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  • 201.
    Wang, Chengju
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Energy use and energy saving in buildings and asthma, allergy and sick building syndrome (SBS): a literature review2019Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Energy use in buildings is an important contribution to global CO2 emissions and contributes to global warming. In recent years, there has been concern about creating energy efficiency buildings, green buildings and healthy buildings but this development needs guidance by multidisciplinary scientists and experts. Since energy saving can influence the indoor environment in different ways, epidemiological research is needed in different climate zones to evaluate the health consequences of making the buildings more energy efficient. Epidemiological studies and modelling studies are available on health effects and indoor effects of energy conversation, improved thermal insulation, increased air tightness and creating green buildings. The health-related literature on this issue was reviewed, by searching scientific articles in the medical Database PubMed and in the general database Web of Science as well as Nature database. In this literature review, 53 relevant peer reviewed articles on health effects of energy use and energy saving were found. Most of the studies had investigated residential buildings. One main conclusion from the review is that combined energy efficiency improvements in buildings can be associated with improvement of general health, such as less asthma, allergies, sick building syndrome (SBS) symptoms, respiratory symptoms, and reduced cold-related and heat-related mortality. Moreover, combined energy efficiency improvements can improve indoor air quality, increase productivity and satisfaction and reduce work leave and school absence. Effective heating of buildings can reduce respiratory symptoms and reduce work leave and school absence. However, some potential health problems can occur if increased energy efficiency will reduce ventilation flow. Energy saving by increasing air tightness or reducing ventilation is associated with impaired indoor air quality and negative health effects. In contrast, improved ventilation may reduce SBS, respiratory symptoms and increase indoor air quality. Installation of mechanical ventilation can solve the negative effects of making the building construction in dwellings more air tight. In future research, more studies are needed on health impacts of single energy efficiency improvement methods. Existing studies have mostly used a combination of improvement methods. In addition, modelling software programs should more often be used, since they can take into account effects of different energy efficiency improvement methods on indoor air quality in different types of buildings and in different climates.

  • 202.
    Weerathunga, Lahiru
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik. Open University, Sri Lanka.
    ANALYSIS FOR AN ECONOMICALLY SUITABLE COAL TO PUTTALAM COAL POWER STATION TO RUN THE PLANT IN FULL LOAD CAPACITY2014Självständigt arbete på avancerad nivå (masterexamen), 80 poäng / 120 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Sri Lanka is an island at the Indian Ocean with 65234 km2 and it has a power demand of 2000 MW. The hydro power was the main power source before year 2000, after maximum usage of hydro power Sri Lanka installed fossil fuel power plant to achieve the demand. Then the electricity price gradually increased due to higher increment of fuel price. As the solution for this higher price of electricity the government has to go to new profitable power source the coal power. Finally year 2011 Puttalam coal power plant 300 MW x 1 was installed with the hope of providing the low cost reliable energy supply to Sri Lanka and it will be extended to 300MW x 3 plan in year 2015. Therefore the puttalam coal power plant is the key power plant to the Sri Lankan power generation and it is expected to have the maximum output (base load) to the Power demand of Sri Lanka.

    Sri Lanka is a tropical country and it has two different weather seasons as rainy season and dry season. The puttalam power plant situated at Kalpitiya peninsula and it has normally dry weather condition, Months of April, October November and December have heavy rain condition (Meteorological Department, Sri Lanka, 2012). The puttalam coal power plant may not achieve full load because of high moisture content at rainy season. So this Thesis carried out to find the capability to achieve the full load with available plant, plant capacity by using different coal qualities. Then find the economical benefits and effect on the environment with the recommended coal for different seasons and also design a storage plan to coal storage at existing coal yard.

    Based on the historical data and the Meteorological department rain fall data and by doing a technical analysis the recommended coal type was selected and the capability of plant equipment capacity to the recommended coal to achieve the full load was analyzed. Then the coal storage plan was designed according to annual requirement of the different recommended coal and economical benefit was analyzed by considering last year cost for generated power and the generation cost, if recommended coal is used for last year. Finally flue gas analysis was carried out for the recommended coal to find the effect on the environment.

    The recommended coal for rainy season is with the heating value of 6600 kcal/kg and for dry season it is 6300 kcal/kg. The capacities of main boiler and other plant equipments are capable for the recommended coal to achieve the full load of the plant. Then the design of the coal storage plan was given under figure 4.2 and table 4.1. It was calculated that a profit of 3.932 million US$ can be achieved by using the recommended  coal for the last year and also when compared with the changing price of oil and coal it will be more profitable for the future. Because the oil price increases very rapidly and the increase in coal price is very low compared to the oil price. Finally the SOx and NOx emissions from recommended coal were analyzed and it was within the environmental limits because of the high quality emission reduction plant equipments.

  • 203.
    Xie, Tian
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Multi-zone modeling of Thermal Comfort and Energy Consumption of a hospital ward: a summer case study2010Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Hospital is of interest when consider its especial function. Because of the obviously different between the normal residential buildings, the requirement of hospitals’ indoor climate strictly differs from other buildings.

    The author starts this report by briefly stating the building construction currently. Surrounded the topic of thermal comfort and energy consumption, many suggestion and options came out in this report to develop a better condition.

    Firstly, the introduction of the hospital buildings requires the background of the hospital object and the purpose to this report will be stated.

    Secondly, the simulation tool and how to use this tool simulate our real case are introduced.

    Then, the summer case is investigated by this tool after the model is proved to be validated.

    Finally, the improvement of establishing a better indoor environment is raised and the results of improvement and conclusion can be found. The final result will show the optimal solution that discovered by this study after compared different alternatives carefully.

  • 204.
    Yin, Shi
    et al.
    Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
    Li, Yuguo
    Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
    Sandberg, Mats
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Energisystem.
    Lam, Kitming
    Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China.
    The effect of building spacing on near-field temporal evolution of triple building plumes2017Ingår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 122, s. 35-49Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Building plume is important for ventilation and pollutants dispersion along and above buildings in an urban canopy layer. This study fundamentally explores the merging process and temporal penetration of triple uniformly distributed starting building plumes, with a focus of the spacing effect on near-field flow dynamics. Instantaneous velocity and vorticity distributions, penetrating velocities, and stream-wise penetrated heights are quantitatively examined using 2-D particle image velocimetry (PIV) measurements at spacing ratios S/W (building spacing/building width) of 0.2, 0.5, and 1.0. We identified a four-stage merging progress and captured three main spacing-induced merging features. A compact layout at S/W = 0.2 introduces a strong upward channel flow. The wall flows beside the channel tend to draw together first and the unstable channel flow determines the flow pattern transition. In contrast, wider layouts at S/W = 0.5 and 1.0 exhibit intensive downward flow. The wall flows tend to exhibit self-merging initially and the downstream natural swaying motion dominates the merged pattern variations. Merging effect and buoyancy force jointly determine the temporal penetrating velocities. Temporal series of maximum axial velocities above the middle source fits into a power law profile at S/W = 0.2 but a linear function of time at S/W = 0.5 and 1.0. The normalized penetrated heights at S/W = 1.0 are notably faster than in the other two cases before the normalized time is at 3.00 probably because the weaker entrainment and interaction with neighbors lead to less energy and momentum dissipation, quicker self-merging, and faster penetration.

  • 205.
    Zana, Tahsin
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik.
    Energimässig jämföelse med investeringskalkyl av två förskolor2011Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    This thesis includes an energy survey of the Herrgården pre-school, which has a modern heating- and ventilation system, and a comparison with Östers pre-school which has an older system. An energy survey of Östers pre-school has already been done by a group of three students and all the calculations and values have been collected from that survey. As of today, both pre-schools are heated thru district heating. It will be much easier to make smart and feasible energy-saving-measures by first conducting the energy survey.

    Herrgården pre-school in Gävle houses 81 children, therteen teachers, one cleaner and one cook. It was finished in the middle of 2009 and the staff has been very pleased with the in-door climate. In the energy balance added heat was calculated as district heat, solar radiation body heat and heat from lighting and other appliances. As lost heat- transmission, tap water heating, heating of ventilating air and excess ventilation was taken in to account.

    At Öster pre-school there are 66 children, twelve teachers and two economists. The pre-school was built in 1973. Gävlefastigheter which administrates both buildings are planning to change the ventilation system at Östers since it has been inferior and the staff has been experiencing bad in-door climate.

    The purpose of this thesis is to conduct a survey of how to economically reduce the energy consumption and to establish a good in-door climate like the Herrgården pre-school. The methods used have been to make a few visits on site to collect data.

    After finishing the survey it was shown that one could save 76,23 MWh/year if Öster has the same U-values as Herrgården for its´ roofs, floors walls and windows and a ventilation heat exchanger with 70% efficiency. However, none of these approximate calculations of installations at Östers pre-school turned out to be financially feasible.

     

  • 206.
    Ängskog, Per
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för elektroteknik, matematik och naturvetenskap, Elektronik. Department of Electromagnetic Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Bäckström, Mats
    Department of Electromagnetic Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Samuelsson, Carl
    Saab Aeronautics, Linköping, Sweden.
    Kangashaka Vallhagen, Bengt
    Saab Aeronautics, Linköping, Sweden.
    Shielding Effectiveness and HPM Vulnerability of Energy-Saving Windows and Window Panes2019Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 61, nr 3, s. 870-877Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we report results from shielding effectiveness measurements on energy-saving windows and individual, coated window panes of different generations, as well as results from high-power microwave irradiation on single panes. Shielding effectiveness was measured with two complementary methods: first, with near isotropic irradiation in nested reverberation chambers, and the other with irradiation at normal incidence in a semianechoic chamber. The measurements show that the construction of the energy conserving windows has a clear impact on how well they attenuate radio frequency signals. The more modern the window or pane, the higher is the shielding effectiveness. The high-power irradiation on coated panes showed that depending on the type of coating, hotspots can build up causing the coating to crack and, hence, deteriorate the shielding effectiveness. These results may serve as guidance when reviewing high-altitude electromagnetic pulse (EMP), high-power microwave, or intentional electromagnetic interference protection of critical infrastructures, and provide assistance in the work with reduction of compromising emanations.

2345 201 - 206 av 206
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