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  • 1051.
    Wangel, Josefin
    et al.
    Division of Environmental Strategies Analysis (fms), KTH Royal Institute of Technology, Stockholm, Sweden.
    Wallhagen, Marita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering. Division of Environmental Strategies Analysis (fms), KTH Royal Institute of Technology, Stockholm, Sweden.
    Malmqvist, Tove
    Division of Environmental Strategies Analysis (fms), KTH Royal Institute of Technology, Stockholm, Sweden.
    Finnveden, Göran
    Division of Environmental Strategies Analysis (fms), KTH Royal Institute of Technology, Stockholm, Sweden.
    Certification systems for sustainable neighbourhoods: what do they really certify?2016In: Environmental impact assessment review, ISSN 0195-9255, E-ISSN 1873-6432, Vol. 56, p. 200-213Article in journal (Refereed)
    Abstract [en]

    Certification systems for sustainable neighbourhoods started to emerge around a decade ago. This study analysed the content, structure, weighting and indicators of two established certification systems for sustainable urban development - BREEAM Communities and LEED for Neighborhood Development. Several limitations of these systems were identified: both have a bias for procedure and feature indicators over indicators that assess actual performance; performance demands are set according to a relative understanding of sustainable development; the focus is on internal sustainability, while upstream and downstream impacts of construction are disregarded; the number and distribution of mandatory issues do not cover essential sustainability aspects; and the disproportionately large number of non-mandatory issues makes benchmarking difficult and signals that sustainability aspects are exchangeable. Altogether, this means that an area can be certified without being sustainable. Moreover, the lack of continuous development of certification requirements in the systems means that they risk exerting a conservative effect on urban development, rather than pushing it forward.

  • 1052.
    Weerathunga, Lahiru
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering. Open University, Sri Lanka.
    ANALYSIS FOR AN ECONOMICALLY SUITABLE COAL TO PUTTALAM COAL POWER STATION TO RUN THE PLANT IN FULL LOAD CAPACITY2014Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    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.

  • 1053.
    wei, zheng
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    IMPROVEMENT OF BUILDING PERFORMANCE BY MULTIZONE MODELLING2012Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This paper is aiming to analyze the energy consumption of a building located in Satra, GAVLIE. Computer simulations of multizone airflow and thermal transport are performed in order to analyze the indoor climate and at the same time reduce the use of energy in the present building.

     

    At the same time, economic factors need to be considered based on energy-saving. Via use economic analysis tool to determine the feasibility of the energy-saving program in order to make sure the program getting recovery. With energy prices going up and increasing environmental awareness, designing an energy-efficient building is more important than ever.

  • 1054.
    Weinberger, Gottfried
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Amiri, Shahnaz
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Department of Management and Engineering, Division of Energy Systems, Linköping University, Linköping, Sweden.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Department of Management and Engineering, Division of Energy Systems, Linköping University, Linköping, Sweden.
    On the benefit of integration of a district heating system with industrial excess heat: an economic and environmental analysis2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 191, p. 454-468Article in journal (Refereed)
    Abstract [en]

    Energy-related cooperation using industrial excess heat (IEH) in district heating (DH) networks shows economic and environmental benefits. A rarely investigated approach is the energy cooperation which incorporates a jointly operated CHP plant also producing process steam for nearby industry. The present study aims to evaluate economic and environmental effects on the Hofors DH system with jointly operated CHP plant when the nearby steel mill extends the supply of recovered IEH. Various IEH supply opportunities with different capacities of hot water and steam were designed and compared with existing IEH utilization, plant heat and electricity production and DH system performance. The energy system model MODEST is used for cost-optimization. A parametric study is used to analyze influences of increasing IEH cost and fluctuating electricity prices. The results show advantages for the DH system to utilize IEH for deliveries of DH and process steam and the cogeneration of electricity. Economic and environmental benefits are decreased total system cost (-1.67 MEUR/a), less use of fuels and electricity, and reduced CO2 emissions with a maximal reachable amount of 28,200 ton/a when the use of biofuel is assumed as limited resource and the substituted marginal electricity production is based on coal condensing power plants. The results also show that industrial steam is a preferred heat supply source as long as the steam cost is below the alternative heat production cost, irrespective of the electricity price. While the cost-effective utilization of industrial hot water for DH is more sensitive and affected by a beneficial CHP production based on higher electricity price segments, it is also shown that utilization of continuously supplied industrial hot water is limited during seasons of low DH demand.

  • 1055.
    Weinberger, Gottfried
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Investigating influential techno-economic factors for combined heat and power production using optimization and metamodeling2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 232, p. 555-571Article in journal (Refereed)
    Abstract [en]

    This paper investigates the interaction of a wide range of electricity and fuel prices and technical factors of combined heat and power production in a district heating system. A linear programming-based optimization model with the objective to minimize system cost was used to study the energy systems in the cities of Gävle and Sandviken in Sweden. The comprehensive outcomes from optimization and parametric studies have been analyzed using a polynomial-based metamodel. System costs include variable costs for the production and revenues for sale of heat and electricity. The metamodel is used as an analytical and explanatory tool to interpret input-output relationships. Municipal district heating systems of Gävle and Sandviken in Sweden are studied as an interconnected regional system with improved and new combined heat and power plants. The results show that effects from electricity and fuel prices are important, but that variations in energy system cost may also be caused by many cross-factor interactions with technical factors. A comparative system performance analysis with defined cases and optimal factor setting shows a substantial increase in the electricity production, here by up to 650 GWh annually. The profitability of investing in a new plant depends highly on the considered investment risk and electricity and fuel market prices. CO2 emission savings by up to 466 kton annually can be accomplished if marginal electricity production from coal-condensing power plants is avoided and biofuel is released at the same time.

  • 1056.
    Widström, Torun
    et al.
    Department of Civil and Architectural Engineering, The Royal Institute of Technology, Stockholm, Sweden.
    Mattsson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Building science - installation technology.
    Multifunctional whole building simulation as a method in assessing retrofitting strategies in historical buildings2011In: Proceedings of Building Simulation 2011: 12th Conference of International Building Performance Simulation Association, Sydney, 14-16 November, 2011, p. 2943-2949Conference paper (Refereed)
    Abstract [en]

    The design of retrofitting strategies for historical buildings involves various challenges. The aim is often not only to save energy while providing acceptable indoor conditions for its users, but also to preserve the building and potential cultural artifacts, making it a multi-criteria issue, with multiple demands on the simulation tools and methods. This paper describes one way to fulfill on these demands through a serial, stepwise simulation process and a special tool, designed for that process. A case study, performed with the use of the method and tool, is presented. The results show that the method is workable and provides good agreement between simulated results and measured data.

  • 1057.
    Widström, Torun
    et al.
    The Royal Institute of Technology, Stockholm, Sweden.
    Mattsson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Building science - installation technology.
    Simulation of the energy performance of historic buildings.2011In: EEHB 2011: Conference on Energy Efficiency in Historic Buildings. / [ed] Tor Broström & Lisa Nilsen, 2011Conference paper (Refereed)
    Abstract [en]

    In historical buildings, to an even greater extent than in modern buildings, the energy performance is connected to other aspects, such as moisture performance and damage risks. Here building simulation is of value, but it also faces some challenges in the form of complexity, flexibility and stability that need to be overcome in order to render useful results. This paper suggests a new, serial approach to the simulation process and presents a new simulation tool that makes it possible.

  • 1058.
    Widström, Torun
    et al.
    The Royal Institute of Technology, Stockholm, Sweden.
    Mattsson, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Building science - installation technology.
    Whole building simulation and damage risk assessment in historical buildings2011In: Energy Management in Cultural Heritage / [ed] Vlasta Zanki, UNDP Croatia , 2011Conference paper (Refereed)
    Abstract [en]

    When simulating historical buildings, available tools tend to be intended for simulations of either of two kinds: whole building simulations of energy-/moisture performance, from which we can determine general conditions that may give an indication of potential damage risks, though unspecific, or detailed simulations that look into what takes place at specific points/materials, which provides us with knowledge about the specifics but without much context. Both are efficient scientific methods, but when dealing with reality we need both perspectives simultaneously. This paper describes multi-criteria simulations that take this into account, using a new tool integrating display of specific moisture-connected risk-factors into whole building simulations, providing a coherent basis for decision-making when retro-fitting, and compares the results to case-study measurements.

  • 1059.
    Wigö, Hans
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Building science - installation technology.
    Effects of intermittent air velocity on thermal and draught perception: A field study in a school environment2013In: The International Journal of Ventilation, ISSN 1473-3315, E-ISSN 2044-4044, Vol. 12, no 3, p. 249-255Article in journal (Refereed)
    Abstract [en]

    Air movement in an indoor space may be experienced in very different ways. For persons feeling cool, air movement tends to be perceived as draught, whilst when feeling warm air movement may provide a desired cooling effect. In the transition zone it therefore seems difficult to use constant air velocity as a tool for cooling without creating draught problems. One possible way to use air movement as a method to improve thermal comfort, without resultant draught problems, could be to use intermittent air velocity instead of constant velocity. This new cooling method was implemented in a high school in Sweden and evaluated during spring (April) and autumn (September). The present paper reports results from two field experiments where subjects were exposed to velocity variations. The analysis shows significant effects of velocity condition on thermal comfort and air quality. In summary, people exposed to velocity variation perceived the air as cooler and fresher compared with those exposed to constant low velocity and very few classified the air movement as draught. A further conclusion is that even the pupils who were exposed to velocity variation wanted slightly more air movement.

  • 1060.
    Wigö, Hans
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Building science - installation technology.
    Lahtimo, Marjo
    Colliding isothermal ceiling jets as a method to generate velocity variations in the occupied zone2011In: Proc. Roomvent 2011: 12th International conference on air distribution in rooms. Trondheim, Norway., 2011Conference paper (Refereed)
  • 1061.
    Wijesinghe, Nadeera
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering. Royal Institute of Technology, Sweden.
    Rural Electrification - Sri Lanka: A Case study & Scenario Analysis2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    “Rural electrification” is a key element in the global energy development agenda. While being a developing country, Sri Lanka is enroot to achieve 100% of electrification at present. After the civil war ended in 2009 which lasted for more than 25 years, there has been much focus to fulfill the energy needs of the country. But the studies carried out to assess the impact of electrification are very much limited. This study focuses on meeting the gap of carrying out a scenario analysis of rural electrification and assessing the socio economic impact of electrification. The major focus has been given to see how energy system of a newly electrified village will vary over time. The research intends to identify how far the strategies used to implement a policy is realistic in the real world. Also the research extends to apply the proposed strategies to the energy model and analyze the behavior of the model. During the study a survey was carried out in a rural village in southern part of Sri Lanka and the data obtained were used to model the energy system of the village using a software called - LEAP (Long Range Energy Alternative Planning System). The energy system is simulated under different scenarios to analyze if certain strategies in the policy have been implemented in the village. Two scenarios were energy efficient lighting and energy efficient cooking stoves. A total energy balance has been carried out for the target sample with an analysis of global warming potential of the activities of the target family. The total energy consumption variation with the electrification and the percentage of energy consumed as electricity over time has been analyzed. Further the socio economic impacts of electrification have been studied. The impact of agricultural usage and economic productivity with electricity has been studied. The qualitative measures like attitude changes, modernization & technology adaptation were addressed to the extent possible.

  • 1062.
    Wiklander, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energikartläggning av polishuset i Gävle: Åtgärdsförslag för ett minskat energibehov i fastigheten Gävle Söder 17:102014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The objective of this work was to introduce measures to reduce energy and water demand at Gävle Söder 17:10. To succeed, this energy audit has been made. The work is based on collected statistics from the property owner Norrporten, measurements, literature review and through consultation with experts in the field. Two models, one for each building, have been created in the simulation program BV2 to estimate the potential of energy measures based on the collected information. The models in BV2 have been verified against the statistics of the energy consumption.With the help of calculations and simulations, seven cost-effective measures have been identified. This involves replacement of a ventilation unit, installation of low-flow nozzles and better management of the mechanical chiller. Overall, the measures are expected to reduce heating requirements by 223 MWh/year (17%) and reduce electricity demand by 66 MWh / year (5%). Additionally, the water demand can decrease by 609 m3 (12%). The total costs are estimated to decrease by 143,000 SEK per year, excluding VAT, with a payback period for the investment of 3.9 years. The proposed measures also contribute to reducing emissions by 4.16 tons CO2/year or 8.61 tons CO2/year, depending on whether emissions for electricity is based on the Swedish or Nordic electricity mix.

  • 1063.
    Winding, Sebastian
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    BAJT: Digital teknik i hemmiljö2014Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
  • 1064.
    Winsjansen, Frida
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Utredning av energibesparingspotential och lönsamhet hos kompressorsystem med värmeåtervinning: För integrering i industriellt uppvärmningssystem2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In order to meet the growing demand for energy in the future, while contributing to a long-term sustainable energy supply, resource and energy efficiency measures are required within several sectors. In 2016 the industry sector accounted for more than 50 percent of the global power demand. The use of existing resources, such as waste heat from compressed air production, is a possible efficiency measure. 

    Behind this thesis work is a request from the Sandvik AB Group to estimate savings potential and reinvestment costs in one of the industry's compressor centers, Götvalsverket. The reinvestment refers to two new compressors whose waste heat is integrated into the industry's existing district heating system and allows for reduced resource and energy costs as well as a reduction of CO2-emissions. 

    This work aims to investigate different compressor alternatives from an economic- and environmental perspective. This is done using collected data, a sensitivity analysis and profitability calculations with an attached LCC-analysis. The aim is to answer various questions regarding total investment cost, energy and resource saving as well as emission reduction.

    Two cases in production are investigated. The first according to the existing operation hours in Götvalsverket and the second case with an optimized operating time for the compressor units. 

    A literature review has also been conducted where several studies show that compressed air is an expensive alternative to energy production and that implementation of efficiency measures, including waste heat recovery, can be well-founded investments. Other benefits can also be linked to energy efficiency, such as improved production and an improved work environment for employees. 

    The result of the work showed that one alternative in particular stood out from the other compressor solutions, both from an economic and environmental point of view. This option did not offer the cheapest investment but the amount of recovered waste heat was much larger than for the other alternatives and therefore, energy savings reduced the payback period drastically. 

    The utilizing of existing resources such as waste heat, together with the industry sector’s reduced energy consumption, is considered a necessity in order to ensure the well-being of people, animals and nature in the future.

  • 1065.
    Wright, Sandra A. I.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Biology. University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Patulin in food2015In: Current Opinion in Food Science, ISSN 2214-7993, E-ISSN 2214-8000, Vol. 5, p. 105-109Article, review/survey (Refereed)
    Abstract [en]

    Patulin is produced by species of Penicillium, Aspergillus and Byssochlamys. It is a mycotoxin that primarily contaminates pome fruit products, but is being reported from other fruit and foods, for example shellfish and cheese. New findings reveal that patulin binds to the bases of DNA, in addition to its well-established ability to conjugate sulfhydryl groups. Novel cellular targets are also being uncovered. In the EU, patulin levels in apple products are now mostly below specified limits. Biocontrol agents either prevent infection by mycotoxigenic fungi or lower patulin levels. More knowledge about critical control points, the role of patulin in plant disease, and the environmental cues that stimulate patulin production will enable the tailoring of effective, future control measures.

  • 1066.
    Wright, Sandra A. I.
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Rönnander, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Novel biodegradation of vanillin by a woodinhabiting isolate of Cystobasidium sp.2018In: Book of abstracts: International Specialized Symposium on Yeasts ISSY 34, 2018, p. 114-114Conference paper (Refereed)
    Abstract [en]

    Cystobasidium species are mostly found in temperate or cold environments. They have been isolated from a wide range of habitats: plants, soils, rocks, aquatic environments and indoor dust. The genus Cystobasidium mainly consists of species of red yeasts in the Rhodotorula minuta clade. These basidiomycetous yeast species are commonly found in temperate to cold regions. In the present study, two strains of Cystobasidium sp. were isolated from decaying wood of housing on the Faroe Islands, where the average yearly temperature ranges from 2°C to 13°C. The sequences of the two strains had two identical gaps within the ITS1ހ5.8SހITS2 region and a second gap within the D1/D2 LSU unit, when aligned to those of C. laryngis CBS 2221, their closest match. The isolates were designated as Cystobasidium sp. Both isolates converted vanillin into vanillyl alcohol in the presence of oxygen. The biotransformation of vanillin into vanillyl alcohol has been documented for only a few species of fungi, but to our knowledge, it has not previously been reported for any basidiomycetous yeast species. Rhodotorula rubra, a distantly related basidiomycetous yeast converts vanillin into vanillic acid. In the present study, the two isolates of Cystobasidium sp. did not produce any trace of vanillic acid, as determined by LC-MS, 1HހNMR and GC. Oxidizing vanillin into vanillic acid should be preferred by the fungi, since it results in more chemical energy, as compared to reducing it to vanillyl alcohol. The fungus may choose this pathway to escape the toxicity of both vanillin and vanillic acid. Vanillin has antimicrobial activity, and vanillic acid is more toxic than vanillyl alcohol. Vanillin is a constituent of the lignin molecule. Cystobasidium species are commonly found in the phyllosphere. Their ability to utilize plant chemicals should render them successful competitors on plants and wood.

  • 1067.
    Xiao, Naiyuan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Comfort temperature analysis in a historical stone church2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis a church named Hamrånge, located North of the town Gävle in Sweden, has been studied. In this church thermal comfort is a problem that need to be considered. There is poor insulation and air leakage in the building envelope. And appearance doesn't allow to add any additional insulation, becauce people want to keep its original appearance. In cold weather the church is heated by bench heaters and radiators through direct electicity. 

  • 1068.
    Xiao, Naiyuan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energy-efficiency building envelope technologies2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In recent years, the excessive emission of greenhouse gas CO2, it causing globalwarming, already poses a serious threat to human survival. The problem catches theattention all over the world, and promoting the development of building energyefficiency. In order to the sustainable development of human beings, in 1992 theUnited Nations framework convention on climate change (UFCCC) organizationpublished the Kyoto protocol. In the Kyoto protocol, the European countriescommitted that during 2008 and 2012 they would reduce the amount of greenhouseemissions to 8% compare to 1990.[2] Building envelope technologies can helphouseholder reduce the energy consumption use in the building. Building envelopetechnologies used in the project Brogåden – Alingsås which save the energyconsumption from 204 kWh/ m2a to 95 kWh/ m2a in Sweden. While the cost just838SEK/m² or 8% of the total building costs. In China the envelope technologies usedin the project student apartment in Shandong building university save the energyconsumption about 72% compare with the old student apartments.

  • 1069.
    Xie, Tian
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Multi-zone modeling of Thermal Comfort and Energy Consumption of a hospital ward: a summer case study2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    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.

  • 1070.
    Yang, Bin
    et al.
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Olofsson, Thomas
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Nair, Gireesh
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Kabanshi, Alan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Outdoor thermal comfort under subarctic climate of north Sweden – A pilot study in Umeå2017In: Sustainable cities and society, ISSN 2210-6707, Vol. 28, p. 387-397Article in journal (Refereed)
    Abstract [en]

    Outdoor microclimate is important to determine the quality of outdoor spaces. Swedish people cherish summer period and prefer more outdoor activities in summer because of long winter with harsh outdoor environments. People in urban areas use parks for recreation and outdoor activities frequently in summer. Under subarctic climate, limited studies have been performed to explore the effect of microclimate environments on usage of outdoor spaces such as parks. The study explored the relationship of microclimate environments, park use and human behavioral patterns in urban area of Umeå, Sweden, which is under subarctic climate. Observations of naturally occurring behavior were recorded. Structured interviews, based on specially designed questionnaires, were performed during July to August in 2015. Measurements of objective parameters for microclimate environments, including air dry bulb temperature, relative humidity, wind speed, solar radiation and globe temperature, were performed. Human subjective responses from the questionnaire survey were compared with objectively measured results. 49% of local persons still prefer higher solar radiation even under “slightly warm” Thermal Sensation Vote (TSV), which reflects their high expectation to solar radiation. Local persons in Umeå, who expose themselves to a wider climate, are more adapted to subarctic climate than non-local persons.

  • 1071.
    Yang, Fan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Wang, Dongcan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Challenges and countermeasures of China's energy security2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To ensure energy security, the first to know what is energy, and second, what are the factors of non-security, means that the challenge of energy security. Finally, puts forward some policy or in the case of a reasonable method to solve it according to these problems. At present, energy security is facing two challenges of structural crisis and crisis management system. Concretely, main problems in that security are analyzed, which are considered to affect China and mostly embody in such four big areas as the great pressure in energy supply, the scarcity of relative energy resources, foreign oil dependence is too large, crisis management systems of energy security, the shortage of green energy. Furthermore the counter measures concerned are proposed, including saving energy and increasing the energy utilization rate, to establish strategic energy reserves, strengthening environmental protection and adjusting the primary energy structure.

    China's rapid economic growth lead to sharp increase in oil imports. Due to China relies on a single chokepoint, the Malacca Strait, which has caused a high degree of concern about the safety of its energy. Nearly three-quarters of its oil imports flowing through the Strait. In view of its strategic importance to China and China’s little sway on the waterway, this view is mainly focused on China’s energy demand and supply in two aspects of concern.

    The paper analysis of whether the current energy structure is appropriate and sustainable. Because the energy security is facing China's energy is more and more dependent on imported fuel and the need to convert energy to meet the demand of modern society and the rapid growth of the requirements of the economic challenges. Concludes that the China's new policy should focus on energy efficiency, energy saving, renewable energy and turned to the main energy source of natural gas.

  • 1072.
    Yang, Frank
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Goldman, Mattias
    Forum for reforms, entrepreneurship and sustainability (Fores), Stockholm, Sweden.
    Lagercrantz, Jakob
    The 2030 secretariat, Stockholm, Sweden.
    Sustainable Mobility the Chinese Way: Opportunities for European cooperation and inspiration2018 (ed. 1)Book (Refereed)
    Abstract [en]

    The book introduces China's endeavours in sustainable mobility to combat climate change and ease air pollution, including electric vehicles, high-speed rail, shared bikes and cars, etc. Suggestions are given on how Europe and China can learn from each other for a more sustainable world.

  • 1073.
    Yang, Yuchen
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Liang, Jieqiong
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energy Audit for the Gävle University Library2013Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
  • 1074.
    Yao, Li
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    ENERGY AUDIT OF HIG STUDENT HOSTEL2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nowadays in the world, energy usage effectiveness has always been an issue which blocks people’s development. How to effectively use the energy is becoming more and more important. Energy audit can appraise the energy usage condition of a building, and come up with improvement advices through systematic calculation and analysis the existing problems and reasons for energy wastes, in order to bring the object of effective usage of energy into reality.

    HiG student hostel 23 is situated in Gävle, a coastal city in the east of Sweden. There are three floors in Hostel 23, the first and second floor have 18 single rooms, 4 double rooms and 2 communal kitchens and the third floor is storeroom. The aim of this thesis is to explore indoor climate and energy use for this student hostel and find out the reason of the low temperature inside the room, seeking some ways to improve the thermal comfort inside the building during winter conditions.

    First, collect date from every part in energy balance by measurement and interview with administrator, then calculate and analyze the data. At last, the whole energy balance can be estimated. Through analyzing the whole energy balance, the suggestion is to change the window type and design a new ventilation system operating plan. Through the optimization, energy loss is reduced, and about 10% of the energy is preserved. Besides this, the building infiltration loss is too high through this energy audit; it states there still exists some problems. If these problems can be solved, it will be helpful to keep a good thermal comfort inside the building.

  • 1075.
    Yao, Li
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Liao, Xinyan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energy Audit of HiG Examination Building2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nowadays, energy is becoming more and more important. With the development of society, the demand of energy is also increasing correspondingly. There is 22% of the total energy which is used in building part. A more effective and sustainable energy system becomes necessary due to increasing energy prices and demand. The aim of this thesis is to make an energy survey of this building, evaluating different sources of energy supply and losses in this building. By evaluating, a better thermal comfort is expectedly achieved when having examinations, and a possible saving method is also expected in order to reduce the cost of this system.

     In this project, the building is located in University of Gävle which is surveyed. It has 2 floors. The first floor is underground as a basement. An examination room is included in the second floor. There are a space heating system and heating recovery system ventilation in this examination building.

    At first step of analysis, the data of construction, ventilation, district heating and hot tap water were arranged by Mr. Magnus. Secondly, an energy balance had been done, and it helped to make energy input and output more clearly. In energy supply part, the solar radiation is 22.4MWh, the internal heat from people is 1.95MWh, the internal heat from equipment is 5.63MWh and district heating is 184MWh. In energy losses part, the transmission loss is 165MWh, the mechanical ventilation loss is 38.3MWh, the infiltration loss is 8.38MWh and the hot tap water is 2.09MWh. Thirdly, results of calculations were analyzed. At last, the optimization methods were given to save energy. The optimization methods were changing type of windows and improving indoor temperature which influenced the transmission loss part. Another method was reducing operating time of the ventilation system.

    Through these optimizing methods, the total energy use is reduced from 214MWh to 179MWh, and district heating is reduced from 184MWh to 149MWh. District heating of this building is supplied by Gävle Energi company, which is able to save 20% cost by these optimizing methods. According to the investment analysis, 19thousand SEK energy is saved per annum.

  • 1076.
    Yekkalam Lary, Nazanin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energy Balance and Temperature Rise Study in Cutting Station at Sandvik AB2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The project is a detail study of Energy Balance in cutting line station in Sandvik Mining and construction group.

    The aim of the project is reducing temperature and making a temperature balance inside the cutting line. During the recent years, many changes occur in production line. Existing cooling system cannot supply cutting area temperature below the desired level. Electrical Cables are melting due to high inside temperature. We attempted to study the old drawings and existing cooling system in cutting station to find out solutions to optimize and rebuild the old system. First part of study contains checking of preliminary air and water cooling system drawings. In the second part we looked at the operating cooling system by measuring different available working conditions such as inside temperature, air velocity and cooling water flow rate with different measuring equipment. The study integrate hot and cold stream (cooling air and water system) at different temperature level and in different times through production or non-production hours. Finally results and solutions can give valuable guidance for enterprises on how cooling systems should be expanded, what sizes should the new equipment have, where should the heat recovery exchangers be built, what new pipelines are needed, etc. To find more accurate results, we tried to do all measurements simultaneously, but due to difficult working condition it was not possible to have all input data at the same time. According to the primary data energy consumption during different times and Peak consumption amounts were calculated. Results consider the differences in cooling system effects inside the cutting line and the system which generates more cooling load and needed more improvements.  The summer and winter conditions are different inside the work area. The simultaneous assurance of ventilation, energy reduction and occupant health remains a design challenge. Working area is a unman area; therefore environmental impact are not considered in this research.

  • 1077.
    Yi, Xueying
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Solla, Ivette
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Analyzing the Challenges and potential Opportunities for a Swedish Newly Established Firm when entering the Chinese Food Market: a marketing study for BIM in Zhuhai City2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    China has become one of the largest markets for business investments. A great number of foreign companies have showed interest in the Chinese market; even more when they seen how other companies have succeeded in the crossover. However, not everyone has been lucky enough to be successful in the Chinese market; this is especially true for small firms. Small companies have faced big troubles when entering the Chinese market; specifically those who decided to go international after a mere few years. In this study, we will show the challenges and potential opportunities for Swedish newly established firm when entering Chinese market. The company chosen was a Swedish food company called BIM, which also promotes healthy life styles.

       

    The authors begins the paper by briefly introducing the BIM company, background of this study, and some definitions, such as the Chinese concept of networking or Guanxi, the difference that exists between Swedish and Chinese managerial style and negotiating style and how can all of these issues can make a difference in succeeding in China. Next, the authors introduce the theoretical model which is a combination of opportunities; such as: costs of labour, market size and availability of resources; and barriers such as: networking, bureaucracy, culture, managerial and negotiating style. 

     

    Finally, the results show that new established companies that acknowledge the importance of a well establish network will have a bigger chance to succeed while doing business in China. A marketing study and interviews for the company BIM are shown in the appendix to assess opportunities and challenges before and after entering the Chinese market.

  • 1078.
    Yifan, Wang
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Yizhang, Huang
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Urban Wind and Thermal Environment Simulation - A Case Study of Gävle, Sweden2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As urbanization and industrialization progressed during the last decades, Urban Heat Island (UHI) has become a major environmental issue to many cities around the world. The effect of UHI differs from area to area due to varying urban scale, population density, construction of urban surface layer, the level of industrialization and type of climate. Researchers have made great efforts in investigating various approaches to Urban Heat Island studies. Monitoring technologies have been widely used in this field, especially Geographic Information System (GIS) and remote sensing technology. Computational Fluid Dynamics (CFD) simulations are also actively applied in wind engineering, which can provide details of air flow over urban areas. The combined application of these technologies can provide the monitoring and simulation of urban wind corridor and thermal environment that can produce relevant information at a lesser time.A research using GIS, remote sensing technology and CFD simulation was done in this project to obtain a holistic view of the urban thermal environment and wind flow for Gävle City. With GIS and remote sensing the thermal image of the city was presented. The temperature data, which were collected from MODIS satellite were transferred and processed by ArcGIS and Global Mapper. The wind flow above the city was simulated through constructing geometric and mathematical model with OpenFOAM. The outcomes of the modeling and simulation identified that the temperature in the city center could possibly reach 35℃ during summers, which can cause the Urban Heat Island to form. Ventilation was also poorer in the city centre, and neither the river nor the green area in the southwest could help ventilate the city. The study result also suggested that certain sites in the city had relatively high wind flow for urban wind turbines to work.This study had used method of Urban Heat Island study with remote sensing and CFD technologies. The model produced from simulation could also be used to further study Gävle city's thermal and wind environment to produce more accurate results.

  • 1079.
    Yin, S.
    et al.
    Department of Mechanical Engineering, University of Hong Kong.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Li, Y.
    Department of Mechanical Engineering, University of Hong Kong.
    Water tank investigation of single and multiple buoyant plumes from squared blocks in calm environment2014In: Indoor Air 2014 - 13th International Conference on Indoor Air Quality and Climate, 2014, p. 295-297Conference paper (Refereed)
  • 1080.
    Yin, Shi
    et al.
    Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China.
    Li, Yuguo
    Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China.
    Fan, Yifan
    Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Experimental investigation of near-field stream-wise flow development and spatial structure in triple buoyant plumes2019In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 149, p. 79-89Article in journal (Refereed)
    Abstract [en]

    This paper presents a systematic experimental study on stream-wise flow development and spatial structure of triple buoyant plumes. Two-dimensional Particle Image Velocimetry (2-D PIV) is employed to resolve velocity fields. Stream-wise axial velocity profiles, flow structure, flow region parameters, and self-similarity properties are analyzed at different configurations that are characterized by spacing ratios S/W (source spacing S divided by source width W). From velocity fields and axial velocity profiles, a similar stream-wise developing trend is identified in different source configurations. When near-field plumes travel downstream, axial velocities increase rapidly, off-center velocity peaks get merged with the central peak, and the number of velocity peaks reduces with the downstream distance. A compact source layout, comparing with the wide one, could enhance the near-field plumes interaction and promote the plumes deflection significantly. Fundamentally, the stream-wise spatial structure of the triple plumes initially consists of a converging region, followed by a merging region, and finally a combined region. By examining the averaged velocity fields, flow recirculation with negative axial velocities is found to scarcely exist in the converging region. Merging level Zm and quasi-combined level Zqc are analyzed quantitatively and statistically. Within the studied S/W range, the normalized Zm shows a linear increase with S/W in the formula of Zm/H=2.007(S/W)+1.173 and the normalized Zqc gives a power law increase with S/W in the formula of Zqc/H=6.035(S/W)0.4959. In addition, triple plumes are found to establish self-similarity approximately at Z = 3H with S/W of 0.2 and at Z = 4.5H with S/W of 0.5.

  • 1081.
    Yin, Shi
    et al.
    Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong.
    Li, Yuguo
    Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong.
    Fan, Yifan
    Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Unsteady large-scale flow patterns and dynamic vortex movement in near-field triple buoyant plumes2018In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 142, p. 288-300Article in journal (Refereed)
    Abstract [en]

    Unsteady flow patterns of interacting buoyant plumes are important for buoyant ventilation and particularly influence pollutant and heat transports in indoor and outdoor environments. This study reveals fundamental large-scale flow patterns in triple building plumes, investigates vortex moving trends during the pattern transition processes, and explores possible mechanisms of pattern diversity by two-dimensional (2-D) Particle Image Velocimetry (PIV). Total five tests are studied, including three different heat strengths Q (180, 90, and 30 W) and three source layouts characterized by the ratios of source spacing S to source width W (0.2, 0.5, and 1.0). Streamline distributions and axial velocity profiles clearly reveal three fundamental global flow patterns: a right-slanting asymmetrical flow pattern, a left-slanting asymmetrical flow pattern, and an axisymmetric flow pattern. Correspondingly, it indicates four basic transition processes, i.e., right-to-center, left-to-center, center-to-right, and center-to-left transitions (“center” represents the axisymmetric pattern). A novel vortex tracking method, based on lambda-2 (λ2) criterion and principles of the PIV technique, is developed and successfully applied to qualitatively track the vortex moving trends during the transition processes. The regular vortex moving trends are found to be reasonably consistent with the global pattern transition trends. The flow pattern diversity is speculated to be mainly driven by unstable heat source wall flows and downstream swaying motions in this study. These critical unstable motions are considered to probably relate to unstable lateral entrainment and vortex interaction, particularly beside the central plume. Consistently, the regular vortex moving trends are usually observed in and around the central plume.

  • 1082.
    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
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    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 plumes2017In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 122, p. 35-49Article in journal (Refereed)
    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.

  • 1083.
    Yin, Shi
    et al.
    Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Lam, Kit-Ming
    Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region.
    Li, Yuguo
    Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region.
    Near-field merging and penetration of triple starting plumes from volumetric heat sources in a calm environment2017In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 115, no Part B, p. 1321-1333Article in journal (Refereed)
    Abstract [en]

    This paper investigates the buoyancy effect on near-field evolution of triple equal starting thermal plumes from volumetric heat sources, with a focus on merging process, velocity evolution, and stream-wise penetration. Instantaneous velocity fields and corresponding vorticity distribution, temporal evolution of centerline axial velocities, temporal penetrating rates and heights are examined by 2-D particle image velocimetry (PIV) at three different source heat strengths of 180 W, 90 W, and 30 W. A four-stage merging process is demonstrated to be independent of heat strength. Normalized starting and terminating times of each developing stage are also unified regardless of the heat strength, i.e., t/t∗ = 1.7–2.5 for stage i (relatively isolated development), t/t∗ = 2.5–3.3 for stage ii (bending wall flows), t/t∗ = 3.3–3.9 for stage iii (development after a self-merged state), and t/t∗ > 3.9 for stage iv (evolution with global merging). The axial velocity at a specific centerline point usually involves three distinct developing periods: a “centerline-silent” period ending at a normalized transportation time tt_n when heat is just transported to the measuring points, a fast rising period, and a fluctuating period starting at a normalized endurance time te_n. The buoyancy-independent tt_n is approximately 1.5, 2.2, 3.0, and 3.2 at a normalized downstream distance of 1.5, 2.5, 3.5, and 4.5, respectively. The time te_n, independent of buoyancy and axial height, is about 3.6 for all measuring points in this study. The maximum axial velocity above the middle heat source exhibits three linearly developing periods with different acceleration rates successively: a quicker rate as the wall flow develops, a slower rate due to enhanced lateral interaction, and the fastest rate as the global merging happens. In different periods, the proportional coefficients of linear fitted functions vary from 0.48 to 2.98. The downstream distance where axial velocity is maximum shows similar power-law increasing during t/t∗ = 1.5–3.2 at Q = 180 and 90 W, but exhibits significant fluctuations at Q = 30 W. Normalized overall penetration based on global velocity fields is notably faster and higher at the lowest buoyancy (Q = 30 W) than that at the higher buoyancy (Q = 180 and 90 W), probably due to the weaker lateral interaction and turbulent mixing together with the more dedicated vertical rise at Q = 30 W.

  • 1084.
    Ying, Song
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Energy analysis for a snow-free surface: A technical analysis of the benefits of insulation under the heating pipes2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Snow-free surfaces is needed for parking place, platform, and playground and even in city center square. With energy prices rising, energy saving is becoming a hot topic. Meanwhile environmental problems are becoming more and more serious, thus, the ways to saving energy is becoming an eye-catcher. So burring heating pipes underground has been a popular way to get ice-free surfaces. Using heating pipes for melting snow is much more efficient and more benefit for the environment comparing with using other methods.

     

    In this project, an energy analysis of a football pitch with an area of 5000 m2 is carried out under a series of conditions between insulated and uninsulated construction. All calculations are done with the so-called finite element method (FEM), in the COMSOL. COMSOL is used for simulating and calculating the energy use with outdoor temperatures of -5 ºC and -10 ºC. Top layer materials concrete, grass and stone are also discussed. The ability of XPS and EPS insulation material is compared and noted. The models are divided into two parts, one is with snowfall and the other is without snowfall.

     

    The results in the report shows that adding insulation under the heating pipe has significant energy saving potential. The surface with concrete layer has the best insulated ability, which can prevent more heat losses. The EPS insulated construction has a better performance in keeping more heat in the soil. 

  • 1085.
    Yoo, Alexander
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Industrial design.
    Studie om produktutveckling i praktiken2018Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [sv]

    I detta arbete har jag utforskat vissa moment berörande produktutveckling genom praktiskt utförande. Jag har fokuserat på tillverkning, då både samarbete och kommunikation är för mig (studerande) outforskade faktorer som påverkar ett produktutvecklingsprojekt. Detta är förhoppningsvis av intresse för andra studenter då det är viktigt att kunna hantera och förstå hur kommunikation och samarbete kan påverka. Det framstår att erfarenhet och kunskap berörande detta var en brist hos designstudenter. I detta arbete har jag utforskat olika tillverkningsmöjligheter utifrån tillgänglighet och kostnader. Via kontakt och samarbete med olika industrier och hantverkare har jag utvecklat olika idéer som slutligen har resulterat i ett produktkoncept. Fokus i detta arbete ligger inte på det kreativa arbetet som berör idégenerering, utan på det som faktiskt händer när produkter skall bli till på riktigt (utföras i praktiken). Tillverkningskostnader har begränsats av en utsatt prisklass utmärkt efter en marknadsanalys. Jag har utgått från att utveckla ett produktkoncept för ett cykelmontage i hemmet. Detta är en inredningsdetalj som är avsedd att ge cykeln en dedikerad plats i hemmet. Liknande produkter finns redan på marknaden, även företag som enbart fokuserar på att göra ”cykelmöbler” finns. I början av projektet försökte jag hitta medel för att tillverka ett cykelmontage som jag sen tidigare formgivit. Jag insåg snabbt att det var för dyrt att tillverka då konceptet fick möta verkliga krav berörande tillverkningskostnader. Jag fick under projektet nysta in en kompakt designprocess som inte tillfullo framstår i denna rapport. Jag har istället fokuserat på det som rapporten var avsedd för, att utforskat vissa moment berörande produktutveckling genom praktiskt utförande. Detta arbete har gett mig insikter berörande samarbete, kommunikation och sekretess. Jag hoppas att detta är intressant läsning framförallt för dig som aldrig har tagit steget som kommer efter konceptet och själva idén av en produkt.

  • 1086.
    Yuting, Wang
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energy-efficient industrial dryers of berries2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Saving energy is considered about by much more people nowadays. The energy use of industrial drying occupies a large part of total energy usage. Not only the governments, but also the industry owners are trying to find ways to cut down the usage of energy. The aim of this work is to find suitable technologies for industrial drying of berries which can be energy-efficient at the same time. More specifically, to find suitable dryers for drying aronia berry in Sweden. The research is based on secondary data collected by literature review. Good options for other circumstances like fluidized bed drying, freeze drying and solar drying were not discussed in detail. After the study, a continuous hot air dryer with explosion puffing system and heat pumping system seems to be the best solution for drying aronia berry in Sweden. It is easy to be controlled, cost acceptable (both capital and operational costs), environmental friendly and has high drying rate and high product quality. The extra means for improve drying process such as combined with dielectric or conductive dryer, adding pre-treatment such as osmotic drying were also discussed. Combined dryers can reduce the drying time and osmotic drying can cut the operation cost. Careful experiments shall be done before large amount of investment due to the complexity of dehydration.

  • 1087.
    Zabala, Leizuri
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Fusion energy: Critical analysis of the status and future prospects2018Student paper second term, 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The need to make maximum use of renewable resources to the detriment of fossil fuels to achieve environmental goals with an increasing energy demand is driving research into the development of technologies to obtain energy from sources that are not currently being exploited, one of them being fusion energy. The aim of this report is to provide a general overview of fusion and to provide a critical opinion on whether fusion will become a commercial energy source in the future, and if so when. The followed methodology has been a literature review complemented by an interview to B Henric M Bergsåker, teacher and researcher at the KTH on fusion plasma physics and information person for the Swedish fusion research.In the results section the fusion physics and different technological approaches have been presented. Among the studied different projects, the ITER Tokamak magnetic reactor has been selected as the most promising of these projects, as a product of international collaboration, and it has been analyzed in more detail. The obtained results have been that fusion can be an inexhaustible, environmentally friendly and safe energy source. The first-generation fusion commercial reactors are expected to be part of the energy mix before 2100.

  • 1088.
    Zabala Urrutia, Laura
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Measurements and simulations of the performance of the PV systems at the University of Gävle2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the following years, the countries will have to face an increase in the energy demand. So far, the fossil fuels have been the main source to meet the energy demand, but they involve serious problems: they contribute to the climate change with high emissions of greenhouse gases, there is an uneven distribution of these resources and their reserves are finite. The renewable energies are the most reliable alternative, with a very low environmental impact in comparison. Among them, the photovoltaics seems to be the most promising emerging technology for the electricity generation. Its rapid growth in the last years has been due to the reduction achieved in the cost of the PV panels. When planning a PV installation, it is essential to be able to estimate the production. The power of a PV-module is given by the manufacturer at standard conditions (STC), which means that the irradiance is G=1000W/m2 at normal incidence and the temperature of the module is 25˚C. However, these conditions will never be reached in a real installation. Therefore, the measured power of the system has to be adjusted for the real conditions so that the real production and performance can be estimated. Today there exists no standard method for this procedure in Sweden. The main aim of this thesis is to develop a theoretical model for the four PV-systems installed at the laboratories (building 45) of the University of Gävle to estimate the performance and production, and prove its validity by comparing with real data measured with a short time resolution (second). This will also allow to know if the power generated by the modules is the promised one by the providers. Three of the studied systems have monocrystalline silicon modules, with different schemes: one system with bypass diodes, another with TIGO optimizers, and the third one with microinverters. The fourth system has thin film modules. The theoretical model considers correction factors for the cell temperature, the angle of incidence and the real irradiation reaching the modules’ surface; as all these aspects reduce the power obtained. When studying this model for clear sunny days, it can be observed that the theoretical model adjusts perfectly for the four systems in these conditions and almost a completely linear dependence is achieved between the measured and estimated power. The worse adjustment is obtained for the thin film system, for which the theoretical model gives lower values than the real ones. However, a better approximation can be obtained for this system by adjusting the value of the correction factor for the cell temperature. Moreover, the high values obtained for the maximum power during the clear days, very close to the peak power, indicates that the maximum power value provided by the manufacturers is in concordance with the real performance of the modules. In case of cloudy days, a small-time delay has been appreciated between the data recorded by both logger. The results have been studied with the raw data, obtained worse adjusting, and correcting this time discordance, getting again accurate results from the theoretical model.

  • 1089.
    Zana, Tahsin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energimässig jämföelse med investeringskalkyl av två förskolor2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    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.

     

  • 1090.
    Zeng, Yuming
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Prospection of Swedish District Heating: the status of solar energy2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Due to the environment degradation and threats of the climate change, how to develop the technologies to use renewable energy and improve current energy systems to meet the increasing demand of human activities instead of using fossil fuels are amongst hot issues that being discussed nowadays. Due to the specific weather condition, district heating, which contains space heating and domestic hot water, is needed in Sweden. Solar energy is the most potential and environmental friendly energy resource. It can be utilized in many different aspects. The profitability of building solar heating plant for producing heat to supply the district heating in Sweden was discussed in the thesis. In order to achieve the result, central solar heating plant and solar combisystem were discussed. Information was collected from “Sciencedirect”, some related companies and institutions websites, and etc. Very few solar radiations are available during winter in Sweden, while the demands of district heating are the highest. During summer time, a lot of cities in Sweden can use the industrial waste heat to cover the district heating load, and in some cities where there is no industrial waste heat can operate biomass combined heat and power (CHP) plant to cover the heating load. Combined solar-biomass heating plant could improve the efficiency of biomass heating plant and reduce the unnecessary heat losses. Solar combisystem has a relatively high cost and complex system. The system which is able to supply some hot water for washing machine may have a good future, due to the possibility that the price of electricity in Sweden increases.

    Large-scale solar heating plants are less attractive in Sweden due to the existence of industrial waste heat and CHP plant that supplied by biomass. Combined solar-biomass heating plant would be a good system to build if there is no available industrial waste heat and biomass heating plant is used to supply the district heating. Due to the current electrical price and the cost of combisystem, it is not that attractive to build this system. In the coming future, if the transportation cost and the price of biomass itself become too high to make the CHP plant no longer cost effective, and the price of the electricity become high, the solar energy will make more contribution to the district heating in the coming future.

     

  • 1091.
    Zetterman, Emma
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Paketera en lärarbemanningsprocess utifrån ett tjänstedesignperspektiv2016Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Clockwork skolbemanning är ett rekrytering- och bemanningsföretag som uttryckte ett behov av att utveckla deras befintliga lärarbemanningsprocess. Behovet av utveckling var inte specificerat från början och skapade därför en bred ingång i projektet. Det är tre parter som är inblandade i processen, Clockwork skolbemanning hyr ut lärarkandidater till skolan.

    Genom att undersöka den nuvarande lärarbemanningsprocessen med hjälp av olika tjänstedesignverktyg har jag skapat en konceptlösning som utvecklar processen enligt användarnas behov. Konceptlösningen bygger på behov från användaren som identifierades i analysen. Konceptet är utvecklat till designprinciper som ger riktlinjer för framtida processhantering. Verktyg så som tjänstekarta och kundresa har gett inblick i de delar av processen som behöver utveckling.

    Resultatet blev designprinciper grundade på behoven hos användarna av processen. Dessa designprinciper visualiserades till en manual som ska användas av alla tre parter, för att tydligt visa på vilka Clockwork skolbemanning är och hur deras process ser ut. Manualen skapar transparens mellan de olika parterna och visar även på utvecklingen som designprinciperna skapar.

  • 1092.
    ZHANG, SHAN
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Analytical system for photovoltaic and concentratingsolar power generation2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Energy is the material foundation of human survival and development. Throughout

    human industrialization process, the fossil energy has made tremendous contributions

    in the progress of human civilization, economic and social development. For a long

    time, the development of human energy use patterns makes fossil fuels rapidly

    depleted and the consequences of environmental deterioration by this pattern lead to

    the severe challenge for mankind. Many countries start paying more attention to

    develop the new energy. The solar electricity production system is one of the main

    new energy power generations. The thesis is a guide of principle for solar power

    generation system. It focuses on comparisons between photovoltaic and concentrating

    solar power generations and analysis of their market prospects. The merits and

    demerits of these two systems will also be pointed out in this thesis.

  • 1093.
    Zhang, Taoju
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Energy simulation for improved ventilation system in a collection of Swedish multi-family houses2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Building sector takes a large part of Swedish domestic energy use. Swedish government had set goal that required energy consumption should decrease by 20% in year 2020 compared to 1995. Public house companies will play an important role in the process.

     The work studies a typical Swedish Multi-family dwelling, built in 1960s and belonging to Älvkarlebyhus AB. These buildings were given enhanced air tightness in recent years which yielded a good result. This work focuses on improving the old ventilation system and decreasing energy consumption.

     Building energy simulation tool IDA ICE was used to model the object building and to examine the effectiveness of the new system. The tested energy efficiency measures include upgraded ventilation system with heat exchanger, and the installation of demand control (DCV) to the ventilation. Both energy, environmental and economic aspects are considered in the study.

    The result showed the total energy demand decreased 35% with renovation. Total investment for all buildings correspond to 5 760 000 SEK. New system could save 237 872 SEK/year and payback time will be 24 years.

  • 1094.
    Zhang, Taoju
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Possibilities of Alternative Vehicle Fuels: a literature review2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Historically, gasoline and diesel have been used as vehicle fuels for a long time. But the decline of oil supply and unstable oil price drive people to find alternative energy for vehicle fuel. Alternative energy solutions may shift energy consumption to less carbon, less pollutions and provide more energy diversity. These issues are investigated in the present literature review.

     

    The first part of the thesis introduces different kinds of alternative energy for vehicles, such as biofuel, natural gas, hydrogen, liquefied petrol gas, electricity and compressed air. The presentations includes their utilization, production, environment effect, running performance, fuel property, market share, running and investigate cost and production barriers. The second part of the thesis work compares the properties of the alternative fuels and discusses the advantages and drawbacks of different types of fuel energies.

     

    Compared with traditional fuels, alternative fuels have superiority in environment impact, sustainability and energy efficiency. Some of them have been used in reality and show a potential as future fuels. The author found that natural gas and liquefied petrol gas have low running costs, better environment performance and acceptable running range, and thus are able to substitute conventional fuels in the short term. Biofuel has better sustainability than gasoline. It will probably become more sustainable and cost effective in the mid-term period. Electricity can also become a future fuel in mid-term period since it has excellent emission performance and low running costs. Hydrogen is expected to substitute conversional fuels in the long term due to high investment costs and current unsustainable production pathway of the latter. The compressed air turned out not suitable for substituting conventional fuels because of poor efficiency and running range performance.

  • 1095.
    ZHANG, YAOYUN
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Building energy system simulation: A case study renovation of an apartment located in Gävle Sweden2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 1096.
    Zhang, Ying
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    China's building energy consumption and how to get energy efficiency.2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 1097.
    Zhang, Ying
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    You, Song
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    energy security in China- The impact of Renewables2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 1098.
    Zhu, Xuanlin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    A Feasibility Study of Using River Water in University Cooling System2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is to study the feasibility of using river water from Gavleån in the cooling system of University of Gävle. The project is proposed by the campus service manager Akademiska Hus AB which intended to replace the current cooling production system with the water cooling system to reduce the electricity cost in cooling production. The river by direct distance is 600 meters from the university, the river water is to be extracted from the river via a pump house, flow through pipeline buried underground and delivered to the equipment house of Akademiska Hus.

     

    Most water source cooling prefer water body with decent depth which contain low temperature water to use as free cooling source, but the issue that limits the practice is, the decent depth is not a very common feature of most water body near or within urban area. Like Gavleån which has an average depth of not over five meters while the sufficient depth is over 50 meters for the least or 70 meters to 100 meters often. So study the potential of using rather high temperature water from shallow water body can be of high interest for most cooling consumers.

     

    The thesis progressed through the work in five parts. To introduce cooling in general starting with literature review, the concept, the mechanism, the device for end use and production, the demand of cooling and the reason behind it. Followed by case studies of water source cooling projects worldwide, which is mostly deep water source cooling, and another case of the local hospital cooling system that extract water from Gavleån, demonstrate the use of shallow water body in assisting cooling production, it gives some insights how the potential if similar system is to be implemented in the campus, which is mounted on the same river. Several tours to the hospital were taken to acquire data and understanding of the system.

     

    Then the water temperature measurement from Gavleån in 2014 summer is presented. The measurement was carried out at a small dock by the river side during July to September of 2014. The measurements show the temperature of river water has been increasing which limits free cooling throughout the year, additional refrigerator is required to produce chilled water. The river water, in the hot seasons is used as cooler for the refrigerator and in cold season can be used for free cooling directly. Simulation of IDA-ICE gives the cooling demand of modelled building blocks, the output of cooling production season (consistent with the hot seasons) matches the cooling consumption data from Akademiska Hus by an error of 1% (414743 kWh of simulated result to 415270 kWh in documentation of Akademiska Hus).

     

    To meet the demand of cooling and select more cost-effective refrigerator type, consumption and COP (COP: Coefficient of Performance) are calculated for compressor chiller and absorption chiller with basic cooling cycle for both. The results shown compressor chiller has much better performance but also higher consumption in electricity, while absorption chiller has rather low COP value in comparison but the need of energy input is much less given by its major consumption of energy is heat from hot water, already a purchased item by the university from district heating network. Cost-effectiveness wise speaking absorption chiller is a more optional choice. Reasonable values of assumption are largely employed in the calculation to select the better candidate and bring certain errors, which is then exam in sensitivity analysis to weigh the alternative parameter and the outcome from it.

     

    The last part is to estimate the cost of chillers and pipeline, for the concern of minimizing errors due to uncertainty the operation cost, labor cost and future energy price are not included. As the calculation turns out the payback year of the new system can range from 7 to 12 years by different refrigerator setup and pipeline routine design, which is considered within the life time of the chiller and pipeline, also lower than the current cooling cost of the university and therefore concluded as promising investment.

     

    Discussion and conclusion exam and finalize the whole thesis work. For the uncertainties of the calculation, the lack of information and data, which are improvements, can be done in future work. Also the improvements in other perspectives noted in terms of better load management for the cooling production units so the cost of equipment can be reduced, changes in building attachment and cooling device to reduce the demand of cooling, etc. But mostly draw the conclusion that with proper system configuration shallow water body can be helpful in reducing cooling consumption, and be a promising option for cities that have access to such water body. 

  • 1099.
    Zhu, Xuanlin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Exploring the possibility of applying seasonal thermal energy storage in south-west of China2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Buildings energy consumption is rising continuously with massive urbanization progress, which then results in high greenhouse gas emission. A standing example is the urbanization process going on in the south-west part of China. Much has been discussed for improving building energy performance. However, to take another point of view, renewable energy source for buildings is a solution worth considering, for instance STES, which gains thermal energy from the sun, delivers it to buildings for space heating and hot tap water, also restores the solar energy in hot seasons in the storage system for the need of cold season.The aim of this paper is to couple the technology of STES with practical situation, explore the possibility of applying STES in south-west of China. This thesis work takes an estimation approach to weigh the possibility. The building project studied in this thesis is a campus project in the city of Guiyang, one of four major cities in the region of south-west China.Case study involves existing STES projects in Munich Germany and Anneberg Sweden, the performance evaluation of the Anneberg project is later to serve as an example in system gain & losses proportion, to guide the estimation work of the campus project.The estimation conclusion is drawn based on a cross-sectional analysis method, take the technology of STES, the practiced STES project and building projects in China as three loops visually, and observe how much they overlap each other. Behind the visual illustration, the overlapping is assessed with several factors, for instance possibility of storage system at location, possible STES performance and solar irradiation condition at site location etc. If most of these factors are checked to be “Ok” or “Good”, then the overlapping area is considered “large” enough, and therefore suggests a decent chance to implement STES system in the south-west China.A solar gain and sunlight simulation from a new police station energy consumption report assists in calculating the possible solar gain for the campus project, as the very close distance between these two sites (30 km) promises them the very similar solar irradiation condition. While the energy consumption of the studied campus project offers the energy demand for space heating and hot tap water in the need of 19,000 students, which is to be evaluated as the task of the STES system in the estimation work. Both building project reports are filed by GARDI (Architecture design research institution of Guizhou).Some key factors have been calculated and estimated, the heat demand of the studied campus project in Guiyang is 5,558 MWh/year, and the possible solar gain of this campus complexity is 4,900 MWh/year based on the gain & losses proportion of the Anneberg project evaluation. Due to the very different climate condition of Guiyang and Anneberg, as well as other uncertain factors such as effective roof area, solar collector efficiency, a sensitivity analysis evaluated the result with different parameters in changes of percentage. Final results in the changes of effective roof area at 80% and 85 %, borehole losses at 50% and 45%, available solar gain at 38%, STES system is shown to be capable of providing sufficient heat to buildings. If the heating demand and hot tap water, in the case of the campus project alone are all covered by STES system, there will be a reduction in CO2 emission of 5,368 tons/year.Cross-sectional analysis concludes four out of eight factors checked as “Good” and two as “Ok”, other two as “Unsure”. Other three cities (Chengdu, Kunming, and Chongqing) are brought to comparison later regarding climate condition. Besides Guiyang, two out of three are evaluated to have potential of STES implementation according to their sun hours, annual average temperature etc. STES system is estimated to be possible for implementation in south-west of China as the conclusion.

  • 1100.
    Ängalid, Filip
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Utredning av behovsstyrd ventilation: En jämförelse mellan CAV och VAV2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna rapport är ett examensarbete på C-nivå som görs i sammarbete med teknikkonsulten Ramböll. Det vanligaste sättet att ventilera en byggnad idag är med så kallad CAV-ventilation (Constant Air Volume). Denna metod bygger på att ett luftflöde bestäms för rummet och upprätthålls med konstant flöde. En annan metod är så kallad VAV (Variable Air Volume) som bygger på att flödet varierar efter behovet. Anledningen till varför man väljer VAV istället för CAV är att med CAV finns det ofta en stor risk att man överventilerar ett rum eller byggnad, just på grund av att flödet är konstant. Problemet med VAV är att det är en högre investeringskostnad än för CAV så metoden lämpar sig bara där energibesparingen är så stor så den täcker mellanskillnaden i pris. Denna utredning visar i vilka typer av rum som det kan löna sig att installera VAV istället för det traditionella CAV-systemet. För att undersöka detta sker simuleringar av fiktiva modeller i programmet IDA Indoor Climate & Energy (IDA). IDA är ett simuleringsverktyg som används till att simulera den termiska komforten i byggnader samt byggnadens energianvändning. De olika rumstyperna som simuleras är: klassrummet, kontoret och mötesrummet. De olika fallen är utformade så att de liknar så som de ser ut i verkligheten både till geometri och nyttjandegrad. Om något av fallen visade sig vara en bra kandidat för att förse med VAV fortsätter utredningen med att fastställa hur stort bör flödet vara för att energibesparingen ska bli så stor så att det täcker investeringskostnaden. Den ekonomiska kalkyleringen sker både med en livscykelkostnadsanalys och med en enklare återbetalningstidskalkyl. Resultatet för simuleringarna visade att den enda rumstypen i denna utredning som var lönsam var mötesrummet. Klassrummet och kontoret visade sig båda ge en förlust. Detta var eftersom nyttjandegraden för dessa rum var så pass hög så att ventilationen med VAV var igång nästan lika mycket som för CAV. För mötesrummet var nyttjandegraden betydligt lägre vilket innebar att energibesparingen blev så pass hög att den täckte den höga investeringskostnaden. För mötesrummet gjordes sedan en flödesanalys som visade att rummets luftflöde bör vara dimensionerat för mellan omkring 20 – 30 personer för att vara en lönsam investering. 

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