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  • 101. Raj, Uday
    et al.
    Li, Ziqi
    Ke, Ying
    Wang, Faming
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, China.
    A study of thermal comfort enhancement using three energy efficient personalized heating strategies at two low indoor temperatures2018In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 143, p. 1-14Article in journal (Refereed)
    Abstract [en]

    There is great potential to apply personalized heating for saving energy and enhancing individual thermal comfort in buildings during cold weather. This study investigated the enhancement of thermal comfort of occupants using personalized heating systems at low indoor temperatures. Three personalized heating systems are chosen for this work, i.e., a radiant heating panel with a heated table pad (denoted as HB1), a heated chair with a heated floor mattress (denoted as HB2), and electrical heating clothing (a heated jacket and trousers, denoted as EHC). The effectiveness of three selected heating systems on overall/local body thermal comfort of female occupants under two indoor temperatures of 15 and 18 degrees C has been investigated. Total energy consumption of these heating systems has also been examined and compared. Thermal acceptability of EHC was better than HB1 and HB2 at both two temperatures. Overall thermal sensation vote (TSV) in EHC was significantly better than that in HB1. Mean skin temperature remained within the thermal comfort range (32-34 degrees C). In order to achieve thermal comfort on 70% and 80% of the inhabitants at various body parts, local body TSVs should be within - 0.43 to 1.87 and - 0.36 to 1.87, respectively. Further, EHC consumed < 15 W power, which accounts for only 4.4% and 14.8% of the total power consumed by HB1 and HB2, respectively. Based on the evidenced thermal comfort improvement potential and low power consumption in EHC, it is thus recommended to use EHC for the thermal comfort enhancement of inhabitants under low indoor temperatures.

  • 102. Raj, Uday
    et al.
    Li, Ziqi
    Ke, Ying
    Wang, Faming
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, China.
    Personal cooling strategies to improve thermal comfort in warm indoor environments: comparison of a conventional desk fan and air ventilation clothing2018In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 174, p. 439-451Article in journal (Refereed)
    Abstract [en]

    The study examined and compared the performance of two personalized cooling strategies (conventional desk fan [DF] and air ventilation clothing [VC]) in three warm indoor environments. Two cooling methods were selected so that the effect of different local body parts cooling can be analysed on overall thermal comfort of female participants. Three warm indoor conditions (28.0, 30.0 and 32.0 °C; 50% RH) were selected with an aim to determine maximum possible air temperature which can be maintained indoors without compromising with thermal comfort of inhabitants. Results showed that performance of both the two cooling methods are similar in terms of perceptual responses and mean skin temperatures at all three air temperatures. Mean torso temperatures in VC were significantly lower than those in DF at three studied indoor temperatures. It was concluded that the effect of torso cooling on overall sensations was equivalent to combined forehead-hand cooling for the studied indoor conditions. VC is recommended for indoor and normal office work environments with air temperatures up to 32.0 °C because it can save significant cooling energy as compared to conventional desk fans.

  • 103. Ramirez-Villegas, Ricardo
    et al.
    Eriksson, Ola
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Assessment of renovation measures for a dwelling area - Impacts on energy efficiency and building certification2016In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 97, p. 26-33Article in journal (Refereed)
    Abstract [en]

    The European Union has an ambitious plan to reduce energy use and emissions by the year 2030. The building and real estate sectors have a great potential to help reduce emissions by energy efficiency. However, different energy sources and environmental standards affect the decision making of these major renovations in the existing stock. This study investigates how different renovation strategies affect the energy rating of a selected Building Environmental Assessment Tool and analyses the consequences in terms of greenhouse gas emissions for the local district heating system. Both building energy simulations and energy systems cost optimization were used to determine the energy use and local emissions. The results of different renovation scenarios were used to evaluate the rating in the selected tool and the impact in the district heating local emissions. The used methodology illustrates how energy efficient renovation impacts on the district heating system's local emissions. However, a bias towards resource classification within the Swedish Building Environmental Tool, Miljobyggnad, needs to be addressed in order to assess the impact of local emissions.

  • 104.
    Renman, Josefine
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Renovering av utanpåliggande balkonger2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Balconies have been built in Sweden for over 200 years and are now very popular. They are generally exposed to a lot of strains and are often a common thermal bridge. The balconies at concrete multifamily building from the 1960-1970s need to be renovated, among others. They were built with the technology of the past which means that they have a thermal bridge.

    The report is made for guiding property owners through the renovation process of an external concrete balcony. It summaries the markets methods based on interviews and literature studies. The interviews where qualitative with the help of: a skilled constructor, a concrete expert, a paving expert, an experienced building manager and a balcony railing expert.

    The thesis describe concrete and reinforcement; their structure and their properties. A balcony’s different damages are describes. For example, the damages that can occur on concrete are frost weathering, reinforcement corrosion, chemical attrition, cracks and abrasion.

    Balconies varying construction from late 1800s to today’s technology are explained with text and figures. Descriptions are given on their concrete, rails, any thermal bridge and load baring function. The construction has changed from constant steel beams to isolated balcony connections.

    How balconies can be checked is described; ranging from ocular inspections to taking different samples to a laboratory. Finally, balconies different repairs due to damage are described. In case the balcony is too damaged to be able to be repaired, there are several examples of how a new construction can be applied. This is often with traction rods and columns.

    The conclusion of this work is that an analysis for a balcony should proceed from simple questions about the damages and the materials. These questions in consultation with knowledge about damages, controls and corrections are a suitable way to decide which action to make for a balcony. The most important thing is to check the balcony's structural parts so there is no risk of collapse and also that no falling concrete can occur. 

  • 105.
    Riis, Maria
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Detaljlösningar i grundkonstruktioner gjorda i betong2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To make the work more efficient, and to maintain a high and competitive quality regarding the design and dimensioning of detail solutions in basic constructions made in concrete. At JBR Konsult they have the need to work out a calculation template to ensure that this is done according to the applicable norm, Eurocode. This work has been aimed at meeting their needs. Details that the work deals with are pillar soles and edge beams.

     

    The calculation templates are developed according to Eurocode 5, which is the euro code that deals with concrete structures. The calculating template for the column sole controls bending moment, shear strength and risk of punching. Regarding the edge beams, it is the step that becomes dimensioning since the cross force becomes very small. This means that it is only the torque capacity that is controlled.

     

    The conclusion that can be drawn after this work is that, it is not a question of stopping as much reinforcement as possible, but that there are several aspects that play. For example, the reinforcement ends up at a correct distance from the outer edge of the concrete.

  • 106.
    Risberg, Daniel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Optimering av förband till vindkryss för höga byggnader i limträ2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    More and more tall buildings are made from glulam in Sweden. This brings an incentive to make the construction design work more efficient by the use of pre-designed solutions. This examination work aims to design and dimension pre-designed solutions in the form of a set of joints to bind together tie-rods of steel with columns and braces of glulam. These shall have a drawing library with instructions for selection of joints and basis for construction drawings established in Autocad. Furthermore, they shall have components ready in Tekla Structures to further facilitate the construction design work. The joints are designed using screws and dowels. Of importance for this work is that the joints are well designed regarding use of space and ease of montage. The load capacities of the joints shall be calculated in accordance with applicable Eurocode. The result was a set of joints allowing full use of load capacity for tie-rods in strength class 8.8 in the dimensions M16, M20, M24 and M30 at an angle of the tie-rods between 28° och 56°. Instructions and basis for construction drawings have been established in Autocad and are attached as an annex. Components in Tekla Structures have been created. In conclusion, the work has achieved its goal with the exception of a few deviations from the requirement specifications, and the joints seem to be fit for use in construction design and thereby fill their purpose.

  • 107.
    Risén, Simon
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Upplagstryck för träbalkar enligt Eurokod 5 - Problematik och förstärkningsåtgärder2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When Eurocode 5, design rules for timber structures, was introduced in Sweden there wasalso a reduction in strength values for structural timber, and especially when it comes tocompression perpendicular to the grain. Earlier on, before Eurocode 5, the capacity ofScandinavian glulam L40 was 8 MPa which now was to be revised by the Technical ResearchInstitute of Sweden (SP). The new value was set to 2.7 MPa and the new revised glulam wasnamed CE L40c. A problem now arose, namely so that existing structures (which aredesigned after the old Swedish standard BKR) no longer can be designed in the same way.The purpose of this thesis was to:• Find out why the reduction in capacity for compression perpendicular to the grainoccurred• Make a few examples through calculations on how to fix this problemThe studies of literature which this thesis is based upon indicates that the reduction incapacity was due to the very nature of how the Eurocodes determines the strength classes,and how it is different from BKR. The big difference is that in the Eurocodes there is noutilization of the physical phenomenon where the loaded wood fibres distributes the load to anearby unloaded fibre. This phenomenon greatly increases the capacity at compressionperpendicular to the grain. It should be mentioned that this work also indicates that thedesign process does not have the same impact on the design of structures as the grading ofstrength classes has.According to the second purpose of this thesis, a set of calculations were made whichindicates appropriate methods of reinforcement of a wooden beam. The three methods are:• A steel plate which is placed between a column and a beam to increase the supportlength and therefore spread the support stress over a larger area of the beam• Steel screws which are screwed into the beam at the support, perpendicular to thegrain• Wooden rods which are glued in place inside the beam at the support, perpendicularto the grainAll calculations were made with a load of 100 kN, cross section of the beam is 215x630 mm,cross section of the column is 215x150 mm and support length is 150 mm.• When the width of the steel plate is 215 mm and steel grade s235 is used, the steelplate dimensions required are, according to calculations, thickness of 15 mm andlength of 270 mm.• With 6 steel screws, M12 4.6 and a penetration depth of 400 mm, a new characteristiccapacity of 5.6 MPa was obtained.• With 6 wooden rods made out of birch, 19 mm diameter and a penetration depth of400 mm, a new characteristic capacity of 5.07 MPa was obtained.

  • 108. Ruud, Svein
    et al.
    Östman, Leif
    Orädd, Philip
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energy savings for a wood based modular pre-fabricated facade refurbishment system compared to other measures2016In: Sustainable built environment Tallinn and Helsinki Conference SBE16: build green and renovate deep, 2016, p. 768-778Conference paper (Refereed)
    Abstract [en]

    There is a need to focus on energy efficiency for the existing buildings, especially buildings erected before the energy crises in the seventies, as these buildings provide a massive potential for improvements in energy performance. The facades of these buildings are also facing an increased need for a face-lift. There are a large number of such facades in all these countries. One problem is that these buildings must be refurbished at low costs and with limited disturbance to the users/tenants. In this study we have investigated the energy efficiency of a modular pre-fabricated facade refurbishment system based on wood and compared it to two existing systems for on-site mounting of additional insulation. These existing alternatives require a lot of on-site works. Hence prefabricated solutions would, of course, offer advantages. There have been several attempts to develop such solutions in recent years but so far none of them have provided an acceptable solution. This approach is based on an alternative with small scale prefab elements with a simple assembly process. The energy analyses concentrate on thermal bridges and U-values, relating it to the total energy performance and compared to the current situation and comparable refurbishment methods. We have mainly focused on the wall structures but as a comparison also other energy saving measures has been investigated shortly. For the very common reference building the pre-fabricated solution is the third most effective energy measure. We have also conducted a study of the energy efficiency regulations in different Nordic countries in order to see what the current legal framework is, and tried to sort out how far it is possible to improve energy efficiency by means of improving the U-value of the exterior walls. The outcome is a verification of the energy efficiency of the chosen prefab structure as a solution for refurbishment. The advantages are to be found in the dry production process combined with a simple and fast assembly on site. Similarly, there are advantages in the reduced number of thermal bridges and in the potential for the use of recyclable materials. Another advantage is that it has an integrated air tightness that is mounted on the outside of the existing wall. This is part of a larger research project aiming at cost efficient and sustainable solutions for refurbishment of facades in a Nordic context. In the larger research project, we have also conducted a cost-benefit analyses and studied moisture conditions in order to see how far this solution might be feasible. The ultimate aim is to test a product and compare the findings from demo projects in the three countries Norway, Sweden and Finland.

  • 109.
    Röjmyr, Robert
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energiverifiering av Bromma flygplats ankomsthall: Verification of energy performance at Bromma airports arriving hall2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today housing and service accounts for 40 % of Swedens total final energy usage.Buildings have a very long lifespan and the energy-related decisions taken todayaect both costs and the environment for decades to come. Therefore, the NationalBoard of Housing, Building and Plannings building regulations require thatenergy verification be carried out on buildings within two years after completionof construction. Bromma Airport Arrival Hall B93 underwent extensive rebuildingand was reopened in the fall of 2017. Therefore, on behalf of Ramb¨oll, an energyperformance verification has been carried out for the building. The energy performanceverification has been carried out in the form of a masters degree project inenergy engineering at Umeå University. Energy verification can be performed bymeasurement/normalization or calculation, in this case, energy performance verificationwas done through calculations using IDA ICE software. During the project itwas required that certain delimitations were made due to lack of access to premisesand lack of documentation but through assumptions energy performance verificationcould be accomplished. The results shows that the building meets the energyperformance requirements from the National Board of Housing, Building and Planningsbuilding regulations (BBR).The project also included project targets beyond a conventional energy performanceverification. In addition to the energy performance verification, the project containeda comparison between the energy calculation submitted for the planning applicationfor the rebuilding with the energy calculation for the energy performanceverification. Any deviations were to be identified and explained. In addition, additionalenergy performance requirements were to be identified. The simulated modelsfrom the planning application and the energy performance verification showeda dierence in both outwards appearance and heating-, ventilation- and sanitationsystems. The report includes a detailed explaination of the comparison. Swedavia,owner of the property, proved to have internal energy requirements for its buildings.These are presented in detail in the report, and the results of the project shows thatthe building also reaches these requirements.

  • 110.
    Rönnbäck, Jonathan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Optimering av materialkombinationer i bärande stomme2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med arbetet var att dimensionera en stomme i limträ till en redan befintlig byggnad för att sedan jämföra den med den stomme som byggnaden i nuläget har.

     

    Dimensioneringen gjordes till stor del i datorprogram men i vissa situationer krävdes handberäkningar. Det som dimensionerats var bärande balkar, pelare och åsar, samt två stycken anslutningsdetaljer. En 3D-modell gjordes av limträstommen samt stomplansritning, sektionsritningar och detaljritningar.

     

    Alla innermått gick att behålla så som de är i den befintliga byggnaden, vilket var en av de stora frågorna innan arbetet. Detta gör att byggnaden skulle gå att använda i samma utsträckning som den i dagsläget gör. De problem som uppkom var att dimensionerna på en del balkar blev väldigt stora, då det är långa balkar som ska ta upp stora krafter, samt att det inte gick att behålla skärmtaket som det är i nuläget utan utvändiga pelare behövdes vilket inte är optimalt. Detta skulle kunna gå att lösa om takbalkarna kunde låtas sticka ut från väggen och då skapa ett skärmtak. Men med tanke på syftet för detta arbete valdes det alternativet bort.

     

    Fördelarna med limträstommen som framkommit ur detta arbete är att den är billigare, mer miljövänlig, tål brand bättre samt att den i mångas tycke är mer estetiskt tilltalande. Nackdelar är funktionen, många detaljer blir svåra att utföra endast i trä, samt att väldigt höga tvärsnitt behövs på en del balkar för att klara av lasterna och brandklassen.

  • 111. Schiavon, Stefano
    et al.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Chang, Wei-Chung
    Nazaroff, William
    Effect of air temperature and air movement on thermal comfort for tropically acclimatized persons2015Conference paper (Refereed)
  • 112. Schiavon, Stefano
    et al.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Civil and Environmental Engineering, Nanyang Technological University, Singapore; Berkeley Education Alliance for Research in Singapore, Singapore.
    Donner, Yoni
    Chang, Wei-Chung
    Nazaroff, William
    Thermal comfort, perceived air quality and cognitive performance when personally controlled air movement is used by tropically acclimatized persons2017In: Indoor Air, ISSN 0905-6947, E-ISSN 1600-0668, Vol. 27, no 3, p. 690-702Article in journal (Refereed)
    Abstract [en]

    In a warm and humid climate, increasing the temperature set point offers considerable energy benefits with low first costs. Elevated air movement generated by a personally controlled fan can compensate for the negative effects caused by an increased temperature set point. Fifty-six tropically acclimatized persons in common Singaporean office attire (0.7 clo) were exposed for 90 minutes to each of five conditions: 23, 26, and 29°C and in the latter two cases with and without occupant-controlled air movement. Relative humidity was maintained at 60%. We tested thermal comfort, perceived air quality, sick building syndrome symptoms, and cognitive performance. We found that thermal comfort, perceived air quality, and sick building syndrome symptoms are equal or better at 26°C and 29°C than at the common set point of 23°C if a personally controlled fan is available for use. The best cognitive performance (as indicated by task speed) was obtained at 26°C; at 29°C, the availability of an occupant-controlled fan partially mitigated the negative effect of the elevated temperature. The typical Singaporean indoor air temperature set point of 23°C yielded the lowest cognitive performance. An elevated set point in air-conditioned buildings augmented with personally controlled fans might yield benefits for reduced energy use and improved indoor environmental quality in tropical climates.

  • 113.
    Sedin, Johan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Dimensionering av stålstomme och brandskyddsfärg vid en given brandteknisk klass2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    WSP Structures in Umeå wants the student to propose a preliminary design for a steel frame with a given input, considering the ultimate limit state and fire. The project has been limited to design the frame for the ultimate limit state and the fire design has been limited to calculate the amount of fire retardant paint needed for fire classification R30 for building components. The frame is delimited to columns, beams, horizontal stabilization and connecting joints between parts. With the help of theory, the resistance and the design amount of fire protection are verified, of which the results are verified.

     

    As a solution, a model is created in the modeling software FEM-Design where load combinations are created by the given input and assumptions. Using the software´s design tool, the needed sections for columns and beams is calculated. Load effects that accords at joints is indicated by the program and is used to design joints and connections between parts according to SBI:s publications for beam-column connections and column footings. Most utilized elements were the “middle column”, which were designed to a HEA 200 profile with an 80% utilization. Detailed results are presented with tables which presents the utilization for each element. Designed columns, beams and joints can be found in level, section and detail drawings.

     

    With the help of the created FEM model and used theory about fire design, the amount of fire retardant paint is calculated with the accidental load combination. The accidental load combination generates a lower utilization, which is used to calculate the needed amount of paint based on the manufacturer´s table. Columns received an amount of 750 g/m2 and beams received an amount of 1000 g/m2. Horizontal stabilizing elements didn´t receive any protection because it could be shown that columns could be calculated with a fixed support during the accidental load combination with a significant lower horizontal load.

     

    The student thesis emphasizes the importance of finding a balance between the amount of paint and section and embracing a discussion about fire protection for joints. The utility rate for columns and beams became a guideline for the utility for joints since the amount of paint applied on the beam and connecting joints is the same, it would be a problem for example if the joint is utilized more than the connected beam. Also, determining the amount of paint needed is difficult if different steel grades are used in a joint and if details such as stiffeners are narrower than the thickness of the connecting column/beam.

  • 114.
    Selin, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Underhållsplanering2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To make the life length for a property as long as possible, management and maintenance is required. Maintenance can contain many different parts of work, both at and around the property. Locating each maintenance item is difficult and therefore a maintenance plan can be a helpful tool. It makes work easier and increases the understanding among all parties concerned. The main functions of a maintenance plan is to point out the future maintenance for both the property area and the land area, and also all the installations. This makes it easier to plan what and when work should be accomplished. The maintenance plan does not just show the future work, it also plans for the financial expenditure. For a real estate company and for a housing cooperative, it is incredibly important to know the future expenditure. Maintenance planning can divide in two types, one for the external and common areas, and one for each separate apartment. This report is based on the planning of external and common areas for two neighborhoods in Umeå. The report takes the whole process of the maintenance plan in consideration and it starts with the fundamental work of a preliminary study and calculation of all areas of the properties. After that the inspection work starts, where all the different steps easily follows. It all ends with a summary of the resulting data for the complete maintenance report. To make the summary as clear as possible a computer program is used, called SUMMARUM. The financial section of the maintenance plan is presented in the form of cost estimates which are also compiled and calculated in SUMMARUM. This creates a document that is easy to follow and shows an overall picture of future maintenance and financial expenses. A complete maintenance-plan can be found in the annex of this report.

  • 115.
    Sjögren, Jan-Ulric
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energy performance of multifamily buildings: building characteristic and user influence2007Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Today many professional property holders use different types of software for monthly energy analyses. The data is however often limited to energy and water use, that is paid for by the property holder. In year 2001, financed by the Swedish Energy Agency, the first steps were taken to create a national web based data base, eNyckeln. A property holder may then enter consumption data together with about 50 other building specific parameters to this data base in order to enable benchmarking and energy performance evaluations. Due to EU-regulations and the increasing awareness of energy and environmental issues there is a large interest in evaluating the energy performance and also to identify effective energy retrofits. The used energy performance indicator is still only the annual energy use for heating per square meter of area to let, kWh/m2,year, despite the fact that monthly data often are available. The main problem with this indicator, which is the stipulated measure, is that it reflects a lot of user influence and that only a part of the total energy use is considered. The main focus of this thesis is to explore the possibilities, based on the national data base, to extract additional energy information about multi family buildings (MFB) using monthly data in combination with different assumed consumption pattern but also to identify potential for energy savings. For the latter a multivariate method was used to identify relations between the energy use and building specific parameters. The analysis gave clear indications that the available area, the area to let, is not appropriate for normalization purposes since the remaining heated area can be significant. Due to this fact, the analysis was mainly limited to qualitative conclusions. As measure of the buildings energy characteristic, the total heat loss coefficient, Ktot,(W/ºK) is determined and the robustness for the estimate of Ktot to different assumptions of user behaviour is investigated. The result shows that the value of Ktot is fairly insensitive to different indoor temperature, use of domestic hot water and household electricity. With the addition of m2 it can of course be used for benchmarking. Using the mentioned measure of the buildings energy characteristic for validating the energy performance has a clear advantage compared to the traditional kWh/m2, since the user behaviour is of minor importance. As a result of this an improved analysis of the energy performance will be obtained. A guarantee for new buildings energy performance based on this method is therefore a challenge for the building sector to develop.

  • 116.
    Skoglund, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Dimensioneringshjälp för stabilisering av flervåningshus.2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Construction in cold climate presents many challenges due to the stresses of which the structures are exposed. The research project Attract strives to achieve attractive and sustainable living in a subarctic climate, with basis in Kiruna and Gällivare. Tyréns AB is part of this project and want to make the construction process more efficient by industrializing the production of houses with prefabrication of modules to reduce the cost and time for both design and production.

     

    The idea for this thesis is to create a calculation model that can be used to quickly obtain the forces stabilizing towers of prefabricated disc elements are exposed of. The idea is to have few specific values ​​and instead give the user of the model the option to use custom variables depending on the situation, which would mean that the model can be used on several different occasions.

     

    This work has resulted in a calculation model using an Excel data file where calculations are performed automatically and delivers the forces for the stabilizing tower. The model allows multiple variables which mean that it can be used in a variety of situations.

     

    Because the work has involved manual calculations there are some natural sources of errors to keep in mind. The calculations made to create the model have become fragmented due to continuous changes during the work and therefore unsuitable to present. This is why there is an annex to this report to show the method of calculations. For further work there are numerous opportunities to develop the calculation model to broaden or refine the results.

  • 117.
    Soleimani-Mohseni, Mohsen
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nair, Gireesh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Hasselrot, Rasmus
    Energy simulation for a high-rise building using IDA ICE: investigations in different climates2016In: Building Simulation, ISSN 1996-3599, E-ISSN 1996-8744, Vol. 9, no 6, p. 629-640Article in journal (Refereed)
    Abstract [en]

    In this paper a model of a high-rise building is constructed in the simulation program IDA ICE. The model is based on an IFC-model of a demonstration building constructed in Ljubljana, Slovenia, as part of an EU-project, EE-high-rise. The model's energy performance was simulated for four cities: Umeå (Scandinavia), Ljubljana (Central Europe), Sibenik (Mediterranean) and Dubai (The Persian Gulf). Furthermore, the climate envelope of the building was modified with the aim to improve the model's energy performance in each of the regions. The results were evaluated according to the energy requirements of passive house standard by the German Passive House Institute. The analysis suggests that the reference building model, which itself incorporates several energy efficient components, was unable to meet the German passive house standard in none of the four cities (Umeå, Ljubljana, Sibenik and Dubai) studied. By providing a combination of energy saving measures, such as modifications of thermal resistance of building envelope, the building may be able to meet the passive house standard in Ljubljana. The analysis concludes that the reduction in window area results in reduction of both heating and cooling demand. Increase in the thickness of the insulation and the thermal resistance of windows reduces the space heating demand for Umeå, Ljubljana and Sibenik (not applied for Dubai) while increasing the cooling demand for these cities. Increased airtightness has marginal effect on heating and cooling demand for all investigated cities. Reduced thermal resistance of windows will decrease cooling demand for Ljubljana, Sibenik and Dubai (not applied for Umeå). Reduced insulation thickness (not applied for Umeå) will decrease cooling demand for Ljubljana and Sibenik but not for Dubai. Reducing the insulation thickness may often result in reduced cooling demand for moderately warm countries since the average outdoor temperature could be lower than the indoor temperature during part of the cooling season. In those situations a reduced insulation thickness can cause heat flow from the relatively hot inside to the colder outside. However, for hot climates like in Dubai where outdoor temperature is higher than the indoor temperature for most of the year, reducing the insulation thickness will increase the cooling demand. This result suggests that the insulation thickness must be chosen and optimized based on heating and cooling demand, internal heat gain, and outdoor climate

  • 118.
    Stenberg, Anna
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lufttäta klimatskal i prefabricerade betongstommar och pelar- balksystem med lätta utfackningsväggar2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden's periodically very cold climate requires a building to be equipped with a sufficiently heat-insulating climate scale so that we can keep energy consumption down, ie maintain the energy supplied. According to the Energy Performance Directive, all new buildings built in the EU after 2020 must be close to zero energy buildings. Although the term has not yet been fully defined, it can be summarized that it is the Boverket, which specifies the requirements for energy conservation and thermal insulation. However, there are no specific requirements for measurable values regarding air density. It is now up to the builder to make demands and these are formulated in the program work. At new production, the inner airtight layer is devoted to a lot of time and attention. There are often standard solutions, but some details are more labor-intensive to solve and one of these is floor joints. However, consensus appears to exist regarding existing research on climate scale with heavy exterior walls such as sandwich elements. This type of construction has very good conditions for providing a sustained low transmission loss and good air tightness in the long run. Historically, the joints have been the weak point. The purpose of this study is to investigate the prerequisites for a standard solution in the steel / HD / F meeting against curtain walls with the aim of tightening this type of structural component. An investigation will also be made to get a better understanding of air tightness and diffusion density problems in the climate shell, partly in precast concrete buildings, as well as in post- beam structural systems with light curtain walls, to gain a better understanding of whether this can be derived from different stages of the construction process. Experiences from different professions were collected and evaluated against the existing theory. A total of 26 companies were interviewed either face to face or via email and telephone. The study shows that problems still arise in the joints between concrete elements. The interviewees testify to joints that crack, are defective, are difficult to access, and that the casting fails or is forgotten. So, even though the conditions are high for climate scale with heavy exterior walls to maintain a sustained low transmission loss and good air tightness, there is scope for further studies in this area. Among the suggestions given by those interviewed to a standard solution, one proposal appears more interesting than the others, and it is to supply the steel beams flanges with bitumen bands before the concrete bellows are put into place. However, how well this proposal works in practice remains to be seen. There are some very good ideas from the interviewees on how to best fit the plastic film to achieve maximum air tightness but there must basically be a balance between how insufficient information may be on a drawing and how much projectors and designers should expect craftsmen to solve on site.

  • 119.
    Thors, Mikael
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Inslitsade väggskarvar2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Industrial timber construction is more and more used in Sweden. To be able to build in cost efficient way today, several different types of houses with prefabricated wall, floor and roof elements are being built. The biggest market today is single-family homes but more and more apartment buildings are being built with prefabricated elements. It was up to the code change in 1995 not allowed to build multi-story buildings made of wood.

    In this thesis the connection designed earlier for the Masonite Flexible Byggsystem is further developed. The original assembly dowel has been replaced by a slotted-in steel plate connection with screws connecting the plates and wall elements. Several different combinations of plates and screws are tested to develope a connection with high failure load and ductile behavior.

    The strength of the joints was as high as up to 75 kN. It's more than what I imagined when I started with the experiments. The tests showed that several of the combinations tested had desirable properties, which resulted in that it is hard to say what combination is the best, because different properties are sought for in defferent applications.

  • 120.
    Tjernström, Andreas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Platta på mark för passivhus: en jämförelse av U-värde och köldbryggor för prefabricerade grundelement2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The idea of passive house is based on creating as little heat loss as possible in a building. The many demands, especially energy requirements placed on passive houses means that the right choice of foundation could be of great importance since one of its functions is to be heat insulating. This work aimed to study and investigate three different foundation methods with slab for passive houses and their thermal insulation properties. The chosen methods were Koljern, Passiv husgrund and a slab designed by Sweco for a passive house in Umeå. Then facts, data and information was collected along with methods of calculations. Calculations by hand as well as computer calculations/simulations have been made. The results showed that Koljern- technology had the least thermal bridges but Passive house foundation had the lowest U-value, which means better thermal insulation capacity of the three methods included. It is then discussed about whether the choice of foundation method for passive houses can or should only be based on thermal insulation capacity. Comparisons regarding other characteristics and factors should be made and taken into consideration in the choice of foundation method.

  • 121.
    Vesterberg, Jimmy
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Industrial Doctoral School, Umeå University, Umeå, Sweden.
    Andersson, Staffan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    A single-variate building energy signature approach for periods with substantial solar gain2016In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 122, p. 185-191Article in journal (Refereed)
    Abstract [en]

    The use of regression analysis for the identification of building performance parameters based on measurements is often difficult due to collinearity between the outdoor temperature and the global solar radiation (S). This study proposes a method to overcome this issue. The proposed method is based on using the seasonal symmetry of S to pair data from time-periods equidistant from the winter solstice. In addition, a method to utilize synthetic data to fine-tune the paired-data approach is presented. To evaluate the paired-data approach, two years data from a multifamily building in Umeå was used to estimate the heat loss factor (air-to-air transmission including air leakage). The results were compared with results obtained when S was very low (S ≈ 0). It was found that, the fine-tuned paired-data approach resulted in a modest deviation in the heat loss factor with an average absolute deviation of 4.0%. The small deviation indicates that the paired-data approach can extend the use of single-variate regression models for accurate identification of heat loss factors to situations where the solar gain is substantial. The paired-data approach was also used to calibrate a commercial energy building simulation tool. 

  • 122.
    Vesterberg, Jimmy
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Andersson, Staffan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Robustness of a regression approach, aimed for calibration of whole building energy simulation tools2014In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 81, p. 430-434Article in journal (Refereed)
    Abstract [en]

    An approach, able to easily and effectively integrate field measured data in whole Building Energy Simulation (BES) models is crucial to increase simulation accuracy for existing buildings. In this paper the robustness of a linear regression method for extracting transmission losses above ground (including air leakage) and ground heat loss parameters are analyzed. The regression method is evaluated on two documented and monitored multifamily buildings with mechanical supply and exhaust ventilation systems, with and without heat recovery.   

    The obtained results are found to be robust, with variations less than 2% in the extracted estimates of transmission losses above ground (including air leakage) and with a high goodness of fit (R2>0.96) against measured data from two years. In addition, the estimations of the buildings ground heat loss were in good agreement with calculations in accordance with EN ISO 13370:2007. The high quality output from the used regression method serves as good prerequisites for the method to be used in conjunction with BES models to aid the analyst in a BES calibration process

  • 123.
    von Ahn, Mi
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Livscykelanalys med fokus på energianvändning under tillverkningsfasen - En jämförelse mellan stommaterial2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The construction industry accounts for a large part of Sweden's overall environmental impact in terms of energy consumption and emissions. As for the energy aspect, the focus has previously been to the energy efficiency of buildings during its operational phase when the earlier figures have shown that the operational phase accounts for 85 % of a building's total energy consumption. The buildings are being built denser and becoming more energy efficient in operation which has led to energy consumption today shifted in phase. New studies show that 50 % or more of a building's energy consumption today takes place in the manufacturing phase of the building and its components. Material choices and its manufacturing process thereof are of great importance. In this study three common framing materials has been examined and compared in terms of energy consumed during the manufacturing phase. The frames examined are concrete, steel combined with precast concrete and wood. The work had Umeå as a starting point, which meant that local manufacturers, suppliers and reference objects were studied. The processes studied are extraction, processing and transportation of raw materials, manufacture of materials including internal transportation and transportation of finished materials or components to Umeå. For comparative purpose a simplified life cycle assessment (LCA) of the three options was performed with the system boundary cradle-to-gate. The aim of the study was to show the advantages and disadvantages of the framing materials with the purpose to facilitate the selection of frame from an energy perspective. The results show that the difference in energy consumption is high among the options. The choice of frame or other structural component can thus play an important role throughout the building's total energy consumption. The concrete frame was most beneficial in this study, despite the high energy consumption by manufacturing cement. Wood is often considered a greener choice but the frame that was selected specifically for the study had higher energy consumption during the manufacturing process than the cement and concrete. The results also show that this kind of study is important to perform before each project when conditions are unique. However, this study only shows one aspect of the environmental impact that is caused by the alternatives, and only one phase of the life cycle. The result of studies such as this may vary depending on the choice of system limits and factors. Had the study also covered the final stage, i.e. decommissioning and waste management, the result would certainly have been different with the benefit of the wood frame on the basis of its energy content that is fully recyclable.

  • 124.
    Wallgren, Maria
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energifrågan under byggprocessen: Ett systematiskt arbetssätt för säkerställande av energianvändning i bostad2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The challenge of becoming more energy efficient in society has increased and the energy use requirements have become more stringent. In "Boverkets Byggregler" there are specific requirements for using energy in apartments on the basis of its location in the country and the heating system. These requirements, or other requirements from the customers, have to be met, otherwise they will result in high economic costs.

    How can a building contractor work to meet these requirements and thereby reduce the financial risks in a construction project? To sort this out, a study has been done to find out how NCC Construction Sverige AB carries out a construction process and acts with regard to the issue of energy. The requirements of energy use according to "Boverkets Byggregler" were examined in detail as well as demands for energy in the municipality, in this study, Umeå kommun. The thesis is limited to apartments built with turnkey contract where the specific energy use was measured 24 months after the handover.

    The study investigates, based on the energy issue, how the construction process generally is carried out, from sales through product planning, production and management. This is followed by a section investigating how the organization at NCC is structured regarding the issue of energy efficiency, how and why the information to all parties shall be presented as well as general factors that affect the energy use in a dwelling. The thesis is intended to be applicable and used as a tool by NCC for directing the energy issue during the building process. In extension, the thesis can be used as educational material within the company.

    The results of this study show that the most important issues for having a systematical way of working with ensuring energy use are the following:

     To appoint responsible people for follow-up of energy use.

     To do an early calculation of energy use.

     To make the project planning result in energy efficient solutions and ensure the execution of these solutions.

     To do follow-up of specific energy use.

     To educate all the involved people about the energy issue.

    To carry out the project based on these issues, a systematic way of working is needed, as well as a structured organization where it is clear who is responsible for each part of the project. A summary of this can be found in the schematic figures "Energipilen" and "Uppföjningspilen", see attachments III and IV. Furthermore, the study showed that the people who live in the apartment have a major impact on the energy use depending on their habits. Therefore, they must be offered an education about

    energy use.

    The solutions of project planning and the users

    ' habits are the factors the author considers to be

    the most critical to energy use. The author has also come to the conclusion that this is

    one way to

    ensure a limited energy use. The future will expect more stringent requirements on energy and the

    approach needs to be constantly updated. In addition, the study has shown that education with

    regards to energy use is necessary for the employees at the organization observed.

  • 125. Wang, Faming
    et al.
    Xu, Pengjun
    Ke, Ying
    Lin, Li-Yen
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Novel body mapping Nanoporous PE clothing for improving thermal comfort of office workers in indoor environments2017Conference paper (Refereed)
  • 126. Wang, Jinliang
    et al.
    Chow, Tin-tai
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Zhang, Hui
    Study on the impact of circulating nurse walking on bacteria-carrying particles distributions in operating theatre2016In: 14th International Conference on Indoor Air Quality and Climate (INDOOR AIR 2016), International Society of Indoor Air Quality and Climate ( ISIAQ ) , 2016, p. 354-361, article id 798Conference paper (Refereed)
  • 127.
    Wikner, Per
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Logistik och just-in-time - En utvärdering av OF Bygg i Umeå.2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna studie behandlar logistik och materialhantering med fokus på just-in-time-leveranser (JIT). Via intervjuer har data samlats in för att besvara forskningsfrågan; hur arbetar OF med JIT idag och finns det möjligheter till förbättring? Idag använder de inte JIT i någon större utsträckning, men ser en potential i metoden. Det framkom flera eventuella hinder för en renodlad implementering av JIT, främst relaterade till resurser och planering. Resultatet av studien blev att det finns möjligheter att utveckla arbetet med JIT, utan att en renodlad strategi för JIT införs. Det finns alternativ där material levereras i så nära anslutning det går, utan att de nödvändigtvis behöver monteras direkt. Detta innebär lagerbildning under kortare perioder på upplag för separata material som bör vara markerade. Att mellanlagra materialet är en väl fungerande metod som fyller syftet för JIT-leveranser, men tar inte vara på dess fulla potential. Kostnaden är fortfarande densamma i försörjningskedjan, samtidigt som kedjan inte förkortas. Om en JIT-implementering är önskvärd bör denna strategi fortgå medan relationer med leverantörer bildas, avtal sluts och utbildning av berörd personal sker.

  • 128. Xiong, Jing
    et al.
    Li, Angui
    Liu, Changping
    Dong, Jungang
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ren, Tong
    Cao, Junji
    Discovery of environmental secrets for historical artefacts: how did micro-climate evolve in ancient tombs in initial phase2018Conference paper (Refereed)
  • 129.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Building Services Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, China.
    Cheng, Xiaogang
    Dai, Dengxin
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Meier, Alan
    Real-time and contactless measurements of thermal discomfort based on human poses for energy efficient control of buildings2019In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 162, article id 106284Article in journal (Refereed)
    Abstract [en]

    Individual thermal discomfort perception gives important feedback signals for energy efficient control of building heating, ventilation and air conditioning systems. However, there is few effective method to measure thermal discomfort status of occupants in a real-time and contactless way. A novel method based on contactless measurements of human thermal discomfort status was presented. Images of occupant poses, which are related to thermoregulation mechanisms, were captured by a digital camera and the corresponding 2D coordinates were obtained. These poses were converted into skeletal configurations. An algorithm was developed to recognize different poses related to thermal discomfort, such as hugging oneself or wiping sweat off the brow. The algorithm could recognize twelve thermal discomfort related human poses. These poses were derived from a questionnaire survey of 369 human subjects. Some other human subjects participated in the validation experiments of the proposed method. All twelve thermal discomfort related poses can be recognized effectively.

  • 130.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lin, Zhang
    Li, Angui
    Advanced ventilation systems − theory, practice, limitations and solutions (Editorial)2018In: Trends in Civil Engineering and Material ScienceArticle in journal (Refereed)
  • 131.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Melikov, Arsen
    Technical University of Denmark.
    Sekhar, Chandra
    National University of Singapore.
    Performance evaluation of ceiling mounted personalized ventilation system2009In: ASHRAE Transactions, ISSN 0001-2505, Vol. 115, no 2, p. 395-406Article in journal (Refereed)
  • 132.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    A questionnaire survey on sleeping environment conditioned by different cooling modes in multistory residential buildings of Singapore2017In: Indoor + Built Environment, ISSN 1420-326X, E-ISSN 1423-0070, Vol. 26, no 1, p. 21-31Article in journal (Refereed)
    Abstract [en]

    A good sleep environment is essential to maintain a person's health and daily working performance. How to create comfortable and healthy sleep environments with less energy use is worth exploring. Findings, based on one questionnaire survey on sleep environments conditioned by different cooling modes have been reported. The study investigated the use of different cooling devices in relation to the effect on sleep. Human responses to thermal environments and air quality created by different cooling modes were also studied. Totally 229 completed questionnaires were statistically analysed. The results show that most of the respondents prefer to use air conditioner 3–6 months in a year with relatively low temperature settings especially for respondents living below fifth floor. It is better to choose relatively high temperature settings to reduce air conditioning intensity especially for elders and outdoor workers, which can not only avoid cold thermal discomfort but also reduce electric energy use. For elders, outdoor workers and persons living in higher floor levels, there was an increase usage of electrical fans or natural ventilation. Thermal comfort can be maintained by raised air movement and the perceived air quality could improve obviously by introducing outdoor air, which would create a good sleep environment to ensure sleep quality.

  • 133.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    A questionnaire survey on sleeping environment under different cooling modes in multi-story residential buildings of Singapore2015Conference paper (Refereed)
    Abstract [en]

    Good sleeping environment is important to guarantee person’s health and performance. How to create comfortable and healthy sleeping environment with less energy use is worth exploring. Findings, based on one questionnaire survey on sleeping environment conditioned by different cooling modes (split system air conditioning unit, different kinds of electrical fans or purely natural ventilation), were reported. The study aimed to investigate human factors such as bedding and sleepwear use, using habits of different cooling devices, and human responses to thermal environment and air quality created by different cooling modes. 290 effective questionnaires were collected between June 2013 and May 2014, which were statistically analyzed. The results showed that most of the respondents prefer to use air conditioner for certain number of hours with relatively low temperature settings especially for respondents living below 5th floor. For respondents living above 10th floor, the number of hours using electrical fan or purely natural ventilation increase and their perceived air quality improve obviously. Respondents, who work outdoors during daytime, use less time for air conditioner with relatively high temperature setting. Elder respondents above 55 seldom use air conditioner.

  • 134.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Field study of thermal comfort in a primary school under subarctic Sweden2018Conference paper (Refereed)
  • 135.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Outdoor thermal bioclimatic environments and human behavior pattern under subarctic climate of north Sweden: a pilot study in Umeå2016In: 14th International Conference on Indoor Air Quality and Climate (INDOOR AIR 2016), International Society of Indoor Air Quality and Climate (ISIAQ) , 2016, Vol. 6, p. 3745-Conference paper (Refereed)
  • 136.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nair, Gireesh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kabanshi, Alan
    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. Practical implications: The pilot study demonstrated that wind attenuation together with strong sunshine can improve Thermal Sensation Vote (TSV), which could be realized by specially designed hump terrain for attenuating wind without shading effects. The results will be used for optimizing design of urban outdoor environments such as parks under subarctic or arctic climate.

  • 137.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, China.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Wang, Faming
    Lu, Weizhuo
    Thermal comfort in primary school classrooms: A case study under subarctic climate area of Sweden2018In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 135, p. 237-245Article in journal (Refereed)
    Abstract [en]

    Limited studies were focused on primary school buildings especially under subarctic climate. Thermal comfort of children was assumed to be similar as that of adults, which may cause inaccuracy. To fill data blank and enrich global database, a field study was performed from late fall 2016 to early spring 2017 covering whole heating period in north part of Sweden. Indoor CO2 concentration was continuously monitored to evaluate indoor ventilation. Thermal comfort related parameters were continuously measured and predicted mean vote (PMV) was calculated. Subjective questionnaire surveys were performed every week except holidays. Subjective thermal sensation value (TSV) was always higher than objective PMV, which reflected thermal adaptation. The thermal adaptation became not obvious in middle and late winter because of long term exposure to heating environments. Heating system should be intensified gradually in early heating period, operated based on actual outdoor climate instead of experience in middle and late heating periods, extended under part load operation in early spring if necessary. The new 13-point TSV scale was pointed out by other researchers and tested inthis study, which can explore tiny TSV deviations from thermally neutral status and reflect more accurate thermal sensations.

  • 138.
    Yang, Bin
    et al.
    Hebei University of Technology, China.
    Sekhar, Chandra
    National University of Singapore.
    Conventional and ceiling mounted personalized ventilation-the dynamic effects of a moving person on personal exposure effectiveness2014In: Advanced Materials Research, ISSN 1022-6680, E-ISSN 1662-8985, Vol. 935, p. 333-336Article in journal (Refereed)
    Abstract [en]

    Ceiling mounted personalized ventilation (PV) aims to provide clean outdoor air into breathing zone of occupants directly without affecting indoor aesthetics. High momentum, at outlet of PV air terminal device (ATD), is utilized in order to avoid inducing more ambient air and let more personalized air come into breathing zone. In steady state, its performance depends much on the ceiling mounted ATD because supply air momentum, other than buoyancy effects and ambient air flow, is the major driving force in the micro-environment of occupied zone. In dynamic state, the movement of a person near PV ATD causes entrainment or detrainment effect, which can be regarded as another comparable factor influencing ceiling mounted PV performance. A typical office workplace consisting of either ceiling mounted PV ATD or conventional PV ATD and ambient air supply diffuser is simulated. One person is assumed to be seated and another moving person is simulated by dynamic meshes in computational fluid dynamics (CFD). Simulations at moving person velocities of 0.5, 1 and 1,5 m/s and distance between seated person and moving person of 0, 0.2, 0.4m are performed. A new index, computational personal exposure effectiveness, is utilized to assess the performance of the PV ATD in regard to inhaled air quality under the influence of moving person. According to numerical results, the stability of ceiling mounted PV, under dynamic environment with moving person, is better than that of conventional PV although the personal exposure effectiveness (PEE) is lower than that of conventional PV with the same personalized air flow rate in steady state.

  • 139.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Sekhar, Chandra
    National University of Singapore.
    Human perception relation between thermal comfort and air movement for ceiling mounted personalized ventilation system2014In: Advanced Materials Research, ISSN 1022-6680, E-ISSN 1662-8985, Vol. 935, p. 329-332Article in journal (Refereed)
    Abstract [en]

    As one kind of newly developed personalized ventilation (PV) system, the relation was explored between thermal comfort and air movement perception/acceptability/preference with tropical subjects, who had become passively acclimatized to hot conditions in the course of their day-to-day life. The tests were conducted in field environmental chamber (FEC) of National University of Singapore. 32 subjects (16 males and 16 females), performed normal office work, can choose to expose to four different PV airflow rates (4, 8, 12, 16 L/s) so as to simulating individual control. Ambient temperatures of 26°C and 23.5 °C and PV air temperatures of 26 °C, 23.5 °C and 21 °C were utilized to conduct parametric variation studies. Each combination was maintained for 15 minutes during which the subjects responded to computer-administered questionnaires. Under different PV airflow rates and ambient/PV temperature combinations, the relation between thermal comfort and air movement perception/acceptability/preference was analyzed.

  • 140.
    Yang, Bin
    et al.
    Department of Building Services, Hebei University of Technology, Tianjin, China.
    Sekhar, Chandra
    National University of Singapore.
    Interaction of dynamic indoor environment with moving person and performance of ceiling mounted personalized ventilation system2013In: Indoor + Built Environment, ISSN 1420-326X, E-ISSN 1423-0070, Vol. 23, no 7, p. 920-932Article in journal (Refereed)
    Abstract [en]

    Ceiling mounted personalized ventilation (PV) aims to provide clean outdoor air into human breathing zone without affecting indoor aesthetics in energy-efficient manner. In steady state, its performance depends much on the ceiling mounted air terminal device (ATD) because supply air momentum, other than human body thermal plume and ambient air flow, is the major driving force in the micro-environment of occupied zone. A typical office workplace consisting of ceiling mounted PV ATD and ambient air supply diffusers was simulated. One person was seated and another moving person was simulated by dynamic meshes in computational fluid dynamics (CFDs). A new index, computational personal exposure effectiveness (PEEc), was utilized to assess the performance of ceiling mounted PV system in regard to inhaled air quality under influence of moving person. Meanwhile, influence of evenly distributed ceiling mounted PV ATDs on inhaled air quality was also studied. According to numerical results, stability of ceiling mounted PV under dynamic environment with moving person was acceptable with minor changes of PEEc and inhaled air quality could be improved over larger occupied area for both seated person and moving person.

  • 141.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Sekhar, Chandra
    National University of Singapore.
    Numerical algorithm studies of CFD modeling for a compartmented cooling coil under dehumidifying conditions2007In: Numerical Heat Transfer, Part A Applications, ISSN 1040-7782, E-ISSN 1521-0634, Vol. 52, no 8, p. 737-755Article in journal (Refereed)
  • 142.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Sekhar, Chandra
    National University of Singapore.
    The influence of evenly distributed ceiling mounted personalized ventilation devices on indoor environment2008In: The International Journal of Ventilation, ISSN 1473-3315, E-ISSN 2044-4044, Vol. 7, no 2, p. 99-112Article in journal (Refereed)
  • 143.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Sekhar, Chandra
    National University of Singapore.
    Three-dimension numerical simulation of a hybrid fresh air and re-circulated air diffuser for decoupled ventilation strategy.2007In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 42, no 5, p. 1975-1982Article in journal (Refereed)
  • 144.
    Yang, Bin
    et al.
    Department of Building, School of Design and Environment, National University of Singapore, Architecture Drive 4, Singapore; International Center for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Building 402, DK-2800 Lyngby, Denmark.
    Sekhar, Chandra
    National University of Singapore.
    Melikov, Arsen
    Technical University of Denmark.
    Ceiling mounted personalized ventilation system in hot and humid climate-An energy analysis2010In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 42, no 12, p. 2304-2308Article in journal (Refereed)
    Abstract [en]

    This study is to evaluate energy saving potential of ceiling mounted personalized ventilation (PV) system in conjunction with background mixing ventilation compared with mixing ventilation system alone and with mixing ventilation system when occupants are provided with individually controlled desk fans for generating additional air movement at each desk. Control strategy applied includes different number of personalized ventilation air terminal devices used and different PV airflow rates supplied. Energy calculation is based on design conditions in Singapore, representing a hot and humid climate. The results reveal that increasing room temperature can save cooling energy when the combination of PV with ceiling mounted personalized ventilation nozzles and background mixing ventilation is used. In this case the energy for transport of air increases but the total energy decreases, i.e. energy can be saved due to elevated room temperature. Comparing with mixing ventilation plus desk fans, ceiling mounted personalized ventilation cannot only realize better cooling effect but also decrease the total energy consumption.

  • 145.
    Yang, Bin
    et al.
    Department of Building, School of Design and Environment, National University of Singapore, Singapore; 2 Technical University of Denmark, Department of Civil Engineering, International Center for Indoor Environment and Energy, Nils Koppels Alle, Lyngby, Denmark.
    Sekhar, Chandra
    National University of Singapore.
    Melikov, Arsen
    Technical University of Denmark.
    Ceiling mounted personalized ventilation system integrated with a secondary air distribution system-A human response study in hot and humid climate2010In: Indoor Air, ISSN 0905-6947, E-ISSN 1600-0668, Vol. 20, no 4, p. 309-319Article in journal (Refereed)
    Abstract [en]

    The benefits of thermal comfort and indoor air quality with personalized ventilation (PV) systems have been demonstrated in recent studies. One of the barriers for wide spread acceptance by architects and HVAC designers has been attributed to challenges and constraints faced in the integration of PV systems with the work station. A newly developed ceiling‐mounted PV system addresses these challenges and provides a practical solution while retaining much of the apparent benefits of PV systems. Assessments of thermal environment, air movement, and air quality for ceiling‐mounted PV system were performed with tropically acclimatized subjects in a Field Environmental Chamber. Thirty‐two subjects performed normal office work and could choose to be exposed to four different PV airflow rates (4, 8, 12, and 16 L/s), thus offering themselves a reasonable degree of individual control. Ambient temperatures of 26 and 23.5°C and PV air temperatures of 26, 23.5, and 21°C were employed. The local and whole body thermal sensations were reduced when PV airflow rates were increased. Inhaled air temperature was perceived cooler and perceived air quality and air freshness improved when PV airflow rate was increased or temperature was reduced.

    Practical Implications: The newly developed ceiling‐mounted PV system offers a practical solution to the integration of PV air terminal devices (ATDs) in the vicinity of the workstation. By remotely locating the PV ATDs on the ceiling directly above the occupants and under their control, the conditioned outdoor air is now provided to the occupants through the downward momentum of the air. A secondary air‐conditioning and air distribution system offers additional cooling in the room and maintains a higher ambient temperature, thus offering significant benefits in conserving energy. The results of this study provide designers and consultants with needed knowledge for design of PV systems.

  • 146.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, China.
    Wang, Faming
    Supplementary opinions on alternative cooling technologies in hot climate2018In: International Journal of Biometeorology, Vol. 62, p. 1927-1928Article in journal (Refereed)
  • 147.
    Yang, Bin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Wang, Sihan
    Yu, Shuren
    Olofsson, Thomas
    Climatic barriers and adaptation to winter soft-mobility and polar tourism: a pilot study in Umeå, Sweden.2018Conference paper (Refereed)
  • 148. Yu, Zhun
    et al.
    Li, Jun
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Zhang, Guoqiang
    Temporarily occupied space with metabolic-rate-initiated thermal overshoots: A case study in railway stations in transition seasons2017In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 122, p. 184-193Article in journal (Refereed)
    Abstract [en]

    Temporarily occupied space (TOS) is defined as an air-conditioned space in which most of occupants stay for less than a certain period (e.g., 40 min), such as post offices, supermarkets, bookstores, and banks. The definition mainly emphasizes two aspects: obvious temperature step up/down and short-term exposure periods. Typical TOSs with predominantly temperature-initiated thermal overshoots have been explored in previous studies. Indeed, apart from temperature-initiated thermal overshoots, thermal overshoots can also be initiated by other parameters, such as metabolic rates. In this view, the definition of thermal overshoots was generalized and a case study was conducted at high-speed railway station in China under conditions of transition seasons. The phenomenon of metabolic-rate-initiated thermal overshoots instead of temperature-initiated thermal overshoots was observed and explored, based on objective measurements and subjective questionnaire surveys. The results could optimize the design and operation of air conditioning and mechanical ventilation (ACMV) systems in such TOSs as embodied by railway stations. In addition, the probit analysis method for analyzing neutral temperature ranges instead of neutral temperature points was also discussed.

  • 149. Yu, Zhun
    et al.
    Li, Jun
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Zhang, Guoqiang
    Temporarily occupied spacewith metabolic-rate-initiated thermal overshoots: a case study in railwaystations in transition seasons2017In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 122, p. 184-193Article in journal (Refereed)
    Abstract [en]

    Temporarily occupied space (TOS) is defined as an air-conditioned space in which most of occupants stay for less than a certain period (e.g., 40 min), such as post offices, supermarkets, bookstores, and banks. The definition mainly emphasizes two aspects: obvious temperature step up/down and short-term exposure periods. Typical TOSs with predominantly temperature-initiated thermal overshoots have been explored in previous studies. Indeed, apart from temperature-initiated thermal overshoots, thermal overshoots can also be initiated by other parameters, such as metabolic rates. In this view, the definition of thermal overshoots was generalized and a case study was conducted at high-speed railway station in China under conditions of transition seasons. The phenomenon of metabolic-rate-initiated thermal overshoots instead of temperature-initiated thermal overshoots was observed and explored, based on objective measurements and subjective questionnaire surveys. The results could optimize the design and operation of air conditioning and mechanical ventilation (ACMV) systems in such TOSs as embodied by railway stations. In addition, the probit analysis method for analyzing neutral temperature ranges instead of neutral temperature points was also discussed.

  • 150. Yu, Zhun
    et al.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Zhu, Neng
    Effect of thermal transient on human thermal comfort in temporarily occupied space in winter: a case study in Tianjin2015In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 93, no 2, p. 27-33Article in journal (Refereed)
    Abstract [en]

    The acceptable temperature ranges of temporarily occupied space (TOS) such as supermarkets could be different from the ranges of normal indoor spaces such as offices. However, current thermal comfort standards do not distinguish such a space from normal spaces and identify its design temperature range clearly. This study proposed TOS, and explored human responses to TOS with the ultimate goal of finding its optimal design temperature range in winter. Questionnaire surveys were performed at six temperature levels in a climatic chamber in Tianjin. Human participants were exposed to outdoors for 20 min and then they stayed in the chamber for 40 min. During this period their thermal sensation, comfort and preference were recorded for evaluation at five different time points. The study shows that their neutral temperature ranges from 16.9 °C to 18.4 °C. Their thermal preference maintains “no change” in the range of 15.4 °C–19.3 °C. Meanwhile, from the viewpoint of thermal comfort, a temperature range of 15.4 °C–17.4 °C is highly desirable for occupants to stay in TOS. Considering the above three ranges, the optimal design temperature range for TOS in Tianjin is recommended to be 16.9 °C–17.4 °C, which achieves highly desirable thermal comfort, neutral thermal sensation and “no change” thermal preference simultaneously. This range is significantly lower than the design temperature range in Chinese national codes (20 °C–22 °C). The results of this study can be used as reference for future code formulation and building retrofitting.

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