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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Jämförelse mellan vattenburet och luftburet kylsystem i kontorslokaler : Med hänsyn till energibehov och komfort / Comparison of water-borne - and airborne climate systems in offices : In view of energy and comfort

Henning, Anton January 2016 (has links)
The work has been carried out in cooperation with Swegon AB, the market leader for ventilation and indoor climate business. For work have their own programs ESBO be used to simulate and on the way to compare different systems.   The annual energy use in the world is constantly increasing. This leads to our already highly stressful climate will be affected even more. Therefore it is of great importance to work on energy issues and to try to find ways to reduce energy consumption, and thus work towards a sustainable society from an environmental perspective.   The indoor climate is an important parameter for the well-being, and if the indoor climate does not meet the requirements it can lead to poorer performance and lack of concentration for the people staying in the room. The energy that is used to reach this arbitrary indoor climate is increasing rapidly in the world and therefore is the efficiency of comfort climate systems desirable.   The aim of this study is to, by using simulations; compare a waterborne and airborne climate system in terms of energy and comfort.   The object of the study is to compare a water-borne and airborne cooling system, and then to compare the energy use and comfort of these systems. This will be done by simulations with different sized internal heat loads and different levels of carbon dioxide. Finally, a comparison shall be entered where the different systems solutions placed in four different climate zones to provide knowledge about which system works best in which zone.   The simulations have been performed in the program ESBO, which with given conditions calculates the need for cooling, heating and energy for pumps and fans in a room.   An office building has been created in ESBO with dimensions of 4 x 2.5 x 2.6 (length, width and height). The office has a window facing south. The office is assumed to be a part of a building, this leads to that no heat exchange takes place indoors. The internal heat in the room consists of lighting, appliances, personal warmth, but also solar radiation. Schedules have been used for lighting, appliances and personal warmth. It was built four different systems then compared. These were two airborne system, a CAV system that cools with constant ventilation flow. A VAV system that cools with a variable ventilation flow. It was also built up a waterborne system, which cools the room by using a chilled beam. A combined system was also built up where the air is cooled by both chilled beam and ventilation.   The result shows that different systems will be preferred in different cases. The combined system will be preferred at low internal heat loads. The chilled beam system will keep the best comfort, but in the meantime it is the system that will require the greatest amount of energy in all the simulations. CAV systems can´t cope with the requirements of the temperature in the simulations. VAV systems are to be preferred at high internal heat loads.
2

I de lugnaste vatten : Hur allmänheten påverkades av Cryptosporidium i Östersund

Burman, Malin, Carleson, Mattias January 2012 (has links)
Människor har olika riskuppfattningar beroende på tidigare erfarenheter, kulturell bakgrund och kunskap. Riskuppfattningarna kan skilja sig så att vissa människor upplever en inträffad händelse som en kris, medan andra upplever samma sak som en allvarlig händelse. Vid en kris eller allvarlig händelse prioriteras inte allmänhetens uppfattningar eller åsikter när ansvariga aktörer och myndigheter arbetar för att hitta orsaken till händelsen. Eftersom allmänheten är en stor grupp i samhället och är de som drabbas vid en kris eller allvarlig händelse, vill vi med denna studie undersöka hur de uppfattade det vattenburna Cryptosporidiumutbrottet i Östersund som pågick från november 2010 och tre månader framåt. För att genomföra studien har vi analyserat kvantitativa data från vår egen surveyundersökning som har genomförts med hjälp av enkäter. Den teoretiska referensram som ligger till grund för uppsatsen behandlar riskuppfattning samt kopplingar till risksamhället. De resultat som vi fick fram av studien visar att det finns signifikanta skillnader mellan ålder och hur man påverkades av Cryptosporidiumutbrottet, då i synnerlighet yngre påverkades mer av parasiten. Vidare finns stöd för detta resultat i tidigare forskning, som understödjer resonemanget att framförallt yngre personer påverkas mer av Cryptosporidium än äldre. Nyckelord: Vattenburen smitta, Cryptosporidium hominis, parasitutbrott, riskuppfattning och risksamhälle.
3

Projektering av ett småhus med fördjupning i uppvärmningssystem

Dahlin, Tobias, Hedlin, My January 2012 (has links)
No description available.
4

Undersökning av komfortkyla i en kontorsfastighet

Eriksson, Daniel, Karlsson, Jörgen Unknown Date (has links)
<p>The use of air-conditioning and comfort cooling in offices and stores has been increasing during recent years. Adnot, (2002) reports an increased use in commercial buildings by 200 % from 1990 to 2002. The increase is primarily due to the growing use of electrical equipment generating internal heat. The enhanced public demands of the indoor climate are yet another explanation to the increase. The main cooling method used is mechanical chillers based on vapor compression. Many of these cooling systems are old and will shortly become obsolete which gives the property holder a chance to improve in his cooling system.</p><p>The office building Mercurius 12 in Karlstad operates activities that require comfort cooling. The cooling method used is conventional vapor compression which is distributed by an airborne system. The property consists of two buildings one built in 1939 and one in 1970. The property is 7700 m<sup>2</sup> and accommodates one apartment, offices and stores. The property is currently housing 190 people.</p><p>The aim of this report is that on a basis of life-cycle costs analyze how a change of cooling methods and cooling needs are connected to the Life-cycle costs of the cooling. The practicability of each change shall also be investigated.</p><p>The calculation of the life-cycle costs and heat surpluses have been made using generally accepted formulas that has been outlined in Excel.</p><p>All of the simulated measures to reduce the building's life-cycle costs in terms of internal heat and solar radiation pays off. The higher energy prices, the greater savings.</p><p>The Cooling tower method is the chilling process that provides the minimum life-cycle costs, both with both air and waterborne distribution system.</p><p>Vapor compression used with today’s energy prices provides comparatively to the other investigated methods a low life-cycle cost. The vapor compression method is however not as good if the energy price would get higher than today.</p>
5

Undersökning av komfortkyla i en kontorsfastighet

Eriksson, Daniel, Karlsson, Jörgen Unknown Date (has links)
The use of air-conditioning and comfort cooling in offices and stores has been increasing during recent years. Adnot, (2002) reports an increased use in commercial buildings by 200 % from 1990 to 2002. The increase is primarily due to the growing use of electrical equipment generating internal heat. The enhanced public demands of the indoor climate are yet another explanation to the increase. The main cooling method used is mechanical chillers based on vapor compression. Many of these cooling systems are old and will shortly become obsolete which gives the property holder a chance to improve in his cooling system. The office building Mercurius 12 in Karlstad operates activities that require comfort cooling. The cooling method used is conventional vapor compression which is distributed by an airborne system. The property consists of two buildings one built in 1939 and one in 1970. The property is 7700 m2 and accommodates one apartment, offices and stores. The property is currently housing 190 people. The aim of this report is that on a basis of life-cycle costs analyze how a change of cooling methods and cooling needs are connected to the Life-cycle costs of the cooling. The practicability of each change shall also be investigated. The calculation of the life-cycle costs and heat surpluses have been made using generally accepted formulas that has been outlined in Excel. All of the simulated measures to reduce the building's life-cycle costs in terms of internal heat and solar radiation pays off. The higher energy prices, the greater savings. The Cooling tower method is the chilling process that provides the minimum life-cycle costs, both with both air and waterborne distribution system. Vapor compression used with today’s energy prices provides comparatively to the other investigated methods a low life-cycle cost. The vapor compression method is however not as good if the energy price would get higher than today.
6

Kollektivtrafik på svaj : En fallstudie för ökad tillgänglighet vid långa bytessträckor med fokus på vattenburen kollektivtrafik / Public Transport Adrift : A Case Study for Increased Accessibility at Long-distance Transfers with a Focus on Public Transport on Water

Deurell, Göran January 2016 (has links)
Vattenburen kollektivtrafik tenderar att ha längre bytessträckor än buss och spårtrafik. Då långa byten kräver mer av resenären är uppsatsens syfte att undersöka hur bytet till och från pendelbåtar kan se ut vid en för trafiken större bytespunkt. Därigenom kanske vi kan lära oss mer om resenärens informationsbehov vid byten över längre avstånd. Därtill har målet varit att presentera rekommendationer som kan stärka förutsättningarna för vattenburen kollektivtrafik, med särskilt fokus på bryggan (angöringspunkten) vid Klara Mälarstrand och den närliggande järnvägsstationen Stockholm Central. Arbetet har utförts i form av en fallstudie som undersökte platsen utifrån upplevd närhet och -tydlighet, med empiri bestående av egentagna bilder, kartor, avståndsmätningar samt dokument. Datainsamlingen pågick under lång tid, parallellt med Trafiknämndens egna utredningar av trafik till och från bryggan. Analysen visade att bryggan vid Klara Mälarstrand är bristfälligt integrerad med omgivande kollektivtrafik och att en tydlig vägledning saknas. I diskussionen förs ett resonemang om vikten av att entréer till kollektivtrafiken, exemplifierat av pendeltågens nya station Stockholm City, synliggör sin funktion även på långt håll. Resenärer bör även ges möjlighet att relatera längre bytessträckor till en tidsåtgång, liknande den ’uppskattad gåtid till gate’ som används på storflygplatser som Köpenhamns flygplats Kastrup. / Public transport on water tend to have longer transfer paths than bus and rail transport. As long transfers paths demands more from the passenger this thesis aims to investigate what a transfer to and from water buses may look like at a transfer point with public transport on water of major importance for a planned service in Stockholm, Sweden. Through that more knowledge about the information needs of passengers at transfers over longer distances might be gained. In addition the thesis aims to present recommendations which can strengthen the conditions for public transport on water, with a focus on the stop (quay) near the Stockholm Central station. The thesis has been carried out as a case study which examined the study area on the basis of perceived proximity and -legibility,with empirics consisting of images taken by the author, maps, distance measurements and documents. Data collection time has been long, in parallel with the Stockholm County Administrations (SLL) own investigations of the traffic. The analysis showed that the quay at Klara Mälarstrand has a lacking integration with surrounding public transport and that a clear wayfinding is missing. In the discussion an argument for the importance of legible entrances to public transport also at a distance is made, exemplified by the new Stockholm City commuter train station building. Also passengers at longer transfer paths needs to be able to relate the distance with the time to get there, similar to the ‘approximate walking time to gate’ used at major airports such as Copenhagen Airport, Kastrup in Denmark.
7

Golvvärme eller radiatorer : Vattenburna värmesystem i flerbostadshus / Underfloor heating or radiators : Waterborne heating systems in apartment blocks

Tanik, Ahmet, Schedin, Richard January 2017 (has links)
I flerbostadshus är radiatorer det vanligaste uppvärmningssystemet. Inte alls många har golvvärme i deras lägenheter. I dagens nyproduktion av flerbostadshus bygger man för det mesta husen med radiatorer och har elburen golvvärme som komfortvärme i badrummen. I villor är det däremot mycket vanligare att man använder sig av vattenburen golvvärme över större delen av huset. Detta examensarbete undersöker varför det inte används golvvärme lika mycket i flerbostadshus, det undersöker även intresset för privatpersoner att ha golvvärme i lägenheter samt om dessa personer isåfall hade kunnat tänka sig betala mer pengar om de fick vattenburen golvvärme installerat vid nyproduktion.Resultaten har fåtts fram genom en enkätundersökning samt intervjuer där vi intervjuat kunniga inom området. Våra resultat visar att nästan 40% av de enkät intervjuade hade velat ha endast golvvärme som uppvärmningssystem medan ungefär 55% hade velat ha både radiatorer och golvvärme som ett gemensamt uppvärmningssystem. De flesta hade då velat ha golvvärme i bland annat toalett, badrum, hall, kök, vardagsrum och sovrum. Resultaten visar även att nästan hälften av de enkät besvarande hade kunnat tänka sig betala mer för en bostad med golvvärme medan den större delen av den andra hälften var osäkra och förmodligen behövde mer tid för att tänka. Resultaten gällande varför man inte använder vattenburen golvvärme i lägenheten lika ofta som man använder radiatorer visade sig variera lite mellan de intervjuade vilket vi tror har med erfarenheter att göra men att ett golvvärmesystem var installationsmässigt dyrare än ett radiatorsystem verkade vara huvudsaken. / In prefabricated apartment blocks the most common thing people have in their homes is radiators as their waterborne heating system but very few have underfloor heating in their apartments. Nowadays the most usual thing to do is to install radiators and have underfloor electric heating in the bathrooms. Most residentials however usually have waterborne underfloor heating across the bigger part of the house. This report digs into why underfloor heating isn’t being used as often in apartment buildings, it also investigates people’s interest to have underfloor heating in apartment buildings plus if they then would be interested in paying more for a new apartment with waterborne underfloor heating.The outcome from our results has been achieved through a survey and interviews where we have questioned competent persons within the sector. Our results show that 40% of the people in the survey would like to have only underfloor heating as their waterborne system while 55% of the people would like to have a combined system with both radiators and underfloor heating. Most of them preferred to have underfloor heating in their toilets, bathrooms, entrance hall, kitchen, living room and bedroom. The results also show that almost half the persons in the survey could pay more money for a place with underfloor heating while the bigger part of the other half weren’t sure and probably needed more time to think. Our outcome on why waterborne underfloor heating in apartment buildings isn’t being used as often as radiators showed to differ between the interviewed persons which we assume have to do with their different backgrounds and experience but the main reason seemed to do with the part that a waterborne underfloor heating system in an installation point of view is more expensive than a radiator system.
8

Simulering av vattenburen golvvärme med finita elementmetoden : värmeavgivning vid olika mönster för rörläggning / Simulation of Hydronic Underfloor Heating With the Finite Element Method : Heat Release From Different Heating Pipe Patterns in Construction

Nyberg, Joakim January 2023 (has links)
This report formulates the boundary conditions and discretization method for conducting a simulation of heat with liquids and solids through the finite element method. It introduces the reader to the movement that is due today with optimization of heat transport and mitigation generally described as the fourth generation of district heating. It presents the scope: calculating the heat release from pipes in hydronic underfloor heating, and presents the belonging question: how does heat release from different heating pipe patterns affect the body’s heat transfer? Simulation of the work is conducted with the delimitations of using a single boundary slip condition addressing friction and only using water as pipe flow medium. It focuses on the pattern’s ability to affect the heat to the body, of which characteristically manifests a square concrete slab in the running simulations. By using different cases, it analyses how patterns using the same length of pipes emit their average heat to the covering top surface differently, both as the heating level alternates, and duration for response changes. This meanwhile they are affected by analog boundary temperature conditions.    A sensitivity analysis is done answering how the various patterns tested are affected by change of propagation speed for the flowing medium, showing that a spiral formed pattern with evenly spread piping is the least affected. The results show that the pattern with alternating pipe spacing gives the best average heat emission in the simulated cases. It also concludes that minor changes in the pattern area will have profound effect on the average transferred heat from the body’s top surface.
9

Stockholms vattenburna kollektivtrafik - vision 2020

Lindencrona, Henrik January 2011 (has links)
Varför har vi inte en mer utvecklad vattenburen kollektivtrafik i Stockholm, vad krävs för att en sådan ska bli verklighet och hur kan den komma att se ut. De frågorna är grunden i examensarbetet Stockholms vattenburna kollektivtrafik - Vision 2020.

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