collected during the experimental test. The daylight temperatures observed on the shielded walls during warm days were lower than the respective temperatures of the uncovered wall by up to 9·0°C; the nighttime temperatures observed during cold days were higher than the respective temperatures of the control wall by up to 6·0°C. The effective thermal resistance of the plants was calculated, using experimental data for a whole year; it ranged from 0·07 to 3·61 m2 K/W.

The intrinsic factor of variability of renewable energy sources often limits their broader use. The photovoltaic solar systems can be provided with a power back up based on a combination of an electrolyser and a fuel cell stack. The integration of solar hydrogen power systems with greenhouse heating equipment can provide a possible option for powering stand-alone greenhouses. The aim of the research under development at the experimental farm of Department of Agro-Environmental Sciences of the University of Bari Aldo Moro is to investigate on the suitable solutions of a power system based on photovoltaic energy and on the use of hydrogen as energy vector, integrated with a ground source heat pump for greenhouse heating in a self sustained way. The excess energy produced by a purpose-built array of solar photovoltaic modules supplies an alkaline electrolyser; the produced hydrogen gas is stored in pressured storage tank. When the solar radiation level is insufficient to meet the heat pump power demand, the fuel cell starts converting the chemical energy stored by the hydrogen fuel into electricity. This paper reports on the description of the realised system. Furthermore the efficiency and the operational mode of the electrolyser were evaluated during a trial period characterised by mutable solar radiant energy. Anyway the electrolyser worked continuously in a transient state producing fluctuations of the hydrogen production and without ever reaching the steady-state conditions. The Faradic efficiency, evaluated by means of an empirical mathematic model, highlights that the suitable working range of the electrolyser was 1.5÷2.5 kW and then for hydrogen production more than 0.21 Nm3h–1.

An innovative wireless monitoring system for measuring greenhouse climatic parameters was developed to overcome the problems related to wires cabling such as presence of a dense net of wires hampering the cultivation practices, wires subjected to high temperature and relative humidity, rodents that can damage wires. The system exploits battery-powered environmental sensors, such as air temperature and relative humidity sensors, wind speed and direction, and solar radiation sensors, integrated in the contest of an 802.15.4-based wireless sensors network. Besides, a fruit diameter measurement sensor was integrated into the system. This approach guarantees flexibility, ease of deployment and low power consumption. Data collected from the greenhouse are then sent to a remote server via a general packet radio service link. The proposed solution has been implemented in a real environment. The test of the communication system showed that 0.3% of the sent data packed were lost; the climatic parameters measured with the wireless system were compared with data collected by the wired system showing a mean value of the absolute difference equal to 0.6°C for the value of the greenhouse air temperature. The wireless climate monitoring system showed a good reliability, while the sensor node batteries showed a lifetime of 530 days.

This monograph is a critical review of the biological activities that occur during virgin olive oil (VOO) extraction process. Strategic choices of plant engineering systems and of processing technologies should be made to condition the enzymatic activities, in order to modulate the nutritional and the sensory quality of the product toward the consumer expectations. “Modulation” of the product quality properties has the main aim to predetermine the quantity and the quality of 2 classes of substances: polyphenols and volatile compounds responsible of VOO nutritional and sensory characteristics. In the 1st section, a systematic analysis of the literature has been carried out to investigate the main olive enzymatic activities involved in the complex biotransformation that occurs during the mechanical extraction process. In the 2nd section, a critical and interpretative discussion of the influence of each step of the extraction process on the polyphenols and the volatile compounds has been performed. The effect of the different mechanical devices that are part of the extraction process is analyzed and recommendations, strategies, and possible avenues for future researches are suggested. Practical Application In the field of virgin olive oil industry, time and energy should be spent on developing innovative processing plants and equipment able to better modulate the physical parameters that influence endogenous olive enzyme activities, such as temperature, time, amounts of processing water and oxygen. This review paper can be a useful resource to design and develop innovative equipment by offering an exhaustive analysis of mechanical effects of industrial devices and biological effects of endogenous enzymes on the sensory and nutritional properties of virgin olive oil.

This paper presents a technoeconomic analysis of a solar combined heat and power (S-CHP) system based on hybrid photovoltaic-thermal (PVT) collectors for distributed cogeneration in a greenhouse tomato-farm in Bari, Italy. The thermal and electrical demands of the greenhouse of interest are currently fulfilled by a gas-fired CHP system that features an internal combustion engine (ICE) prime mover, and partially by an auxiliary gas boiler and electricity from the grid. A PVT-water S-CHP system is designed and sized based on a transient model, with hourly weather data and measured demand data given as inputs. Annual simulations are performed to predict the transient behaviour of the S-CHP system and to assess the system’s energy outputs. The economic profitability of such solution is also evaluated by considering the investment costs and cost savings due to the reduced on-site energy consumption. The results show that, with an installation area of 30,000 m2, the PVT S-CHP system is able to cover up to 73% of the annual thermal demand of the greenhouse, while delivering a net electrical output 2.6 times that of the annual electrical demand. This performance is similar to that achieved by the equivalent ICE-CHP system (92% and 2 times, respectively). Furthermore, the total annual cost saving of the PVT S-CHP system is more than 6 times higher than that of the ICE system, due to the much lower fuel cost of the PVT system. Similarly, the potential CO2 emission reduction associated with the PVT system is considerably higher, at 3010 tCO2/year saved (vs. 86 tCO2/year). The payback time of the PVT system is not significantly longer than that of the ICE system (10.4 years vs. 8.4 years), but its levelized cost of energy is much lower (0.076 €/kWh vs. 0.132 €/kWh) due to the higher annual cost savings. These results indicate that such PVT S-CHP systems have an excellent technoeconomic potential in the proposed greenhouse applications and could be competitive over conventional fossil-fuel-based ICE-CHP systems in terms of energetic, economic and also environmental metrics.

The effectiveness of experimental nets in preventing the access of adult meadow spittlebug Philaenus spumarius L., the main vector of Xylella fastidiosa Wells et al. subspecies pauca, sequence type (ST) 53, in olive tree nurseries and orchards was evaluated. To optimize the net design, mesh size, kind of fabric, thread typology, and radiometric properties, six nets with different mesh sizes and kinds of fabric were evaluated in laboratory and in field experiments. Laboratory bioassays evaluating the capability of adult spittlebugs to pass through nets with different mesh sizes (1.2, 1.8, 2.4 mm) showed that all nets with a mesh size equal to or lower than 2.4 mm prevented insect crossing. These results were confirmed in field conditions using an experimental net box apparatus. Further laboratory tests showed a positive correlation between porosity and radiometric properties of the nets. Three prototypes of thermally stabilized flat woven nets made of circular cross-sectional yarns, knitted net with strips, and knitted nets made of yarns were tested after the evaluation of their potential usability in terms of porosity stability. The knitted net features were found to be the most suitable. The net transmissivity of the total and direct component of solar radiation in the photosynthetically active radiation and the infrared ranges increased with the net porosity. A prism-shaped wooden frame with a triangular base covered with the knitted net with a 2.4 mm mesh confirmed the insect’s capability of reaching considerable heights, up to 2.85 m. Hence, based on our results, the monowire knitted net with a 2.4 mm mesh can be used in open field nursery and olive orchards to prevent the access of P. spumarius adults and to shield the openings of greenhouse nurseries.

A greenhouse containing an integrated system of photovoltaic panels, a water electrolyzer, fuel cells and a geothermal heat pump was set up to investigate suitable solutions for a power system based on solar energy and hydrogen, feeding a self-sufficient, geothermal-heated greenhouse. The electricity produced by the photovoltaic source supplies the electrolyzer; the manufactured hydrogen gas is held in a pressure tank. In these systems, the electrolyzer is a crucial component; the technical challenge is to make it work regularly despite the irregularity of the solar source. The focus of this paper is to study the performance and the real energy efficiency of the electrolyzer, analyzing its operational data collected under different operating conditions affected by the changeable solar radiant energy characterizing the site where the experimental plant was located. The analysis of the measured values allowed evaluation of its suitability for the agricultural requirements such as greenhouse heating. On the strength of the obtained result, a new layout of the battery bank has been designed and exemplified to improve the performance of the electrolyzer. The evaluations resulting from this case study may have a genuine value, therefore assisting in further studies to better understand these devices and their associated technologies.

This paper focuses on the thermo-economic analysis of a hybrid solar-biomass CHP combined cycle composed by a 1.3-MW externally fired gas-turbine (EFGT) and a bottoming organic Rankine cycle (ORC) plant. The primary thermal energy input is provided by a hybrid concentrating solar power (CSP) collector-array coupled to a biomass boiler. The CSP collector-array is based on parabolic-trough concentrators (PTCs) with molten salts as the heat transfer fluid (HTF) upstream of a fluidized-bed furnace for direct biomass combustion. Thermal-energy storage (TES) with two molten-salt tanks (one cold and one hot) is considered, as a means to reducing the variations in the plant's operating conditions and increasing the plant's capacity factor. On the basis of the results of the thermodynamic simulations, upfront and operational costs assessments, and considering an Italian energy policy scenario, the global energy conversion efficiency and investment profitability are estimated for 2 different sizes of CSP arrays and biomass furnaces. The results indicate the low economic profitability of CSP in comparison to only biomass CHP, because of the high investment costs, which are not compensated by higher electricity sales revenues. © 2017 The Authors.

Fifteen HDPE agricultural nets were tested inside a micro wind tunnel (0.1345 m diameter) to establish their characteristic air flow rate vs pressure drop curves with velocities >4 m s −1 . The air pressure drop through the net was accounted for, with reference to the Bernoulli scheme, by means of the loss coefficient. Experimental results confirmed those available in the literature, in terms of the dependence of the pressure drop on the velocity squared and the net porosity, e , by means of the function h ( e ) = ( 1 − e 2 / e 2 ) . The influence of the orifice geometry was investigated and an effect equivalent to the increase in net porosity was identified in textile pores with elongated shapes. As with previous studies, the loss coefficient trend was found to fit the product of two functions, one depending on the porosity, and the other on the Reynolds number defined using the pore equivalent diameter. The calculated values of the loss coefficient show deviations from experimental results in the range of 19.9–41.1%. In addition, a new formulation for the loss coefficient, dependent only on the porosity and wet perimeter was proposed. Except for higher porosity nets the simplified formulation, showed the best match with the experimental data. The two formulations of the loss coefficient proposed here were compared with those found in the literature.

Greenhouses play a significant function in the modern agriculture economy even if require great amount of energy for heating systems. An interesting solution to alleviate the energy costs and environmental problems may be represented by the use of geothermal energy. The aim of this paper, based on measured experimental data, such as the inside greenhouse temperature and the heat pump performance (input and output temperatures of the working fluid, electric consumption), was the evaluation of the suitability of low enthalpy geothermal heat sources for agricultural needs such as greenhouses heating. The study was carried out at the experimental farm of the University of Bari, where a greenhouse was arranged with a heating system connected to a ground-source heat pump (GSHP), which had to cover the thermal energy request. The experimental results of this survey highlight the capability of the geothermal heat source to ensue thermal conditions suitable for cultivation in greenhouses even if the compressor inside the heat pump have operated continuously in a fluctuating state without ever reaching the steady condition. Probably, to increase the performance of the heat pump and then its coefficient of performance within GSHP systems for heating greenhouses, it is important to analyse and maximise the power conductivity of the greenhouse heating system, before to design an expensive borehole ground exchanger. Nevertheless, according to the experimental data obtained, the GSHP systems are effective, efficient and environmental friendly and may be useful to supply the heating energy demand of greenhouses.

A pilot power system formed by photovoltaic panels, alkaline electrolyser and fuel cell stacks was designed and set up to supply the heating system of an experimental greenhouse. The aim of this paper is to analyse the main safety aspects of this power system connected to the management of the pressured hydrogen, such as the explosion limits of the mixture hydrogen-oxygen, the extension of the danger zone, the protection pressure vessels and the system to make unreactive the plant. The electrolyser unit is the core of this plant and from the safety point of view has been equipped with devices able to highlight the malfunctions before they cause damages. Alarm situations are highlighted and the production process is cut off in safe conditions in the event that the operational parameters have an abnormal deviation from the design values. Also the entire power system has been designed so that any failure to its components does not compromise the workers’ safety even if the risk analysis is in progress because technical operations are being carried out for enhancing the plant functionality, making it more suitable to the designed task of supplying electrically the greenhouse heating system during cold periods. Some experimental data pertinent to the solar radiation and the corresponding hydrogen production rate are also reported. At present it does not exist a well-established safety reference protocol to design the reliability of these types of power plants and then the assumed safety measures even if related to the achieved pilot installation, can represent an original base of reference to set up guidelines for designing the safety of power plants in the future available for agricultural purposes.

The focus of this paper is on the energy performance and thermo-economic assessment of a small scale (100 kWe) combined cooling, heat and power (CCHP) plant serving a tertiary/residential energy demand fired by natural gas and solid biomass. The plant is based on a modified regenerative micro gas-turbine (MGT), where compressed air exiting the recuperator is externally heated by the hot gases produced in a biomass furnace. The flue gases after the recuperator flow through a heat recovery system (HRS), producing domestic hot water (DHW) at 90 °C, space heating (SH), and also chilled water (CW) by means of an absorption chiller (AC). Different biomass/natural gas ratios and an aggregate of residential end-users in cold, average and mild climate conditions are compared in the thermo-economic assessment, in order to assess the trade-offs between: (i) the lower energy conversion efficiency and higher investment cost when increasing the biomass input rate; (ii) the higher primary energy savings and revenues from feed-in tariffs available for biomass electricity exported into the grid; and (iii) the improved energy performance, sales revenue and higher investment and operational costs of trigeneration. The results allow for a comparison of the energy performance and investment profitability of the selected system configuration, as a function of the heating/cooling demand intensity, and report a global energy efficiency in the range of 25-45%, and IRR in the range of 15-20% assuming the Italian subsidy framework.

The use of plastic materials in agriculture, for greenhouse covering, soil mulching, irrigation pipes, containers and bags, generates a huge amounts of plastic waste that must be properly disposed of. An adequate waste management and disposal system requires the knowledge of the waste generation on the land. This paper presents the results of a research, based on the application of a Geographical Information System, for mapping the waste generation in the municipality of Trinitapoli, Italy. Aim of the research is to identify the points of waste generation and to quantify the waste. A dedicated geo-referenced database with data on the spatial distribution and amount of the plastic wastes was created; waste density ranged from 3.3 kg ha-1yr-1 to 861 kg ha-1yr-1. L’uso di materiali plastici in agricoltura, quali film per la copertura di serre, film per la pacciamatura del terreno, tubi d’irrigazione, contenitori di pesticidi e sacchetti di fertilizzanti, genera un enorme quantita di rifiuti plastici che devono essere correttamente smaltiti. Un sistema adeguato di gestione e smaltimento delle plastiche presuppone la conoscenza della produzione dei rifiuti sul territorio. Questo lavoro presenta i risultati di una ricerca, basata sull’applicazione di un Sistema di Informazione Geografica, per la mappatura della produzione di rifiuti nel comune di Trinitapoli, in Italia. Lo scopo della ricerca e quello di identificare i punti di generazione dei rifiuti plastici e di quantificarli. E stato creato un database georeferenziato dedicato, con i dati sulla distribuzione spaziale e la quantita di rifiuti di plastica generati. La densita dei rifiuti prodotti varia da 3,3 kg ha-1 a 861 kg ha-1 per anno.

The environmental impact and the cost of fossil fuel system for greenhouse heating are the major limits for the development of protected horticulture. Recent researches are focusing on greenhouses optimal climate control and reduction of energy consumption. The use of suitable microclimate control systems, energy efficiency strategies and renewable energy sources could improve the environmental performance of the greenhouses. Renewable energy sources can be used to produce hydrogen by electrolysis with very high gas purity. Hydrogen can serve the purpose of storing overproduced energy after meeting the requirements of the greenhouse, and later it can be employed as fuel, achieving a stand-alone power system. Therefore a research is under development at the University of Bari in order to investigate the suitable solutions of a power system based on solar energy (photovoltaic) and hydrogen, integrated with a geothermal heat pump for powering a self sustained heated greenhouse. The tests were carried out at the experimental farm of the University of Bari sited in Valenzano, Bari, Southern Italy, latitude 41° N, where two experimental greenhouses, with the same geometric and constructive characteristics, have been realized; the distance between the two greenhouses is 12 m; therefore there is no mutual shading. One of the two greenhouses is heated using a low enthalpy heat pump combined with a vertical ground heat exchanger, in comparison with the other unheated greenhouse. The electrical energy for heat pump operation is provided by a purpose-built array of solar photovoltaic modules, which supplies also a water electrolyser system controlled by embedded pc; the generated dry hydrogen gas is conserved in suitable pressured storage tank. The hydrogen is used to produce electricity in a fuel cell in order to meet the above mentioned heat pump power demand when the photovoltaic system is inactive during winter night-time or the solar radiation level is insufficient to meet the electrical demand of the heat pump during overcast cold sky. This note reports the main elements regarding the integrated system design and building and it shows preliminary results of testing operation.

In order to evaluate the influence of the texture characteristics of agricultural nets on the air flow passing through them, a micro wind tunnel was designed and built in the testing and engineering laboratory of Sachim s.r.l., an Italian high-density polyethylene (HDPE) technical textiles manufacturer. The micro wind tunnel (0.1345 m diameter) allowed the simultaneous measurement of the air flowrate and the pressure drop through a net sample. The equipment was designed to set up the inclination of the net samples with respect of the airflow at fixed angles (90°, 60°, 45°, 30°). The variation of the pressure drop with the air velocity on four different flat woven round monofilament HDPE nets perpendicular to the air flow are here reported. In all cases the air velocity measured into the micro wind tunnel was above 4 m s–1 hence reported results do not consider low wind speed. Preliminarily, the loss coefficient was assumed as a function of porosity and Reynolds number, calculated with reference to the equivalent diameter of the pores, FS(Rel,ε) and showed percent deviations form experimental results in the range 14.6%÷25.3%. Hence a simplified expression of the loss coefficient, depending only on the porosity was proposed, FS(ε) which highlighted differences with experimental results in the range 3.5%÷20.3%. Finally, results were compared with those based on the Bernoulli’s principle found in the literature.

In Italy, a large number of agricultural areas are contaminated by organic and inorganic polluting substances. In such areas, the agricultural operators come into contact with the environmental contaminants through inhalation and dermic contact with dusts and vapour, and this exposure can potentially alter the biological equilibrium with consequent poisonings and/or work-related illness. The aim of this paper is to apply a methodological procedure for the numerical evaluation of the health risk for agricultural employees operating in open fields or inside greenhouses located in areas contaminated with organic pollutants. This procedure is in response to the lack of calculation models concerning these types of environment and agricultural activities. As a case study, this methodology has been applied to an agricultural area of southern Italy characterised by the presence of pollutants. The results underline that in this area there is a smaller concentration of pollutants in open field cultivations than inside greenhouses owing to a phenomenon of dispersion into the atmosphere. This numeric analysis will later be verified by measurements carried out in situ in order to evaluate the real situation on the ground.