4,134 research outputs found

    Heat Pumping and Reversible Air Conditioning: How to make the best use of HVAC equipment ?

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    peer reviewedIEA-ECBCS Annex 48 - Heat Pumping and Reversible Air Conditionin

    Méthode des éléments discrets : des problèmes multi-corps aux problèmes d’endommagement dynamique complexes.

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    La méthode des éléments discrets est présentée comme une alternative aux approches de type mécanique des milieux continus pour aborder certains aspects liés aux problèmes dynamiques, notamment la multi fracturation de matériaux fragiles. Des exemples liés à l’usinage des composites et au surfaçage du verre sont présentés. Une extension de la méthode pour étudier le comportement des mousses est ensuite proposée et imagée par des premiers résultats

    A Computer Vision System to Localize and Classify Wastes on the Streets

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    Littering quantification is an important step for improving cleanliness of cities. When human interpretation is too cumbersome or in some cases impossible, an objective index of cleanliness could reduce the littering by awareness actions. In this paper, we present a fully automated computer vision application for littering quantification based on images taken from the streets and sidewalks. We have employed a deep learning based framework to localize and classify different types of wastes. Since there was no waste dataset available, we built our acquisition system mounted on a vehicle. Collected images containing different types of wastes. These images are then annotated for training and benchmarking the developed system. Our results on real case scenarios show accurate detection of littering on variant backgrounds

    Simulation Based Assessment of Heat Pumping Potential in Non-Residential Buildings – Part 3: Application to a typical office building in Belgium

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    peer reviewedThe purpose of this paper is to describe the application of the tools presented in a companion paper [1] to a typical office building located in the Walloon Region of Belgium. This building is a mid-size (7000 m² on seven floors) office building constructed in the eighties and equipped with a classical HVAC solution: boiler and air-cooled chiller; all-air VAV system. An energy audit was conducted in this building and featured a number of management problems. Among the Energy Conservation Opportunities considered to improve the energy performance of the building, the move to a heat pump solution was considered. The identification of energy savings potential offered by the implementation of heat pumping strategies confirmed what was already shown by the parametric analysis: in temperate climates, reversibility offers a by far higher potential than condenser heat recovery given the dominant non simultaneity of the yearly heating and cooling demands profiles. Calculations show that theoretically half of the heating demand could be satisfied by the reversibility of the chiller to run in heat pumping mode. In a second step, a number of practical implementations of heat pumping solutions were evaluated by means of another software tool: reversible air/water HP, exhaust air HP, double condenser and water loop heat pump systems. These solutions are compared to the reference existing situation (boiler + chiller working independently) in terms of energy, CO2 emissions and cost on a 20 years life-cycle basis. Calculations show that the air/water reversible chiller solution offers the most important energy savings and CO2 reduction while staying at a reasonable level concerning the additional cost.IEA-ECBCS Annex 4

    An assessment of the benefits of yellow Sigatoka (Mycosphaerella musicola) control in the Queensland Northern Banana Pest Quarantine Area

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    The banana leaf spotting disease yellow Sigatoka is established and actively controlled in Australia through intensive chemical treatments and diseased leaf removal. In the State of Queensland, the State government imposes standards for de-leafing to minimise the risk of the disease spreading in 6 banana pest quarantine areas. Of these, the Northern Banana Pest Quarantine Area is the most significant in terms of banana production. Previous regulations imposed obligations on owners of banana plants within this area to remove leaves from plants with visible spotting on more than 15 per cent of any leaf during the wet season. Recently, this leaf disease threshold has been lowered to 5 per cent. In this paper we examine the likely impact this more-costly regulation will have on the spread of the disease. We estimate that the average net benefit of reducing the diseased leaf threshold is only likely to be $1.4 million per year over the next 30 years, expressed as the annualised present value of tightened regulation. This result varies substantially when the timeframe of the analysis is changed, with shorter time frames indicating poorer net returns from the change in protocols. Overall, the benefit of the regulation change is likely to be minor

    Emissions of Carbonaceous Particulate Matter and Ultrafine Particles from Vehicles-A Scientific Review in a Cross-Cutting Context of Air Pollution and Climate Change

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    Featured Application Key conclusions and recommendations are proposed to enlighten decision makers in view of the next regulations on vehicle emissions in Europe and worldwide through the synergistic contexts of air quality and climate change. Airborne particulate matter (PM) is a pollutant of concern not only because of its adverse effects on human health but also on visibility and the radiative budget of the atmosphere. PM can be considered as a sum of solid/liquid species covering a wide range of particle sizes with diverse chemical composition. Organic aerosols may be emitted (primary organic aerosols, POA), or formed in the atmosphere following reaction of volatile organic compounds (secondary organic aerosols, SOA), but some of these compounds may partition between the gas and aerosol phases depending upon ambient conditions. This review focuses on carbonaceous PM and gaseous precursors emitted by road traffic, including ultrafine particles (UFP) and polycyclic aromatic hydrocarbons (PAHs) that are clearly linked to the evolution and formation of carbonaceous species. Clearly, the solid fraction of PM has been reduced during the last two decades, with the implementation of after-treatment systems abating approximately 99% of primary solid particle mass concentrations. However, the role of brown carbon and its radiative effect on climate and the generation of ultrafine particles by nucleation of organic vapour during the dilution of the exhaust remain unclear phenomena and will need further investigation. The increasing role of gasoline vehicles on carbonaceous particle emissions and formation is also highlighted, particularly through the chemical and thermodynamic evolution of organic gases and their propensity to produce particles. The remaining carbon-containing particles from brakes, tyres and road wear will still be a problem even in a future of full electrification of the vehicle fleet. Some key conclusions and recommendations are also proposed to support the decision makers in view of the next regulations on vehicle emissions worldwide

    Verification of the Energy Balance of a Passive House by Combining Measurements and Dynamic Simulation

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    AbstractPassive houses have, at design stage, to fulfill a number of performance criteria. One of them imposes the normalized theoretical heat demand to be limited to 15 kWh/m2, year. In operation, it is very difficult to check, from simple observations or measurements, the real performance of such a house: different energy vectors may be used to meet the space heating as well as the domestic hot water demand, a storage tank may be used and fed by different energy sources (heat pump, direct electricity, solar thermal). The problem is still more complicated if the house is equipped with PV panels which naturally decrease the apparent electrical consumption. In the frame of the IEA Annex 58 project, a passive house was the object of a detailed analysis aiming at estimating the different terms of the energy balance. Some terms were results of direct in situ measurements and unmeasured terms such as solar and internal gains were estimated by dynamic simulation. The combination of measurements and simulation results allowed a reconstruction of a robust energy balance. The paper provides a detailed description of the approach and of each term of the rebuilt energy balance
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