583 research outputs found

    Non-technological barriers to the diffusion of energy-efficient HVAC&R solutions in the food retail sector

    Get PDF
    SuperSmart is an European Union (EU) project aiming at speeding up the uptake of energy-efficient re- frigeration, heating and cooling solutions for Europe\u2019s food retail sector, reducing its energy use, lowering its environmental footprint and increasing its economic benefits. The project pursues the removal of non- technological barriers to efficient heating & cooling in the European food retail sector and supports the introduction of a new EU Ecolabel for food retail stores. Non-technological barriers have been mapped and categorized by preliminary interviewing food re- tail sector stakeholders. While highlighting a general positive attitude towards energy efficiency of the sector stakeholders, the results of the survey reveal the need for specific actions focused on improving the knowledge level of technical staff, from the planning and design stage down to servicing and main- tenance. Raising awareness about available technology and financial support is also required. In general terms, barriers are always perceived as stronger when moving North to South, and West to East in Europe, thus emphasizing the need for homogenization of virtuous practices and attitudes throughout Europ

    Biogas Engine Emissions: Standards and On-Site Measurements

    Get PDF
    Abstract The European Union, with 60% of the total global production of biogas, is the world leader. In 2012, the percentage of electrical energy produced by biogas was 6% of the EU-28 electricity generated through renewable sources while, in 2013, the almost 830 biogas units produced 7448 GWh which corresponds to 14% of EU-28 gross electricity production. Germany, U.K. and Italy are the main EU biogas producers with over 78% of the 2013 primary energy production. Electricity production is the main biogas energy recovery form because the engine cooling water is used to maintain the digester required temperature while energy crops and manure are the most used organic matters. Spark-ignition engines with a rated power of 1MWel in which the filtered biogas is burned to produce work is the widely-adopted technology. With the aim of analyzing the emissions of a real biogas engine, in the present work, the authors firstly present an overview of the Italian biogas sector and the most used conversion technologies. Then, the standards which regulate the biogas plant emissions and the emissions data acquired during a one-year monitoring activity on 10 biogas plants are presented and discussed with the aim of assessing the biogas units' real emissions

    Infrared thermography-calorimetric quantitation of energy expenditure in biomechanically different types of jĆ«dƍ throwing techniques: a pilot study

    Get PDF
    It was the purpose of this pilot study to assess the energy expenditure (EE) of two biome-chanically different jĆ«dƍ throws, namely, the simple mechanical couple-based uchi-mata vs. the lever-based throw ippon-seoi-nage, using infrared thermal calorimetry (ITC). Testing subjects included one Caucasian female elite athlete (age: 26.4 years) and one male veteran jĆ«dƍka (age: 50.8 years). ITC images were captured by an Avio NEC InfRec R300 camera and thermal data obtained were plotted into a proprietary equation for estimation of EE. Data were compared to respiratory data obtained by a Cosmed K4 b2 portable gas analyzer. Oxy-gen consumption as estimated by ITC capture during practice of uchi-mata was markedly lower than during performance ippon-seoi-nage in the female (457 mL‱min-1 vs. 540 mL‱min-1, P<0.05) and male subject (1,078 mL‱min-1 vs. 1,088 mL‱min-1, NS), with the difference in values between both genders subject being significant (P<0.01). The metabolic cost of the exercise (uchi-mata vs. ippon-seoi-nage) itself was 1.26 kcal‱min-1 (88 W) vs. 1.68 kcal‱min-1 (117 W) (P<0.05) in the female subject, and 2.97 kcal‱min-1 (207 W) (P<0.01) vs. 3.02 kcal‱min-1 (211 W) (NS) in the male subject. Values for the female were significantly differ-ent (P<0.01) from those of the male subject. The results support the initial hypothesis that the couple-based jĆ«dƍ throws (in this case, uchi-mata) are energetically more efficient than lever-based throws, such as ippon-seoi-nage. Application of this approach may be of practical use for coaches in optimizing energy-saving strategies in both elite and veteran jĆ«dƍ athletes

    Exploiting diluted bioethanol solutions for the production of ethylene: Preliminary process design and heat integration

    Get PDF
    Several activity tests on a zeolite-based catalyst for the ethanol to ethylene dehydration reaction are used to outline the stoichiometry of 4 reactions describing the observed outcome. The heat and mass balances of a reactor were calculated. The thermal input was mainly sustained with a standard product-to-feed heat exchange. Upstream, two possible strategies of ethanol-water beer concentration were compared, namely a single stage flash and a small column, yielding respectively a 3:1 water:ethanol mixture and a slightly diluted azeotrope. The external heat input needed for the separation unit, the feed heating up to the reaction temperature and the reaction upkeep are compared. A flow diagram for the hot utility is then designed, converting part of the water of the beer into superheated steam that gives also electric power. The conceptual design of an ethanol to ethylene plant is therefore available to exploit bioethanol solution with different water/ethanol ratios, with different ethanol purification routes with variable heat input and energy recovery

    Flow network indices signal a directional change in ecosystems: Evidence from a small mountain lake (Lake Santo, northern Italy)

    Get PDF
    Empirical evidence of the theoretically expected trends of ecosystem development is scarce so far. In this research, we used long-term empirical data about the plankton community of a small mountain lake (Lake Santo, northern Apennines, Italy) to reconstruct its developmental trajectory during a period comprised between early 1970 s and 2010 s. We exploited these data to build yearly ecological networks and from their configuration of energy flows we computed network information indices. The trends of these indices enlighten about the developmental trajectory of this ecosystem during the period covered by the data set. In particular, they indicate that Lake Santo evolved in the direction of increasing stability at the expense of efficiency in energy transfer. We compared these results with current hypotheses about the directionality of ecosystem development, which are rooted in ecosystem theory, and discussed the possibility that, counter to some theoretical models of ecosystem development, Lake Santo followed an unimpeded direction of development rather than a trajectory typical of an ecosystem under stress. Finally, the long-term trends of flow network indices provided insights about the health status of the ecosystem

    study and simulation of a hydraulic hybrid powertrain

    Get PDF
    Abstract In the agricultural and work machine sectors, the hydro-mechanical transmission competes with traditional mechanical transmission; a tool to improve its competitiveness is the hybridization. The hydraulic branch of the transmission may be integrated with two accumulators which allow the storage of energy derived from braking; the presence of the two hydraulic units facilitates this solution: the hydraulic motor acts as a pump during the braking and as a motor during the starts of the vehicle. This solution appears to be interesting also from the costs point of view, because it does not require a high-level technology. For this reason, in the present work, the hybrid hydro-mechanical transmission is studied with the aim of pointing out its potential for the urban passenger transport sector. At first, a hydro-mechanical transmission for an urban bus is designed; then, the same transmission is modified adding the components for the hydraulic hybridization. After that, the two vehicles is modelled and simulated using the AMESim code, and, finally, compared to each other in terms of energy savings

    Process simulation for the design and scale up of heterogeneous catalytic process: Kinetic modelling issues

    Get PDF
    Process simulation represents an important tool for plant design and optimization, either applied to well established or to newly developed processes. Suitable thermodynamic packages should be selected in order to properly describe the behavior of reactors and unit operations and to precisely define phase equilibria. Moreover, a detailed and representative kinetic scheme should be available to predict correctly the dependence of the process on its main variables. This review points out some models and methods for kinetic analysis specifically applied to the simulation of catalytic processes, as a basis for process design and optimization. Attention is paid also to microkinetic modelling and to the methods based on first principles, to elucidate mechanisms and independently calculate thermodynamic and kinetic parameters. Different case studies support the discussion. At first, we have selected two basic examples from the industrial chemistry practice, e.g., ammonia and methanol synthesis, which may be described through a relatively simple reaction pathway and the relative available kinetic scheme. Then, a more complex reaction network is deeply discussed to define the conversion of bioethanol into syngas/hydrogen or into building blocks, such as ethylene. In this case, lumped kinetic schemes completely fail the description of process behavior. Thus, in this case, more detailed\ue2\u80\u94e.g., microkinetic\ue2\u80\u94schemes should be available to implement into the simulator. However, the correct definition of all the kinetic data when complex microkinetic mechanisms are used, often leads to unreliable, highly correlated parameters. In such cases, greater effort to independently estimate some relevant kinetic/thermodynamic data through Density Functional Theory (DFT)/ab initio methods may be helpful to improve process description

    994-98 Patients’ Radiation Risk During Diagnostic and Interventional Coronary Procedures

    Get PDF
    Uncertainties in radiation risk estimates at low doses (&lt;0.1Gy) include the shape of the dose-response curve, use of a relative or absolute risk model, and the length of the latent cancer induction period. Coronary procedures are often repeated within short in many patients, but neither absorbed doses nor imparted energies are routinely measured. We used LiF thermoluminescence dosimeters in 15 consecutive diagnostic (D) and 15 PTCA (1) procedures, with stent implantation in 1 case, multivessel PTCA in 2, and PTCA of chronic occlusion in 2. A Philips Optimus 2000 DCI was used, with a standard dose of 10microR/f for an image intensifier format (lIF) of 23cm. Fluoroscopy times (2.9±1min for D and 16±6min for I) number of cine runs (9±2 for D and 17±7 for I) and length of cine runs (5.3±1.5sec for D and 2.9±2sec for I) were representative of our standard procedures. A rate of 12.5f/s was used for cine coronary imaging, with 25f/s for left ventriculograms in 2 projections. IIF 18 and 13cm were used for D and I, respectively. Patient absorbed doses (mGy) were [mean±s.d.(range)]:ThyroidR+L Thorax/2ColumnGonadsD0.6±0.318±27 (1.3–127)21±360.08±0.05I2.0±0.829±50 (1.2–245)26±190.08±0.02Patient radiation exposure during D and I, despite dose-effective technique, is substantial, especially in areas (thorax) which cannot be shielded. It should be routinely measured since radiation risk may not be negligible when repeated procedures are performed. The risk/benefit ratio of repeated D and I must be weighed

    Experimental evaluation of the performance of an ejector for a single compression multi-temperature CO2 refrigeration unit

    Get PDF
    A novel vapor-compression system concept employing carbon dioxide as the refrigerant is proposed to serve the needs of a typical medium-size refrigerated truck used for multi-temperature (MT and LT) goods delivery. The system design is based on the implementation of an ejector as the only component increasing the refrigerant pressure from the LT evaporation pressure to the MT evaporation pressure, thus allowing the realization of a unit providing cooling effect at two different temperature levels with only one stage of compression. The ejector was experimentally tested in order to evaluate its ability to effectively entrain mass flow rate from very low pressure conditions at the suction nozzle, corresponding to the LT evaporator outlet conditions. In addition, a simple preliminary thermodynamic evaluation of tExperimental evaluation of the performance of an ejector for a single compression multi-temperature CO2 refrigeration unitacceptedVersio

    Improving the Quality of Milk Fatty Acid in Dairy Cows Supplemented with Soybean Oil and DHA-Micro Algae in a Confined Production System

    Get PDF
    The objective was to reduce saturated fatty acids (SFA) and increase conjugated linoleic acid (CLA, cis- 9, trans -11 C18:2), α-linolenic (cis- 9, cis- 12, cis- 15 C18:3) and docosahexaenoic (DHA, C22:6) contents in milk from confined dairy cows in order to promote a healthier option. The work was carried out in a commercial farm (Talar) located in Laguna del Sauce, Maldonado (Uruguay). Twenty four cows were assigned to one of two treatments (12 cows per treatment) over a 6 weeks experimental period. Treatments consisted in a control total mixed ration (C-TMR) without supplementary lipids (L) or the same TMR with the addition of 0.144 kg/cow∙day of algae and 0.72 kg/cow∙day of soybean oil (L-TMR). Chemical composition of the TMR (44.27% DM) averaged 15.94% for crude protein (CP), 38.20% neutral detergent fiber (NDF), 20.36% acid detergent fiber (ADF), 5.56% fat, 5.30% ash and 28.6% nonstructural carbohydrate (NSCH) with 1.81 Mcal/kg of net energy for lactation (NEL). After 39 days of feeding, individual milk samples were collected during three consecutive days. From the total milk collected, 20 ml were immediately used for chemical composition (Milko Scan) and 80 ml for analysis for milk FA profile. From week 3 onwards, milk production (kg/cow∙day) resulted higher (P < 0.001) in L-TMR (36.9) compared to C-TMR (35.2). At week 6 of trial, the difference in milk production averaged 5.14% for L-TMR. Supplementary lipids reduced (P < 0.002) milk fat concentration (g/100g) from 3.36 in C-TMR to 2.40 in L-TMR without effect (P = 0.43) on milk protein content (C-TMR = 3.20; L-TMR = 3.07 g/100g). Milk lactose (C-TMR = 4.86, L-TMR = 4.69 g/100g) and urea nitrogen contents (C-TMR = 21.18, L-TMR = 17.33 g/100g) tended (P < 0.056) to decrease in L-TMR as well as fat corrected milk output (C-TMR = 30.89, L-TMR = 29.49 kg/cow∙day, P < 0.098). Lipid supplementation reduced (−23%) milk content of C12:0 to C16:0 FA averaging 45.19 in C-TMR and 34.74 g/100g in L-TMR (P < 0.001). The atherogenic index (AI) of milk decreased (P < 0.001) from 2.69 in C-TMR to 1.50 in L-TMR (−44.2%). Concentration (g/100g) of elaidic (C18:1 trans -9) (0.23) and C18:1 trans -10 (0.44) FA increased (P < 0.001) in L-TMR milk. Milk vaccenic acid (trans- 11 C18:1, VA) increased from 1.08 in C-TMR to 2.56 g/100g of FA in L-TMR (P < 0.001). Milk CLA content (cis- 9, trans- 11 C18:2) increased (127%) from 0.62 in C-TMR to 1.41 g/100g FA in L-TMR milk. Content of α-linolenic acid resulted 20% higher (P < 0.001) in L-TMR milk (0.35 g/100g FA) compared to C-TMR (0.30 g/100g FA). Milk DHA increased from 0 in C-TMR to 0.14 g/100g FA in L-TMR. The omega-6/-3 ratio in C-TMR milk (9.61) was reduced (P < 0.001) to 6.78 in L-TMR milk. Milk oleic acid (cis -9 C18:1) resulted higher (P < 0.001) in L-TMR (23.65) than in C-TMR (19.75 g/100g FA). The nutritional value of milk fat from confined cows was naturally improved by feeding polyunsaturated FA in the ration, obtaining a reduction of saturated FA and increased levels of healthy FA (CLA, DHA and α-linolenic).Fil: Gagliostro, Gerardo Antonio. Instituto Nacional de TecnologĂ­a Agropecuaria (INTA). EstaciĂłn Experimental Balcarce. Area de ProducciĂłn Animal; Argentina.Fil: Antonacci, Liliana Elisabet. Instituto Nacional de TecnologĂ­a Agropecuaria (INTA). EstaciĂłn Experimental Balcarce. Area de ProducciĂłn Animal; Argentina.Fil: Perez, Carolina Daiana. Instituto Nacional de TecnologĂ­a Agropecuaria (INTA). Instituto TecnologĂ­a de Alimentos; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina.Fil: Rossetti, Luciana. Instituto Nacional de TecnologĂ­a Agropecuaria (INTA). Instituto TecnologĂ­a de Alimentos; Argentina.Fil: Carabajal, Augusto. Establecimiento Agroindustrial Talar. Laguna del Sauce. Departamento de Maldonado; Urugua
    • 

    corecore