• Energy Research
• 13. Climate action close
• Energy Procedia close
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AbstractEnvironment respect makes both the Legislator ever more careful to define urgent emissions limits than each one responsible to find the best technological and behavioral solutions. The works includes the results of combustion simulations in a MGT burner. The purpose is to verify combustion performances of some between classic and renewable fuels, with a view to design choices. The approaches: a “Laminar Flamelet” model and, especially to verify simply kinetic influences, a partially premixed model.

Abstract To improve food security a conceptual integration beyond the scope of production in the agricultural sector due to examination of critical supply chain system compartments and levels of services (“integrated food production and supply systems”) is proposed. For creating systematic results, a platform integrating various perspectives of experts has been established following the principle of triple helix stakeholdership (business practice, public management/policy and also science). During a series of workshops, the main actors, success factors, challenges and communication strategies have been identified for shaping sustainable food supply chains under use of systems thinking and the application of Participatory Systems mapping (PSM). In this line, the paper presents how “system maps” based on the method of PSM are used to gain insights into sustainable logistics services facilitating sustainable consumption patterns, enabling participatory considerations and the productive exchange of knowledge.

Abstract The environmental concerns due to global warming are pushing A/C industries to new eco-friendly refrigerants in several fields. In this paper a model to simulate the dynamic evolution of the temperature inside an air-conditioned high-speed train compartment is presented. The dynamic modeling of both the reversible heat pump unit and the thermal loads of the cabin are presented, including the possibility of adapting the frequency of the compressor and the return air fraction for maintaining the internal comfort conditions. Under different dynamic load conditions (in terms of ambient temperature, solar radiation, train speed, number of passengers) the energy consumptions and the TEWI related to the use of new refrigerants, (like R1234yf and R1234ze), are calculated being the R134a a baseline for comparison.

Diesel engines are worldwide used as a primary power source not only in motor vehicles, but also in off-road engine applications. Two-stroke Diesel engine is most commonly seen in applications demanding a large power output, such as ships and electric generation plants. The use of biofuels has increased during the last years in response to concerns about climate change and to increase security of supply. In this paper some results obtained with a 2-Stroke 6V53 Detroit Diesel (5.22L displacement, 150kW at 2800rpm) fueled with a commercial diesel fuel and biodiesel (100%RME) are discussed. CO, NO/NOx, CO2 and particulate matter (PM) have been sampled at 1 Hz in different load conditions and fuel consumption has been measured. A catalyzed Diesel particulate filter (DPF) has been also installed at the exhaust to reduce PM emissions and the influence of fuel quality on emissions and fuel consumption was analyzed. The installation of DPF has involved an average of less than 10% fuel economy penalty for both tested fuels. A passive DPF system can be easily installed at the exhaust of in-use engine and it permits to reduce more than 90% PM emissions.

AbstractThe growing of the energy consumption, in particular from buildings, both residential and commercial has induced a major interest for the analysis of the seasonal performance of heat pumps. The same considerations are effective for the well-known environmental problems related to direct and indirect emissions of carbon dioxide into the atmosphere and the incentives to support energy efficiency. In this work an air to water heat pump working with R290 and HFO1234yf has been modeled and simulated using the software package IMST-ART in order to evaluate the seasonal performance. Two different types of applications were considered: fan coils and radiant heat floor panels. Different types of building are considered. The seasonal performance in heating mode, SCOP, is calculated by coupling the performance of the heat pump in different operative conditions to a heating demand curve, in two different climate zones (average and colder). The results of the simulations show better performance of the heat pump with propane in both climates and applications, which is probably due to the state of current technology of the different components. In particular, the global performance of the compressor working with R1234yf is not yet optimized. At the same time a new design of the evaporator is desirable to reduce the pressure drops with R1234yf.

Abstract In this work, a new approach for the design of air conditioning systems with cold thermal energy storage is described and tested, considering the case study represented by a vapor-compression chiller, coupled with a chilled water storage system, producing cooling for a small multi-apartment building situated in Italy. In the present approach, at the aim of limiting shut-downs and start-ups of the chiller, which involve inefficiencies during transients, and can lead to a drastic reduction of the equipment lifetime, the nominal power of the chiller, and the amount of cooling to be stored are first estimated in a pre-design phase. Successively, the outputs of the pre-design are used to fix the size of the cold storage tank, and to set up the numerical simulation of the cold thermal energy storage system. Finally, the results of the numerical simulation of the cold storage system are used to evaluate the effective size of the chiller. Both the pre-design and the numerical simulations of the cold storage systems have been done by means of home-made numerical tool realized with Simulink. In the paper, the specifications relative to the operational strategy are explored, and the analytical models used for the numerical simulation of the cold storage system relative to the Italian case study are reported in detail. Finally, the results of the pre-design, and of the cold storage system simulations relative to the case study are presented and discussed. The results relative to the Italian case study demonstrates the effectiveness of the present approach in limiting the number of shut-downs and start-ups of the chiller. The present approach can represent a useful tool for the economic optimization of the design of air conditioning systems.

AbstractThe atmospheric photo-oxidation of 2-aminoethanol (MEA, NH2CH2CH2OH) was studied at the European Photochemical Reactor, EUPHORE, in Valencia (Spain). The experiments were carried out under different atmospherically relevant NOx conditions. The photo-oxidation was monitored in situ by FT-IR and on-line by PTR-TOF-MS, and samples were collected on various adsorbents for subsequent off-line analysis. The formation of particles was monitored by SMPS and AMS on-line instruments and filter sampling followed by LC/HRMS(TOF) analysis. The obtained results suggest that more than 80% of the reaction between MEA and OH radicals takes place at–CH2–, while less than 10% occurs at–NH2 and at–CH2OH, respectively. The major observed products (>80%) in the photo-oxidation were formamide (NH2CHO) and formaldehyde (CH2O). Minor detected products (<10%) were amino acetaldehyde (NH2CH2CHO) and 2-oxo acetamide (NH2C(O)CHO). 2-nitroamino ethanol, O2NNHCH2CH2OH, was confirmed as product in the experiments.

Abstract Energy supply sustainability is a multifaceted challenge for all countries and especially for small island nations that might have limited adaptive capacity. Previous studies showed that islands experience energy scarcity and isolation from energy markets due to their remote location. Our focus is on a range of islands spread out globally: Malta, Cyprus, Curacao, Mauritius, Iceland, Jamaica, Trinidad and Tobago and Bahrain. They are selected for their varying energy development paradigms that facilitate cluster elicitation. For the first time, we combine the estimation of fuel mix diversity and energy import dependence with established metrics Shannon-Wiener index (SWI), Herfindahl-Hirschman index (HHI) and Energy Import Dependence to assess energy supply security. SWI and Energy Import Dependence are then presented against carbon intensity to highlight two angles of sustainable energy supply. We argue that islands are clustered to those that have fossil fuel reserves and are locked in low diversity, low dependence and high carbon intensity, those that rely almost exclusively on imported fossil fuel reserves and have low diversity and high dependence and high carbon intensity and finally those that have entered a decarbonization trajectory that allows them to reduce their fossil fuel import dependence, increase their diversity and reduce their carbon intensity.

Abstract The authors discuss in this paper the potential of a micro gas turbine (MGT) combustor when operated under unconventional conditions, in terms of variation in the fuel supplied. The authors’ expertise in the field of micro-combustor has addressed, in recent years, some topics of current interest, as the fuelling with gaseous and liquid biofuels and the NOx reduction through the optimization of the combustor. While the previous authors’ works were mainly referring to a tubular combustor of a 100kW MGT, the present proposal deals with an annular, reverse flow combustor of a 30kW MGT. In this case the particular location of both the injectors and of the secondary and diluting holes allows the combustor process to develop under nearly RQL conditions. This is of special interest when supplying the combustion chamber with low LHV fuels. In addition, recent authors’ papers have demonstrated that the integration of the MGT with a solar field leads the combustor to require a decreased fuel/air equivalence ratio because of the higher air entry temperature. Under these aspects, the existence of a Rich region within the combustor may be helpful for the early phases of the oxidation process. The pollutant formation rates should be effectively controlled by the secondary (Quick-mix) and diluting (Lean) air flows. The authors’ methodology relies on an advanced CFD approach that makes use of a reaction scheme coupled with an accurate study of the turbulent interaction of the reacting species. Extended kinetic mechanisms are also included in the combustion model. A preliminary set-up of the model will be based on the combustion analysis with boundary conditions provided by thermodynamic analysis of the micro-turbine. Several computational examples are discussed, namely: - The analysis of the combustor response with reduced equivalence ratios or changes in the inlet air conditions; - The comparison of combustion efficiency and pollutant production with different fuels.

AbstractThe study proposes a comparison between the thermal performances of a real building, built according to the German standard DIN 4108-2:2003, and a refurbished one (in a theoretical investigation), aimed at satisfying the more restrictive requirements of the new version (i.e., 2013) of the same standard. The analysed building, completed during the 2012, is located in Berlin. The building has good performances in terms of energy demand for heating. Diversely, during the first years of operations, some overheating problems have been verified in summer. Because of sustainability motivations, cooling devices are not installed. An energy-oriented retrofit is here proposed, aimed at verifying if the fulfillment of the new version of the DIN 4108-2:2013 will produce better microclimatic conditions in summer. The results show the necessity of an accurate approach to the topic of summer thermal protection.